A lot of individuals select to acquire a laptop computer online, in which consumers can discover a wider assortment and typically reduce prices. Which is fine, but you truly shouldn’t buy a fresh computer sight unseen in the event you can prevent it. Compose down the names of a few of the types you are thinking about, together with a couple of notes about why they caught your eye, and head to your nearby big-box electronics keep. See in the event the retailer has show models of any in the systems you’re taking into consideration, or a minimum of very comparable models through the exact same manufacturer. Check out the keyboard–can you type simply on it? May be the touchpad a soreness to make use of? Does the display screen search great? When the laptop computer you want to acquire includes a glossy display screen, look at other types with glossy screens and establish regardless of whether your present recipient may favor that appear more than a matte, antiglare finish.
Decide on up the laptop computer with long life latitude d620 battery ，latitude d820 battery . you would like to buy, and assess its heft. Near the lid and see if your dimension is something that the recipient can match into their picked bag (do not really place it within a bag, naturally, except you desire safety throughout you). Bear in mind that several show notebooks in stores possess the battery removed, which helps make them look substantially lighter.
After you have a experience for your preferred laptop (or even a very comparable one), it is possible to go again property and get on the web with self-confidence. If you’re purchasing inside a brick-and-mortar keep, you might wish to request when the retailer has any sales coming up, or a minimum of phone around to various stores to find out which 1 has the best price tag. Or use your mobile phone to check out the newest rates on the web, and see how competitive the in-store price is. The shop you choose may possibly even match the price of the regional competitor.
Want A lot more RAM? Get it done By yourself
Let’s say the laptop computer you need to get arrives with 2GB of RAM but is expandable to 4GB. You could be able to save some cash in the event you upgrade the laptop’s RAM oneself rather than purchasing the 4GB choice in the manufacturer. See just how much more it fees to purchase the machine with 4GB, and evaluate that with acquiring the RAM individually and setting up it (the activity normally demands getting rid of only a few screws and about five minutes of the time–it’s simple to do on most laptops these days).
By natural means, you will need to do some homework first. Be sure that the laptop computer has an empty RAM socket (consult a revenue rep if you are not sure),high quality latitude d830 Battery ,inspiron 510m battery and discover out what sort and speed of RAM you may require. If all of this looks intimidating, it really is okay–just buy the system together with the RAM upgrade. Your time and stress are value only so much.
In case your present recipient will want a spare battery, select one that is specifically manufactured to function together with the certain design of laptop. It is not a poor notion to buy the battery appropriate once you purchase the PC–especially if you are purchasing on the internet, in which an extra battery may be supplied as an option. Use caution in the event you purchase an aftermarket battery from a producer besides the one which produced the laptop computer: A number of these batteries are priced truly effectively but shop significantly less power. Go through person reviews and remarks about third-party batteries meticulously to generate positive you happen to be not sacrificing battery life to preserve some bucks.
As for external optical drives, will not experience obligated to purchase a single from the producer of the laptop computer. Exterior optical drives that hook up via USB are usually universal, so search around for the good price.
Amid other laptop equipment, take into account purchasing a modest, wireless journey mouse. Even the most effective touchpad can be quite a nuisance occasionally, and also you can uncover a lot of compact, vostro 1700 battery ,latitude d630 battery-operated wireless mice that are especially intended to journey which has a laptop computer. If your gift recipient wants to use a laptop mouse on an airplane, nevertheless, be aware that wireless versions are forbidden–they’ll require a wired design for use in-flight.
It is possible to probably steer clear of shelling out income on a specialized laptop computer bag or carrying situation, which retail stores often mark up quite a lot. Except you encounter an incredible bargain, or you find a specific scenario created just for the unusually huge or little laptop computer you’re buying as well as the present recipient would love to have it, bide your time. Buying a really excellent bag can be a entire other approach in itself–don’t get a thing the individual will hate just because it’s expedient and handy.
When the salesperson tries to push other folderol on you, like screen wipes, blank discs, and added cables, just say “no thank you.” These things almost often have a large markup in shops, and you happen to be typically greater off purchasing them online in the event you do not believe you may need them right away.
When In Doubt, Go Quicker
If, following going hands-on with a handful of laptops, you are just not sure no matter whether your present recipient wants a more rapidly processor, devoted graphics, or even more RAM, get the leap. No one ever before complained that their laptop computer was too fast, but shelling out the next couple of many years doing work on an annoyingly sluggish laptop computer will get old within a hurry. Expect application to be at any time far more resource-hungry with time, too; the apps that the laptop’s new operator will use subsequent year will most likely be considered a tiny much more demanding than what they use these days. And if they have an HDTV or they’re taking into consideration getting a single in the future, an HDMI output on the laptop may can be found in handy.
Most consumer-advocacy groups will tell you not to get an extended warranty; such an arrangement is usually an excellent profit-maker for the producers and stores that offer it, and most consumers will not end up making use of it. Since they’re this kind of great profit generators, salespeople will usually offer you the hard sell about how you want some kind of laptop safety system or extended warranty.
Be cautious. Before you decide to even feel about signing up, request a lot of concerns. Inquire to view the specifics about what exactly is coated and what isn’t in writing–don’t simply rely upon the word with the salesperson.
Laptops really are a small distinct than most buyer electronics,solar radio emergency,inspiron e1705 battery and desktop computers in that they’re, nicely, highly moveable. People are inclined to throw them into bags, toss them close to, accidentally knock them off tables, leave them to get poked and prodded by kids, and place them on the kitchen table, begging to become victimized by a horrific spill. Know your gift recipient and the surroundings wherever they will use their laptop computer. If you believe they’ve a substantial probability of destroying their laptop in a couple of decades, you may wish to take into account the extended warranty. (When we very last surveyed readers on their satisfaction with prolonged warranties, we located that customers who bought them have been quite satisfied.) Also, laptop theft safety plans could be a great concept for college college students, that have their laptops lost or stolen with alarming regularity.
2011年5月19日星期四
2011年5月18日星期三
Heat, Loading and Laptop Battery Life
Heat is a killer of all batteries and high temperatures cannot always be avoided. This is the case with a battery inside a laptop, a starter battery under the hood of a car and stationary batteries in a tin shelter under the hot sun. As a guideline, each 8°C (15°F) rise in temperature cuts the life of a sealed lead acid battery in half. A VRLA batteryfor stationary applications that would last 10 years at 25°C (77°F) would only live for five years if operated at 33°C (95°F). Once the battery is damaged by heat, the capacity cannot be restored. The life of a battery also depends on the activity and is shortened if the inspiron e1705 battery is stressed with frequent discharge.
According to the 2010 BCI Failure Mode Study, starter batteries have become more heat-resistant over the past 10 years. In the 2000 study, a change of 7°C (12°F) affected battery life by roughly one year; in 2010 the heat tolerance has widened to 12°C (22°F). In 1962, a starter inspiron e1705 battery lasted 34 months, and in 2000 the life expectancy had increased to 41 months. In 2010, BCI reports an average age of 55 months of use. The cooler North attains 59 months and the warmer South 47 months.
Cranking the engine poses minimal stress on a starter battery. This changes in a start-stop function of a micro hybrid. The micro hybrid turns the IC engine off at a red traffic light and restarts it when the traffic flows. This results in about 2,000 micro cycles per year. Data obtained from car manufacturers show a capacity drop to about 60 percent after two years of use in this configuration. To solve the problem, automakers are using specialty AGM and other variations that are more robust than the regular lead acid. Read more about Alternate Battery Systems. Figure 5 shows the drop in capacity after 700 micro cycles. The simulated start-stop test was performed in Cadex laboratories. CCA remains high.
Test method: The test inspiron e1705 battery was fully charged and then discharged to 70 percent to resemble the SoC of a micro hybrid in real life. The battery was then discharged at 25A for 40 seconds to simulate engine off condition at stoplight with the headlight on, before cranking the engine at 400A and recharging. The CCA readings were taken with the Spectro CA-12.
The cell voltages on a battery string must be similar, and this is especially important for higher-voltage VRLA batteries. With time, individual cells fall out of line, and applying an equalizing charge every six months or so should theoretically bring the cells back to similar voltage levels. While equalizing will boost the needy cells, the healthy cell get stressed if the equalizing charge is applied carelessly. What makes this service so difficult is the inability to accurately measure the condition of each cell and provide the right dose of remedy. Gel and AGM batteries have lower overcharge acceptance than the flooded version and different equalizing conditions apply. Always refer to the manufacturer’s specifications.
Water permeation, or loss of electrolyte, is a concern with sealed lead acid batteries, and overcharging contributes to this condition. While flooded systems accept water, a fill-up is not possible with VRLA. Adding water has been tried, but this does not offer a reliable fix. Experimenting with watering turns the VRLA into unreliable xps m1330 battery that needs high maintenance.
Flooded lead acid batteries are one of the most reliable systems. With good maintenance these batteries last up to 20 years. The disadvantages are the need for watering and providing good ventilation. When VRLA was introduced in the 1980s, manufacturers claimed similar life expectancy to flooded systems, and the telecom industry switched to these maintenance-free batteries,latitude d830 Battery ,inspiron 510m battery. By mid 1990 it became apparent that the life for VRLA did not replicate that of a flooded type; the useful service life was limited to only 5–10 years. It was furthermore noticed that exposing the batteries to temperatures above 40°C (104°F) could cause a thermal runaway condition due to dry-out.
A new lead acid battery should have an open circuit voltage of 2.125V/cell. At this time, the battery is fully charged. During buyer acceptance, the lead acid may drop to between 2.120V and 2.125V/cell. Shipping, dealer storage and installation will decrease the voltage further but the latitude d830 Battery ,inspiron 510m battery should never go much below 2.10V/cell. This would cause sulfation. Battery type, applying a charge or discharge within 24 hours before taking a voltage measurement, as well as temperature will affect the voltage reading. A lower temperature raises the OCV; warm ambient lowers it.
According to the 2010 BCI Failure Mode Study, starter batteries have become more heat-resistant over the past 10 years. In the 2000 study, a change of 7°C (12°F) affected battery life by roughly one year; in 2010 the heat tolerance has widened to 12°C (22°F). In 1962, a starter inspiron e1705 battery lasted 34 months, and in 2000 the life expectancy had increased to 41 months. In 2010, BCI reports an average age of 55 months of use. The cooler North attains 59 months and the warmer South 47 months.
Cranking the engine poses minimal stress on a starter battery. This changes in a start-stop function of a micro hybrid. The micro hybrid turns the IC engine off at a red traffic light and restarts it when the traffic flows. This results in about 2,000 micro cycles per year. Data obtained from car manufacturers show a capacity drop to about 60 percent after two years of use in this configuration. To solve the problem, automakers are using specialty AGM and other variations that are more robust than the regular lead acid. Read more about Alternate Battery Systems. Figure 5 shows the drop in capacity after 700 micro cycles. The simulated start-stop test was performed in Cadex laboratories. CCA remains high.
Test method: The test inspiron e1705 battery was fully charged and then discharged to 70 percent to resemble the SoC of a micro hybrid in real life. The battery was then discharged at 25A for 40 seconds to simulate engine off condition at stoplight with the headlight on, before cranking the engine at 400A and recharging. The CCA readings were taken with the Spectro CA-12.
The cell voltages on a battery string must be similar, and this is especially important for higher-voltage VRLA batteries. With time, individual cells fall out of line, and applying an equalizing charge every six months or so should theoretically bring the cells back to similar voltage levels. While equalizing will boost the needy cells, the healthy cell get stressed if the equalizing charge is applied carelessly. What makes this service so difficult is the inability to accurately measure the condition of each cell and provide the right dose of remedy. Gel and AGM batteries have lower overcharge acceptance than the flooded version and different equalizing conditions apply. Always refer to the manufacturer’s specifications.
Water permeation, or loss of electrolyte, is a concern with sealed lead acid batteries, and overcharging contributes to this condition. While flooded systems accept water, a fill-up is not possible with VRLA. Adding water has been tried, but this does not offer a reliable fix. Experimenting with watering turns the VRLA into unreliable xps m1330 battery that needs high maintenance.
Flooded lead acid batteries are one of the most reliable systems. With good maintenance these batteries last up to 20 years. The disadvantages are the need for watering and providing good ventilation. When VRLA was introduced in the 1980s, manufacturers claimed similar life expectancy to flooded systems, and the telecom industry switched to these maintenance-free batteries,latitude d830 Battery ,inspiron 510m battery. By mid 1990 it became apparent that the life for VRLA did not replicate that of a flooded type; the useful service life was limited to only 5–10 years. It was furthermore noticed that exposing the batteries to temperatures above 40°C (104°F) could cause a thermal runaway condition due to dry-out.
A new lead acid battery should have an open circuit voltage of 2.125V/cell. At this time, the battery is fully charged. During buyer acceptance, the lead acid may drop to between 2.120V and 2.125V/cell. Shipping, dealer storage and installation will decrease the voltage further but the latitude d830 Battery ,inspiron 510m battery should never go much below 2.10V/cell. This would cause sulfation. Battery type, applying a charge or discharge within 24 hours before taking a voltage measurement, as well as temperature will affect the voltage reading. A lower temperature raises the OCV; warm ambient lowers it.
2011年5月11日星期三
Dell XPS 15 L502X (Sandy Bridge) Review
When we last reviewed the Dell XPS 15, we praised the notebook's strong performance, best-in-class audio, and colorful screen. Now Dell has upgraded its premium 15-incher with Intel's second-generation Core Series processors and Nvidia GeForce GT 500 series graphics, which promise even better performance. We had a chance to test out a high-end $1,488 configuration of the XPS 15, complete with a 2-GHz quad-core Core i7, 8GB of RAM, a 1080p screen, and Nvidia GT540M graphics. These specs promise--and deliver--remarkable processing and media prowess, but is the whole package worth nearly $1,500?
The Dell XPS 15 sports a matte silver anodized aluminum lid that doesn't pick up fingerprints, but it seems a bit dull. Fortunately, Dell offers 200 different Dell Studio lid patterns (an $85 add-on). On the plus side, we appreciate the small black bar that sticks out behind the lid, which has a backlit XPS logo that pulses when the system is asleep. We also like that the matte finish continues on the sides and bottom, areas too often ignored by other notebook makers.
The dark brushed aluminum deck on the inside of the machine and the diamond-cut, silver trim that surround the keyboard and touchpad look more modern. The JBL speakers, which sit on either side of the keyboard, have a unique pattern that looks a bit old-fashioned.
At 15 x 10.4 x 1.5 inches and 6.6 pounds with the nine-cell battery, the XPS 15 is one of the bulkier 15-inch notebooks we've tested. It barely fit into a standard notebook bag, and it weighs a lot more than the 5.6-pound 15-inch MacBook Pro and the IdeaPad Y560d (6.2 pounds). Also, because the nine-cell battery tilts the system upward, the back side increases to 2.25 inches tall.
Throughout our testing, the Dell XPS 15 stayed pleasantly cool. Even after streaming a Hulu video at full screen for 15 minutes, we measured the touchpad at a reasonable 91 degrees Fahrenheit, the keyboard at 93 degrees, and the bottom at 93 degrees. We consider temperatures below 95 degrees comfortable.
At first glance, the XPS 15's keyboard has a lot going for it: an adjustable backlight, large, well-placed keys, and a generous, comfortable palm rest. However, the keys themselves were somewhat stiff. This led us to be more deliberate when typing. We notched a 74 word-per-minute score on the Ten Thumbs Typing Test, 6 wpm lower than our typical average.
Above the keyboard sit a few status lights and three touch-sensitive buttons. The first button launches Windows Mobility Center, a mini control panel that allows you to easily manage your Wi-Fi, Bluetooth, and display settings; we particularly appreciated being able to set the keyboard backlight's brightness. The second button is user-configurable, and the third button launches Dell Audio by Realtek, an audio control center.
The large 3.9 x 2.2-inch touchpad on the XPS 15 offers just the right amount of friction and smoothly executes multitouch gestures such as pinch-to-zoom. It also has two discrete mouse buttons that offer good tactile feedback.
The 15.6-inch, 1920 x 1080 resolution display on the XPS 15 is one of the brightest and most colorful we've tested. Even at viewing angles of nearly 90 degrees to the left or right, images stayed sharp and bright.
The XPS 15 played every video we threw at it without hesitation, from a 1080p QuickTime trailer for Thor to a 720p Episode of Fringe streamed from Fox.com to a Blu-ray movie of Hitch. The screen is so sharp that it exposed some film grain in the Hitch Blu-ray.
The XPS 15 is good enough to serve as your home stereo. The JBL Speakers and bottom-mounted sub-woofer offer incredibly loud and accurate sound. Whether we were listening to a bass-heavy song such as "Forget Me Nots," a funk classic such as Kool and the Gang's "Summer Madness," or a classical tune such as Richard Strauss' "Thus Spake Zarathustra," sound was bright and true, even at maximum volume. In fact, when listening to these songs we were able to hear a clear separation of instruments, from the twanging of the bass line in "Forget Me Nots" to the percussion in "Summer Madness."
The Wave MaxxAudio sound enhancement software plays a huge role in providing this level of fidelity. When you hit the Waves MaxxAudio button that sits above the PrtSrc key, you get a control panel where you can turn MaxxAudio on or off and make fine adjustments to its settings. The software also includes preset levels that are optimized for music, movies, gaming, or voice conferencing. However, our favorite feature is the Leveler, which automatically adjusts your speakers to give you the best possible fidelity at maximum volume, It also has a "midnight" setting that gives you lower volumes for late-night listening.
The Dell XPS 15 has a few high-end ports. On the right side are a headphone jack, a microphone jack, and an S/PDIF connector, along with a USB 2.0/eSATA combo port. On the back, the XPS 15 has an HDMI port, Ethernet, mini DisplayPort, Kensington lock slot, and a USB 3.0 port. On the left side is one more USB 3.0 port. The front lip contains a 9-in-1 card reader. The XPS 15 doesn't have a VGA connection for video output, but that's not a big deal for the target audience.
The 2-megapixel webcam provides 720p video output that works with Skype HD. The low-light performance seems improved over that of the XPS 15 we tested last fall. In both our dim living room and a dark cubicle, we were able to get reasonably bright images when using Skype or taking photos with Dell's Webcam Central software. Dell's software offers a wide array of additional features, including the ability to use one of 10 "avatars" in lieu of your face. These choices include a baby, a kitten, and an alien.
New laptop articles:
latitude d830 Battery ,inspiron 510m battery ,vostro 1700 battery ,latitude d630 battery ,solar radio emergency,
The Dell XPS 15 sports a matte silver anodized aluminum lid that doesn't pick up fingerprints, but it seems a bit dull. Fortunately, Dell offers 200 different Dell Studio lid patterns (an $85 add-on). On the plus side, we appreciate the small black bar that sticks out behind the lid, which has a backlit XPS logo that pulses when the system is asleep. We also like that the matte finish continues on the sides and bottom, areas too often ignored by other notebook makers.
The dark brushed aluminum deck on the inside of the machine and the diamond-cut, silver trim that surround the keyboard and touchpad look more modern. The JBL speakers, which sit on either side of the keyboard, have a unique pattern that looks a bit old-fashioned.
At 15 x 10.4 x 1.5 inches and 6.6 pounds with the nine-cell battery, the XPS 15 is one of the bulkier 15-inch notebooks we've tested. It barely fit into a standard notebook bag, and it weighs a lot more than the 5.6-pound 15-inch MacBook Pro and the IdeaPad Y560d (6.2 pounds). Also, because the nine-cell battery tilts the system upward, the back side increases to 2.25 inches tall.
Throughout our testing, the Dell XPS 15 stayed pleasantly cool. Even after streaming a Hulu video at full screen for 15 minutes, we measured the touchpad at a reasonable 91 degrees Fahrenheit, the keyboard at 93 degrees, and the bottom at 93 degrees. We consider temperatures below 95 degrees comfortable.
At first glance, the XPS 15's keyboard has a lot going for it: an adjustable backlight, large, well-placed keys, and a generous, comfortable palm rest. However, the keys themselves were somewhat stiff. This led us to be more deliberate when typing. We notched a 74 word-per-minute score on the Ten Thumbs Typing Test, 6 wpm lower than our typical average.
Above the keyboard sit a few status lights and three touch-sensitive buttons. The first button launches Windows Mobility Center, a mini control panel that allows you to easily manage your Wi-Fi, Bluetooth, and display settings; we particularly appreciated being able to set the keyboard backlight's brightness. The second button is user-configurable, and the third button launches Dell Audio by Realtek, an audio control center.
The large 3.9 x 2.2-inch touchpad on the XPS 15 offers just the right amount of friction and smoothly executes multitouch gestures such as pinch-to-zoom. It also has two discrete mouse buttons that offer good tactile feedback.
The 15.6-inch, 1920 x 1080 resolution display on the XPS 15 is one of the brightest and most colorful we've tested. Even at viewing angles of nearly 90 degrees to the left or right, images stayed sharp and bright.
The XPS 15 played every video we threw at it without hesitation, from a 1080p QuickTime trailer for Thor to a 720p Episode of Fringe streamed from Fox.com to a Blu-ray movie of Hitch. The screen is so sharp that it exposed some film grain in the Hitch Blu-ray.
The XPS 15 is good enough to serve as your home stereo. The JBL Speakers and bottom-mounted sub-woofer offer incredibly loud and accurate sound. Whether we were listening to a bass-heavy song such as "Forget Me Nots," a funk classic such as Kool and the Gang's "Summer Madness," or a classical tune such as Richard Strauss' "Thus Spake Zarathustra," sound was bright and true, even at maximum volume. In fact, when listening to these songs we were able to hear a clear separation of instruments, from the twanging of the bass line in "Forget Me Nots" to the percussion in "Summer Madness."
The Wave MaxxAudio sound enhancement software plays a huge role in providing this level of fidelity. When you hit the Waves MaxxAudio button that sits above the PrtSrc key, you get a control panel where you can turn MaxxAudio on or off and make fine adjustments to its settings. The software also includes preset levels that are optimized for music, movies, gaming, or voice conferencing. However, our favorite feature is the Leveler, which automatically adjusts your speakers to give you the best possible fidelity at maximum volume, It also has a "midnight" setting that gives you lower volumes for late-night listening.
The Dell XPS 15 has a few high-end ports. On the right side are a headphone jack, a microphone jack, and an S/PDIF connector, along with a USB 2.0/eSATA combo port. On the back, the XPS 15 has an HDMI port, Ethernet, mini DisplayPort, Kensington lock slot, and a USB 3.0 port. On the left side is one more USB 3.0 port. The front lip contains a 9-in-1 card reader. The XPS 15 doesn't have a VGA connection for video output, but that's not a big deal for the target audience.
The 2-megapixel webcam provides 720p video output that works with Skype HD. The low-light performance seems improved over that of the XPS 15 we tested last fall. In both our dim living room and a dark cubicle, we were able to get reasonably bright images when using Skype or taking photos with Dell's Webcam Central software. Dell's software offers a wide array of additional features, including the ability to use one of 10 "avatars" in lieu of your face. These choices include a baby, a kitten, and an alien.
New laptop articles:
latitude d830 Battery ,inspiron 510m battery ,vostro 1700 battery ,latitude d630 battery ,solar radio emergency,
2011年5月10日星期二
Dell XPS 15 L502X (Sandy Bridge) Review
When we last reviewed the Dell XPS 15, we praised the notebook's strong performance, best-in-class audio, and colorful screen. Now Dell has upgraded its premium 15-incher with Intel's second-generation Core Series processors and Nvidia GeForce GT 500 series graphics, which promise even better performance. We had a chance to test out a high-end $1,488 configuration of the XPS 15, complete with a 2-GHz quad-core Core i7, 8GB of RAM, a 1080p screen, and Nvidia GT540M graphics. These specs promise--and deliver--remarkable processing and media prowess, but is the whole package worth nearly $1,500?
The Dell XPS 15 sports a matte silver anodized aluminum lid that doesn't pick up fingerprints, but it seems a bit dull. Fortunately, Dell offers 200 different Dell Studio lid patterns (an $85 add-on). On the plus side, we appreciate the small black bar that sticks out behind the lid, which has a backlit XPS logo that pulses when the system is asleep. We also like that the matte finish continues on the sides and bottom, areas too often ignored by other notebook makers.
The dark brushed aluminum deck on the inside of the machine and the diamond-cut, silver trim that surround the keyboard and touchpad look more modern. The JBL speakers, which sit on either side of the keyboard, have a unique pattern that looks a bit old-fashioned.
At 15 x 10.4 x 1.5 inches and 6.6 pounds with the nine-cell battery, the XPS 15 is one of the bulkier 15-inch notebooks we've tested. It barely fit into a standard notebook bag, and it weighs a lot more than the 5.6-pound 15-inch MacBook Pro and the IdeaPad Y560d (6.2 pounds). Also, because the nine-cell battery tilts the system upward, the back side increases to 2.25 inches tall.
Throughout our testing, the Dell XPS 15 stayed pleasantly cool. Even after streaming a Hulu video at full screen for 15 minutes, we measured the touchpad at a reasonable 91 degrees Fahrenheit, the keyboard at 93 degrees, and the bottom at 93 degrees. We consider temperatures below 95 degrees comfortable.
At first glance, the XPS 15's keyboard has a lot going for it: an adjustable backlight, large, well-placed keys, and a generous, comfortable palm rest. However, the keys themselves were somewhat stiff. This led us to be more deliberate when typing. We notched a 74 word-per-minute score on the Ten Thumbs Typing Test, 6 wpm lower than our typical average.
Above the keyboard sit a few status lights and three touch-sensitive buttons. The first button launches Windows Mobility Center, a mini control panel that allows you to easily manage your Wi-Fi, Bluetooth, and display settings; we particularly appreciated being able to set the keyboard backlight's brightness. The second button is user-configurable, and the third button launches Dell Audio by Realtek, an audio control center.
The large 3.9 x 2.2-inch touchpad on the XPS 15 offers just the right amount of friction and smoothly executes multitouch gestures such as pinch-to-zoom. It also has two discrete mouse buttons that offer good tactile feedback.
The 15.6-inch, 1920 x 1080 resolution display on the XPS 15 is one of the brightest and most colorful we've tested. Even at viewing angles of nearly 90 degrees to the left or right, images stayed sharp and bright.
The XPS 15 played every video we threw at it without hesitation, from a 1080p QuickTime trailer for Thor to a 720p Episode of Fringe streamed from Fox.com to a Blu-ray movie of Hitch. The screen is so sharp that it exposed some film grain in the Hitch Blu-ray.
The XPS 15 is good enough to serve as your home stereo. The JBL Speakers and bottom-mounted sub-woofer offer incredibly loud and accurate sound. Whether we were listening to a bass-heavy song such as "Forget Me Nots," a funk classic such as Kool and the Gang's "Summer Madness," or a classical tune such as Richard Strauss' "Thus Spake Zarathustra," sound was bright and true, even at maximum volume. In fact, when listening to these songs we were able to hear a clear separation of instruments, from the twanging of the bass line in "Forget Me Nots" to the percussion in "Summer Madness."
The Wave MaxxAudio sound enhancement software plays a huge role in providing this level of fidelity. When you hit the Waves MaxxAudio button that sits above the PrtSrc key, you get a control panel where you can turn MaxxAudio on or off and make fine adjustments to its settings. The software also includes preset levels that are optimized for music, movies, gaming, or voice conferencing. However, our favorite feature is the Leveler, which automatically adjusts your speakers to give you the best possible fidelity at maximum volume, It also has a "midnight" setting that gives you lower volumes for late-night listening.
The Dell XPS 15 has a few high-end ports. On the right side are a headphone jack, a microphone jack, and an S/PDIF connector, along with a USB 2.0/eSATA combo port. On the back, the XPS 15 has an HDMI port, Ethernet, mini DisplayPort, Kensington lock slot, and a USB 3.0 port. On the left side is one more USB 3.0 port. The front lip contains a 9-in-1 card reader. The XPS 15 doesn't have a VGA connection for video output, but that's not a big deal for the target audience.
The 2-megapixel webcam provides 720p video output that works with Skype HD. The low-light performance seems improved over that of the XPS 15 we tested last fall. In both our dim living room and a dark cubicle, we were able to get reasonably bright images when using Skype or taking photos with Dell's Webcam Central software. Dell's software offers a wide array of additional features, including the ability to use one of 10 "avatars" in lieu of your face. These choices include a baby, a kitten, and an alien.
New laptop articles:
latitude d830 Battery ,inspiron 510m battery ,vostro 1700 battery ,latitude d630 battery ,solar radio emergency,
The Dell XPS 15 sports a matte silver anodized aluminum lid that doesn't pick up fingerprints, but it seems a bit dull. Fortunately, Dell offers 200 different Dell Studio lid patterns (an $85 add-on). On the plus side, we appreciate the small black bar that sticks out behind the lid, which has a backlit XPS logo that pulses when the system is asleep. We also like that the matte finish continues on the sides and bottom, areas too often ignored by other notebook makers.
The dark brushed aluminum deck on the inside of the machine and the diamond-cut, silver trim that surround the keyboard and touchpad look more modern. The JBL speakers, which sit on either side of the keyboard, have a unique pattern that looks a bit old-fashioned.
At 15 x 10.4 x 1.5 inches and 6.6 pounds with the nine-cell battery, the XPS 15 is one of the bulkier 15-inch notebooks we've tested. It barely fit into a standard notebook bag, and it weighs a lot more than the 5.6-pound 15-inch MacBook Pro and the IdeaPad Y560d (6.2 pounds). Also, because the nine-cell battery tilts the system upward, the back side increases to 2.25 inches tall.
Throughout our testing, the Dell XPS 15 stayed pleasantly cool. Even after streaming a Hulu video at full screen for 15 minutes, we measured the touchpad at a reasonable 91 degrees Fahrenheit, the keyboard at 93 degrees, and the bottom at 93 degrees. We consider temperatures below 95 degrees comfortable.
At first glance, the XPS 15's keyboard has a lot going for it: an adjustable backlight, large, well-placed keys, and a generous, comfortable palm rest. However, the keys themselves were somewhat stiff. This led us to be more deliberate when typing. We notched a 74 word-per-minute score on the Ten Thumbs Typing Test, 6 wpm lower than our typical average.
Above the keyboard sit a few status lights and three touch-sensitive buttons. The first button launches Windows Mobility Center, a mini control panel that allows you to easily manage your Wi-Fi, Bluetooth, and display settings; we particularly appreciated being able to set the keyboard backlight's brightness. The second button is user-configurable, and the third button launches Dell Audio by Realtek, an audio control center.
The large 3.9 x 2.2-inch touchpad on the XPS 15 offers just the right amount of friction and smoothly executes multitouch gestures such as pinch-to-zoom. It also has two discrete mouse buttons that offer good tactile feedback.
The 15.6-inch, 1920 x 1080 resolution display on the XPS 15 is one of the brightest and most colorful we've tested. Even at viewing angles of nearly 90 degrees to the left or right, images stayed sharp and bright.
The XPS 15 played every video we threw at it without hesitation, from a 1080p QuickTime trailer for Thor to a 720p Episode of Fringe streamed from Fox.com to a Blu-ray movie of Hitch. The screen is so sharp that it exposed some film grain in the Hitch Blu-ray.
The XPS 15 is good enough to serve as your home stereo. The JBL Speakers and bottom-mounted sub-woofer offer incredibly loud and accurate sound. Whether we were listening to a bass-heavy song such as "Forget Me Nots," a funk classic such as Kool and the Gang's "Summer Madness," or a classical tune such as Richard Strauss' "Thus Spake Zarathustra," sound was bright and true, even at maximum volume. In fact, when listening to these songs we were able to hear a clear separation of instruments, from the twanging of the bass line in "Forget Me Nots" to the percussion in "Summer Madness."
The Wave MaxxAudio sound enhancement software plays a huge role in providing this level of fidelity. When you hit the Waves MaxxAudio button that sits above the PrtSrc key, you get a control panel where you can turn MaxxAudio on or off and make fine adjustments to its settings. The software also includes preset levels that are optimized for music, movies, gaming, or voice conferencing. However, our favorite feature is the Leveler, which automatically adjusts your speakers to give you the best possible fidelity at maximum volume, It also has a "midnight" setting that gives you lower volumes for late-night listening.
The Dell XPS 15 has a few high-end ports. On the right side are a headphone jack, a microphone jack, and an S/PDIF connector, along with a USB 2.0/eSATA combo port. On the back, the XPS 15 has an HDMI port, Ethernet, mini DisplayPort, Kensington lock slot, and a USB 3.0 port. On the left side is one more USB 3.0 port. The front lip contains a 9-in-1 card reader. The XPS 15 doesn't have a VGA connection for video output, but that's not a big deal for the target audience.
The 2-megapixel webcam provides 720p video output that works with Skype HD. The low-light performance seems improved over that of the XPS 15 we tested last fall. In both our dim living room and a dark cubicle, we were able to get reasonably bright images when using Skype or taking photos with Dell's Webcam Central software. Dell's software offers a wide array of additional features, including the ability to use one of 10 "avatars" in lieu of your face. These choices include a baby, a kitten, and an alien.
New laptop articles:
latitude d830 Battery ,inspiron 510m battery ,vostro 1700 battery ,latitude d630 battery ,solar radio emergency,
2011年5月5日星期四
A Hidden Magnetic Effect
A dramatic and surprising magnetic effect of light discovered by University of Michigan researchers could lead to solar power(solar radio emergency) without traditional semiconductor-based solar cells.
The researchers found a way to make an "optical battery," said Stephen Rand, a professor in the departments of Electrical Engineering and Computer Science, Physics and Applied Physics.
In the process, they overturned a century-old tenet of physics.
"You could stare at the equations of motion all day and you will not see this possibility. We've all been taught that this doesn't happen," said Rand, an author of a paper on the work published in the Journal of Applied Physics. "It's a very odd interaction. That's why it's been overlooked for more than 100 years."
Light has electric and magnetic components. Until now, scientists thought the effects of the magnetic field were so weak that they could be ignored. What Rand and his colleagues found is that at the right intensity, when light is traveling through a material that does not conduct electricity,solar radio emergency , the light field can generate magnetic effects that are 100 million times stronger than previously expected. Under these circumstances, the magnetic effects develop strength equivalent to a strong electric effect.
"This could lead to a new kind of solar cell,solar radio emergency without semiconductors and without absorption to produce charge separation," Rand said. "In solar cells, the light goes into a material, gets absorbed and creates heat. Here, we expect to have a very low heat load. Instead of the light being absorbed, energy is stored in the magnetic moment. Intense magnetization can be induced by intense light and then it is ultimately capable of providing a capacitive power source."
What makes this possible is a previously undetected brand of "optical rectification," says William Fisher, a doctoral student in applied physics. In traditional optical rectification, light's electric field causes a charge separation, or a pulling apart of the positive and negative charges in a material. This sets up a voltage, similar to that in a battery. This electric effect had previously been detected only in crystalline materials that possessed a certain symmetry.
Rand and Fisher found that under the right circumstances and in other types of materials, the light's magnetic field can also create optical rectification,inspiron 510m battery.
"It turns out that the magnetic field starts curving the electrons into a C-shape and they move forward a little each time," Fisher said. "That C-shape of charge motion generates both an electric dipole and a magnetic dipole. If we can set up many of these in a row in a long fiber, we can make a huge voltage and by extracting that voltage, we can use it as a power source."
The light must be shone through a material that does not conduct electricity,inspiron 510m battery , such as glass. And it must be focused to an intensity of 10 million watts per square centimeter. Sunlight isn't this intense on its own, but new materials are being sought that would work at lower intensities, Fisher said.
"In our most recent paper, we show that incoherent light like sunlight is theoretically almost as effective in producing charge separation as laser light is," Fisher said.
This new technique could make solar power cheaper, the researchers say. They predict that with improved materials they could achieve 10 percent efficiency in converting solar power to useable energy. That's equivalent to today's commercial-grade solar cells.
"To manufacture modern solar cells,li-ion cell inspiron 510m battery,you have to do extensive semiconductor processing," Fisher said. "All we would need are lenses to focus the light and a fiber to guide it. Glass works for both. It's already made in bulk, and it doesn't require as much processing. Transparent ceramics might be even better."
In experiments this summer, the researchers will work on harnessing this power with laser light, and then with sunlight.
The paper is titled "Optically-induced charge separation and terahertz emission in unbiased dielectrics." The university is pursuing patent protection for the intellectual property.
The researchers found a way to make an "optical battery," said Stephen Rand, a professor in the departments of Electrical Engineering and Computer Science, Physics and Applied Physics.
In the process, they overturned a century-old tenet of physics.
"You could stare at the equations of motion all day and you will not see this possibility. We've all been taught that this doesn't happen," said Rand, an author of a paper on the work published in the Journal of Applied Physics. "It's a very odd interaction. That's why it's been overlooked for more than 100 years."
Light has electric and magnetic components. Until now, scientists thought the effects of the magnetic field were so weak that they could be ignored. What Rand and his colleagues found is that at the right intensity, when light is traveling through a material that does not conduct electricity,solar radio emergency , the light field can generate magnetic effects that are 100 million times stronger than previously expected. Under these circumstances, the magnetic effects develop strength equivalent to a strong electric effect.
"This could lead to a new kind of solar cell,solar radio emergency without semiconductors and without absorption to produce charge separation," Rand said. "In solar cells, the light goes into a material, gets absorbed and creates heat. Here, we expect to have a very low heat load. Instead of the light being absorbed, energy is stored in the magnetic moment. Intense magnetization can be induced by intense light and then it is ultimately capable of providing a capacitive power source."
What makes this possible is a previously undetected brand of "optical rectification," says William Fisher, a doctoral student in applied physics. In traditional optical rectification, light's electric field causes a charge separation, or a pulling apart of the positive and negative charges in a material. This sets up a voltage, similar to that in a battery. This electric effect had previously been detected only in crystalline materials that possessed a certain symmetry.
Rand and Fisher found that under the right circumstances and in other types of materials, the light's magnetic field can also create optical rectification,inspiron 510m battery.
"It turns out that the magnetic field starts curving the electrons into a C-shape and they move forward a little each time," Fisher said. "That C-shape of charge motion generates both an electric dipole and a magnetic dipole. If we can set up many of these in a row in a long fiber, we can make a huge voltage and by extracting that voltage, we can use it as a power source."
The light must be shone through a material that does not conduct electricity,inspiron 510m battery , such as glass. And it must be focused to an intensity of 10 million watts per square centimeter. Sunlight isn't this intense on its own, but new materials are being sought that would work at lower intensities, Fisher said.
"In our most recent paper, we show that incoherent light like sunlight is theoretically almost as effective in producing charge separation as laser light is," Fisher said.
This new technique could make solar power cheaper, the researchers say. They predict that with improved materials they could achieve 10 percent efficiency in converting solar power to useable energy. That's equivalent to today's commercial-grade solar cells.
"To manufacture modern solar cells,li-ion cell inspiron 510m battery,you have to do extensive semiconductor processing," Fisher said. "All we would need are lenses to focus the light and a fiber to guide it. Glass works for both. It's already made in bulk, and it doesn't require as much processing. Transparent ceramics might be even better."
In experiments this summer, the researchers will work on harnessing this power with laser light, and then with sunlight.
The paper is titled "Optically-induced charge separation and terahertz emission in unbiased dielectrics." The university is pursuing patent protection for the intellectual property.
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