Characteristics of the LED light source

Voltage

LED low voltage power supply, power supply voltage between 6-24V, depending on the product, so it is safer than the use of high-voltage power supply power supply, particularly in public places.

Efficacy

Energy consumption reduced by 80% than the same luminous efficiency of incandescent

Applicability

Very small, small piece of each unit LED is 3-5mm square, so the device can be fabricated into various shapes, and is suitable for the environment variable

Light-emitting diodes

Stability

100,000 hours, the light fades to 50% of the initial

Response time

Incandescent response time of milliseconds, the response time of the LED lights for a nanosecond

Of environmental pollution

No harmful metallic mercury

Color

Materials of light-emitting diodes by chemical modification methods, adjusting the energy band structure and band gap, red yellow blue orange multicolor light. Red tube voltage is small, different colors of red, orange, yellow, green, and blue light-emitting diode operating voltage is increased successively.

Price

LED price is now more and more civilians, due to the LED power-saving features, perhaps in the near future, people are the incandescent LED lights. Now, some cities in our country roads, schools, factory and other places have switched to the the Wan LED street light, energy-saving lamps.

Monochromatic LED types and history of the development

The LED light source made of the earliest applications of semiconductor PN junction light-emitting principle is introduced in the early 1960s. Use at the time material is GaAsP, red (λp = 650nm), the drive current of 20 mA, the luminous flux is only thousandths of a few lumens, luminous efficiency of about 0.1 lm / W

The mid-1970s, the introduction of elements of In and N, generated by the LED green (λp = 555nm), yellow (λp = 590nm) and orange (λp = 610nm), luminous efficiency is also increased to a lumens / watt.

To the early 1980s, there has been a GaAlAs LED light source, the red LED luminous efficiency of 10 lumens / watt.

The early 1990s, of red, yellow the GaAlInP and green, blue GaInN two new materials successfully developed, so that the LED luminous efficiency has been greatly improved. In 2000, the former is made of LED in red, orange District (λp = 615nm) light efficiency of 100 lm / W, while the latter is made of LED luminous efficiency in the green region (λ p = 530nm) can reach 50 lm / watts.

Monochromatic LED applications

Light-emitting diodes

The initial LED as the light of the instructions of the instrumentation, then a variety of light-colored LEDs in traffic lights and a large area display a wide range of applications, resulting in a good economic and social benefits. To 12 inches of red traffic lights, for example, in the United States was long-lived, low-efficiency 140-watt incandescent lamp as a light source, it produces 2000 lumens of white light. The red filter, the light loss of 90%, leaving only 200 lumens of red light. In the light of the new design, Lumileds uses 18 red LED light source, including circuit losses, the total power consumption of 14 watts to produce the same luminous efficiency.

The car lights are also an important area of ​​the LED light source applications. 1987, China began to be installed in the car CHMSL LED response speed (nanosecond), an early stage so that the trailing vehicle drivers know that driving conditions to reduce rear-end accidents.

In addition, LED lights in the outdoor red, green, blue full-color display, mini flashlight key chain field have been applied.

Resourse from electronics store

about purchase of recording equipment

With more and more types of digital products with recording function, the quality is getting better and better, cheaper and cheaper, carry a small digital recording lectures, participate in training, not only in the students' family, more and more popular, has become the business people who prepare for graduate school, to participate in foreign language learning, and often have a variety of business training needs to participate in the new choice. However, currently on the market a variety of both with a recording function, MP3, there are a lot of professional voice recorder in the recording function in the end what difference does it make? For lectures, training, recording, and is more suitable to choose a more entertainment features eye-catching MP3 is a more professional voice recorder products?

MP3 voice recorder from the same root

We first figure out what can be recorded MP3, what is the voice recorder. Part of the MP3 player to listen to the reason why can record, because the main chip comes with a variety of functions, recording just one auxiliary function, of course, even if the MP3 recording the main direction of the streaming audio file decoding. So-called "Wen Tao has the industry specializing in surgery", the voice recorder's own work is based on the "recording" for the general direction of the digital products, they are generally equipped with professional sound processing chip than MP3 higher sensitivity, greater microphone. also pay more attention to sound real and natural reduction.

Recording MP3 player to open is generally used in the menu mode of entry, need to go through 3-4 steps menu click actions in order to start recording, to cope with the unexpected recording becomes more passive, another operation is also some tedious. Normal MP3 players in general, only a built-in MIC, and no voice recorder's ability to identify, do not have the sound track, steering and other professional functions, and recording the results are unsatisfactory, in order to be competent external recording, voice recording, static tone function built-in speakers, the sound sensor recording the more specialized requirements, for the MP3 recording function is a bit difficult. We see that the voice recorder is commonly used one-touch button design, simple touch to open the recording, but also ready to open the recording function is very convenient in other tasks. Professional voice recorder also provides a sound track, noise reduction function, these results for the final recording quality is essential, environmental noise acoustic interference is very clear for us to collect information. The voice recorder is far better than MP3 sound collection point of view.

The special features on the design of the recording pen is very human, usually have a timer recording, automatic recording based on user preset time, in response to certain special occasions such as meetings, programs, recordings, etc. are very useful. For regular MP3 users (assuming the student class recording), a few classes a day off, the recording file is a time for hours of audio files, if you want to listen to the contents of a lesson we must start to finish will This file playback again, to find where it is needed, but next time you want to listen to the paragraph, and in turn to repeat this work. This process for the students of valuable learning time is too complicated. Some of the voice recorder for recording file can be based on continuous recording time of partition, such as the Patriot F198 (Figure) with automatic segmentation. According to class length every 30/60/90 minutes of audio content is independent of segment generated file, so the review after class, they can quickly find what you need a paragraph, is very convenient, and this is particularly suitable for classroom recording one of the places. While recording for ordinary MP3 is a special function, with the timing function is a bit far-fetched. If reporters interview was suggested to buy a professional voice recorder for students in terms of very frequent use recording MP3 recording was in trouble. MP3 and voice recorder, MP3 files versatility to win special functions or voice recorder came out on top.

There is a reasonable positioning before the best buy on their own, if it is to meet the needs of training and learning, Xiaobian recommend or buy a more professional voice recorder products; If you primarily to the entertainment needs of life demand is not very high on the recording, can record MP3 may well be an ideal choice.

about knowledge of car care products

Car care according to the different parts of the car care, into the internal care and external care.

Car care automotive interior parts of machines, such as cleaning and maintenance, Car care product classification antifreeze, coolant, brake fluid, lubricants, additives and so on, the engine and other protective effects.

Outside of the car care, also known as car beauty, pay more attention to the protection of automotive paint finish protection car appearance to maintain beautiful, such as car wax, seal the glaze, coating products.

1, car wax

(1), decontamination wax decontamination polishing liquid wax

Features: decontamination, rust, scale and bright function to restore the bright color of the paint and metal.

How to use: smear the surface of dirty utensils.

Scope of application: automotive body.

Note: Do not use in the body is warm.

(2), light wax

Features: bright durable, quality and stability (includes colorful agent). Form a protective film to prevent oxidation, acid rain erosion, so that the paint non-stick dust in the finish.

Use: Apply the body surface. Dirt, such as paint adhesion with descaling of "decontamination December", and then smear this product.

Scope of application: automobile body and a variety of metal products.

Note: Do not use in the body is warm.

(3), the protective wax

Features: remove oil, tar, to prevent rust, can produce stable, water-resistant protective film.

Use: Wash the car and dry before use, shake the jar, uniform spray parts can be in need of protection.

Scope: the car's surface and groove.

Note: Do not use tung oil-based paint surface.

(4), mirror wax

Features: a high-performance care natural wax containing carnauba and polycarbonate. Paint penetration strong, shiny as a mirror, maintain long-lasting, effective care and car paint.

Use: Apply body paint by hand to find the wax and machine waxing can be.

Scope: suitable for a new car and used car polishing refurbished paint care.

(5), anti-static wax

Features: a spray polish care wax, to prevent the paint static electricity to minimize the electrostatic adsorption of dust, oil.

Usage: Apply in body paint.

Scope of application: car paint, leather, plastic and chrome surface treatments.

(6), colored wax

Characteristics: divided into red, blue, green, gray and black colors, the fight that is polished, saving time and effort. The different colors of cars using the corresponding color of wax, to play a modified role of the paint can mask minor small scratches.

Use: Apply the body surface.

Scope: applies a variety of car paint

(7), the chassis protective wax

Features: paint, rubber, plastic and PVC paint. Long to prevent the chassis corrosion and the rattle of gravel. Can prevent the change of surface color, the effect of noise antirust.

Method of use: before chassis wash, brush the rust and the steel and spray until completely clean and free from rust. Before use, shake the jar, so that the internal chemical agent fully mixed. 294785kPa compressed air is required to use.

Note: This product is combustible. Use should pay attention to the protection of the eyes, skin and respiratory system. Do not spray in the exhaust, brakes, and the reduction in vibration spring, to be used with alcohol dilution.

2, cleaning agents

(1), with detergent

Features: remove the dirt of all kinds of glass, paint and metal products, does not harm paint, plastic and rubber. Foam cleaner, trickle trouble.

How to use: spray in the dirty surface of the apparatus, so that the bubble stay 1min, and wipe with a clean cotton cloth.

Scope of application: automotive windshield and wind windowpane.

Note: Do not wait for foam all dry before hands to wipe.

(2), brake cleaners

Characteristics: the rapid removal of dirt, to avoid jarring noise, does not contain toxic substances will not cause environmental pollution.

Usage: Ba is applied to the dirty parts of the surface, so dirt drops to make a dry cloth.

Scope: drum and disc brakes, brake pads, brake components, clutch plate, fan belt, the pressure components.

Note: combustible, and attention to fire safety when used.

(3), the car dashboard cleaners.

Characteristics: to maintain the luster of artificial leather and leather of the car, so that dust can not be soiled. Lemon flavor, silicon-Li Kang, will not damage paint, also known as synthetic rubber, plastic polishes.

Use: Spray the surface and gently wipe with a soft cloth.

Scope: mainly applied to the door of plastic material, leather products, such as: leather, bags, instrument panels, interior synthetic rubber and plastics, etc..

Note: flammable, non-spraying in the driver's steering wheel, seat support at.

(4), the engine exterior cleaners.

Features: remove heavy oil pollution. Alkaline, containing corrosion inhibitor composition, rapid emulsion decomposition to remove the oil, without corrosion of the body and its parts. Water-soluble, and can be completely dissolved, easy to wash with water, leaving no residue.

Usage: diluted with water sprayed on the part appearance and oil at, with the amount of water rinse, wipe with a soft cloth.

Scope: applies to the engine appearance chassis and other parts

Note: alkaline, to be diluted with water before use.

(5), engine cleaners

Features: remove grease dirt, waste oil and useless acidic compounds.

Usage: used in the engine turns off after cooling. Spray mouthpiece osmotic 2min after washing with tap water into the engine and its surrounding it completely. Dry and then spray the engine paint protection agents to clean. Wash after completion, such as the engine can not start due to damp, use the "super" for processing.

Scope: engine external

(6), valve and carburetor cleaners.

Features: remove accumulated in the carburetor, valve and valve seat coke and dirt, enhance the smooth flow of the engine air intake, to avoid unnecessary power consumption, recovery cylinder of the original compression ratio, reducing the generation of CO

Usage: Add this product before refueling, add 1%.

Scope of application: All car engine and carburetor-type internal combustion engine.

Note: flammable, but not lead, cadmium, PCBs, alcohol and other harmful compounds will not cause environmental pollution.

(7), tank rust cleaners

Characteristics: removal of the tank fouling, rust stains, mud deposition reach rust, clean results. Rust cleaners in a can of 150mL diluted approximately 12L of water.

Method of use: the front to make the water tank. Then injected into the water and the product. Let the engine idle 20min, the discharge water tank into the water should be added to the water tank thermostat leak agent.

(8), wheel cleaners

Characteristics: effective removal of grease on the wheels, oxidation stains and clean coating. This product is a weak acid, but no corrosion on the wheels and tires.

How to use: spray cleaner in addition to the car wheels, with a soft cloth.

The scope of application: All car wheels.

(9), all purpose cleaners, fabric softener

Features: various parts of the room and luggage car cleaning renovation. Strong detergency, in particular, can play on the velvet and carpet surface clean, supple, restore, such as coloring and sterilization efficacy.

How to use: spray pumping machine or hand spray the amount of cleaning agent to the need to be cleaned parts and cleaning parts with a dry cloth to clean.

(10), heavy cleaning agent

Features: a powerful emulsifiable solvent-based heavy oil cleaning agent, can effectively remove the heavy oil on the car engine parts and equipment, and equipment. This product contains a special ingredient can make dirt curling into the micelles, micellar particles fast separation of the adhesive material is easily cleaned with water, does not produce secondary pollution. Can absorb six times its volume of oil pollution, it can be reused, the corrosive effect of the various parts of the body.

Usage: This product will be sprayed on the oil spill at the micelles formed by water flush and then dried with a cloth.

Application: Mainly used in the bottom of the car engine parts and chassis.

3, the polishing agent

(1), a strong polish

Characteristics: This product is a new type of abrasive material containing particles finer than ordinary abrasive. Can remove the paint thicker oxide layer, scratches and paint, "pitting" and "sag", silicon and wax.

Usage: Apply evenly on the car finish (polishing machine)

Note: before a small test with the use of polishing machine.

(2), paint to restore the polishing agent reductant

Characteristics: This product is finer than the strong polish, abrasive particles, can remove the paint moderate oxide and mild scratches. More secure not silicon and wax job in a small venue, beauty shop, automotive paint refurbished supplies. This product is oil-bearing points penetrate the paint and supplementary paint oil lost in the finish polishing at the same time, play a brightening care role.

How to use: with the polishing machine is applied in the automotive paint.

Scope of application: automotive paint.

(3), fast polish

Characteristics: This product is finer than the moderate the polishing dose of abrasive particles, with the removal of the double effect of minor oxide and waxing treatments. As polishing the final process can be used by hand, make up the machine polishing uneven, resulting in the phenomenon of halo, etc., brightening effect, also known as a brightening agent.

How to use: hand evenly spread in the car paint.

(4), glass polishing agent

Features: remove the sticky dyed glass on the surface of tar, grease, dead insects, stains, and black oxide layer is difficult cleansed of dirt.

Scope: windshield, mirrors and other parts.

(5), multi-function polish

Features: remove the hard surface of the metal plating surface and glass black oxide layer and restore the original luster, and the formation of a very light layer of protective film. Also be used in car paint.

Scope: all types of metal plating surface, glass and other hard surfaces and car paint.

about beauty-you like it

Beauty is a characteristic of a person, animal, place, object, or idea that provides a perceptual experience of pleasure or satisfaction.[1] Beauty is studied as part of aesthetics, sociology, social psychology, and culture. An "ideal beauty" is an entity which is admired, or possesses features widely attributed to beauty in a particular culture, for perfection.


There is evidence that perceptions of beauty are evolutionarily determined, that things, aspects of people and landscapes considered beautiful are typically found in situations likely to give enhanced survival of the perceiving human's genes.

The experience of "beauty" often involves the interpretation of some entity as being in balance and harmony with nature, which may lead to feelings of attraction and emotional well-being.[citation needed] Because this is a subjective experience, it is often said that "beauty is in the eye of the beholder."

USB flash drive of Advantages and disadvantages

Advantages：

Compared to hard drives, flash drives use little power, have no fragile moving parts, and for most capacities are small and light. Data stored on flash drives is impervious to mechanical shock, magnetic fields, scratches and dust. These properties make them suitable for transporting data from place to place and keeping the data readily at hand.

Flash drives also store data densely compared to many removable media. In mid-2009, 256 GB drives became available, with the ability to hold many times more data than a DVD or even a Blu-ray disc,

Most personal computers support USB as of 2010. Flash drives implement the USB mass storage device class so that most modern operating systems can read and write to them without installing device drivers. The flash drives present a simple block-structured logical unit to the host operating system, hiding the individual complex implementation details of the various underlying flash memory devices. The operating system can use any file system or block addressing scheme. Some computers can boot up from flash drives.

Specially manufactured flash drives are available that have a tough rubber or metal casing designed to be waterproof and virtually "unbreakable". These flash drives retain their memory after being submerged in water, and even through a machine wash. Leaving such a flash drive out to dry completely before allowing current to run through it has been known to result in a working drive with no future problems. Channel Five's Gadget Show cooked one of these flash drives with propane, froze it with dry ice, submerged it in various acidic liquids, ran over it with a jeep and fired it against a wall with a mortar. A company specializing in recovering lost data from computer drives managed to recover all the data on the drive. All data on the other removable storage devices tested, using optical or magnetic technologies, were destroyed.

Disadvantages：

Like all flash memory devices, flash drives can sustain only a limited number of write and erase cycles before the drive fails. unreliable source? This should be a consideration when using a flash drive to run application software or an operating system. To address this, as well as space limitations, some developers have produced special versions of operating systems (such as Linux in Live USB) or commonplace applications (such as Mozilla Firefox) designed to run from flash drives. These are typically optimized for size and configured to place temporary or intermediate files in the computer's main RAM rather than store them temporarily on the flash drive.

Most USB flash drives no longer include a write-protect mechanism, although a small number have a switch on the housing of the drive itself to keep the host computer from writing or modifying data on the drive. Write-protection makes a device suitable for repairing virus-contaminated host computers without risk of infecting the USB flash drive itself. A write-locked SD card in a USB flash card reader adapter is an effective way to avoid any writes on the flash medium. The SD card as a WORM device has an essentially unlimited life.

A drawback to the small size is that they are easily misplaced, left behind, or otherwise lost. This is a particular problem if the data they contain are sensitive (see data security). As a consequence, some manufacturers have added encryption hardware to their drives—although software encryption systems which can be used in conjunction with any mass storage medium achieve the same thing. Most drives can be attached to keychains, necklaces and lanyards. The USB plug is usually fitted with a removable and easily lost protective cap, or is retractable.

USB flash drives are more expensive per unit of storage than large hard drives, but are less expensive in capacities of a few tens of gigabytes as of 2011. Maximum available capacity is increasing with time, but is less than larger hard drives. This balance is changing, but the rate of change is slowing.