Below are the most recent 6 friends' journal entries.

Friday, November 20th, 2009
suppliercn	11:03a	Cylindrical roller bearings Cylindrical roller bearings usually by a wall bearing rings of the two lead, Cage, and guide roller rings composed of a combination of things, the general type of bearing is detachable. Bearing this installation, the demolition of more convenient, especially when requested, and the outer shell and shaft are fit more shows its advantages. Bearing this kind generally used for radial load to bear, only, the outer wall with all the separate bearings can withstand axial loading smaller or larger batch of axial load. The same size and shape of the deep groove ball bearings, bearing with such a large radial load capacity of the structure from the point of view, also applies to high-speed rotation. (Comment on this)
suppliercn	11:02a	Ball bearings A ball bearing is a type of rolling-element bearing which uses balls to maintain the separation between the moving parts of the bearing. The purpose of a ball bearing is to reduce rotational friction and support radial and axial loads. It achieves this by using at least two races to contain the balls and transmit the loads through the balls. Usually one of the races is held fixed. As one of the bearing races rotates it causes the balls to rotate as well. Because the balls are rolling they have a much lower coefficient of friction than if two flat surfaces were rotating on each other. Ball bearings tend to have lower load capacity for their size than other kinds of rolling-element bearings due to the smaller contact area between the balls and races. However, they can tolerate some misalignment of the inner and outer races. Compared to other bearing types, the ball bearing is the least expensive, primarily because of the low cost of producing the balls used in the bearing. There are several common designs of ball bearing, each offering various tradeoffs. They can be made from many different materials, including: stainless steel, chrome steel, and ceramic (silicon nitride (Si3N4)). A hybrid ball bearing is a bearing with ceramic balls and races of metal. (Comment on this)
suppliercn	11:02a	Deep Groove Ball Bearing Deep Groove Ball Bearings are the most popular of all the ball bearing types because they are available in a wide variety of seal, shield and snap-ring arrangements. The bearing ring grooves are circular arcs made slightly larger than the radius of the ball. The balls make point contact with the raceways (elliptical contact when loaded). The inner ring shoulders are of equal height (as the outer ring shoulders). Deep Groove ball bearings can sustain radial, axial, or composite loads and because of simple design, this bearing type can be produced to provide both high-running accuracy and high-speed operation. Consequently, they are available in many executions and sizes. Deep groove ball bearing have various types in structure, beside open type bearings, shield or seals at both side can also be provided Deep groove ball bearings are non-separable and require little attention or maintenance in service, capable of operating at high speeds and are widely used radial bearings. The inner and outer ring of single row deep groove ball bearings have a deep groove raceway, the bearings are mainly used to carry radial loads and a part of axial loads in two directions. This kind of bearing can carry much heavy axial loads after the increase of radial clearance, thus, it can take the place of high speed angular contact ball bearings. (Comment on this)
suppliercn	11:01a	Tapered roller bearing description The inner and outer ring raceways are segments of cones and the rollers are also made with a taper so that the conical surfaces of the raceways and the roller axes if projected, would all meet at a common point on the main axis of the bearing. This conical geometry is used as it gives a larger contact patch, which permits greater loads to be carried than with spherical (ball) bearings, while the geometry means that the tangential speeds of the surfaces of each of the rollers are the same as their raceways along the whole length of the contact patch and no differential scrubbing occurs. This avoids rapid wear and greatly reduces rolling friction. The rollers are guided by a flange on the inner ring. This stops the rollers from sliding out at high speed due to their momentum. The larger the half angles of these cones the larger the axial force that the bearing can sustain. Tapered roller bearings are separable and have the following components: outer ring, inner ring, and roller assembly (containing the rollers and a cage). The non-separable inner ring and roller assembly is called the cone, and the outer ring is called the cup. Internal clearance is established during mounting by the axial position of the cone relative to the cup. (Comment on this)
Thursday, November 19th, 2009
suppliercn	9:38a	LED lamp that runs on free power If you’re a real tight-wad, here’s an LED lamp that will make you smile. It’s an LED lamp that is powered by your phone line. If you’re scratching your head in confusion, you must not know that phone lines carry a low level of electricity. That’s why you’re analog phones work even when the power goes out. This 8 LED lamp takes advantage of that fact by including an RJ11 plug that you can connect to any standard phone jack. (Comment on this)
suppliercn	9:31a	LED Lamp will be the future of lamp LEDs are solid-state semiconductor devices that convert electrical energy directly into light. Thermal sources of light such as flames and incandescent filaments emit light when heated, either by chemical reaction (flames) or electrical heating (filament lamps). LED "cold" generation of light leads to high efficacy because most of the energy radiates within the visible spectrum. Other common high efficiency light sources, such as fluorescent lamps and electro luminescent devices, also produce light without much thermal radiation outside the visible spectrum. Because LEDs are solid-state devices, they can be extremely small and durable; they also provide longer lamp life than other sources. Light is generated inside the chip, a solid crystal material, when current flows across the junctions of different material compositions. An LED consists of two elements of processed material called P-type semiconductors and N-type semiconductors. These two elements are placed in direct contact, forming a region called the P-N junction. The composition of the different materials determines the wavelength and therefore the colour of light generated LED resembles most other diode types, but there are important differences. The LED has a transparent package, allowing visible or IR energy to pass through. Also, the LED has a large PN-junction area whose shape is tailored to the application. The device shown in Figure 1 is an AlGaInP LED because the semiconductor layers are aluminum (Al), gallium (Ga), indium (In), and phosphate (P). Main LED materials The main semiconductor materials used to manufacture LEDs are: *Indium gallium nitride (InGaN): blue, green and ultraviolet high-brightness LEDs *Aluminum gallium indium phosphide (AlGaInP): yellow, orange and red high-brightness LEDs *Aluminum gallium arsenide (AlGaAs): red and infrared LEDs *Gallium phosphide (GaP): yellow and green LEDs (Comment on this)