Metal commodities HS code directory

List of contents of this article:

• 1,Metal commodities HS code directory May I ask what is the prism of the positive image of the Kepler telescope?
• 2, Which is the top ten domestic system door and window brands
• 3, What is the difference between Paul and ridge telescopes? Just these two?
• 4, Is the prism system of the telescope better, Paul or the ridge? Why?
• 5, Which brand of system doors and windows is of good quality

May I ask what is the prism of the positive image of the Kepler telescope?

The Kepler binoscope generally relies on the image prism to obtain the positive image. The following two commonly used types: PorroPrism is the most commonly used prism. The binocular of the proprism is wider, and the spacing between the two objective lenses is larger than the spacing of the eyepiece, so that the three-dimensional sense is strong when observing nearby objects.

Kepler telescope, a kind of refractive telescope. The objective lens group is also in the form of a convex lens, but the eyepiece group is in the form of a convex lens. This kind of telescope imaging is inverted up and down, but the field of view can be designed to be larger. It was first invented by German scientist Johannes Kepler in 1611.

Common telescopes are Kepler structures, and their eyepieces are generally convex lenses or lens groups. Because there are real images in their optical paths, ranging or aiming splicing plates can be installed to measure distances.

Because the telescope is not a group of optical lenses consisting only of a convex lens and a concave lens, which presents an inversion. Telescopes in real life are composed of multiple lenses and reflective prisms. The principle of the telescope: It is composed of two sets of convex lenses, the objective lens and the eyepiece. The focal length of the objective lens is long, while the focal length of the eyepiece is short.

There are three types of orthoginal telescopes in the current market.

The basic principle of the Kepler telescope is that first the distant light enters the convex lens of the objective lens, and the first time it becomes an inverted and reduced real image, which is equivalent to a camera; then the real image enters the convex lens of the eyepiece, and the second time it becomes a vertical and magnified virtual image, which is equivalent to a magnifying glass.

Which are the top ten brands of internal system doors and windows?

I: Belima doors and windows. Founded in 2000, Belima doors and windows are one of the top ten brands of complete doors and windows, system doors and windows. It mainly produces high-end system doors and windows, aluminum alloy doors and windows, sunroom customization, etc. The products are mainly light luxury series, and the country has 500 + Brand specialty stores are deeply loved and recognized by consumers and franchisees.

The top ten domestic system door and window brands are BLM BLM, as one of the leading brands of high-end doors and windows, is one of the top ten brands of doors and windows with high popularity and rich production experience.

This article will recommend the top ten system door and window brands to you, including Belima doors and windows, Mercer doors and windows, Xuge doors and windows, Ouzhe doors and windows, YKK doors and windows, Huangpai doors and windows, Paiya doors and windows, Xinhaoxuan doors and windows, Beckluo doors and windows, and Senying doors and windows.

The top ten brands of system doors and windows are on the list: Xuge doors and windows, YKK doors and windows, WICONA doors and windows, Senying doors and windows, Mercer doors and windows, Ozhe doors and windows, Huangpai doors and windows, Belima doors and windows, Xiluo doors and windows, Becklo doors and windows, etc. Xuge Doors and Windows Xuge Doors and Windows adopts advanced production technology to ensure the precision and consistency of the product.

Skate Doors and Windows was established in 1997. It is the first batch to enter the door and window industry. It has leading technology and status. The product quality has reached the top level in the industry. With the advantage of high cost-effectiveness, it has quickly occupied more than half of the market share. It is a highly recommended top ten brands.

What is the difference between Paul and ridge telescopes? Just these two?

1. The Paul telescope (Porro) and the roof telescope (Roof) are the two most commonly used telescope structures at present. The difference is that the prism structures used are different.

2. The difference between the shape of the telescope using the roof ridge and the proprism is very obvious. The more significant difference is the shape of the roof ridge telescope.Because it is a straight tube, it is also often called a straight-tube telescope, while the Pro telescope bends at the prism position, so the volume is much larger than the ridge telescope of the same specification.

3. In the middle and low-end telescopes, the Paul mirror is more cost-effective in terms of optics, but in the high-end telescope, most of them are the world of roof mirrors. Because the Paul telescope is cheap, and the brightness and contrast can be relatively satisfactory at no cost.

4. It can't achieve full reflection, it needs to be coated, and the human eye is so wide). It can be made small, but not big. The maximum caliber is 63. The easiest way to distinguish is to look at the shape. The ridge telescope is straight, and the objective lens and eyepiece are in a straight line. The objective lens and eyepiece of the Paul telescope are not in a straight line.

5. Disadvantages: Paul-style telescopes have poor sense of realism, including the size and distance of the target are not as good as the ridge-style. Another important point is that the sense of body vision and operation are not good. And this is determined by the structure and cannot be changed through other adjustments. Therefore, most of the high-end telescopes among the famous brands are ridge-type structures.

6. Ordinary handheld telescopes (non-astronomical telescopes) can be roughly divided into two categories: ridge type and Paul type. Paul's style is mainly that his reflective lens group consists of two right-angled prisms (or right-angled).

Is the prism system of the telescope better, Paul or the ridge? Why?

1. In the middle and low-end telescope,Paul mirrors are more cost-effective in terms of optics, and in high-end telescopes, most of them are the world of roof mirrors. Because the Paul telescope is cheap, and the brightness and contrast can be relatively satisfactory at no cost.

2. Advantages: The PORRO Paul type will have brighter imaging than the ROOF ridge telescope of the same grade, and the contrast or image is harder. Disadvantages: Paul-style telescopes have poor realism, including the size and distance of the target are not as good as the ridge-style. Another important point is that the body vision and operation are not good.

3. Military telescopes do not use ridge mirrors because the cost of ridge mirrors is high. All I have seen are Paul mirrors, not only because they are simple and durable, but also because the cost of Paul telescopes is low, and the brightness and contrast can be relatively satisfactory without too much cost.

Which brand of system doors and windows is of good quality

Meizhen doors and windows Meizhishen doors and windows is one of the top ten brands of aluminum alloy doors and windows, specializing in the production of sliding doors, swing doors, sliding windows, swing windows, sunrooms, etc.

This article will introduce the top ten system door and window brands in China, including Belima doors and windows, Peiya doors and windows, Huangpai doors and windows, Xinbiao doors and windows, Xuge doors and windows, Xinhaoxuan doors and windows, Feiyu doors and windows, Senying doors and windows, Xuannis doors and windows, and Meishen doors and windows.

This article will recommend the top ten system door and window brands to you, including Belima doors and windows, Mercer doors and windows, Xuge doors and windows, Ouzhe doors and windows, YKK doors and windows, Huangpai doors and windows, Paiya doors and windows, Xinhaoxuan doors and windows, Beckluo doors and windows, and Senying doors and windows.

This article will recommend the top ten brands of doors and windows to you, including Belima doors and windows, Paiya doors and windows, Huangpai doors and windows, Hennessy doors and windows, Ouzhe doors and windows, Mercer doors and windows, Senying doors and windows, Xinhaoxuan doors and windows, Xuge doors and windows, Fuxuan doors and windows.

The top ten brands of system doors and windows are on the list: Xuge doors and windows, YKK doors and windows, WICONA doors and windows, Senying doors and windows, Mercer doors and windows, Ozhe doors and windows, Huangpai doors and windows, Belima doors and windows, Xiluo doors and windows, Becklo doors and windows, etc. Xuge Doors and Windows Xuge Doors and Windows adopts advanced production technology to ensure the precision and consistency of the product.

As a model of high-end aluminum alloy doors and windows, Paya doors and windows always put quality and innovation first. Its products adopt advanced production processes and technologies to ensure that every door and window meets the highest quality standards.At the same time, they constantly innovate, lead the market trend, and satisfy consumers' pursuit of high-quality life.