"Paper" PPT courseware download

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"Paper" PPT courseware download

Part One: The Origin of Paper

Regarding paper, everyone should know what paper is. But, do you know the origin of paper?

1. The origin of paper

Paper is one of the four great inventions of ancient China. It has made outstanding contributions to the spread of culture in history. Even today, when machine-made paper is prevalent, some traditional handmade papers still play an irreplaceable role and shine with their unique brilliance. The appearance of ancient paper can still be seen in the ancient calligraphy and paintings that have been handed down.

Long before the invention of paper, what did people use as note-taking materials? According to literature and physical data, the earliest people used knotted ropes to remember events, and tied a knot when something happened. Later, inscriptions were inscribed on turtle shells and animal bones, which are the so-called "oracle bone inscriptions".

Then, the words are written on the bamboo slips, which are called "bamboo slips". For example, the thicker bamboo slips are called "slips". At the same time, some are also written on silk products.

From the chronological order of the ancient papers unearthed so far, they can be arranged as follows: Fangmatan paper in the early Western Han Dynasty, Baqiao paper, Xuanquan paper, Maquanwan paper and Juyan paper in the middle Western Han Dynasty.

Dry beach slope paper in the late Western Han Dynasty Dry beach slope paper in the late Western Han Dynasty. Not only did these papers predate Cai Lun, but some of them also had ink marks on them, indicating that they had been used for writing documents.

2. How was ancient paper made?

Papermaking: About 3,500 years ago during the Shang Dynasty, my country had characters carved on tortoise shells and animal bones, called oracle bone inscriptions.

In the Spring and Autumn Period, bamboo and wood chips were used to replace tortoise shells and animal bones, which were called bamboo slips and wooden slips. Oracle bones and slips are both heavy and heavy. During the Warring States Period, when the thinker Hui Shi went out to give lectures, he took five carts of slips with him, so there is an allusion to the saying that he learned to be rich in five carts.

In the Western Han Dynasty, the court nobles also used silk or tissue paper to write. Silk is a general term for fine silk and silk. When writing on silk, silk is easy to write on. Not only can you write more than bamboo slips, but you can also draw on it. However, it is expensive and can only be used by a few royal nobles.

Paper already existed in the early Western Han Dynasty in the 2nd century BC. In the first year of Yuanxing (AD 105) of Emperor He of the Eastern Han Dynasty, Cai Lun, based on summarizing the experience of his predecessors in making silk crystals, invented the method of using bark, broken fishing nets, rags, hemp heads, etc. as raw materials to make a silk crystal suitable for writing. Plant fiber paper makes paper a commonly used writing material. It is called "Cai Hou Paper". Cai Lun only improved papermaking, not the inventor of paper.

Paper PPT, part 2: paper production

How is modern paper made?

a. Screening of paper stock: Dilute the prepared paper stock to a lower concentration, and use screening equipment to screen out debris and undissociated fiber bundles again to maintain quality and protect equipment.

b. The mesh part allows the paper material to flow out of the head box on the circulating copper wire mesh or plastic mesh and evenly distribute and interweave it.

c. The pressing part leads the wet paper removed from the screen to a room between two rollers with a felt cloth. By means of the squeezing of the rollers and the water-absorbing effect of the felt cloth, the wet paper is further dehydrated and the paper is made thicker. Tight to improve paper surface and increase strength.

d. Calendering: Since the moisture content of the pressed wet paper is still as high as 52-70%, it is no longer possible to use mechanical force to remove the moisture, so the wet paper is passed through many cylinders with heated steam inside. Surface allows the paper to dry.

e. The moisture content of rolled paper after being pressed is still as high as 52-70%. At this time, mechanical force can no longer be used to remove the moisture, so the wet paper is passed through many cylinders with heated steam inside. Surface allows the paper to dry.

g. Cutting, sorting and packaging: Take multiple paper rolls that have been rolled into tubes, cut them into pieces of paper with a paper cutter, and then sort them manually or mechanically to remove damaged or stained papers. Finally, every five hundred cards are wrapped into a package (usually called a ream).

Paper PPT, Part 3: Saving Paper

How to save paper

When using paper in daily life, try to maximize the use of every piece of paper. For example, both the front and back sides of the paper can be used (for informal occasions), etc. Only when we are environmentally aware can we truly learn to save in our daily work and life. paper

In society, some people have many books that they don’t need but others do: in school, there are many books that are used by the upper grades but can be used by the lower grades. We have to sell them to the waste paper collector for a dime a pound. , let useful books be used to make pulp or wrap candy.

Keywords: Free download of Qingdao version of fourth grade science PPT courseware, first volume, paper PPT download, .PPT format;

For more information about the "Paper" PPT courseware, please click on the "Paper ppt" tab.

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Update Time: 2024-11-22

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