imidazo[1,2-a]pyrazine

What is the main use of the crossbow arrow [1,2-a] for birds?
The system of the crossbow arrow has been around for a long time. The ancient virtuous ability, the crossbow arrow is made to control the enemy and hunt birds, and its function is great. The crossbow arrow [1,2-a] is used to cover the needs of the birds to feed and feed.
According to the "Tiangong Kaiwu" of the watcher, the structure of the crossbow is very delicate. The mechanism of the crossbow can be made in an instant, which is more powerful and easy to master than the bow. The length, weight and material of the arrow are all related to its long-range and medium-range effect.
Use the crossbow to target the birds, and between the mountains, forests, and abyss, the animals rush, and then the crossbow arrows can hit their key points. This is because the crossbow arrows use the power of machinery, and the arrows are stable and strong. And the aiming of the crossbow is easier, so it can accurately target the birds.
In ancient times, the people used hunting as a business, and poultry meat could be used for food, and bird feathers and bird skins could be used for clothing and quilts, or for trade. The crossbow arrow [1, 2-a] is an important means to obtain resources for life. In the army, crossbow arrows are also prepared, which can kill the enemy in wartime. In their spare time, they are used for shooting exercises. The act of targeting birds also means practicing martial arts and training.
In short, the crossbow [1,2-a] bird, not only to meet the needs of living materials, but also to practice martial arts and train troops, played an indispensable role in the production, life and military activities of the ancients.

"Tiangong Kaiwu" has a saying: "The silk, hemp, fur and brown in the world are all of quality, so that the special face can still be used. It is said that the creation of things is not laborious, but I do not believe it." The manufacture of crossbow arrows also requires intensive study and ingenuity in order to become a good weapon. Today's discussion on the synthesis method of crossbow [1,2-a] to crooked is actually the key skill in the manufacture of crossbows.
First, the selection of materials is of paramount importance. "Tiangong Kaiwu" says: "Where a bow is made, bamboo and horn are used as the medium dry, and mulberry is the two." The material of the crossbow should be the same. Bamboo and wood need to be selected with a straight texture and a tough texture to keep the crossbow body solid. The horn takes its toughness and is glued to the crossbow arm to increase elasticity. If the material is curved, it will be difficult for the crossbow arrow to shoot straight. This is the primary cause of the crooked crossbow. Therefore, when selecting materials, it is necessary to carefully identify and eliminate its flaws.
Second, the production process should not be underestimated. As far as the production of crossbow arms is concerned, "cutting wood is dry, cutting bamboo is arrow", and the processing process needs to be accurate. When sawing and cutting bamboo and wood, if there is a slight deviation and it does not go in a straight line, after the crossbow is formed, the crossbow arrow will be easily biased. And when installing the crossbow machine parts, the position is slightly inaccurate, which will also cause the crossbow to be crooked. For example, if the crossbow machine is not installed correctly, the shooter's aiming will be deviated, and the arrow will be crooked. Therefore, the craftsman must be skilled, with rules, moments, quasi, ropes and other tools to measure carefully to ensure that the parts are tightly fitted and the position is accurate.
Third, later debugging is also critical. After the crossbow is made, it needs to be tested and debugged many times. "The hair of the arrow is also the crossbow force; the middle is also the ingenuity." Through the test firing, observe the flight trajectory of the crossbow arrow. If it is biased to one side, it is necessary to adjust the crossbow arm slightly. Or cut off a little wood on one side of the crossbow arm, or adjust the tension of the crossbow string, so that the crossbow arrow flies in a straight line. This process requires patience and meticulous, repeated tests, in order to achieve the best performance of the crossbow, and the arrow will not be shot.
In short, in order to make the crossbow [1, 2-a] upright and not crooked, the selection of materials, the production process and the post-debugging need to be taken into account, and none of them are indispensable. These three complement each other, and only by casting a good crossbow can it be used effectively when shooting and fighting.

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In the realm of war, the crossbow is a sharp weapon to kill the enemy. In ancient times, on the battlefield, when they were in formation, the crossbow soldiers were shooting, and their momentum was like thunder. With the power of opportunity, the crossbow arrows are rapid and accurate, and their range is farther and more powerful than ordinary bows and arrows. During the siege of the city, they can be condescending and shoot at the enemy on the city, making it difficult for them to gain a foothold. In the field, when the enemy is not close, they can be suppressed with dense crossbow arrows, frustrating their sharpness and messing up their positions.
In the hunting realm, the crossbow is also indispensable. In the mountains and forests, beasts are cunning. The crossbow arrow can shoot prey at a long distance because of its accuracy, which not only ensures the safety of the hunter, but also increases the chance of capture. The hunter crouches in a hidden place, waiting for the prey to appear, pulls the crossbow machine, and the arrow is hit, and the prey can rarely escape.
In a place of self-defense and self-defense, the crossbow arrow is also a powerful support. On the way, in case of bandits, the crossbow arrow can instantly defeat the enemy. Its operation is relatively simple, even if a person who is not skilled in martial arts, with a little practice, it can also be used to defend against the enemy and ensure their own integrity.
Furthermore, in the field of exercise and teaching, the crossbow arrow can be used to train soldiers and cultivate archery skills. By learning the crossbow, soldiers can be proficient in the use of weapons, improve military skills, and improve the
From this point of view, the ballista [1, 2-a] has extraordinary effects in many fields such as warfare, hunting, self-defense, and drills, and is a rare weapon.

The cymbal is an ancient musical instrument. It is shaped like a disc, with a central bulge like a hat, and the two pieces hit each other to make a sound. Its physical and chemical properties are unique. According to the records of "Tiangong Kaiwu", the material of the cymbal is mostly copper alloy. This is because the copper has good ductility and casting properties, which can cast the beautiful shape of the cymbal.
From the perspective of physical properties, the cymbal is hard in texture, vibrates and sounds when tapped, and the sound is crisp, loud and far-reaching. Its acoustic characteristics are also important, and the material and shape affect the frequency and timbre of the sound. The size, thickness, and height of the central bulge of the cymbal all have different effects on the sound quality. The sound of the big cymbal is deep and thick, while the small cymbal is crisp and bright.
From a chemical point of view, copper alloys will slowly oxidize in the air to form patina, which is one of the manifestations of their chemical stability. In order to maintain the sound and appearance of cymbals, they need to be properly stored to prevent excessive oxidation.
In terms of the production process, "Tiangong Kaiwu" mentions that high-quality copper materials need to be selected for casting cymbals, which go through multiple processes such as melting, casting, forming, and grinding. This process requires craftsmen to precisely control the temperature and time to ensure the quality and sound of cymbals. The surface of cymbals is often specially treated to enhance their wear resistance and corrosion resistance, and prolong their service life.
In summary, the physical and chemical properties of cymbals, from the choice of materials to the production process, have an important impact on their sound quality, appearance and durability, which is also the subtlety of the traditional musical instrument production process.

Today, looking at the sugar industry in [1,2-a] Xiangxu market conditions, this situation is quite observable.
At the beginning, between the markets here, the sugar industry is still alive. In the streets and alleys, there are vendors who set up stoves to boil sugar, and its fragrance is overflowing, leading passers-by to stop. Because of the beautiful taste of sugar, it has the characteristics of both old and young people. In the past, it was often the taste of the people's tea, and it was also the choice of festival gifts. Therefore, at that time, although the business scale was mostly small, there were many buyers, and the business could be maintained.
However, the years passed, and the market conditions gradually changed. Recently, all kinds of new products have entered the market, with a variety of patterns and attracting people's attention. Such as candy from outside the territory, the packaging is exquisite, the taste is novel, and it is very popular with children and teenagers. And its marketing methods are ingenious, widely spread in the city, and the publicity is effective. On the other hand, the method of making sugar is conservative, the style is less changed, and the packaging is also simple, making it difficult to compete with new products in the market.
Furthermore, the pace of life is getting faster and faster, and people are busy with their livelihoods, so they have no time to taste the taste of sugar. In the past, the sight of sugar burning around the furnace is becoming increasingly rare. In addition, the price of labor and materials is gradually rising, the cost of sugar is rising, and if the price increases, there will be fewer buyers, and the dilemma of merchants will become more and more difficult to operate.
In addition, the planning and changes of the city, the renovation of old streets, the relocation of markets, and the difficulty of sugar vendors to find a stable place to operate because of the venue. Many factors are mixed, causing sugar to be in the market conditions of [1,2-a] Xiangxu, no longer as prosperous as before, gradually showing fatigue, and the road ahead is uncertain. It is necessary to make changes to survive, and to adapt to changes in time, in order to hope for a new prosperity.