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为啥奥运会射击只有十米? 第1页

  

user avatar   smartiejl 网友的相关建议: 
      

看了前面几个强答,都是本末倒置的去强调“靶子小”,却没有一个对气枪发展史有基本的知识和概念。

国际射联(包括奥运会)的气枪射击距离是10米,是因为20世纪初设立这个项目时,受当时的气枪技术所限,动力组功率太低,15米以外就很难保证高精度了。而且当年使用的还是弹簧活塞枪,那个枪内主弹簧的震动不可预测不说,还在粒弹被射出前就叠加在枪管上,一不小心就是天女散花的精度。不受弹簧震动干扰的单次泵压式气枪于70年代开始在比赛中普及后,才彻底淘汰了弹簧枪。而预压式气枪(PCP)开始垄断赛场,是90年代才开始的。

而气枪的功率有限,也影响了可以使用的弹粒口径,口径大了弹重就会高,功率不够的话就会限制初速让有效射程缩短,甚至产生“尿弹”式的弹道。传统的.177(4.5毫米)口径,其实就是延续了19世纪末弹簧气枪的“BB”号铅弹的口径,那是当时实用性最为平衡的口径。直到后来更加强劲可靠的动力组设计出现,.22(5.5毫米)口径的粒弹才开始在一些领域替换了.177口径。

而ISSF和奥运气枪赛多年来定了死规矩,只允许使用.177口径,而且只能用平头弹(wadcutter),因为平头弹击中靶纸后戳出的弹孔边缘比较平滑,易于裁判分数。但是只要看过那个平头粒弹的形状,就知道气动性有多差。气动性能差也限制了最大膛速,基本上超过600fps,平头弹就会因为紊流失稳,弹粒会开始翻滚偏离预定弹道,砸出的也不是圆孔而是钥匙孔。

其实现在的气枪技术其实早就克服了这些局限,枪弹的种类和外弹道性能也日新月异,在50米、甚至100米以外用气枪打小目标一点问题都没有。但奥运会架不住ISSF的规则传统,只允许用低功率(<7.5焦耳)的气枪打.177平头弹,枪长也受限,还只能用机械瞄具。有这些技术参数上的硬限制,不要说打超过10米的距离,只要稍微让射击场所内刮阵风,对外弹道的影响就足以能让所有参赛选手抓狂。所以奥运会气枪比赛定为10米,允许使用支撑性服装和眼遮,而且都是室内赛。

而那些国际射联规则外的气枪比赛,基本上没有一个是使用低功率气枪的,30焦耳以上的功率输出是最低标准,高的可以达到100焦耳,初速媲美.22LR。而使用的枪弹口径也越来越大,甚至连.22口径都不吃香了,基本上.25(6.35毫米)口径的圆头弹(domed pellet)是最低标配,低于这个别想拿名次。更不要说近年来飞速发展的块弹(slug pellet),其实就是一种米涅弹,从.22口径起步,最高出现过20毫米口径,用氦气驱动可以用来干死野猪。

其实国外射击群体早就不满足奥运会的那套单调的玩法了,现在国外气枪运动发展最迅速的是各种打铁靶的速射比赛,比如field target和benchrest airgun,而且基本上是光瞄一统天下。除了这些正式赛事,就是各种狩猎和休闲射击,能翻墙的话还可以搜到某老外吃饱了撑的跑到盐湖上用气枪打200码外高尔夫球玩的视频。

至于说10米气枪赛事的靶子小,那是因为射击距离已经那么近,不小就更没挑战性了。是因为距离短才需要小靶子,不是因为靶子小才距离近。


user avatar   jie-mo-27-49 网友的相关建议: 
      

对,就是因为靶纸太小。为了让你直观感受一下,十米气步枪的靶纸有多大,我用A4纸张给你画了一下,一张普通A4大小的纸能做多少张靶纸,这支钢笔是百乐74,大约14厘米长。

你说的两三百米的那种是胸靶,给你看一下大小,这是我军的制式胸靶。

而且,十米气步枪,弹丸动力是压缩气体,二三百米,子弹在哪儿都不知道了。打二三百米的步枪,得是有枪管膛线火药动力的弹丸。

————————————————————————————————————————————

搞不明白这问题有什么好杠的,人家很简单地在问为什么奥运比赛(气步枪)(射距)只有(十米),结果导向,简单回答就完了,就因为靶纸小逻辑上有什么问题么?扯那么多没用的,把如此简单问题延展这么复杂。

杠就你们赢,靠着贬低别人来抬升自己那就就你们最聪明好了。我们都是砖。

————————————————————————————————————————————

致歉声明:

我错了,昂,此答案脏了各位的眼,抱歉抱歉,非常抱歉。

知乎变成这个样子我深深自责,都是我们的错,与各位无关,让各位丧失了求真知学真理的机会,我只是想说,知识有真伪,真理非公理,可讨论,我抱着非常开放的态度愿与之讨论,真知之路云雨未知,对相同事物的理解千差万别,是与否诸君自行判断,也可思考,综合其他各位答主的答案,对此问题有一基本全局认知,我这条答案抛砖引玉的目的也就达到了。

这个世界之所以如此丰富多彩,是因为社会学科里边,同样的问题,向来没有唯一答案。

对于极个别“知乎怎么变成百度”之类的论调,身为知乎相对早期用户,我从来未将知乎与百度分出高下,也未曾将知乎用户的身份作为一个优越感的体现。

另外,在此,对于持此看法者,我强烈安利其去看知网,与知乎虽一字之差,但知识海洋却云泥之别,那上面都是各大学术大拿呕心沥血,经过无数头秃的夜晚,用自己毕生所学的智慧凝结成的人类文明结晶。是学术百家争鸣之地,单一输出模式,无知乎之类泛知识类网络社交平台之社交逻辑。

最后,糅杂一两句鸡汤文,复用伏尔泰一句话:看与不看,都是你合法的权利,你可以随意行使,杠与不杠,也都是你合法的权利,它都在那里,不悲不喜、不增不减。我不同意你说的话,但我誓死捍卫你杠我的权利。

最后的最后,再次诚恳道歉,我错了,我手欠。


user avatar   wendaofuren 网友的相关建议: 
      

公关公司已经出动了,今夜是无眠之夜。

简单聊聊这种事情一般是怎么被公关没的。

最简单的方式,自然是直接找社交平台,要求彻底热搜,去掉话题词,但是因为阿里之前已经被约谈过两次,这种事情明面上应该不能做了。

但是, 明面上不行不代表没办法。

最常见的,一般是控制“热搜话题词”,比如“某某凡涉嫌性侵”事件,热搜上就只挂个“某某凡”的名字;而这次,明明是“阿里员工受侵害”,却非要把热搜词改成“阿里88”。

减少热搜话题词的信息量,就能减少点进去的人数量。

接着呢,就找大V发布相关微博,发布的微博就带着简化过的“热搜词”,但是微博内容与现在实际发生的事情完全无关。

比如现在阿里的事情应该是“侵害事件有没有发生”。但是就在刚刚这个时间点,却集中有一堆大V发布阿里的其他事情,这怎么看都不够合理。

凭借着高权重,这些大V会占据热搜下的前排,这么做,目的就是浑水摸鱼、模糊视线。


加上互联网讯息更新的快速,时间过去,大家很快就会把事情遗忘到脑后了。

太阳底下没有新鲜事。


希望这次事件不会被模糊掉,希望有罪的人得到惩罚。

等一个真相,而不是公关。


user avatar   wang-xiao-chuan-0926 网友的相关建议: 
      

全面地,从宏观介绍差异的一篇文章:

12 Differences Between Chinese Education and American Education

Posted on June 1, 2007

This analysis is being prepared for a presentation I am going to make at the International Conference on Intercultural Education in Harbin, China on June 22-24. I would be interested in receiving your observations, comments, questions about the differences between Chinese and American educational practices.

  1. Class Size is the first noticeable difference at the middle school and high school level. Teachers typically teach two classes (in an 8 period day) with from 55 to 65 students. American secondary teachers typically teach five or six classes with class sizes ranging from 25 to 30. The Chinese teachers use their non-teaching time to grade papers and to prepare for their classes, except for the head teachers (banzhuren) which will be explained later.
  2. While Americans think the "cohort" concept is innovative, China has been using it for decades. Throughout China, students beginning in a school are put into classes and they stay in those classes with one another for the entire time they are in that school unless higher test scores permit them to move to a more advanced grouping. Understood in the Chinese system is that this group of students will learn each of their subjects together. In America, students are not grouped into such classes. Instead, the 30 students who are together for English class will be randomly split up into any of the other subjects for the next period and the period after that, and so on. The next year, the students are totally mixed up again into different classes. Occasionally, the same class of students will take two courses together, such as English and history, but that is rare. The Chinese carry the cohort concept into the university level as well. My four classes of students stay together for all of their required courses the whole time they are at university.
  3. Chinese students stay in the same classroom for their main classes and their teachers come to them while American students change rooms every period and the room belongs to the teacher. Thus, Chinese students don’t have hallway lockers. Students sit in the same seats for each subject and keep their materials in a shelf under their desk top. Many students have cloth covers for their desk and other means of making it "homey".
  4. Chinese education is built on what Americans call "looping". The teachers of the students in the entering class will also follow their same students to the next grade level and the next. In America, it is very unusual for teachers to move with their students from one grade level to the next at the middle school or high school level let alone to loop for the entire period of time the student is in that school. At the primary school level, students begin in grade one with a teacher and stay with that teacher every year they are in primary school. My university students reflect on that teacher as being so very important to them that they really didn’t want to leave them when it was time to go to middle school. American teachers, on the other hand, tend to specialize in the curriculum and content for a particular grade level and then stay at that level. Sometimes, teachers who want to teach older students will ask to move to a higher grade, but then that teacher would typically stay at that level until retirement. That practice means that in America, subject matter and teacher preference might be valued more highly than student needs or student learning.
  5. Another significant structural difference between American and Chinese schools is the concept of head teacher or "banzhuren". The banzhuren takes additional responsibility in delivering instruction, supervising their specific class of students, and in knowing their students and the families of the students and in communicating with those families. For less than 200 yuan per month more, the banzhuren will arrive at school prior to 7:00 a.m. to prepare for the day and to work with early arriving students. The student day at the middle school ends at 4:55 and the teachers leave shortly after that. The banzhuren will not only teach her specific class that she is in charge of but will also sit in on many other subjects throughout the day so she can monitor the progress of her students with other teachers, counsel her students, and contact the parents of those students if necessary. The banzhuren will monitor her class during lunch and nap with them after lunch. One banzhuren told me that she is like a mother to those students who don’t have the parental support they need. In addition, at Liaoning Normal University Junior Middle School (LNUJMS) thebanzhurens are expected to visit the homes and families of half their students sometime during the first term and the other half during the second term. These visitations would take place on Saturdays or Sundays or on holidays. The banzhurenwill, after three years, receive a bonus based on the academic improvement of her class. In America, the individual teacher is expected to make parent contact when a student misbehaves or is not performing at a satisfactory level. In American secondary schools there is also a person called a guidance counsellor who will assist with parent contact. However, the guidance counsellor will have a case load of 350 to 500 students and she often must resort to group counselling sessions.
  6. The Chinese believe in merit pay and in using student test scores for teacher evaluation. For example, when the 9th graders leave middle school they are tested to see which high school they are qualified to attend. Since the same teachers have had those students for three years, they compare their entry score to their exit score. The classes that showed the most academic gain resulted in that banzhurenreceiving a bonus that might range from 3000 yuan to 6000 yuan (one month or two months pay). The same is true at the high school level. On the other hand, a teacher whose students did not show growth will be evaluated accordingly. At LNUJMS, the math team won first place in the District math contest. As a reward, the four math teachers split a 2000 yuan bonus. The teachers I have talked with like the bonus system. So for years the Chinese have been doing what the American conservatives have been advocating and our teacher unions have been fighting.
  7. Discipline in Chinese schools easier than in American schools. For example, at LNUJMS, I was surprised to find minimal student supervision during lunch and between classes. One administrator and one teacher were in the hallway and no teachers were in their classrooms. The other teachers had gone to their offices to meet with students for academic or disciplinary reasons or for a rest between classes. In America, the time between classes is as short as possible, three, four, or perhaps five, minutes. Students are expected to move from their classroom, go to their lockers to get materials for their next class, and then move to that class. The American teachers are expected to be in the hallways during passing periods because that is when fighting and other misbehaviors occur. It is nearly impossible to even imagine a 10 minute passing period in an American school.
  8. Chinese students are very respectful. When Chinese students recite, they stand; when students hand in a paper, they use both hands as if they were making a presentation of the paper to the teacher; when students refer to their teacher in writing, they often use terminology such as , “Our dear teacher.” In interviewing thebanzhurens, they commented that is their duty to teach students how to do well in life and how to be a man. University students, when asked to recall their middle school and high school years often speak of their teachers in very exalted ways telling how much their teachers meant to them.
  9. Chinese students play active and important roles (zhirisheng) in sweeping the classrooms, scrubbing the steps, serving meals, being class monitors, and helping teachers. Student monitors can be seen wearing special armbands in the hallway, watching to make certain students are doing their twice-daily eye exercises properly, providing leadership on the marching field, watering plants, empty bins, cleaning windows, helping to distribute the daily lunch, and so on. Students always seemed to be carrying out their tasks very seriously and in good humor. The student monitor system is utilized at the university level as well with these appointed students helping the teacher in making copies, distributing and collecting papers, contacting classmates and so on. Like the concept of banzhuren, the concept of zhirishengcannot find its English equivalent due to the different Sino-American educational systems. Most Chinese schools are operated on the zhirisheng system for the purpose of maintaining clean classrooms and schools.
  10. Chinese students buy their textbooks each year and the textbooks are soft cover and relatively thin. The textbooks I looked at had a 2006 copyright and I understand that they all have recently undergone revision. The cost is about $1 for a textbook and $2 for a workbook that accompanies the textbook. Students make heavy use of highlighters and annotations in their books. In addition, the textbooks often have moral lessons built into them. For instance, when a particular scientist is highlighted, aspects of his/her life that are exemplary are extolled, such as hard work, protecting the environment, overcoming obstacles, etc. On the other hand, American textbooks are hard cover, updated every six years (at least in Indiana), and are rented to students. Students are not allowed to mark in their textbooks in America.
  11. It almost goes without saying that the curriculum in China is standard nation-wide and that students have few elective choices. National goals, national curriculum, national expectations, national exercises, and even a national class schedule are all built around the Chinese Education Schema that is based on centuries of tradition. In America, education is primarily the responsibility of the state governments. Counting Washington D.C., there are 51 separate governments that give direction to public schools. Further, except for Hawaii, states are divided into school districts that also have certain autonomies. Indiana, for example, has 292 school districts, 292 different teacher contracts, salary schedules, and sets of working conditions.
  12. Deeply embedded in the Chinese culture is the examination system. Since the Song Dynasty (960 AD), the Chinese have relied on the examination process to identify their governmental leaders. Now the examination system is used to determine which university students are able to attend. These national exams were given on June 7 and 8. Local middle schools were used as test sites and those middle school students had a two day holliday. The test is of such great significance that parents rent hotel rooms nearby so their student can have a quiet lunch and take a nap. I saw one hotel with a big banner wishing students luck on the exam. Students will take either the liberal arts test or the science test. For liberal arts students, the first test, Chinese, was from 9:00-11:30. Students were dismissed and came back for the math test from 3:00-5:00. On Friday, the schedule was the same, with the morning session being geography, politics, and history and the afternoon session being English. The parents filled the street in front of the school and anxiously awaited students coming from the test sites and wanted to know how their child did. Taxi cabs even offer free service to these students to help them get home or to the testing site. My friend Kevin’s uncle took time off work to drive Kevin to the test site, pick him up at noon to take him home, then bring him back. It is huge deal!
    (原文:slkchina.wordpress.com/



  

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