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永利彩票2023-01-31 16:05

几十吨的“胖子”如何“接吻”?太空“红娘锁”今年迎“多场考试”******

  中新网上海5月10日电 题:几十吨的“胖子”如何“接吻”?太空“红娘锁”今年迎“多场考试”

  作者 郑莹莹 马帅莎

  北京时间5月10日凌晨,“快递小哥”天舟四号货运飞船出发了。几个小时后,它抵达目的地,与在轨运行的中国空间站组合体进行快速交会对接。从“发货”到“签收成功”,“天舟四号”仅花了约6.5个小时。

  “从视频里看,我们感觉对接过程是一瞬间完成的,实际上,这整个过程包含了接触、捕获、拉回、锁紧、密封等一系列动作,从对接准备指令发出,到对接锁紧完成,10多个动作一气呵成。”中国航天科技集团八院载人航天工程载人飞船、货运飞船系统副总指挥顾侧峰介绍说。

  中国是继美、俄之后,世界上第三个独立掌握交会对接技术的国家。只有突破交会对接技术,才能开展空间站的组装建造,提供物资运送对接、人员天地往返等。交会对接,是两个航天器在空间轨道上会合,并在结构上连成一个整体的技术,被称为“太空之吻”,交会对接所使用的对接机构则被称为“红娘锁”。

  从2011年“神舟八号”与“天宫一号”的“太空初吻”开始,中国已成功实现19次精准对接,为中国空间站建造奠定技术基础。

  几十吨的“胖子”如何“接吻”?

  作为对接机构的研制单位,中国航天科技集团八院表示,2022年,对接机构将迎来一场“大考”。在“天舟四号”成功与空间站组合体交会对接后,中国空间站还将迎来神舟十四号,问天、梦天两个实验舱等飞行任务,特别是两个实验舱各自与天和核心舱的对接过程,将是对接机构的重量级“太空接吻考试”。

  面对数十吨级的实验舱,对接机构需要确保对得准、对得稳。而其实早在对接机构设计之初,中国航天科技集团八院805所的对接机构分系统设计师们就充分考虑到了未来空间站建造的需求:对接机构需要适应8吨至180吨之间的各种吨位的对接,以及各种方式的对接,包括偏心对接。

  为了让两个重量级的航天器在“太空接吻”时可以轻盈、优雅,设计师们系统性地提出了可控阻尼的控制思路,可以有效缓冲对接机构捕获后产生的巨大撞击能量。

  “红娘锁”成“太空连廊”

  问天、梦天两个实验舱发射后,经状态调整和转位,将长期“停泊”于中国空间站,成为航天员在空间站工作、生活的主要场所。而此时的对接机构,就是航天员往返于工作、生活区的重要通道。

  为了将三个舱段(问天、梦天两个实验舱以及天和核心舱)长期、紧密地固定在一起,对接机构必须锁得牢、锁得紧。此时,对接机构上的12把对接锁起到了关键作用。

  据透露,在后续实验舱的对接任务中,对接机构上的12把对接锁将与天和核心舱的对接机构共同完成锁紧工作,并让其处于自锁状态,以防止外力作用下的非正常解锁。同时,在锁紧的过程中,对接机构对接框面的密封圈将被压紧,以形成密封的连接通道,为航天员在空间站的工作、生活提供一个安全的环境。(完)

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中新网评:美国众议长选举“连续剧”暴露美式民主痼疾******

  中新网北京1月9日电(蒋鲤)在15轮投票表决后,美国众议院议长选举这场“连续剧”终于落下帷幕,众议院共和党领袖凯文·麦卡锡最终成功当选第55任美国众议院议长。这是美国国会过去164年来耗时最久的一次议长选举记录,将美国“对抗式民主”的弊端暴露无遗。

  资料图:美国众议院共和党领袖麦卡锡。中新社记者 沙晗汀摄

  由于两党对立加剧、党派内斗、利益分配不均等因素,众议长选举陷入一场拉锯战。在此次众议长竞选中,美国民主党议员继续抱团,多轮投票中,一票不投麦卡锡,共和党右翼“强硬派”领头的约20人小团体也拒绝投票麦卡锡。

  麦卡锡的当选之路一波三折,除了本人的“政治投机派”角色在国会不受欢迎外,与共和党内部政治分歧关系密切。

  一方面,共和党党内反对者认为,麦卡锡对民主党态度过于软弱,无力对抗民主党控制的参议院和拜登政府,另一方面,因为共和党的多数优势微弱,党内一些影响力较小的派系的政治力量则被放大,有利于他们巩固自己的选票。

  此外,党内反对者也认为,自己的选票没有换取更多利益,希望以此作为筹码换取麦卡锡更大的让步,比如让他们获得众议院重要委员会中的职务。

  作为仅次于美国总统、副总统的政坛三号人物,众议院议长通常由众议院多数党领袖担任,选举几乎没有悬念。然而,麦卡锡此次为当选,不得不做出多个关键让步,其中可能包括恢复一项罢黜议长动议机制,使得众议长的权力被削弱,难以掌控众议院。

  美国有线电视新闻网CNN称,麦卡锡在这场不合时宜的政治勒索中作出让步,这种绥靖政策只会让极端主义势力更加强大。

  这场引发全世界围观的尴尬选举暴露出美国政治存在严重的对立和分化。在权力博弈思维的裹挟下,党派利益凌驾于国家和人民利益之上,美国两党相互拆台,陷入“为反对而反对”的无脑对垒。而即便是一党内,也会因为利益分配问题产生不同的小派系,相互对抗,选票变成了谋利益的工具。

  从国会山骚乱到打破记历史记录的15轮众议长选举,“对抗式民主”让美国政治陷入瓶颈,长期对抗势必会让政客们丧失客观公正的判断能力,其政治阶层是否有能力治理国家也会引发质疑。

  两党之争和党派内斗进一步放大了美国政治体制弊病,美国所谓的“民主”形象,让全世界大跌眼镜。鼓吹以选民利益为先的美式选举,变成了政客们利益置换的游戏,进一步彰显出美国“民主政治”日渐失能,不断极化的党争已使美国政治制度陷入死循环。

  House speaker election reveals deep-rooted problems in U.S. democracy

  (ECNS) -- The Republican leader Kevin McCarthy was elected as the 55th speaker of the U.S. House of Representatives after 15 ballots. As the most grueling House speaker election in the past 164 years, the election has highlighted the defects of the country’s "confrontational democracy".

  The election once reached a stalemate due to intense partisan strife, inner-party struggle among the Republicans, uneven distribution of interests, and more. Democratic Party members forged a close alliance, refusing to vote for McCarthy, while about 20 Republicans also declined to cast ballots for the GOP leader.

  Except for his unpopular role as a "political speculator" in Congress, McCarthy’s hard-won election can be attributed to turmoil within the Republican Party.

  On the one hand, opponents in the Republican Party believe that the GOP leader's attitude toward the Democrats is too weak to confront the Senate controlled by Democrats and the Biden administration.

  On the other hand, the political power of some less influential factions in the Republican Party has been amplified due to the Party’s weak majority advantage in the House of Representatives, which is conducive to consolidating their ticket warehouses.

  Meanwhile, these opponents believe that their votes failed to win them more benefits, hoping to use this as a bargaining chip for McCarthy's further concessions, such as getting them positions in important House Committees.

  As the third political figure after the President and Vice President of the U.S., the speaker, by tradition, is the head of the majority party in the House of Representatives.

  But McCarthy has made many concessions in order to bring the ultra conservatives along, involving what’s known as the “motion to vacate,” a mechanism by which members can force a vote to depose the speaker. The reported concessions will empower individual members at the expense of McCarthy’s sway as speaker.

  CNN thought the concessions he made during this unseemly political shakedown would only make the extremist faction more powerful.

  This embarrassing election, which has drawn global attention, exposed the serious opposition and polarization in American politics. Both Democrats and Republicans put their interests before that of the country and its people, attacking and opposing each other irrationally.

  Besides, different factions arise within a single party and confront each other because of the distribution of interests. Votes have become a tool to win more benefits.

  From Capitol riots to the House Speaker election with record-breaking ballots, "confrontational democracy" has become a bottleneck of American politics. Long-term confrontation will surely impede politicians to think objectively and fairly while their capacity of governing the country will also raise doubts among the public.

  Both parties’ struggle and infighting among the Republicans have further amplified the defects of the American political system, with its "democratic" image shocking the world.

  The U.S.-style election, which advocates putting voters' interests first, has become a game of interest exchange among politicians. In addition, it further demonstrates the malfunction of American "democratic politics" and the constantly polarized party struggle that has trapped the American political system into an infinite cycle.

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