新研发缪子成像技术助力文物古迹安全环保“体检”******
新华社兰州1月8日电（记者张文静、呼涛）经过长期积累与研究，兰州大学核科学与技术学院、稀有同位素前沿科学中心刘志毅教授团队成功研发出高精度宇宙射线缪子成像技术及相关设备，并首次对西安城墙等规模较大的文物古迹进行了健康“体检”。
始建于隋唐、扩建于明代的西安城墙，是中国现存历史最悠久、规模最宏大、保存最完整的古代城垣建筑，对研究中国古代社会的城市建设、历史文化、军事防御和建筑艺术都有很高价值。该团队介绍，历经数百年，西安城墙出现了部分坍塌、沉陷等现象，一些关键病灶深藏在墙体内部，对探测和勘探手段提出了更大挑战。深入了解城墙内部结构，并有针对性地修复，成为文物保护工作者以及科技工作者研究的重要课题。
据介绍，大型目标物的深部成像是长期以来困扰多个领域的难题。常规的内部探测方法有时会破坏目标物结构，不适宜文物古迹的内部探测，因此迫切需要研发更加安全、环保的创新技术和设备。兰州大学研发的高精度宇宙射线缪子成像技术及相关设备则提供了一种全新的解决思路。
“缪子是自然界的基本粒子之一，具有极强的穿透能力，可以实现大型目标物的无接触、深穿透和无损成像，与常规人工射线装置相比具有不可比拟的优势。基于缪子成像技术，我们研发出成套的高精度设备，可以较为精确地对规模较大的文物古迹进行安全的内部探测，助力文物古迹的考古与保护。”刘志毅告诉记者。
该团队表示，在西安城墙管委会的大力支持下，他们利用缪子成像技术及相关设备将西安城墙的58号马面区域作为首次试点探测目标，不仅探明了马面墙内部分区域明显的密度异常体，而且将其位置、形状、大小较为清晰地呈现了出来，是一次成功的实验研究。
记者了解到，该技术还在冰川科考、滑坡监测等领域有着广泛的应用前景。相关研究成果近期发表于《应用物理学杂志》，并被遴选为当期封面文章。
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.
| 网信彩票地图 |
