Precision measurement of the Newtonian gravitational constant

The Newtonian gravitational constant G, which is one of the most important fundamental physical constants in nature, plays a significant role in the fields of theoretical physics, geophysics, astrophysics and astronomy. Although G was the first physical constant to be introduced in the history of science, it is considered to be one of the most difficult to measure accurately so far. Over the past two decades, eleven precision measurements of the gravitational constant have been performed, and the latest recommended value for G published by the Committee on Data for Science and Technology (CODATA) is (6.674 08 ± 0.000 31) × 10⁻¹¹ m³ kg⁻¹ s⁻² with a relative uncertainty of 47 parts per million. This uncertainty is the smallest compared with previous CODATA recommended values of G; however, it remains a relatively large uncertainty among other fundamental physical constants. In this paper we briefly review the history of the G measurement, and introduce eleven values of G adopted in CODATA 2014 after 2000 and our latest two values published in 2018 using two independent methods.     

余华小说《第七天》中的生与死

《第七天》是余华继《兄弟》七年之后完成的最新一部长篇小说，描绘了主人公死去后所经历的事情以及勾起的回忆，为读者展现了一个平等、和谐的死亡世界。经过分析，作品中的生死问题包括三个方面：作品中的人物对死亡没有痛苦或恐惧，能够理性地看待死亡；生与死的意义被颠倒，死亡世界接近理想中的现实世界，更加引人向往；生与死由“爱”这条纽带联系起来，让人们在冰冷中感受到温情。这部小说暴露了大量的社会现实，引人深思，也备受争议。     

Wearable skin-like optoelectronic systems with suppression of motion artifacts for cuff-less continuous blood pressure monitor

According to the statistics of the World Health Organization, an estimated 17.9 million people die from cardiovascular diseases each year, representing 31% of all global deaths. Continuous non-invasive arterial pressure (CNAP) is essential for the management of cardiovascular diseases. However, it is difficult to achieve long-term CNAP monitoring with the daily use of current devices due to irritation of the skin as well as the lack of motion artifacts suppression. Here, we report a high-performance skin-like optoelectronic system integrated with ultra-thin flexible circuits to monitor CNAP. We introduce a theoretical model via the virtual work principle for predicting the precise blood pressure and suppressing motion artifacts, and propose optical difference in the frequency domain for stable optical measurements in terms of skin-like devices. We compare the results with the blood pressure acquired by invasive (intra-arterial) blood pressure monitoring for >1500 min in total on 44 subjects in an intensive care unit. The maximum absolute errors of diastolic and systolic blood pressure were ±7/±10 mm Hg, respectively, in immobilized, and ±10/±14 mm Hg, respectively, in walking scenarios. These strategies provide advanced blood pressure monitoring techniques, which would directly address an unmet clinical need or daily use for a highly vulnerable population.     

琦君散文的语言艺术

琦君散文被视为台湾"闺秀文学"的代表,体现了"闺秀派"文学的艺术特点。琦君散文中穿插运用"口语式的絮语""书卷式的诗语""动态化的叙述语",文风朴实,语言疏淡清朗。     

如何培养大学生的体育能力

大学生的体育能力,集中反映了大学体育教学的质量。在高校体育教学中,除了单纯的运动技术教学,还应该加强培养大学生各方面的体育能力。依据体育发展身体、增强体质这一本质特征,文章从构成体育能力的六种基本成份:身体锻炼能力、运动能力、创新能力、组织管理能力、保健能力、运用体育环境和条件能力,加以论述培养体育能力的方法。     

尊重教育规律促进远程教育发展

基于计算机网络的远程教育在中国虽发展迅速,却问题多多,有些甚至已远远背离了发展远程教育的初衷.本文从探究推动远程教育发展的动因出发,讨论、分析了目前存在的种种问题,并探讨了发展远程教育应注意的问题.     

加强高职高专工科类学生文化素质教育的研究

通过对高职高专工科类学生文化素质状况的调查与研究，探讨如何以就业为导向，抓住振兴老工业基地建设的有利机遇，加强高职高专工科类学生的文化素盾教育。     

市场经济与大学经费来源的多元化

大学经费的短缺几乎是一个世界性的问题。在市场经济条件下,大学经费的来源多元化不仅具有合理性,而且具有必要性和可能性。     

基于粗糙集理论的知识发现

粗糙集理论是一种新型的处理模糊和不确定知识的数学工具。目前已在人工智能、知识与数据发现、模式识别与分类等方面得到了广泛应用。介绍Rough Set理论的基本思想及分析了粗糙集方法的特点,描述一种基于粗糙集理论的知识发现步骤,并以实例作出说明。     

论生育权

本否证了生育权视为一种夫妻之间的身份权的观点，并指出其本质归属应为人格权之构成部分。认为生育权的权能构成应该包括生育请求权、生育决权、生育方式选择权，以此为基础提出了完整的生育权体系的观点。最后，章对生育权的侵权损害赔偿责任认定以及法律上的必要限制也作了阐释。