新郑西亚斯东周玉器材料属性与加工工艺的科技分析

中国玉文化源远流长，治玉工艺经过各个时代的不断发展和完善，在一定程度上能反映古代社会生产力发展水平及文化、贸易、技术交流等信息。利用能量色散型X射线荧光光谱（EDXRF）、激光拉曼光谱（LRS）、超景深光学显微系统（OM）等分析技术，结合硅胶覆膜微痕复制技术，对河南省新郑西亚斯东周墓地出土的一批玉器进行科技分析。首先利用化学成分和物相结构分析技术确定了玉器材质的矿物属性，其次利用显微分析技术表征了玉器表面及穿孔内部和印模的加工痕迹，特别是阴刻纹饰和穿孔微痕特征，最后探讨了玉器样品的材料属性和加工工艺两者之间的联系。化学成分和物相结构分析结果表明，所分析的西亚斯东周玉器材质丰富，主要矿物组成有滑石、透闪石、水晶、云母等。玉器表面纹饰微痕特征分析表明，所分析玉器阴刻工艺采用了两种加工工具，分别是砣具和手持硬质工具。穿孔微痕分析特征表明，钻孔包括单面钻孔和双面/多面钻孔两种方式，钻孔工艺则有实心钻、管钻等。部分玉器钻孔形状和内部微痕特征表明，尽管均采用了实心钻工艺，但所采用的实心钻头在形状上存在差异，同时，也存在是否配合解玉砂进行钻孔的差异。不同材料属性的玉器采用了不同的加工工艺。滑石质玉器，莫氏硬度1，器型主要为玉片饰，其表面阴刻纹饰主要采用手持硬质工具进行刻画，钻孔主要采用了双面钻孔方式，并使用了实心钻头未添加解玉砂进行加工，钻头形状可能为圆锥状；云母质玉器，莫氏硬度2~3，器型主要为玉玦片饰，纹饰采用了砣具添加解玉砂的加工工艺，钻孔方式为单面钻孔，采用了管钻工艺。透闪石型玉器，莫氏硬度5~6，器型主要为玉片饰，表面纹饰采用砣具配合解玉砂砣刻，以双面钻孔的方式为主，钻孔工艺为实心钻头配合解玉砂工艺，钻头形状与滑石类样品一致，为圆锥状。水晶质玉器，莫氏硬度7，均为珠饰，表面无纹饰，钻孔方式为双面/多面钻孔，钻孔工艺为实心钻配合解玉砂工艺，且钻头可能为圆柱形。研究结果表明，玉器表面纹饰所采用的阴刻工艺和钻孔工艺，与玉器本身的材料属性、器型等存在密切关系。     

DISCUSSION ON TWO PROBLEMS OF THEORETICAL MECHANICS IN COLLEGE MECHANICS COMPETITION1)

针对两道力学竞赛试题,从欧拉动力学方程出发分别给出了更加简化的固连系选取方法,分别命名为"Serret-Andoyer近似固连系"和"虚固连系",在此基础上对第1届全国青年力学竞赛理论力学试题第9题,拓展讨论了大球同步旋转时,小球的稳 定性条件,结果表明后者的稳定临界转速要求更低,这将更有利于提高旋转结构的稳定性;对第12届全国周培源大学生力学 竞赛第3题,剖析了任一纬度的运动规律,发现当体系初始角动量为零时会出现一种简洁又优美的运动模式。     

THE DEVELOPMENT OF NATIONAL ZHOU PEIYUAN COMPETITION ON MECHANICS

全国周培源大学生力学竞赛为《力学与实践》编委会发起并承办的一项大学生科技赛事,经过三十多年的发展,已经成功举办了12届,也成为展示高校力学教学水平的一个窗口。在《力学与实践》创刊40周之际,本文对全国周培源大学生力学竞赛的发展历程和组织模式进行了较为系统的回顾和梳理;对各届的组织规模和创新形式进行归纳与汇总;并通过案例说明力学竞赛对力学教学和人才培养所发挥的作用。     

周郇和《电学纲目》

本文根据新发现的资料,对首次将经典电磁学较为系统地介绍进我国的周郇及其译著《电学纲目》作了述评.     

Component Analysis and Anti-Colorectal Cancer Mechanism via AKT/mTOR Signalling Pathway of Sanghuangporus vaninii Extracts

Sanghuangporus vaninii (Ljub.) L.W. Zhou & Y.C. Dai (SV) is a major cultivar of Sanghuang, which is well known as an excellent anti-tumour drug and reaches the mainstream market in China. Water, 60% ethanol and 95% ethanol were used to extract the drug, and three kinds of polar extracts were obtained separately. Compared with water extracts and 95% ethanol extracts, the 60% ethanol extract had the highest flavonoid content, and its polysaccharide content was greater than that in the 95% ethanol extract and lower than that in the water extract. Its essential components were phenolics whose majority were phenolic acids, flavonoids and phenylpropanoids. This extract has better inhibition effects on the proliferation of SW480 human colon cancer cells, inducing cell apoptosis and blocking G2/M period cells. It can significantly inhibit gene expression and reduce the activation of the AKT/mTOR signalling pathway. The anti-cancer activity of the 60% ethanol extract is satisfactory and may be a result of the combined effects of polysaccharides and flavonoids. The data suggest that the 60% ethanol extract can be used as an adjuvant for chemotherapy and as a potential anti-cancer agent with broad development prospects.     

Matrices over Zhou nil-clean rings

A ring R is Zhou nil-clean if every element in R is the sum of two tripotents and a nilpotent that commute. Let R be a Zhou nil-clean ring. If R is 2-primal (of bounded index), we prove that every square matrix over R is the sum of two tripotents and a nilpotent. These provide a large class of rings over which every square matrix has such decompositions by tripotent and nilpotent matrices.     

Date identification of the Zhouji materials during the period of King Xin--The chronology Solving method of oracle boneS and bronzes in the Shang and Zhou dynasties

By identifying the dates of the Zhouji materials (one kind of oracle bone) during the period of King Xin (also called Zhou the last monarch in Shang Dynasty), this paper establishes a new "Direct Solving Method" (DSM) to solve the chronology problems in the Shang and Zhou dynasties. The mathematical models are more suitable for those materials with the Ganzhi (the Heavenly Stems and Earthly Branches, the Chinese ancient date recorded method being of the 60-day cycle, that the repetitive cycle is independent of any astronomical parameter, each day within this cycle has its own name and can also be expressed by the numbers from l to 60) record of the date, lunar month, and their year intervals and all of them are in history documents, oracle bones and bronze vessels. For example, taking the 12 Zhouji materials in the period of King Xin,we derive the two best results of the first year when Xin assumed the reins of government in probably 1063 BC or 1052 BC.     

Asymmetric synthesis of spirocyclohexanone-pyrrolidine via AgI-catalysed asymmetric 1,3-dipolar cycloaddition of azomethine ylides

Cinchonine was effectively used in an AgOAc-catalysed asymmetric 1,3-dipolar cycloaddition of azomethine ylides with 2,6-bis(arylmethylidene) cyclohexanones, affording spiropyrrolidine derivatives with excellent yields (up to 99%), diastereoselectivities (up to 96:04 dr), and enantioselectivities (up to 99% ee).