Fluid inclusions evidence for differential exhumation of ultrahigh pressure metamorphic rocks in the Sulu terrane

Since the discovery of coesite and diamond inclusions in eclogites from the Dabie-Sulu orogen, east-central China[1―3], this largest ultrahigh pressure (UHP) metamor- phic terrane in the world has attracted extensive scientific interests. A number of hydrous minerals such as zoisite, phengite, magnesite and talc have been found in the UHP rocks, showing that fluids have played an important role in this type of extreme metamorphic evolution[4―8]. Sev-eral techniques have been applied to th…     

四生散对肺癌细胞增殖的抑制作用及毒性研究

主要探讨中药制剂四生散对人肺癌A5 4 9细胞株的增殖抑制作用以及其急性毒性.应用改进的MTT法测定四生散对肺癌细胞增殖的影响;采用琼脂糖凝胶电泳测定四生散对诱导肿瘤细胞凋亡的影响;再用分剂量组灌胃小鼠的方法,鉴定四生散的急性毒性.实验结果表明,四生散对人肺癌A5 4 9细胞株的增殖有较强的抑制作用,并具有明显的量效和时效相关性;经四生散处理后的A5 4 9细胞呈现凋亡特征性电泳条带;在3 2倍于人的剂量时,小鼠饮食和体重均在正常水平,并无异常,证实口服四生散无急性毒性.     

Optimization of wear parameters of binary Al-25Zn and Al-3Cu alloys using design of experiments

Zinc-aluminum alloys have been used as bearing materials in the past. In recent years, binary Al-Zn alloys and Al-Zn-Cu alloys are being used as an alternative to the Zn-Al alloys for bearing applications. In this study, both binary Al-25Zn and Al-3Cu were prepared using stir casting process. Homogenization of the as-cast alloys was performed at 350℃ for 8 h and then, the alloys were furnace-cooled to 50℃. The homogenization led to the removal of the dendritic structure of the as-cast alloys. After homogenization, wear parameters optimization was carried out using Taguchi technique. For this purpose, L₉ orthogonal array was selected, and the control parameters selected are load, velocity, and sliding distance. The optimum parametric condition was obtained using signal-to-noise (S/N) ratio analysis, and specific wear rate (SWR) is the selected response. The "smaller-the-better" is the goal of the experiment for S/N ratio analysis. After the optimization, confirmation tests were carried out using analysis of variance (ANOVA) from the developed regression equation. Finally, wear mechanism studies were conducted using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) images.     

低能^12C＋^ 12C反应的测量

在鲁尔大学DTL实验室4MV串列加速器上利用^12C束流轰击高纯度的C靶.通过γ谱学方法测量了Ec.m.=2.10-4.75MeV^12C＋^12C熔合蒸发反应,并导出了^12C（^12C,α）20Ne和12C（12C,p）23Na反应的天体物理S（E）＊因子.在Ec.m.≤3.0MeV时发现新的共振.特别是在Gamow峰的高能尾部Ec.m.=2.14MeV处出现强共振峰.当T=8×108K时,这些共振使得α链的反应率比无共振情况下提高了近5倍.     

急进与经常出入高原公路驾驶员生理特性变化试验分析

为了解急进与经常出入高原公路驾驶员生理特性变化规律,寻找提高行车安全的途径,利用生物反馈仪对急进与经常出入高原驾驶员进行实地行车试验。在理论的基础上,定量分析两类驾驶员心电、脑电、肌电指标随驾驶时间、海拔的变化规律,并且建立关系模型。分析结果表明:驾驶员心率增长率与脑电指标R会随着驾驶时间的增长、海拔的升高而逐渐增加;驾驶员肌电指标平均功率频率(MPF)会随着驾驶时间的增长、海拔的升高而逐渐减小;急进高原驾驶员的心率增长率与脑电指标R的增长速度要快于本地驾驶员,而肌电指标平均功率频率(MPF)的下降速度要快于本地驾驶员,表明高原本地驾驶员行车过程中的生理素质要优于急进高原驾驶员。     

Analysis of the formation conditions and characteristics of interphase and random vanadium precipitation in a low-carbon steel during isothermal heat treatment

The characteristics of nanosized precipitates in steels depend on the heat-treatment parameters. The effects of characteristics of vanadium precipitates formed during isothermal heat treatment on the hardness of the ferrite matrix in low-carbon vanadium-alloyed steel were investigated through analysis of transmission electron microscopy images and microhardness measurements. The results show that, during isothermal holding in the temperature range from 675 to 750℃, only interphase precipitation occurs, whereas only random precipitation occurs in the ferrite matrix during holding at 600℃. Furthermore, during isothermal heat treatment between 600 and 675℃, both random and interphase precipitates occurred in the ferrite. Nanoscale vanadium carbides with different atomic ratios of vanadium (V) and carbon (C) were the dominant precipitates in the random and interphase precipitates. The sizes of random precipitation carbides were smaller than those of interphase ones. Also, the sample isothermally heat treated at 650℃ for 900 s exhibited a higher hardness with a narrower hardness distribution.     

Early Cambrian protoconodonts and conodont-like fossils from China: Taxonomic revisions and stratigraphic implications

Tooth likephosphaticprotoconodontsand“con odont likefossils”arecharacteristiccomponentsoftheEarlyCambriansmallshellyfossils (SSF )withaworldwidedistribution .Theyarerepresentedexclu sivelybyisolatedscleritesandareoften presentinaceticacid etchedresiduesfromLowerCambriancar bonates .SincethefirstreportofProtohertzinaMis sarzhevsky 1973fromthebasalCambrianoftheYangtzePlatformin 1977[1] ,andalongwithenthusi asticresearchactivitiesonthesmallshellyfossilsandcandidatesectionsforaglobalPrecamb…     

中央驻豫科研单位专题报道之三 全力打造“撒手锏” 誓做铝业领航者——中国铝业股份有限公司郑州研究院

我们每天都要跟铝打交道,家里的餐具、炊具、门窗、电器,办公室里的电脑、电话、文具、桌椅,工厂里的机器设备,出行乘坐的交通工具,以及潜艇、战机乃至火箭、飞船,铝如影随行、无处不在。铝是一种银白色金属,在地壳中含量仅次于氧和硅,排在第三位。铝的密度小,仅为铁的34.61%、铜的30.33%,因此又被称作轻金属,在世界上产量和用量都仅次于钢铁。它既是常用的生产生活物资,又是重要的战略物资。具有轻便性、导电性、导热性、可塑性(易拉伸、易延展)、耐腐蚀性(不生锈)等优良特性,所以,成为各种设施轻易化的首选金属材料。作为轻型结构材料,铝…     

具有抗艾滋病毒活性的多肽T22([T_(yr)~(5,12),L_(ys)~7]-Polyphemusin Ⅱ)骨架构象模拟

用势能平滑搜索方法,在平滑修饰的势能面上对具有抗艾滋病毒ＨＩＶ－ｌ活性的肽Ｔ２２（［Ｔ５,１２yr,Ｌ７yr］－ＰｏｌｙＰｈｅｍｕｓｉｎ Ⅱ）骨架结构进行了全程搜索,得到该分子骨架结构在修饰势能面上的分子构象全集．用多构象优化方法,选择较适用于肽ＯＰＬＳ力场,采用ＧＢ／ＳＡ水溶剂模型,优化上述构象集,得到Ｔ２２骨架结构在水溶液中优势构象集．结果表明势能平滑搜索与多构象优化相结合的构象分析方法是解决含有环结构的柔性分子构象分析中多重最小问题的有效方法．     

大气悬浮微粒的负面作用

根据新的模拟分析 ,大气中的炭黑对全球气候有很大的增暖作用。无论从气候或人体健康的角度出发 ,均应控制其排放