丙烯-甲醇-水三元体系汽液相平衡研究(英)

用静态平衡釜法测定丙烯－水－甲醇三元物系在30～60C,0．3～0．9MPa下,甲醇－水比例为9∶1、8∶2、7∶3时的汽液平衡数据,用Peng－Robinson模型方程对汽液平衡数据进行了关联,求得各模型参数,其中液相丙烯的平均相对偏差为1．46％,结果令人满意     

两类聚苯胺复合基体手性材料吸波性能的研究

我们制备了MnZn铁氧体聚苯胺复合基体和Fe3O4聚苯胺复合基体的碳纤维手性材料,利用微波国波导法在8．5－11．0GHz频宽内测量了各手性材料的电磁参量,计算出自由空间中的短路反射系数。对短路反射系数受频率、基体中铁氧体浓度的影响作了分析。     

数字视频后处理芯片及系统应用方案

数字视频后处理专用集成电路及其应用方案是基于数字电视业务的多样性提出的,其市场潜力巨大,目前国内市场却被国外商家垄断。该文介绍了杭州国芯科技视频后处理芯片GX2001的功能框架和性能,并从应用的角度介绍了系统方案。该芯片的出现填补了我国数字电视核心自主知识产权芯片的空白,与国外同类芯片相比．该芯片更符合我国国情,满足整机厂家和市场需要,系统实现方便,具有更高的性价比。     

母子公司财务控制关系浅析

由于企业集团规模迅速扩张,使得管理制度与管理措施滞后,不能适应企业集团的发展需要,造成国有资产严重流失。本就此问题,提出了集团公司如何对子公司的经营管理进行有效地控制,特别是对加强财务控制方面进行了探讨。     

Electrical conductivity of melts: implications for conductivity anomalies in the Earth's mantle

Magmatic liquids, including silicate and carbonate melts, are principal agents of mass and heat transfer in the Earth and terrestrial planets, and they play a crucial role in various geodynamic processes and in Earth''s evolution. Electrical conductivity data of these melts elucidate the cause of electrical anomalies in Earth''s interior and shed light on the melt structure. With the improvement in high-pressure experimental techniques and theoretical simulations, major progress has been made on this front in the past several decades. This review aims to summarize recent advances in experimental and theoretical studies on the electrical conductivity of silicate and carbonate melts of different compositions and volatile contents under high temperature and pressure. The electrical conductivity of silicate melts depends strongly on temperature, pressure, water content and the ratio of non-bridging oxygens to tetrahedral cations (NBO/T). By contrast, the electrical conductivity of carbonate melts exhibits a weak dependence on temperature and pressure due to their fully depolymerized structure. The electrical conductivity of carbonate melts is higher than that of silicate melts by at least two orders of magnitude. Water can increase electrical conductivity significantly and reduce the activation energy of silicate melts. Conversely, this effect is weak for carbonate melts. In addition, the replacement of alkali-earth elements (Ca²⁺ or Mg²⁺) with alkali elements causes a significant decrease in the electrical conductivity of carbonate melts. A distinct compensation trend is revealed for the electrical conductivity of silicate and carbonate melts under anhydrous and hydrous conditions. Several important applications of laboratory-based melt conductivity are introduced in order to understand the origin of high-conductivity anomalies in the Earth''s mantle. Perspectives for future studies are also provided.     

无水K2CO3催化合成α-呋喃丙烯酸

以呋喃甲醛和乙酸酐为原料,采用Perkin反应合成α-呋喃丙烯酸,并对影响产物产率的因素进行了研究．结果表明,α-呋喃丙烯酸最佳的合成条件为：n（呋喃甲醛）：n（无水K2CO3）：n（乙酸酐）=1：0．56：2．33,在150℃下回流反应30min,α-呋喃丙烯酸产率可达71．6％．产物的结构用FT—IR进行了确证．     

无水K2CO3催化合成苯偶姻乙酸酯

以VB1为催化剂,苯甲醛为原料,通过安息香缩合反应得苯偶姻,再以无水K2CO3为催化剂,苯偶姻和乙酸酐通过酸酐醇解反应合成苯偶姻乙酸酯,研究了反应时间、碳酸钾、苯偶姻与乙酸酐的投料比对产品产率的影响．结果表明最佳的反应条件为：n（碳酸钾）：n（苯偶姻）：n（乙酸酐）=1：2：10,在70℃水浴中回流反应60min,获得的苯偶姻乙酸酯产率高达96．1％,并通过IR和^1HNMR对苯偶姻乙酸酯的结构进行了表征．     

完全连续的双参数C0半群

为了丰富半群理论,在对双参数C0半群概念界定的基础上利用经典的算予半群理论,引入了完全连续双参数C0半群的概念,得出了完全连续双参数C0半群的由其无穷小生成元所刻划的特征,并讨论了单参数C0完全连续性与双参数C0半群完全连续性之间的联系．     

海水中微量Co和Ni分析方法的初步研究

综合对比几种水体中微量Co、Ni的萃取和分析方法,选取一种较为可行的方法进行初步尝试,测定海水中的微量Co、Ni;使用原子吸收参照海洋标准GB17378.4-2007中连续测定Co、Pb、Cd的萃取方法对海水中的微量Co、Ni进行萃取和测定。测试结果表明,线性在0.05μg/L~10.0μg/L能够得到较为稳定的测试结果,精密度RSD(Co)=4.9﹪,RSD(Ni)=4.9﹪。该萃取方法能够快速、有效、且稳定的测定海水中的微量Co和Ni。     

The effect of chalk on the finger–hold friction coefficient in rock climbing

The main purpose of this study was to examine the effect of chalk on the friction coefficient between climber's fingers and two different rock types (sandstone and limestone). The secondary purpose was to investigate the effects of humidity and temperature on the friction coefficient and on the influence of chalk. Eleven experienced climbers took part in this study and 42 test sessions were performed. Participants hung from holds which were fixed on a specially designed hang board. The inclination of the hang board was progressively increased until the climber's hand slipped from the holds. The angle of the hang board was simultaneously recorded by using a gyroscopic sensor and the friction coefficient was calculated at the moment of slip. The results showed that there was a significant positive effect of chalk on the coefficient of friction (+18.7% on limestone and +21.6% on sandstone). Moreover sandstone had a higher coefficient of friction than limestone (+15.6% without chalk, +18.4% with chalk). These results confirmed climbers' belief that chalk enhances friction. However, no correlation with humidity/temperature and friction coefficient was noted which suggested that additional parameters should be considered in order to understand the effects of climate on finger friction in rock climbing.