高压深孔YDS环氧化学灌浆技术在大岗山水电站Ⅴ_1类辉绿岩脉地层帷幕灌浆科研试验中的应用

采用高压深孔YDS环氧化学灌浆技术,对大岗山水电站Ⅴ1类辉绿岩脉地层帷幕进行现场试验,总结出用水泥/化学复合灌浆对该帷幕大规模施工的设计参数及工艺措施。试验结果表明,用水泥灌浆与YDS高渗透性环氧化学灌浆材料灌浆组成的水泥/化学复合灌浆方式在大岗山水电站能够形成可靠的防渗帷幕,该工艺技术是可行的。     

化学灌浆技术的传承与发展——写在中科院广州化灌工程有限公司成立35周年之际

简述了我国化学灌浆技术的发展历程,介绍了中国科学院广州化学研究所在化学灌浆技术领域所取得的成就,重点介绍了中科院广州化灌工程有限公司成立以来对研究所化学灌浆技术的传承及35年来对化学灌浆技术发展所取得的创新成果,展望了未来化学灌浆技术的发展前景。     

SGLT2抑制剂偕二甲基化Canagliflozin的设计、合成与活性研究

由1-(5-溴-2-甲基苯基)-1-甲基乙醇(1)通过6步反应,制得了钠-葡萄糖协同转运蛋白2(SGLT2)抑制剂偕二甲基化canagliflozin,总产率38.1%,其中关键的一步是叔醇和噻吩发生的傅-克烷基化反应。利用1H NMR、13C NMR和HR-MS表征了最终产物的结构。最终产物利用大鼠尿糖排泄试验(UGE)进行了活性评价,结果显示合成的化合物具有一定的尿糖诱导能力,但不如母体化合物canagliflozin活性高。     

金属化学标准样品均匀性复检计算优化方案

根据本所多年制作金属化学标准样品和原子吸收光谱仪器进行各种标准样品均匀性复检的实际工作经验,对全国通用的该均匀性复检的统计数学模式所存在的问题从数理和实际运用上加以探讨。加了重要的模式计算的限定条件,编制了更合理优化的计算机程序。以使得各类化学和仪器的分析的标准样品的均匀性复检统计荼更准确可靠。     

第29届中国化学奥林匹克(决赛)实验试题的设计与解析

详细介绍和评析了第29届中国化学奥林匹克决赛实验试题;并详细介绍了实验设计思路和筛选过程,给出了评分规则制定的原则。     

从化学实验竞赛探讨高校化学实验教学的改革和创新*——第11届全国大学生化学实验邀请赛理论试题的解析与思考

从命题思路、试题内容及特点和结果分析等3个方面对第11届全国大学生化学实验邀请赛的理论试题进行讨论分析和总结,同时对化学实验教学的改革提出几点思考和建议,以期促进高校化学实验教学的改革和创新。     

Molecular Design in Practice: A Review of Selected Projects in a French Research Institute That Illustrates the Link between Chemical Biology and Medicinal Chemistry

Chemical biology and drug discovery are two scientific activities that pursue different goals but complement each other. The former is an interventional science that aims at understanding living systems through the modulation of its molecular components with compounds designed for this purpose. The latter is the art of designing drug candidates, i.e., molecules that act on selected molecular components of human beings and display, as a candidate treatment, the best reachable risk benefit ratio. In chemical biology, the compound is the means to understand biology, whereas in drug discovery, the compound is the goal. The toolbox they share includes biological and chemical analytic technologies, cell and whole-body imaging, and exploring the chemical space through state-of-the-art design and synthesis tools. In this article, we examine several tools shared by drug discovery and chemical biology through selected examples taken from research projects conducted in our institute in the last decade. These examples illustrate the design of chemical probes and tools to identify and validate new targets, to quantify target engagement in vitro and in vivo, to discover hits and to optimize pharmacokinetic properties with the control of compound concentration both spatially and temporally in the various biophases of a biological system.     

The Participation of 3,3,3-Trichloro-1-nitroprop-1-ene in the [3 + 2] Cycloaddition Reaction with Selected Nitrile N-Oxides in the Light of the Experimental and MEDT Quantum Chemical Study

The regioselective zw-type [3 + 2] cycloaddition (32CA) reactions of a series of aryl-substituted nitrile N-oxides (NOs) with trichloronitropropene (TNP) have been both experimentally and theoretically studied within the Molecular Electron Density Theory (MEDT). Zwitterionic NOs behave as moderate nucleophiles while TNP acts as a very strong electrophile in these polar 32CA reactions of forward electron density flux, which present moderate activation Gibbs free energies of 22.8–25.6 kcal·mol⁻¹ and an exergonic character of 28.4 kcal·mol⁻¹ that makes them irreversible and kinetically controlled. The most favorable reaction is that involving the most nucleophilic MeO-substituted NO. Despite Parr functions correctly predicting the experimental regioselectivity with the most favorable O-CCCl₃ interaction, these reactions follow a two-stage one-step mechanism in which formation of the O-C(CCl₃) bond takes place once the C-C(NO₂) bond is already formed. The present MEDT concludes that the reactivity differences in the series of NOs come from their different nucleophilic activation and polar character of the reactions, rather than any mechanistic feature.     

Use of Sucrose‐based Epoxy ­Formulations and Cellulosic Fibers in ­the Design,Preparation, and Screening ­of New Composite Insulation Materials

Non‐woven composite insulation materials were generated from cotton, kenaf, jute, polyester, polypropylene, sucrose‐based epoxy formulations, and aluminum foil. The needlepunched fiber batts were rendered flame resistant by use of inorganic reagents and urea. To discover suitable epoxy formulations to bind the cellulose fibers to themselves or to dissimilar surfaces and to make flexible composites, a comparison of the performance of the known epoxy allyl sucroses (EAS), epoxy crotyl sucroses (ECS), and diglycidyl ether of bisphenol‐A (DGEBA) was made. The epoxies were cured with commercial diethylenetriamine (DETA), and UNIREZs‐2142 and 2355®, to discover a formulation with the following characteristics: (a) low cure temperature; (b) low Young's moduli and glass transition temperatures of cured thermosets for flexible composites; (c) ample bond strength between the fabric and the bonded surfaces; and (d) non‐cytotoxicity and non‐mutagenicity of the epoxies. Based on results following these criteria, EAS was selected, and the formulation comprising EAS and UNIREZ‐2355® was deemed suitable to bind fiber batts to surfaces of any type and geometry. ASTM guidelines were used to construct a wooden frame cube (heat box) for the simultaneous rapid screening of cellulosic fiber batts and composites. The new materials were compared against R‐19 fiberglass insulation for their ability to resist heat flow (denoted by relative R‐values) and time taken to approach thermal equilibrium. Plain non‐woven cellulosic fiber batts showed relative R‐values of 4.0 °F ft² hr/Btu per inch thickness (0.27 K m²/W per cm), and took about 2 hr to establish equilibrium heat flow. Commercial fiberglass batts showed relative R‐values­of 2.2 per in (0.15 per cm) and took 1 hr to attain equilibrium heat flow. When 6.25 in (15.9 cm) thick batts of fiberglass were needle punched to a thickness of 1 in (2.54 cm), relative R‐values and equilibrium heat flow times were 4.0 per in (0.27 per cm) and 2 hr, respectively. This denoted that the densities and thermal resistances of non‐conducting materials are raised concurrently. Anisotropic heat flow behavior was observed in cellulosic fiber composites with aluminum foil (shiny side out) bonded on one side. It depended upon whether the aluminum foil side or the fibers side faced the heat source. In the latter orientation the aluminum acted as a heat sink, and in the former orientation the foil acted as a poor heat reflector. The poor performance of these insulation composites was related to the fact that aluminum was directly bonded to the fiber batts and was acting as a heat conductor. When cellulose fiber shims (spacers) were placed between the fiber batts and the aluminum foil, the R‐values of the composites were comparable to those of plain batts but the times taken to approach thermal equilibrium increased to >3 hr, denoting that the foil was acting more as a reflector and less as a conductor. Copyright © 2001 John Wiley & Sons, Ltd.