四面体型含碳簇合物MC4H12的电子结构计算

用四面体含碳原子簇模型MC₄H₁₂(M=C,B)和量子化学的Gaussian76从头计算方法,对金刚石晶体及其代位硼体系的电子结构进行了无调节参数计算。提出了以激发能概念确定原子簇模型的晶体带隙和以原子内层电子能量校正含杂原子簇杂质能级的观点。所得金刚石晶体带隙值以及硼杂质能级在带隙中的位置与实验值及其他有关计算值都符合得很好。     

芳氧乙酰氧(亚甲)基硅烷的合成

本文合成了一系列芳氧乙酰氧(亚甲)基硅烷类化合物,大部分为文献尚未报道的新化合物。利用红外光谱和核磁共振等测定了这些化合物的结构。用切段法测定了其中四个有机硅取代苯氧乙酸酯对小麦的生长刺激活性,发现它们对小麦的生长有一定的促进作用,其效果优于或接近于类似结构的植物生长调节剂2,4-D。     

原子簇模型晶体带隙的计算

本文以金刚石的原子簇模型化合物MC_4H_(12)为例,使用CNDO、INDO、MNDO(对M=C)和ab initio(对M=C,B,N)方法,对原子簇模型晶体带隙和电子结构进行了计算。将原子簇模型的晶体带隙定义为原子簇体系的激发能,其结果普遍地比基态的前线轨道处理法要好得多。另外,还对C_5H_(12)分子的光电子能谱以及N杂质引起的晶格畸变和顺磁共振实验结果作了合理解释。     

PdCOM+(M=Li,Na,K)体系中M+的助催化性能的成键能研究

本文采用成键能判据探讨了模型化合物ＰｄＣＯＭ＾＋分子轨道成键性质和原子间化学键强度，进而说明Ｍ＾＋的助催化性能，得到与文献［２］和实验［３］相符的结论。     

Ion implantation as a tool for studying the Kondo-systemZnMn

In the case ofZnMn alloys it is shown how low temperature ion implantation can be used for the production of dilute magnetic alloys. The Kondo effect in the resistivity (T) was studied between 1.1K and 20 K. The phonon part of the resistivity was subtracted using (T)-curves from Zn-Films with similar disorder produced by self-ion implantation. A logT-dependence with a slope proportional to the Mn-concentration was found below 200 ppm. The influence of disorder on the specific Kondo slope is discussed.Dedicated to Prof. Dr. W. Buckel on the occasion of his 60th birthday.     

Monoterpenes and Sesquiterpenes of Essential Oils from Psidium Species and Their Biological Properties

Psidium (Myrtaceae) comprises approximately 266 species, distributed in tropical and subtropical regions of the world. Psidium taxa have great ecological, economic, and medicinal relevance due to their essential oils’ chemical diversity and biological potential. This review reports 18 Psidium species growing around the world and the chemical and biological properties of their essential oils. Chemically, 110 oil records are reported with significant variability of volatile constituents, according to their seasonality and collection sites. Monoterpenes and sesquiterpenes with acyclic (C₁₀ and C₁₅), p-menthane, pinane, bisabolane, germacrane, caryophyllane, cadinane, and aromadendrane skeleton-types, were the primary constituents. The essential oils showed various biological activities, including antioxidant, antifungal, antibacterial, phytotoxic, larvicidal, anti-inflammatory, and cytotoxic properties. This review contributes to the Psidium species rational and economic exploration as natural sources to produce new drugs.     

Direct observations of single particle fragmentation in the early stages of combustion under dry and wet conventional and oxy-fuel conditions

This article investigates the single particle fragmentation of three solid fuels in the early stages of combustion under dry and wet conventional and oxy-fuel conditions. The three solid fuels studied were a low rank sub-bituminous Colombian coal, a low-rank/high-ash sub-bituminous Brazilian coal, and a charcoal residue from black acacia. Particles, with size in the range 125–150 µm, were burned in a drop tube furnace with a constant wall temperature of 1475?K, under six different mixtures of O₂/N₂/CO₂/H₂O, which allowed simulating dry and wet conventional and oxy-fuel combustion conditions. A high-speed camera was used to record the fragmentation process during the early stages of combustion and the collected images were treated to characterize the fragmentation mode, probability and time. The observed fragmentation modes are characterized by the occurrence of exfoliation, radial fragmentation or a combination of both. The results disclose that the fragmentation mode is strongly affected by the fuel type, but less affected by the atmosphere; the fragmentation probability is strongly affected by both the fuel type and the atmosphere; and, finally, fragmentation in air occurs significantly dispersed after ignition, but it tends to cluster closer to the ignition under simulated oxy-fuel conditions.     

I群-D2群V系数

本文讨论了I群-D₂群V系数,给出在I群单值表示下的计算值。将以I群为出发点的群分解链延伸到其D₂子群。还列出了D₂群V系数的计算结果。