钾原子中多种受激辐射参与的混频过程

当双原子共振激发钾原子于６Ｓ能级时,由光泵受激辐射和电离复合受激辐射参与的六波或四波混频,产生了位于紫外和紫区的诸多相干辐射、文中对多种混频机制进行了分析和讨论,并对所测得的相干辐射线进行了标识．     

对“微波共振跃迁法测量电子偶素2~3S_1-2~3P_1精细结构”实验拟合公式的探讨

本文对Michigan大学S.Hatamian等人在“微波共振跃迁法测量电子偶素2~3S_1-2~3P_J精细结构”实验中所用拟合公式进行了审慎的分析和推证,修正了该公式的功率增宽项,并就Mainz大学R.Ley等人对该公式的批评作了评价。最后,采用新、旧拟合公式对Michigan组实验数据进行拟合并讨论其结果。     

γ—Mo2N合成过程中的热变化及中间产物的研究

采用ＤＴＡ技术，通过改变升温速率研究了γ－Ｍｏ２Ｎ合成过程中的热变化，并经ＸＲＤ，ＢＥＴ及ＩＲ测试，对ＤＴＡ曲线中的谱峰进行归属，考察了中间产物，ＤＴＡ结果表明，在ＭｏＯ３和ＮＨ３程序升温反应过程中有放热峰及吸热峰出现，且随升温速率的长高，放热峰面积与吸热峰面积之比逐渐减小，结合ＸＲＤ及ＩＲ结果可知，ＤＴＡ曲线听放热峰可归属为由ＭｏＯ３变化为ＭｏＯ２的还原峰，吸热峰则归属为由ＭｏＯ２变化为Ｍｏ２Ｎ     

Tandem mass spectrum of a farnesyl transferase inhibitor--gas-phase rearrangements involving imidazole

Compound 1 (1-(3-chlorophenyl)-4-[1-(4-cyanobenzyl)imidazolylmethyl]-2-piperazinone hydrochloride) is a farnesyl transferase inhibitor intended for treatment of cancer. A detailed analysis of the electrospray ionization mass spectrometry and tandem mass spectrometry data of protonated 1 shows that in the gas phase, upon collision-induced dissociation, this ion undergoes complicated rearrangement and fragmentation. These processes include a novel two-step rearrangement. The first step involves a gas-phase intramolecular S(N)2 reaction that forms an intermediate. The second step consists of three competitive rearrangement/fragmentation pathways of the intermediate, giving rise to protonated 2, protonated methylene-imidazole, and a distonic methylimidazole radical cation. Deuterated 1 was studied under the same experimental conditions, and the results strongly support the proposed two-step rearrangement process. It is noted that the unique structure of 1, especially the imidazole ring of 1, plays a critical role in the rearrangement of protonated 1.     

羟基自由基引发的马来酸酐聚合反应机理AM1研究

用AM1方法计算了马来酸酐、羟基自由基及其加成产物α-羟基丁二酸酐基自由基的电子结构、电荷分布和键级.应用前线轨道理论和成键三原则研究了羟基自由基引发下马来酸酐聚合过程中α-羟基丁二酸酐基自由基活性中间体参与反应的可能性及其自由基聚合反应机理.计算结果表明:马来酸酐基态分子的HOMO和LUMO分别对应于双键CC的成键π-MO和反键π -MO;马来酸酐的羟基自由基加成反应活化能计算值为55 7kJ/mol;马来酸酐在羟基自由基引发下的自由基聚合产物是链式结构,与实验事实相符.     

羟基—氧钼(Ⅴ)[5,10,15,20—四(4—磺酸基苯基)]卟啉配合物在溶液中的二聚平衡

在25±0.02℃、0.025mol·dm~(-3)KCl介质及磷酸盐缓冲条件下,用光度滴定法研究了羟基-氧钼(V)[5,10,15,20-四(4-磺酸基苯基)]卟啉配合物在水溶液中的二聚平衡,用线性最小平方法确定了平衡模型,求得二聚反应平衡常数pK_el=4.34±0.28,单体的摩尔吸收εm(447um)=1.27×10~4εm(475um)=2.01×10~4;二聚体的摩尔吸收ε_d(447nm)=3.17×10~4,ε_d(475nm)=1.40×10~4。     

傅里叶变换近红外光谱法测定大麦中蛋白质、淀粉和赖氨酸含量

采用傅里叶变换近红外光谱法测定大麦中蛋白质、淀粉、赖氨酸的含量，并用光谱影响值法(leverage)对异常值进行判断和处理。蛋白质、淀粉和赖氨酸含量近红外光谱分析模型的测定系数R。分别为0．985、0．973和0．978；检验集的化学值与模型预测值的相关系数r分别为0．9853、0．9644和0．9172，分析模型的预测相对标准偏差RSD分别为4．0％、2．4％和5．4％，该结果可替代经典分析方法，满足农产品快速分析的需要。     

Relationship between the molybdenum phases and the conversion of n-butane over Mo/HZSM-5

The conversion of n-C₄H₁₀ was undertaken on MoO₃/HZSM-5 catalyst at 773–973 K and the phases of molybdenum species were detected by XRD. The XRD results show that bulk MoO₃ on HZSM-5 can be readily reduced by n-C₄H₁₀ to MoO₂ at 773 K and MoO₂ can be gradually carburized to molybdenum carbide above 813 K. The molybdenum carbide formed from the carburization of MoO₂ with n-C₄H₁₀ below 893 K is -MoC_1−x with fcc-structure, while hcp-molybdenum carbide formed above 933 K. During the evolution of MoO₃ to MoO₂ (>773 K) or the carburization of MoO₂ to molybdenum carbide (>813 K), deep oxidation, cracking and coke deposition are serious, in particular at higher reaction temperatures, these lead to the poor selectivity to aromatics. Aromatization of n-C₄H₁₀ can proceed catalytically on both Mo₂C/HZSM-5 and MoO₂/HZSM-5, the distribution of the products for the two catalysts is similar below 813 K, but the activity for Mo₂C/HZSM-5 is much higher than that for MoO₂/HZSM-5.