粗糙表面涂覆目标的太赫兹波散射特性研究

对具有涂覆层目标的太赫兹波段粗糙表面的散射特性进行了研究. 考虑到表面粗糙度的影响, 可先对反射系数进行修正, 再利用反射系数对等效电磁流进行修正, 得到粗糙涂覆表面的等效电磁流, 然后在物理光学方程的基础上得到粗糙表面涂覆目标的雷达散射截面; 最后进行图形电磁学可视化计算, 并采用Visual C++对模型进行OpenGL显示, 提取像素面元的有效信息对所得理论进行了仿真分析, 研究了不同入射角度、不同频率、不同介质、不同粗糙度和不同涂层厚度下的太赫兹波电磁散射特性, 得到了一些有参考价值的结论.     

AuQ+碰撞氦原子单电离的全微分截面

利用三体扭曲波计算了3.6 MeV/amu的Au^Q+ (Q=24,53)碰撞氦原子单电离的全微分截面,其结果与实验数据和其它理论进行了比较,表明全微分截面受到高电荷入射粒子的强烈影响,敲出的电子被“拖拽”沿着向前的方向. 但是,所有的理论结果都不能呈现实验上全微分截面的独特的向前峰.     

氟比洛芬酯对子痫前期患者剖宫产术后静脉自控镇痛疗效观察

目的 观察氟比洛芬酯复合丁丙诺啡和单用丁丙诺啡对子痫前期患者剖宫产术后静脉自控镇痛（PCIA）的临床效果和 应用价值。方法 选择90例ASAⅠ～Ⅱ级在腰硬联合麻醉下行子痫前期剖宫产术患者,按随机数字表法分为A组（胎儿娩出后氟比洛芬酯+术后丁丙诺啡PCIA）、B 组（术后氟比洛芬酯+丁丙诺啡PCIA）和C 组（术后丁丙诺啡PCIA）,每组30例。观察并记录患者术后1、2、4、12、24h 视觉模拟评分（VAS）、Ramassay镇静评分,平均动脉压（MAP）、心率（HR）及术后恶心、呕吐、嗜睡、皮肤瘙痒等不良反应发生情况,分别于麻醉前、术后4、12 和24h抽取静脉血,检测血清肾上腺素、去甲肾上腺素、多巴胺、血浆儿茶酚胺和内皮素的水平。结果 A 组和B组患者术后各时点VAS 评分均明显低于C组（P＜0.05）,A 组和B 组各时点Ramsay 镇静评分均明显高于C组（P＜0.05）;A 组和B 组术后各时点MAP 和HR 均明显低于C 组（P＜0.05）;术后24h 内PCIA 按压次数A 组和B 组明显低于C组（P＜0.05）;A 组和B 组术后各时点血清肾上腺素、去甲肾上腺素、多巴胺和内皮素水平均明显低于C 组（均P＜0.05）;A 组术后4h 内皮素水平明显低于B 组（P＜0.05）;A 组和B 组头晕、嗜睡、恶心、呕吐发生率均低于C 组（均P＜0.05）。结论 氟比洛芬酯能有效抑制术后应激,镇痛效果好且不良反应少,在胎儿娩出后应用氟比洛芬酯并结合术后丁丙诺啡进行PCIA更适合用于子痫前期剖宫产术后患者术后镇痛。     

Comparison of the 13C (C = N) chemical shifts of substituted N‐(phenyl‐ethylene)‐anilines and substituted N‐(benzylidene)‐anilines

Comparison of ¹³C NMR of C = N bond chemical shifts δ_C(C = N) in substituted N‐(phenyl‐ethylene)‐anilines XArC(Me) = NArY (XPEAYs) with that in substituted N‐(benzylidene)‐anilines XArCH = NArY (XBAYs) was carried out. The δ_C(C = N) of 61 samples of XPEAYs were measured, and the substituent effect on their δ_C(C = N) were investigated. The results show the factors affecting the δ_C(C = N) of XPEAYs are quite different from that of XBAYs. A penta‐parameter correlation equation was obtained for the 61 compounds, which has correlation coefficient 0.9922 and standard error 0.12 ppm. The result indicates that, in XPEAYs, the inductive effects of substituents X and Y are major factors affecting the δ_C(C = N), while the conjugative effect of them have very little effect on the δ_C(C = N) and can be ignored. The substituent‐specific cross‐interaction effects between X and Y and between Me of C = N bond and substituent Y are important factors affecting the δ_C(C = N). Also, the excited‐state substituent parameter of substitute Y has certain contribution to the δ_C(C = N). Copyright © 2015 John Wiley & Sons, Ltd.     

Zinc‐Catalyzed Borylation of Primary,Secondary and Tertiary Alkyl Halides with Alkoxy Diboron Reagents at Room Temperature

A new catalytic system based on a Zn^II NHC precursor has been developed for the cross‐coupling reaction of alkyl halides with diboron reagents, which represents a novel use of a Group XII catalyst for C? X borylation. This approach gives borylations of unactivated primary, secondary, and tertiary alkyl halides at room temperature to furnish alkyl boronates, with good functional‐group compatibility, under mild conditions. Preliminary mechanistic investigations demonstrated that this borylation reaction seems to involve one‐electron processes.     

Copper‐Catalyzed Cross‐Coupling of Boronic Esters with Aryl Iodides and Application to the Carboboration of Alkynes and Allenes

Copper‐catalyzed Suzuki–Miyaura‐type cross‐coupling and carboboration processes are reported. The cross‐couplings function well with a variety of substituted aryl iodides and aryl boronic esters and allows for orthogonal reactivity compared to palladium‐catalyzed processes. The carboboration method includes both alkynes and allenes and provides access to highly substituted and stereodefined vinyl boronic esters. The alkyne carboboration method is highlighted in the simple one‐pot synthesis of Tamoxifen.     

Organozinc Pivalate Reagents: Segregation,Solubility, Stabilization,and Structural Insights

The pivalates RZnOPiv?Mg(OPiv)X?n LiCl (OPiv=pivalate; R=aryl; X=Cl, Br, I) stand out amongst salt‐supported organometallic reagents, because apart from their effectiveness in Negishi cross‐coupling reactions, they show more resistance to attack by moist air than conventional organometallic compounds. Herein a combination of synthesis, coupling applications, X‐ray crystallographic studies, NMR (including DOSY) studies, and ESI mass spectrometric studies provide details of these pivalate reagents in their own right. A p‐tolyl case system shows that in [D₈]THF solution these reagents exist as separated Me(p‐C₆H₄)ZnCl and Mg(OPiv)₂ species. Air exposure tests and X‐ray crystallographic studies indicate that Mg(OPiv)₂ enhances the air stability of aryl zinc species by sequestering H₂O contaminants. Coupling reactions of Me(p‐C₆H₄)ZnX (where X=different salts) with 4‐bromoanisole highlight the importance of the presence of Mg(OPiv)₂. Insight into the role of LiCl in these multicomponent mixtures is provided by the molecular structure of [(THF)₂Li₂(Cl)₂(OPiv)₂Zn].     

[RhIII(Cp*)]‐Catalyzed ortho‐Selective Direct C(sp2)H Bond Amidation/Amination of Benzoic Acids by N‐Chlorocarbamates and N‐Chloromorpholines. A Versatile Synthesis of Functionalized Anthranilic Acids

A Rh^III‐catalyzed direct ortho‐C?H amidation/amination of benzoic acids with N‐chlorocarbamates/N‐chloromorpholines was achieved, giving anthranilic acids in up to 85 % yields with excellent ortho‐selectivity and functional‐group tolerance. Successful benzoic acid aminations were achieved with carbamates bearing various amide groups including NHCO₂Me, NHCbz, and NHTroc (Cbz=carbobenzyloxy; Troc=trichloroethylchloroformate), as well as secondary amines, such as morpholines, piperizines, and piperidines, furnishing highly functionalized anthranilic acids. A stoichiometric reaction of a cyclometallated rhodium(III) complex of benzo[h]quinoline with a silver salt of N‐chlorocarbamate afforded an amido–rhodium(III) complex, which was isolated and structurally characterized by X‐ray crystallography. This finding confirmed that the C?N bond formation results from the cross‐coupling of N‐chlorocarbamate with the aryl–rhodium(III) complex. Yet, the mechanistic details regarding the C?N bond formation remain unclear; pathways involving 1,2‐aryl migration and rhodium(V)– nitrene are plausible.     

Palladium‐Catalysed Direct Cross‐Coupling of Organolithium Reagents with Aryl and Vinyl Triflates

A palladium‐catalysed cross‐coupling of organolithium reagents with aryl and vinyl triflates is presented. The reaction proceeds at 50 or 70 °C with short reaction times, and the corresponding products are obtained with moderate to high yields, with a variety of alkyl and (hetero)aryl lithium reagents.     

Picolinamides as Effective Ligands for Copper‐Catalysed Aryl Ether Formation: Structure–Activity Relationships,Substrate Scope and Mechanistic Investigations

The use of picolinic acid amide derivatives as an effective family of bidentate ligands for copper‐catalysed aryl ether synthesis is reported. A fluorine‐substituted ligand gave good results in the synthesis of a wide range of aryl ethers. Even bulky phenols, known to be very challenging substrates, were shown to react with aryl iodides with excellent yields using these ligands. At the end of the reaction, the first examples of end‐of‐life Cu species were isolated and identified as Cu^II complexes with several of the anionic ligands tested. A preliminary mechanistic investigation is reported that suggests that the substituents on the ligands might have a crucial role in determining the redox properties of the metal centre and, consequently, its efficacy in the coupling process. An understanding of these effects is important for the development of new efficient and tunable ligands for copper‐based chemistry.