Ring‐opening copolymerization of ethylene carbonate and ε‐caprolactone catalyzed by neodymium tris(2,6‐di‐tert‐butyl‐4‐methylphenolate): Synthesis,characterization, and dynamic mechanic analysis

The ring‐opening copolymerization of ethylene carbonate (EC) with ε‐caprolactone (CL) was carried out using neodymium tris(2,6‐di‐tert‐butyl‐4‐methylphenolate) as a single‐component catalyst. Copolymers containing up to 22.0% EC contents with high molecular weights (up to 23.97 × 10⁴) and moderate molecular weight distributions (between 1.66 and 2.03) were synthesized at room temperature. Compared with homopoly(ε‐caprolactone), the copolymers with EC units exhibited increased glass transition temperatures (?35.6 °C), reduced melting temperatures (44.5 °C), and greatly enhanced elongation percentage at break (2383%) based on dynamic mechanic analysis. The crystallinities of the copolymers decreased with the increasing EC molar percentage in the products. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4050–4055, 2008     

Improvement of Steroid Biotransformation with Hydroxypropyl-β-Cyclodextrin Induced Complexation

The inclusion complexes induced by cyclodextrins and its derivates have been shown previously to enhance the biotransformation of hydrophobic compounds. Using hydroxypropyl-β-cyclodextrin (HP-β-CD; 20% w/v), the water solubility of cortisone acetate increased from 0.039 to 7.382 g L⁻¹ at 32 °C. The solubilization effect of HP-β-CD was far superior to dimethylformamide (DMF) and ethanol. The dissolution rate also significantly increased in the presence of HP-β-CD. The enzymatic stability of Δ¹-dehydrogenase from Arthrobacter simplex TCCC 11037 was not influenced by the increasing concentrations of HP-β-CD contrary to the organic cosolvents which negatively influenced in the order DMF > ethanol. The activity inhibition effect caused by HP-β-CD was not so conspicuous as ethanol and DMF. Inactivation constants of ethanol, DMF, and HP-β-CD were 5.832, 4.541, and 1.216, respectively. The inactivation energy (E _a) was in the order of HP-β-CD (55.1 kJ mol⁻¹) > ethanol (39.9 kJ mol⁻¹) > DMF (37.1 kJ mol⁻¹).     

金刚石近红外增透滤光保护窗口的制备及应用

报道金刚石近红外增透滤光保护窗口的研制及其在工业中的应用。采用热灯丝化学气相沉积方法成功地制备出金刚石近红外增透滤光保护窗口，其工作波长为１．３￣１．８μｍ，具有良好的光学透过性和优良的物理化学性质。该窗口已在上海宝钢获得成功应用。     

基于分布参数模型的CO_2蒸发器结构参数研究

在设计工况下,建立了用于跨临界二氧化碳热泵热水器的套管式蒸发器的稳态分布参数模型,对其结构参数进行了敏感性分析,指出了它们的合理变化范围:管内套1根管时,内管外径应至少大于11.00mm,低于13.00mm,外管内径应在20.00mm以上,23.00mm以下;管内套多根管时,以管内套3根管的性能为最优。优化设计结果对开发二氧化碳蒸发器产品具有一定的指导意义。     

Synthesis,self‐assembly and drug‐loading capacity of well‐defined drug‐conjugated amphiphilic A2B2 type miktoarm star copolymers based on poly(ε‐caprolactone) and poly(ethylene glycol)

Well‐defined drug‐conjugated amphiphilic A₂B₂ miktoarm star copolymers [(PCL)₂‐(PEG)₂‐D] were prepared by the combination of controlled ring‐opening polymerization (CROP) and “click” reaction strategy. First, bromide functionalized poly(ε‐caprolactone) (PCL‐Br) with double hydroxyl end groups was synthesized by the CROP of ε‐caprolactone using 2,2‐bis(bromomethyl)propane‐1,3‐diol as a difunctional initiator in the presence of Sn(Oct)₂ at 110 °C. Next, the bromide groups of PCL‐Br were quantitatively converted to azide form by NaN₃ to give PCL‐N₃. Subsequently, the end hydroxyl groups of PCL‐N₃ were capped with ibuprofen as a model drug at room temperature. Finally, copper(I)‐catalyzed cycloaddition reaction between ibuprofen‐conjugated PCL‐N₃ and slightly excess alkyne‐terminated poly(ethylene glycol) (A‐PEG) led to ibuprofen‐conjugated A₂B₂ miktoarm star copolymer [(PCL)₂‐(PEG)₂‐D]. The excess A‐PEG was removed by dialysis. ¹H NMR, FTIR and SEC analyzes confirmed the expected miktoarm star architecture. These amphiphilic miktoarm star copolymers could self‐assemble into multimorphological aggregates in aqueous solution, which were characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). In addition, the drug‐loading capacity of these drug‐conjugated miktoarm star copolymers as well as their nondrug‐conjugated analogs were also investigated in detail. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2009     

Zr70Cu30非晶合金退火时结构弛豫过程的压力效应

 本文研究了Zr₇₀Cu₃₀非晶合金在压力下低于玻璃化温度退火时，表征结构中几何短程有序化过程的超导转变温度（T_c）的弛豫行为。结果表明，结构弛豫使T_c下降。压力退火则阻碍T_c的热弛豫下降趋势，但过程的动力学仍保持和常压弛豫相似的对数特征。作者应用压力促使非晶结构中局域张应力减小的观点来解释上述现象。     

Enhanced spin–orbit torque efficiency in Pt100−xNix alloy based magnetic bilayer

The binary alloy/ferromagnetic metal heterostructure has drawn extensive attention in the research field of spin–orbittorque(SOT)due to the potential enhancement of SOT efficiency via composition engineering.In this work,the magneticproperties and SOT efficiency in the Pt100?xNix/Ni78Fe22 bilayers were investigated via the spin-torque ferromagneticresonance(ST-FMR)technique.The effective magnetic anisotropy field and effective damping constant extracted by analyzing the ST-FMR spectra show a weak dependence on the Ni concentration.The effective spin-mixing conductanceof 8.40×10¹⁴??1·m?2and the interfacial spin transparency Tin of 0.59 were obtained for the sample of Pt70Ni30/NiFebilayer.More interestingly,the SOT efficiency that is carefully extracted from the angular dependence of ST-FMR spectrashows a nonmonotonic dependence on the Ni concentration,which reaches the maximum at x=18.The enhancement ofthe SOT efficiency by alloying the Ni with Pt shows potential in lowering the critical switching current.Moreover,alloyingrelatively cheaper Ni with Pt may promote to reduce the cost of SOT devices.     

Discovery potentials of double-charm tetraquarks

In this study, we investigate the discovery potential of double-charm tetraquarks \begin{document}$ T^{\{cc\}}_{[\bar{q}\bar{q}']} $\end{document}. We find that their production cross sections at the LHCb with \begin{document}$ \sqrt{s} = 13 $\end{document} TeV reach \begin{document}$ \mathcal{O}(10^4) $\end{document} pb, which indicates that the LHCb has collected \begin{document}$ \mathcal{O}(10^8) $\end{document} such particles. Through the decay channels of \begin{document}$ T^{\{cc\}}_{[\bar{u}\bar{d}]}\to D^{+}K^{-}\pi^{+} $\end{document} or \begin{document}$ D^0D^+\gamma $\end{document} (if stable) or \begin{document}$ T^{\{cc\}}_{[\bar{u}\bar{d}]}\to D^0D^{*+}\to D^0D^0\pi^+ $\end{document} (if unstable), it is highly expected that they get discovered at the LHCb in the near future. We also discuss the productions and decays of the double-charm tetraquarks at future Tera-\begin{document}$ Z $\end{document} factories.     

Avoiding Self-Reversed D Lines in Laser-Induced Breakdown Spectroscopy of Trace-Level Sodium in Soil

Journal of Applied Spectroscopy - Self-reversed sodium D lines in laser-induced plasmas generated from soil samples with a sodium trace concentration of 42.3 ppm was examined using laser-induced...