Thom-Sebastiani properties of Kohn-Rossi cohomology of compact connected strongly pseudoconvex CR manifolds

Let X_1 and X_2 be two compact connected strongly pseudoconvex embeddable Cauchy-Riemann(CR) manifolds of dimensions 2m-1 and 2n-1 in C~(m+1)and C~(n+1), respectively. We introduce the ThomSebastiani sum X = X_1 ⊕X_2which is a new compact connected strongly pseudoconvex embeddable CR manifold of dimension 2m+2n+1 in C~(m+n+2). Thus the set of all codimension 3 strongly pseudoconvex compact connected CR manifolds in Cn+1for all n 2 forms a semigroup. X is said to be an irreducible element in this semigroup if X cannot be written in the form X_1 ⊕ X_2. It is a natural question to determine when X is an irreducible CR manifold. We use Kohn-Rossi cohomology groups to give a necessary condition of the above question. Explicitly,we show that if X = X_1 ⊕ X_2, then the Kohn-Rossi cohomology of the X is the product of those Kohn-Rossi cohomology coming from X_1 and X_2 provided that X_2 admits a transversal holomorphic S~1-action.     

Understanding the accumulated cycle capacity fade caused by the secondary particle fracture of LiNi<Subscript>1-x-y</Subscript>Co<Subscript>x</Subscript>Mn<Subscript>y</Subscript>O<Subscript>2</Subscript> cathode for lithium ion batteries

Effect of secondary particle fracture on the accumulated cycle capacity fade of LiNi_1-x-yCo_xMn_yO₂ cathode is difficult to evaluate since performance degradation of electrode material is always caused by several factors simultaneously. Herein, LiNi_0.5Co_0.2Mn_0.3O₂ single particles (Sin-P) are prepared and introduced as a reference to understand the accumulated cycle capacity fade caused by the secondary particle fracture of LiNi_0.5Co_0.2Mn_0.3O₂ secondary particles (Sec-P). Sec-P exhibited accumulated cycle capacity fade compared to Sin-P when cycled at high rate, high voltage, and high temperature. The accumulated cycle capacity fade was mainly caused by the secondary particle fracture of Sec-P, which was confirmed by the X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscope (SEM) analysis. Further, XPS and electrochemical impedance spectroscopy (EIS) analysis indicated that the surface property changes and resistance rise were responsible for the accumulated cycle capacity fade. The study provides a novel way to analyze the accumulated cycle capacity fade caused by the secondary particle fracture and is helpful for understanding the performance degradation mechanism of electrode material.     

Rogue waves in baroclinic flows

We investigate an AB system, which can be used to describe marginally unstable baroclinic wave packets in a geophysical fluid. Using the generalized Darboux transformation, we obtain higher-order rogue wave solutions and analyze rogue wave propagation and interaction. We obtain bright rogue waves with one and two peaks. For the wave packet amplitude and the mean-flow correction resulting from the self-rectification of the nonlinear wave, the positions and values of the wave crests and troughs are expressed in terms of a parameter describing the state of the basic flow, in terms of a parameter responsible for the interaction of the wave packet and the mean flow, and in terms of the group velocity. We show that the interaction of the wave packet and mean flow and also the group velocity affect the propagation and interaction of the amplitude of the wave packet and the self-rectification of the nonlinear wave.     

Selection of hydrogel electrolytes for flexible zinc–air batteries

Flexible zinc–air batteries attract more attention due to their high energy density, safety, environmental protection, and low cost. However, the traditional aqueous electrolyte has the disadvantages of leakage and water evaporation, which cannot meet application demand of flexible zinc–air batteries. Hydrogels possessing good conductivity and mechanical properties become a candidate as the electrolytes of flexible zinc–air batteries. In this work, advances in aspects of conductivity, mechanical toughness, environmental adaptability, and interfacial compatibility of hydrogel electrolytes for flexible zinc–air batteries are investigated. First, the additives to improve conductivity of hydrogel electrolytes are summarized. Second, the measures to enhance the mechanical properties of hydrogels are taken by way of structure optimization and composition modification. Third, the environmental adaptability of hydrogel electrolytes is listed in terms of temperature, humidity, and air composition. Fourth, the compatibility of electrolyte–electrode interface is discussed from physical properties of hydrogels. Finally, the prospect for development and application of hydrogels is put forward.     

Syntheses,crystal structures and magnetic properties of two new cyano-bridged bimetallic complexes

Transition Metal Chemistry - Two complexes [Fe(1,10-phen)2Ni(CN)4]n (1), {[Fe2(1,10-phen)4(CN)4Co2(1,10-phen)2Fe(CN)6]·2H2O}n (2) were prepared in the reaction of K3[Fe(CN)6] as cyanometalate...     

高温下HBT晶体热分解过程的理论模拟

基于自洽电荷密度泛函紧束缚(SCC-DFTB)方法研究了富氮含能材料5, 5’-双四唑肼(C₂H₄N₁₀, HBT)晶体在高温下的热分解反应过程.结果表明,结构优化参数与实验误差在5%以内.在2000 K, 2500 K,和3000 K不同温度下,HBT晶体热分解路径和产物表现出相似性.通过过渡态理论和分子动力学两种方法,研究了分解反应C₂H₄N₁₀→C₂H₃N₇+HN₃,发现HBT晶体分解产物中存在叠氮酸(HN₃)分子,化学反应势垒高度为222.85 kJ·mol^-1.研究结果为进一步理解高温下HBT晶体热分解特征提供理论参考.     

柠檬酸配合法制备CuMnCeOx催化剂及常温催化氧化性能研究

摘要：常温催化氧化是消除室内HCHO污染最可行的方法之一,其中以过渡金属氧化物为代表的催化剂因性能优异、成本低廉而备受广泛关注。采用柠檬酸络合法和水热法制备了一系列CuMnCeOx催化剂,研究考察制备方法及载体对催化剂氧化性能的影响,并利用XRD、SEM、BET、H2-TPR、XPS和IR等对催化剂进行微观表征与分析。研究发现,制备方法及载体类型对催化剂的表面结构形貌、氧化性能产生显著影响,其中采用柠檬酸络合法所制的CuMnCeOx-C催化剂性能最佳,48h的HCHO去除率达98.6%,完全满足GB50325-2001标准要求,其介孔结构,晶体粒径及所形成的铈基铜锰固溶体均利于形成大量氧空位及催化氧化反应,且展示出良好的抗水蒸气和稳定性能,其在常温催化氧化VOCs方面具有重要应用前景。     

有限元网格自动生成及自动调整技术

本文给出了一种任意平面域内三角形网格自动生成及自动调整算法，并编制了相应的程序。通过对带Ｕ形槽的三点变曲试件的分析，证明本文算法是可行的，并且具有稳定性能好、收敛速度快的优点。     

钢纤混凝土裂纹尖端应变场的实验研究

本文应用散斑干涉技术在四组含纤量分别为０，０．５％，１％，１．５％的钢纤混凝土三点弯曲裂纹试件的裂纹尖端位移场进行了测试，并换算为应变场。对钢纤混凝土开裂的基理进行了探讨；验证了最大位应变准则；并测定断裂韧度Ｊｉｃ．     

磁粉法检测表面裂纹概率曲线的测定

本文介绍了利用实物零件测定裂纹检出概率的方法，并作出了用磁粉法检测表面裂纹的检测概率曲线，为大型构件检测周期的确定提供了可靠数据，为结构损伤容限设计，可靠性设计提供了重要的依据。