Structure Regulation of Electric Double Layer via Hydrogen Bonding Effect to Realize High-Stability Lithium-Metal Batteries

The interfacial chemistry of solid electrolyte interphases(SEI)on lithium(Li)electrode is directly determined by the structural chemistry of the electric double layer(EDL)at the interface.Herein,a strategy for regulating the structural chemistry of EDL via the introduction of intermolecular hydrogen bonds has been proposed(p-hydroxybenzoic acid(pHA)is selected as proof-of-concept).According to the molecular dynamics(MD)simulation and density functional theory(DFT)calculation results,the existence of hydrogen bonds realizes the anion structural rearrangement in the EDL,reduces the lowest unoccupied molecular orbital(LUMO)energy level of anions in the EDL,and the number of free solvent molecules,which promotes the formation of inorganic species-enriched SEI and eventually achieves the dendrite-free Li deposition.Based on this strategy,Li‖Cu cells can stably run over 185 cycles with an accumulated active Li loss of only 2.27 mAh cm^(-2),and the long-term cycle stability of Li‖Li cells is increased to 1200 h.In addition,the full cell pairing with the commercial LiFePO_(4)(LFP)cathodes exhibits stable cycling performance at 1C,with a capacity retention close to 90%after 200 cycles.

DFT Studies on the Isomerization of Butene Double Bond Catalyzed by 1-Butyl-3-methyl-imidazolium in Ionic Liquid

The geometries of reactant, product and transition state of the title reaction have been optimized by using density functional theory (DFT) at the B3LYP/6-31G(d,p) and B3LYP/6- 311++G(d,p) levels. The variations of the bond parameters in the course of reaction were analyzed. The zero point energy corrections were performed by vibrational analysis. The equilibrium states and the transition state were verified according to the number of virtue frequency of geometry. The intrinsic reaction coordinates (IRC) were calculated from the transition state. The calculated results show that the double bond rearrangement of butene catalyzed by 1-butyl-3-methyl-imidazolium cation is a one-step reaction. The forward energy barrier of isomerization from 1-butene to 2- butene is about 193 kJ·mol-1 and the reverse energy barrier about 209 kJ·mol-1 at the B3LYP/6- 31G(d,p) level, which means that the reaction is easy to proceed at or above room temperature.

Designer Mg-Mg and Zn-Zn Single Bonds Facilitated by Double Aromaticity in the M2B7^-(M=Mg,Zn)Clusters

The simple homodinuclear M-M single bonds for group II and XII elements are difficult to obtain as a result of the fulfilled s2electronic configurations,consequently,a dicationic prototype is often utilized to design the M^+-M^+single bond.Existing studies generally use sterically bulky organic ligands L^-to synthesize the compounds in the L^--M^+-M^+-L-manner.However,here we report the design of Mg-Mg and Zn-Zn single bonds in two ligandless clusters,Mg2B7-and Zn2B7-,using density functional theory methods.The global minima of both of the clusters are in the form of M2^2+(B7^3-),where the M-M single bonds are positioned above a quasi-planar hexagonal B7 moiety.Chemical bonding analyses further confirm the existence of Mg-Mg and Zn-Zn single bonds in these clusters,which are driven by the unusually stable B7^3-moiety that is bothσandπaromatic.Vertical detachment energies of Mg2B7-and Zn2B7-are calculated to be 2.79 e V and 2.94 e V,respectively,for the future comparisons with experimental data.

Theoretical study on non-sequential double ionization of carbon disulfide with different bond lengths in linearly polarizedlaser fields

By using a two-dimensional Monte-Carlo classical ensemble method, we investigate the double ionization（DI） process of the CS_2 molecule with different bond lengths in an 800-nm intense laser field. The double ionization probability presents a ＂knee＂ structure with equilibrium internuclear distance R = 2.9245 a.u.（a.u. is short for atomic unit）. As the bond length of CS increases, the DI probability is enhanced and the ＂knee＂ structure becomes less obvious. In addition,the momentum distribution of double ionized electrons is also investigated, which shows the momentum mostly distributed in the first and third quadrants with equilibrium internuclear distance R = 2.9245 a.u. As the bond length of CS increases,the electron momentum becomes evenly distributed in the four quadrants. Furthermore, the energy distributions and the corresponding trajectories of the double-ionized electrons versus time are also demonstrated, which show that the bond length of CS in the CS_2 molecule plays a key role in the DI process.

LOCATION OF DOUBLE BOND POSITION OF INSECT SEX PHEROMONE BY GC/MS ANALYSIS WITH CHEMICAL IONIZATION

Ozonolysis products of four lepidopteral pheromone were identified by methane CI-MS.The spectra obtained were notably simpler than those of EI-MS,the peak of molecular ion was normally close to the base peak,and the characteristic fragment ions were high in m/z,thereby the interpretation was facilitated.

IDENTIFICATION OF DOUBLE BOND POSITION IN HEXADECENYL ACETATES BY MASS SPECTROMETRY

A method for locating double bond in hexadecenyl acetates has been developed by analyzing the mass spectral patterns on a fuzzy classification. The procedure was tested with the spectra of Δ~2- to Δ^(15)-isomers and the original double-bond position in these acetates was located unambiguously.

Syntheses and Crystal Structures of Two New One-dimensional Double Hydrogen-bonding-chain Complexes [Ni(bipy)_2Cl]·ClO_4 and [Zn(bipy)_2Cl]·BF_4

Two new transition metal complexes, [Ni（bipy）2Cl]·ClO4 （bipy = 2,2＇-bipyridine） 1 and [Zn（bipy）2Cl]·BF4 2, have been synthesized and characterized by single-crystal X-ray diffraction analysis. Both 1 and 2 crystallize in monoclinic space group P21/n with Z = 4. For 1, a = 10.776（1）, b = 12.067（1）, c = 16.146（2）A, β = 93.021（2）o, V = 2031.9（4） A^3, Mr = 505.98, Dc = 1.654 g/cm^3, μ = 1.255 mm^–1, F（000） = 1032, the final R = 0.0406 and wR = 0.1002 for 3983 observed reflections with Ⅰ 〉 2σ（Ⅰ）. For 2, a = 10.758（4）, b = 12.058（4）, c = 16.135（5） A, β = 104.57（1）o, V = 2025.7（12） A^3, Mr = 500.00, Dc = 1.639 g/cm^3, μ = 1.396 mm^–1, F（000） = 1008, the final R = 0.0470 and wR = 0.1237 for 3759 observed reflections with Ⅰ 〉 2σ（Ⅰ）. The crystal structures of 1 and 2 are isostructural with very similar supramolecular structures. A one-dimen-sional zigzag double hydrogen-bonding-chain is generated by the intermolecular M-bipy ···anion···bipy- M hydrogen bonding interactions between the chelating ligands of bipy and anion.

Synthesis and Structural Characterization of a New Cadmium(II) Complex with a Double Betaine

A new flexible double betaine L （L = 1,4-bis（pyridinio-4-carboxylato-N-methyl）benzene, C20H16N2O4） and its cadmium（Ⅱ） complex [Cd（H2O）aL（NO3）]NO3.H2O 1 were synthesized. Complex 1 was obtained by self-assembly reaction of [Cd（NO3）2]-4H2O and L in hot water,and its crystal structure was determined by single-crystal X-ray diffraction analysis. Crystallographic data for complex 1： C20H24CdN4O14.H2O, Mr = 674.85, monoclinic, space group P21/c, a =13.7854（3）, b = 14.2820（3）, c = 14.9188（4） ,A°, β = 116.418（1）°, V = 2630.5（1）A°^3, Z = 4, Dc= 1.704g/cm^3,/J（MoKα） = 0.911 mm^-1, F（000） = 1368, the final R = 0.0315 and wR = 0.0768 for 3637 observed reflections with I 〉 2σ（I）. In complex 1, L acts as a monodentate ligand to link a Cd（Ⅱ） ion in a novel coordination mode of double betaines. The mononuclear [Cd（H2O）aL（NO3）] units are connected through intermolecular hydrogen bonds and π-π stacking reactions to generate a 3D network.

Microstructure of nickel foam/Mg double interpenetrating composites

The magnesium matrix double interpenetrating composites reinforced by nickel foam were fabricated by pressureless infiltration technology.Then the morphology of the nickel reinforcement and the microstructures of composites were characterized by SEM.The results show that not only is the nickel foam reinforcement reticular in three dimensions,but also the struts of foam keep the network structure,which ensures that the Ni foam/Mg composites are double interpenetrating.The interface bonding of composites between magnesium matrix and nickel foam reinforcement is good,without reaction around the interface,which is the indispensable condition that advanced composites should possess.Magnesium matrix distributes in the windows of nickel foam,the triangle center holes and microhole of nickel struts,and the composites have double interpenetrating structure,which makes the composites have unique properties.

基于Multi-stage的double stitch工艺在铜线焊中的应用

作为引线键合工艺中传统的焊接材料,金线在稳定性、导电性及价格等方面存在诸多局限,使得铜线焊技术在IC封装领域得到越来越广泛的应用。同时,由于铜线易氧化、硬度高,焊接能力较低,特别是二焊点容易出现拉力不够、开裂等缺陷,使得铜线焊的应用受到限制。针对传统工艺流程,提出Multi-stage方法,并在此基础上实现二焊点的double stitch工艺方法,通过试验证明该方法能够有效提高二焊点拉力,增强焊接强度。

A FACILE SYNTHESIS OF 2-TRIFLUOROMETHYLPYRROLE VIA 1,3-DIPOLAR CYCLOADDITION REACTION OF 2-TRIFLUOROMETHYLOXAZOLONE AND THE ACTIVATED CARBON-CARBON MULTIPLE BOND

The 1.3-dipolar cycloaddition reaction of 2-trifluoromethyl- oxazolone and the activated carbon-carbon multiple bond was studied and gave a convenient way to synthesize 2-trifluoromethylpyrrole derivatives.

Biomass valorization via electrocatalytic carbon–carbon bond cleavage

Renewable electrocatalytic upgrading of biomass feedstocks into valuable chemicals is one of the promising strategies to relieve the pressure of traditional energy-based systems.Through electrocatalytic carbon–carbon bond cleavage of high selectivity,various functionalized molecules,such as organic acids,amides,esters,and nitriles,have great potential to be accessed from biomass.However,it has merely received finite concerns and interests in the biorefinery.This review first showcases the research progress on the electrocatalytic conversion of lipid/sugar-and lignin-derived molecules(e.g.,glycerol,mesoerythritol,xylose,glucose,1-phenylethanol,and cyclohexanol)into organic acids via specific carbon–carbon bond scission processes,with focus on disclosing reaction mechanisms,recognizing actual active species,and collecting feasible modification strategies.For the guidance of further extensive studies on biomass valorization,organic transformations via a variety of reactions,including decarboxylation,ring-opening,rearrangement,reductive hydrogenation,and carboxylation,are also disclosed for the construction of similar carbon skeletons/scaffolds.The remaining challenges,prospective applications,and future objectives in terms of biomass conversion are also proposed.This review is expected to provide references to develop renewed electrocatalytic carbon–carbon bond cleavage transformation paths/strategies for biomass upgrading.

Highly Efficient Oxidative Cleavage of Carbon-Carbon Double Bond over meso-Tetraphenyl Cobalt Porphyrin Catalyst in the Presence of Molecular Oxygen

Highly efficient and selective carbon-carbon double bond aerobic cleavage of olefins catalyzed by metallopor- phyrins was investigated, and carbonyl compounds and epoxide were produced as the main products. CoTPP （co- balt meso-tetraphenyl porphyrin） showed excellent activity for the oxidative cleavage of carbon-carbon double bond by using styrene as model compound, in which the TOF （turnover frequency） and selectivity toward benzaldehyde was obtained with 2×10^4h-1 and 86%,respectively.

基于bonding技术的负载均衡研究

负载均衡技术的使用能够扩展网络设备和服务器的带宽、增加吞吐量、加强网络数据处理能力、提高网络的灵活性和可用性。文章阐述了基于bonding技术的负载均衡思想,描述了Linux bonding驱动的加载步骤,并利用测试带宽工具在Linux平台双网卡连接环境下对bonding技术的性能进行测试,并对测试结果进行分析,表明bonding技术在负载均衡方面的可用性。

On Female Bonding in Sula

In Toni Morrison’s controversial novel Sula,she mainly deals with the issue of black women. With the guide of black feminist perspective of Barbara Smith,i.e. the politics of race and the politics of sex,the female bonding is an efficient approach to the analysis of women’s problem. Men are excluded from the women’s bonding which has many forms and functions.

Introducing an Extended Covalent Bond between Oxygen Atoms with an OXO-Shape in Ions and Molecules: Compatibility with the Even-Odd and the Isoelectronicity Rules

Building on the recent success of the even-odd rule, the present paper explores its implications by studying the very specific case of OXO compounds. These compounds are usually represented with double bonds linking two oxygen atoms to a central atom—as in carbon dioxyde—yet can sometimes be drawn in a triangular structure, such as in calcium dioxyde. Measurement data moreover indicate that most OXO compounds have an angle around 120° between oxygen atoms, although that seems incompatible with triangular representations. The aim here is to unify these commonly admitted representations by linking oxygen atoms through a single bond that is longer than usual covalent bonds: an “elongated bond”. This elongated bond has the interesting effect of suppressing the need for double bonds between oxygen and the central atom. The elongated bond concept is applied to about a hundred of molecules and ions and methodically compared to classical representations. It is shown that this new representation, associated to the even-odd rule, is compatible with all studied compounds and can be used in place of their classical drawings. Its usage greatly simplifies complex concepts like resonance and separated charges in gases. Elongated bonds are also shown to be practicable with the isoelectronic rule as well as isomers, and throughout chemical reactions. This study of an especially long and wide angle bond confirms the versatility of the even-odd rule: it is not limited to compounds with short covalent bonds and can include OO covalent bond lengths of more than 200 pm and with OXO angles above 90°.

REQUIREMENT OF SILICON FLATNESS FOR SILICON DIRECT BONDING TECHNOLOGY

The influence of silicon slice flatness on bonding technology and the relation between a foreign particle and resulting bubble are quantitatively presented by the elastic theory. It is demonstrated experimentally by X-ray double crystal diffractometry and infrared imager.

茂金属聚乙烯薄膜晶点的组成及形成原因

采用凝胶渗透色谱仪(GPC)、差示扫描量热仪(DSC)、偏光显微镜以及红外光谱等分析手段,从原料的分子链结构分析了茂金属聚乙烯薄膜晶点的组成及其形成原因。结果表明,茂金属聚乙烯薄膜晶点的结晶形态与无晶点的正常薄膜的不同,构成晶点的晶体尺寸均匀性远不如无晶点的正常薄膜,这是因为晶点中含有类似于纤维状的晶体,这种晶体先结晶,导致随后形成的晶体在此处生长不均匀。此外,分子链上的端基双键(RCH CH 2)在吹膜过程中引起的分子间交联和分子链中存在的亚甲基序列较长的规整结构,是形成类纤维状晶体的主要因素,而较长亚甲基序列的规整结构是由于共聚单体分布不均匀引起的。

轨道减振器双底模注射硫化成型工艺的研究与应用

对轨道减振器双底模注射硫化成型工艺进行研究,并与传统高压模硫化成型工艺进行对比。结果表明:双底模注射成型工艺缩短了硫化时间,实现了轨道减振器的连续化生产,同时提高了型腔内压,促进了金属与橡胶的有效粘接;双底模注射硫化成型轨道减振器疲劳后垂向静刚度和动静刚度比变化率小,垂向静刚度波动范围在10%以内,产品性能更稳定。

不同光引发剂口腔复合树脂单体的设计合成及性能

背景:目前由树脂基质单体组成的牙科复合树脂充填物,是牙体缺损充填治疗的首选材料,但随着其在口腔环境中使用时间的延长,牙体组织继发龋以及充填材料磨损折断等问题随之而来,造成这些问题的主要原因是充填材料的聚合收缩及其与牙体组织的机械性能不匹配等。目的:通过加入不同组分的引发剂合成牙科新型复合树脂单体,以提升传统体系的双键转化率并进一步提高材料的力学性能。方法:将不同的引发剂加入3,3′,5,5′-四甲基联苯二酚型环氧丙烯酸酯树脂单体中,制备新型复合树脂基质体系:A组加入质量分数1.1%的樟脑醌,B组加入质量分数2.1%的1-苯基-1,2-丙二酮,C组加入质量分数3.1%的樟脑醌与1-苯基-1,2-丙二酮混合物(二者质量比为1∶1)。检测各组样品的双键转化率、聚合收缩率和机械性能。结果与结论:①B、C组双键转化率高于A组(P<0.05);B组聚合收缩率大于A组(P<0.05),C组聚合收缩率小于A组(P<0.05);②B、C组的挠曲强度、弹性模量、压缩强度均大于A组(P<0.05,P<0.01),B组的维氏硬度大于A组(P<0.05),C组的维氏硬度小于A组(P<0.01);③结果显示,1-苯基-1,2-丙二酮是一种性能较理想的引发剂,且1-苯基-1,2-丙二酮与樟脑醌联合应用可有效提高树脂基质体系的双键转化率,从而提高树脂的力学性能。