Unsaturated bi-heterometal clusters in metal-vacancy sites of 2D MoS2 for efficient hydrogen evolution

The valence states and coordination structures of doped heterometal atoms in two-dimensional(2D)nanomaterials lack predictable regulation strategies.Hence,a robust method is proposed to form unsaturated heteroatom clusters via the metal-vacancy restraint mechanism,which can precisely regulate the bonding and valence state of heterometal atoms doped in 2D molybdenum disulfide.The unsaturated valence state of heterometal Pt and Ru cluster atoms form a spatial coordination structure with Pt–S and Ru–O–S as catalytically active sites.Among them,the strong binding energy of negatively charged suspended S and O sites for H+,as well as the weak adsorption of positively charged unsaturated heterometal atoms for H*,reduces the energy barrier of the hydrogen evolution reaction proved by theoretical calculation.Whereupon,the electrocatalytic hydrogen evolution performance is markedly improved by the ensemble effect of unsaturated heterometal atoms and highlighted with an overpotential of 84 mV and Tafel slope of 68.5 mV dec^(−1).In brief,this metal vacancy-induced valence state regulation of heterometal can manipulate the coordination structure and catalytic activity of heterometal atoms doped in the 2D atomic lattice but not limited to 2D nanomaterials.

Gut microbiota in women:The secret of psychological and physical well-being

The gut microbiota works in unison with the host,promoting its health.In particular,it has been shown to exert protective,metabolic and structural functions.Recent evidence has revealed the influence of the gut microbiota on other organs such as the central nervous system,cardiovascular and the endocrine-metabolic systems and the digestive system.The study of the gut microbiota is outlining new and broader frontiers every day and holds enormous innovation potential for the medical and pharmaceutical fields.Prevention and treatment of specific women’s diseases involves the need to deepen the function of the gut as a junction organ where certain positive bacteria can be very beneficial to health.The gut microbiota is unique and dynamic at the same time,subject to external factors that can change it,and is capable of modulating itself at different stages of a woman’s life,playing an important role that arises from the intertwining of biological mechanisms between the microbiota and the female genital system.The gut microbiota could play a key role in personalized medicine.

Resonant Auger Scattering by Attosecond X-Ray Pulses

As x-ray probe pulses approach the subfemtosecond range,conventional x-ray photoelectron spectroscopy(XPS)is expected to experience a reduction in spectral resolution due to the effects of the pulse broadening.However,in the case of resonant x-ray photoemission,also known as resonant Auger scattering(RAS),the spectroscopic technique maintains spectral resolution when an x-ray pulse is precisely tuned to a core-excited state.We present theoretical simulations of XPS and RAS spectra on a showcased CO molecule using ultrashort x-ray pulses,revealing significantly enhanced resolution in the RAS spectra compared to XPS,even in the subfemtosecond regime.These findings provide a novel perspective on potential utilization of attosecond x-ray pulses,capitalizing on the well-established advantages of detecting electron signals for tracking electronic and molecular dynamics.

A leap by the rise of solid-state electrolytes for Li-air batteries

Li-air batteries have attracted extensive attention because of their ultrahigh theoretical energy density. However, the potential safety hazard of flammable organic liquid electrolytes hinders their practical applications. Replacing liquid electrolytes with solidstate electrolytes(SSEs) is expected to fundamentally overcome the safety issues. In this work, we focus on the development and challenge of solid-state Li-air batteries(SSLABs). The rise of different types of SSEs, interfacial compatibility and verifiability in SSLABs are presented. The corresponding strategies and prospects of SSLABs are also proposed. In particular, combining machine learning method with experiment and in situ(or operando)techniques is imperative to accelerate the development of SSLABs.

MLD-MPC Approach for Three-Tank Hybrid Benchmark Problem

The present paper aims at validating a Model Predictive Control(MPC),based on the Mixed Logical Dynamical(MLD)model,for Hybrid Dynamic Systems(HDSs)that explicitly involve continuous dynamics and discrete events.The proposed benchmark system is a three-tank process,which is a typical case study of HDSs.The MLD-MPC controller is applied to the level control of the considered tank system.The study is initially focused on the MLD approach that allows consideration of the interacting continuous dynamics with discrete events and includes the operating constraints.This feature of MLD modeling is very advantageous when an MPC controller synthesis for the HDSs is designed.Once the MLD model of the system is well-posed,then the MPC law synthesis can be developed based on the Mixed Integer Programming(MIP)optimization problem.For solving this MIP problem,a Branch and Bound(B&B)algorithm is proposed to determine the optimal control inputs.Then,a comparative study is carried out to illustrate the effectiveness of the proposed hybrid controller for the HDSs compared to the standard MPC approach.Performances results show that the MLD-MPC approach outperforms the standardMPCone that doesn’t consider the hybrid aspect of the system.The paper also shows a behavioral test of the MLDMPC controller against disturbances deemed as liquid leaks from the system.The results are very satisfactory and show that the tracking error is minimal less than 0.1%in nominal conditions and less than 0.6%in the presence of disturbances.Such results confirm the success of the MLD-MPC approach for the control of the HDSs.

表面改性处理钛增强纤维连接蛋白介导的成骨细胞MG-63黏附和增殖(英文)

采用化学抛光处理钛、阳极氧化和微弧氧化处理钛作为生物材料模型,研究成骨细胞MG-63在其表面的黏附和增殖机理。结果表明,阳极氧化和微弧氧化处理的钛表面通过促进MG-63细胞分泌纤维连接蛋白形成细胞外基质从而使其快速附着和伸展。另外,阳极氧化和微弧氧化处理的钛表面通过Outside-in信号传导通路,上调纤维连接蛋白及与其相关的整合素α5的转录水平,促进成骨细胞MG-63在其表面的增殖。

Co-Mn-Ni-O_2系材料阻温特性与频率关系的研究

通过XRD、SEM分析和变温、变频条件下的lgρ-t测量,对Co-Mn-Ni-O2系热敏材料的lgρ-t特性与频率f的关系进行了研究。结果表明:CoMn1.4Ni0.6O4尖晶石型氧化物热敏电阻材料的阻温特性在0.1~1MHz和–70^+100℃,发生了PTC向NTC的转变,且转变点的温度(–70~–10℃)和f(0.1~1MHz)与材料电阻率ρ有关。根据电导率σ和载流子浓度n、载流子迁移率μ之间的关系,用小极子跳跃导电理论对上述现象作了解释。

动力电池组液冷散热系统

设计一种车用动力电池组的液冷系统,系统由R134a蒸汽压缩制冷回路和乙二醇水溶液循环回路两部分组成。其中制冷剂回路和冷却液回路在板式蒸发器处耦合,冷却液通过布置于电池组两侧的冷板对电池冷却。建立一维稳态制冷回路、冷却液回路和电池组的仿真模型,并开展相关温控实验。结果表明电池组最高温度受放电电流影响。在1 C及以下倍率工作时,液冷系统能稳定控制电池组处在适宜的工作温度范围内且温度均衡。

Could metabolic syndrome lead to hepatocarcinoma via non-alcoholic fatty liver disease?

It was estimated that from 2002 to 2008 the risk of developing cancer increased a quarter-fold in men and twofold in women due to excessive BMI.Obesity,metabolic syndrome and type 2 diabetes mellitus are strictly related and are key pathogenetic factors of non-alcoholic fatty liver disease(NAFLD),the most frequent liver disease worldwide.The most important consequence of the"metabolic epidemics"is the probable rise in the incidence of hepatocarcinoma(HCC),and NAFLD is the major causative factor.Adipose tissue is not merely a storage organ where lipids are preserved as an energy source.It is an active organ with important endocrine,paracrine,and autocrine actions in addition to immune functions.Adipocytes produce a wide range of hormones,cytokines,and growth factors that can act locally in the adipose tissue microenvironment and systemically.In this article,the main roles of insulin growth factor(IGF)-1 and IGF-2 are discussed.The role of IGF-2 is not only confined to HCC,but it may also act in early hepato-carcinogenesis,as preneoplastic lesions express IGF-2 mRNA.IGF-1 and IGF-2interact with specific receptors(IGF-1R and IGF-2R).IGF-1R is over-expressed in in vitro and in animal models of HCC and it was demonstrated that IGF ligands exerted their effects on HCC cells through IGF-1R and that it was involved in the degeneration of pre-neoplastic lesions via an increase in their mitotic activity.Both IGF-2R and TGFβ,a growth inhibitor,levels are reduced in human HCC compared with adjacent normal liver tissues.Another key mechanism involves peroxisome proliferator-activated receptor(PPAR)γ.In in vitro studies,PPARγinhibited various carcinomas including HCC,most probably by regulating apoptosis via the p21,p53 and p27 pathways.Finally,as a clinical consequence,to improve survival,efforts to achieve a"healthier diet"should be promoted by physicians and politicians.

通过直接S型电荷转移和高度改进的可见光驱动光催化效率构建3D花状O-掺杂g-C_(3)N_(4)-[N-掺杂Nb_(2)O_(5)/C]异质结

通过将两种光催化材料复合构建合适的异质结构光催化体系,可设计出广泛应用于环境、医疗和能源领域的高效光催化剂.近年来,S型异质结体系因可实现高效的光生载流子分离,同时表现出较强的光氧化还原能力而备受关注.本文通过超声和剧烈搅拌的方法构建了由2D O-掺杂g-C_(3)N_(4)(OCN)纳米片和3D N-掺杂Nb_(2)O_(5)/C(N-NBO/C)纳米花组成的新型S型异质结体系,经过热处理后用于罗丹明B(RhB)的光催化降解.实验结果表明,优化的4OCN-[N-NBO/C](OCN和N-NBO/C含量分别为40 mg和100 mg)样品表现出较好的理化特性,其比表面积大、载流子的分离效率高、可见光吸收效率大和紧邻接触面大.EPR试验和自由基捕获实验结果表明,OCN和N-NBO/C之间形成了S型异质结.RhB光催化降解实验结果表明,在可见光照射下,所制备的材料表现出较好的催化性能,催化剂光催化效率高,稳定性好.光催化降解性能的提高可归因于快速电荷转移、高效电荷分离、光致电荷载流子的寿命延长以及S型体系中光致电荷的高氧化还原能力.本文还深入研究了催化剂的组成、结构、形貌以及RhB的光催化降解机制,为相关研究提供了一定参考.

可靠性、可用性与可维修性分析在LNG接收站产能预测中的应用(英文)

LNG设施通常包括天然气液化、LNG储运及运输等。在中国天然气供应链对经济民生影响重大。天然气供应链或供应系统中关键设备的非计划及计划性维修导致的天然气供应中断,都可能造成巨大的经济损失。本项目应用可靠性、可用性及可维修性(RAM)分析方法对于液化天然气储备库及附属设施的可靠性指标进行评估,定量分析LNG供应链中关键设备的失效及维修时间对于整个供应链可靠性指标的影响。RAM分析可以用来预测在指定的运行周期内整个LNG供应链的运行绩效。RAM分析辨识关键设备的失效模式,确定失效数据,并采取Monte Carlo的模拟计算,获得LNG供应链或系统中,关键设备失效对于可靠性指标影响。本文通过国内某LNG储备库项目的 RAM分析,应用以Monte Carlo模拟为基础的系统可靠性分析软件ReliaSuite?,评估LNG储备库系统设计能否满足可靠性指标。并且对LNG储运设施的卸料臂进行了失效模式及关键性影响分析(FMECA)。通过对LNG储备库各子系统对于项目整体可靠性的贡献进行敏感性分析,找到影响项目整体可靠性的瓶颈及解决方案。

在役LNG接收站的SIS系统再验证

广东大鹏LNG接收站作为中国最早投用的LNG接收站,在5年的高负荷运行后中新增并改造了部分设备及功能安全回路(SIF),为确保接收站功能安全仪表系统(SIS)的完整性与可靠性以及高负荷生产的可用性,对所有生产设施及管线场站进行了HAZOP分析,并在HAZOP分析的基础上进行了SIL定级及再验证(re-validation)工作。本文以SIL再验证工作为例介绍SIL验算/再验证在在役装置中的应用,以及如何通过敏感性分析优化SIS系统配置与校验管理,满足企业风险可接受标准,最后总结并展望了实施SIL验算工作中的技术难点和未来的技术方向。

SYNTHESIS OF AN EPOXY-TERMINATED HYPERBRANCHED AROMATIC POLYESTER

An epoxy-terminated hyperbranched aromatic polyester (P3) was synthesized from a hyperbranched aromatic polyester containing carboxylic acid end groups (P1), which was derived from the condensation polymerization of the AB(2) monomer, 5-acetoxyisophthalic acid. Polymer P1 was converted into the polymeric acid chloride by reaction with thionyl chloride. The acid chloride was reacted with ethanol and glycidol to form a poly(ethyl ester) (P2) and an epoxy terminated material (P3), respectively. The reaction conditions in each step of these processes had to be controlled very carefully to avoid unwanted cross-linking reactions. The characterization of products and intermediates, including molecular weight distributions and thermal properties, are reported.

Nonalcoholic fatty liver disease, spleen and psoriasis:New aspects of low-grade chronic inflammation

AIM: To investigate spleen status in psoriasis and itsrelationship with hepatic steatosis, Psoriasis Area and Severity Index, and insulin resistance.METHODS: Seventy-nine psoriatic patients who were not suffering from any chronic inflammatory disease were retrospectively selected for inclusion in this study,and their complete medical records were accessed.An age- and sex-matched group of 80 non-psoriatic,obese patients was included as a control. The following relevant data were collected: age, sex, weight, height,body mass index, waist circumference, blood pressure,insulin resistance status, age at psoriasis onset, and severity of psoriasis. Abdominal ultrasonography was performed to determine spleen longitudinal diameter(SLD), and hepatic steatosis grade.RESULTS: The SLD of control obese patients was greater than that of psoriatic subjects(P = 0.013),but body mass index predicted the size of the spleen in psoriatic patients(P < 0.001). The SLD of psoriatic patients with normal weight was significantly reduced with respect to the overweight/obese psoriatic patients(P = 0.002). A multiple regression analysis revealed that body mass index was a unique predictor of the spleen size(P < 0.001). Finally, the disease duration predicted the spleen size in psoriatic subjects(P =0.038).CONCLUSION: This study shows a correlation between the SLD and the duration of psoriasis.

Core-Excited Molecules by Resonant Intense X-Ray Pulses Involving Electron-Rotation Coupling

It has been reported that electron-rotation coupling plays a significant role in diatomic nuclear dynamics induced by intense VUV pulses [Phys. Rev. A 102(2020) 033114;Phys. Rev. Res. 2(2020) 043348]. As a further step, we present here investigations of the electron-rotation coupling effect in the presence of Auger decay channel for core-excited molecules, based on theoretical modeling of the total electron yield(TEY), resonant Auger scattering(RAS) and x-ray absorption spectra(XAS) for two showcases of CO and CH^(+) molecules excited by resonant intense x-ray pulses. The Wigner D-functions and the universal transition dipole operators are introduced to include the electron-rotation coupling for the core-excitation process. It is shown that with the pulse intensity up to 10^(16) W/cm^(2), no sufficient influence of the electron-rotation coupling on the TEY and RAS spectra can be observed. This can be explained by a suppression of the induced electron-rotation dynamics due to the fast Auger decay channel, which does not allow for effective Rabi cycling even at extreme field intensities,contrary to transitions in optical or VUV range. For the case of XAS, however, relative errors of about 10% and 30% are observed for the case of CO and CH^(+), respectively, when the electron-rotation coupling is neglected.It is concluded that conventional treatment of the photoexcitation, neglecting the electron-rotation coupling,can be safely and efficiently employed to study dynamics at the x-ray transitions by means of electron emission spectroscopy, yet the approximation breaks down for nonlinear processes as stimulated emission, especially for systems with light atoms.

Classification of Images Based on a System of Hierarchical Features

The results of the development of the new fast-speed method of classification images using a structural approach are presented.The method is based on the system of hierarchical features,based on the bitwise data distribution for the set of descriptors of image description.The article also proposes the use of the spatial data processing apparatus,which simplifies and accelerates the classification process.Experiments have shown that the time of calculation of the relevance for two descriptions according to their distributions is about 1000 times less than for the traditional voting procedure,for which the sets of descriptors are compared.The introduction of the system of hierarchical features allows to further reduce the calculation time by 2–3 times while ensuring high efficiency of classification.The noise immunity of the method to additive noise has been experimentally studied.According to the results of the research,the marginal degree of the hierarchy of features for reliable classification with the standard deviation of noise less than 30 is the 8-bit distribution.Computing costs increase proportionally with decreasing bit distribution.The method can be used for application tasks where object identification time is critical.

镍铬和氮化钽膜电阻在通信应用中的比较

通信产业的成功依赖于通信服务的可靠性,然而,通信设备制造商却容易忽视无源器件的可靠性,镍铬和氮化钽两种使用较多的片状电阻具有不同的性能。

On the Validity of the Imbert-Fick Law: Mathematical Modelling of Eye Pressure Measurement

Ophthalmologists rely on a device known as the Goldmann applanation tonometer to make intraocular pressure (IOP) measurements. It measures the force required to press a flat disc against the cornea to produce a flattened circular region of known area. The IOP is deduced from this force using the Imbert-Fick principle. However, there is scant analytical justification for this analysis. We present a mathematical model of tonometry to investigate the relationship between the pressure derived by tonometry and the IOP. An elementary equilibrium analysis suggests that there is no physical basis for traditional tonometric analysis. Tonometry is modelled using a hollow spherical shell of solid material enclosing an elastic liquid core, with the shell in tension and the core under pressure. The shell is pressed against a rigid flat plane. The solution is found using finite element analysis. The shell material is anisotropic. Values for its elastic constants are obtained from literature except where data are unavailable, when reasonable limits are explored. The results show that the force measured by the Goldmann tonometer depends on the elastic constant values. The relationship between the IOP and the tonometer readings is complex, showing potentially high levels of inaccuracy that depend on IOP.

国内简讯

2014年国际橡胶会议在北京隆重召开2014年9月16—18日,2014年国际橡胶会议（IRC2014）在中国北京国际会议中心隆重召开。来自27个国家和地区的特邀嘉宾和业界代表逾700人出席大会。中国石油和化学工业联合会会长、中国化工学会理事长、IRC 2014组委会主席李勇武先生致欢迎词;国际橡胶会议组织（IRCO）主席、来自澳大利亚的Anthony Hammond先生到会致辞,中国化工集团公司副总经理范小森致贺词。

2014年国际橡胶会议在京圆满召开

2014年国际橡胶会议（IRC2014）于2014年9月16—18日在中国北京圆满召开。来自中国、马来西亚、韩国、美国、日本、德国、印度等28个国家和地区的特邀嘉宾和业界代表700余人出席了本次大会。 本次会议由中国化工学会橡胶专业委员会主办,北京橡胶工业研究设计院承办,中国橡胶工业协会、中国合成橡胶工业协会、中国天然橡胶协会和风神轮胎股份有限公司协办,多家单位支持。为指导会议，以中国科学院院士王佛松、沈之荃，中国工程院院士毛炳权、曹湘洪领衔橡胶行业国际知名专家、学者组成了国际技术顾问委员会；以曹湘洪院士、毛炳权院士为主任委员，何晓玫、张立群为副主任委员，携国内知名学者、科技工作者组成了技术委员会。