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Adhesion strength of tetrahydrofuran hydrates is dictated by substrate stiffness

Petroleum Science 2024年第1期21卷 667-673页

作者： Yan-Wen Lin Tong Li Yi Zhang Wei-Wei Yan xiao-ming chen Zhi-Sen Zhang Jian-Yang Wu Department of Physics Research Institute for Biomimetics and Soft MatterJiujiang Research Institute and Fujian Provincial Key Laboratory for Soft Functional Materials ResearchXiamen UniversityXiamen361005FujianChina Key Laboratory of Marine Materials and Related Technologies Zhejiang Key Laboratory of Marine Materials and Protective TechnologiesNingbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo315201ZhejiangChina Key Laboratory of Icing and Anti/De-icing China Aerodynamics Research and Development CenterMianyang621000SichuanChina Micro-and Nano-technology Research Center State Key Laboratory for Manufacturing Systems EngineeringXi’an Jiaotong UniversityXi’an710049ShaanxiChina Electronic Materials Research Lab Key Laboratory of the Ministry of EducationXi’an Jiaotong UniversityXi’an710049ShaanxiChina NTNU Nanomechanical Lab Norwegian University of Science and Technology(NTNU)Trondheim7491Norway

Understanding the hydrate adhesion is important to tackling hydrate accretion in ***,the relationship between the Tetrahydrofuran(THF)hydrate adhesion strength(AS)and surface stiffness on elastic coatings is systemically examined by experimental shear force measurements and theoretical *** mechanical factor-elastic modulus of the coatings greatly dictates the hydrate AS,which is explained by the adhesion mechanics theory,beyond the usual factors such as wettability and structural ***,the hydrate AS increases with reducing the thickness of the elastic coatings,resulted from the decrease of the apparent surface elastic *** effect of critical thickness for the elastic materials with variable elastic modulus on the hydrate AS is also *** study provides deep perspectives on the regulation of the hydrate AS by the elastic modulus of elastic materials,which is of significance to design anti-hydrate surfaces for mitigation of hydrate accretion in petro-pipelines.

关键词： Hydrate Adhesion strength Elastic modulus Coatings

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一例整合了三联吡啶钌和卟啉锌的金属-有机框架材料用于光催化二氧化碳还原全反应

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物理化学学报 2024年第4期40卷 4-10页

作者：陈慧滢朱浩林廖培钦陈小明中山大学化学学院生物无机与合成化学教育部重点实验室广州510275

利用源源不断的太阳能,将CO_(2)和水转化为增值化学品,是缓解温室效应与能源危机的一种有前途的方法。由于催化体系中的不同功能性部分难以实现氧化与还原反应的耦合,使用水作为还原剂实现光催化CO_(2)还原是一项具有挑战性的工作。金... 详细信息

利用源源不断的太阳能,将CO_(2)和水转化为增值化学品,是缓解温室效应与能源危机的一种有前途的方法。由于催化体系中的不同功能性部分难以实现氧化与还原反应的耦合,使用水作为还原剂实现光催化CO_(2)还原是一项具有挑战性的工作。金属有机框架(metal-organic framework,MOF)由于其较大的比表面积、多样化的活性位点和结构可调性,是CO_(2)光催化还原全反应的良好备选材料。本文中,我们首先整合了具有光活性的锌(Ⅱ)卟啉基元与联吡啶钌(Ⅱ)基元,构建了一种MOF光催化剂,记作PCN-224(Zn)-Bpy(Ru)。为了进行比较,还合成了两种仅具有锌(Ⅱ)卟啉或联吡啶钌(Ⅱ)基元的同构MOF,分别记作PCN-224(Zn)-Bpy和PCN-224-Bpy(Ru)。由测试结果可知,PCN-224(Zn)-Bpy(Ru)在乙腈和水混合溶液中表现出对CO_(2)还原可观的光催化活性(CO产率为7.6μmol·g^(-1)·h^(-1)),无需额外添加助催化剂、光敏剂或牺牲剂。通过质谱仪观测到^(13)CO(m/z=29)、^(13)C^(18)O(m/z=31)、^(16)O^(18)O(m/z=34)和^(18)O_(2)(m/z=36)信号,表明CO_(2)和H_(2)O分别作为CO和O_(2)的碳源和氧源,这进一步证实了光催化CO_(2)还原与H_(2)O氧化的耦合。然而,在相同条件下对PCN-224-Bpy(Ru)与PCN-224(Zn)-Bpy的光催化性能进行测试,CO产率分别仅为1.5与0μmol·g^(-1)·h^(-1)。机理研究表明,PCN-224(Zn)-Bpy(Ru)的最低未占据分子轨道(LUMO)电位比CO_(2)/CO的氧化还原电位更负,而最高占据分子轨道(HOMO)电位比H_(2)O/O_(2)的氧化还原电位更正,在热力学上满足了光催化CO_(2)还原全反应的要求。相比之下,不含联吡啶钌(Ⅱ)基元的PCN-224(Zn)-Bpy的HOMO电位更负于H_(2)O/O_(2)的氧化还原电位,这表明联吡啶钌(Ⅱ)基元在热力学上是光催化CO_(2)还原全反应所必需的。此外,光致发光光谱中,荧光几乎被PCN-224(Zn)-Bpy(Ru)猝灭,且平均光致发光寿命比PCN-224(Zn)-Bpy和PCN-224-Bpy(Ru)更长,这表明PCN-224中光生载流子的复合率较低。与PCN-224(Zn)-Bpy和PCN-224-Bpy(Ru)相比,PCN-224的光电流更高,这一现象也支持了中后者光生载流子的复合率较低这一结论。总而言之,在光催化CO_(2)还原过程中,锌卟啉(Ⅱ)配体既作为光敏单元,又作为CO_(2)还原活性位点,而联吡啶钌(Ⅱ)基元与锌(Ⅱ)卟啉基元的结合可以优化光催化剂的能带结构,进而促进光催化CO_(2)还原与H_(2)O氧化的耦合,从而实现了高效光催化CO_(2)还原全反应。

关键词：金属有机框架锌(Ⅱ)卟啉衍生物联吡啶(Ⅱ)钌配合物光生电荷光催化CO_(2)还原

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Multiple-antenna techniques in nonorthogonal multiple access:a review

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Frontiers of Information Technology & Electronic Engineering 2019年第12期20卷 1665-1697页

作者： Fei-yan TIAN xiao-ming chen chen College of Information Science and Electronic Engineering Zhejiang UniversityHangzhou 310027China

As a promising physical layer technique, nonorthogonal multiple access(NOMA) can admit multiple users over the same space-time resource block, and thus improve the spectral efficiency and increase the number of access users. Specifically, NOMA provides a feasible solution to massive Internet of Things(IoT) in 5G and beyond-5G wireless networks over a limited radio spectrum. However, severe co-channel interference and high implementation complexity hinder its application in practical systems. To solve these problems, multiple-antenna techniques have been widely used in NOMA systems by exploiting the benefits of spatial degrees of freedom. This study provides a comprehensive review of various multiple-antenna techniques in NOMA systems, with an emphasis on spatial interference cancellation and complexity reduction. In particular, we provide a detailed investigation on multiple-antenna techniques in two-user, multiuser, massive connectivity, and heterogeneous NOMA ***, future research directions and challenges are identified.

关键词： Nonorthogonal multiple access Multiple-antenna technique B5G Internet of Things

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Experimental evaluation of the effect of an internal heat exchanger on a transcritical CO_2 ejector system

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第2期12卷 146-153页

作者： xiao-xiao XU Guang-ming chen Li-ming TANG Zhi-jiang ZHU Shuang LIU Institute of Refrigeration and Cryogenics State Key Laboratory of Clean Energy Utilization Zhejiang University Hangzhou 310027 China

This study presents experimental results focused on a performance comparison of a transcritical CO2 ejector system without an internal heat exchanger(IHX) (EJE-S) to a transcritical CO2 ejector system with an IHX(EJE-IHX-S) . The comparison includes the effects of changes in operating conditions such as cooling water flow rate and inlet temperature. Experiments are conducted to assess the influence of the IHX on the heating coefficient of performance(COPr) ,heating capacity,entrainment ratio,pressure lift,and other parameters. The primary flow rate of the EJE-IHX-S is higher than that of the EJE-S. The pressure lift and actual ejector work recovery are reduced when the IHX is added to the transcritical CO2 ejector system. Using a more practical performance calculation,the compression ratio in the EJE-S is reduced by 10.0%-12.1%,while that of EJE-IHX-S is reduced only by 5.6%-6.7% compared to that of a conventional transcritical CO2 system. Experimental results are used to validate the findings that the IHX weakens the contribution of the ejector to the system performance.

关键词： CO2 ejector system Transcritical cycle Heating coefficient of performance (COPr)

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构筑未来:框架化学的研究前沿与产业化展望

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中国科学：化学 2024年第6期54卷 815-821页

作者：岳衎丁三元雷浩卜显和陈小明付雪峰国家自然科学基金委员会化学科学部北京100085 华南理工大学前沿软物质学院广州510640 兰州大学功能有机分子化学国家重点实验室化学化工学院兰州730000 暨南大学广东省功能配位超分子材料及应用重点实验室化学与材料学院广州510632 南开大学材料科学与工程学院天津300350 中山大学化学学院广州510275

基于“框架化学的基础及应用研究”研讨会,本文阐述了“框架化学”的科学内涵,从框架结构的设计合成、精确表征、高性能化和产业应用四个方面综述了框架化学领域的主要研究进展,凝练了该领域的关键科学问题,并提出了面向国家需求和产业... 详细信息

基于“框架化学的基础及应用研究”研讨会,本文阐述了“框架化学”的科学内涵,从框架结构的设计合成、精确表征、高性能化和产业应用四个方面综述了框架化学领域的主要研究进展,凝练了该领域的关键科学问题,并提出了面向国家需求和产业发展的重点发展方向.

关键词：框架化学多孔材料金属-有机框架共价有机框架超分子有机框架

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Detecting the possibility of a type of photon number splitting attack in decoy-state quantum key distribution

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Chinese Physics B 2022年第12期31卷 67-72页

作者： xiao-ming chen Lei chen Ya-Long Yan Beijing University of Posts and Telecommunications Beijing 100876China Beijing Electronic Science and Technology Institute Beijing 100070China University of Science and Technology of China Hefei 230026China

The existing decoy-state quantum key distribution(QKD)beating photon-number-splitting(PNS)attack provides a more accurate method to estimate the secure key rate,while it still considers that only single-photon pulses can generate secure keys in any ***,multiphoton pulses can also generate secure keys if we can detect the possibility of PNS attack in the *** ultimate goal of this line of research is to confirm the absence of all types of PNS *** particular,the PNS attack mentioned and detected in this paper is only the weaker version of PNS attack which significantly changes the observed values of the legitimate *** this paper,under the null hypothesis of no weaker version of PNS attack,we first determine whether there is an attack or not by retrieving the missing information of the existing decoy-state protocols,extract a Cauchy distribution statistic,and further provide a detection method and the type I error *** the result is judged to be an attack,we can use the existing decoy-state method and the GLLP formula to estimate the secure key ***,the pulses with the same basis received including both single-photon pulses and multiphoton pulses,can be used to generate the keys and we give the secure key rate in this ***,the associated experiments we performed(i.e.,the significance level is 5%)show the correctness of our method.

关键词： quantum key distribution photon number splitting decoy state hypothesis testing

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A review of thoracic radiotherapy target volume definition for limited-stage small cell lung cancer

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中华放射医学与防护杂志 2015年第1期35卷 57-61页

作者： Hu xiao chen ming 310022 Hangzhou Department of Radiation OneologyZhejiang Cancer Hospital and Zhejiang Key Laboratory ofRadiation Oncology

Thoracic radiotherapy has been demonstrated in a number of clinical studies that can reduce the local recurrence rate and improve the long-term survival rate in limited-stage small cell lung cancer (SCLC) patients and thus is an indispensable part in the comprehensive treatment of SCLC[1-2] However,many controversies have existed for a long time in the implementation of thoracic radiotherapy (TRT),the target volumes for radiation is one of them[3].

关键词：临床医学诊断放射医学

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Crystal structures and phase transitions in two new hybrid crystals: (Me_(3)NCH_(2)CH_(2)X)_(4)[Ni(NCS)_6](X=Cl and Br)

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Chinese Chemical Letters 2023年第3期34卷 486-489页

作者： De-Xuan Liu Zhi-Hong Yu xiao-Xian chen Wei-Xiong Zhang xiao-ming chen MOE Key Laboratory of Bioinorganic and Synthetic Chemistry School of ChemistrySun Yat-sen UniversityGuangzhou 510275China

Understanding phase transitions in multi-component crystals is of importance for regulating specified functional ***,we present two new organic-inorganic hybrid crystals,(Me_(3)NCH_(2)CH_(2)X)_(4)[Ni(NCS)_6](X=Cl and Br),revealing distinct phase ***,the Clsubstituted cations weakly interact with discrete inorganic part hence reveal step-wise dynamic changes upon heating,which result in multi-step solid-solid phase transitions (P1-P2_1/n-A2/a-Cmce) including a ferroelastic one with a spontaneous strain of *** the Br-substituted cations with larger steric effect prevent the solid-solid phase transition but give a solid-liquid phase transition at above 419 *** present instances well demonstrate the complicity for multi-component crystals arising from the delicate balance established by abundant weak intermolecular interactions,and inspire the design of novel phase-transition materials by judiciously assembling multi-component crystals.

关键词： Hybrid crystal Phase transition Ferroelasticity Intermolecular interaction Hirshfeld surface analysis

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Using PVP/SDS Complex as a Probe to Study the Inclusion Complex of β-cyclodextrin with SDS in Aqueous Solution

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Chinese Journal of Chemical Physics 2009年第5期22卷 541-544,I0002页

作者： xiao-ming chen Hai-yang Yang Ping-sheng He Department of Polymer Science and Engineering University of Science and Technology of China Hefei 230025 China

PVP/SDS complex was applied as a probe to study the interaction between β-cyclodextrin （β-CD） and sodium dodecyl sulfate （SDS） in aqueous solution. It has been found that a critical concentration, namely cs, exists in the relative viscosity of solution containing PVP/SDS complex versus β-CD concentration plot. As the β-CD concentration is less than cs, the relative viscosity of solution decreases sharply by adding β-CD into solution successively. On the other hand, as the β-CD concentration is greater than cs, the relative viscosity of solution increases gradually by adding β-CD into solution. The decrease of the relative viscosity of solution containing PVP/SDS in the presence of β-CD is just due to the inclusion complex of β-CD with the guest molecule SDS. And, this inclusion interaction takes down SDS from the PVP chains in solution. The ratio of the host molecule β-CD to the guest molecule SDS can be calculated from Cs. In our experiment the inclusion ratio of β-CD to SDS is 1/1. The further experimental results indicate that cs is associated with SDS but free from PVP in PVP/SDS complex. However, the inclusion ratio of β-CD to SDS has proved to be independent of either SDS or PVP in PVP/SDS complex.

关键词： PVP/SDS complex β-cyclodextrin Relative viscosity Inclusion ratio

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Dynamic Pendulum Effect of an Exceptionally Flexible Pillared-Layer Metal-Organic Framework

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Chinese Journal of Chemistry 2021年第10期39卷 2718-2724页

作者： Hao-Long Zhou Jie Bai xiao-Yun Tian Zong-Wen Mo xiao-ming chen MOE Key Laboratory of Bioinorganic and Synthetic Chemistry School of ChemistrySun Yat-Sen UniversityGuangzhouGuangdong510275 China Department of Chemistry ond Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province Shantou UniversityShantouGuangdong 515063China

Main observation and conclusion Magnifying the controllable directional motions of molecular machines to the macroscopic levels is a significant topic for *** metal–organic frameworks with long-range order and responsive structural transformation under external stimuli may be an appropriate platform for achieving the *** taking advantage of the single-crystal to single-crystal manner of soft porous crystals,we utilize single-crystal X-ray diffraction to directly observe the dynamic structural inversion of a new three-fold interpenetrated pillared-layer metal-organic framework[Co(edba)(bpy)](MCF-83,H2edba=4,4’-(ethyne-1,2-diyl)dibenzoic acid,bpy=4,4’-bipyridine).More interestingly,the dynamic inversions of the pillars and layers are selectively guest-controllable and independent,allowing precise control of the directional shape changes,which is the key of constructing intelligent materials to accomplish a complex *** mechanism is further studied by combining the X-ray diffraction analyses,sorption measurements and molecular simulations.

关键词： Porous coordination polymers Metal-organic frameworks Structural transformation X-ray diffraction Adsorption

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