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Acta Metallurgica Sinica(English Letters) 2021年第9期34卷 1223-1233页

作者： Jian-Bin Zhan yan-jin lu jin-Xin Lin College of Chemistry and Materials Science Fujian Normal UniversityFuzhou 350007China Key Laboratory of Optoelectronic Materials Chemistry and Physics Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China

In this study, the infl uence of laser remelting on the relative density, martensitic transformation temperatures(MTTs), and mechanical properties of a NiTi alloy fabricated by selective laser melting(SLM) at a laser power between 15 and 75 W were investigated. A relative alloy density of approximately 99% was achieved in the power range of 45–60 W corresponding to the forming energy density range of 65.45–87.27 J/mm3. The MTTs increased with the increase in the energy density;thus, the initial contents of the B2 and B19′ phases of the SLM-produced NiTi alloy can be tailored by the utilized technique. However, the number of defects such as metallurgical pores and microcracks considerably increased at higher energy densities(> 87.27 J/mm3). Interestingly, the concentration of these defects was reduced by remelting in the energy density range of 21.82–65.45 J/mm3, while the alloy relative density increased to 99.7% ± 0.1% at a remelting energy density of 65.45 J/mm3. The results of tensile testing revealed that when the remelting energy was 75% or 100% of the forming energy input, the ultimate tensile strength and elongation of the alloy significantly increased. Therefore, the remelting strategy represents a promising route for manufacturing NiTi alloys with desired MTT ranges and mechanical properties.

关键词： Selective laser melting NiTi alloy Laser remelting Martensitic transformation temperature

Multiplicative Mappings of Rings

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Acta Mathematica Sinica,English Series 2006年第4期22卷 1017-1020页

作者： Fang yan lu jin Hai XIE Department of Mathematics Suzhou University Suzhou 215006 P. R. China

Let R and F be arbitrary associative rings. A mapping φ of R onto F is called a multiplicative isomorphism if φ is bijective and satisfies φ（xy） = φ（x）φ（y） for all x, y ∈ R. In this short note, we establish a condition on R, in the case where R may not contain any non-zero idempotents, that assures that φ is additive, which generalizes the famous Martindale＇s result. As an application, we show that under a mild assumption every multiplicative isomorphism from the radical of a nest algebra onto an arbitrary ring is additive.

关键词： Multiplicative isomorphisms Additivity Idempotents

Higher-order dynamic effects of uncertainty risk under thick-tailed stochastic volatility

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Financial Innovation 2022年第1期8卷 1716-1737页

作者： Xiao-Li Gong jin-yan lu Xiong Xiong Wei Zhang School of Economics Qingdao UniversityQingdao 266061China College of Management and Economics Tianjin UniversityTianjin 300072China China Center for Social Computing and Analytics Tianjin 300072China

Sudden and uncertain events often cause cross-contagion of risk among various sectors of the *** paper introduces the stochastic volatility shock that follows a thick-tailed Student’s t-distribution into a high-order approximate dynamic stochastic general equilibrium(DSGE)model with Epstein–Zin preference to better analyze the dynamic effect of uncertainty risk on ***,the high-dimensional DSGE model(DSGE-SV-t)is developed to examine the impact of uncertainty risk on the transmission mechanism among macroeconomic *** empirical research found that uncertainty risk generates heterogeneous impacts on macroeconomic dynamics under different inflation levels and economic *** them,a technological shock has the strongest impact on employment and consumption *** crowding-out effect of a fiscal policy stimulus on consumption and private investments is relatively weakened when considering uncertainty risk but is more pronounced during periods of high *** risk can partly explain the decline in investments and the increase in interest rates and employment rates,given the impact of an agent’s risk *** with external economic conditions,the inflation factor has a stronger impact on the macro transmission mechanism caused by uncertainty risk.

关键词： Uncertainty risk High-dimensional DSGE Epstein-Zin preferences Stochastic volatility Thick tail distribution

Twist monomials of binary delta-matroids

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Acta Mathematica Sinica,English Series 2025年

作者： Qi yan Xian'an jin School of Mathematics and Statistics Lanzhou University School of Mathematical Sciences Xiamen University

Recently, we introduced the twist polynomials of delta-matroids and gave a characterization of even normal binary delta-matroids whose twist polynomials have only one term and posed a problem:what would happen for odd binary delta-matroids? In this paper, we show that a normal binary deltamatroid whose twist polynomials have only one term if and only if each connected component of the intersection graph of the delta-matroid is either a complete graph of odd order or a single vertex with a loop.

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页岩气开发:岩石力学的机遇与挑战

中国科学：物理学、力学、天文学 2017年第11期47卷 2-14页

作者：陈勉金衍卢运虎油气资源与工程国家重点实验室北京102249 中国石油大学(北京)石油工程学院北京102249

长水平段水平井和分段水力压裂技术是提高我国页岩气单井产量的关键技术.随着页岩气勘探开发面向深层,水平井钻完井面临安全钻进风险高、高效压裂难度大和单井产量低且递减快等难题,问题的核心仍是发展页岩储层断裂、破坏和流动模型,其... 详细信息

长水平段水平井和分段水力压裂技术是提高我国页岩气单井产量的关键技术.随着页岩气勘探开发面向深层,水平井钻完井面临安全钻进风险高、高效压裂难度大和单井产量低且递减快等难题,问题的核心仍是发展页岩储层断裂、破坏和流动模型,其本质仍为页岩气储层岩石力学问题.受机理研究制约,目前在页岩储层实验测试、裂缝系统与渗流、多场耦合和孔隙弹性等方面仍需要进一步研究与突破.中国的页岩气开发虽然取得了阶段性的成果,其面临的问题仍不容忽视,发展岩石力学相关理论对页岩气开发关键技术有重要的指导意义.同时,低油价条件下清洁开发、降低工程成本和提高单井产量是贯穿页岩气全生产周期的关键问题.本文重点分析页岩气储层力学特征评价、断裂与渗流和流固耦合等机理问题及其研究进展,介绍页岩储层实验测试、井筒安全和高效开采等关键问题,讨论未来的研究方向和热点.

关键词：页岩气岩石力学井壁稳定储层改造

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考虑毛细管力的页岩储层压裂缝网扩展研究

中国科学：物理学、力学、天文学 2017年第11期47卷 62-73页

作者：王迪陈勉金衍卢运虎中国石油大学(北京)油气资源与工程国家重点实验室北京102249 中国石油大学(北京)石油工程学院北京102249

页岩储层中广泛发育着各种尺度的天然裂缝,这些天然裂缝小到纳米、微米量级,大到毫米甚至是工程量级,显著影响着压裂后的裂缝网络形态.同时,在页岩压裂施工过程中,压裂液会进入到这些不同尺度的天然裂缝中,在天然裂缝内部存在气-液两相... 详细信息

页岩储层中广泛发育着各种尺度的天然裂缝,这些天然裂缝小到纳米、微米量级,大到毫米甚至是工程量级,显著影响着压裂后的裂缝网络形态.同时,在页岩压裂施工过程中,压裂液会进入到这些不同尺度的天然裂缝中,在天然裂缝内部存在气-液两相流体,产生毛细管力.当天然裂缝尺度不同时,在裂缝中产生的毛细管力大小不同,尤其是当天然裂缝尺度较小时,在其内部会产生较大的毛细管力,进而显著影响天然裂缝内压裂液的流动以及压裂裂缝网络的扩展.本文建立了同时考虑天然裂缝尺度以及压裂液与储层岩石润湿特性的页岩压裂缝网扩展模型,研究了在毛细管力影响下的压裂裂缝网络的扩展特征.通过研究发现,当天然裂缝初始长度较长、缝宽较小、压力液与储层润湿性较强时,天然裂缝更容易扩展,形成较大规模的裂缝网络.当天然裂缝尺度各异时,将形成复杂的裂缝网络,该模拟结果与室内大型页岩水力压裂实验中观察到的裂缝网络扩展形态相同.

关键词：页岩气压裂缝网扩展天然裂缝尺度压裂液润湿性毛细管力

Trinuclear gold-catalyzed site-selective alkylation of peptides

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Science China Chemistry 2025年第1期68卷 249-256页

作者： Qing-Yun Fang Chengyihan Gu Yinghan Chen Wencheng yan Yong Liang Weipeng Li Chengjian Zhu Jie Han jin Xie State Key Laboratory of Coordination Chemistry Jiangsu Key Laboratory of Advanced Organic Materials Chemistry and Biomedicine Innovation Center (Chem BIC) School of Chemistry and Chemical Engineering Nanjing University Green Catalysis Center College of Chemistry Zhengzhou University State Key Laboratory of Natural Medicines China Pharmaceutical University

Selective modification of peptides has always been a challenging issue. The selective alkylation of peptides can alter the biological activity and physical properties of molecules, and it has gained significant research interest. We herein disclose an intriguing gold-catalyzed alkylation of peptides using bench-stable unactivated alkyl bromides under photoredox catalysis. A wide range of structurally diverse primary, secondary and tertiary alkyl bromides serve as effective coupling partners to precisely connect with the α-C(sp3)–H in glycine residue of peptides. This protocol demonstrates an exceptionally broad scope for alkyl halides and excellent tolerance for a wide range of useful functional groups. A series of relay transformations to construct cyclic peptides, to proceed click reaction and to realize peptide fluorescence labeling further enhance its synthetic practicality. In addition, mechanistic studies and density functional theory(DFT) calculations reveal an inner-sphere and subsequent outersphere single electron transfer(SET) mechanism.

关键词： gold catalysis peptide alkylation C-C coupling radical

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Bending Stiffness of Concrete-Filled Steel Tube and Its Influence on Concrete Placement Timing of Composite Beam-String Structure

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Structural Durability & Health Monitoring 2025年第1期19卷 55-75页

作者： Zhenyu Zhang Quan jin Haitao Zhang Zhao Liu Yuyang Wu Longfei Zhang Renzhang yan CCCC Third Highway Engineering Co. Ltd.Beijing101300China School of Civil Engineering Chongqing Jiaotong UniversityChongqing400074China

When the upper chord beam of the beam-string structure(BSS)is made of concrete-filled steel tube(CFST),its overall stiffness will change greatly with the construction of concrete placement,which will have an impact on the design of the tensioning plans and selection of control measures for the *** order to accurately obtain the bending stiffness of CFST beam and clarify its impact on the mechanical properties of composite BSS during construction,the influence of some factors such as height-width ratio,wall thickness of steel tube,elasticity modulus of concrete,and friction coefficient on the bending stiffness are analyzed parametrically by the numerical simulation technology based on an actual *** calculation formula of the equivalent bending stiffness of CFST is also established through mathematical statistical ***,the equivalent bending stiffness is introduced into the construction and use stages of the composite BSS,respectively,and the mechanical properties such as prestress-tensioning control value,structural deformation,and internal force of key members are comparatively analyzed when adopting two different construction ***,the optimal construction plan of concrete placement first and then prestress-tensioning is proposed.

关键词： Concrete panels freeze-thaw damage compression-shear crack tension-shear crack

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浅谈杨树容器育苗技术

内蒙古林业调查设计 2010年第4期33卷 49-50页

作者：严进录青海省林业工程咨询中心西宁810003

文章从苗圃选择、苗床整地、基质配制、种子播种、苗期管理、成品苗出圃等环节介绍了一年生容器苗的育苗技术。

关键词：杨树容器育苗技术

二化螟谷胱甘肽-S-转移酶基因的鉴定与表达模式分析

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应用昆虫学报 2018年第3期55卷 349-359页

作者：金燕璐张邦贤林华峰安徽农业大学植物保护学院合肥230036 滁州学院科技处滁州239000

【目的】鉴定二化螟Chilo suppressalis谷胱甘肽-S-转移酶(Glutathione-S-transferase,GST)基因,明确GST基因在幼虫各组织中的表达谱,并分析GST应对氯虫苯甲酰胺胁迫的表达模式。【方法】从二化螟转录组数据库中鉴定GST的c DNA序列,使... 详细信息

【目的】鉴定二化螟Chilo suppressalis谷胱甘肽-S-转移酶(Glutathione-S-transferase,GST)基因,明确GST基因在幼虫各组织中的表达谱,并分析GST应对氯虫苯甲酰胺胁迫的表达模式。【方法】从二化螟转录组数据库中鉴定GST的c DNA序列,使用实时荧光定量PCR技术分析GST在幼虫不同组织内的相对表达水平,并考察亚致死剂量氯虫苯甲酰胺处理幼虫之后GST表达水平的变化。【结果】从二化螟转录组中检索得到16个GST基因,分别被命名为Cs GSTd1-Cs GSTu1。这16个GST被划分为6个家族(Delta、Epsilon、Omega、Sigma、Zeta和Theta)和一个"未分类"亚组(Unclassified subgroup)。Cs GSTd2、Cs GSTd3、Cs GSTe1、Cs GSTo3、Cs GSTt1主要表达于脂肪体,Cs GSTe3主要表达于马氏管。未检测到特异表达于中肠的GST基因。氯虫苯甲酰胺处理6 h后,Cs GSTo2显著上调,但Cs GSTd2、Cs GSTd3、Cs GSTe3、Cs GSTo1和Cs GSTt1显著下调。药剂处理12 h后,Cs GSTd1、Cs GSTd2、Cs GSTd3、Cs GSTe1、Cs GSTe2、Cs GSTe3、Cs GSTo2、Cs GSTo3、Cs GSTo4和Cs GSTt1显著上调,而Cs GSTu1显著下调。【结论】Cs GSTd1、Cs GSTd2、Cs GSTd3、Cs GSTe1、Cs GSTe2、Cs GSTe3、Cs GSTo2、Cs GSTo3、Cs GSTo4和Cs GSTt1可能参与了对氯虫苯甲酰胺的解毒代谢。

关键词：二化螟谷胱甘肽-S-转移酶序列分析表达模式