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HPLC法同时测定N-芴甲氧羰基-O-叔丁基-L-苏氨酸中的6个杂质

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药物分析杂志 2024年第3期44卷 468-474页

作者：杨欣茹李铁健胡发红韩忠丽张贵民鲁南制药集团股份有限公司国家手性制药工程技术研究中心临沂273400

目的:建立高效液相色谱同时测定N-芴甲氧羰基-O-叔丁基-L-苏氨酸中6个特定杂质的方法。方法:采用YMC Triart C18(250 mm×4.6 mm,3μm)色谱柱,以0.1%三氟乙酸水溶液为流动相A,以0.1%三氟乙酸乙腈溶液为流动相B,流速1.0 mL·min^(-1),梯... 详细信息

目的:建立高效液相色谱同时测定N-芴甲氧羰基-O-叔丁基-L-苏氨酸中6个特定杂质的方法。方法:采用YMC Triart C18(250 mm×4.6 mm,3μm)色谱柱,以0.1%三氟乙酸水溶液为流动相A,以0.1%三氟乙酸乙腈溶液为流动相B,流速1.0 mL·min^(-1),梯度洗脱,检测波长265 nm,柱温30℃,进样体积10μL。结果:N-芴甲氧羰基-O-叔丁基-L-苏氨酸与相邻杂质峰的分离良好;6个杂质分离度均大于1.5;且在相应质量浓度范围内呈现良好的线性关系(r≥0.999);6个杂质检测限和定量限分别约为0.03μg·mL^(-1)和0.06μg·mL^(-1);6个杂质的平均回收率(n=9)在97.6%~98.8%范围内。3批N-芴甲氧羰基-O-叔丁基-L-苏氨酸测定结果显示,杂质1的含量<0.2%,杂质4的含量<0.1%,其他4种杂质未检出,总杂含量<1%。结论:本方法分离度好,灵敏度高,专属性强,适用于N-芴甲氧羰基-O-叔丁基-L-苏氨酸中有关物质的检测。

关键词： N-芴甲氧羰基-O-叔丁基-L-苏氨酸高效液相色谱法杂质梯度洗脱

神经示踪染料DiI影响溃疡性结肠炎小鼠背根神经节神经元电学特性

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中国疼痛医学杂志 2024年第5期30卷 331-340页

作者：雒炜刘永斌刘坤刘允高昕妍乔海法陕西中医药大学针灸推拿学院咸阳712046 中国中医科学院针灸研究所机能研究室北京100700

目的:探究在神经示踪结合膜片钳全细胞记录的实验中,示踪染料DiI是否会对小鼠背根神经节(dorsal root ganglion,DRG)神经元兴奋性产生影响。方法:采用SPF级雄性C57BL/6J小鼠,经5%葡聚糖硫酸钠(dextran sulfate sodium,DSS)诱导溃疡性结... 详细信息

目的:探究在神经示踪结合膜片钳全细胞记录的实验中,示踪染料DiI是否会对小鼠背根神经节(dorsal root ganglion,DRG)神经元兴奋性产生影响。方法:采用SPF级雄性C57BL/6J小鼠,经5%葡聚糖硫酸钠(dextran sulfate sodium,DSS)诱导溃疡性结肠炎(ulcerative colitis,UC)模型,在T12~L2皮节多点注射DiI逆向示踪躯体感觉神经元,分离全组织DRG并进行全细胞膜片钳记录。结果:HE染色结果显示模型诱导成功。膜片钳记录未经标记的小鼠DRG神经元,模型组小鼠膜电位兴奋性高于正常组小鼠。两组小鼠示踪后,正常示踪组和模型示踪组DiI+神经元兴奋性均低于本组DiI-神经元;与两未示踪组的神经元相比较,两示踪组的DiI-神经元兴奋性分别升高。结论:本实验结果明确了示踪剂DiI会降低DRG神经元的兴奋性,提示相关实验设计中应注意示踪剂的应用对神经元兴奋性的影响,以保证实验结果的可靠性。

关键词：神经示踪背根神经节兴奋性 DiI 膜片钳

面向燃料电池双极板的不锈钢表相掺杂耐蚀性高通量计算与分析

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原子与分子物理学报 2024年第3期41卷 152-162页

作者：张浩明张頔徐竹田彭林法来新民上海交通大学上海市复杂薄板结构数字化制造重点实验室上海200240 上海交通大学机械系统与振动国家重点实验室上海200240

通过基于密度泛函理论(DFT)的第一性原理高通量计算,筛选了可以提高不锈钢双极板钝化层在PEMFCs工作环境中的耐蚀性的掺杂元素.基于Cr_(2)O_(3)的(101-2)切面构建计算模型,对其进行了48种元素的掺杂替换,考虑228种掺杂构型.根据掺杂结... 详细信息

通过基于密度泛函理论(DFT)的第一性原理高通量计算,筛选了可以提高不锈钢双极板钝化层在PEMFCs工作环境中的耐蚀性的掺杂元素.基于Cr_(2)O_(3)的(101-2)切面构建计算模型,对其进行了48种元素的掺杂替换,考虑228种掺杂构型.根据掺杂结构和位移能量、掺杂元素被分为4类,并采用不同的吸附、空位计算方案.根据不同掺杂类型采用不同的吸附、空位计算方案,计算了每种掺杂元素对功函数、F的吸附能和Cr/O的空位形成能的影响.计算结果显示,C、N、In、Ru对于不锈钢钝化层的各项耐蚀性参数提升效果较好;Au、Rh、Pt、Ir、Co、Ni也能较好地提升耐蚀性,但是存在成本高或者危害质子膜的问题;Ag、Cu、Sn、Ge可以抑制空位形成和F吸附,但会造成功函数下降;Zn可以提高功函数并抑制F吸附.此外,对于电子态密度的计算表明,掺杂原子与Cr原子形成的稳定键合是耐蚀性参数提升的重要因素.

关键词：高通量计算不锈钢双极板耐蚀性第一性原理计算

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高液压射台前板球墨铸铁件铸造工艺设计

铸造 2024年第2期73卷 239-243页

作者：张鑫宋贤发李继强贾志欣项铮宇吴超李美红浙江大学浙江杭州310058 宁波拓铁机械有限公司浙江宁波315100 浙大宁波理工学院浙江宁波315100

射台前板是注塑机中的关键部件之一,其油缸孔部位加工精度高且有承压要求。本文介绍了高液压球墨铸铁射台前板铸件的工艺难点,设计了分型方案、浇注系统及冷却系统,并借助软件模拟分析了缩孔与缩松缺陷,确定了型芯方案。通过合理选择铸... 详细信息

射台前板是注塑机中的关键部件之一,其油缸孔部位加工精度高且有承压要求。本文介绍了高液压球墨铸铁射台前板铸件的工艺难点,设计了分型方案、浇注系统及冷却系统,并借助软件模拟分析了缩孔与缩松缺陷,确定了型芯方案。通过合理选择铸件的化学成分,严格控制球化、孕育及浇注过程,铸件本体渗透检验(PT)达到EN1371标准的质量等级I级,附铸试块铸件的力学性能和金相组织均符合客户标准。

关键词： QT450-10A 铸造工艺激冷系统砂芯结构

Finite element modeling of macrosegregation coupled with shrinkage cavity in steel ingots using arbitrary Lagrangian-Eulerian model

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China Foundry 2019年第5期16卷 291-299页

作者： Kang-xin Chen Hao Shi Hou-fa Shen Key Laboratory for Advanced Materials Processing Technology Ministry of EducationSchool of Materials Science and Engineering Tsinghua University

Shrinkage cavity has significant influence on macrosegregation in steel ingots. An arbitrary Lagrangian-Eulerian (ALE) model based on volume averaging method is developed to predict the coupled formation progress of macrosegregation and shrinkage cavity during solidification of steel ingots. The combined effect of thermal-solutal convection and solidification shrinkage on macrosegregation is considered in the model. A specially designed mesh update algorithm is proposed to consider the formation of shrinkage cavity. The streamline-upwind/Petrov–Galerkin (SUPG) stabilized finite element algorithm is adopted to solve the conservation equations. Two solution methods for the energy conservation equation are proposed, i.e. the temperature-based solver and enthalpy-based solver. A Pb-48wt.%Sn solidification benchmark is used for validation. Then, the ALE model is applied to a Fe-3.6wt.%C industrial steel ingot. The formation progress of macrosegregation coupled with shrinkage cavity is predicted. By comparison with the predictions of the finite element model and finite volume model, the effect of shrinkage cavity formation on macrosegregation is investigated. Results show that the formation of shrinkage cavity can significantly change the segregation region and segregation degree at the hot top. It is demonstrated that the ALE model can predict the coupled formation of macrosegregation and shrinkage cavity in steel ingots.

关键词： steel ingot macrosegregation shrinkage cavity ALE model finite element modeling

Highly selective CO methanation over amorphous Ni-Ru-B/ZrO_2 catalyst

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Chinese Chemical Letters 2009年第8期20卷 889-892页

作者： Qi Hai Liu xin fa Dong Wei Ming Lin School of Chemistry and Chemical Engineering South China University of Technology Guangzhou 510640 China

Amorphous Ni-Ru-B/ZrO2 catalyst was prepared by the means of chemical reduction, and selective CO methanation as a strategy for CO removal in fuel processing applications was investigated over the amorphous Ni-Ru-B/ZrO2 catalyst. The result showed that, at the temperature of 210-230 ℃, the catalyst was shown to be capable of reducing CO in a hydrogen-rich reformate to less than 10 ppm, while keeping the CO2 conversion below 1.55% and the hydrogen consumption below 6.50%. ？2009 xin fa Dong. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

关键词： Selective methanation CO Amorphous Ni-Ru-B/ZrO2 catalyst

Profound loss of microbial necromass carbon in permafrost thaw-subsidence in the central Tibetan Plateau

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Advances in Climate Change Research 2024年第4期15卷 647-657页

作者： Wen-Ting ZHOU Quan-Lian LI Shi-Chang KANG Xiao-Dong WU Tian MA Xiao-Bo WU xin XIONG Tanuj SHUKLA Maheswar RUPAKHETI Dipesh RUPAKHETI Da-He QIN Xiu-Feng YIN Cryosphere Research Station on the Qinghai-Tibet Plateau State Key Laboratory of Cryospheric ScienceNorthwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Key Laboratory of Cryospheric Science and Frozen Soil Engineering Norhwest Instiute of Eco-Evironment and ResourcesChinese Academy of Scienes Lanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems and College of Pastoral Agriculture Science and TechnologyLanzhou UniversityLanzhou730020China Lushan Botanical Garden Chinese Academy of SciencesJiujiang 332900China Research Institute for Sustainability-Helmholtz Centre Potsdam Potsdam 14467Germany Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Collaborative Innovation Center of Atmospheric Environment and Equipment TechnologySchool of Environmental Science and EngineeringNanjing University of Information Science and TechnologyNanjing 210044China

Climate warming is causing rapid permafrost degradation,including thaw-induced subsidence,potentially resulting in heightened carbon ***,our understanding of the levels and variations of carbon components in permafrost,particularly during the degradation process,remains *** uncertainties arising from this process lead to inaccurate assessments of the climate effects during permafrost *** vast expanses of permafrost in the Tibetan Plateau,there is limited research available on SOC components,particularly in the central Tibetan *** remarkable variations in hydrothermal conditions across different areas of the Tibetan Plateau,the existing limited studies make it challenging to assess the overall SOC components in the permafrost across the Tibetan Plateau and simulate their future *** this study,we examined the properties of soil organic carbon(SOC)and microbial necromass carbon(MicrobialNC)in a representative permafrost thaw-subsidence area at the southern edge of continuous permafrost in the central Tibetan *** results indicate that prior to the thaw-subsidence,the permafrost had a SOC content of 72.68±18.53 mg g^(-1),with MicrobialNC accounting for 49.6%.The thaw-subsidence of permafrost led to a 56.4%reduction in SOC,with MicrobialNC accounting for 70.0%of the lost *** constitutes the primary component of permafrost SOC,and it is the main component that is lost during thaw-subsidence *** in MicrobialNC are primarily correlated with factors pH,plant input,and microbial *** present study holds crucial implications for both the ecological and biogeochemical processes associated with carbon release from permafrost,and it furnishes essential data necessary for modeling the global response of permafrost to climate *** on this study and previous research,permafrost thawing in the Tibetan Plateau causes substantial loss of ***,there's remarkable heterogeneit

关键词： Tibetan Plateau Thaw-subsidence Soil organic carbon Microbial necromass carbon Amino sugars

Catalytic Oscillatory Oxidation of CO on Pt(110): on-off Control to Chaos

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Chinese Physics Letters 1998年第9期15卷 695-696页

作者： YANG Ling-fa HOU Zhong-huai xin Hou-wen Department of Chemical Physics University of Science and Technology of ChinaHefei 230026

An improved mean-field model,which specially takes into account pair correlation,was proposed to describe catalytic oscillatory oxidation of CO on Pt(110).By applying on-off control strategies under different frequency,the chemical oscillator shows an abundance of periodic doubling processes,even chaos response,and the route to the chaos and out of the chaos were both identified as period-doubling through analysis of its Lyapunov exponent *** response results reveal that structure delay effect plays an important role to the complexity of this system.

关键词： spectrum. chaos doubling

Microstructures and Mechanical Properties of Helical Bevel Gears Made by Mn-Cu Alloyed Austempered ductile Iron

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Journal of Iron and Steel Research International 2012年第2期19卷 36-42页

作者： LIU Sheng-fa CHEN Yang CHEN xin MIAO Hua-ming School of Materials Science and Engineering Wuhan University of Technology Wuhan 430070 Hubei China

Austempered ductile iron （ADI） has several advantages of replacing cast steel and forged steel in many engineering fields. A new Mn-Cu alloyed ADI with excellent mechanical properties has been developed in order to cut the cost and enlarge the application of ADI. The helical bevel gears were made of the new-developed Mn-Cu alloyed ADI. The microstructure and mechanical properties of the standard sample were investigated by optical microscope （OM）, scanning electron microscope （SEM） and performance measurement. The results showed that after a series of treatments, the mechanical properties （Rm 1007. 4 to 1200 MPa, A 5.2% to 8. 8%, HRC 32 to HRC 35, O^K 70 to 120 J/cmz ） of the Mn-Cu alloyed ADI standard sample could reach European standard EN1564-97/ EN-CJS-1000-5. The surface hardness after helical bevel gears meshing was significantly increased due to the formation of martensite. The bench test and traffic running testing results suggested that the new Mn-Cu alloyed ADI with ultimate life and median life respectively exceeding 30×104 and 50 × 10^4 times could replace 20CrMnTi forged steel for manufacturing the EQ140 helical bevel gears.

关键词： ADI Mn mechanical property helical bevel gear