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UHPLC-MS/MS法测定耕地周围地表水中5种除草剂含量

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化学研究与应用 2024年第1期36卷 191-196页

作者：王丹君易建希颜茜煜长沙环境保护职业技术学院湖南长沙410009 湖南省兽药饲料监察所湖南长沙410006 湖南省益阳生态环境监测中心湖南益阳413000

实验研究建立了超高压液相色谱-三重四级杆串联质谱法测定耕地周围地表水中2,4-二氯苯氧乙酸、灭草松、草铵膦、α-萘乙酸、马来酰肼除草剂含量的分析方法。随机采集耕地周围地表水样品,预处理后,取上述水样500 mL,调节酸度为中性,取HL... 详细信息

实验研究建立了超高压液相色谱-三重四级杆串联质谱法测定耕地周围地表水中2,4-二氯苯氧乙酸、灭草松、草铵膦、α-萘乙酸、马来酰肼除草剂含量的分析方法。随机采集耕地周围地表水样品,预处理后,取上述水样500 mL,调节酸度为中性,取HLB固相萃取柱,活化完毕后,设定程序,将上述水样以12 mL·min^(-1)的流量过柱,最后用16 mL甲醇洗脱,收集洗脱液;洗脱液于氮吹至近干,加甲醇1 mL定容,涡旋混匀,质谱分析采用多反应监测模式,定性、定量检测。2,4-二氯苯氧乙酸、灭草松、草铵膦、α-萘乙酸、马来酰肼质量浓度在0.004~4.0μg·mL^(-1)范围内呈良好的线性关系,检测限分别为0.21μg·L^(-1)、0.23μg·L^(-1)、0.14μg·L^(-1)、0.25μg·L^(-1)、0.15μg·L^(-1);三水平回收率范围在85.4%~96.6%;2,4-二氯苯氧乙酸、灭草松、草铵膦、α-萘乙酸、马来酰肼重复性RSD分别为3.4%,4.0%,3.2%,2.9%,3.6%,方法重复性良好。实验结果表明,此方法具有快速、准确等特点,方法可以用于耕地周围地表水中2,4-二氯苯氧乙酸、灭草松、草铵膦、α-萘乙酸、马来酰肼等除草剂的监测。

关键词：超高压液相色谱三重四级杆串联质谱耕地周边地表水 2 4-二氯苯氧乙酸除草剂

Realizing the excellent oxi.ation resistance of an environmental barrier coating through aluminum surface modification

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Journal of Advanced Ceramics 2024年第7期13卷 976-986页

作者： Lin Dong Wen-Qi Yang Lin Chen Guan-jun Yang Chang-Jiu Li State Key Laboratory for Mechanical Behavior of Materials School of Materials Science and EngineeringXi’an Jiaotong UniversityXi’an 710049China xi.an Aerospace Engine Company Limited in China Aerospace Science and Technology Corporation Xi’an 710065China

The lifetime of Si-based environmental barrier coatings(EBCs)is constrained by thermally grown SiO_(2)oxi.elayer(SiO_(2)-TGO),which can cause premature cracking and *** address this issue,a new approach for surfacemodification using aluminum is *** oxi.ation performance was examined in a 50 vol%H_(2)O-50 vol%O_(2)environment at 1350℃for up to 300 *** results indicate that a dense ytterbium aluminum garnet(YbAG)layer wasformed after modification,decreasing the porosity by 80%.Due to the elimination of fast diffusion channels and the lowoxygen permeability of YbAG,aluminum modification significantly reduced the growth rate of SiO_(2)-TGO by nearly twoorders of ***,its thickness decreased by more than 70%after 300 h of exposure.A diffusioncontrolled oxi.ation mechanism indicates that the modified dense surface is equivalent to an initial SiO_(2)layer with a specificthickness,causing a shift in the oxi.ation time and increasing the oxi.ation *** research provides valuableinsights for designing Si-based EBC with improved lifetimes.

关键词： environmental barrier coating(EBC) oxi.ation modification diffusion cracking

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高耐热线性环氧树脂的合成及流变特性研究

复合材料科学与工程 2024年第2期 20-26,34页

作者：张相昌王钧陈晞武汉理工大学材料科学与工程学院武汉430070

通过N-苯基马来酰亚胺(N-PMI)与4,4′-二氨基二苯甲烷(DDM)迈克尔加成反应合成了一种改性二元胺(PDP),并与双酚A型环氧树脂(EP)反应制备了线性环氧树脂。通过核磁共振氢谱(HNMR)、红外光谱法(FTIR)和差式扫描量热法(DSC)研究了PDP的化... 详细信息

通过N-苯基马来酰亚胺(N-PMI)与4,4′-二氨基二苯甲烷(DDM)迈克尔加成反应合成了一种改性二元胺(PDP),并与双酚A型环氧树脂(EP)反应制备了线性环氧树脂。通过核磁共振氢谱(HNMR)、红外光谱法(FTIR)和差式扫描量热法(DSC)研究了PDP的化学结构与性质,并通过DSC,FTIR和凝胶渗透色谱法(GPC)研究了线性环氧树脂耐热性(T_(g))及流变特性。结果表明:随着反应时间延长,EP/PDP(1∶1摩尔比)树脂体系黏度由0.55 Pa·s增至57 Pa·s,T_(g)由55℃升至120℃,平均分子质量由4651增至25096;随着温度的降低,体系黏度由200℃的0.55 Pa·s增加至140℃的60 Pa·s。不同比例EP/PDP树脂体系的T_(g)随PDP过量的比例增大而升高,当EP∶PDP为0.8∶1时,T_(g)为121℃,在相同反应时间,体系黏度随PDP过量比例的增大而增大。

关键词：改性二元胺线性环氧树脂 4,4′-二氨基二苯甲烷 N-苯基马来酰亚胺复合材料

Aerodynamic/stealth design of S-duct inlet based on discrete adjoint method

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Applied Mathematics and Mechanics(English Edition) 2024年第4期45卷 725-746页

作者： jun DENG Ke ZHAO Lin ZHOU Wei ZHANG Bowen SHU Jiangtao HUANG Zhenghong GAO School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Aerospace Technology Institute of China Aerodynamic Research and Development CenterMianyang 621000Sichuan ProvinceChina

It is a major challenge for the airframe-inlet design of modern combat aircrafts,as the flow and electromagnetic wave propagation in the inlet of stealth aircraft are very *** this study,an aerodynamic/stealth optimization design method for an S-duct inlet is *** upwind scheme is introduced to the aerodynamic adjoint equation to resolve the shock wave and flow *** multilevel fast multipole algorithm(MLFMA)is utilized for the stealth adjoint equation.A dorsal S-duct inlet of flying wing layout is optimized to improve the aerodynamic and stealth *** the aerodynamic and stealth characteristics of the inlet are effectively ***,the optimization results are analyzed,and it shows that the main contradiction between aerodynamic characteristics and stealth characteristics is the centerline and crosssectional *** S-duct is smoothed,and the cross-sectional area is increased to improve the aerodynamic characteristics,while it is completely opposite for the stealth *** radar cross section(RCS)is reduced by phase cancelation for low frequency *** method is suitable for the aerodynamic/stealth design of the aircraft airframe-inlet system.

关键词： S-duct inlet aerodynamic/stealth optimization design discrete adjoint upwind scheme multilevel fast multipole algorithm(MLFMA)

Simulation study on cuttings transport of the backreaming operation for long horizontal section wells

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Petroleum Science 2024年第2期21卷 1149-1170页

作者： Yu-Fei Chen Hui Zhang Wen-xi. Wu jun Li Yong Ouyang Zong-Yu Lu De-xi. Ma Yong-Chuan Wu jun-Bo Liu Ke-Rou Liu Zhuo-xi. Dong China University of Petroleum(Beijing) Beijing102249China Beijing Normal University at Zhuhai Experimental and Practical Education Innovation CenterZhuhai519087GuangdongChina Oil&Gas Technology Research Institute of PetroChina Changqing Oilfield Company Xi'an710016ShaanxiChina PetroChina xi.jiang Oilfield Company Karamay834002XinjiangChina China Oilfield Services Ltd. Tianjin300459China

The backreaming operation plays a significant role in safe drilling for horizontal wellbores, while it may cause severe stuck pipe accidents. To lower the risk of the stuck pipe in backreaming operations, the mechanism of cuttings transport needs to be carefully investigated. In this research, a transient cuttings transport with multiple flow patterns model is developed to predict the evolution of cuttings transported in the annulus while backreaming. The established model can provide predictions of the distribution of cuttings bed along the wellbore considering the bulldozer effect caused by large-size drilling tools(LSDTs). The sensitivity analyses of the size of LSDTs, and backreaming operating parameters are conducted in Section 4. And a new theory is proposed to explain the mechanism of cuttings transport in the backreaming operation, in which both the bit and LSDTs have the “cleaning effect” and “plugging effect”.The results demonstrate that the cuttings bed in annuli is in a state of dynamic equilibrium, but the overall trend and the distribution pattern are obvious. First, larger diameters and longer drilling tools could lead to a higher risk of the stuck pipe. Second, we find that it is not the case that the higher flow rate is always better for hole cleaning, so three flow-rate intervals are discussed separately under the given conditions. When the “dangerous flow rate”(35 L/s in Case 4),the higher the flow rate, the better the cleaning effect of cuttings beds. Third, an interval of tripping velocity called “dangerous velocity” is proposed, in which the cuttings bed accumulation near the LSDTs is more serious than

关键词： Backreaming Stuck pipe Hole cleaning Transient solid transport Multiple flow patterns

Intelligent geochemical interpretation of mass chromatograms:Based on convolution neural network

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Petroleum Science 2024年第2期21卷 752-764页

作者： Kai-Ming Su jun-Gang Lu Jian Yu Zi-xi.g Lu Shi-Jia Chen Hubei Key Laboratory of Petroleum Geochemistry and Environment Wuhan430100HubeiChina College of Resources and Environment Yangtze UniversityWuhan430100HubeiChina School of Geoscience and Technology Southwest Petroleum UniversityChengdu610500SichuanChina Changqing Oilfield Company PetroChinaXi'an710021ShaanxiChina

Gas chromatography-mass spectrometry(GC-MS)is an extremely important analytical technique that is widely used in organic *** is the only approach to capture biomarker features of organic matter and provides the key evidence for oil-source correlation and thermal maturity ***,the conventional way of processing and interpreting the mass chromatogram is both timeconsuming and labor-intensive,which increases the research cost and restrains extensive applications of this *** overcome this limitation,a correlation model is developed based on the convolution neural network(CNN)to link the mass chromatogram and biomarker features of samples from the Triassic Yanchang Formation,Ordos Basin,*** this way,the mass chromatogram can be automatically *** research first performs dimensionality reduction for 15 biomarker parameters via the factor analysis and then quantifies the biomarker features using two indexes(*** and PMI)that represent the organic matter thermal maturity and parent material type,***,training,interpretation,and validation are performed multiple times using different CNN models to optimize the model structure and hyper-parameter setting,with the mass chromatogram used as the input and the obtained MI and PMI values for supervision(label).The optimized model presents high accuracy in automatically interpreting the mass chromatogram,with R2values typically above 0.85 and0.80 for the thermal maturity and parent material interpretation results,*** significance of this research is twofold:(i)developing an efficient technique for geochemical research;(ii)more importantly,demonstrating the potential of artificial intelligence in organic geochemistry and providing vital references for future related studies.

关键词： Organic geochemistry Biomarker Mass chromatographic analysis Automated interpretation Convolution neural network Machine learning

大学生如何解码群团组织的新媒体传播形式和内容——以Z组织的B站账号为例

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清华大学教育研究 2024年第4期45卷 69-81页

作者：邵颖王熙苏君阳北京师范大学教育学部

借鉴霍尔的解码理论和意义接合理论，对22名大学生开展访谈，探讨大学生对于群团组织Z在B站的传播形式和内容的解码特征及形塑解码的力量。研究发现，大学生的解码呈现“去政治性”,这使得将传播活动视为“追求‘傻乐’的审美化景观”... 详细信息

借鉴霍尔的解码理论和意义接合理论，对22名大学生开展访谈，探讨大学生对于群团组织Z在B站的传播形式和内容的解码特征及形塑解码的力量。研究发现，大学生的解码呈现“去政治性”,这使得将传播活动视为“追求‘傻乐’的审美化景观”和“彰显精英品位的知识解读”这两种看似矛盾的话语被接合在一起。一方面，新自由主义下的个人主义和泛娱乐主义导致了大学生政治冷漠与唯快乐是从的“傻乐”状态的形成。另一方面，在长期应试教育和技治主义的综合作用下，大学生虽强调硬核知识和严肃分析的价值，却难以将政治知识联系生活实践，更倾向于站在精英立场上认识政治和社会。究其原因，B站平台运营的商业逻辑和“过滤泡效应”强化了“去政治性”,不仅助长了大学生对于政治议题与公共事务的冷漠情绪，还滋长了个人主义与“傻乐主义”。为提升受众的思想政治素养，群团组织应坚持走群众路线，增强政治知识传播的回应性与有效性；对传播内容的政治意义进行深度阐释，提升受众政治参与的积极性。

关键词：去政治性大学生新媒体传播解码接合

来源：博看期刊

Association between Long-Term Exposure to PM_(2.5) Inorganic Chemical Compositions and Cardiopulmonary Mortality: A 22-Year Cohort Study in Northern China

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Environment & Health 2024年第8期2卷 530-540页

作者： Hongyue Sun xi.Chen Wenzhong Huang Jing Wei Xueli Yang Anqi Shan Liwen Zhang Honglu Zhang Jiayu He Chengjie Pan Jingjing Li Jing Wu Tong Wang Jie Chen Yuming Guo Shilu Tong Guanghui Dong Nai-jun Tang Department of Occupational and Environmental Health School of Public HealthTianjin Medical UniversityTianjin 300070China Tianjin Key Laboratory of Environment Nutrition and Public Health Tianjin Medical UniversityTianjin 300070China Center for International Collaborative Research on Environment Nutrition and Public Health Tianjin 300070China Key Laboratory of Prevention and Control of Major Diseases in the Population Ministry of EducationTianjin Medical UniversityTianjin 300070China Climate Air Quality Research UnitSchool of Public Health and Preventive MedicineMonash UniversityMelbourne 3004Australia Department of Atmospheric and Oceanic Science Earth System Science Interdisciplinary CenterUniversity of MarylandCollege ParkMaryland 20740United States Shandong Provincial Hospital Affiliated to Shandong First Medical University Ji nan 250021ShandongChina National Center for Chronic and Noncommunicable Disease Control and Prevention Chinese Center for Disease Control and PreventionBeijing 100050China Department of Epidemiology and Biostatistics School of Public HealthTianjin Medical UniversityTianjin 300070China School of Public Health Shanxi Medical UniversityTaiyuan 030001China School of Public Health and Social Work Queensland University of TechnologyBrisbane 4072QLD Australia National Institute of Environmental Health Chinese Centre for Disease Control and PreventionBeijing 100021China Guangdong Provincial Engineering Technology Research Center of Environmental Pollution and Health Risk Assessment Department of Occupational and Environmental HealthSchool of Public HealthSun Yat-sen UniversityGuangzhou 510080China

Particulate matter with diameters≤2.5μm(PM_(2.5))has been identified as a significant air pollutant contributing to premature ***,the specific compositions within PM_(2.5) that play the most crucial role remain unclear,especially in areas with high pollution *** study aims to investigate the individual and joint mortality risks associated with PM_(2.5) inorganic chemical compositions and identify primary *** 1998,we conducted a prospective cohort study in four northern Chinese cities(Tianjin,Shenyang,Taiyuan,and Rizhao).Satellite-based machine learning models calculated PM_(2.5) inorganic chemical compositions,including sulfate(SO_(4)^(2–)),nitrate(NO_(3)^(–)),ammonium(NH_(4)^(+)),and chloride(Cl^(-)).A time-varying Cox proportional hazards model was applied to analyze associations between these compositions and cardiorespiratory mortality,encompassing nonaccidental causes,cardiovascular diseases(CVDs),nonmalignant respiratory diseases(RDs),and lung *** quantile-based g-computation model evaluated joint exposure effects and relative contributions of the *** analysis was used to identify vulnerable *** 785,807 person-years of follow-up,5812(15.5%)deaths occurred from nonaccidental causes,including 2932(7.8%)from all CVDs,479(1.3%)from nonmalignant RDs,and 552(1.4%)from lung *** interquartile range(IQR)increase in SO_(4)^(2–)was associated with mortality from nonaccidental causes(hazard ratio:1.860;95%confidence interval:1.809,1.911),CVDs(1.909;1.836,1.985),nonmalignant RDs(2.178;1.975,2.403),and lung cancer(1.773;1.624,1.937).In the joint exposure model,a simultaneous rise of one IQR in all four compositions increased the risk of cardiorespiratory mortality by at least 36.3%,with long-term exposure to SO_(4)^(2–)contributing the most to nonaccidental and cardiopulmonary *** with higher incomes and lower education levels were found to be more vulnerable.

关键词： PM_(2.5)inorganic chemical compositions mortality cohort study cardiorespiratory disease joint association

Design and assembly of a nested imaging X-ray telescope for the Hot Universe Baryon Surveyor mission

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Astronomical Techniques and Instruments 2024年第3期1卷 157-165页

作者： jun Yu Ruohui xi.n xi.oqiang Wang Yifan Wang Zhanshan Wang Wei Zhang Yibo Cai Jing Yang xi.Lu Wei Wang Wei Cui Institute of Precision Optical Engineering Tongji UniversityShanghai 200092China Shanghai Institute of Satellite Engineering Shanghai 201109China Department of Astronomy Tsinghua UniversityBeijing 100084China

The Hot Universe Baryon Surveyor (HUBS) mission will carry a nested X-ray telescope capable of observing an energy range from 0.5 keV to 2 keV to study hot baryon evolution. In this paper, we report the latest progress in the design and construction of nested X-ray telescopes which were designed to use a three-stage conic-approxi.ation type assembly to simplify the manufacturing process. The mirror substrate is made using the thermal glass slumping method, with mirrors characterized by a root-mean-square roughness of 0.3 nm, with expected high reflectivity and good thermal stability. We also discuss methods of telescope construction and conduct a deformation analysis of the manufactured mirror. The in situ measurement system program is developed to guide the telescope assembly process.

关键词： Nested X-ray telescope Thermal glass slumping Telescope assembly In situ measurement