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环境监管体制困境的破解对策探讨

环境科学与管理 2012年第B12期37卷 22-25页

作者：戴维基何强重庆市环境保护局重庆401147

环境保护垂直管理体制存在不能从根本上摆脱地方政府干预,无法破除环境保护职能分散,弱化地方政府职责,降低地方政府的积极性等弊端。破解环境监管体制困境,需进一步深化环境保护"大部门制"改革,以提高行政效率,以加强环境监管为重点,... 详细信息

环境保护垂直管理体制存在不能从根本上摆脱地方政府干预,无法破除环境保护职能分散,弱化地方政府职责,降低地方政府的积极性等弊端。破解环境监管体制困境,需进一步深化环境保护"大部门制"改革,以提高行政效率,以加强环境监管为重点,深化纵向关系,健全公众参与体系,藉此改善环境保护与社会发展的关系。

关键词：环保体制困境对策

Mo_(2)C-TiN_(0.3)复合材料的高温高压制备及性能

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金刚石与磨料磨具工程 2024年第4期44卷 440-448页

作者：邹芹王宽李艳国戴伟绩罗永安燕山大学机械工程学院河北秦皇岛066004 燕山大学亚稳材料制备技术与科学国家重点实验室河北秦皇岛066004

将Mo_(2)C和TiN_(0.3)粉体采用机械合金化和高温高压烧结相结合的方法进行分层烧结,并制备30%Mo_(2)C-70%TiN_(0.3)的烧结体复合材料,分析Mo_(2)C-TiN_(0.3)烧结体的物相组成、微观组织结构及力学性能。结果表明:Mo_(2)C和TiN_(0.3)间... 详细信息

将Mo_(2)C和TiN_(0.3)粉体采用机械合金化和高温高压烧结相结合的方法进行分层烧结,并制备30%Mo_(2)C-70%TiN_(0.3)的烧结体复合材料,分析Mo_(2)C-TiN_(0.3)烧结体的物相组成、微观组织结构及力学性能。结果表明:Mo_(2)C和TiN_(0.3)间存在明显的相互扩散,且形成了2层不同的扩散层;随着烧结温度不断升高,Mo_(2)C-TiN_(0.3)烧结体的晶粒尺寸逐渐变大,会导致烧结体的机械性能变差;在烧结过程中有高硬高脆的MoC生成,能够维持Mo_(2)C-TiN_(0.3)烧结体的硬度在19.0~20.0 GPa,但会降低其断裂韧性。

关键词： TiN_(0.3) Mo_(2)C 扩散高温高压烧结机械合金化

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高熵合金制备技术研究新进展

河南科学 2024年第11期42卷 1561-1569页

作者：范小康吴兵赵翠娇戴伟绩马鞍山钢铁股份有限公司安徽马鞍山243000 江苏科技大学材料科学与工程学院江苏镇江212100

高熵合金因其独特的结构和性能得到各领域广泛的关注.与传统合金相比,高熵合金在组成、结构和性能方面表现出独特的优势.从高熵合金的成分、结构和制备方法等方面讨论了其性能变化规律,并且系统地总结当前研究中高熵合金的制备技术进展... 详细信息

高熵合金因其独特的结构和性能得到各领域广泛的关注.与传统合金相比,高熵合金在组成、结构和性能方面表现出独特的优势.从高熵合金的成分、结构和制备方法等方面讨论了其性能变化规律,并且系统地总结当前研究中高熵合金的制备技术进展.目前高熵合金制备方法包括真空电弧熔炼、感应熔炼、悬浮熔炼、磁控溅射、激光熔覆、电化学法、机械合金化、熔盐法和溶液燃烧合成等.不同形态高熵合金的制备技术特征明显,有显著区别,其技术的发展也相对独立.此外,对相关制备技术得到的高熵合金材料在其研究领域的应用也进行了介绍,并在此基础上对高熵合金制备技术的发展趋势进行展望.

关键词：高熵合金制备技术熔炼磁控溅射溶液燃烧

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中立型时滞微分方程的离散分析的振动性

太原工业大学学报 1994年第1期25卷 37-40页

作者：戴维纪张玉珠太原工业大学山西经济管理学院

本文考虑时滞差分方程Δ（ｘ＿ｎ—ｃｘ＿（ｎ－１））＋ｐ＿ｎｘ＿（ｎ－ｋ１）—ｑｘ＿（ｎ－ｋ２）＝０，ｎ＝０，１，２……的解的振动性，得出其振动的两个充分条件。

关键词：中立型时滞微分方程振动性

Tantalum oxide barrier in magnetic tunnel junctions

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Journal of University of Science and Technology Beijing 2004年第4期11卷 324-328页

作者： GuanghuaYu TingtingRen weiji JiaoTeng FengwuZhu MaterialsScienceandEngineeringSchool UniversityofScienceandTechnologyBeijingBeijing100083China

Tantalum as an insulating barrier can take the place of Al in magnetic tunneljunctions (MTJs). Ta barriers in MTJs were fabricated by natural oxidation. X-ray photoelectronspectroscopy (XPS) was used to characterize the oxidation states of Ta barrier. The experimentalresults show that the chemical state of tantalum is pure Ta^(5+) and the thickness of the oxide is1.3 nm. The unoxidized Ta in the barrier may chemically reacted with NiFe layer which is usuallyused in MTJs to form an intermetallic compound, NiTa_2. A magnetic 'dead layer' could be produced inthe NiFe/Ta interface. The 'dead layer' is likely to influence the spinning electron transport andthe magnetoresistance effect.

关键词： magnetic tunnel junctions (MTJs) insulating barrier TaO_x X-rayphotoelectron spectroscopy (XPS)

Research regarding coal-bed wellbore stability based on a discrete element model

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Petroleum Science 2014年第4期11卷 526-531页

作者： Zhu Xiaohua Liu weiji Jiang Jun School of Mechanical Engineering Southwest Petroleum University

Wellbore instability is a key problem restricting efficient production of coal-bed methane. In order to perform thorough and systematic research regarding coal-bed wellbore stability problems, a new discrete element model which fully considers the features of cleat coal-beds is established based on the Kirsch equation. With this model, the safe pipe tripping speed, drilling fluid density window and coal- bed collapse/fracture pressure are determined; in addition, the relationships between pipe tripping speed and pipe size, cleat size, etc. and wellbore stability are analyzed in the coal-bed drilling and pipe tripping processes. The case studies show the following results： the wellbore collapses （collapse pressure： 4.33 MPa） or fractures （fracture pressure： 12.7 MPa） in certain directions as a result of swab or surge pressure when the pipe tripping speed is higher than a certain value; the cleat face size has a great influence on wellbore stability, and if the drilling fluid pressure is too low, the wellbore is prone to collapse when the ratio of the face cleat size to butt cleat size is reduced; however, if the drilling fluid pressure is high enough, the butt cleat size has no influence on the wellbore fracture; the factors influencing coal-bed stability include the movement length, pipe size, borehole size.

关键词： Coal-bed methane, wellbore stability, discrete element model, pipe tripping wellborecollapse

Current therapeutic landscape and resistance mechanisms to larotrectinib

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Cancer Biology & Medicine 2023年第12期20卷 967-971页

作者： weiji Xie Jiaqian Xu Suying Lu Yizhuo Zhang Department of Pediatric Oncology State Key Laboratory of Oncology in South ChinaGuangdong Provincial Clinical Research Center for CancerCollaborative Innovation Center for Cancer MedicineSun Yat-sen University Cancer CenterGuangzhou 510060China Young Talents Program of Sun Yat-sen University Cancer Center Guangzhou 510060China

Cancer has emerged as the leading cause of mortality worldwide and is driven by numerous intricate *** tropomyosin receptor kinase (TRK) proto-oncogene family consists of the TRKA,TRKB,and TRKC transmembrane receptors,which are encoded by the NTRK1,NTRK2,and NTRK3 genes,respectively,and are widely expressed in the nervous system and many non-neuronal tissue *** signaling plays crucial roles in neuronal development,differentiation,and diverse neuronal functions,such as neuronal survival,synapse formation and plasticity,and axon and dendrite formation,in physiologic processes3.

关键词： mortality Cancer landscape

Qualitative and quantitative detection using eDNA technology: A case study of Fenneropenaeus chinensis in the Bohai Sea

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Aquaculture and Fisheries 2020年第3期5卷 148-155页

作者： Miao Lia Xiujuan Shan weiji Wang Xiaosong Ding Fangqun dai Ding Lv Huanhuan Wu Key Laboratory of Sustainable Development of Ma Fisheries Ministry of Agriculture and Rural AffairsShandong Provincial Key Laboratory of Fishery Resources and Ecological EnvironmentYellow Sea Fisheries Research InstituteChinese Academy of Fishery SciencesQingdao266071China Laboratory for Marine Fisheries Science and Food Production Processes Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao266237China

Accurate knowledge of species distributions and population dynamics is the basis for conservation ***, for certain species with unique life histories and very small populations, monitoring species distributions and population dynamics is extremely difficult. Recently, newly developed eDNA technology has been widely used in species monitoring, biodiversity assessments, and biomass assessments. In this research, we studied Fenneropenaeus chinensis in the Bohai Sea. We used a 0.45 μm glass fiber filter combined with a vacuum to filter 2 L seawater samples for eDNA enrichment from 54 stations in June and 60 stations in August. A DNeasy Blood and Tissue kit was used to extract the eDNA. After DNA extraction, the specific primers and probes of the mitochondrial DNA COI gene of F. chinensis were designed. Real-time quantitative PCR was used to qualitatively and quantitatively analyze the eDNA in the Bohai Sea. The temporal and spatial distribution of F. chinensis was detected by the eDNA technique. The relationship between the eDNA copy number and trawl-netted F. chinensis biomass was explored. The applicability and sensitivity of eDNA technology in marine crustacean research were verified. The results showed that the mtDNA COI gene of F. chinensis was successfully amplified in the 54 water samples collected in June, and the detection rate reached 100%. Detections occurred in only 23 of the 60 stations sampled in August. F. chinensis had a detection rate of only 38%. The copy number of eDNA obtained by realtime PCR was fitted to the density of F. chinensis captured by bottom trawling. There was not a significant positive correlation between copy number and biomass. The results obtained through this research will provide a method and theoretical basis for the application of eDNA technology in marine crustacean research.

关键词： Bohai Sea eDNA Fenneropenaeus chinensis Spatial and temporal distribution Biomass

Numerical and experimental investigation on hydraulic-electric rock fragmentation of heterogeneous granite

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International Journal of Mining Science and Technology 2024年第1期34卷 15-29页

作者： Xiaohua Zhu Ling He weiji Liu Yunxu Luo Youjian Zhang Wuji Tang School of Mechatronic Engineering Southwest Petroleum UniversityChengdu 610500China School of Mechanical Engineering Sichuan University of Science and EngineeringYibin 643002China

Hydraulic-electric rock fragmentation(HERF)plays a significant role in improving the efficiency of high voltage pulse rock ***,the underlying mechanism of HERF remains *** this study,considering the heterogeneity of the rock,microscopic thermodynamic properties,and shockwave time domain waveforms,based on the shockwave model,digital imaging technology and the discrete element method,the cyclic loading numerical simulations of HERF is achieved by coupling electrical,thermal,and solid mechanics under different formation temperatures,confining pressure,initial peak voltage,electrode bit diameter,and loading ***,the HERF discharge system is conducive to the laboratory experiments with various electrical parameters and the resulting broken pits are numerically reconstructed to obtain the geometric *** results show that,the completely broken area consists of powdery rock *** the pre-broken zone,the mineral cementation of the rock determines the transition of type CⅠcracks to type CⅡand type CⅢ***,the peak pressure of the shockwave increased with initial peak voltage but decreased with electrode bit diameter,while the wave front time ***,increasing well depth,formation temperature and confining pressure augment and inhibit HERF,but once confining pressure surpassed the threshold of 60 MPa for 152.40,215.90,and 228.60 mm electrode bits,and 40 MPa for 309.88 mm electrode bits,HERF is ***,for the same kind of rock,the volume and width of the broken pit increase with higher initial peak voltage and rock fissures will promote ***,the electrode drill bit with a 215.90 mm diameter is more suitable for drilling pink *** research contributes to a better microscopic understanding of HERF and provides valuable insights for electrode bit selection,as well as the optimization of circuit parameters for HERF technology.

关键词： Hydraulic-electric rock fragmentation Shockwave Thermodynamics Microcracks Weak Linear Parallel Bond Model