检索结果-南通市图书馆

基于机器学习方法研究气象及排放变化对长三角地区主要城市大气污染物的影响

在线全文

学校读者我要写书评

暂无评论

环境科学 2023年第11期44卷 5879-5888页

作者：付文星黄琳丁嘉豪秦墨梅于兴娜谢放尖胡建林南京信息工程大学环境科学与工程学院江苏省大气环境监测与污染控制高技术研究重点实验室江苏省大气环境与装备技术协同创新中心南京210044 南京信息工程大学长望学院南京210044 南京信息工程大学气象灾害预报预警与评估协同创新中心中国气象局气溶胶与云降水重点开放实验室南京210044 南京生态环境保护科学研究院南京210093

选取2015~2021年长三角地区4个代表性城市污染物浓度,利用机器学习的气象归一化方法解耦气象因素对污染物的影响,量化气象和排放对污染物浓度变化的贡献.结果表明,长三角地区PM_(2.5)、NO_(2)和SO_(2)排放下降影响贡献较大(57.2%~68.2%... 详细信息

选取2015~2021年长三角地区4个代表性城市污染物浓度,利用机器学习的气象归一化方法解耦气象因素对污染物的影响,量化气象和排放对污染物浓度变化的贡献.结果表明,长三角地区PM_(2.5)、NO_(2)和SO_(2)排放下降影响贡献较大(57.2%~68.2%、80.7%~94.6%和81.6%~96.1%),抵消了气象因素带来的不利影响,致使污染物浓度降低.而气象条件对于臭氧日最大8 h(MDA8O_(3))的贡献强于其他污染物(23.5%~42.1%),其中气象因素促进污染物浓度上升(4.7%),排放变化促进污染物浓度下降(-3.2%).NO_(2)和MDA8O_(3)在2019~2021年降幅更快,主要原因是2019~2021年排放起到较2015~2018年更强的促进污染物浓度降低作用.PM_(2.5)和SO_(2)在2019~2021年的降幅较2015~2021年整体有所减弱.基于机器学习的气象归一化方法可以解耦气象对污染物的影响,量化排放变化对污染物浓度的影响,为评估污染控制政策的有效性提供了很好的研究手段.

关键词：机器学习气象归一化大气污染物长期趋势随机森林模型

法尔康盆地基于重力资料的构造特征分析与油气有利区预测

在线全文

学校读者我要写书评

暂无评论

石油物探 2022年第6期61卷 1127-1138页

作者：薛健袁炳强邢锦程张春灌冯旭亮张欢贾洪杨西安石油大学地球科学与工程学院陕西西安710065 陕西省油气成藏地质学重点实验室陕西西安710065 胜利油田鲁明公司山东东营257000

法尔康盆地位于委内瑞拉西北部,具有良好的油气资源前景。前人在盆地进行的勘探工作主要集中在盆地中部及东北部较小区域内,盆地整体勘探程度低且地震资料缺乏。为了研究盆地构造特征,预测油气有利区,基于地面、船测和卫星重力数据,结... 详细信息

法尔康盆地位于委内瑞拉西北部,具有良好的油气资源前景。前人在盆地进行的勘探工作主要集中在盆地中部及东北部较小区域内,盆地整体勘探程度低且地震资料缺乏。为了研究盆地构造特征,预测油气有利区,基于地面、船测和卫星重力数据,结合盆地实际地质背景,应用莫霍面改正和倾斜角处理等方法新推断了整个盆地的断裂构造;综合应用Parker法和相关分析法计算了盆地的基底深度;利用盆地模拟软件模拟分析了不同构造单元烃源岩热演化的差异性,对盆地进行了构造单元划分及油气有利区预测。研究结果表明,法尔康盆地主要发育NE和NW向的控制盆地内构造走向和地层发育的两组断裂,盆地可以划分为6个次级构造单元,其中,西部、北部凹陷和中部隆起区地层发育较为齐全。盆地内中部隆起区及两侧的凹陷区烃源岩热演化存在差异,中部隆起区白垩系烃源岩与始新统烃源岩进入生烃门限的时间明显早于其它地区,油气地质条件良好,为油气有利区。

关键词：重力异常断裂构造基底特征热史模拟油气有利区法尔康盆地

TiO^(2)electron transport bilayer for all-inorganic perovskite photodetectors with remarkably improved UV stability toward imaging applications

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第16期75卷 39-47页

作者： Ye yuan Zhong jia Genghua Yan Zhuowei Li Jinliang Li Min Kuang Bangqi jiang Longlong Zeng Likun Pan Wenjie Mai Siyuan Laboratory Guangdong Provincial Engineering Technology Research Center of Vacuum Coating Technologies and New Energy MaterialsDepartment of PhysicsJinan UniversityGuangzhouGuangdong 510632China Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications Jinan University.GuangzhouGuangdong 510632China Shanghai Key Laboratory of Magnetic Resonance School of Physics and Electronic ScienceEast China Normal University3663 N.Zhongshan Rd.Shanghai200062China Guangdong Institute of New Materials Guangdong Academy of SciencesGuangzhou510650China Institute of Solar Energy Systems Guangdong Provincial Key Laboratory of Photovoltaic TechnologySchool of PhysicsSun Yat-sen UniversityGuangzhou510006China

High ultraviolet(UV)stability and low dark current(Idark)are necessary for high-quality perovskite photodetectors(PDs).TiO^(2)thin film is known as effective electron-transport-layer(ETL)for perovskite devices.However,common spin-coated TiO^(2)ETLs endow many surface defects and have strong UV photocatalytic effect to decompose perovskite materials,resulting in inferior stability of devices.In this work,TiO^(2)bilayer film(Bi-TiO^(2))has been fabricated by combining spin-coating and atomic-layer-deposition process and its positive effects on UV stability and Idarkof Cs2 AgBiBr6-based PDs have been revealed for the first time.It is demonstrated that Bi-TiO^(2)possesses fewer surface defects and smoother morphology with type II band alignment,which is beneficial to suppress photocatalytic activity of TiO^(2)and reduce carrier recombination at the interface.After accelerated strong UV aging treatment,the PD with Bi-TiO^(2)maintains excellent performance,whereas the PD with spin-coated TiO^(2)film dramatically deteriorate with on-off ratio drops from~102 to~2.Besides,the Idarkof PD remarkably decreases from~10^(-8) A to~10^(-10) A after bilayer optimization.Furthermore,we have integrated the corresponding PDs into a self-built imaging system adopting diffuse reflection mode.This work suggests a feasible approach to fabricate TiO^(2)/Cs2 AgBiBr6-based PDs with remarkable UV tolerance for imaging applications.

关键词： TiO_(2)bilayer film All-Iinorganic perovskite Photodetector UV stability Atomic-layer-deposition Reflective imaging

Direct synthesis of high-quality perovskite nanocrystals on a flexible substrate and deterministic transfer

在线全文

学校读者我要写书评

暂无评论

Science Bulletin 2018年第23期63卷 1576-1582页

作者： Yilun Wang xing Cheng Kai yuan Yi Wan Pan Li Yuhao Deng Haoran Yu Xiaolong Xu Yi Zeng Wanjin Xu Yanping Li Renmin Ma Kenji Watanabe Takashi Taniguchi Yu Ye Lun Dai State Key Laboratory for Artificial Microstructure & Mesoscopic Physics School of PhysicsPeking UniversityBeijing 100871China Collaborative Innovation Center of Quantum Matter Beijing 100871China National Institute for Materials Science 1-1NamikiTsukuba 305-0044Japan

Solid-state perovskite nanocrystals are promising coherent light sources, as there is optical feedback within the crystal structure. In order to utilize the high performance of perovskites for on-chip applications, or observe new physical phenomena, these crystals must be integrated with pre-fabricated electronic or photonic structures. However, the material's fragility has made the deterministic transfer a great challenge thus far. Here, we report the first deterministic transfer of perovskite nanocrystals with sub-micron accuracy. Cesium lead halide(CsPbI_3) nanocrystals were directly synthesized on flexible polydimethylsiloxane(PDMS) stamps via chemical vapor deposition(CVD) and subsequently transferred onto arbitrary substrates/structures. We demonstrated the transfer of a CsPbI_3 crystalline nanoplate(NP)onto an 8 mm fiber core and achieved single-mode whispering gallery mode lasing. Our method can be extended to a variety of other arbitrary substrates(e.g., electrodes, photonic structures, micromechanical systems), laying the foundations for previously unattainable opportunities in perovskites-based devices.

关键词： Deterministic transfer CsPbI3 nanocrystals PDMS substrate CVD

Genetic Improvement of Root Growth Contributes to Efficient Phosphorus Acquisition in maize (Zea mays L.)

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Agriculture 2013年第6期12卷 1098-1111页

作者： ZHANG Yi-kai CHEN Fan-jun CHEN Xiao-chao LONG Li-zhi GAO Kun yuan Li-xing ZHANG Fu-suo MI Guo-hua Laboratory of Plant-Soil Interactions Ministry of Education/Center for Resources Environment and Food Security College of Resources and Environmental Science China Agricultural University

Maize plants adapt to low phosphorus （P） stress by increasing root growth. It is of importance to know the extent to which genetic improvement of root growth can enhance P acquisiton. In the present study, the contribution of root growth improvement to efficient P acquisition was evaluated in two soils using T149 and T222, a pair of near isogenic maize testcrosses which were derived from a backcross BC 4 F 3 population. T149 and T222 showed no difference in shoot biomass and leaf area under normal growth conditions, but differed greatly in root growth. T149 had longer lateral roots and a larger root surface area compared to T222. In calcareous soil, when P was insufficient, i.e., when P was either supplied as KH 2 PO 4 at a concentration of 50 mg P kg-1 soil, or in the form of Phy-P, Ca3-P or Ca10-P, a 43% increase in root length in T149 compared to T222 resulted in an increase in P uptake by 53%, and shoot biomass by 48%. In acid soil, however, when P supply was insufficient, i.e., when P was supplied as KH 2 PO 4 at a concentration of 100 mg P kg-1 soil, or in the form of Phy-P, Fe-P or Al-P, a 32% increase in root length in T149 compared to T222 resulted in an increase in P uptake by only 12%, and shoot biomass by 7%. No significant differences in the exudation of organic acids and APase activity were found between the two genotypes. It is concluded that genetic improvement of root growth can efficiently increase P acquisition in calcareous soils. In acid soils, however, improvements in the physiological traits of roots, in addition to their size, seem to be required for efficient P acquisition.

关键词： P efficiency roots low phosphorus calcareous soil acid soil maize

Ionic Liquid-based Microwave-assisted Liquid-liquid Microextraction and High Performance Liquid Chromatography Determination of Sulfonamides from Animal Oils

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2013年第4期29卷 647-652页

作者： FENG Xu-dong LIANG Fang-hui SU Rui WU Li-jie LI Xue-yuan WANG xing-hua ZHANG Han-qi YU Ai-min College of Chemistry Jilin University Changehun 130012 P. R. China Department of Pharmacy Changchun Medical College Changchun 130117 P. R. China

The authors performed ionic liquid-based microwave-assisted liquid-liquid microextraction（IL-based MALLME） coupled with high performance liquid chromatographic separation for the determination of 6 sulfonamides （SAs） from animal oils. The target analytes were extracted from animal oil samples with sodium hydroxide solution containing 1-butyl-3-methylimidazolium tetrafluoroborateand as the extraction solvent under microwave irradiation. The experimental parameters of the IL-based MALLME, including types of ILs, volume of IL, amount of ion-pairing agent（NHaPF6）, pH value of sample solution, and extraction temperature and time were evaluated. The limits of detection and quantification obtained were in a range of 0.4--0.5μg/kg and a range of 1.2--1.8μg/kg, respectively. The accuracy of the method was evaluated by analyzing five spiked animal oil samples at two fortified levels（5 and 50μg/kg）, and the recoveries of SAs varied from 81.4% to 114.5% with relative standard deviations ranging from 0.8% to 9.0%.

关键词： Ionic liquid-based microwave-assisted liquid-liquid microextraction（IL-based MALLME） High perfor-mance liquid chromatography（HPLC） Sulfonamide Animal oil

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

针灸干预阿尔茨海默病作用机制的研究进展

针刺研究 2022年第4期47卷 362-368页

作者：魏玉婷朱田田贾静严兴科甘肃中医药大学针灸推拿学院兰州730000

阿尔茨海默病(AD)是一种老年人常见的神经退行性疾病。研究表明,针灸能有效减轻AD的症状,延缓病情进展,其作用机制研究也不断深入。本文总结了近5年针灸干预AD的机制研究资料,结果显示,针灸干预AD的作用机制与调节相关蛋白的表达、抑制... 详细信息

阿尔茨海默病(AD)是一种老年人常见的神经退行性疾病。研究表明,针灸能有效减轻AD的症状,延缓病情进展,其作用机制研究也不断深入。本文总结了近5年针灸干预AD的机制研究资料,结果显示,针灸干预AD的作用机制与调节相关蛋白的表达、抑制中枢炎性反应、抵抗氧化应激损伤、调节脑区能量代谢、改善神经元突触可塑性、调控细胞自噬活性水平、抑制神经细胞凋亡密切相关。

关键词：阿尔茨海默病针灸机制研究综述

在线全文

学校读者我要写书评

暂无评论

载人航天USB测控系统及其关键技术

宇航学报 2005年第6期26卷 743-747页

作者：刘嘉兴中国电子科技集团第10研究所成都610036

总结了载人航天USB测控系统的综合化、高可靠性、高测轨精度、抗组合干扰、数字化、大动态控制、目标快速捕获、极化分集接收等关键技术,以及为解决这些关键而采取的技术措施,包括:统一载波信号设计,“五合一”数字载波环,数字测速和测... 详细信息

总结了载人航天USB测控系统的综合化、高可靠性、高测轨精度、抗组合干扰、数字化、大动态控制、目标快速捕获、极化分集接收等关键技术,以及为解决这些关键而采取的技术措施,包括:统一载波信号设计,“五合一”数字载波环,数字测速和测距,随扫斜率判决,高线性调制/解调,FM极化合成跟踪等。经过我国载人航天工程实践的验证,USB测控系统是成功的,其综合性能达到了当时的国际先进水平。

关键词：载人航天统一S频段测控系统(USB) 通信

液态镓合金与铜电极间接触电阻特性与可靠性提升

在线全文

学校读者我要写书评

暂无评论

表面技术 2023年第10期52卷 267-277页

作者：纪越张彦鹏李醒飞张志佳天津工业大学控制科学与工程学院天津300387 天津工业大学天津市电气装备智能控制重点实验室天津300387 天津工业大学材料科学与工程学院天津300387 天津大学精密测试技术及仪器国家重点实验室天津300072

目的针对使用液态金属的电气设备中源极输出电阻波动的抑制问题,分析接触电阻随接触面间接触应力的变化规律,探索电极材料镀膜方法减小膜层电阻变化进而提高接触可靠性。方法理论推导建立了镓合金与铜电极的固液接触电阻理论模型,并... 详细信息

目的针对使用液态金属的电气设备中源极输出电阻波动的抑制问题,分析接触电阻随接触面间接触应力的变化规律,探索电极材料镀膜方法减小膜层电阻变化进而提高接触可靠性。方法理论推导建立了镓合金与铜电极的固液接触电阻理论模型,并据此使用COMSOL Multipyhsics软件仿真了随着接触应力的变化接触电阻的变化情况。使用化学气相沉积法在铜基底上生长碳纳米薄膜来减小膜层电阻对铜电极的影响,并对生长了石墨烯薄膜的电极与镓合金的接触电阻进行了稳定性实验。结果仿真结果表明接触电阻随着接触应力的增加而减小,接触应力较小时的接触电阻变化较大,随着接触应力的不断增加,接触电阻变化也逐渐缓慢,并进行了实验验证;通过调整化学气相沉积法中碳源的通入量来生长更符合电极使用条件的石墨烯薄膜,在6mL/min乙炔流量下生长的石墨烯薄膜接触电阻由未生长石墨烯薄膜的246μΩ减小到165μΩ,减小了镓合金与铜电极间的固液接触电阻,并且自身电阻值增加较小。长期稳定性实验也表明石墨烯薄膜可以有效防护铜电极,并通过相关的接触角实验进一步分析了生长碳纳米薄膜后电极表面润湿性变化。结论铜电极表面生长石墨烯薄膜可以有效防护电极,提高铜基底电极与液态镓合金形成固液接触电阻的稳定性,同时控制接触面的接触应力,可以量化控制接触电阻的数量级。

关键词：气相沉积法接触电阻液态金属接触应力膜层石墨烯