检索结果-南通市图书馆

Pumping-induced Well Hydraulics and Groundwater Budget in a leaky Aquifer System with Vertical Heterogeneity in Aquitard Hydraulic Properties

引用

Acta Geologica Sinica(English Edition) 2024年第2期98卷 477-490页

作者： ZHuANG Chao lÜChenyang YAN long lI Yabing ZHOu Zhifang WANG Jinguo DOu Zhi Walter A.IllMAN School of Earth Sciences and Engineering Hohai UniversityNanjing 211100China School of Geography Earth and Environmental SciencesUniversity of BirminghamBirmingham B152TTU.K. Department of Modern Mechanics University of Science and Technology of ChinaHefei 230027China Department of Earth and Environmental Sciences University of WaterlooOntario N2L 3G1Canada

In groundwater hydrology,aquitard heterogeneity is often less considered compared to aquifers,despite its significant impact on groundwater hydraulics and groundwater resources evaluation.A semi-analytical solution is derived for pumping-induced well hydraulics and groundwater budget with consideration of vertical heterogeneity in aquitard hydraulic conductivity(K)and specific storage(S_(s)).The proposed new solution is innovative in its partitioning of the aquitard into multiple homogeneous sub-layers to enable consideration of various forms of vertically heterogeneous K or S_(s).Two scenarios of analytical investigations are explored:one is the presence of aquitard interlayers with distinct K or S_(s) values,a common field-scale occurrence;another is an exponentially depth-decaying aquitard S_(s),a regional-scale phenomenon supported by statistical *** investigations reveal that a low-K interlayer can significantly increase aquifer drawdown and enhance aquifer/aquitard depletion;a high-S_(s) interlayer can noticeably reduce aquifer drawdown and increase aquitard *** of low-K or high-S_(s) interlayers also significantly impact well hydraulics and groundwater *** the context of an exponentially depth-decaying aquitard S_(s),a larger decay exponent can enhance aquifer *** using current models with a vertically homogeneous aquitard,half the sum of the geometric and harmonic means of exponentially depth-decaying aquitard S_(s) should be used to cal.ulate aquitard depletion and unconfined aquifer leakage.

关键词： hydrogeology aquitard vertical heterogeneity semi-analytical solution well hydraulics groundwater budget

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

HAPNet: a head-aware pedestrian detection network associated with the affinity field

引用

Science China(Information Sciences) 2022年第6期65卷 17-32页

作者： jiali DING Tie l.u Yun ZHAO Zejian YuAN Yuanyuan SHANG College of Information Engineering Capital Normal University College of Artificial Intelligence Xi'an Jiaotong University

Pedestrian detection has made great progress with the rapid development of deep learning, but pedestrian detection under occlusion remains a challenge. To solve the occlusion problem, some research endeavors have been carried out based on visible parts, such as the body, but there is still substantial room for improvement due to the introduction of additional cal.ulation. Aiming to improve the detection performance under occlusion, this paper proposes a head-aware pedestrian detection network(HAPNet) by using the inherent structural relationship between the human body and head. The postprocessing stage is redesigned to include a scoring module and an augmented non-maximum suppression(NMS) ***, HAPNet detects head and body simultaneously through different layers of a feature map. We then propose a head-side affinity model, which can represent the association between the head and body sides. Detection and affinity prediction tasks are implemented through different branches of HAPNet. In the scoring module, the head and body detection scores are fused to match the head-body pairs to improve the detection performance. On this basis, an enhanced NMS algorithm is proposed, which achieves a good balance between reducing false positives and missing detection. The experimental results verify the effectiveness of this method in pedestrian detection under occlusion.

关键词： pedestrian detection head detection head-aware pedestrian network affinity module occlusion

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Wear of semi-solid rheocast SiC_p/Al metal matrix composites

引用

中国有色金属学会会刊：英文版 2010年第S3期20卷 852-856页

作者： u.A.CuRlE l.IVANCHEV Materials Science and Manufacturing Council for Scientific and Industrial Research(South Africa)

Rheocasting of plates in Al alloy 359 reinforced with SiC at 11%,27% and 50%(volume fractions) exhibits the capability of the council for scientific and industrial research-rheocasting system(CSIR-RCS) in rheo-processing and high pressure die casting of SiC metal matrix *** metal matrix consisting of nearly spherical proeutectic α(Al) globules was *** of fibrous eutectic silicon took place upon heat treatment of the as-cast metal matrix composites(MMCs).Hardness increases as the volume fractions of SiC *** rates of the MMCs in the F and T6 heat treatment conditions were assessed with a metallographic preparation *** is found that the 11% SiC MMC wear rate is higher on SiC abrasives compared with the 50% SiC MMC wear rate due to wear of the aluminum *** trend is reversed on diamond abrasives due to pull-out of the irregular shaped composite *** 50% SiC MMC suffers from composite particle fracture porosity after high pressure die casting(HPDC).

关键词： CSIR-RCS HPDC SiC F condition T6 condition wear rate hardness porosity

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

On the detection of closed orbits in time-dependent systems by using double-pulse lasers

引用

Communications in Theoretical Physics 2020年第9期72卷 111-117页

作者： S u Khan M l Du Institute of Theoretical Physics Chinese Academy of Sciences.Beijing 100190China university of Chinese Academy of Sciences Beijing100049China

In the photodetachment of atoms or negative ions by a double-pulse laser, the first pulse of the double-pulse laser generates waves and the delayed second pulse may detect them. The phenomenon of the excitation and detection of waves by a double-pulse laser can be used to identify the closed orbits in the system. We demonstrate this phenomenon with a negative hydrogen ion(H^-) by analyzing the total population excited by a double-pulse laser in a timedependent field for different physical parameters. By analyzing the total excited population using a double-pulse laser, we can uncover all the closed orbits existing in the system. We demonstrate that this can be realized by scanning the first pulse position and the time delay between the two pulses.

关键词： double-pulse laser detection of closed orbits photodetachment spectra time-dependent systems

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effect of densification distribution on the Young's modulus of porous coatings after nano-indentation

引用

Acta Metal.urgica Sinica(English letters) 2012年第5期25卷 383-390页

作者： Xiaojuan l.u Ping XIAO Haiyan lI School of Environment Science and Engineering North China Electric Power University Yonghua North Street Baoding 071000 China School of Materials The University of Manchester Manchester M1 7HS UK School of Mechanical Aerospace and Civil Engineering The University of Manchester P.O. Box 88Sackville Street Manchester M60 1QD UK

Nano-indentation of a porous ceramic coating leads to crushing and densification of the coating under the indenter. In this work, finite element simulations of indentation on the porous coating have been carried out to study the effect of the size and dis- tribution of densification on Youngts modulus measured by nano-indentation. Two totally different distribution patterns have been simulated in this work. In the case of gradient densification, the Youngts modulus increased by 8.6% when the densifi- cation has occurred in the maximum influenced area. While the Young^s modulus increased by 2% with a uniformed densification. Examinations of the cross-section of the coatings have suggested that the densification after the indentation is close to the second model. The measured Young＇s modulus could have differed by 2%. The effect of densification on the Young＇s modulus measured by using nano-indentation is strongly dependent on the densification patterns of the porous coating.

关键词： Film Mechanical property Finite element simulation Porosity Electron Microscopy

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Dynamics of k-essence in loop quantum cosmology

引用

Chinese Physics C 2021年第4期45卷 451-461页

作者： jiali Shi Jian-Pin Wu College of Physical Science and Technology Bohai UniversityJinzhou 121013China Center for Gravitation and Cosmology College of Physical Science and TechnologyYangzhou UniversityYangzhou 225009China

In this paper,we study the dynamics of k-essence in loop quantum cosmology(lQC).The study indicates that the loop quantum gravity(lQG)effect plays a key role only in the early epoch of the universe and is diluted in the later *** fixed points in lQC are basically consistent with those in standard Friedmann-Robertson-Walker(FRW)*** most of the attractor solutions,the stability conditions in l Q C are in agreement with those for the standard FRW *** some special fixed points,however,tighter constraints are imposed thanks to the lQG effect.

关键词： k-essence loop quantum cosmology dynamics of dark energy

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

玉米秸秆生物炭电极用于微生物燃料电池脱硫反硝化性能

引用

环境工程学报 2024年第3期18卷 718-726页

作者：闫佳丽张铭川陈熙陈传杰徐新阳蒋绍妍东北大学资源与土木工程学院沈阳110819 辽宁生态工程职业学院林学院沈阳110101

研究了玉米秸秆生物炭作为微生物燃料电池电极的性能。阳极以S2-为单一电子供体,阴极以NO3-为电子受体,以碳毡为对照电极,考察玉米秸秆生物炭电极用于生物燃料电池同步脱硫反硝化的电化学性能、产电性能以及污染物去除能力,分析了不同... 详细信息

研究了玉米秸秆生物炭作为微生物燃料电池电极的性能。阳极以S2-为单一电子供体,阴极以NO3-为电子受体,以碳毡为对照电极,考察玉米秸秆生物炭电极用于生物燃料电池同步脱硫反硝化的电化学性能、产电性能以及污染物去除能力,分析了不同硫氮质量浓度比对生物炭电极微生物燃料电池脱氮除硫效率以及输出电能的影响。结果表明,玉米秸秆生物炭电极微生物燃料电池实现了更高的交换电流密度(22.42×10^(-3)A·cm^(-2))和更低的电荷转移电阻(4.24Ω)。与碳毡电极相比,玉米秸秆生物炭电极微生物燃料电池最大输出电压和最大功率密度分别提升了18.91%和16.67%。当硫氮比为5:4时,反应器脱硫反硝化和产电能力最佳。阳极室S2-出水质量浓度由120 mg·l^(-1)降至1.08 mg·l^(-1),去除率为99.1%,其中76.52%转化为SO_(4)^(2-)-S,阴极室NO_(3)^(-)-N去除率为94.5%。此时反应器输出电压和功率密度也达到最大值,分别为450.68 mV和1.03 W·m^(-2)。

关键词：微生物燃料电池生物炭脱硫反硝化电催化

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Surface Water Quality Profiling using Physicochemical Parameters in Open Defecation Free and Non-Open Defecation Free local Government Areas in Benue State, Nigeria

引用

Open Journal of Modern Hydrology 2024年第3期14卷 174-191页

作者： Moses T. Asoo Celestine u. Aguoru Innocent O. Ogbonna Hyacinth O.A. Oluma Benue State Ministry of Health Makurdi Nigeria Department of Plant Science and Biotechnology College of Biological Sciences Joseph Sarwuan Tarka University Makurdi Nigeria Department of Microbiology College of Biological Sciences Joseph Sarwuan Tarka University Makurdi Nigeria

Physicochemical parameters of surface water sources in the study of local government areas (lGAs) were assessed using standard procedures. The mean physicochemical parameters for pH (5.49), NO2 (0.23 mg/l), SO4 (0.77 mg/l), Na (28.72 mg/l), Ca (28.94 mg/l), Mg (17.50 mg/l), Cl (11.65 mg/l), TSS (6.27 mg/l), TDS (104.23 mg/l), BOD (2.83 mg/l) and F (0.87 mg/l) were below WHO standards irrespective of their defecation status. The values for electrical conductivity (EC) (2770.50 µs/cm, turbidity (481.24 NTu), dissolved oxygen (DO) (5.32 mg/l), chemical oxygen demand (COD) (445.50 mg/l), K (125.06 mg/l), PO4 (0.78 mg/l) and Fe (0.57 mg/l) were above the WHO limits for safe water. Higher EC and COD values obtained in the study is evidence of pol.ution of the water sources by organic matter.

关键词： Open Defecation Surface Water Water Quality Standard Physicochemical Parameters

来源：

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

发酵馕面团中优势菌群的分离及其在馒头发酵中的应用研究

引用

中国酿造 2024年第3期43卷 136-144页

作者：张甜刘艳全丁真真郁佳丽王继莲喀什大学生命与地理科学学院新疆喀什844000 新疆帕米尔高原生物资源与生态重点实验室新疆喀什844000

对新疆地区3份发酵馕面团样品中微生物进行分离、纯化,通过形态观察及分子生物学技术对分离菌株进行鉴定,并通过测定乳酸菌的产酸和酵母菌的产气能力,筛选优良菌株用于发酵馒头的制备,分析其对馒头感官品质及风味物质的影响。结果表明,... 详细信息

对新疆地区3份发酵馕面团样品中微生物进行分离、纯化,通过形态观察及分子生物学技术对分离菌株进行鉴定,并通过测定乳酸菌的产酸和酵母菌的产气能力,筛选优良菌株用于发酵馒头的制备,分析其对馒头感官品质及风味物质的影响。结果表明,分离纯化得到36株乳酸菌和51株酵母菌,乳酸菌包括旧金山乳杆菌(lactobacil.us sanfranciscensis)、植物乳杆菌(lactobacil.us plantarum)、发酵乳杆菌(lactobacil.us fermentum)和粪肠球菌(Enterococcus faecalis)4种;酵母菌包括发酵毕赤酵母(Pichia fermentans)、酿酒酵母(Saccharomyces cerevisiae)和膜毕赤酵母(Pichia membranifaciens)3种。植物乳杆菌产酸量最大,为113.55~127.8 g/l;酿酒酵母和发酵毕赤酵母产气较快。发酵毕赤酵母与安琪酵母单独发酵馒头时,在醇类和酯类物质的种类和相对含量上差异较大,风味差异明显;植物乳杆菌与发酵毕赤酵母菌混菌发酵馒头时,随着发酵毕赤酵母添加量增加,可降低馒头中醇类、醛类和烃类物质的相对含量,增加酮类和酯类物质的相对含量,从而形成不同于安琪酵母发酵馒头的风味;当添加比例为1∶2时,馒头感官评分最高(87分)。

关键词：发酵馕面团乳酸菌酵母菌分离纯化鉴定馒头风味物质

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

SiCp/Al复合材料在常规与超声振动辅助条件的切削过程和表面形成的有限元分析

引用

制造技术与机床 2024年第4期 51-56页

作者：马国红张加力闫帆施訸曦刘莉太原科技大学机械工程学院山西太原030024 山西黄河呼延建设工程有限公司山西太原030023

SiCp/Al复合材料是一种典型的难加工的材料,由于其基体中颗粒增强导致常规切削中加工质量差、切削阻力高、加工损伤高,机械加工性差,常规切削已不能满足加工要求。通过切削仿真,对比分析常规与超声振动辅助切削条件下复合材料的切削过程... 详细信息

SiCp/Al复合材料是一种典型的难加工的材料,由于其基体中颗粒增强导致常规切削中加工质量差、切削阻力高、加工损伤高,机械加工性差,常规切削已不能满足加工要求。通过切削仿真,对比分析常规与超声振动辅助切削条件下复合材料的切削过程、SiC颗粒的损伤特性、工件的表面形貌与亚表面损伤。结果表明,相比于常规切削,超声振动辅助切削可以提高复合材料的表面完整性,减少复合材料的亚表面损伤,并且能够提高工件的表面质量。

关键词： SiCp/Al复合材料有限元模拟超声振动辅助切削切削机理表面质量

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：