检索结果-南通市图书馆

Long-term thinning decreases the contribution of heterotrophic respiration to soil respiration in subalpine plantations

引用

Journal of Forestry Research 2024年第3期35卷 189-204页

作者： Longfei Chen Zhibin He Wenzhi Zhao Xi Zhu Qin Shen Mingdan Song Zhengpeng Li Junqia Kong Shuping Yang Yuan Gao Northwest Institute of Eco-Environment and Resources Chinese Academy of SciencesLanzhou 730000People's Republic of China State Forestry Administration Key Laboratory of Forest Resources and Environmental Management Beijing Forestry UniversityBeijing 100083People's Republic of China Academy of Agriculture and Forestry sciences Qinghai UniversityXining 810000People's Republic of China College of Landscape Architecture Zhejiang A&F UniversityHangzhou 310000People's Republic of China

Interest in the dynamics of soil respiration(R_(S))in subalpine forest ecosystems is increasing due to their high soil carbon density and potential sensitivity to environmental ***,as a principal silvicultural practice,the long-term impacts of thinning on R_(S) and its heterotrophic and autotrophic respiration components(R_(h) and Ra,respectively)in subalpine plantations are poorly understood,espe-cially in winter.A 3-year field observation was carried out with consideration of winter CO_(2) efflux in middle-aged sub-alpine spruce plantations in northwestern China.A trench-ing method was used to explore the long-term impacts of thinning on Rs,Rn and R_(a).Seventeen years after thinning,mean annual Rs,Rn and R_(a) increased,while the contribu-tion of R_(h) to R_(s) decreased with thinning *** significantly decreased winter R,because of the reduction in R_(n) but had no significant effect on *** temperature sensitivity(Q_(10))of R_(h) and R_(a) also increased with thinning intensity,with lower Q_(10) values for R_(h)(2.1-2.6)than for Ra(2.4-2.8).The results revealed the explanatory variables and pathways related to R_(n) and R_(a) *** increased soil moisture and nitrate nitrogen(NO_(3)^(-)-N),and the enhanced nitrogen and water availability promoted R_(h) and R_(a) by improving fine root biomass and microbial *** results highlight the positive roles of NO_(3)^(-)-N in stimulating R_(s) components following long-term ***,applications of nitrogen fertilizer are not recommended while thinning subalpine spruce plantations from the perspective of reducing soil CO_(2) *** increased Q_(10) values of R_(s) components indicate that a large increase in soil CO_(2) emissions would be expected following thinning because of more pronounced climate warming in alpineregions.

关键词： Heterotrophic respiration Autotrophic respiration Long-term thinning impacts Cold seasons Subalpine plantations Temperature sensitivity

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

Regulation effects of water and nitrogen on yield,water,and nitrogen use efficiency of wolfberry

引用

Journal of Arid Land 2024年第1期16卷 29-45页

作者： GAO Yalin QI Guangping MA Yanlin YIN Minhua WANG Jinghai WANG Chen TIAN Rongrong XIAO Feng LU Qiang WANG Jianjun College of Water Conservancy and Hydropower Engineering Gansu Agricultural UniversityLanzhou 730070China Jingtaichuan Electric Power Irrigation Water Resource Utilization Center in gansu Province Baiyin 730900China

Wolfberry(Lycium barbarum L.)is important for health care and ecological ***,it faces problems of low productivity and resource utilization during *** reasonable models for water and nitrogen management is important for solving these *** on field trials in 2021 and 2022,this study analyzed the effects of controlling soil water and nitrogen application levels on wolfberry height,stem diameter,crown width,yield,and water(WUE)and nitrogen use efficiency(NUE).The upper and lower limits of soil water were controlled by the percentage of soil water content to field water capacity(θ_(f)),and four water levels,i.e.,adequate irrigation(W0,75%-85%θ_(f)),mild water deficit(W1,65%-75%θ_(f)),moderate water deficit(W2,55%-65%θ_(f)),and severe water deficit(W3,45%-55%θ_(f))were used,and three nitrogen application levels,i.e.,no nitrogen(N0,0 kg/hm^(2)),low nitrogen(N1,150 kg/hm^(2)),medium nitrogen(N2,300 kg/hm^(2)),and high nitrogen(N3,450 kg/hm^(2))were *** results showed that irrigation and nitrogen application significantly affected plant height,stem diameter,and crown width of wolfberry at different growth stages(P<0.01),and their maximum values were observed in W1N2,W0N2,and W1N3 *** weight per plant and yield of wolfberry first increased and then decreased with increasing nitrogen application under the same water *** weight per hundred grains and dry weight percentage increased with increasing nitrogen application under W0 ***,under other water treatments,the values first increased and then decreased with increasing nitrogen *** and its component of wolfberry first increased and then decreased as water deficit increased under the same nitrogen *** water use efficiency(IWUE,8.46 kg/(hm^(2)·mm)),WUE(6.83 kg/(hm^(2)·mm)),partial factor productivity of nitrogen(PFPN,2.56 kg/kg),and NUE(14.29 kg/kg)reached their highest values in W2N2,W1N2,W1N2,and W1N1 treatments.R

关键词： water deficit growth characteristics yield water and nitrogen use efficiency principal component analysis

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

Precisely Control Relationship between Sulfur Vacancy and H Absorption for Boosting Hydrogen Evolution Reaction

引用

Nano-Micro Letters 2024年第4期16卷 14-24页

作者： Jing Jin Xinyao Wang Yang Hu Zhuang Zhang Hongbo Liu Jie Yin Pinxian Xi College of Chemistry and Chemical Engineering Frontiers Science Center for Rare IsotopesState Key Laboratory of Applied Organic ChemistryLanzhou UniversityLanzhou 730000People’s Republic of China

Ef fective and robust catalyst is the core of water splitting to produce ***, we report an anionic etching method to tailor the sulfur vacancy(VS) of NiS_(2) to further enhance the electrocatalytic performance for hydrogen evolution reaction(HER). With the VS concentration change from 2.4% to 8.5%, the H* adsorption strength on S sites changed and NiS_(2)-VS 5.9% shows the most optimized H* adsorption for HER with an ultralow onset potential(68 m V) and has long-term stability for 100 h in 1 M KOH media. In situ attenuated-total-reflection Fourier transform infrared spectroscopy(ATR-FTIRS) measurements are usually used to monitor the adsorption of intermediates. The S-H* peak of the Ni S_(2)-VS 5.9% appears at a very low voltage, which is favorable for the HER in alkaline media. Density functional theory calculations also demonstrate the Ni S_(2)-VS 5.9% has the optimal |ΔG^(H*)| of 0.17 e V. This work offers a simple and promising pathway to enhance catalytic activity via precise vacancies strategy.

关键词： Hydrogen evolution reaction S vacancies Nanosheet H Adsorption

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

Cotton leaf disease detection method based on improved SSD

引用

International Journal of Agricultural and Biological Engineering 2024年第2期17卷 211-220页

作者： Wenjuan Guo Shuo Feng Quan Feng Xiangzhou Li Xueze Gao College of Mechanical and Electrical Engineering Gansu Agricultural UniversityLanzhou 730070China School of Cyber Security Gansu University of Political Science and LawLanzhou 730070China College of Mechanical and Electrical Engineering Sichuan Agricultural UniversityYa’an 625014China

In response to the problems of numerous model parameters and low detection accuracy in SSD-based cotton leaf disease detection methods,a cotton leaf disease detection method based on improved SSD was proposed by combining the characteristics of cotton leaf ***,the lightweight network MobileNetV2 was introduced to improve the backbone feature extraction network,which provides more abundant semantic information and details while significantly reducing the amount of model parameters and computing complexity,and accelerates the detection speed to achieve real-time ***,the SE attention mechanism,ECA attention mechanism,and CBAM attention mechanism were fused to filter out disease target features and effectively suppress the feature information of jamming targets,generating feature maps with strong semantics and precise location *** test results on the self-built cotton leaf disease dataset show that the parameter quantity of the SSD_MobileNetV2 model with backbone network of MobileNetV2 was 50.9%of the SSD_VGG model taking VGG as the *** with SSD_VGG model,the P,R,F1 values,and mAP of the MobileNetV2 model increased by 4.37%,3.3%,3.8%,and 8.79%respectively,while FPS increased by 22.5 frames/*** SE,ECA,and CBAM attention mechanisms were introduced into the SSD_VGG model and SSD_MobileNetV2 *** gradient weighted class activation mapping algorithm to explain the model detection process and visually compare the detection results of each *** results indicate that the P,R,F1 values,mAP and FPS of the SSD_MobileNetV2+ECA model were higher than other models that introduced the attention ***,this model has less parameter with faster running speed,and is more suitable for detecting cotton diseases in complex environments,showing the best detection ***,the improved SSD_MobileNetV2+ECA model significantly enhanced the semantic information of the shallow feature map of the model,and has a goo

关键词： cotton disease detection SSD MobileNetV2 attention mechanism

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

Thermal Property Enhancement of a Novel Shape-Stabilized Sodium Acetate Trihydrate-Acetamide/Expanded Graphite-Based Composite Phase Change Material

引用

Journal of Thermal science 2024年第4期33卷 1564-1576页

作者： AN Zhoujian HOU Wenjie DU Xiaoze HUANG Zhongzheng MOMBEKI PEA Hamir Johan ZHANG Dong LIU Xiaomin College of Energy and Power Engineering Lanzhou University of TechnologyLanzhou730050China Key Laboratory of Multi-supply System with Solar Energy and Biomass of gansu Province Lanzhou730050China gansu Natural Energy Research Institute Lanzhou730046China

Phase change materials(PCMs)are a kind of highly efficient thermal storage materials which have a bright application prospect in many fields such as energy conservation in buildings,waste heat recovery,battery thermal management and so *** inorganic hydrated salt PCMs have received increasing attention from researchers due to their advantages of being inexpensive and ***,inorganic hydrated salt PCMs are still limited by the aspects of inappropriate phase change temperature,liquid phase leakage,large supercooling and severe phase separation in the application *** this work,sodium acetate trihydrate was selected as the basic inorganic PCM,and a novel shape-stabilized composite phase change material(CPCM)with good thermal properties was prepared by adding various functional *** first,the sodium acetate trihydrate-acetamide binary mixture was prepared and the melting point was adjusted using *** the binary mixture was incorporated into expanded graphite to synthesize a novel shape-stabilized *** thermophysical properties of the resultant shape-stabilized CPCM were systematically *** microscopic morphology and chemical structure of the obtained shape-stabilized CPCM were characterized and *** experiment results pointed out that acetamide could effectively lower the melting point of sodium acetate *** obtained shape-stabilized CPCM modified with additional 18%(mass fraction)acetamide and 12%(mass fraction)expanded graphite exhibited good shape stability and thermophysical characteristics:a low supercooling degree of 1.75℃and an appropriate melting temperature of 40.77℃were obtained;the latent heat of 151.64 kJ/kg and thermal conductivity of 1.411 W/(m·K)were also ***,after 50accelerated melting-freezing cycles,the obtained shape-stabilized CPCM represented good thermal reliability.

关键词： sodium acetate trihydrate melting point modification agent expanded graphite shape stability thermal conductivity enhancement

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

磁性复合流体对砷化镓晶片的超精密表面抛光

引用

稀有金属材料与工程 2024年第2期53卷 377-385页

作者：王有良梁博张文娟兰州理工大学机电工程学院甘肃兰州730050 兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室甘肃兰州730050

研究了磁性复合流体(MCF)浆料对砷化镓(Ga As)晶片表面纳米精密抛光的影响。通过混合CS羰基铁颗粒(CIPs)、Al_(2)O_(3)磨料颗粒、α-纤维素和磁性流体制备MCF浆料。首先,通过设计用于产生旋转磁场的MCF单元,建立了抛光装置。然后,对Ga A... 详细信息

研究了磁性复合流体(MCF)浆料对砷化镓(Ga As)晶片表面纳米精密抛光的影响。通过混合CS羰基铁颗粒(CIPs)、Al_(2)O_(3)磨料颗粒、α-纤维素和磁性流体制备MCF浆料。首先,通过设计用于产生旋转磁场的MCF单元,建立了抛光装置。然后,对Ga As晶片表面进行了点抛光实验,以阐明MCF成分对不同抛光位置的表面粗糙度R_(a)和材料去除(MR)的影响。最后,使用含有不同直径颗粒的水基MCF浆料进行了扫描抛光实验。结果表明,在点抛光的情况下,水基和油基MCF处理后的初始表面粗糙度从954.07 nm分别降至1.02和20.06 nm。此外,MR的深度随着抛光时间的增加而线性增加。使用水基MCF的MR深度是使用油基MCF抛光的2.5倍。同时,抛光区的横截面轮廓显示出W型,这表明点抛光工件表面的MR不均匀。通过扫描抛光,抛光区的横截面轮廓显示出U型,这表明在给定的实验条件下,无论使用何种MCF,MR都是均匀的。使用含有直径为0.3μm的磨粒的MCF能够获得R_(a)为0.82 nm的最光滑工作表面,同时MR速率为13.5μm/h。

关键词：磁性复合流体砷化镓晶片抛光表面粗糙度材料去除

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

A VNS-NPGA Approach to Multi-Objective Optimization of Hub-and-spoke Logistics Network

引用

Journal of Traffic and Transportation Engineering(English Edition) 2024年

作者： Changxi Ma Chuwei Shi Yun Yang Yongpeng Zhao Zhuye Xu Bo Du School of Traffic and Transportation Lanzhou Jiaotong University Key Laboratory of Railway lndustry on Plateau Railway Transportation Intelligent Management and Control Lanzhou Jiaotong University School of Tourism and Management Yangling Vocational and Technical College School of New Energy and Power Engineering Lanzhou Jiaotong University National Engineering Research Center of Highway Maintenance technology Changsha University of science & technology SMART Infrastructure Facility University of Wollongong

To realize low-cost freight transport in the logistics network and improve the network operation efficiency， a multi-objective optimization model and the corresponding algorithm for a hub-and-spoke logistics network are proposed based on the multi-level location of hub points and channels layout. By considering the structure of the multi-level hub-and-spoke logistics network and the features of the connectivity between the hub and spoke points， the multi-objective optimization model is constructed with two objectives of minimizing the total network operation costs and the total network service time. By considering the characteristics of decision variables and models， a Variable Neighborhood Search (VNS)-Niched Pareto Genetic Algorithm (NPGA) approach with a three-stage encoding structure chromosome is proposed， where the VNS algorithm nested in NPGA is used for individual variable neighborhood search to optimize individual channel level genes， and NPGA is adopted to solve the multi-objective optimization model. To evaluate the performance of the proposed VNS-NPGA approach， a real-life case study based on a small-scale Australia Post data set was conducted， and 25 nodes of the Australia Post and 14 nodes of the gansu Province 3-level hub-and-spoke logistics networks were established， respectively. The analysis results indicated that the network structure of multi-level hub points could avoid the detour problem existing in the traditional hub-and-spoke network， and showed better applicability in the narrow geographical structure. Compared to the traditional multi-objective evolutionary algorithms， VNS-NPGA can obtain better solutions through the distributed optimization of channel levels， avoiding the problem that a single algorithm cannot effectively deal with coupling relationships in genes.

关键词：

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

Research Progress of Acupuncture Treatment of Neurogenic Bladder after Spinal Cord Injury

引用

Journal of Clinical and Nursing Research 2024年第4期8卷 297-302页

作者： Chunxuan Dong Qibin Sun Guodong Chen Xiumei Xu Xiaoju Zhang Decheng Gan gansu Provincial Hospital of Traditional Chinese Medicine Lanzhou 73000Gansu ProvinceChina

Neurogenic bladder (NB) mainly occurs in patients with spinal cord injury (SCI). The pathological basis of NB is the occurrence of lesions in the urination control center, which requires systematic treatment. Western medicine has many treatment methods for this disease, which can alleviate the symptoms of the disease. However, the radical effect is not ideal and there are many adverse reactions. In comparison, acupuncture can improve the residual urine volume of NB patients and regulate the related indexes of urodynamics. There are many kinds of acupuncture therapies, such as simple acupuncture and moxibustion, which can comprehensively improve the therapeutic effect and obtain a better disease prognosis. Therefore, this article elaborates on the pathogenesis of SCI complicated with NB, the treatment mechanism, and treatment methods of acupuncture and moxibustion to provide a reference for clinical treatment.

关键词： Acupuncture Spinal cord injury Neurogenic bladder

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

Hot subduction in the southern Paleo-Asian Ocean:Insights from clinopyroxene chemistry and Sr-Nd-Hf-Pb isotopes of Carboniferous volcanics in West Junggar

引用

Geoscience Frontiers 2024年第1期15卷 155-174页

作者： Yao Xiao Xijun Liu Wenjiao Xiao Xiao-Han Gong Hao Wu Yujia Song Zhiguo Zhang Pengde Liu Guangxi Key Laboratory of Hidden Metallic Ore Deposits Exploration College of Earth SciencesGuilin University of TechnologyGuilin 541004China Collaborative Innovation Center for Exploration of Nonferrous Metal Deposits and Efficient Utilization of Resource Guilin University of technology Guilin 541004China National Key Laboratory of Ecological Security and Resource Utilization in Arid Areas Xinjiang Institute of Ecology and GeographyChinese Academy of SciencesUrumqi 830011China School of Earth sciences and Resources China University of GeosciencesBeijing 100083China College of Civil Engineering Hexi UniversityZhangye 734000China

The chemical evolution and pressure-temperature conditions of subduction zone magmatism along ancient suture zones in orogenic belts can provide important information regarding plate convergence processes in *** magmatism in West Junggar is key to understanding the tectonothermal and subduction history of the Junggar Ocean,which was a branch of the Paleo-Asian Ocean,as well as the accretionary processes in the southwestern Central Asian Orogenic Belt(CAOB).We undertook a geochronological,mineralogical,geochemical,and Sr-Nd-Hf-Pb isotopic study of volcanic rocks from the Baikouquan area of West *** used these data to determine the petrogenesis,mantle source,and pressure-temperature conditions of these magmas,and further constrain the subduction and tectonic history of the Junggar *** studied volcanic rocks yielded zircon U-Pb ages of 342-337 Ma and are characterized by enrichments of large-ion lithophile elements(LILEs),and depletions in high-field-strength elements(HFSEs),indicative of an island arc *** volcanic rocks have positiveƐNd(t)(5.83-7.04)andƐHf(t)(13.47-15.74)values,87Sr/86Sr(t)ratios of 0.704023-0.705658,and radiogenic 207Pb/204Pb(t)and 208Pb/204Pb(t)ratios at a given 206Pb/204Pb(t)ratio,indicative of a depleted mantle source contaminated by subduction-related *** modeling calculations indicate that≤1%of a subduction component comprising fluid and sediment melt could have generated the source of the parental melts of the Baikouquan volcanic *** phenocrysts in the volcanic rocks are classified as high-and low-Ti clinopyroxene,and pressure-temperature calculations suggest the host rocks formed at high temperatures(~1300℃)and shallow to moderate depths(<2 GPa).The magma was probably generated by hot and hydrous melting in a mantle wedge in response to subduction of young,hot oceanic *** present results,combined with published data,suggest that the Baikouquan volcanic r

关键词： Hot subduction Sr-Nd-Hf-Pb isotopes Clinopyroxene chemistry West Junggar Central Asian Orogenic Belt

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

Wireless remote spatiotemporal monitoring of high-fill foundation deformation

引用

Journal of Mountain science 2023年第6期20卷 1620-1638页

作者： YANG Xiao-hui LI Zhi-qian ZHU Yan-peng GUO Nan School of Civil Engineering Lanzhou University of TechnologyLanzhou 730050China Western Engineering Research Center of Disaster Mitigation in Civil Engineering of Ministry of Education Lanzhou University of TechnologyLanzhou 730050China

The spatial and temporal deformation patterns and deformation control indicators of highfill foundations directly affect the design,construction and operational safety of high-fill *** situ monitoring can comprehensively reflect the deformation of high-fill during and after *** this paper,we have first designed and installed an integrated wireless remote monitoring system for high-fill to achieve real-time dynamic monitoring of settlement,pore water pressure and soil pressure of the fill *** on the monitoring results of nearly one year of the construction period and two years after construction,it was found that the deformation amount and deformation rate of the high-fill foundation showed a non-linear growth relationship with the filling rate and filling *** settlement deformation of the high-fill foundation during the loading period was mainly dominated by the original foundation soil,accounting for 54.4%of the total settlement on average;the settlement deformation during the post-construction period was mainly dominated by the filling body,accounting for 77.04%of the total settlement on average,and the settlement deformation during the post-construction period mainly occurred in the first year after *** analysis of the deformation mechanism suggests that the deformation of the filling body is dominated by exhaust consolidation during the loading period and drainage consolidation during the post-construction period;the deformation of the original foundation soil is dominated by drainage consolidation during the loading period and drainage consolidation develops slowly during the post-construction *** is recommended that the original foundation should be reinforced before the large area filling construction,and that the filling rate should be strictly controlled during *** research results can provide a scientific basis for deformation calculation and stability assessment of high-fill foundatio

关键词： High-fill engineering Wireless remote monitoring Foundation deformation Spatiotemporal law Settlement after construction

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：