检索结果-南通市图书馆

A dopant-assisted iodide-adduct chemical ionization time-of-flight mass spectrometer based on VUV lamp photoionization for atmospheric low-molecular-weight organic acids analysis

引用

Journal of Environmental Sciences 2025年第3期149卷 500-511页

作者： Yonglei Zhang Ruidong Liu Mei Li Yingzhe Guo Jichuang Kong Keyong Hou Environment research institute Shandong UniversityQingdao 266237China

Formic and acetic acids are the most abundant gaseous organic acids and play the key role in the atmospheric *** iodine-adduct chemical ionizationmass spectrometry(CIMS),the low utilization efficiency of methyl iodide and humidity interference are two major issues of the vacuum ultraviolet(VUV)lamp initiated CIMS for on-line gaseous formic and acetic acids *** this work,we present a new CIMS based on VUV lamp,and the ion-molecular reactor is separated into photoionization and chemical ionization zones by a reducer *** was added to the photoionization zone,and the VUV photoionization acetone provided low-energy electrons for methyl iodide to generate I−,and the addition of acetone reduced the amount of methyl iodide by 2/*** the chemical ionization zone,a headspace vial containing ultrapure water was added for humidity calibration,and the vial changes the sensitivity as a function of humidity from ambiguity to well linear correlation(R2>0.95).With humidity calibration,the CIMS can quantitatively measure formic and acetic acids in the humidity range of 0%-88%*** this mode,limits of detection of 10 and 50 pptv are obtained for formic and acetic acids,*** the relative standard deviation(RSD)of quantitation stability for 6 days were less than 10.5%.This CIMS was successfully used to determine the formic and acetic acids in the underground parking and ambient environment of the Shandong University campus(Qingdao,China).In addition,we developed a simple model based formic acid concentration to assess vehicular emissions.

关键词： Formic acid Acetic acid Vacuum ultraviolet(VUV)lamp photoionization(PI) Chemical ionization(CI) Time-of-flight mass spectrometry (TOFMS) Trace gases measurement

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

Modulated waveforms for harmonic minimization of far-field signals in amplitude-modulated heating of the ionosphere

引用

Earth and Planetary Physics 2025年第02期9卷 387-399页

作者： ZhiJian Lu Yong Li Hui Li Jian Wu JingFeng Yao XingBao Lyu ChengXun Yuan ZhongXiang Zhou Ying Wang School of Physics Harbin Institute of Technology China research institute of radio Waves Propagation Heilongjiang Provincial Key Laboratory of Plasma Physics and Application Technology Heilongjiang Provincial Innovation research Center for Plasma Physics and Application Technology (International Cooperation)

This paper establishes an amplitude modulation heating model, simulating the far-field radiation of ELF/VLF signals generated by modulation heating, as well as the specific location and longitudinal extent of the radiation source. We consider various modulation waveforms and find that square-wave modulation has the highest excitation efficiency for ELF/VLF signals, and that square-wave modulation with a smaller duty cycle(<50%) exhibits higher excitation efficiency for ELF/VLF signals, while the sin2t waveform modulation yields the lowest proportion of harmonic energy in the generated signals. The amplitude of the second harmonic generated by the sin2t waveform is less than one-tenth that of the fundamental frequency, and the energy of higher-frequency harmonics can be negligibly small compared with those of the fundamental wave. It is a challenging task to achieve a balance between enhancing the excitation efficiency of ELF/VLF signals and also suppressing harmonics generated by the modulated heating process. This is because the harmonics are correspondingly enhanced as the excitation efficiency of the signals is increased. However, we find that under conditions of varying effective radiant power and modulation frequency, as long as the modulation waveform is unchanged, the energy ratio between the fundamental frequency signal generated by modulated heating and each harmonic is relatively fixed, with changes only in signal intensity and the location of the radiation source zone. This implies that one can first select modulation waveforms that make the signal less prone to distortion, then increase the effective radiated power to enhance the signal strength, without concern for harmonic interference of the fundamental signal.

关键词： ELF/VLF harmonic amplitude-modulated heating modulated waveforms

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

Design and Application of Turbine Cascade Partitioned Endwall Profiling

引用

Journal of Thermal Science 2025年第1期34卷 110-128页

作者： ZENG Fei JIANG Ruiqi XUE Xingxu DU Wei LUO Lei ZHOU Xun AECC Hunan Aviation Powerplant research institute Zhuzhou 412002China School of Energy Science and Technology Harbin Institute of TechnologyHarbin 150001China Science and Technology on Diesel Engine Turbocharging Laboratory China North Engine Research InstituteTianjin 300270China

The influence of partitioned profiling design based on a large-pitch highly loaded cascade is studied by numerical *** partitioned profile is mainly composed of a pressure-side convex structure near the leading edge and a suction-side convex structure at the midstream and downstream sides of the *** influence of the change in the vertex axial position and peak value of the B-line on the secondary flow control is *** this paper,air(ideal gas)is selected as the flow *** average static pressure at the outlet and the average total temperature at the inlet are kept *** γ-θ is used as the turbulence *** results show that the pressure-side convex structure suppresses the spanwise and pitchwise migration of the inlet flow by adjusting the static pressure distribution of the flow field,so the development of the pressure-side leg of the horseshoe vortex is effectively *** suction-side convex structure adjusts the static pressure distribution of the flow field and increases the included angle between the cross-flow and suction surface,so the accumulation of low-momentum fluid,the development of a corner vortex and the flow separation at the trailing edge of the suction-side surface are all suppressed near the endwall-suction ***,the energy loss coefficient of the large-pitch highly loaded cascade is decreased from 0.0564 to 0.0485,representing a 25% reduction in secondary flow losses.

关键词： large-pitch highly loaded cascade highly loaded design non-axisymmetrical endwall design secondary flow control partitioned endwall profiling

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

Tackling the microlensing wave effects of strong lensing gravitational waves with TAAH

引用

Science China(Physics,Mechanics & Astronomy) 2025年第1期68卷 253-254页

作者： Zuhui Fan South-Western institute for Astronomy research Yunnan UniversityKunming 650500China

The rapid development of gravitational wave(GW) observations since their first detection in 2015 [1] has opened a completely new window for exploring the Universe. Consequently, astronomical research has entered the multimessenger era, allowing us to use different tracers to view the cosmos from various perspectives. Among others, the appealing application of gravitational wave events from compact binary mergers is that they can act as standard sirens to determine absolute cosmic distances entirely independent of standard candles. This approach is one of the most promising means to solve the current H0tension problem.

关键词： problem. app wave

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

Higher abundance of DLD protein in buffalobull spermatozoa causes elevated ROSproduction leading to early sperm capacitationand reduction in fertilizing ability

引用

Journal of Animal Science and Biotechnology 2025年第1期16卷 107-120页

作者： Seema Karanwal Ankit Pal Fanny Josan Aditya Patel Jatinder Singh Chera Sonam Yadav Vikrant Gaur Preeti Verma Shiva Badrhan Vitika Chauhan Mukesh Bhakat Tirtha Kumar Datta Rakesh Kumar Animal Genomics Laboratory Animal Biotechnology DivisionICAR-National Dairy Research InstituteKarnalHaryanaIndia NBGC Laboratory National Bureau of Animal Genetics ResourcesKarnalHaryanaIndia Artificial Breeding research Centre LPM DivisionICAR-National Dairy Research InstituteKarnalHaryanaIndia ICAR-Central institute of research On Goat MakhdoomMathuraUttar PradeshIndia ICAR-Central institute for research On Buffaloes HisarHaryanaIndia

Backgroud Before fertilization,spermatozoa undergo a crucial maturation step called capacitation,which is a unique event regulates the sperm’s ability for successful *** capacitation process takes place as the spermatozoa pass through the female reproductive tract(FRT).Dihydrolipoamide dehydrogenase(DLD)protein is a post-pyruvate metabolic enzyme,exhibiting reactive oxygen species(ROS)production which causes ***,other vital functions of DLD in buffalo spermatozoa are hyperactivation and acrosome *** produces the optimum amount of ROS required to induce capacitation process in *** on physiological or patho-physiological conditions,DLD can either enhance or attenuate the production of reactive oxygen species(ROS).Aim of this study was to investigate whether changes in the production of ROS in sperm cells can impact their ability to fertilize by triggering the capacitation and acrosome *** In this study,abundance of DLD protein was quantified between high(n=5)and low fertile bull(n=5)*** was found that compared to high-fertile(HF)bulls,low-fertile(LF)bulls exhibited significantly(P<0.05)higher DLD ***,we optimised the MICA concentration to inhibit DLD function,spermatozoa were treated with MICA in time(0,1,2,3,4,and 5 h)and concentrations(1,2.5,5,and 10 mmol/L)dependent *** DLD inhibition was found to be at 4 h in 10 mmol/L MICA concentration,which was used for further exper-imentation in HF and *** on DLD inhibition it was seen that LF bull spermatozoa exhibited significantly(P<0.05)higher ROS production and acrosome reaction in comparison to the HF bull *** kinematic parameters of the spermatozoa such as percent total motility,velocity parameters(VCL,VSL,and VAP)and other parameters(BCF,STR,and LIN)were also decreased in MICA treated spermatozoa in comparison to the control(capacitated)*** The present study provides an initial

关键词： Acrosome reaction Capacitation High fertile bull Low fertile bull Protein Reactive oxygen species Spermatozoa

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

Site-specific patterns of fine root biomass formation across European coniferous forests

引用

Forest Ecosystems 2025年第1期12卷 104-111页

作者： Yury Karpechko Anna Karpechko Andrej Tuyunen Forest research institute of the Karelian research Centre of the Russian Academy of Sciences 11 Pushkinskaya StPetrozavodskKarelia185910Russia

Fine roots play a crucial role in the biogeochemical cycles of terrestrial *** of fine roots biomass formation for broad geographical areas are still *** use published estimates of characteristics of European pine and spruce stands to determine their productivity and calculate the needle ***,the relationship between the fine-root:needle biomass ratio of European pine and spruce forests and the stand quality index,which is a proxy of soil fertility,was *** show that a rise in soil fertility is accompanied by a decrease in this *** from the northern edge of the boreal zone southwards,with the related rise in air and soil temperatures,we see a decline in the mass ratio of fine roots and *** change in the fine-root:needle biomass ratio is controlled by the change in specific water uptake by roots,which is related to the osmotic pressure of the solution in the absorbing root's central vascular *** fine-root:needle ratio does not vary among stands of the same age if the stand quality index and the geographical latitude(a proxy of air and soil temperatures)are *** findings may be useful for further in-depth analysis of forest ecosystem functioning in Europe.

关键词： Fine-root:needle biomass ratio Stand quality class Soil fertility Latitudinal variation Allometric equation

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

Managing virus diseases in citrus:Leveraging high-throughput sequencing for versatile applications

引用

Horticultural Plant Journal 2025年第1期11卷 57-68页

作者： Hongming Chen Zhiyou Xuan Lu Yang Song Zhang Mengji Cao Integrative Science Center of Germplasm Creation in Western China(Chongqing)Science City Citrus Research InstituteSouthwest UniversityChongqing 400712China National Citrus Engineering research Center Citrus Research InstituteSouthwest UniversityChongqing 400712China

In this review,the advantages and advances in applying high-throughput sequencing(HTS)in the management of viral diseases in citrus,along with some challenges,are discussed to provide perspectives on future *** the initial implementation of HTS in citrus virology,a substantial number of citrus viruses have been identified,with a notable increase in the last 7 *** acquisition of viral genomes and various HTS-based omics analyses serve as crucial pillars for advancing research in the etiology,epidemiology,pathology,evolution,ecology,and biotechnology of citrus *** has notably contributed to disease diagnosis,such as the diagnoses of concave gum and impietratura,as well as to the surveillance of new virus risks and the preparation of virus-free ***,certain inherent defects in HTS and coupled bioinformatics analysis,such as challenges with sequence assembly and the detection of viral dark matter,require improvement to enhance practical *** addition,the utilization of HTS for the systematic management of citrus viral diseases remains limited,and drawing insights from other virus-plant pathosystems while integrating emerging compatible techniques and ideas may broaden its specific applications.

关键词： Deep sequencing Virus epidemics Functional genomics CRISPR/Cas Virus-host interactions

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

Assessment of the heartwood contribution to carbon accumulation in Pinus sylvestris *** under different forest site conditions

引用

Forest Ecosystems 2025年第1期12卷 159-175页

作者： Natalia A.Galibina Kseniya M.Nikerova Sergey A.Moshnikov Alexander M.Kryshen Forest research institute of the Karelian research Centre of the Russian Academy of Sciences 11 Pushkinskaya St.185910PetrozavodskKareliaRussia

Background:The heartwood(HW)proportion in the trunk of mature trees is an important characteristic not only for wood quality but also for assessing the role of forests in carbon *** have for the first time studied the proportion of HW in the trunk and the distribution of carbon and extractives in sapwood(SW)and HW of 70–80 year old Pinus sylvestris *** under different growing conditions in the pine forests of North-West ***:We have examined the influence of conditions and tree position in stand(dominant,intermediate and suppressed trees)in the ecological series:blueberry pine forest(Blu)–lingonberry pine forest(Lin)–lichen pine forest(Lic).We have analyzed the influence of climate conditions in the biogeographical series of Lin:the middle taiga subzone–the northern taiga subzone–the transition area of the northern taiga subzone and ***:We found that the carbon concentration in HW was 1.6%–3.4%higher than in SW,and the difference depended on growing *** concentration in HW increased with a decrease in stand productivity(Blu-Lin-Lic).In medium-productive stands,the carbon concentration in SW was higher in intermediate and supressed trees compared to dominant *** the series from south to north,carbon concentration in HW increased by up to 2%,while in SW,it rose by 2.7%–3.8%.Conclusions:Our results once again emphasized the need for an empirical assessment of the accurate carbon content in aboveground wood biomass,including various forest growing conditions,to better understand the role of boreal forests in carbon storage.

关键词： Scots pine Blueberry pine forest Lingonberry pine forest Lichen pine forest Tree social class Climate Carbon content Extractives Cellulose Lignin

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

Detection in Optical Remote Sensing Images of Transmission Tower Based on Oriented Object Detection

引用

CSEE Journal of Power and Energy Systems 2025年第1期11卷 217-226页

作者： Yuanpeng Tan Fei Jiao Wenhao Mo Haiying Liu Xiaojing Bai Jiaxiu Ma China Electric Power research institute Beijing 100192China China Electric Power research institute and North China Electric Power University Beijing100192China China Electric Power research institute and State Grid Corporation of China Information and Communication Branch Beijing100192China

Transmission towers play a crucial role in overhead transmission line systems and are the key target of transmission line *** the help of remote sensing technology,transmission towers can be effectively detected in wide areas at reasonable costs and in a relatively short time ***,it is difficult to identify the type of transmission towers in optical remote sensing images due to detail degradation caused by long-distance and high-altitude *** paper proposes a transmission tower detection method in optical remote sensing images using an oriented object detector and object and shadow joint *** enrich the information,the transmission towers and their shadows are jointly detected through a CenterNet detector with an orientation prediction *** improve the detection accuracy of difficult objects,attention and deformable convolutional network modules are introduced to the backbone and orientation prediction branches,*** the orientation and the aspect ratio of the objects and shadows,a focal loss function with an aspect ratio is employed to further improve the *** and shadow joint detection are separately realized through the one-box and multi-box detection strategies.A transmission tower dataset RSITT labeled with horizontal and oriented boxes is *** conducted on the RSITT dataset have demonstrated that the detection accuracy and recall rate of the proposed joint detection algorithm reached 73.2%and 95.2%.

关键词： Oriented object detection remote sensing image transmission projection transmission tower detection

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

Fabrication and fracture behaviors of the continuous brittle fiber reinforced tungsten composites fabricated via field-assisted sintering technology

引用

Tungsten 2025年第1期7卷 172-182页

作者： Rui Shu Yi-Ran Mao Jan W. Coenen Alexis Terra Stephan Sch?nen Johann Riesch Christian Linsmeier Christoph Broeckmann Juelich research Center Institute of Energy and Climate Research Plasma Physics (IEK-4) Partner in the Trilateral Euregio Cluster institute of Materials Applications in Mechanical Engineering (IWM) RWTH Aachen University Department of Nuclear Engineering & Engineering Physics University of Wisconsin Madison Central institute of Engineering Electronics and Analytics Engineering and Technology (ZEA-1) Juelich Research Center Max Planck institute for Plasma Physics institute of Materials Applications in Mechanical Engineering IWM RWTH Aachen University

Tungsten（W） is a promising candidate material for the plasma-facing components in future fusion ***,it has issues regarding the intrinsic brittleness as well as operational *** fiber reinforced tungsten（W_f/W） composites overcome these issues by using extrinsic toughening *** to neutron irradiation and high-temperature recrystallization during fusion operation,the ductility of the fibers may degrade over a long period of ***,it is necessary to investigate the fracture behavior of W_f/W composites with brittle *** the present work,the tungsten fibers were embrittled by ***,the continuous brittle W_f/W composite with yttrium oxide（Y2O3） interface was fabricated by the field-assisted sintering technology *** microstructure of the prepared W_f/W composites was *** fracture behavior and toughening mechanisms were discussed in detail based on the experimental results of 3-point bending tests and the corresponding finite element *** composites show a pseudo-ductile fracture *** are hindered and deflected by the de-bonded fiber-matrix *** extrinsic toughening mechanisms of interface de-bonding,crack bridging,and fiber pull-out are *** indicates the reinforcement concept still works even though all components in the W_f/W are brittle.

关键词： Field-assisted sintering technology (FAST) Fracture behavior Interface Numerical simulation Wf/W composites

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

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：