检索结果-南通市图书馆

A Modified Helmholtz Equation with Impedance Boundary Conditions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Applied Mathematics and Mechanics 2012年第6期4卷 703-718页

作者： Robert S.Callihan aihua w.wood Air Force Institute of Technology 2950 Hobson WayWright-Patterson AFBOH 45433USA

Here considered is the problem of transient electromagnetic scattering from overfilled cavities embedded in an impedance ground *** artificial boundary condition is introduced on a semicircle enclosing the cavity that couples the fields from the infinite exterior domain to those fields inside.A Green’s function solution is obtained for the exterior domain,while the interior problem is solved using finite element ***-posedness of the associated variational formulation is achieved and convergence and stability of the numerical scheme *** experiments show the accuracy and robustness of the method.

关键词： Helmholtz equation impedance boundary conditions finite element method

A Hybrid Finite Element-Laplace Transform Method for the Analysis of Transient Electromagnetic Scattering by an Over-Filled Cavity in the Ground Plane

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2009年第1期5卷 126-141页

作者： Junqi Huang aihua w.wood Michael J.Havrilla Air Force Institute of Technology 2950 Hobson WayWright-Patterson AFBOH 45433USA

A hybrid finite element-Laplace transform method is implemented to analyze the time domain electromagnetic scattering induced by a 2-D overfilled cavity embedded in the infinite ground *** algorithm divides the whole scattering domain into two,interior and exterior,*** the interior sub-domain which covers the cavity,the problem is solved via the finite element *** problem is solved analytically in the exterior sub-domain which slightly overlaps the interior subdomain and extends to the rest of the upper half *** use of the Laplace transform leads to an analytical link condition between the overlapping *** analytical link guides the selection of the overlapping zone and eliminates the need to use the conventional Schwartz *** dramatically improves the efficiency for solving transient scattering *** solutions are tested favorably against analytical ones for a canonical *** perfect link over the artificial boundary between the finite element approximation in the interior and analytical solution in the exterior further indicates the reliability of the *** error analysis is also performed.

关键词： Overfilled cavity time domain electromagnetic scattering Laplace transform finite element method

Elevational patterns of warming effects on plant community and topsoil properties: focus on subalpine meadows ecosystem

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Mountain Science 2024年第1期21卷 146-159页

作者： HAO aihua LUO Zhengming CHEN Xiaojiang Department of Geography Xinzhou Normal UniversityXinzhou 034000China Department of Biological Sciences Xinzhou Normal UniversityXinzhou 034000China

Climate warming profoundly affects plant biodiversity, community productivity, and soil properties in alpine and subalpine grassland ecosystems. However, these effects are poorly understood across elevational gradients in subalpine meadow ecosystems. To reveal the elevational patterns of warming effects on plant biodiversity, community structure, productivity, and soil properties, we conducted a warming experiment using open-top chambers from August 2019 to August 2022 at high(2764 m a. s. l.), medium(2631 m a. s. l.), and low(2544 m a. s. l.) elevational gradients on a subalpine meadow slope of Mount wutai, Northern China. Our results showed that three years of warming significantly increased topsoil temperature but significantly decreased topsoil moisture at all elevations(Pwith elevation lifting. warming-induced decreasing proportions of soil organic carbon(SOC, by 19.24%), and total nitrogen(TN, by 24.56%) were the greatest at high elevational gradients. Experimental warming did not affect topsoil C: N, p H, NO_(3)^(-)-N, or NH_(4)^(+)-N at the three elevational gradients. warming significantly increased species richness(Pweiner index(Pw elevational gradients but significantly decreased belowground biomass(Pwarming caused significant increases in the aboveground biomass in the three elevational plots. warming significantly increased the aboveground biomass of graminoids in medium(by 92.47%) and low(by 98.25%) elevational gradients, that of sedges in high(by 72.44%) and medium(by 57.16%) elevational plots, and that of forbs in high(by 75.88%), medium(by 34.38%), and low(by 74.95%) elevational plots. Species richness had significant linear correlations with SOC, TN, and C: N(Pwarmed treatm

关键词： warming effect Plant diversity pattern Community structure change Elevation gradient Alpine meadow ecosystem Mount wutai

Honeycomb-like biochar framework coupled with Fe_(3)O_(4)/FeS nanoparticles as efficient heterogeneous Fenton catalyst for phenol degradation

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第2期136卷 390-399页

作者： aihua Cheng Yi He Xiaohe Liu Chi He Department of Environmental Engineering College of Geology and EnvironmentXi’an University of Science and TechnologyXi’an 710054China State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power EngineeringXi’an Jiaotong UniversityXi’an 710049China National Engineering Laboratory for VOCs Pollution Control Material and Technology University of Chinese Academy of SciencesBeijing 101408China

Achieving an efficient and stable heterogeneous Fenton reaction over a wide pH range is of great significance for wastewater ***,a pollen-derived biochar catalyst with a unique honeycomb-like structure,coupled with the dispersion of magnetic Fe_(3)O_(4)/FeS(Fe/S)nanoparticles,was synthesized by simple impregnation precursor,followed by *** prepared Fe/S-biochar catalyst demonstrated outstanding phenol degradation efficiency across a wide pH range,with 98%of which eliminated even under neutral conditions(pH 7.0).The high catalytic activity was due to the multilevel porous structure of pollenderived biochar provided enough active sites and allowed for better electron transfer,then increases oxidation ability to promote the ***,the acid microenvironment formed by SO_(4)^(2-)group from Fe/S composite extended the pH range for Fenton reaction,and S^(2-)facilitated the conversion of≡Fe^(3+)to≡Fe^(2+),resulting in remarkable degradation ***,biochar can effectively promote cycling stability by limiting Fe *** work may provide a general strategy for designing 3D framework biochar-based Fe/S catalysts with excellent performance for heterogeneous Fenton reactions.

关键词： Biomass Biochar Fenton reaction Fe_(3)O_(4)/FeS(Fe/S) Phenol degradation

Quantitative assessment of the breast cancer marker HER2 using a gold nanoparticle-based lateral flow immunoassay

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第6期17卷 5452-5460页

作者： Liya Ye Xinxin Xu aihua Qu Liqiang Liu Chuanlai Xu Hua Kuang International Joint Research Laboratory for Biointerface and Biodetection and School of Food Science and TechnologyJiangnan UniversityWuxi 214122China

Human epidermal growth factor receptor 2(HER2)is an important biomarker for detection and treatment of breast *** this study,we developed monoclonal antibodies against the extracellular domain(ECD)of HER2 and established a rapid and accurate lateral flow immunoassay(LFIA)for use in community medical *** gene sequence of human HER2-ECD was obtained from the National Center for Biotechnology Information(NCBI)to construct the expression ***2-ECD protein expressed in HEK293F cells was used to immunize BALB/c *** monoclonal antibodies were produced in mouse ascites and isolated by hybridoma cell *** were analyzed for purity by SDS-PAGE(sodium dodecyl sulphate-polyacrylamide gel-electrophoresis)and affinity was assessed by enzyme-linked immunosorbent assay(ELISA)while subtypes were detected using the commercial *** HER2-ECD test strip was prepared based on the sandwich method and evaluated using a portable detection *** affinity of the paired antibodies,4D8 and 8D9,both reached 1×108 L/*** antibodies specifically recognized the HER2-ECD protein in *** limit of detection(LOD)of the gold nanoparticle(AuNP)-based LFIA was 1.7 ng/mL with a detection range of 1.7-400 ng/mL,and the performance of the HER2-ECD strip correlated well with that of a Siemens chemiluminescent immunoassay(CLIA)*** conclusion,the paired antibodies were successfully prepared with high affinity and *** AuNP-based LFIA of HER2-ECD provides a fast and accurate method to detect the concentration of HER2-ECD in serum samples for clinical use in community medical institutions,and could contribute to determining the progress of the disease or the effectiveness of treatment.

关键词： human epidermal growth factor receptor 2 breast cancer monoclonal antibody quantitative lateral flow immunoassay

Electron vortex generations in photoionization of hydrogen atoms by circularly-polarized chirped attosecond pulses

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2024年第1期76卷 111-118页

作者： Bingshuang Zhang Xiaoyu Liu Fengzheng Zhu Liguang Jiao aihua Liu Institute of Atomic and Molecular Physics Jilin UniversityChangchun 130012China School of Mathematics and Physics Hubei Polytechnic UniversityHuangshi 435003China College of Physics Jilin UniversityChangchun 130012China Helmholtz-Institut Jena D-07743 JenaGermany State Key Laboratory of Transient Optics and Photonics Chinese Academy of SciencesXi'an 710119China

By numerically solving the time-dependent Schr?dinger equation and employing the analytical perturbative model,we investigated the chirp-induced electron vortex in the photoionization of hydrogen atoms by a pair of counter-rotating circularly polarized chirped attosecond extremely ultraviolet *** demonstrated that single-photon ionization of hydrogen atoms generates photoelectron momentum distributions(PMDs)with distinct helical vortex structures either with or without a time delay between two counter-rotating circularly polarized laser *** structures are highly sensitive to both the time delay between the pulses and their chirp *** analytical model reveals that the splitting of vortex spirals is caused by the sign changing of the chirp-induced frequency-dependent time *** showed that to obtain the counterpart of the PMD under a pair of counter-rotating circularly polarized chirped pulses,both chirp parameters and ordering of pulses need to be reversed.

关键词： photoionization ultrafast processes ultrafast dynamics electron vortex

Kerogen Kinetic Distributions and Simulations Provide Insights into Petroleum Transformation Fraction (TF) Profiles of Organic-Rich Shales

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science 2024年第3期35卷 747-757页

作者： David A.wood DwA Energy Limited Lincoln LN59JPUnited Kingdom

Two hundred and fifty single first-order Arrhenius reactions are simulated to generate S2 pyrograms at three heating rates 25,15,and 5°C·*** activation energy(E)and pre-exponential factor(A)of the reactions simulated follow a long-established trend of those variable values displayed by shales and *** characteristics of the transformation fraction(TF)profiles(product generation window temperatures)of the simulated single reactions are compared to the TF profiles of recorded shale pyrograms generated by multiple reactions with different E-A values lying near the defined E-A *** similarities and differences are observed between the TF profile values of the two *** similarities support the spread of E-A values involved in shale pyrogram best *** differences are most likely explained by the complexity of the multiple kerogen first-order and second-order reactions contributing to the recorded shale pyrograms versus the simplicity and crispness of the single first-order reactions *** results also justify the validity of using the previously described“variable E-A pyrogram-fitting method”of multi-heating-rate shale pyrograms enabling optimizers to choose multiple reactions from an unlimited range of E-A *** contrast,further doubt is cast on the validity of the constant-A pyrogram-fitting method used by the Easy%Ro technique,in that a distribution of reactions with a single A value is unlikely to represent the complex variety of kerogen macerals observed in shale *** profiles generated by the variable E-A pyrogram-fitting method lie close to the established E-A trend and are likely to provide more realistic TF generation window temperatures than TF profiles generated by the constant-A pyrogram-fitting method.

关键词： transformation fraction profiles simulated S2 pyrograms multiple heating rates kerogen/shale kinetics S2 pyrogram fitting techniques kerogen petroleum research.

A gold-based multiplex immunochromatographic sensor for detecting paclitaxel

在线全文

学校读者我要写书评

暂无评论

Nano Research 2024年第7期17卷 6420-6429页

作者： Xiaoqian Jiang aihua Qu Xinxin Xu Hua Kuang Liqiang Liu Chuanlai Xu State Key Laboratory of Food Science and Technology Jiangnan UniversityWuxi 214122China International Joint Research Laboratory for Biointerface and Biodetection and School of Food Science and TechnologyJiangnan UniversityWuxi 214122China

Paclitaxel(PTX),methotrexate(MTX),and 5-fluorouracil(5-FU)are commonly-used small molecule anti-tumor drugs for breast ***,drug resistance occurs with long-term treatment or excessive use,and the high concentrations of PTX,MTX,and 5-FU in patients may lead to side effects with dose-limiting toxicities,such as myelosuppression,hepatotoxicity,and peripheral ***,concentration monitoring of PTX,MTX,and 5-FU in clinical treatment is very *** prepared highly sensitive and specific monoclonal antibodies using several haptens,and established a multiple paper-based sensor utilizing optical signals of gold nanoparticles,which simultaneously detected PTX,MTX,and 5-FU in human plasma or urine with 10 min.A portable scanner for quantitative detection in plasma and urine samples was used,and the calculated limit of detection(cLOD)values were 0.002 and 0.142μg/mL for PTX,0.187 and 0.976 ng/mL for MTX,and 0.057 and 0.128μg/mL for 5-FU,*** the recovery test,the recovery rates and the coefficient of variation were 85.84%–108.81%and 1.23%–8.80%,respectively,indicating the reliability and accuracy of the multiple gold immunochromatographic strip(GIS).In addition,for the determination of collected clinical plasma samples,the correlation between the test data of the multiple GIS and liquid chromatography–tandem mass spectrometry(LC–MS/MS)was ***,the developed multiple GIS could be applied to the rapid detection of PTX,MTX,and 5-FU in different clinical samples.

关键词： paclitaxel methotrexate 5-fluorouracil immunochromatographic assay plasma urine

Comparison of debris flow susceptibility assessment methods:support vector machine,particle swarm optimization,and feature selection techniques

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Mountain Science 2024年第2期21卷 397-412页

作者： ZHAO Haijun wEI aihua MA Fengshan DAI Fenggang JIANG Yongbing LI Hui Key Laboratory of Shale Gas and Geoengineering Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Innovation Academy for Earth Science Chinese Academy of SciencesBeijing 100029China Hebei Province Key Laboratory of Sustained Utilization&Development of water Recourse Hebei GEO UniversityShijiazhuang 050031China School of water Resources and Environment Hebei GEO UniversityShijiazhuang 050031China The Sixth Geological Brigade of Geological Mineral Exploration and Development Bureau of Hebei Province Shijiazhuang 050085China

The selection of important factors in machine learning-based susceptibility assessments is crucial to obtain reliable susceptibility *** this study,metaheuristic optimization and feature selection techniques were applied to identify the most important input parameters for mapping debris flow susceptibility in the southern mountain area of Chengde City in Hebei Province,China,by using machine learning *** total,133 historical debris flow records and 16 related factors were *** support vector machine(SVM)was first used as the base classifier,and then a hybrid model was introduced by a two-step ***,the particle swarm optimization(PSO)algorithm was employed to select the SVM model ***,two feature selection algorithms,namely principal component analysis(PCA)and PSO,were integrated into the PSO-based SVM model,which generated the PCA-PSO-SVM and FS-PSO-SVM models,*** statistical metrics(accuracy,recall,and specificity)and the area under the receiver operating characteristic curve(AUC)were employed to evaluate and validate the performance of the *** results indicated that the feature selection-based models exhibited the best performance,followed by the PSO-based SVM and SVM ***,the performance of the FS-PSO-SVM model was better than that of the PCA-PSO-SVM model,showing the highest AUC,accuracy,recall,and specificity values in both the training and testing *** was found that the selection of optimal features is crucial to improving the reliability of debris flow susceptibility assessment ***,the PSO algorithm was found to be not only an effective tool for hyperparameter optimization,but also a useful feature selection algorithm to improve prediction accuracies of debris flow susceptibility by using machine learning *** high and very high debris flow susceptibility zone appropriately covers 38.01%of the study area,where debris flow may occur under intens

关键词： Chengde Feature selection Support vector machine Particle swarm optimization Principal component analysis Debris flow susceptibility