检索结果-南通市图书馆

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

采用小波变换的空间外差干涉图误差分析方法

光谱学与光谱分析 2025年第1期45卷 8-14页

作者：王方原李晓静叶松李树王新强桂林电子科技大学光电工程学院广西桂林541004 广西光电信息处理重点实验室广西桂林541004

空间外差光谱技术(SHS)是一种应用于微弱物质探测、行星勘探以及大气遥感等领域的超光谱分析技术。受实验环境复杂及被测目标信号微弱等因素的影响,空间外差光谱仪的测量结果易出现干涉条纹倾斜、干涉图有斑点噪声等情况,从而最终影响... 详细信息

空间外差光谱技术(SHS)是一种应用于微弱物质探测、行星勘探以及大气遥感等领域的超光谱分析技术。受实验环境复杂及被测目标信号微弱等因素的影响,空间外差光谱仪的测量结果易出现干涉条纹倾斜、干涉图有斑点噪声等情况,从而最终影响测量光谱的精度。为了尝试解决这些问题,提出了基于小波变换的干涉图误差分析方法,对干涉图的斑点噪声水平和条纹倾斜误差进行有效的评价,从而为后续误差校正提供理论基础。首先对无误差的钾灯仿真干涉图加入不同标准差的高斯噪声,利用小波分解提取复小波系数,采用三种噪声估计法对干涉图数据进行计算,结果表明空域相关小波变换法噪声估计结果与真实值偏差最小,而Donoho估计法在修正截距后与真实值具有更好的吻合度。随后采用Db2小波对噪声水平不同的仿真钾灯干涉图进行一层小波分解并提取水平、对角及垂直三个方向的细节系数,采用Donoho估计法对干涉图进行二维噪声分析,有效表征了三幅干涉图各方向上的噪声水平特征。最后对仿真连续光干涉图进行小波分解并提取系数分析,研究了干涉条纹倾斜角度与小波分解系数的关系。研究结果表明,三个方向的小波细节系数估值变化分别在分解到不同层数时具有相似的变化规律:小波细节系数估值与条纹倾斜方向和小波细节系数的所属方向的夹角成反比,条纹倾斜方向与该小波细节系数的方向夹角越小,估值越大,反之则越小,且水平方向分解到第一层、对角方向分解到第二层、垂直方向分解到第三层符合变化规律。该研究是利用小波分解进行空间外差光谱误差分析的有益尝试,也为后续干涉图条纹倾斜误差的校正提供了一种新途径。

关键词：空间外差光谱技术噪声标准差估计干涉图小波变换

在线全文

学校读者我要写书评

暂无评论

一种适合工业化生产的溴甲纳曲酮的制备方法

广东化工 2016年第22期43卷 28-29页

作者：徐溶熔罗宏军宣景安李国贤梅来宝南京工业大学江苏南京210000 扬子江药业集团有限公司江苏泰州225300

以盐酸纳曲酮为原料,先用乙酸酐保护其酚羟基,再和溴甲烷进行N-甲基化反应,所得反应物再用氢溴酸水解得到溴甲纳曲酮,总收率35%,HPLC纯度大于99.9%,该制备方法操作简单,适合工业化生产。

关键词：溴甲纳曲酮便秘合成

Mechanism of action of linggui Zhugan Decoction in treating non-alcoholic fatty liver disease using untargeted metabolomics approach

在线全文

学校读者我要写书评

暂无评论

Traditional Medicine Research 2025年第2期10卷 65-76页

作者： Huan Pei Ren-lin li Xin-Ran Song Qian-Qian Wan Yu-Ming Wang Han-Zhou li Wei-Quan Xu Jia-Bao liao Wei-Bo Wen jing Miao Huan-Tian Cui School of Basic Medicine Yunnan University of Chinese MedicineKunming 650599China School Clinical Medical College Yunnan University of Chinese MedicineKunming 650599China First School of Clinical Medicine Yunnan University of Chinese MedicineKunming 650599China School of Integrative Chinese and Western Medicine Tianjin University of Traditional Chinese MedicineTianjin 301617China Department of Pharmacy Tianjin Second People's HospitalTianjin 300192China

Background:Non-alcoholic fatty liver disease(NAFLD)is a liver disorder characterized by the accumulation and degeneration of fat in the liver cells,a condition that may further deteriorate and lead to cirrhosis and liver *** studies showed that metabolic dysfunction can promote NAFLD *** Zhugan Decoction(LGZGD)has therapeutic effects on *** mechanism of LGZGD still remains *** study was to examine the impact of LGZGD on the metabolic processes involved in the development of ***:A mice model of NAFLD was treated with *** therapeutic potential of LGZGD was evaluated by assessing the activity of transaminases,lipids levels of blood,and pathological changes in the liver of the mice model of ***,this study also evaluated the influence of LGZGD on liver inflammation and oxidative ***:The results of untargeted metabolomics analysis showed that LGZGD reduced the disordered lipid metabolism in NAFLD *** improved the oxidative stress and also reduced the levels of pro-inflammatory cytokines in the *** metabolomics analysis of liver samples revealed that LGZGD treatment improved metabolic disorders,including alanine,aspartate,glutamate,glycerophospholipid metabolism,and citrate *** RT-qPCR and Western blot results showed that LGZGD could regulate the expression of key enzymes in the metabolic pathway of the citrate cycle,including ATP-citrate lyase(ACLY),alanine-glyoxylate aminotransferase-2(AGXT2),phosphatidylethanolamine N-methyltransferase(PEMT),and succinate dehydrogenase(SDH).Conclusion:We found that LGZGD can treat NAFLD by reducing inflammatory responses,inhibiting oxidative stress,regulating alanine,aspartate,glutamate,and glycerophospholipid metabolism,and citrate cycle pathways.

关键词： NAFLD LGZGD untargeted metabolomics glycerophospholipid metabolism citrate cycle

基于多分支增强和融合注意力机制的水下图像增强算法

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

陕西科技大学学报 2025年第1期43卷 193-202页

作者：姚斌韩典芝徐轩李婉陕西科技大学电子信息与人工智能学院陕西西安710021

由于水对光的折射和吸收,水下图像通常会出现严重的退化,如色偏、模糊、能见度低等.为了提高水下图像的可视性,提出了一种基于多分支增强和融合注意力机制的水下图像增强网络MBFA-GAN.首先,通过分析水下图像的色彩退化和模糊因素,设计... 详细信息

由于水对光的折射和吸收,水下图像通常会出现严重的退化,如色偏、模糊、能见度低等.为了提高水下图像的可视性,提出了一种基于多分支增强和融合注意力机制的水下图像增强网络MBFA-GAN.首先,通过分析水下图像的色彩退化和模糊因素,设计了青品色温修复模块和模糊恢复模块对水下图像进行色彩矫正和模糊恢复.然后,基于对多个分支特征的互补性考虑,采用循环合并策略将多个分支增强的特征利用自适应融合模块进行融合,逐步增强图像细节.最后,设计了融合注意力模块,用于深度挖掘图像在通道维度和像素维度的相关性矩阵,以提高增强图像的真实性.实验结果表明,与现有算法相比,提出的水下图像增强算法去模糊效果较好且颜色更真实,可以有效改善水下图像色偏和模糊的问题.

关键词：水下图像增强多分支增强融合注意力生成对抗网络

Free vibration analysis of functionally graded material beams based on Levinson beam theory

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2016年第7期37卷 861-878页

作者： xuan WANG Shirong li School of Hydraulic Energy and Power Engineering Yangzhou University School of Civil Science and Engineering Yangzhou University

Free vibration response of functionally graded material （FGM） beams is studied based on the Levinson beam theory （LBT）. Equations of motion of an FGM beam are derived by directly integrating the stress-form equations of elasticity along the beam depth with the inertial resultant forces related to the included coupling and higherorder shear strain. Assuming harmonic response, governing equations of the free vibration of the FGM beam are reduced to a standard system of second-order ordinary differential equations associated with boundary conditions in terms of shape functions related to axial and transverse displacements and the rotational angle. By a shooting method to solve the two-point boundary value problem of the three coupled ordinary differential equations, free vibration response of thick FGM beams is obtained numerically. Particularly, for a beam with simply supported edges, the natural frequency of an FGM Levinson beam is analytically derived in terms of the natural frequency of a corresponding homogenous Euler-Bernoulli beam. As the material properties are assumed to vary through the depth according to the power-law functions, the numerical results of frequencies are presented to examine the effects of the material gradient parameter, the length-to-depth ratio, and the boundary conditions on the vibration response.

关键词： functionally graded material (FGM) beam Levinson beam theory (LBT),free vibration shooting method natural frequency

Fecal microbiota transplantation as potential first-line treatment for patients with Clostridioides difficile infection and prior appendectomy

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastrointestinal Surgery 2023年第2期15卷 303-306页

作者： jing-Wen Zhao Bing Chang li-xuan Sang Department of Gastroenterology Shengjing Hospital of China Medical UniversityShenyang 110022Liaoning ProvinceChina Department of Gastroenterology The First Affiliated Hospital of China Medical UniversityShenyang 110001Liaoning ProvinceChina

Clostridioides difficile infection(CDI)is a global health *** association of appendectomy on the severity and prognosis of CDI has been reported in many literatures,but there are still *** a retrospective study entitled“Patients with Closterium diffuse infection and prior appendectomy may be prone to word outcomes”published in World J Gastrointest Surg 2021,the author found that prior appendectomy affects the severity of *** may be a risk factor for increasing the severity of ***,it is necessary to seek alternative treatment for patients with prior appendectomy when they are more likely to have severe or fulminant CDI.

关键词： Clostridioides difficile infection Appendectomy Fecal microbiota transplantation Intestinal microbiota Toxic megacolon Colectomy

Multi-Physics Modeling of Solid Oxide Fuel Cell Fueled by Methane and Analysis of Carbon Deposition

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Physics 2015年第3期28卷 299-307,I0001页

作者： Bao-xuan Wang Jiang Zhu Zi-jing lin Hefei National Laboratory for Physical Sciences at the Microscale & Collaborative Innovation Center of Suzhou Nano Science and Technology University of Science and Technology of China Hefei 230025 China Key Laboratory of Strongly-Coupled Quantum Matter Physics Chinese Academy of Sciences and Department of Physics University of Science and Technology of China Hefei 230025 China

Internal reformation of low steam methane fuel is important for the high efficiency and low cost operation of solid oxide fuel cell. Understanding and overcoming carbon deposition is crucial for the technology development. Here a multi-physics model is established for the relevant experimental cells. Balance of electrochemical potentials for the electrochemical reactions, generic rate expression for the methane steam reforming, dusty gas model in a form of Fick＇s model for anode gas transport are used in the model. Excellent agreement between the theoretical and experimental current-voltage relations is obtained, demonstrating the validity of the proposed theoretical model. The steam reaction order in low steam methane reforming reaction is found to be 1. Detailed information about the distributions of physical quantities is obtained by the numerical simulation. Carbon deposition is analyzed in detail and the mechanism for the coking inhibition by operating current is illustrated clearly. Two expressions of carbon activity are analyzed and found to be correct qualitatively, but not quantitatively. The role of anode diffusion layer on reducing the current threshold for carbon removal is also explained. It is noted that the current threshold reduction may be explained quantitatively with the carbon activity models that are only qualitatively correct.

关键词： Numerical model Methane reforming kinetics Current-voltage relation Carbon activity Diffusion barrier layer

基于Ollivier-Ricci曲率的图扩散节点分类算法

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

计算机应用研究 2025年第1期42卷 165-170页

作者：孙宁李胤萱张帅汤璇魏宪辽宁工程技术大学软件学院辽宁葫芦岛125105 华东师范大学软件工程学院上海200241

为解决图扩散方法在处理复杂边关系时精度降低的局限性,提出了一种基于曲率的图扩散神经网络。首先,引入Ollivier-Ricci曲率量化图的边曲率,提供关于图结构的几何度量;其次,运用曲率调整随机转移矩阵的权重,根据几何关系进行相应的权重... 详细信息

为解决图扩散方法在处理复杂边关系时精度降低的局限性,提出了一种基于曲率的图扩散神经网络。首先,引入Ollivier-Ricci曲率量化图的边曲率,提供关于图结构的几何度量;其次,运用曲率调整随机转移矩阵的权重,根据几何关系进行相应的权重修改;最后,将处理后的曲率矩阵与图扩散矩阵结合,更新权重系数进行模型训练。实验结果表明,与传统的图扩散方法相比,改良后的方法保持了有效地平滑图信号和减少高频噪声的优点,并在不同边和节点数量的数据集上将精度提高0.3~2.0百分点。该方法通过优化图扩散的消息聚合,能够更有效地利用图结构中的节点信息和边权重,从而提升节点分类任务中的模型性能,为未来基于图方法的研究提供了更可靠的方法与实验。

关键词：图神经网络图扩散 Ollivier-Ricci曲率节点分类

Visible light-mediated C—P bond formation reactions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science Bulletin 2019年第5期64卷 337-350页

作者： Bao-Gui Cai Jun xuan Wen-jing Xiao Anhui Province Key Laboratory of Chemistry for Inorganic/Organic Hybrid Functionalized Materials College of Chemistry & Chemical Engineering Anhui University Key Laboratory of Pesticide & Chemical Biology Ministry of Education College of Chemistry Central China Normal University

Organophosphorus compounds have attracted continuous attention in materials science, agrochemical and pharmaceutical fields due to their unique bioactivities. Thus, the development of novel and robust manners for the construction new C—P bond has therefore gained great interests in synthetic organic chemistry. Because of their intrinsic sustainability and green chemistry character, visible light-induced photoredox catalysis has been widely applied in the construction of new chemical bonds, including the formation of C—P bond. In this review, we summarized recent achievements in C—P bond formation reactions initiated by visible light-induced photoredox catalysis, which mainly focusing on the discussion of reaction design and the mechanism.

关键词： C-P bond formation Organophosphorus compounds Photoredox catalysis Visible light