检索结果-南通市图书馆

Sparse Tensor Prior for Hyperspectral,Multispectral,and Panchromatic Image Fusion

在线全文

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2023年第1期10卷 284-286页

作者： xin tian Wei Zhang Dian yu Jiayi Ma the Electronic Information School Wuhan UniversityWuhan 430072China

Dear Editor, This letter is concerned with a new hyperspectral fusion paradigm by simultaneously fusing hyperspectral, multispectral, and panchromatic images. Seeking an efficient prior about the target hyperspectral image(HSI), is vital for constructing an accurate fusion model in this problem. To this end, this work suggests a novel sparse tensor prior using patch-based sparse tensor dictionary learning.

关键词： spectral patch concerned

Effect of austempering time on microstructure and properties of a low-carbon bainite steel

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2020年第3期27卷 340-346页

作者： Man Liu Guang Xu Jun-yu tian Qing yuan xin Chen The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and Technology

The effect of austempering time after the bainitic transformation on the microstructure and property in a low-carbon bainite steel was investigated by metallography and dilatometry. The results showed that by prolonging the austempering time after the bainite transformation, the amount of large-size martensite/austenite islands decreased, but no significant change of the amount and morphology of bainite were observed. In addition, more austenite with a high carbon content was retained by prolonging the holding time at the bainite transformation ***, with a longer holding time, the elongation was improved at the expense of a small decrease in tensile strength. Finally, the Avrami equation B(RF) = 1-exp(-0.0499 × t^0.7616) for bainite reaction at 350℃ was obtained for the tested steel. The work provided a reference for tailoring the properties of low-carbon steels.

关键词： austempering time retained austenite martensite/austenite island low-carbon bainite transformation kinetics

应用风险评估数学模型对沙井街道企业作业场所中有机毒物排序分析

在线全文

学校读者我要写书评

暂无评论

职业与健康 2015年第24期31卷 3376-3378页

作者：邱星元边寰锋余新天代浩谢亮广东省深圳市宝安区沙井预防保健所 518104 武汉科技大学医学院公共卫生学院

目的建立深圳市沙井街道涉有机溶剂企业作业场所优先控制、排序的风险评估数学模型,探讨其在职业病预防工作的作用,以达到从管理上优先治理和控制涉有机溶剂职业病危害较重的作业场所。方法以沙井街道涉有机溶剂作业场所为研究对象,借... 详细信息

目的建立深圳市沙井街道涉有机溶剂企业作业场所优先控制、排序的风险评估数学模型,探讨其在职业病预防工作的作用,以达到从管理上优先治理和控制涉有机溶剂职业病危害较重的作业场所。方法以沙井街道涉有机溶剂作业场所为研究对象,借鉴美国毒物与疾病登记署(ATSDR)和环境保护署(EPA)的优先污染物筛选和排序方法及国内外先进经验,建立风险评估数学模型。结果涉有机溶剂企业共调查160家,在涉有机溶剂企业作业场所中检测的9种有机溶剂中,共检测1 964个点,能取得出数值的有168个点,其中超标的有56个点。超标点中存在的有毒物质为甲苯、二甲苯、三氯乙烯和正己烷,超标率分别为2.7%、1.4%、47.6%、1.4%。涉有机溶剂企业优先控制排序的有机毒物依次是三氯乙烯、甲苯、正己烷、二甲苯、苯、乙酸乙酯、丙酮、丁酮、乙酸丁酯。结论建立涉有机溶剂企业优先控制排序数学模型对该街道预防职业病有重要的指导意义。

关键词：工作场所有机溶剂风险评估数学模型排序

Thermal and mechanical properties and micro-mechanism of SiO_(2)/epoxy nanodielectrics

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2021年第12期30卷 613-619页

作者： tian-yu Wang Gui-xin Zhang Da-yu Li Department of Electrical Engineering Tsinghua UniversityBeijing 100084China

In addition to electrical insulation properties,the thermal properties of nanodielectrics,such as glass transition temperature,thermal expansion coefficients,thermal conductivity,and mechanical properties,including Young's modulus,bulk modulus,and shear modulus,are also very *** paper describes the molecular dynamics simulations of epoxy resin doped with SiO_(2)nanoparticles and with SiO_(2)nanoparticles that have been surface grafted with hexamethyldisilazane(HMDS)at 10%and 20%grafting *** results show that surface grafting can improve certain thermal and mechanical properties of the *** analysis indicates that the improved thermal performance occurs because the formation of thermal chains becomes easier after the surface grafting *** improved mechanical properties originate from two ***,doping with SiO_(2)nanoparticles inhibits the degree of movement of molecular chains in the ***,the surface grafting treatment weakens the molecular repulsion between SiO_(2)and epoxy resin,and the van der Waals excluded region becomes ***,the compatibility between SiO_(2)nanoparticles and polymers is improved by the grafting *** analysis method and conclusions in this paper provide guidance and reference for the future studies of the thermal and mechanical properties of nanodielectrics.

关键词： nanodielectric surface grafting treatment molecular dynamics simulation interface properties

Bifurcations of Limit Cycles in A Perturbed Quintic Hamiltonian System with Six Double Homoclinic Loops

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2008年第2期24卷 313-328页

作者： Yong-xi Gao yu-hai Wu Li-xin tian Department of Mathematics Jiang Su University Zhenjiang 212013 China

This paper concerns with the number and distributions of limit cycles of a quintic subject to a seven-degree perturbation. With the aid of numeric integral computation provided by Mathematica 4.1, at least 45 limit cycles are found in the above system by applying the method of double homoclinic loops bifurcation, Hopf bifurcation and qualitative analysis. The four configurations of 45 limit cycles of the system are also shown. The results obtained are useful to the study of the weakened 16th Hilbert Problem.

关键词： limit cycles the Hilbert's 16th problem the double homoclinic loops stability Poincare-Bendixsontheorem

Bifurcations of Limit Cycles in a Z_4-Equivariant Quintic Planar Vector Field

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2010年第4期26卷 779-798页

作者： yu Hai WU Xue Di WANG Li xin tian Department of Mathematics Jiangsu University Zhenjiang 212013 P. R. China

In this paper, a Z4-equivariant quintic planar vector field is studied. The Hopf bifurcation method and polycycle bifurcation method are combined to study the limit cycles bifurcated from the compounded cycle with 4 hyperbolic saddle points. It is found that this special quintic planar polynomial system has at least four large limit cycles which surround all singular points. By applying the double homoclinic loops bifurcation method and Hopf bifurcation method, we conclude that 28 limit cycles with two different configurations exist in this special planar polynomial system. The results acquired in this paper are useful for studying the weakened 16th Hilbert＇s Problem.

关键词： compounded cycle double homoclinic loops stability bifurcation limit cycles distribution of limit cycles

高光谱预处理方法与多模型在分类判别中的对比研究

在线全文

学校读者我要写书评

暂无评论

光谱学与光谱分析 2025年第1期45卷 125-132页

作者：居雷于洁吴炎淼李丽卢天丁亚萍束茹欣上海烟草集团有限责任公司技术中心上海200082 上海大学化学系上海200444 上海数之微信息科技有限公司上海200444

高光谱技术能够快速、无损地获取丰富的信息,在植物研究和监测中已成为一种广泛应用的工具。茄科植物作为一种重要的经济农作物,与高光谱技术结合进行研究具有巨大的应用潜力。本研究采用高光谱技术对茄科植物的初烤后不同部位叶片进行... 详细信息

高光谱技术能够快速、无损地获取丰富的信息,在植物研究和监测中已成为一种广泛应用的工具。茄科植物作为一种重要的经济农作物,与高光谱技术结合进行研究具有巨大的应用潜力。本研究采用高光谱技术对茄科植物的初烤后不同部位叶片进行分类研究。采用Field Spec 3光谱辐射仪对293份不同部位的茄科植物粉末样本进行高光谱采样,采用S-G平滑以及一阶导数和二阶导数的方法对数据进行预处理,用于信息增强和去除噪声,并通过偏最小二乘法对数据进行降维,以减少冗余特征。基于降维数据,采样支持向量机、逻辑回归、K近邻、决策树、随机森林和梯度提升决策树这六种机器学习算法建立分类模型。结果显示,在分类任务中,经过一阶导数处理后,支持向量机模型最佳,在训练集和测试集上分别实现了100.0%和84.7%的准确率。经网格参数优化后确定最优参数为:最大深度不限制,最小样本分割数为4,估计器数量为200。参数优化后五折交叉验证准确率为88.1%,训练集准确率为100%,测试集准确率为86.4%。研究结果表明,预处理方法结合降维方法能够增强数据信息使得分类模型能够更好地捕捉茄科植物样本的特征。该研究对于快速、准确、无损地区分茄科植物的部位具有重要意义。

关键词：高光谱部位分类机器学习

Improved Plasmonic Hot‑Electron Capture in Au Nanoparticle/Polymeric Carbon Nitride by Pt Single Atoms for Broad‑Spectrum Photocatalytic H_(2)Evolution

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2023年第8期15卷 423-435页

作者： Manyi Gao Fenyang tian xin Zhang Zhaoyu Chen Weiwei Yang Yongsheng yu MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin 150001HeilongjiangPeople’s Republic of China Space Environment Simulation Research Infrastructure Harbin Institute of TechnologyHarbin 150001People’s Republic of China

ABSTRACT Rationally designing broad-spectrum photocatalysts to harvest whole visible-light region photons and enhance solar energy conversion is a“holy grail”for researchers,but is still a challenging ***,based on the common polymeric carbon nitride(PCN),a hybrid co-catalysts system comprising plasmonic Au nanoparticles(NPs)and atomically dispersed Pt single atoms(PtSAs)with different functions was constructed to address this *** the dual co-catalysts decorated PCN(PtSAs–Au_(2.5)/PCN),the PCN is photoexcited to generate electrons under UV and short-wavelength visible light,and the synergetic Au NPs and PtSAs not only accelerate charge separation and transfer though Schottky junctions and metal-support bond but also act as the co-catalysts for H_(2) ***,the Au NPs absorb long-wavelength visible light owing to its localized surface plasmon resonance,and the adjacent PtSAs trap the plasmonic hot-electrons for H_(2) evolution via direct electron transfer ***,the PtSAs–Au_(2.5)/PCN exhibits excellent broad-spectrum photocatalytic H_(2) evolution activity with the H_(2) evolution rate of 8.8 mmol g^(−1) h^(−1) at 420 nm and 264μmol g^(−1) h^(−1) at 550 nm,much higher than that of Au_(2.5)/PCN and PtSAs–PCN,*** work provides a new strategy to design broad-spectrum photocatalysts for energy conversion reaction.

关键词： Polymeric carbon nitride Au nanoparticles Pt single atoms Photocatalytic H2 evolution Broad-spectrum photocatalysts

阿奇霉素序贯治疗联合麻杏石甘汤加味对痰热闭肺型肺炎支原体肺炎患儿Th17/Treg细胞因子和NLRP3炎症小体通路的影响

在线全文

学校读者我要写书评

暂无评论

现代生物医学进展 2022年第12期22卷 2328-2332页

作者：于欣田孙冬冬胡红蕾李宇哲刁娟娟山东中医药大学第一临床医学院山东济南250014 山东省中医院儿科山东济南250014

目的:观察阿奇霉素序贯治疗联合麻杏石甘汤加味对痰热闭肺型肺炎支原体肺炎(MPP)患儿辅助性T细胞17(Th17)/调节性T细胞(Treg)细胞因子和NOD样受体蛋白3(NLRP3)炎症小体通路的影响。方法:选择山东省中医院2019年4月~2021年5月期间收治的... 详细信息

目的:观察阿奇霉素序贯治疗联合麻杏石甘汤加味对痰热闭肺型肺炎支原体肺炎(MPP)患儿辅助性T细胞17(Th17)/调节性T细胞(Treg)细胞因子和NOD样受体蛋白3(NLRP3)炎症小体通路的影响。方法:选择山东省中医院2019年4月~2021年5月期间收治的痰热闭肺型MPP患儿106例,根据随机数字表法分为对照组和研究组,各为53例,对照组患儿接受阿奇霉素序贯治疗,研究组患儿接受阿奇霉素序贯治疗联合麻杏石甘汤加味治疗,对比两组疗效、中医证候积分、Th17/Treg细胞因子和NLRP3炎症小体通路相关指标,记录两组不良反应发生情况。结果:与对照组相比,研究组的临床总有效率明显更高(P<0.05)。两组治疗后次证积分、主证积分、总积分均较治疗前下降,且研究组低于对照组(P<0.05)。两组治疗后白介素-17A(IL-17A)、白介素-25(IL-25)水平均较治疗前下降,白介素-10(IL-10)、白介素-35(IL-35)水平均较治疗前升高,且研究组的变化程度大于对照组(P<0.05)。两组治疗后NLRP3 m RNA、接头蛋白凋亡相关斑点样蛋白(ASC)m RNA、半胱天冬酶1(caspase-1)m RNA均较治疗前下降,且研究组的下降程度大于对照组(P<0.05)。两组在治疗期间均未曾出现明显不良反应。结论:阿奇霉素序贯治疗联合麻杏石甘汤加味治疗痰热闭肺型MPP患儿疗效显著,可促进症状改善,作用机制可能与调节Th17/Treg细胞因子和NLRP3炎症小体通路有关。

关键词：阿奇霉素麻杏石甘汤加味痰热闭肺型肺炎支原体肺炎 Th17/Treg细胞因子 NLRP3炎症小体通路