检索结果-南通市图书馆

Inexact proximal gradient algorithm with random reshuffling for nonsmooth optimization

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

Science China(Information Sciences) 2025年第1期68卷 219-237页

作者： xia JIANG Yanyan FANG xianlin ZENG Jian sun Jie CHEN National Key Lab of Autonomous Intelligent Unmanned Systems School of AutomationBeijing Institute of Technology Beijing Institute of Technology Chongqing Innovation Center School of Electronic and Information Engineering Tongji University

Proximal gradient algorithms are popularly implemented to achieve convex optimization with nonsmooth regularization. Obtaining the exact solution of the proximal operator for nonsmooth regularization is challenging because errors exist in the computation of the gradient; consequently, the design and application of inexact proximal gradient algorithms have attracted considerable attention from researchers. This paper proposes computationally efficient basic and inexact proximal gradient descent algorithms with random reshuffling. The proposed stochastic algorithms take randomly reshuffled data to perform successive gradient descents and implement only one proximal operator after all data pass through. We prove the convergence results of the proposed proximal gradient algorithms under the sampling-without-replacement reshuffling *** computational errors exist in gradients and proximal operations, the proposed inexact proximal gradient algorithms can converge to an optimal solution neighborhood. Finally, we apply the proposed algorithms to compressed sensing and compare their efficiency with some popular algorithms.

关键词： proximal operator random reshuffling inexact computation compressed sensing nonsmooth optimization

Intermolecular reductive coupling of aliphatic ketones with alkynes and alkenes by BCN photocatalysts

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2025年第1期68卷 181-185页

作者： Yanping xia Luyang sun Jiajia Cheng Sibo Wang Meifang Zheng Xinchen Wang State Key Laboratory of Photocatalysis on Energy and Environment College of Chemistry Fuzhou University

A photocatalytic process was developed for intermolecular reductive coupling of aliphatic ketones with alkynes/alkenes to furnish tertiary alcohols. Mechanistic studies support that boron carbonitrides(BCN) promote the single electron reduction of unactivated aliphatic ketones to generate ketyl radicals with visible light irradiation, which then react with alkynes and alkenes to afford the allylic and aliphatic alcohols, respectively. The heterogeneous photocatalytic system is compatible with diverse substrates including pharmaceutical-related molecules(43 examples) with reusability and scale-up experiments, verifying the complementary synthetic utility of this method to the homogeneous catalysts.

关键词： aliphatic ketones ketyl radical intermolecular cross-coupling tertiary alcohols

Efficient OpenMP Based Z-curve Encoding and Decoding Algorithms

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2025年第1期82卷 1313-1327页

作者： Zicheng Zhou Shaowen sun Teng Liang Mengjuan Li Fengling xia School of Electronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu611731China Faculty of Information Engineering and Automation Kunming University of Science and TechnologyKunming650500China School of Communications Information Engineering Yunnan Communications Vocational and Technical CollegeKunming650500China Library Yunnan Normal UniversityKunming650500China Faculty of Civil Aviation and Aeronautics Kunming University of Science and TechnologyKunming650500China

Z-curve’s encoding and decoding algorithms are primely important in many Z-curve-based *** bit interleaving algorithm is the current state-of-the-art algorithm for encoding and decoding *** simple,its efficiency is hindered by the step-by-step coordinate shifting and bitwise *** tackle this problem,we first propose the efficient encoding algorithm LTFe and the corresponding decoding algorithm LTFd,which adopt two optimization methods to boost the algorithm’s efficiency:1)we design efficient lookup tables(LT)that convert encoding and decoding operations into table-lookup operations;2)we design a bit detection mechanism that skips partial order of a coordinate or a Z-value with consecutive 0s in the front,avoiding unnecessary iterative *** propose order-parallel and point-parallel OpenMP-based algorithms to exploit the modern multi-core *** results on discrete,skewed,and real datasets indicate that our point-parallel algorithms can be up to 12.6×faster than the existing algorithms.

关键词： Z-curve lookup table OpenMP bit detection mechanism

CaH2-promoted activity of Ni-carbonate interface for CO2 methanation

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

Journal of Energy Chemistry 2025年第1期100卷 522-532页

作者： Jin-Peng Wang Guo-Cui Mao Hui-Lin Jiang Bao-xia Dong yun-Lei Teng School of Chemistry and Chemical Engineering Yangzhou University

Transition metal-carbonate interfaces often act as active sites in heterogeneous catalytic *** interface between transition metal and metal carbonate exhibits a dynamic equilibrium during the CO2hydrogenation reaction,involving surface carbonate hydrogenation and ***,there have been few reports on engineering the activity of the interface between transition metal and alkaline earth metal carbonate for catalytic *** work demonstrated that the incorporation of CaH2in Ni/CaCO3enhances the CO2methanation activity of the *** CO2conversion for Ni/CaH2-CaCO3reached 68.5%at 400°C,which was much higher than that of the Ni/CaCO3（31.6%） and Ni/CaH2-CaO （42.4%） ***,the Ni/CaH2-CaCO3catalysts remained stable during the stability test for 24 h at 400°C and 8 *** research revealed that CaH2played a crucial role in promoting the activity of the Ni-carbonate interface for ***2could modify the electronic structure of Ni and tune the structural properties of CaCO3to generate medium basic sites （OH groups）,which are favorable for the activation of H2and ***-situ Fourier transform infrared spectroscopy （FTIR） analysis combined with density functional theory calculations demonstrated that CO2activation occurs at the hydroxyl group （OH） on the CaH2-modified Ni-carbonate surface,leading to the formation of CO3H****,our study has confirmed that CO2methanation over the Ni/CaH2-CaCO3catalysts proceeds via the formate pathway.

关键词： CO 2 methanation Metal hydride Ni catalysts Carbonate Metal-carbonate interface

Visualization of the protective role of estrogen against female liver fibrosis via an ER viscosity NIR fluorescent probe

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2025年第1期68卷 360-368页

作者： Zheng Liu Changyu Zhang Zipeng Li Wanying Ma Jia Liu xiang xia Ning Xu Wen sun Jianjun Du Jiangli Fan xiaojun Peng State Key Laboratory of Fine Chemicals Dalian University of Technology Ningbo Institute of Dalian University of Technology

Endoplasmic reticulum(ER) viscosity has emerged as a new potential biomarker for hepatic fibrosis(HF). Herein, we report the first ER-targeting viscosity-responsive near-infrared(NIR) fluorescent probe HBT-PP for investigations of HF *** twisted intramolecular charge transfer(TICT) and the excited state intramolecular proton transfer(ESIPT) are combined to endow HBT-PP with the selective response towards viscosity(～62-fold) and a super large stokes shift(～320 nm). HBT-PP mainly targets organelle ER and is able to image the drug-or alcohol-induced viscosity elevation in living cells. Significantly,HBT-PP was successfully applied to visualize the gender difference in HF and the protective role of estrogen in restraining HF progression. Of note, after 10 min of stain with HBT-PP, HF lesions showed a stage-based response, indicating the potential of this probe in fast and early diagnosis of HF. These results clearly demonstrated the promising application of HBT-PP as a new tool for exploring ER viscosity-involved physiological and pathological processes.

关键词： NIR fluorescent probe ER viscosity hepatic fibrosis gender difference estrogen

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

考虑结构误差的导弹可靠性仿真研究

系统仿真学报 2004年第2期16卷 333-336页

作者：陈云霞孙宇锋康锐北京航空航天大学可靠性工程研究所北京100083

提出了在结构误差的影响下进行导弹飞控系统可靠性分析的方法。建立了四种结构误差即弹体质量分布不对称、弹体不同轴、翼面安装角误差和舵面机械零位误差的扰动模型,给定了各种结构误差的随机变量的分布形式,并采取数字仿真和统计分析... 详细信息

提出了在结构误差的影响下进行导弹飞控系统可靠性分析的方法。建立了四种结构误差即弹体质量分布不对称、弹体不同轴、翼面安装角误差和舵面机械零位误差的扰动模型,给定了各种结构误差的随机变量的分布形式,并采取数字仿真和统计分析的方法进行了结构误差对导弹飞控系统可靠性的影响分析。文中给出了可靠性仿真的算法流程、具体实现途径和相关可靠性指标的计算公式。最后以某型导弹飞控系统为案例验证了该方法的可行性。

关键词：可靠性仿真结构误差飞行控制系统导弹

维普期刊数据库

ATRP法制备聚(甲基丙烯酸氨乙酯-co-甲基丙烯酸N,N-二乙基氨乙基酯)基因载体

在线全文

学校读者我要写书评

暂无评论

高分子学报 2015年第1期25卷 113-119页

作者：孙云霞林斌磊王庆蓉张先正卓仁禧武汉大学化学与分子科学学院生物医用高分子材料教育部重点实验室武汉430072

为得到低毒、高效的聚阳离子基因载体,以甲基丙烯酸氨乙酯（AMA）和甲基丙烯酸N,N-二乙基氨乙基酯（DEAEMA）为单体,以2-溴代异丁酸乙酯（EBIB）为引发剂,通过原子转移自由基聚合（ATRP）制备了两种聚（甲基丙烯酸氨乙酯-co-甲基丙烯酸N... 详细信息

为得到低毒、高效的聚阳离子基因载体,以甲基丙烯酸氨乙酯（AMA）和甲基丙烯酸N,N-二乙基氨乙基酯（DEAEMA）为单体,以2-溴代异丁酸乙酯（EBIB）为引发剂,通过原子转移自由基聚合（ATRP）制备了两种聚（甲基丙烯酸氨乙酯-co-甲基丙烯酸N,N-二乙基氨乙基酯）阳离子无规共聚物（P（AMA-co-DEAEMA）,简称P）.琼脂糖凝胶电泳实验结果表明聚合物P作为阳离子载体可以有效地络合DNA,通过粒径仪测定的复合物粒子的尺寸在400~600 nm之间.扫描电镜观察的P/DNA复合物形貌是分散均匀的球形颗粒.以25k Da PEI为阳性参照,利用MTT比色法考察了聚合物P对HEK293T细胞的毒性.结果表明,聚合物P的细胞毒性低于25 k Da PEI的细胞毒性.以25 k Da PEI和裸质粒DNA作为参照,我们进一步考察了聚合物P与DNA形成的复合物在HEK293T细胞中的转染效率.结果表明P/DNA复合物在HEK293T细胞中的转染效率远远高于裸质粒DNA的转染效率,并且接近于25 k Da PEI/DNA复合物的转染效率.

关键词：基因载体转染效率细胞毒性原子转移自由基聚合

维普期刊数据库

Wetland and habitat dynamics in the evolving landscape of the Middle Yangtze River Basin

在线全文

学校读者我要写书评

暂无评论

Journal of Geographical Sciences 2025年第1期35卷 88-111页

作者： YANG Peng sun Kaiya ZHU Yanchao xia Jun HUANG Heqing SONG Jingxia SHI xiaorui LU Xixi Hubei Key Laboratory of Regional Ecology and Environmental Change School of Geography and Information Engineering China University of Geosciences Department of Geography National University of Singapore State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University

Wetlands play a critical role in the global environment. The Middle Yangtze River Basin(MYRB), known for its abundant wetland resources, has experienced notable changes resulting from the complex interplay of environmental factors. Therefore, we investigated the spatiotemporal characteristics of wetland ecological quality in the MYRB from 2001 to *** the random forest(RF) regression algorithm and patch-generated land-use simulation(PLUS) model, we forecasted variations in wetland habitat quality and their determinants under the Shared Socioeconomic Pathway-Representative Concentration Pathway(SSPRCP) framework from 2035 to 2095. The main findings are as follows:(1) The RF algorithm was optimal for land-use and land-cover(LULC) classification in the MYRB from 2001 to 2020,when notable changes were observed in water bodies and buildings. However, the forested area exhibited an increase and decrease of 3.9% and 1.2% under the SSP1-2.6 and SSP5-8.5 scenarios, respectively, whereas farmland exhibited a diminishing trend.(2) Wetlands were primarily concentrated in the central and eastern MYRB, with counties in the southwest exhibiting superior ecological-environmental quality from 2001 to 2020. Notably,wetland coverage revealed significantly high level, significant changes, frequent but relatively minor changes under the SSP1-2.6, SSP2-4.5, and SSP 5-8.5 scenarios, respectively.(3)Regions with lower habitat quality were primarily concentrated in urbanized areas characterized by frequent human activities, indicating a clear degradation in habitat quality across different scenarios. In conclusion, we established a foundational framework for future investigations into the eco-hydrological processes and ecosystem quality of watersheds.

关键词：

Dissecting the cell microenvironment of ovarian endometrioma through single-cell RNA sequencing

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Life Sciences 2025年第1期68卷 116-129页

作者： Jiangpeng Wu Siyu xia Wenting Ye Yan sun Jing Cai Fubing Yu Haiping Wen Xiuwei Yi Taikang Li Mingwei Chen Jiayun Chen Ge Song Chuanbin Yang Yali Song Jigang Wang Department of Reproductive Medicine Dongguan Maternal and Child Health Care Hospital Department of Urology and Shenzhen Clinical Research Centre for GeriatricsShenzhen People's HospitalSouthern University of Science and Technology State Key Laboratory for Quality Ensurance and Sustainable Use of Dao-di Herbs Artemisinin Research Centerand Institute of Chinese Materia MedicaChina Academy of Chinese Medical Sciences Reproductive Medicine Center Foshan Women and Children Hospital State Key Laboratory of Antiviral Drugs School of PharmacyHenan University

Ovarian endometrioma（OE）, also known as “chocolate cysts,” is a cystic mass that develops in the ovaries due to endometriosis and is a common gynecological condition characterized by the growth of endometrial tissue outside the uterus, leading to symptoms such as dysmenorrhea, pelvic pain, and infertility. However, the precise molecular and cellular mechanisms driving this pathophysiology remain largely unknown, posing challenges for diagnosis and treatment. Here, we employed integrated single-cell transcriptomic profiling of over 52,000 individual cells from endometrial tissues of OE patients and healthy donors and identified twelve major cell populations. We identified notable alterations in cell type-specific proportions and molecular signatures associated with OE. Notably, the activation of IGFBP5+macrophages with pro-inflammatory properties, NK cell exhaustion, and aberrant proliferation of IQCG+and KLF2+epithelium are key features and may be the potential mechanisms underlying the pathogenesis of OE. Collectively, our data contribute to a better understanding of OE at the single cell level and may pave the way for the development of novel therapeutic strategies.

关键词： ovary high-throughput sequencing transcriptomics gene expression analysis ligand-receptor analysis