检索结果-南通市图书馆

高海拔隧道喷浆出碴过程风速场及粉尘分布规律数值模拟研究

在线全文

学校读者我要写书评

暂无评论

隧道建设（中英文） 2024年第6期44卷 1241-1250页

作者：马国栋黄嘉洵王栋尹龙周川川张江石中铁隧道局集团(上海)特种高新技术有限公司上海201306 中国矿业大学(北京)应急管理与安全工程学院北京100083 中铁隧道局集团有限公司广东广州511458

为明确气压等环境参数对粉尘运移的影响,掌握高海拔隧道空间重点产尘工序粉尘质量浓度分布,使用Fluent软件模拟隧道喷浆和出碴阶段风速场和粉尘质量浓度场,分析海拔对隧道空间内风流和粉尘质量浓度波动性的影响。通过曲线拟合风速场和... 详细信息

为明确气压等环境参数对粉尘运移的影响,掌握高海拔隧道空间重点产尘工序粉尘质量浓度分布,使用Fluent软件模拟隧道喷浆和出碴阶段风速场和粉尘质量浓度场,分析海拔对隧道空间内风流和粉尘质量浓度波动性的影响。通过曲线拟合风速场和粉尘质量浓度场的沿程分布,建立隧道粉尘质量浓度预测模型。引入风速不均匀度和粉尘质量浓度不均匀度参数,构建海拔与风速、粉尘质量浓度不均匀度的线性回归方程。研究结果表明:1)高海拔地区隧道通风过程中,粉尘运移速度接近风速所用时间相比平原地区较长;低海拔地区风流接近直线沿全断面流出隧道,随着海拔升高,风流覆盖范围逐渐缩小,风流在水平方向逐渐沿S型流出隧道。2)喷浆过程中,距掌子面40 m以内风速较高,40 m以外风速迅速下降,在距掌子面60~180 m均匀波动;隧道整体粉尘质量浓度随海拔上升而发生波动性变化,在距掌子面20~180 m均匀下降,呈近似线性降低。3)出碴过程中,海拔上升,断面平均风速和呼吸面平均粉尘质量浓度值无明显变化,风速不均匀度和粉尘质量浓度不均匀度逐渐呈线性升高;海拔每上升1 000 m,风速不均匀度上升0.156 m^(2)/s^(2),粉尘质量浓度不均匀度上升4.42×10^(-6)kg/m^(3)。

关键词：高海拔隧道压入式通风喷浆出碴风速场粉尘运移数值模拟

A SSLE-TYPE ALGORITHM OF QUASI-STRONGLY SUB-FEASIBLE DIRECTIONS FOR INEQUALITY CONSTRAINED MINImaX PROBLEMS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational mathematics 2023年第1期41卷 133-152页

作者： Jinbao Jian guodong ma Yufeng Zhang College of mathematics and Physics Guangxi Key Laboratory of Hybrid Computation and IC Design AnalysisCenter for Applied Mathematics and Artificial IntelligenceGuangxi University for NationalitiesNanning 530006China School of mathematics and Information Science Guangxi UniversityNanning 530004China

In this paper,we discuss the nonlinear minimax problems with inequality *** on the stationary conditions of the discussed problems,we propose a sequential systems of linear equations(SSLE)-type algorithm of quasi-strongly sub-feasible directions with an arbitrary initial iteration *** means of the new working set,we develop a new technique for constructing the sub-matrix in the lower right corner of the coefficient matrix of the system of linear equations(SLE).At each iteration,two systems of linear equations(SLEs)with the same uniformly nonsingular coefficient matrix are *** mild conditions,the proposed algorithm possesses global and strong ***,some preliminary numerical experiments are reported.

关键词： Inequality constraints Minimax problems Method of quasi-strongly subfeasible directions SSLE-type algorithm Global and strong convergence

基于GEE和Canoco的沙丘移动速率及其内外控制因子贡献率分析

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

中国水土保持科学 2024年第3期22卷 93-99页

作者：王军川逄红王瑞霞马国栋靳磊张萍宁夏大学林业与草业学院银川750021 海原县自然资源局宁夏海原755200 内蒙古自治区水利科学研究院呼和浩特010050 宁夏灵武白芨滩国家级自然保护区管理局宁夏灵武751400

环境因子控制沙丘移动速率的研究多集中于定性分析和一对一定量分析层面。基于高分辨率遥感影像分析2008—2021年间宁夏白芨滩流动沙丘在7个时段的移动速率,利用GEE获取研究区各时段的多个环境因子数值,再采用Canoco的冗余分析揭示各环... 详细信息

环境因子控制沙丘移动速率的研究多集中于定性分析和一对一定量分析层面。基于高分辨率遥感影像分析2008—2021年间宁夏白芨滩流动沙丘在7个时段的移动速率,利用GEE获取研究区各时段的多个环境因子数值,再采用Canoco的冗余分析揭示各环境因子对沙丘移动速率的贡献率。结果表明:1)2008—2021年间,流动沙丘脊线数逐步减少而脊线平均长度递增,沙丘在移动中发生合并,沙丘移动速率分5个阶段稳步下降,每个阶段的降速在0.22~0.28 m/a间,13 a间共下降约1 m/a;2)内控因子沙丘高度和宽度与移动速率均呈极显著线性负相关关系,缺陷密度与其呈极显著线性正相关关系(P<0.01);外控因子合成输沙势(RDP)、植被覆盖度、累积降水量、平均地温(LST)、平均气温对沙丘移动的贡献率分别为78.7%、6.7%、3.9%、2.7%和2.6%,RDP是控制白芨滩流动沙丘近13年来移动速率的主要外因,但对比2个时段发现季节性冻结期内LST是控制沙丘移动的另一关键因子。

关键词：沙丘移动合成输沙势环境因子贡献率

达格列净治疗老年2型糖尿病合并射血分数下降心力衰竭患者的效果

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

内科 2024年第3期19卷 237-241页

作者：张法宁陈曼杨马国栋广东省惠州市第一人民医院老年医学科惠州市516003

目的探讨达格列净治疗老年2型糖尿病合并射血分数下降心力衰竭(HFrEF)患者的效果。方法选取80例老年2型糖尿病合并HFrEF患者作为研究对象,随机将其分为达格列净组和对照组,每组40例。对照组行标准化常规治疗,达格列净组在对照组的基础... 详细信息

目的探讨达格列净治疗老年2型糖尿病合并射血分数下降心力衰竭(HFrEF)患者的效果。方法选取80例老年2型糖尿病合并HFrEF患者作为研究对象,随机将其分为达格列净组和对照组,每组40例。对照组行标准化常规治疗,达格列净组在对照组的基础上加用达格列净,两组均治疗6个月。比较两组患者疗效,治疗前和治疗6个月后实验室指标、心脏彩超指标、6 min步行试验距离、健康调查简表(SF-36)评分,以及治疗期间再住院率和不良反应发生情况。结果达格列净组患者治疗总有效率高于对照组(95.00%比80.00%,P0.05),治疗6个月后两组患者FBG、2hPBG、HbA1c、NT-proBNP水平、LVEDd、LVESd均下降,且达格列净组患者上述指标水平均低于对照组;两组LVEF、6 min步行试验距离、SF-36评分均提高/延长,且达格列净组患者LVEF、6 min步行试验距离、SF-36评分均长/高于对照组(均P<0.05)。治疗过程中,达格列净组再住院率(7.50%)低于对照组(30.00%)(χ^(2)=6.646,P=0.010);两组均未出现严重的不良反应。结论在标准化治疗的基础上给予老年2型糖尿病合并HFrEF患者达格列净治疗可显著改善心力衰竭,控制血糖水平,降低再住院率,促进患者生活质量的提高。

关键词：达格列净 2型糖尿病射血分数下降心力衰竭

Effects of baffle position in serpentine flow channel on the performance of proton exchange membrane fuel cells

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2024年第5期69卷 250-262页

作者： guodong Xia Xiaoya Zhang Dandan ma MOE Key Laboratory of Enhanced Heat Transfer and Energy Conservation Beijing Key Laboratory of Heat Transfer and Energy ConversionBeijing University of TechnologyBeijing 100124China

This study used a three-dimensional numerical model of a proton exchange membrane fuel cell with five types of channels:a smooth channel(Case 1);eight rectangular baffles were arranged in the upstream(Case 2),midstream(Case 3),downstream(Case 4),and the entire cathode flow channel(Case 5)to study the effects of baffle position on mass transport,power density,net power,***,the effects of back pressure and humidity on the voltage were *** showed that compared to smooth channels,the oxygen and water transport facilitation at the diffusion layer-channel interface were added 11.53%-20.60%and 7.81%-9.80%at 1.68 A·cm^(-2)by adding *** closer the baffles were to upstream,the higher the total oxygen flux,but the lower the flux uniformity the worse the water *** oxygen flux of upstream baffles was 8.14%higher than that of downstream baffles,but oxygen flux uniformity decreased by 18.96%at 1.68 A·cm^(-2).The order of water removal and voltage improvement was Case 4>Case 5>Case 3>Case 2>Case *** power of Case 4 was 9.87%higher than that of the smooth *** the Case 4,when the cell worked under low back pressure or high humidity,the voltage increments were *** potential increment for the back pressure of 0 atm was 0.9%higher than that of 2 atm(1 atm=101.325 kPa).The potential increment for the humidity of 100%was 7.89%higher than that of 50%.

关键词： Proton exchange membrane fuel cell Baffle position mass transfer Net power Uniformity Voltage increment

富血小板血浆治疗早中期膝关节骨性关节炎的研究进展

在线全文

学校读者我要写书评

暂无评论

内蒙古医学杂志 2024年第6期56卷 715-718,722页

作者：马国栋胡建锋王永强甘肃中医药大学兰州730000 天水市中医医院甘肃天水741000

膝关节骨性关节炎(knee osteoarthritis,KOA)作为一种临床常见的退行性疾病,其特征是膝关节软骨变性和反应性增生,发病人群中老年人占比最高。由于本病的主要临床特征为膝关节疼痛、关节肿胀、活动受限和畸形,在降低患者生活质量的同时... 详细信息

膝关节骨性关节炎(knee osteoarthritis,KOA)作为一种临床常见的退行性疾病,其特征是膝关节软骨变性和反应性增生,发病人群中老年人占比最高。由于本病的主要临床特征为膝关节疼痛、关节肿胀、活动受限和畸形,在降低患者生活质量的同时,给患者带来了严重的疼痛和经济负担,故应采取何种治疗方法缓解其临床症状、延缓疾病进展已成为当前亟待解决的问题。富血小板血浆(platelet-rich plasma,PRP)作为一种自身血浆提取物,可通过促进软骨细胞修复、促进细胞外基质合成、调控膝关节腔内微环境等方式,延缓膝关节组织退变,减轻疼痛,改善膝关节活动功能。本文通过总结PRP的制备、分类、治疗机制、实验研究及临床研究进展等方面,为进一步治疗中早期KOA提供临床思路。

关键词：膝关节骨性关节炎富血小板血浆生长因子

白介素-1β调控膝骨性关节炎作用的研究进展

在线全文

学校读者我要写书评

暂无评论

内蒙古医学杂志 2024年第6期56卷 704-707页

作者：王永强胡建锋马国栋甘肃中医药大学兰州730000 天水市中医医院甘肃天水741000

膝骨性关节炎(knee osteoarthritis,KOA)的发生发展是一个缓慢性、渐进性的过程,其中关节软骨的破坏、滑膜炎的产生是不可避免的。白介素-1β(interleukin-1β,IL-1β)作为一种促炎细胞因子,主要由巨噬细胞、T/B细胞、单核细胞及淋巴细... 详细信息

膝骨性关节炎(knee osteoarthritis,KOA)的发生发展是一个缓慢性、渐进性的过程,其中关节软骨的破坏、滑膜炎的产生是不可避免的。白介素-1β(interleukin-1β,IL-1β)作为一种促炎细胞因子,主要由巨噬细胞、T/B细胞、单核细胞及淋巴细胞分泌产生,其参与各种炎症性疾病的发病机制,如强直性脊柱炎(AS)、类风湿性关节炎(RA)。本文通过文献综述总结IL-1β在KOA中的相关作用机制,发现IL-1β在KOA中调控软骨细胞、滑膜炎相关信号通路、蛋白及基因表达来减弱软骨细胞的分化、加快软骨细胞的坏死及促进滑膜炎症反应而加快KOA的进展,为进一步认识KOA的发病机制提供一定的理论依据,为深层次的临床研究提供新思路。

关键词：膝骨性关节炎白介素-1β 软骨细胞滑膜细胞

The current trend and challenges of developing red yeast rice-based food supplements for hypercholesterolemia

在线全文

学校读者我要写书评

暂无评论

未来食品学报(英文) 2023年第4期3卷 312-329页

作者： Gong Chen Wanbo Chen Jinhong Xu guodong ma Xinge Hu Guoxun Chen Department of Internal Medicine University of Texas Southwestern Medical Center at DallasDallas 75390USA Clinical School of Chinese Medicine Hubei University of Chinese MedicineWuhan 430022China College of Pharmacy South-Central University for NationalitiesWuhan 430074China Department of Nutrition University of Tennessee at KnoxvilleKnoxville 37996USA

Hypercholesterolemia is a risk factor of cardiovascular diseases,which have been managed using statin *** yeast rice(RYR)as a traditional food in the Eastern Asia countries has anti-hyperlipidemia ***,a variety of food supplement products containing RYR have been developed to lower blood cholesterol,which is attributed to the presence of monacolins,especially monacolin K(lovastatin,a statin drug).This review was aimed to summarize the clinical trials using RYR products to investigate their effects on lipid profiles in *** articles of human clinical trials were retrieved from PubMed and discussed *** showed that RYR and its extracts have been included in commercially available products alone and in combinations with various other materials,which include bioactive compounds such as coenzyme Q10 and berberine,vitamins,extracts from other plants such as phytosterols,polyunsaturated fatty acids or even *** durations of the trials ranged from 4 weeks to 60 *** content of monacolin K ranged from 0.32 mg/pack to 10 mg/*** data of these human clinical trials demonstrated that these RYR supplement products were sufficient to reduce blood cholesterol in different ***,the inclusions of certain materials might not have additive ***,studies including a lovastatin only positive control group with the equivalent dose as that of monacolin K in the RYR products remain to be ***,variations of monacolin K contents and presence of toxic citrinin are still ***,bioactivities of other components in RYR should be investigated as *** future studies will certainly help to fully explore the potentials of this traditional food in the combat against cardiovascular and other metabolic diseases.

关键词： Cardiovascular diseases Cholesterol Human clinical trials Food supplement Hypercholesterolemia Monacolins Red yeast rice

Enhancing multifunctional photocatalysis with acetate-assisted cesium doping and unlocking the potential of Z-scheme solar water splitting

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Carbon Energy 2024年第3期6卷 178-195页

作者： Mengmeng ma Jingzhen Li Xiaogang Zhu Kong Liu Kaige Huang guodong Yuan Shizhong Yue Zhijie Wang Shengchun Qu Key Laboratory of Semiconductor materials Science Beijing Key Laboratory of Low Dimensional Semiconductor Materials and DevicesInstitute of SemiconductorsChinese Academy of SciencesBeijingChina Center of materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijingChina Department of Physics College of Physical Science and TechnologyXiamen UniversityXiamenChina State Key Laboratory for Superlattices and Microstructures Institute of SemiconductorsChinese Academy of SciencesBeijingChina

Graphitic carbon nitride(g-C_(3)N_(4))has been extensively doped with alkali metals to enlarge photocatalytic output,in which cesium(Cs)doping is predicted to be the most ***,the sluggish diffusion and doping kinetics of precursors with high melting points,along with imprecise regulation,have raised the debate on whether Cs doping could make *** this matter,we attempt to confirm the positive effects of Cs doping on multifunctional photocatalysis by first using cesium acetate with the character of easy *** optimized Csdoped g-C_(3)N_(4)(CCN)shows a 41.6-fold increase in visible-light-driven hydrogen evolution reaction(HER)compared to pure g-C_(3)N_(4) and impressive degradation capability,especially with 77%refractory tetracycline and almost 100%rhodamine B degradedwithin an *** penetration ofCs+is demonstrated to be a mode of interlayer doping,and Cs–N bonds(especially with sp^(2) pyridine N in C═N–C),along with robust chemical interaction and electron exchange,are *** atomic configuration triggers the broadened spectral response,the improved charge migration,and the activated photocatalytic ***,we evaluate the CCN/cadmium sulfide hybrid as a Z-scheme configuration,promoting the visible HER yield to 9.02 mmol g^(−1) h^(−1),which is the highest ever reported among all CCN *** work adds to the rapidly expanding field of manipulation strategies and supports further development of mediating served for photocatalysis.

关键词： acetate-assisted cesium doping multifunctional photocatalysis Z-scheme