检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

榫卯结构弯曲破坏时声发射衰减特性与源定位

北京林业大学学报 2017年第1期39卷 107-111页

作者：赵小矛焦亮亮赵健赵东北京林业大学工学院

由于木结构榫卯接合的部位属于隐藏部位,当其发生损伤时,肉眼无法观测。为了准确地预测榫卯结构的健康状况,可以根据榫卯结构在破坏前,木材所释放出来的声发射能量传播特性进行信息源位置的判定。为此,本研究提出并验证了木材的声发射... 详细信息

由于木结构榫卯接合的部位属于隐藏部位,当其发生损伤时,肉眼无法观测。为了准确地预测榫卯结构的健康状况,可以根据榫卯结构在破坏前,木材所释放出来的声发射能量传播特性进行信息源位置的判定。为此,本研究提出并验证了木材的声发射信号符合能量衰减规律,并且利用能量衰减模型对榫卯结构的声发射源(破坏源)进行定位。首先,采用直径0.5 mm的铅芯为模拟声发射源,探讨了声发射波在木材中的传播和衰减特性,然后进行了榫卯结构弯曲破坏实验,实验中将目标声发射源限定于两个传感器之间,利用两点定位法确定破坏源的位置,经比较计算值与实测值较一致。结果表明:基于AE信号能量衰减模型和两点定位法进行榫卯结构的损伤定位,能得到较准确的破坏源位置,而且外界环境对结果的影响较小。

关键词：榫卯结构声发射能量衰减定位木结构

Modular assembly of complex C-alkyl glycoside enabled via cooperative NHC and photoredox catalysis

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2025年

作者： Rui-Qiang jiao Ming Li Xi Chen Mei-Ze Xu Tian Ding xiao-Ping Gong Zhuo-Mei Li Xue-Yuan Liu Yong-Min liang State Key Laboratory of Applied Organic Chemistry Lanzhou University College of Chemistry and Chemical Engineering Northwest Normal University

C-Alkyl glycosides are found in natural products and are indispensable in drug development programs,owing to their diverse range of medicinal ***-component reactions involving glycosyl radical addition are well documented and proved efficient for the C-alkyl glycosides ***,multicomponent reactions for the rapid and controllable construction of structurally diversified C-alkyl glycosides in a single step remains a significant challenge due to the issues associated with balancing reactivity,compatibility,and ***,we report an NHC and photoredox co-catalyzed three-component method to access complex and valuable C-alkyl *** protocol exhibits broad substrate scope and excellent chemoand ***,nine types of sugars are compatible with this *** addition,the generality of this catalytic strategy was further highlighted by the potential for scalable production,the feasibility of further modifications of the products and its successful application in the late-stage functionalization of pharmaceutical skeletons.

关键词：

基于结构方程模型的羊柴灌丛与沙地土壤间耦合关系

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

北京林业大学学报 2017年第1期39卷 1-8页

作者：王树力梁晓娇马超周健平东北林业大学林学院

为弄清羊柴灌丛与沙地土壤之间的耦合关系,以浑善达克沙地为对象,选择保育状况良好的羊柴种植沙地,构建了样地位置—羊柴灌丛—沙地土壤物理性质—沙地土壤化学性质的结构方程模型。结果表明:沙地恢复15年后,羊柴灌丛的盖度与密度、土... 详细信息

为弄清羊柴灌丛与沙地土壤之间的耦合关系,以浑善达克沙地为对象,选择保育状况良好的羊柴种植沙地,构建了样地位置—羊柴灌丛—沙地土壤物理性质—沙地土壤化学性质的结构方程模型。结果表明:沙地恢复15年后,羊柴灌丛的盖度与密度、土壤物理性质和土壤化学性质均表现出不同程度的空间异质性;羊柴植被的盖度与密度对0~10 cm、10~20 cm、20~40 cm土层土壤的物理性质和化学性质多有正影响,总路径系数分别为0.01、0.42、0.50和-0.07、0.49、0.79;0~10 cm、10~20 cm和20~40 cm土层土壤的物理性质对土壤的化学性质均具有正影响,总路径系数分别为0.80、0.89和1.00;样地位置通过影响羊柴灌丛的盖度与密度而对0~10 cm、10~20 cm和20~40 cm土层的土壤物理性质产生间接影响,间接影响系数分别为-0.01、-0.26和-0.38;样地位置通过影响羊柴灌丛的盖度与密度及土壤物理性质而对0~10 cm、10~20 cm和20~40 cm土层的土壤化学性质产生间接影响,间接影响系数分别为-0.15、-0.02和-0.30;羊柴灌丛的盖度与密度通过影响土壤物理性质而间接影响0~10 cm、10~20 cm和20~40 cm土层的土壤化学性质,间接影响系数分别为0.01、0.37和0.50。沙地植被的生态恢复除自然恢复外,可种植羊柴等沙生灌丛以改善沙地土壤的肥力指标,加快沙地植被的恢复。

关键词：结构方程模型沙地土壤羊柴土壤物理性质土壤化学性质

观察急性脑血栓早期康复护理对降低脑血栓患者致残率的效果观察

在线全文

学校读者我要写书评

暂无评论

按摩与康复医学 2019年第2期10卷 57-59页

作者：梁小娇信宜市人民医院

目的:观察急性脑血栓早期康复护理对降低脑血栓患者致残率的效果。方法:选取本院2015年5月~2017年5月收治的脑血栓患者74例,随机分为对照组和观察组各37例。对照组采用常规护理,观察组在常规护理的基础上实施早期康复护理,观察两组护理... 详细信息

目的:观察急性脑血栓早期康复护理对降低脑血栓患者致残率的效果。方法:选取本院2015年5月~2017年5月收治的脑血栓患者74例,随机分为对照组和观察组各37例。对照组采用常规护理,观察组在常规护理的基础上实施早期康复护理,观察两组护理效果。结果:观察组总有效率、满意度均显著高于对照组(P<0.05);观察组致残率显著低于对照组(P<0.05)。结论:对脑血栓患者实施早期康复护理的临床效果十分显著,其可以有效降低脑血栓患者致残率,提高疗效及满意度,值得临床推广。

关键词：急性脑血栓早期康复护理疗效:致残率:满意度

Advances in the Development of Gradient Scaffolds Made of Nano‑Micromaterials for Musculoskeletal Tissue Regeneration

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2025年第3期17卷 455-500页

作者： Lei Fang xiaoqi Lin Ruian Xu Lu Liu Yu Zhang Feng Tian jiao jiao Li Jiajia Xue Beijing Laboratory of Biomedical Materials Beijing University of Chemical TechnologyBeijing 100029People’s Republic of China State Key Laboratory of Organic‑Inorganic Composites Beijing University of Chemical TechnologyBeijing 100029People’s Republic of China School of Biomedical Engineering Faculty of Engineering and ITUniversity of Technology SydneySydneyNSW 2007Australia

The intricate hierarchical structure of musculoskeletal tissues,including bone and interface tissues,necessitates the use of complex scaffold designs and material structures to serve as tissue-engineered *** has led to growing interest in the development of gradient bone scaffolds with hierarchical structures mimicking the extracellular matrix of native tissues to achieve improved therapeutic *** on the anatomical characteristics of bone and interfacial tissues,this review provides a summary of current strategies used to design and fabricate biomimetic gradient scaffolds for repairing musculoskeletal tissues,specifically focusing on methods used to construct compositional and structural gradients within the *** latest applications of gradient scaffolds for the regeneration of bone,osteochondral,and tendon-to-bone interfaces are ***,the current progress of testing gradient scaffolds in physiologically relevant animal models of skeletal repair is discussed,as well as the challenges and prospects of moving these scaffolds into clinical application for treating musculoskeletal injuries.

关键词： Gradient scaffolds Musculoskeletal tissues Advanced manufacturing Biomaterials Tissue regeneration

The autophagy-lysosome pathway:a potential target in the chemical and gene therapeutic strategies for Parkinson’s disease

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第1期20卷 139-158页

作者： Fengjuan jiao Lingyan Meng Kang Du Xuezhi Li School of Mental Health Jining Medical UniversityJiningShandong ProvinceChina Shandong Collaborative Innovation Center for Diagnosis Treatment and Behavioral Interventions of Mental DisordersInstitute of Mental HealthJining Medical UniversityJiningShandong ProvinceChina

Parkinson’s disease is a common neurodegenerative disease with movement disorders associated with the intracytoplasmic deposition of aggregate proteins such asα-synuclein in *** one of the major intracellular degradation pathways,the autophagy-lysosome pathway plays an important role in eliminating these *** evidence has shown that upregulation of the autophagy-lysosome pathway may contribute to the clearance ofα-synuclein aggregates and protect against degeneration of dopaminergic neurons in Parkinson’s ***,multiple genes associated with the pathogenesis of Parkinson’s disease are intimately linked to alterations in the autophagy-lysosome ***,this pathway appears to be a promising therapeutic target for treatment of Parkinson’s *** this review,we briefly introduce the machinery of ***,we provide a description of the effects of Parkinson’s disease–related genes on the autophagy-lysosome ***,we highlight the potential chemical and genetic therapeutic strategies targeting the autophagy–lysosome pathway and their applications in Parkinson’s disease.

关键词： autophagy chemical therapy gene therapy Parkinson’s disease α-synuclein

不同蛋白水平日粮对澳洲白育成羊生长性能和粪尿排泄指标的影响

在线全文

学校读者我要写书评

暂无评论

饲料研究 2023年第22期46卷 1-7页

作者：梁晓姣刘志成邱淑春张玉内蒙古农业大学内蒙古呼和浩特010018

试验旨在研究不同蛋白水平对澳洲白育成羊生长性能、代谢指标以及减排效益的影响。选取生长状态相似、体重(40.03±0.21) kg、健康状态良好的澳洲白育成羊24只,随机分为4组,每组6个重复,每个重复1只羊。对照组育成羊饲喂普通蛋白水平日... 详细信息

试验旨在研究不同蛋白水平对澳洲白育成羊生长性能、代谢指标以及减排效益的影响。选取生长状态相似、体重(40.03±0.21) kg、健康状态良好的澳洲白育成羊24只,随机分为4组,每组6个重复,每个重复1只羊。对照组育成羊饲喂普通蛋白水平日粮(12.07%),试验Ⅰ组育成羊饲喂标准蛋白减少1%的日粮,试验Ⅱ组育成羊饲喂标准蛋白减少2%的日粮,试验Ⅲ组育成羊饲喂为标准蛋白减少4%的日粮。预试期10 d,正式试验期30 d。结果表明,试验10~20 d,试验Ⅰ组育成羊平均增重最高。试验30 d,试验组育成羊粪铜、尿砷减少幅度最大,试验Ⅱ组羊粪氮、粪磷、粪铬、尿氮、尿磷、尿铜减少幅度最大,试验Ⅲ组羊粪锌、粪镉、粪砷、尿锌减少幅度最大。研究表明,澳洲白育成羊饲喂标准蛋白减少2%的日粮在不影响生长指标情况下,可以减少氮磷以及重金属的排放,降低环境污染。

关键词：澳洲白育成羊粗蛋白水平体尺指标粪尿指标

富硒蚯蚓粉对芦丁鸡产蛋性能、蛋品质、硒沉积及抗氧化功能的影响

在线全文

学校读者我要写书评

暂无评论

饲料研究 2023年第13期46卷 38-43页

作者：刘志成梁晓姣邱淑春张玉内蒙古农业大学动物科学学院内蒙古呼和浩特010018

试验旨在探究日粮中添加富硒蚯蚓粉对芦丁鸡产蛋性能、蛋品质及组织硒沉积的影响。试验选用160只体重接近、健康状态良好的芦丁鸡,随机分成4组,每组4个重复,每个重复10只鸡。LJ0组(对照组)芦丁鸡饲喂基础日粮,LJ1组、LJ2组、LJ3组分别... 详细信息

试验旨在探究日粮中添加富硒蚯蚓粉对芦丁鸡产蛋性能、蛋品质及组织硒沉积的影响。试验选用160只体重接近、健康状态良好的芦丁鸡,随机分成4组,每组4个重复,每个重复10只鸡。LJ0组(对照组)芦丁鸡饲喂基础日粮,LJ1组、LJ2组、LJ3组分别在基础日粮中添加0.5%、1.0%、2.0%富硒蚯蚓粉(硒含量为112 mg/kg)。预试期7d,正式试验期28 d。结果显示,与LJ0组相比,各试验组芦丁鸡的平均蛋重、产蛋率显著增加(P0.05)。与LJ0组相比,各试验组鸡蛋和肌肉中的总硒、无机硒和有机硒含量均极显著提高(P<0.01);鸡蛋中谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)的活性和总抗氧化能力(T-AOC)极显著提高(P<0.01),丙二醛(MDA)含量极显著降低(P<0.01)。研究表明,在芦丁鸡日粮中添加1.0%富硒蚯蚓粉效果较好,能够在一定程度上提升芦丁鸡产蛋性能、鸡蛋抗氧化性性能以及组织硒沉积。

关键词：硒蚯蚓粉芦丁鸡产蛋性能蛋品质硒沉积抗氧化

Meta-analysis of the Occurrence Characteristics and Influencing Factors of Microplastics in Agricultural Soil in China

在线全文

学校读者我要写书评

暂无评论

Huanjing Kexue/Environmental Science 2025年第1期46卷 498-509页

作者： Wu, Ting jiao, Yang-Yang jiao, Hai-Hua School of Life Science Shanxi Normal University Taiyuan 030032 China Department of Life Sciences Changzhi University Changzhi 046011 China Henan Institute of Advanced Technology Zhengzhou University Zhengzhou 450003 China

The potential threat of soil microplastics（MPs，particle sizes smaller than 5 mm）to the agricultural environment and food security production has become a hot issue，but there are few systematic studies on the characteristics and influencing factors of MP pollution in agricultural soil in China. Based on the data of soil MPs and related environmental factors（temperature，precipitation，soil pH，and organic carbon）and social and economic factors（permanent population，gross regional product per capita，gross industrial product per capita，and cultivated land area per capita）extracted from 6 694 samples from 85 published studies from 2020 to 2023，meta-analysis was performed. The characteristics of MPs pollution in agricultural soil and the key factors affecting the accumulation of MPs in soil in six administrative regions of China were analyzed. The results showed that soil MPs had six colors：（semi-）transparent，black，white，yellow，blue，green，and red. There were five kinds of shapes：fragment，fiber，film，particle，and foam. The particle size was between 0.01 and 5.0 mm. There were nine types of MPs：polyethylene（PE），polypropylene（PP），polystyrene（PS），polyester（PES），polyethylene terephthalate（PET），polyvinyl chloride （PVC），rayon（RY），polyacrylonitrile（PAN），and polyamide（PA）. The abundance gradient of soil MPs in different regions was as follows：South-central region > Northwest region > Southwest region > East China region > North China region > Northeast region. The（semi-）transparent（27.6%），fragmented（32.2%），0.01~0.5 mm（66.3%），and PE （37%）types of MPs had the highest detection rates. The characteristics of soil MPs are the result of natural environmental factors（temperature，precipitation，soil pH，organic carbon）and social factors（permanent population，gross regional product per capita，gross industrial product per capita，cultivated land area per capita）. © 2025 Science Press. All rights reserved.

关键词： Polyvinyl chlorides