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Experimental and numerical investigations on acoustic damping of monoclinic crystalline wideband sound absorbing structures

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Journal of Central South University 2024年第6期31卷 1931-1944页

作者： XIE Su-chao HE Lei yan hong-yu ZHANG Feng-yi HE Guan-di WANG Jia-cheng Key Laboratory of Traffic Safety on Track Ministry of EducationSchool of Traffic&Transportation EngineeringCentral South UniversityChangsha 410075China Joint International Research Laboratory of Key Technology for Rail Traffic Safety Changsha 410075China National&Local Joint Engineering Research Center of Safety Technology for Rail Vehicle Changsha 410075China

In order to overcome the limitations of traditional microperforated plate with narrow sound absorption bandwidth and a single structure,two multi-cavity composite sound-absorbing materials were designed based on the shape of monoclinic crystals:uniaxial oblique structure(UOS)and biaxial oblique structure(BOS).Through finite element simulation and experimental research,the theoretical models of UOS and BOS were verified,and their sound absorption mechanisms were *** the same time,the influence of multi-cavity composites on sound absorption performance was analyzed based on the theoretical model,and the influence of structural parameters on sound absorption performance was *** research results show that,in the range of 100-2000 Hz,UOS has three sound absorption peaks and BOS has five sound absorption *** frequency range of the half-absorption bandwidth(α>0.5)of UOS and BOS increases by 242% and 229%,*** with traditional microperforated sound-absorbing structures,the series and parallel hybrid methods significantly increase the sound-absorbing bandwidth of the sound-absorbing *** research has guiding significance for noise control and has broad application prospects in the fields of transportation,construction,and mechanical design.

关键词： monoclinic crystal microperforated plate acoustic metamaterials inclined cavity sound absorption

马齿苋多糖摄入对老龄大鼠肠道菌群结构的影响

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营养学报 2024年第3期46卷 276-282页

作者：黄小流罗辉龙书瑾姜慧张杏颜红宇黄玉珊井冈山大学医学部吉安343009 井冈山大学医务所吉安343009 赣南医学院第一附属医院赣州341000

目的探究马齿苋多糖(Portulacaoleraceapolysaccharide,POP)对老龄大鼠肠道菌群结构的影响。方法20只SD老龄大鼠(21月龄)随机分为2组,每组10只。对照组(Con)大鼠饲喂实验鼠维持颗粒料,干预组(POP)大鼠饲喂添加1.0%POP维持颗粒料,自由摄... 详细信息

目的探究马齿苋多糖(Portulacaoleraceapolysaccharide,POP)对老龄大鼠肠道菌群结构的影响。方法20只SD老龄大鼠(21月龄)随机分为2组,每组10只。对照组(Con)大鼠饲喂实验鼠维持颗粒料,干预组(POP)大鼠饲喂添加1.0%POP维持颗粒料,自由摄食和饮水,持续15 w。实验结束后,采用16S rRNA高通量测序技术分析肠道菌群结构。结果两组共有6087个相同的操作分类单元(OTUs),Con组有1025个特征OTUs,POP组有1131个特征OTUs。两组动物肠道菌群有相似的α多样性,组间β多样性有显著性差异。摄入POP后,老龄大鼠肠道菌群中的梭杆菌门(Fusobacteria)、乳杆菌属(Lactobacillus)、瘤胃梭菌属(Ruminiclostridium_9)、Intestinimonas菌属、粪杆菌属(Faecalibacterium)、脱硫弧菌属(Desulfovibrio)、嗜果胶拟杆菌属([Bacteroides]_pectinophilus_group)和瘤胃梭菌(Ruminiclostridium)相对丰度显著降低,而副拟杆菌属(Parabacteroides)、瘤胃菌科(Ruminococcaceae_UCG-005)和Marvinbryantia菌属相对丰度显著增加。老龄大鼠摄入POP后可能上调细胞过程、新陈代谢和生物系统相关基因的表达,下调环境信息处理、人类疾病和遗传信息处理等相关基因的表达。结论POP可影响老龄大鼠肠道菌群结构,瘤胃菌科(Ruminococcaceae_UCG.005)和副拟杆菌属(Parabacteroides)是主要的生物标志物。

关键词：马齿苋多糖肠道菌群老龄大鼠

Comparison of 1.5% lidocaine and 0.5% ropivacaine epidural anesthesia combined with propofol general anesthesia guided by bispectral index

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2007年第6期8卷 428-434页

作者： XIANG yan LI yu-hong Department of Anesthesiology the First Affiliated Hospital School of Medicine Zhejiang University Hangzhou 310003 China

Objective： To compare the effects of epidural anesthesia with 1.5% lidocaine and 0.5% ropivacaine on propofol requirements, the time to loss of consciousness （LOC）, effect-site propofol concentrations, and the hemodynamic variables during induction of general anesthesia guided by bispectral index （BIS） were studied. Methods： Forty-five patients were divided into three groups to receive epidurally administered saline （Group S）, 1.5% （w/w） lidocaine （Group L）, or 0,5% （w/w） ropivacaine （Group R） Propofol infusion was started to produce blood concentration of 4 lag/ml. Once the BIS value reached 40-50, endotracheal intubation was facilitated by 0.1 mg/kg vecuronium. Measurements included the time to LOC, effect-site propofol concentrations, total propofol dose, mean arterial blood pressure （MABP）, and heart rate （HR） at different study time points. Results： During induction of anesthesia, both Groups L and R were similar for the time to LOC, effect-site propofol concentrations, total propofol dose, MABP, HR, and BIS. The total doses of propofol administered until 1 min post-intubation were significantly less in patients of Groups R and L compared with Group S. MABP and HR were significantly lower following propofol induction compared with baseline values in the three groups, or MABP was significantly increased following intubation as compared with that prior to intubation in Group S but not in Groups R and L while HR was significantly increased following intubation in the three groups. Conclusion： Epidural anesthesia with 1.5% lidocaine and 0.5% ropivacaine has similar effects on the time to LOC, effect-site propofol concentrations, total propofol dose, and the hemodynamic variables during induction of general anesthesia.

关键词： Propofol Lidocaine Ropivacaine Epidural anethesia Bispectral index

1980—2020年郑州大都市区“三生”功能演化特征及其优化路径

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湖北农业科学 2024年第6期63卷 66-74,115页

作者：贾琦尹泽凯张超玉刘毅洁燕宏宇郑州轻工业大学艺术设计学院郑州450002 山东建筑大学艺术学院济南250101

研究聚焦郑州大都市区1980—2020年“三生”功能的演化特征,以土地利用分类数据为依据,采用GIS空间探索性分析法测度郑州大都市区“三生”功能特征,并分类提出优化调控策略。结果表明,郑州大都市区的生产和生态功能持续下降,以郑州主城... 详细信息

研究聚焦郑州大都市区1980—2020年“三生”功能的演化特征,以土地利用分类数据为依据,采用GIS空间探索性分析法测度郑州大都市区“三生”功能特征,并分类提出优化调控策略。结果表明,郑州大都市区的生产和生态功能持续下降,以郑州主城区为中心的生活功能则快速扩张;都市区生产功能持续东移,生活功能不断聚集在各地市建成区周边,生态功能集中在西部山区和黄河沿线,呈分散和破碎化趋势;郑州大都市区“三生”功能综合水平较高区域多位于由荥阳—新郑—中牟围合而成的区域,且不断向核心区域集聚,指标呈提升趋势。遵循提升复合型功能用地占比,适当扩大生活功能用地,集约利用生产功能用地并加强产城融合功能,科学布局“三生”功能的数量占比等原则,提出了“三生”功能在空间分配上的均衡性布局策略,以期促进郑州大都市区国土空间的可持续利用。

关键词： “三生”功能综合功能水平优化路径郑州大都市区

The amount effect of catalyst on the urethane reaction of o-hydroxybenzyl alcohol

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Chinese Chemical Letters 2012年第2期23卷 241-244页

作者： Peng Fei yang yan hong yu Shun Ping Wang Tian Duo Li Shandong Provincial Key Laboratory of Fine Chemicals Shandong Polytechnic UniversityJinan 250353China School of Business Shandong Polytechnic UniversityJinan 250353China

The urethane reaction of o-hydroxybenzyl alcohol with phenyl isocyanate was monitored with in situ *** dilaurate was used as catalyst and its amount effect was *** was found that there was an obvious induction period before reaction *** was interesting that the time of induction period climbed up and then declined with the increase of dibutyltin dilaurate. When the concentration of dibutyltin dilaurate reached 9.58×10^（-5） mol/L,the induction period disappeared completely and hereafter did not appear any ***,the urethane reaction kinetics was *** the concentration of dibutyltin dilaurate increased,the reaction rate of phenolic group（k_1） increased sharply,but the reaction rate of alcoholic group（k_2） appeared of little change on the whole.k_1 increased about 20-fold,yet k_2 increased about 2-fold when the concentration of dibutyltin dilaurate varied from 9.58×10^（-6） mol/L to 1.92×10~4 mol/L,which made the value of k_1/k_2 enlarge.

关键词： Urethane reaction FT-IR Dibutyltin dilaurate Polymerization

Study of concentration of amniotic fluid Alpha-fetal protein in thalassemia fetus

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Asian Pacific Journal of Tropical Medicine 2017年第2期10卷 192-194页

作者： Yi Ling yan-hong yu Song Jin Chun-Xia Hu Wei Peng hong-yu Zhang Huo Fu Ning Zhang yan-Xin Wei Ze-Jun Chen Department of Obstetrics and Gynecology Souther HospitalAffiliated Hospital of Southern Medical University Department of Obstetrics Prenatal Diagnose CenterAffiliated Hospital of Hainan Medical University

Objective:To test the hypothesis that concentration of amniotic fluid alpha-fetal protein(AFAFP) is increased in thalassemia ***:A total of 135 cases of amniocentesis admitted from July 2013 to December 2014 were included in this *** them 98 cases of normal fetuses were assigned into control group and 37 cases of thalassemia fetus were included as thalassemia fetus ***-fetoprotein levels detected by enzyme linked immunosorbent assay and the alpha-fetoprotein concentration were compared between the two *** is no significant difference in gestrational age between the two ***:*** concentration in thalassemia fetus group was significantly higher than that of normal control group [(1541.65±734.78) μg/mL vs.(2728.84± 1539.97) μg/mL ],and amniotic fluid AFP concentration was related to fetal *** concentration in pureα-thalassemia fetus was higher than that of β thalassemia fetus or mixed αand was not ***:Concentration of a β thalassemia fetus,but the difference mniotic fluid alpha-fetal protein is increased in thalassemia *** concentration inα-thalassemia fetus was higher than that of β thalassemia or mixed αand lore β thalassemia fetus but difference was not *** studies are needed to exp the possible correlation between Down syndrome and biochemical markers of Thalassemia.

关键词： Alpha-fetoprotein Amniotic fluid Thalassemia Fetus

Research on Bast Fiber Extracted from the White Bark of Three Species in the Genus Broussonetia

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Chinese Journal of Polymer Science 2024年第6期42卷 729-738页

作者： Shan-Shan Jin Si-Nong Wang yan-yan Huang Jing-yu Zhang Peng Liu Hui yu hong-Dong Zhang yu-Liang yang Institute for Preservation and Conservation of Chinese Ancient Books Fudan University LibraryFudan UniversityShanghai200433China State key laboratory of Molecular Engineering of polymers Department of Macromolecular ScienceFudan UniversityShanghai200433China

Against the backdrop of a global paper resource shortage,there is a growing need to identify fast-growing tree species capable of producing long-lasting *** plant species namely Broussonetia kazinoki,Broussonetia papyrifera and hybrid paper mulberry,belong to the Broussonetia genus,were collected from China to study their white bark suitability for pulp and *** chemical composition revealed that the holocellulose content in Broussonetia kazinoki and Broussonetia papyrifera was more than 80%.The molecular weight distribution of several holocellulose/α-cellulose is observed by GPC,which allows us to better observe the changes of various components on the molecular *** yield,lignin,whiteness,and molecular weight of the pulps obtained by NaOH treatment were *** microscope was used to characterize the fiber length-width ratio and ***,the improvement of the fiber rigidity method based on the Kratky-Porod chain model makes it more theoretical and further reveals the influencing factors of fiber *** study demonstrates the high potentiality of these three species for papermaking applications.

关键词： Broussonetia genus Cellulose Alkaline pulping Kratky-Porod chain model Fiber rigidity

Analgesic and anti-inflammatory activity of Cotinus coggygria *** in vivo

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Asian Pacific Journal of Tropical Biomedicine 2024年第6期14卷 225-235页

作者： Kai Lu Chong-yu yang Zhao-hong yan Department of Anesthesiology Qiantang Campus Sir Run Run Shaw HospitalSchool of MedicineZhejiang UniversityHangzhou310018China Department of Anesthesiology 3201 HospitalHanzhong723000China Department of Anesthesiology The Second Affiliated Hospital of the Chinese People’s Liberation Army Air Force Medical UniversityXi’an710038China

Objective:To assess the analgesic and anti-inflammatory effects of standardized extract of Cotinus coggygria(***)in different animal ***:*** extracts(25,50,and 100 mg/kg)were administered to rats and mice(n=6)during hot plate,tail-flick,acetic acid-induced writhing,and formalin tests to determine its analgesic *** anti-inflammatory activity of *** extracts was evaluated by histamine and carrageenan-induced paw edema,cotton pellet-induced granuloma,and acetic acid-induced peritoneal capillary dye leakage ***:*** extracts(50 and 100 mg/kg)significantly alleviated thermal and chemical-induced pain in rodents(P<0.05).It also demonstrated notable anti-inflammatory properties by mitigating histamine and carrageenan-induced paw edema,granuloma deposits,and vascular permeability(P<0.05).Moreover,*** extracts remarkably reduced TNF-α,IL-1β,IL-6,COX-2,and oxidative stress in rat paws(P<0.05).Carrageenan-induced histological aberrations in hind paw tissues were effectively(P<0.05)mitigated by treatment with *** ***:*** *** show analgesic and anti-inflammatory effects via inhibition of COX-2 and inflammatory and oxidative mediators.

关键词： Antioxidant Carrageenan Cotinus coggygria Scop. Anti-inflammatory Analgesic Pain TNF-α Fustin

Predicting submerged vegetation drag with a machine learning-based method

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Journal of Hydrodynamics 2024年第3期36卷 534-545页

作者： Meng-yang Liu hong-wu Tang Sai-yu yuan Jing yan College of Water Conservancy and Hydropower Engineering Hohai UniversityNanjing210098China Key Laboratory of Hydrologic-Cycle and Hydrodynamic-System of Ministry of Water Resources Hohai UniversityNanjing210098China

Accurate estimation of the drag forces generated by vegetation stems is crucial for the comprehensive assessment of the impact of aquatic vegetation on hydrodynamic processes in aquatic *** coupling relationship between vegetation layer flow velocity and vegetation drag makes precise prediction of submerged vegetation drag forces particularly *** present study utilized published data on submerged vegetation drag force measurements and employed a genetic programming(GP)algorithm,a machine learning technique,to establish the connection between submerged vegetation drag forces and flow and vegetation *** using the bulk velocity,U,as the reference velocity scale to define the drag coefficient,C_(d),and stem Reynolds number,the GP runs revealed that the drag coefficient of submerged vegetation is related to submergence ratio(H^(*)),aspect ratio(d^(*)),blockage ratio(ψ^(*)),and vegetation density(λ).The relation between vegetation stem drag forces and flow velocity is implicitly embedded in the definition of C_(d).Comparisons with experimental drag force measurements indicate that using the bulk velocity as the reference velocity,as opposed to using the vegetation layer average velocity,U_(v),eliminates the need for complex iterative processes to estimate U_(v)and avoids introducing additional errors associated with U_(v)*** approach significantly enhances the model’s predictive capabilities and results in a simpler and more user-friendly formula expression.

关键词： Drag coefficient genetic programming algorithm submerged vegetation flow resistance cylinder array