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

废旧GFRP回收及其增强沥青性能

北京工业大学学报 2024年第4期50卷 443-452页

作者：余森开林娇王大为中铁十六局集团路桥工程有限公司北京101500 哈尔滨工业大学交通科学与工程学院哈尔滨150090

玻璃纤维增强复合材料(glass fiber reinforced polymer,GFRP)因其优异的力学性能和耐腐蚀性而广泛应用于航空、船舶和风力发电等领域。GFRP的广泛使用导致大量废弃物的产生,对环境造成了巨大的危害,因此废旧GFRP的回收处理问题备受关... 详细信息

玻璃纤维增强复合材料(glass fiber reinforced polymer,GFRP)因其优异的力学性能和耐腐蚀性而广泛应用于航空、船舶和风力发电等领域。GFRP的广泛使用导致大量废弃物的产生,对环境造成了巨大的危害,因此废旧GFRP的回收处理问题备受关注。将废旧环氧基GFRP和聚氨酯基GFRP破碎粉末(直径<0.075 mm)作为沥青增强材料,研究了其对沥青基本性能的影响,并对比了硅烷偶联剂对增强作用的影响。结果表明,2种GFRP粉末对沥青的增强作用并不明显,而使用硅烷偶联剂对GFRP粉末进行表面处理后,能够显著改善GFRP粉末与沥青间相互作用,并提高沥青的流变性能和表面自由能,降低玻璃化转变温度,其中硅烷偶联剂对环氧基GFRP的改善效果优于聚氨酯基GFRP。该文为废弃GFRP提供了一种相对有效且环保的物理回收方法,并为纤维增强复合材料(fiber reinforced polymer,FRP)的回收利用提供了新思路。

关键词：玻璃纤维增强复合材料(GFRP) 固体废弃物回收利用沥青增强作用,表面处理

Energy Efficient Transmission in Underlay CR-NOMA Networks Enabled by Reinforcement Learning

在线全文

学校读者我要写书评

暂无评论

China Communications 2020年第12期17卷 66-79页

作者： Wei Liang Soon Xin ng Jia Shi Lixin Li dawei Wang School of Information and Electronic Northwestern Polytechnical UniversityNo.127Youyixi RoadXi’an 710072China School of Electrical and Computer Science University of SouthamptonUK State Key Lab.of Integrated Services Networks Xidian UniversityNo.2Taibainan RoadXi’an 710071China

In order to improve the energy efficiency(EE)in the underlay cognitive radio(CR)networks,a power allocation strategy based on an actor-critic reinforcement learning is proposed,where a cluster of cognitive users(CUs)can simultaneously access to the same primary spectrum band under the interference constraints of the primary user(PU),by employing the non-orthogonal multiple access(NOMA)*** the proposed scheme,the optimization of the power allocation is formulated as a non-convex optimization ***,the power allocation for different CUs is based on the actor-critic reinforcement learning model,in which the weighted data rate is set as the reward function,and the generated action strategy(*** power allocation)is iteratively criticized and *** the CU’s spectral efficiency and the PU’s interference constrains are considered in the training of the actor-critic reinforcement ***,the first order Taylor approximation as well as other manipulations are adopted to solve the power allocation optimization problem for the sake of considering the conventional channel *** to the simulation results,we find that our scheme could achieve a higher spectral efficiency for the CUs compared to a benchmark scheme without learning process as well as the existing Q-learning based method,while the resultant interference affecting the PU transmission can be maintained at a given tolerated limit.

关键词： cognitive radio network non-orthogonal multiple access scheme power allocation reinforcement learning

在线全文

学校读者我要写书评

暂无评论

海水溶解态镍的现场快速检测系统构建及应用

分析科学学报 2024年第4期40卷 461-466页

作者：樊霞潘大为梁艳魏红中国科学院烟台海岸带研究所中国科学院海岸带环境过程与生态修复重点实验室山东烟台264003 山东省海岸带环境过程重点实验室山东烟台264003 中国科学院大学北京100049 山东盐碱地现代农业有限责任公司山东东营257347

镍是海洋生物的必需元素,影响着海洋中甲烷生成、氮吸收等过程。现场快速检测海水中溶解态镍将为海洋环境监测应急预警提供技术支持。为减少储存或运输等条件变化对镍浓度的影响,本研究采用电化学吸附阴极溶出伏安法,结合便携式电化学... 详细信息

镍是海洋生物的必需元素,影响着海洋中甲烷生成、氮吸收等过程。现场快速检测海水中溶解态镍将为海洋环境监测应急预警提供技术支持。为减少储存或运输等条件变化对镍浓度的影响,本研究采用电化学吸附阴极溶出伏安法,结合便携式电化学工作站,构建了海水中溶解态镍的现场快速检测系统。通过性能优化,该检测系统对镍的检出限为30.00 ng/L,线性范围为0.10~100.00μg/L(R^(2)=0.997),单个样品检测时间<10 min。该检测系统成功用于黄海、东海、南海3个典型养殖区的现场快速检测研究。检测结果表明,3个养殖区溶解态镍含量均符合一级海水水质要求(≤5.00μg/L),但黄海、南海养殖区浓度低,东海浓度相对较高。

关键词：海水溶解态镍快速检测系统现场检测

在线全文

学校读者我要写书评

暂无评论

严重烧伤小鼠肠-胰岛轴功能的变化及其作用

中华烧伤与创面修复杂志 2024年第7期40卷 625-633页

作者：刘馨竹李大伟蒋敏李志生冯柏塨申传安解放军总医院第四医学中心烧伤整形医学部北京100048

目的探讨严重烧伤小鼠肠-胰岛轴功能的变化及其作用。方法该研究为实验研究。将90只雄性8~10周龄C57BL/6J小鼠按随机数字表法分为假伤组和烧伤组(每组45只小鼠),于烧伤组小鼠背部制备30%体表总面积Ⅲ度烫伤(以下称烧伤)创面,假伤组小鼠... 详细信息

目的探讨严重烧伤小鼠肠-胰岛轴功能的变化及其作用。方法该研究为实验研究。将90只雄性8~10周龄C57BL/6J小鼠按随机数字表法分为假伤组和烧伤组(每组45只小鼠),于烧伤组小鼠背部制备30%体表总面积Ⅲ度烫伤(以下称烧伤)创面,假伤组小鼠模拟致假伤。伤后24 h,检测空腹血糖(样本数为12)后,行腹腔糖耐量实验和口服糖耐量实验,并绘制血糖浓度-时间变化曲线,计算曲线下面积(样本数为6);分别于腹腔注射或灌胃给予葡萄糖溶液前及腹腔注射或灌胃给予葡萄糖溶液后30、60、120 min从心脏取血,采用酶联免疫吸附测定(ELISA)法检测血浆胰岛素和胰高血糖素样肽1(GLP-1)水平(样本数为3);取每组3只小鼠回肠组织,行免疫荧光染色及原位末端标记染色检测肠道L细胞GLP-1表达及凋亡水平;提取每组6只小鼠胰岛行葡萄糖刺激的胰岛素分泌实验,分别经低糖(2.8 mmol/L葡萄糖)和高糖(16.7 mmol/L葡萄糖)孵育后取上清液,采用ELISA法检测胰岛素水平。取36只雄性8~10周龄C57BL/6J小鼠,按随机数字表法分为假伤组、烧伤组和烧伤+艾塞那肽4(Ex-4)组(每组12只小鼠),对假伤组和烧伤组小鼠行同前对应处理,将烧伤+Ex-4组小鼠同烧伤组小鼠致伤后给予其GLP-1受体激动剂Ex-4。伤后24 h,提取小鼠胰岛,采用蛋白质印迹法检测重链结合蛋白(BIP)、蛋白激酶R样内质网激酶(PERK)、磷酸化PERK(p-PERK)、真核翻译起始因子2α(eIF2α)、磷酸化eIF2α(p-eIF2α)和CCAAT/增强子结合蛋白同源蛋白(CHOP)的蛋白表达并计算p-PERK/PERK、p-eIF2α/eIF2α比值(样本数为3),采用流式细胞术检测胰岛细胞凋亡率(样本数为3),同前行葡萄糖刺激的胰岛素分泌实验以检测上清液中胰岛素水平(样本数为6)。结果伤后24 h,烧伤组小鼠空腹血糖为(7.3±1.0)mmol/L,显著高于假伤组的(5.1±0.6)mmol/L(t=6.36,Png/mg,显著低于假伤组的(15.7±0.3)ng/mg(t=18.68,P<0.05)。伤后24 h,与假伤组相比,烧伤组小鼠胰岛中BIP、p-PERK/PERK、p-eIF2α/eIF2α和CHOP的蛋白表达水平均显著升高(P<0.05);与烧伤组相比,烧伤+Ex-4组小鼠胰岛中BIP、p-PERK/PERK、p-eIF2α/eIF2α和CHOP的蛋白表达水平均显著降低(P<0.05)。伤后24 h,烧伤组小鼠胰岛细胞凋亡率为(32.0±3.0)%,显著高于假伤组的(10.3±2.5)%(P<0.05);烧伤+Ex-4组小鼠胰岛细胞凋亡率为(20.0±3.6)%,显著低于烧伤组(P<0.05)。伤后24 h,烧伤组小鼠经高糖孵育的胰岛上清液中胰岛素水平显著低于假伤组(P<0.05),烧伤+Ex-4组小鼠经高糖孵育的胰岛上清液中胰岛素水平显著高于烧伤组(P<0.05)。结论严重烧伤后小鼠肠-胰岛轴功能障碍,肠道L细胞凋亡增多、GLP-1合成及分泌减少,胰岛细胞发生内质网应激、凋亡增多,葡萄糖刺激的胰岛素分泌减少;GLP-1受体激动剂Ex-4能保护严重烧伤小鼠胰岛细胞功能,可能通过减轻内质网应激降低胰岛细胞凋亡水平,促进胰岛素分泌。

关键词：烧伤胰岛素胰高血糖素样肽1 内质网应激高糖血症肠-胰岛轴

贵州省典型铅锌矿区和贵阳市居民汞暴露以及健康风险评估

在线全文

学校读者我要写书评

暂无评论

生态学杂志 2024年第3期43卷 869-877页

作者：王达卫孔林徐晓航韩佳良刘杰民仇广乐中国科学院地球化学研究所环境地球化学国家重点实验室贵阳550081 中国科学院大学北京100049 贵州医科大学公共卫生学院环境污染与疾病监控教育部重点实验室贵阳550025 贵州省人民医院贵阳550025

选择贵州省赫章县铅锌矿区和贵阳市居民区,采集了居民日用食物(大米、土豆、鸡蛋、蔬菜、鱼肉、猪肉)、饮用水和农作物根际土壤,共计503个,测定了总汞和甲基汞的含量,并结合蒙特卡洛模拟评估了居民无机汞和甲基汞暴露风险。结果如下:(1... 详细信息

选择贵州省赫章县铅锌矿区和贵阳市居民区,采集了居民日用食物(大米、土豆、鸡蛋、蔬菜、鱼肉、猪肉)、饮用水和农作物根际土壤,共计503个,测定了总汞和甲基汞的含量,并结合蒙特卡洛模拟评估了居民无机汞和甲基汞暴露风险。结果如下:(1)铅锌矿区的样品总汞和甲基汞的范围分别为0.11~39和0.028~1.7 ng·g^(-1),城市居民区的样品总汞和甲基汞的范围分别为0.07~18和0.01~7.7 ng·g^(-1),除蔬菜外的样品总汞含量低于我国食品限量标准,蔬菜总汞含量分别有14.7%(铅锌矿区)和17.7%(城市居民区)的样品超过我国《食品安全国家标准》(GB 2672—2017)规定的10 ng·g^(-1)。(2)两个地区无机汞日暴露量无差异(城市居民区:0.031μg·kg^(-1)·d-1,铅锌矿区:0.032μg·kg^(-1)·d-1),但城市居民区的甲基汞日暴露量(0.006μg·kg^(-1)·d-1)高出铅锌矿区(0.0032μg·kg^(-1)·d-1)近1倍。(3)两个地区居民无机汞和甲基汞的平均日暴露量分别低于联合国粮农组织/世界卫生组织食品添加剂联合专家委员会(JECFA)推荐的人体安全无机汞的临时容许每周摄入量(PTWI)4μg·kg^(-1)·week-1和美国环境保护署(USEPA)推荐的甲基汞参考剂量(RfD)0.1μg·kg^(-1)·d-1,暴露风险指数均小于1,表明处于健康安全水平。

关键词：铅锌矿区贵阳市居民区无机汞甲基汞风险评估

Heavy metals in sediments of Yellow Sea and East China Sea: Chemical speciation,distribution,influence factor,and contamination

在线全文

学校读者我要写书评

暂无评论

Journal of Oceanology and Limnology 2021年第4期39卷 1277-1292页

作者： Miao zhAO Shenghui zh.ng Haitao HAN dawei PAN Key Laboratory of Coastal Environmental Processes and Ecological Remediation Yantai Institute of Coastal Zone Research(YIC)Chinese Academy of Sciences(CAS)Coastal Environmental ProcessesResearch Center for Coastal Environment Engineering Technology of Shandong ProvinceYICCASYantai 264003China University of Chinese Academy of Sciences Beijing 100049China

Metal species and the degree of environmental pollution are related to the hydrogen sulfide(H_(2)S),an important product of early diagenesis that can react with metals to form stable *** investigate the eff ects of H_(2)S to metals and evaluate metal environment eff ect in the sediments of the East China Sea(ECS)and Yellow Sea(YS),geochemical characteristic and spatial distribution of nine heavy metals and H_(2)S profile were *** H_(2)S content and lower metal content was observed in the sediments 10 cm in depth in the North Yellow Sea and the west coast of South *** pollution load index(I_(pl))indicates that the southern coast of Shandong Peninsula underwent moderate pollution(I_(pl)=1)of heavy metals and no heavy metal pollution appeared in other areas(I_(pl)ng summer was 21%.In addition,correlation between H_(2)S content and metals in both solid and porewater phases was obvious,corroborating important eff ect of H_(2)S on metal ***,H_(2)S could aff ect the spatial distributions of heavy metals in porewater directly and be indicative of potential biological eff ects of combined toxicant groups in the study region.

关键词： hydrogen sulfide heavy metal East China Sea and Yellow Sea sediment porewater risk assessment

Eco-friendly and Cleaner Process Using Online Microwave-assisted Steam Extraction Coupled with Solid-phase Extraction for Trace Analysis of Sulfonamides in Animal Feed

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2018年第6期34卷 893-898页

作者： LI Guijie LIU Chang WAng dawei DIng Lan College of Food Science Jilin Agricultural University Changchun 130118 P. R. China College of Chemistry Jilin University Changchun 130012 P. R. China Jilin Province Product Quality Supervision and Inspection Institute Changchun 130103 P. R. China

An environmentally friendly method for extracting sulfonamides（SAs） residues from animal feed was described and applied. The method used online microwave-assisted steam extraction coupled with solid phase extraction（MASE-SPE）, which was followed by the analysis using high performance liquid chromatography-mass spectro- metry（HPLC-MS/MS）. The SAs residues were extracted successively with water steam under microwave irradiation, and thus directly introduced into an SPE colunm containing cation-exchange resin. The SAs were then eluted with methanol-ammonia（90：10, volume ratio） from the SPE column and followed by HPLC-MS/IVIS. The limits of detec- tion（LODs） for the analytes ranged from 0.24 ng/g to 0.49 ng/g. The limits of quantification（LOQs） ranged from 0.82 ng/g to 1.63 ng/g. Average recoveries of SAs were 76.3%--92.1%. The developed method was a reliable and envi-ronmentally friendly alternative to previous methods with respect to time, solvent and labor consumption for the analysis of SAs in animal foodstuffs.

关键词： High performance liquid chromatography-mass spectrometry Microwave-assisted steam extraction Solid-phase extraction Sulfonamide Animal feed

Four Coordination Polymers Assembled with a New Biscarboxyl-functionalized Schiff Base Ligand

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

Chemical Research in Chinese Universities 2018年第5期34卷 839-843页

作者： KAng dawei XIE Jingjing LIU Yingying MA Jianfang Key Laboratory of Polyoxometalate Science Department of Chemistry Northeast Normal University Changchun 130024 P. R. China Inner Mongolia Key Lab of Chemistry of Natural Products and Synthesis of Functional Molecules College of Chemistry and Chemical Engineering lnner Mongolia University for the Nationalities Tongliao 028000 P. R. China

Based on a new biscarboxyl-functionalized Schiff base ligand 1,2-cyclohexanediamino-N,N＇-bis[3- methoxyl-5-（p-carboxyl-phenylazo）] salicylidene（H4L）, four polymers, [（CH3）：NH2]2.[Mn3（L）2（H2O）4]·2DMF（CP1）, [Fe2（L）（H2O）（DMF）]（CP2）, [（CH3）2ng2].[Cu（HL）]·H2O（CP3） and [Ni2（L）（teta）]·2DMF·H2O（CP4）, have been synthesized（teta=5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane）. In CPI, both of the internal [N202] pocket and the external carboxylate groups of L＊- anion are ligated by Mn2＋ ions, and the structure displays a layer. In CP2, the Fe^2＋ cations are linked by L4- anions to form a binuclear double chain. CP3 displays a [Cu2（I-IL）2] dimer. In CP4, the Ni^2＋ ions are connected by L4- anions to form a chain. The structures are further linked by hydrogen bonds to form 2D or 3D supramolecular architectures, respectively. CP1 exhibits adsorption ability to three organic dyes.

关键词： Coordination polymer Schiffbase Carboxylic acid Dye adsorption

Novel sulfhydryl functionalized covalent organic frameworks for ultra-trace Hg^(2+) removal from aqueous solution

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 Materials Science & Technology 2021年第34期93卷 89-95页

作者： Fei Pan Chunyi Tong zhaoyang Wang Fenghua Xu Xiaofei Wang Baicheng Weng dawei Pan Rilong zhu College of Chemistry and Chemical Engineering.Advanced Catalytic Engineering Research Center of the Ministry of Education Hunan UniversityChangsha410082.PR China CAS Key Laboratory of Coastal Environmental Processes and Ecological Remediation Shandong Key Laboratory of Coastal Environmental ProcessesResearch Center for Coastal Environment Engineering Technology of Shandong ProvinceYantai Institute of Coastal Zone Research.Chinese Academy of Sciences.Yantai 264003PR China University of Chinese Academy of Sciences Beijing100049PR China College of Chemistry and Chemical Engineering Central South UniversityChangsha410083PR China School of Environmental Science and Engineering Hubei Polytechnic UniversityHuangshi435003PR China

Two kinds of novel sulfhydryl functionalized covalent organic frameworks were fabricated as adsorbents for the removal of ultra-trace concentrations of Hg^(2+)from *** two kinds of sulfhydryl functionalized covalent organic frameworks were obtained via a thiol-ene click reaction between the thiol groups of trithiocyanuric acid(TTC)or bismuththiol(BMT)and vinyl groups on the surface of covalent organic *** material structure was characterized by XRD,SEM,EDS,FT-IR,BET,and TG *** to their rich sulfur content,both adsorbents(COF-SH-1 and COF-SH-2)exhibited a high level of selective Hg^(2+)removal from aqueous solution with maximum adsorption capacities of 763.4 mg g^(-1) and526.3 mg g^(-1),***,in the presence of ultra-low concentrations of Hg^(2+)both materials exhibited excellent performance,achieving rapid Hg^(2+)removal at concentrations from 10μg L^(-1) to less than 0.02 ng L^(-1).Analysis of the adsorption mechanism indicates that the sulfur containing chelating groups exhibit a strong binding capacity for Hg^(2+).Results show that the structure determines the performance,with the amount of adsorption sites being related to the adsorption ***,as sulfhydryl functionalized covalent organic frameworks contain an abundance of adsorption sites,these materials can effectively achieve the removal of ultra-low trace Hg^(2+)concentrations and have promising future application potential for the environmental detection of heavy metals.

关键词： Sulfhydryl-functionalized Covalent organic framework Ultra-trace adsorption Mercury adsorption