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Distribution and Contamination of Arsenic in Fish, Gastropods and Bivalves in the Aby and Tendo Lagoons in East of Ivory Coast
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作者 Kouakou Serge Kouassi Stéphane Jean Claon +3 位作者 Kossonou Roland N’Guettia Séri Kipré Laurent Dakouo Guei Jokebed Djaman Allico Joseph 《Journal of Environmental Protection》 2024年第3期246-264,共19页
Lagoons are ecosystems for biodiversity and the livelihoods of coastal communities. The main objective of the study was to analyze the variability of arsenic concentrations in gastropods and bivalves in the Aby and Te... Lagoons are ecosystems for biodiversity and the livelihoods of coastal communities. The main objective of the study was to analyze the variability of arsenic concentrations in gastropods and bivalves in the Aby and Tendo lagoons, taking into account spatial, seasonal and hydrological variations. The study was carried out in four stages spread over two successive hydroclimatic cycles, including two seasons during the rainy season and two more during the dry season. The samples were taken in two areas of the Aby and Tendo lagoons. Arsenic levels were measured by ICP-MS. The results showed that mean arsenic concentrations in the muscles of organisms in Aby Lagoon ranged from 0.01 to 1.26 μg As/g, with a mean and median of 0.17 and 0.06 μg As/g, respectively. Fish had the highest levels of arsenic, followed by crustaceans, while molluscs and plants had lower and comparable concentrations of As. Arsenic concentrations in tilapia and jawbones varied significantly between sites and seasons, with higher concentrations at Tendo and during the rainy season. Arsenic concentrations in gastropods and bivalves were significantly higher than those of other species, with averages of 0.74 and 1.03 mg As/kg, respectively. 展开更多
关键词 arsenic Pollution FISH GASTROPODS LAGOONS Health Effect
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Roles of Aqueous Extract of Marigold on Arsenic-Induced Oxidative Damage in Pancreatic Islet β-Cells
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作者 Zongqin Mei Jiao Dai +2 位作者 Guofen Liu Zuoshun He Shiyan Gu 《Journal of Biosciences and Medicines》 2024年第5期19-34,共16页
Roles of Marigold extracts (ME) on arsenic trioxide (ATO)-induced oxidative damage to pancreatic β-cells need to be further elucidated. In this study, NIT-1 cells were treated with different concentrations of and/or ... Roles of Marigold extracts (ME) on arsenic trioxide (ATO)-induced oxidative damage to pancreatic β-cells need to be further elucidated. In this study, NIT-1 cells were treated with different concentrations of and/or ATO, following by the cell viability was detected by CCK8 assay. Then, intracellular reactive oxygen species (ROS) levels, lipid peroxide (MDA) contents and superoxide dismutase (SOD) activity were measured with a fluorescence probe method and colorimetric assay, respectively. The apoptosis rate and morphology was detected and observed with hoechst 33,258 staining assay. The mRNA levels and protein expressions of nuclear factor E2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) were measured by real-time fluorescence quantitative polymerase chain reaction and protein immunoblotting assay, respectively. Our results indicated that Co-treatment with ME and ATO exacerbated the cell viability decreasing reduced by ATO, while the addition of ME after ATO treatment effectively promote the recovery of ATO reduced survival rates. The ATO group increased apoptosis (P P β-cells by modulating the activation of the Nrf2 signaling pathway. 展开更多
关键词 arsenic Trioxide Marigold Extracts Nuclear Factor E2-Related Factor 2 Oxidative Damage
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Feasibility Evaluation of Using Biochar-based Permeable Reactive Barrier for the Remediation of Mercury and Arsenic Composite Polluted Water Bodies
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作者 Dilixiati·Abulizi 《Asian Agricultural Research》 2024年第5期15-19,共5页
This study employed a modified biochar material to construct a permeable reactive barrier(PRB)for the treatment of water bodies polluted with mercury and arsenic.The experimental results demonstrated that the addition... This study employed a modified biochar material to construct a permeable reactive barrier(PRB)for the treatment of water bodies polluted with mercury and arsenic.The experimental results demonstrated that the addition of goethite-modified biochar significantly enhanced the remediation efficiency of As(III),achieving a maximum removal rate of 100%.Conversely,pure biochar exhibited high efficiency in the removal of Hg(II),with a maximum removal rate approaching 100%.Furthermore,the pH level of the water significantly influenced the adsorption efficiency of heavy metal ions,with the optimal removal performance observed at a pH of 6.0.The PRB system demonstrated excellent removal rates under low concentrations of heavy metals.However,as the concentration increased,the remediation efficiency exhibited a slight decrease.In summary,the findings of this study provide compelling evidence for the use of modified biochar in the construction of PRBs for the remediation of mercury and arsenic-polluted water bodies.Furthermore,the study reveals the mechanism by which pH and heavy metal concentration influence remediation efficiency. 展开更多
关键词 BIOCHAR Goethite-modified biochar Permeable reactive barrier(PRB) Mercury and arsenic pollution Remediation efficiency
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Plant-derived natural compounds in the treatment of arsenic-induced toxicity
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作者 Sanjib Bhattacharya 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2023年第9期369-377,共9页
Arsenic toxicity,imposed mainly by arsenic-contaminated groundwater,is considered a critical threat to global communal health,as there is no specific and proven conventional therapy for chronic arsenic toxicity,i.e.,a... Arsenic toxicity,imposed mainly by arsenic-contaminated groundwater,is considered a critical threat to global communal health,as there is no specific and proven conventional therapy for chronic arsenic toxicity,i.e.,arsenicosis,which is an insidious global public health menace affecting 50 countries.Alternative options should,therefore,be explored for the mitigation of arsenicosis.Literature survey reveals several natural compounds from plants possess significant protective efficacy against arsenic toxicity in chiefly preclinical and few clinical investigations.The studies on the ameliorative effects of plant-derived natural compounds against arsenic toxicity published in the last 25 years are collated.Forty-eight plant-based natural compounds possess alleviative effects on experimental arsenic-induced toxicity in animals,six of which have been reported to be clinically effective in humans.A potential nutraceutical or therapeutic candidate against arsenicosis for humans may thus be developed with the help of recent advancements in research in this area,along with the currently available treatments. 展开更多
关键词 arsenic toxicity arsenicOSIS Natural compounds vITAMINS
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Arsenic removal from acidic industrial wastewater by ultrasonic activated phosphorus pentasulfide
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作者 Bo Yu Guang Fu +6 位作者 Xinpei Li Libo Zhang Jing Li Hongtao Qu Dongbin Wang Qingfeng Dong Mengmeng Zhang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第8期46-52,共7页
Arsenic is one of the main harmful elements in industrial wastewater.How to remove arsenic has always been one of the research hotspots in academic circles.In the process of arsenic removal by traditional sulfuration,... Arsenic is one of the main harmful elements in industrial wastewater.How to remove arsenic has always been one of the research hotspots in academic circles.In the process of arsenic removal by traditional sulfuration,the use of traditional sulfurizing agent will introduce new metal cations,which will affect the recycling of acid.In this study,phosphorus pentasulfide (P_(2)S_(5)) was used as sulfurizing agent,which hydrolyzed to produce H_(3)PO_(4) and H_(2)S without introducing new metal cations.The effect of ultrasound on arsenic removal by P_(2)S_(5) was studied.Under the action of ultrasound,the utilization of P_(2)S_(5) was improved and the reaction time was shortened.The effects of S/As molar ratio and reaction time on arsenic removal rate were investigated under ultrasonic conditions.Ultrasonic enhanced heat and mass transfer so that the arsenic removal rate of 94.5%could be achieved under the conditions of S/As molar ratio of 2.1:1 and reaction time of 20 min.In the first 60 min,under the same S/As molar ratio and reaction time,the ultrasonic hydrolysis efficiency of P_(2)S_(5) was higher.This is because P_(2)S_(5) forms ([(P_(2)S_(4))])^(2+)under the ultrasonic action,and the structure is damaged,which is easier to be hydrolyzed.In addition,the precipitation after arsenic removal was characterized and analyzed by X-ray diffraction,scanning electron microscope-energy dispersive spectrometer,X-ray fluorescence spectrometer and X-ray photoelectron spectroscopy.Our research avoids the introduction of metal cations in the arsenic removal process,and shortens the reaction time. 展开更多
关键词 arsenic removal Mass transfer Precipitation Waste water Ultrasound
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Assessment of Soil Contamination and Human Health Risk around an Industrial Gold Mine in Côte d’Ivoire: The Case of Arsenic
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作者 Kagbagnan Kone Adjoumani Rodrigue Kouakou 《Open Journal of Soil Science》 2023年第7期329-339,共11页
The Tongon mine generates millions of tons of waste rock and tailings, which are stored in landfills in the vicinity of the mine. These tailings contain arsenic. The risk of soil contamination in this area is evident.... The Tongon mine generates millions of tons of waste rock and tailings, which are stored in landfills in the vicinity of the mine. These tailings contain arsenic. The risk of soil contamination in this area is evident. This study assesses the arsenic contamination of soils around the mine and the health risks to the local population. Soil samples were taken from plastic bags and other materials used as working tools. Arsenic concentrations were determined by inductively coupled plasma mass spectroscopy, after the soil samples had been concentrated and digested. Metal contamination indices were used to assess the degree of soil contamination. The results obtained indicate that soils in the industrial zone of the Tongon gold mine have very high average concentrations, well above the world average for uncontaminated soils of 6 mg/kg arsenic. Geoaccumulation index values range from 1.28 to 3.40. These values highlight severe arsenic soil contamination. The human health risk assessment revealed that exposure risks are well above the critical limit of 1 and are, in descending order, children > adult women > adult men. These results indicate an ecological risk, requiring environmental monitoring, underpinned by the development of an effective remediation strategy to reduce local pollution and contamination. 展开更多
关键词 Industrial Mine Tongon POLLUTION arsenic Soil
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Review and Analysis: Fate of Arsenic Applied to Canal Shipping Lane Vegetation and United States Military Base Grounds in the Panama Canal Zone
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作者 Kenneth R. Olson 《Open Journal of Soil Science》 2023年第10期391-413,共23页
The opening of the Panama Canal in 1913 increased the availability of internationally traded goods and transformed ocean-shipping by shortening travel time between the Atlantic Ocean and Pacific Ocean. The canal spark... The opening of the Panama Canal in 1913 increased the availability of internationally traded goods and transformed ocean-shipping by shortening travel time between the Atlantic Ocean and Pacific Ocean. The canal sparked the growth of port authorities and increased ship tonnage on both coasts of Panama. Since the construction of the Panama Canal, in the 1910s, pesticides, herbicides and chemicals, including arsenic, have been essential for controlling wetland vegetation, including hyacinth, which blocked rivers, lakes, and the canal as well as managing mosquitoes. Pesticides and chemicals flowed into Lake Gatun (reservoir) either attached to sediment or in solution during the monsoon season. Lake Gatun was the drinking water source for most of the people living in the Panama Canal Zone. The United States military base commanders had the ability to order and use cacodylic acid (arsenic based) from the Naval Depot Supply Federal and Stock Catalog and the later Federal Supply Catalog on the military base grounds in the Panama Canal Zone. Cacodylic acid was shipped to Panama Canal Zone ports, including Balboa and Cristobal, and distributed to the military bases by rail or truck. The objective of this study is to determine the fate of arsenic: 1) applied between 1914 and 1935 to Panama Canal shipping lane hyacinth and other wetland vegetation and 2) cacodylic acid (arsenic) sprayed from 1948 to 1999 on the US military base grounds in the Panama Canal Zone. 展开更多
关键词 Panama Canal arsenic Hyacinth Lake Gatun Shipping Lanes Cacodylic Acid
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Mechanism, behaviour and application of iron nitrate modified carbon nanotube composites for the adsorption of arsenic in aqueous solutions
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作者 Yingli Li Zhishuncheng Li +5 位作者 Guangfei Qu Rui Li Shuaiyu Liang Junhong Zhou Wei Ji Huiming Tang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第8期26-36,共11页
In this study,ferric nitrate modified carbon nanotube composites (FCNT) were prepared by isovolumetric impregnation using carbon nanotubes (CNTs) as the carrier and ferric nitrates the active agent.The batch experimen... In this study,ferric nitrate modified carbon nanotube composites (FCNT) were prepared by isovolumetric impregnation using carbon nanotubes (CNTs) as the carrier and ferric nitrates the active agent.The batch experiments showed that FCNT could effectively oxidize As(III) to As(V) and react with it to form stable iron arsenate precipitates.When the dosage of FCNT was 0.1 g·L^(–1),pH value was 5–6,reaction temperature was 35℃ and reaction time was 2 h,the best arsenic removal effect could be achieved,and the removal rate of As(V) could reach 99.1%,which was always higher than 90%under acidic conditions.The adsorption results of FCNT were found to be consistent with Langmuir adsorption by static adsorption isotherm fitting,and the maximum adsorption capacity reached 118.3 mg·g^(-1).The material phase and property analysis by scanning electron microscopy,Brunauer–Emmett–Teller,Fourier transform infrared spectoscopy,X-ray photoelectron spectroscopy and other characterization methods,as well as adsorption isotherm modeling,were used to explore the adsorption mechanism of FCNT on arsenic.It was found that FCNT has microporous structure and nanostructure,and iron nanoparticles are loosely distributed on CNTs,which makes the material have good oxidation,adsorption and magnetic separation properties.Arsenic migrates on the surface of FCNT composites is mainly removed by forming insoluble compounds and co-precipitation.All the results show that FCNT treats arsenic at low cost with high adsorption efficiency,and the results also provide the experimental data basis and theoretical basis for arsenic contamination in groundwater. 展开更多
关键词 Carbon nanotubes AS(v) ADSORPTION Nanocomposites Impregnation method
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V型折叠颏下皮瓣修复口腔缺损的临床应用
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作者 卢若煌 邓浩斌 +2 位作者 郭新程 戴捷 甘平平 《中南大学学报(医学版)》 CAS CSCD 北大核心 2024年第2期273-278,共6页
目的:口腔中小型缺损修复一直是一个难题,游离皮瓣和远位带蒂组织瓣难以满足临床需求,传统颏下皮瓣存在供区损伤风险。本研究旨在探讨V型折叠颏下皮瓣修复口腔中小型缺损的疗效。方法:回顾性分析2019年3月至2022年12月中南大学湘雅三医... 目的:口腔中小型缺损修复一直是一个难题,游离皮瓣和远位带蒂组织瓣难以满足临床需求,传统颏下皮瓣存在供区损伤风险。本研究旨在探讨V型折叠颏下皮瓣修复口腔中小型缺损的疗效。方法:回顾性分析2019年3月至2022年12月中南大学湘雅三医院口腔科收治的28例口腔黏膜病变患者的临床资料。根据颏下皮瓣手术方式的不同将患者分为V型折叠组(17例)和传统组(11例),V型折叠组采用V型折叠颏下皮瓣进行术后软组织修复,传统组采用传统颏下皮瓣进行修复,患者术后随访6~48个月。比较2组皮瓣存活情况、皮瓣修复时间以及皮瓣修复效果。结果:2组皮瓣存活率、皮瓣大小、制瓣时间、修复手术时间和术后住院时间差异均无统计学意义(均P>0.05)。术后6个月,V型折叠组无抬头困难和下唇外翻,无皮肤“猫耳”畸形,疤痕隐藏于下颌骨下缘处,创面美观度、功能评分均明显高于传统组(均P<0.05)。结论:V型折叠颏下皮瓣具有设计灵活、制备简单、血供可靠、保护供区等优点,可以有效维持颏部美观和避免功能障碍。 展开更多
关键词 v型折叠颏下皮瓣 黏膜缺损 创面修复
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鼠疫耶尔森菌低钙应答V抗原人源单克隆抗体筛选与鉴定
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作者 张黎 郑滨洋 +5 位作者 张琪 吴海莲 潘红星 朱凤才 吴海生 周剑芳 《中国人兽共患病学报》 CAS CSCD 北大核心 2024年第1期15-20,共6页
目的筛选抗低钙应答V抗原(LcrV)的人源单克隆抗体,分析抗体基因特点,检测抗体与抗原结合的特异性、亲和力及功能。方法使用PCR方法从鼠疫疫苗临床试验志愿者外周血细胞cDNA扩增抗体轻、重链可变区基因片段,构建ScFv噬菌体抗体文库。用L... 目的筛选抗低钙应答V抗原(LcrV)的人源单克隆抗体,分析抗体基因特点,检测抗体与抗原结合的特异性、亲和力及功能。方法使用PCR方法从鼠疫疫苗临床试验志愿者外周血细胞cDNA扩增抗体轻、重链可变区基因片段,构建ScFv噬菌体抗体文库。用LcrV对文库进行富集筛选,将获得的抗体基因表达成人IgG1后,测定抗体与LcrV抗原结合的特异性、亲和力、免疫调节功能以及保护能力。结果成功构建了鼠疫耶尔森菌人源ScFv抗体文库,库容量为7.54×10^(8)。抗体文库经LcrV筛选后获得了3株抗LcrV抗体,命名为RV-B4、RV-D1和RV-E8。3株抗体重链为VH1-46和VH3-30,轻链分别为VL1-51、VK3-20和VK1-39。3株抗体经ELISA及Western blot验证均与LcrV特异性结合,其与V抗原结合的解离常数(KD)分别为2.1 nmol/L、1.24 nmol/L和42 nmol/L。RV-D1体外降低人THP-1分泌TNF-α,动物攻毒试验中未发现抗LcrV抗体的保护效果。结论从鼠疫疫苗免疫人群获得了靶向低钙应答V抗原的人源抗体,以结合抗体为主,不能有效阻断病菌感染。所获得的单抗为鼠疫免疫基础研究、鼠疫诊断应用提供了候选材料。 展开更多
关键词 鼠疫耶尔森菌 低钙应答v抗原 噬菌体展示 重组抗体 保护效果
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V区温度及螺杆转速对挤压膨化牛肉制品理化性质的影响
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作者 张根生 田阳 +2 位作者 李思锦 韩冰 费英敏 《中国调味品》 CAS 北大核心 2024年第3期68-73,91,共7页
利用挤压膨化技术加工高粱-山药-牛肉混合物料,以水溶性、吸水性、色差值、粒度、质构、膨化度、糊化度及红外光谱各基团峰值为指标,分析V区温度和螺杆转速对挤压膨化产品理化性质的影响。结果表明,提高V区温度能够提高产品的红度值、... 利用挤压膨化技术加工高粱-山药-牛肉混合物料,以水溶性、吸水性、色差值、粒度、质构、膨化度、糊化度及红外光谱各基团峰值为指标,分析V区温度和螺杆转速对挤压膨化产品理化性质的影响。结果表明,提高V区温度能够提高产品的红度值、黄度值、硬度、脆度和咀嚼度,吸水性、水溶性、粒度、膨化度、糊化度及红外光谱各基团峰值呈先上升后下降的趋势,亮度值显著下降(P<0.05);同时,随着螺杆转速的提升,产品的红度值、黄度值和糊化度显著下降(P<0.05),吸水性、水溶性、粒度和膨化度呈先上升后下降的趋势,硬度、脆度、咀嚼度及红外光谱各基团峰值先下降后上升,亮度值显著下降(P<0.05)。综合理化指标确定V区温度最佳值为150℃,螺杆转速最佳值为160 r/min。 展开更多
关键词 挤压膨化 理化性质 v区温度 螺杆转速
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基于ⅢF A/V规范和Avalon系统的大学图书馆视听数据库建设研究
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作者 张毅 熊泽泉 +1 位作者 胡晓明 陈丹 《图书馆杂志》 北大核心 2024年第1期50-58,49,共10页
随着中国网络基础设施的不断改善,视听媒体在年轻一代中非常流行,给以文本资源为主的图书馆带来了挑战。本研究旨在探究国内外大学图书馆视听资源数据库建设的现状,借鉴ⅢF规范在图像资源管理方面的成功经验和各种视听保存社区的实践,... 随着中国网络基础设施的不断改善,视听媒体在年轻一代中非常流行,给以文本资源为主的图书馆带来了挑战。本研究旨在探究国内外大学图书馆视听资源数据库建设的现状,借鉴ⅢF规范在图像资源管理方面的成功经验和各种视听保存社区的实践,提出基于ⅢF A/V规范与开源软件的中国大学图书馆视听资源管理方法。通过分析华东师范大学图书馆在视听资源保存、流媒体发布、时间轴气泡注释、转录、视听结构化和开放共享方面的实践,进行实证研究。 展开更多
关键词 视听数据库 ⅢF A/v Avalon媒体系统 视听可视化
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罗汉果皂苷V对RSL3诱导的SH-SY5Y细胞铁死亡的抑制作用及其机制
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作者 刘艳 夏荣松 +2 位作者 冉冬芝 彭哲 王红 《中国病理生理杂志》 CAS CSCD 北大核心 2024年第6期1033-1042,共10页
目的:探讨罗汉果皂苷V(MV)对铁死亡诱导剂RAS选择性致死分子3(RSL3)诱导的人神经母细胞瘤SH-SY5Y细胞铁死亡的抑制作用及可能机制。方法:用RSL3诱导SH-SY5Y细胞建立铁死亡模型。MTT法检测细胞活力;倒置显微镜观察细胞形态;亚铁离子荧光... 目的:探讨罗汉果皂苷V(MV)对铁死亡诱导剂RAS选择性致死分子3(RSL3)诱导的人神经母细胞瘤SH-SY5Y细胞铁死亡的抑制作用及可能机制。方法:用RSL3诱导SH-SY5Y细胞建立铁死亡模型。MTT法检测细胞活力;倒置显微镜观察细胞形态;亚铁离子荧光探针FerroFarRed检测细胞内亚铁离子含量;线粒体红色荧光探针MitoTracker Red CMXRos检测线粒体膜电位(MMP);超氧化物阴离子荧光探针二氢乙啶和线粒体超氧化物红色荧光探针MitoSoX Red分别检测细胞内和线粒体内活性氧(ROS)。微板法检测细胞谷胱甘肽(GSH)和丙二醛(MDA)水平。Western blot检测脂酰辅酶A合成酶长链家族成员4(ACSL4)、环加氧酶2(COX-2、)谷胱甘肽过氧化物酶4(GPX4)和溶质载体家族7成员11(SLC7A11)蛋白表达水平。分子对接技术预测MV与ACSL4、COX-2、GPX4和SLC7A11的靶向关系。结果:与control组相比,RSL3组SH-SY5Y细胞活力显著降低(P<0.01),细胞内亚铁离子含量、细胞内和线粒体内ROS水平及MDA水平显著升高(P<0.05或P<0.01),MMP和GSH水平显著降低(P<0.01),ACSL4和COX-2蛋白表达水平显著升高,而GPX4和SLC7A11蛋白表达水平显著降低(P<0.01),提示成功建立了细胞铁死亡模型。MV处理使细胞活力显著升高(P<0.05),细胞内亚铁离子含量、细胞内和线粒体内ROS水平及MDA水平显著降低(P<0.01),MMP和GSH水平显著升高(P<0.05或P<0.01);ACSL4和COX-2蛋白水平显著降低,而GPX4和SLC7A11蛋白水平显著升高(P<0.05或P<0.01)。分子对接结果显示,MV与铁死亡核心蛋白ACSL4、COX-2、GPX4和SLC7A11存在结合位点。结论:MV可抑制RSL3诱导的SH-SY5Y细胞铁死亡的发生,其机制可能与激活SLC7A11/GPX4和抑制ACSL4/COX-2有关。 展开更多
关键词 罗汉果皂苷v 神经母细胞瘤 RSL3化合物 铁死亡 SLC7A11/GPX4信号通路
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不同V型辅助配体构筑的两个镉配位聚合物的合成、结构和荧光性质
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作者 孙述文 王高峰 《无机化学学报》 SCIE CAS CSCD 北大核心 2024年第3期613-620,共8页
在溶剂热条件下,合成了2个基于V型辅助配体(bipmo、bppmo)的镉配位聚合物{[Cd(bipmo)(NDC)]·1.75H_(2)O}_n (1)和{[Cd(bppmo)(NDC)(H_(2)O)]·H_(2)O}_(n) (2),其中H_(2)NDC=2,6-萘二羧酸,bipmo=双(4-(1H-咪唑-1-基)苯基)甲酮,... 在溶剂热条件下,合成了2个基于V型辅助配体(bipmo、bppmo)的镉配位聚合物{[Cd(bipmo)(NDC)]·1.75H_(2)O}_n (1)和{[Cd(bppmo)(NDC)(H_(2)O)]·H_(2)O}_(n) (2),其中H_(2)NDC=2,6-萘二羧酸,bipmo=双(4-(1H-咪唑-1-基)苯基)甲酮,bppmo=双(4-(吡啶-4-基)苯基)甲酮。利用单晶X射线衍射、键价和分析、红外光谱和元素分析对其结构进行了表征。研究发现,配合物1具有二重互穿的{6~3}拓扑结构。配合物2同样是3-连接的{6~3}拓扑,却存在三重穿插结构。分析表明,V型配体对最终结构的形成有很大影响。此外,对配合物1和2的发光性质也进行了详细研究。 展开更多
关键词 键价和 配位聚合物 v型配体 拓扑结构 荧光
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基于V形记忆曲线的汽车轮毂造型衍生设计方法
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作者 孙利 陈永亮 +3 位作者 艾雯 孙倩哲 于鸿飞 吴俭涛 《机械设计》 CSCD 北大核心 2024年第3期163-169,共7页
为提高汽车轮毂造型设计的效率,增强品牌造型识别度,提出一种高效的轮毂造型衍生创新设计方法。通过分析轮毂V形记忆曲线的变化规律和特点,总结出两类V形记忆曲线,并根据控制点数量分别进行了定量化表达;以轮毂造型的5个设计要素为基础... 为提高汽车轮毂造型设计的效率,增强品牌造型识别度,提出一种高效的轮毂造型衍生创新设计方法。通过分析轮毂V形记忆曲线的变化规律和特点,总结出两类V形记忆曲线,并根据控制点数量分别进行了定量化表达;以轮毂造型的5个设计要素为基础,提取轮毂骨骼的特征并建立运算法则,构建基于V形记忆曲线的轮毂造型衍生设计方法;通过参数化实现造型构建方案衍生,验证了该方法的可行性。研究结果表明:基于V形记忆曲线的轮毂造型衍生设计方法提高了轮毂设计效率,实现了轮毂造型创新及提升品牌特征延续的设计目标,为同类型产品的创新设计提供参考。 展开更多
关键词 汽车轮毂造型 造型衍生设计 v形记忆曲线 轮毂骨骼 参数化构建
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切向车铣18CrNiMo7-6钢V形缺口表面三维形貌研究
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作者 王栋 张君宇 +3 位作者 乔瑞勇 赵睿 张志鹏 孙少铮 《机床与液压》 北大核心 2024年第10期8-13,共6页
疲劳试样的缺口加工一直是一个亟需解决的难题。提出一种全新的切向车铣加工缺口工艺,通过理论与试验结合的方法探究了切向车铣对V形缺口表面形貌的影响规律。结果表明:在不同的工艺参数下,切向车铣V形缺口底部会呈现出不同的加工纹理方... 疲劳试样的缺口加工一直是一个亟需解决的难题。提出一种全新的切向车铣加工缺口工艺,通过理论与试验结合的方法探究了切向车铣对V形缺口表面形貌的影响规律。结果表明:在不同的工艺参数下,切向车铣V形缺口底部会呈现出不同的加工纹理方向,提出的理论公式计算出的纹理方向与工件轴线的夹角与实际结果误差很小;缺口底部三维表面粗糙度R_(a)随着铣刀转速n_(c)的升高而减小,随着工件转速n_(w)的升高而变大,随着每齿进给量f_(z)的增加先减小后增大;得到表面粗糙度最优参数组合为n_(c)=6000 r/min,n_(w)=100 r/min,f_(z)=0.0375μm,在此切削参数组合下得到的V形缺口表面粗糙度R_(a)可达到0.075μm。 展开更多
关键词 切向车铣 v形缺口 三维表面粗糙度 纹理方向
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V槽的偏斜度及其分布对微通道流动沸腾特性的影响
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作者 王迎慧 张兴 +1 位作者 龚莹 王耀 《江苏大学学报(自然科学版)》 CAS 北大核心 2024年第4期464-469,共6页
运用VOF模型与用户自定义函数,数值模拟水在V槽微通道内的流动沸腾过程,分析V槽的偏斜度及其分布对通道内气泡的生长、脱离及气液两相流流型变化的影响.研究结果表明:V槽偏斜度会影响微气泡的脱离直径和脱离时间;偏斜度为1.0的V槽对应... 运用VOF模型与用户自定义函数,数值模拟水在V槽微通道内的流动沸腾过程,分析V槽的偏斜度及其分布对通道内气泡的生长、脱离及气液两相流流型变化的影响.研究结果表明:V槽偏斜度会影响微气泡的脱离直径和脱离时间;偏斜度为1.0的V槽对应的气泡脱离直径较偏斜度为0和0.5的V槽分别减小0.063、0.025 mm,脱离时间分别缩短5.20、2.40 ms,气液两相流由泡状流向受限气泡流的转变沿流动方向往后推移2.7 mm,且片段环状流占据区间有所减小;对于偏斜度为1.0的V槽,当其沿流动方向的分布不同时,微通道内气液两相流动呈现不同特征,前疏后密的V槽分布能更好地抑制通道内气泡聚并,通道全程未见片段环状流发生,近壁区液膜可以避免受热面局部干涸,提升微通道流动沸腾换热的稳定性和可靠性. 展开更多
关键词 微通道 气液两相流 v 偏斜度 流动沸腾 气泡
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融合Inception V1-CBAM-CNN的轴承剩余寿命预测模型 被引量:2
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作者 余江鸿 彭雄露 +2 位作者 刘涛 杨文 叶帅 《机电工程》 北大核心 2024年第1期107-114,共8页
针对现有的滚动轴承剩余寿命(RUL)预测方法精度低、轴承健康指标(HI)构建困难等问题,提出了一种基于卷积神经网络(CNN)并融合Inception V1模块和卷积注意力机制模块(CBAM)的滚动轴承RUL预测模型。首先,在CNN中添加了CBAM机制,并进行了... 针对现有的滚动轴承剩余寿命(RUL)预测方法精度低、轴承健康指标(HI)构建困难等问题,提出了一种基于卷积神经网络(CNN)并融合Inception V1模块和卷积注意力机制模块(CBAM)的滚动轴承RUL预测模型。首先,在CNN中添加了CBAM机制,并进行了加权处理,在通道和空间维度对重要特征进行了强化,对次要特征进行了抑制,通过添加改进的InceptionV1模块,提高了CNN通道间信息交互水平,全面提取了退化特征;然后,进行了网络优化,采用全局最大池化(GMP)方法对模型进行了简化,采用Dropout和批量归一化(BN)方法,避免了过拟合,提高了精度,且克服了训练时出现的梯度消失问题;最后,对数据进行了处理,将降噪后的信号重组为三维张量,将其作为HI,构建了退化标签,引入了评价指标,采用PHM2012轴承数据集进行了实验验证,在3种工况下将其与深度神经网络(DNN)、CNN方法、结合注意力机制的残差网络方法(ResNet)进行了对比。研究结果表明:该方法在变负载条件下的平均RMSE为0.033,较其他方法的RMSE值分别降低了86%、78%和69%,在预测精度和泛化能力方面具有明显优势。 展开更多
关键词 滚动轴承 剩余使用寿命 Inception v1模块 卷积注意力机制模块 卷积神经网络 全局最大池化 批量归一化
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基于改进YOLO v5的复杂环境下桑树枝干识别定位方法
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作者 李丽 卢世博 +2 位作者 任浩 徐刚 周永忠 《农业机械学报》 EI CAS CSCD 北大核心 2024年第2期249-257,共9页
为实现复杂自然环境下对桑树嫩叶处枝干的识别检测,改变当前桑叶采摘设备作业过程中依赖人工辅助定位的现状,解决识别目标姿态多样和环境复杂导致的低识别率问题,提出一种基于改进YOLO v5模型的桑树枝干识别模型(YOLO v5-mulberry),并... 为实现复杂自然环境下对桑树嫩叶处枝干的识别检测,改变当前桑叶采摘设备作业过程中依赖人工辅助定位的现状,解决识别目标姿态多样和环境复杂导致的低识别率问题,提出一种基于改进YOLO v5模型的桑树枝干识别模型(YOLO v5-mulberry),并结合深度相机构建定位系统。首先,在YOLO v5的骨干网络中加入CBAM(Convolutional block attention module)注意力机制,提高神经网络对桑树枝干的关注度;并增加小目标层使模型可检测4像素×4像素的目标,提高了模型检测小目标的性能;同时使用GIoU损失函数替换原始网络中的IoU损失函数,有效防止了预测框和真实框尺寸较小时无法正确反映预测框及真实框之间位置关系的情况;随后,完成深度图和彩色图的像素对齐,通过坐标系转换获取桑树枝干三维坐标。试验结果表明:YOLO v5-mulberry检测模型的平均精度均值为94.2%,较原模型提高16.9个百分点,置信度也提高12.1%;模型室外检测时应检测目标数53,实际检测目标数为48,检测率为90.57%;桑树嫩叶处枝干三维坐标识别定位系统的定位误差为(9.4985 mm,11.285 mm,19.11 mm),满足使用要求。该研究可实现桑树嫩叶处枝干的识别与定位,有助于推动桑叶智能化采摘机器人研究。 展开更多
关键词 桑叶采摘 枝干识别定位 YOLO v5 目标检测 注意力机制 坐标转换
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基于YOLO v8n-seg和改进Strongsort的多目标小鼠跟踪方法
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作者 梁秀英 贾学镇 +3 位作者 何磊 王翔宇 刘岩 杨万能 《农业机械学报》 EI CAS CSCD 北大核心 2024年第2期295-305,345,共12页
多目标小鼠跟踪是小鼠行为分析的基本任务,是研究社交行为的重要方法。针对传统小鼠跟踪方法存在只能跟踪单只小鼠以及对多目标小鼠跟踪需要对小鼠进行标记从而影响小鼠行为等问题,提出了一种基于实例分割网络YOLO v8n-seg和改进Strongs... 多目标小鼠跟踪是小鼠行为分析的基本任务,是研究社交行为的重要方法。针对传统小鼠跟踪方法存在只能跟踪单只小鼠以及对多目标小鼠跟踪需要对小鼠进行标记从而影响小鼠行为等问题,提出了一种基于实例分割网络YOLO v8n-seg和改进Strongsort相结合的多目标小鼠无标记跟踪方法。使用RGB摄像头采集多目标小鼠的日常行为视频,标注小鼠身体部位分割数据集,对数据集进行增强后训练YOLO v8n-seg实例分割网络,经过测试,模型精确率为97.7%,召回率为98.2%,mAP50为99.2%,单幅图像检测时间为3.5 ms,实现了对小鼠身体部位准确且快速地分割,可以满足Strongsort多目标跟踪算法的检测要求。针对Strongsort算法在多目标小鼠跟踪中存在的跟踪错误问题,对Strongsort做了两点改进:对匹配流程进行改进,将未匹配上目标的轨迹和未匹配上轨迹的目标按欧氏距离进行再次匹配;对卡尔曼滤波进行改进,将卡尔曼滤波中表示小鼠位置和运动状态的小鼠身体轮廓外接矩形框替换为以小鼠身体轮廓质心为中心、对角线为小鼠体宽的正方形框。经测试,改进后Strongsort算法的ID跳变数为14,MOTA为97.698%,IDF1为85.435%,MOTP为75.858%,与原Strongsort相比,ID跳变数减少88%,MOTA提升3.266个百分点,IDF1提升27.778个百分点,与Deepsort、ByteTrack和Ocsort相比,在MOTA和IDF1上均有显著提升,且ID跳变数大幅降低,结果表明改进Strongsort算法可以提高多目标无标记小鼠跟踪的稳定性和准确性,为小鼠社交行为分析提供了一种新的技术途径。 展开更多
关键词 小鼠行为 多目标跟踪 YOLO v8n-seg Strongsort
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