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基于夹层多模光纤干涉计的可穿戴呼吸传感器 被引量:3
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作者 杨翔文 罗彬彬 +6 位作者 吴德操 邹雪 石胜辉 范俊豪 郭一霖 范成磊 赵明富 《光学学报》 EI CAS CSCD 北大核心 2023年第3期21-30,共10页
提出了一种基于夹层多模光纤干涉计的可穿戴式呼吸传感器。该传感单元是将一段长度为1~3 mm的渐变型多模光纤(GIMMF)夹在两段长度为1 mm的阶跃型多模光纤(SIMMF)之间制作而成的,由于二者芯径不匹配,故会构成光纤马赫-曾德尔干涉光路,其... 提出了一种基于夹层多模光纤干涉计的可穿戴式呼吸传感器。该传感单元是将一段长度为1~3 mm的渐变型多模光纤(GIMMF)夹在两段长度为1 mm的阶跃型多模光纤(SIMMF)之间制作而成的,由于二者芯径不匹配,故会构成光纤马赫-曾德尔干涉光路,其干涉峰的强度对微弯曲非常敏感,在0~2.36 m^(-1)曲率范围内最大灵敏度可达-74.03 dB/m^(-1)。基于此,将该夹层多模光纤干涉计集成到弹性腰带上并固定在人的腹部,通过监测该传感器透射谱中特征峰的强度变化可实时准确地获取呼吸信号。实验结果表明,该传感器可以区分不同类型的呼吸状况,且具有普遍适用性。 展开更多
关键词 光纤光学 夹层多模光纤干涉计 呼吸传感 曲率 弹性腰带
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Toward to agricultural green development by multi-objective zoning and nitrogen nutrient management:a case study in the Baiyangdian Basin,China 被引量:1
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作者 Xiaomeng ZHANG xiangwen fan +6 位作者 Wenqi MA Zhaohai BAI Jiafa LUO Jing YANG Ling LIU Jianjie ZHANG Lin MA 《Frontiers of Agricultural Science and Engineering》 CSCD 2024年第1期140-154,共15页
Although China has achieved great advancements toward national food security,the country is still confronted with a range of challenges,including natural resource stress,imbalanced diets and environmental pollution.Op... Although China has achieved great advancements toward national food security,the country is still confronted with a range of challenges,including natural resource stress,imbalanced diets and environmental pollution.Optimized management of crop–livestock systems is the key measure to realize agricultural green transformation.However,optimized management of crop–livestock systems that use multi-objective zoning is lacking.This study employed a multi-objective zoning management approach to comprehensively analyze four indicators:ammonia volatilization,nitrogen surplus,soil carrying capacity and ecological red line area.With its significant ecological integrity and a strong emphasis on sustainability,the Baiyangdian Basin serves as a unique and suitable test case for conducting analyses on multi-objective nutrient optimization management,with the aim to facilitate the agricultural green transformation.This study finds that less than 8%of the area in the Baiyangdian Basin meet the acceptable environmental indicator standard,whereas around 50%of the area that had both nitrogen surplus and ammonia volatilization exceeded the threshold.Implementation of unified management,that is,the same management technique across the study areas,could result in an increase of areas meeting environmental indicator thresholds to 21.1%.This project developed a novel multi-indicator partition optimization method,in which distinct measures are tailored for different areas to satisfy multiple environmental indicators.Implementation of this method,could potentially bring more than 50%area below the threshold,and areas with ammonia emissions and nitrogen surplus could be reduced to 15.8%.The multi-indicators partition optimization method represents a more advanced and efficiency-oriented management approach when compared to unified management.This approach could be regarded as the best available option to help China achieve agricultural transformation to improve efficient production and reduce environmental pollution.It is recommended tha 展开更多
关键词 Agricultural green development Baiyangdian Basin environmental emission threshold partition management
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Toward sustainable food systems: global initiatives and innovations
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作者 xiangwen fan Xiaomeng ZHANG +3 位作者 Xiaofei WU Wenqi MA Zhaohai BAI Lin MA 《Frontiers of Agricultural Science and Engineering》 CSCD 2024年第1期197-209,共13页
A recent UN Sustainable Development Goals(SDGs) analysis indicated a significant regression in the global SDG goal scores, particularly in SDG 2—Zero Hunger. The emissions of environmental pollution caused by meeting... A recent UN Sustainable Development Goals(SDGs) analysis indicated a significant regression in the global SDG goal scores, particularly in SDG 2—Zero Hunger. The emissions of environmental pollution caused by meeting food demands have prompted some countries to intensify their climate change mitigation efforts. These circumstances have introduced significant uncertainty to the future global sustainable food development. Additionally, a notable global challenge is the persistence of hidden hunger, primarily characterized by the insufficient consumption of high-quality animal protein. Addressing this issue would necessitate increased environmental costs to attain high-quality food security. The future food system presents a significant challenge in coordinating food security, food quality and environmental quality. This article presents a comprehensive review and proposes a three-step strategy for future agricultural development based on food security, quality, and environmental aspects. This is a novel food system transfer strategy, as it concurrently addresses both global food security and environmental thresholds. It involves the construction of an efficient food system that operates within the constraints of environmental limits. The objective is to align with global SDG indicators and to maintain natural resource consumption and pollutant emissions within planetary boundaries. 展开更多
关键词 Agricultural green development food system food production optimization transform pathways
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一种基于异构冗余的高可靠性舞台控制架构
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作者 王子涵 张向文 +1 位作者 张帆 何鑫 《演艺科技》 2024年第1期53-58,共6页
为了提高舞台控制架构的可靠性,本文提出一种从操作台、PLC、变频器、网络通讯等全面冗余的控制系统架构,消除了整体系统的单点设备,做到全冗余架构,在任意部位出现故障后,系统均能正常运行,保证演出顺利及人员安全。最后通过模型搭建... 为了提高舞台控制架构的可靠性,本文提出一种从操作台、PLC、变频器、网络通讯等全面冗余的控制系统架构,消除了整体系统的单点设备,做到全冗余架构,在任意部位出现故障后,系统均能正常运行,保证演出顺利及人员安全。最后通过模型搭建与仿真验证,证明了本架构有效提高了舞台控制系统的可靠性。 展开更多
关键词 舞台机械 舞台机械控制系统 冗余设计 异构冗余
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Comparison of indicators for agricultural green development and the Sustainable Development Goals,and mapping the way forward
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作者 Jianjie ZHANG xiangwen fan +3 位作者 Ling LIU Lin MA Zhaohai BAI Wenqi MA 《Frontiers of Agricultural Science and Engineering》 CSCD 2024年第1期69-82,共14页
While agricultural green development(AGD)is highly recognized and has become a national strategy in China,it is imperative to bridge the knowledge gaps between AGD and the UN Sustainable Development Goals(SDGs),and to... While agricultural green development(AGD)is highly recognized and has become a national strategy in China,it is imperative to bridge the knowledge gaps between AGD and the UN Sustainable Development Goals(SDGs),and to evaluate the contribution of AGD to meeting the SDGs.The first aim of this study was to compare the AGD goals and indicators with those of the SDGs so as to identify their relationship.The next aim was to examine the historical evolution of AGD indicators and analyze the gaps between the current status of various indicators and their benchmarks.Limiting factors were identified in China's transition toward AGD.These findings reveal that the indicators of AGD align with those of the SDGs,but have greater specificity to the context in China and are more quantifiable.There has been a significant increase per capita calorie and protein intakes in China,as well as a notable rise in agricultural output per unit of arable land and rural incomes from 1980 to the 2010s.However,these achievements have been accompanied by a high resource use and environmental pollution,highlighting the need for a more sustainable,environmentally responsible agriculture in China. 展开更多
关键词 Agricultural green development sustainable development goals environmental sustainability indicator system optimization pathway
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金樱子不同提取方法提取物体外抑制病毒活性及机制研究 被引量:5
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作者 刘金安 刘相文 +3 位作者 耿巧玉 范路路 李思齐 田景振 《西部中医药》 2020年第1期9-12,共4页
目的:考察金樱子不同提取物对呼吸道合胞病毒(respiratory syncytial virus,RSV)、Ⅰ型单纯性疱疹病毒(herpes simplex virus type 1,HSV-1)的预防、直接杀灭和穿入人喉癌上皮细胞(human larynx carcinoma epithelial cell,Hep-2)感染... 目的:考察金樱子不同提取物对呼吸道合胞病毒(respiratory syncytial virus,RSV)、Ⅰ型单纯性疱疹病毒(herpes simplex virus type 1,HSV-1)的预防、直接杀灭和穿入人喉癌上皮细胞(human larynx carcinoma epithelial cell,Hep-2)感染的阻断作用。方法:运用体外抗病毒实验CPE法结合CCK-8染色法,以EC50、TC50及TI值作为指标,探讨金樱子甲醇、丙醇提取液对RSV、HSV-1及其穿入Hep-2感染的体外抑制活性及作用机制。结果:金樱子甲醇冷浸提取物对RSV和HSV-1的TI值分别为15.958、7.814;金樱子甲醇超声提取物对RSV和HSV-1的TI值分别为10.455、15.221;丙酮冷浸提取物对RSV的TI值为7.191;丙酮超声提取物对RSV的TI值为6.648。金樱子甲醇冷浸提取物在阻断HSV-1穿入后感染中TI值为5.650;金樱子甲醇超声提取物在阻断HSV-1穿入后感染中TI值为3.185。结论:金樱子提取物在体外能够抑制RSV、HSV-1对Hep-2细胞的感染,且金樱子的甲醇提取物作用机制复杂,有待进一步探究。 展开更多
关键词 金樱子 甲醇提取液 丙醇提取液 抗病毒 呼吸道合胞病毒 Ⅰ型单纯性疱疹病毒 人喉癌上皮细胞
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基于GA-BP神经网络对控制棒水力缓冲器的性能预测和结构参数优化
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作者 张相文 范晨光 +2 位作者 何安 武闯 杨宇静 《核动力工程》 EI CAS CSCD 北大核心 2023年第6期162-169,共8页
为通过遗传算法(GA)改进的反向传播(BP)神经网络模型预测控制棒组件水力缓冲器的缓冲性能,并实现结构参数优化,本研究对一种特定的控制棒组件水力缓冲器静水中的落棒进行模拟试验,变换试验可调参数,设置不同的试验工况,获取了大量的试... 为通过遗传算法(GA)改进的反向传播(BP)神经网络模型预测控制棒组件水力缓冲器的缓冲性能,并实现结构参数优化,本研究对一种特定的控制棒组件水力缓冲器静水中的落棒进行模拟试验,变换试验可调参数,设置不同的试验工况,获取了大量的试验数据,通过GA-BP神经网络对控制棒组件落棒过程的最大冲击力进行预测,并构建优化数学模型,使用非线性规划函数(fmincon)进行求解,获得更优的结构参数组合。结果表明:GA-BP神经网络模型相较于BP神经网络模型具有更高的预测精度,通过fmincon函数可以实现对控制棒组件最大冲击力优化数学模型的快速求解。因此,本文的优化方法可为水力缓冲器的结构优化设计提供一定的参考。 展开更多
关键词 控制棒水力缓冲器 缓冲性能试验 最大冲击力 GA-BP神经网络 参数优化
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STRATEGIES FOR A LOW-CARBON FOOD SYSTEM IN CHINA
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作者 Xinpeng JIN xiangwen fan +2 位作者 Yuanchao HU Zhaohai BAI Lin MA 《Frontiers of Agricultural Science and Engineering》 CSCD 2023年第2期167-182,共16页
In China,there has been insufficient study of whole food system greenhouse gas(GHG)accounting,which limits the development of mitigation strategies and may preclude the achievement of carbon peak and carbon neutrality... In China,there has been insufficient study of whole food system greenhouse gas(GHG)accounting,which limits the development of mitigation strategies and may preclude the achievement of carbon peak and carbon neutrality goals.The paper presents the development of a carbon extension of NUFER(NUtrient flows in Food chain,Environment and Resources use model),a food system GHG emission accounting model that covers land use and land-use change,agricultural production,and post-production subsectors.The spatiotemporal characteristics of GHG emissions were investigated for the Chinese food system(CFS)from 1992 to 2017,with a focus on GHG emissions from the entire system.The potential to achieve a low-carbon food system in China was explored.The net GHG emissions from the CFS increased from 785Tg CO_(2)equivalent(CO_(2)-eq)in 1992 to 1080 Tg CO_(2)-eq in 2017.Agricultural activities accounted for more than half of the total emissions during the study period,while agricultural energy was the largest contributor to the GHG increase.In 2017,highest emitting regions were located in central and southern China(Guangdong and Hunan),the North China Plain(Shandong,Henan and Jiangsu)and Northeast China(Heilongjiang and Inner Mongolia)and contributed to over half of the total GHG emissions.Meanwhile,Xinjiang,Qinghai and Tibet are shown as carbon sink areas.It was found that foodsystem GHG emissions could be reduced to 355 Tg CO_(2)-eq,where enhancing endpoint mitigation technologies,transforming social-economic and diet conditions,and increasing agricultural productivities can contribute to 60%,25%and 15%,respectively.Synergistic mitigation effects were found to exist in agricultural activities. 展开更多
关键词 greenhouse gas emissions food system life cycle assessment environmental inputoutput analysis mitigation strategies
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阿托伐他汀对2型糖尿病患者颈动脉粥样硬化的作用 被引量:4
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作者 吴艳 张怀国 +6 位作者 梁存福 徐向文 范海影 陶蕊 王玲玲 李斌 李树法 《中华临床医师杂志(电子版)》 CAS 2018年第3期129-134,共6页
目的探讨阿托伐他汀治疗对2型糖尿病患者糖代谢、脂代谢、炎症因子水平及颈动脉粥样硬化的作用。方法选取临沂市人民医院2015年1月至2016年12月收治的2型糖尿病患者196例,按治疗方式的不同随机分为对照组与阿托伐他汀组,各98例。2组患... 目的探讨阿托伐他汀治疗对2型糖尿病患者糖代谢、脂代谢、炎症因子水平及颈动脉粥样硬化的作用。方法选取临沂市人民医院2015年1月至2016年12月收治的2型糖尿病患者196例,按治疗方式的不同随机分为对照组与阿托伐他汀组,各98例。2组患者均予降糖、降压及阿司匹林治疗,阿托伐他汀组在此基础上加用阿托伐他汀20 mg治疗,均持续治疗6个月。采用t检验比较2组患者治疗前后糖代谢指标[空腹血糖(FPG)、糖化血红蛋白(Hb A1c)、空腹胰岛素(FINS)、胰岛素抵抗指数(HOMA-IR)]、脂代谢[总胆固醇(TC)、三酰甘油(TG)、低密度脂蛋白胆固醇(LDL-C)、高密度脂蛋白胆固醇(HDL-C)]、炎症因子[C反应蛋白(CRP)、白细胞介素6(IL-6)、肿瘤坏死因子α(TNF-α)、细胞间黏附分子-1(ICAM-1)、血管细胞黏附分子-1(VCAM-1)、内皮细胞选择蛋白(Selectin)]水平及颈动脉粥样硬化指标[颈动脉内中膜厚度(IMT)、斑块厚度、斑块大小、斑块数量)的差异,采用Logistic回归分析分析IMT的影响因素。结果治疗后,阿托伐他汀组的糖代谢指标FPG、Hb A1c、FINS、HOMA-IR水平与对照组相比差异均无统计学意义[(6.42±1.21)mmol/L vs(6.27±1.05)mmol/L,t=0.406,P=0.572;(6.21±0.65)%vs(6.08±0.73)%,t=0.662,P=0.339;(13.04±1.21)%vs(12.83±1.15)%,t=0.316,P=0.606;(3.75±0.27)vs(3.64±0.35),t=0.283,P=0.692)];脂代谢指标TC、TG、LDL-C的水平低于对照组,HDL-C的水平高于对照组,差异具有统计学意义[(3.18±0.33)vs(4.76±0.39),t=2.738,P=0.009;(1.69±0.14)vs(2.13±0.31),t=3.012,P=0.003;(1.74±0.27)vs(3.08±0.39),t=3.974,P=0.001;(1.26±0.21)vs(1.04±0.15),t=2.458,P=0.014)];炎症因子CRP、IL-6、TNF-α、ICAM-1、VCAM-1、Selectin的水平低于对照组,差异具有统计学意义[(0.83±0.09)vs(0.92±0.11),t=2.576,P=0.036;(1.83±0.25)vs(2.32±0.36),t=3.119,P=0.025;(33.83±4.15)vs(41.92±6.11),t=3.102,P=0.029;(198.83±14.15)vs(210.92±15.11),t=2.583,P=0.035;(457.83±41.15)vs(501.92±38.11),t= 展开更多
关键词 2型糖尿病 阿托伐他汀 糖脂代谢 炎症因子水平 颈动脉粥样硬化
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云南省番茄莴苣褪绿病毒分子检测及遗传进化分析 被引量:2
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作者 冯丽肖 胡荣 +7 位作者 卜姗 张德咏 罗香文 李凡 丁铭 张卓 张松柏 刘勇 《园艺学报》 CAS CSCD 北大核心 2022年第1期141-147,共7页
采集了77份云南省疑似感染莴苣褪绿病毒(lettuce chlorosis virus,LCV)的番茄样本,采用特异性反转录PCR扩增LCV次要外壳蛋白基因(minor coatprotein,CPm)近全长序列,常规Sanger测序法测定相应片段序列,并对其进行遗传进化分析。结果表明... 采集了77份云南省疑似感染莴苣褪绿病毒(lettuce chlorosis virus,LCV)的番茄样本,采用特异性反转录PCR扩增LCV次要外壳蛋白基因(minor coatprotein,CPm)近全长序列,常规Sanger测序法测定相应片段序列,并对其进行遗传进化分析。结果表明,LCV特异性反转录PCR扩增得到与预期大小(1.38 kb)—致的特异性条带;采集的77份番茄样本中LCV检出率为12.99%。测定的LCV CPm;发育分析表明,所有LCV分离物可分为3个亚簇,具有明显的地域特性,其中LCV云南分离物与中国其他地区LCV分离物聚为一亚簇,来自美洲和欧洲分离物分别聚为一个簇。遗传进化分析表明,LCV云南分离物YN58有1个重组事件,序列中嘧啶(C/T)替换率最高(25.25),呈现独立进化、加速扩展趋势。这是在云南省首次报道发现LCV。 展开更多
关键词 番茄 莴苣褪绿病毒 分子检测 系统发育分析 进化
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China requires region-specific manure treatment and recycling technologies 被引量:3
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作者 Zhaohai Bai Xuan Wang +5 位作者 Xiaofei Wu Weishuai Wang Ling Liu Xiaohang Zhang xiangwen fan Lin Ma 《Circular Agricultural Systems》 2021年第1期1-8,共8页
Heterogenous distribution of crops,feed and livestock across China has halted the circulation of nutrients within the agricultural system and is responsible for massive nutrient losses[1,2].Generated livestock manure ... Heterogenous distribution of crops,feed and livestock across China has halted the circulation of nutrients within the agricultural system and is responsible for massive nutrient losses[1,2].Generated livestock manure exceeded optimal crop requirements in 30%and 50%of over 2300 studied counties when there was improved recycling of nitrogen(N)and phosphorus(P)in the food chain,repectively[2].Most of these counties are located in southern and coastal areas,whereas there is a deficit of livestock manure in northern and western China.Such heterogenous distribution of crop-livestock production led to 4.0 Tg manure N and 0.9 Tg manure P[2],which are economically impossible to recycle and will end up in the surrounding environment.In addition,about 40%of feed protein consumed by domestic livestock production relied on importation,putting China’s livestock production supply at high risk in the post pandemic world[3].Hence,China is facing the twin issues of too many manure nutrients but too little feed nutrients simultaneously. 展开更多
关键词 MANURE crops LIVESTOCK
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Passive patterned polymer dispersed liquid crystal transparent display 被引量:1
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作者 Jing Yan xiangwen fan +3 位作者 Yifan Liu Ying Yu Yuming fang Ruo-Zhou Li 《Chinese Optics Letters》 SCIE EI CAS CSCD 2022年第1期155-159,共5页
A patterned polymer dispersed liquid crystal transparent display using one-time UV exposure is demonstrated.The device is fabricated by exposing the cell with a uniform UV light through a mask with selective attenuati... A patterned polymer dispersed liquid crystal transparent display using one-time UV exposure is demonstrated.The device is fabricated by exposing the cell with a uniform UV light through a mask with selective attenuation of the UV light.The voltage-transmittance response of the device is different for the corresponding regions.Thus,three different states of total scattering,patterned transparent,and total transparent can be realized by controlling the applied voltages.The proposed device used in shutter mode as smart windows and in projected display mode is demonstrated,which shows great potential for smart windows with customized patterns or logos and has potential application in the field of projected transparent displays. 展开更多
关键词 polymer dispersed liquid crystal transparent display
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Copper-catalyzed diversified annulations betweenα-diketones and alkynylα-diketones
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作者 xiangwen Kong fang Yu +5 位作者 Shengtong Niu fan Gong Shuang Yang Jinggong Liu Benlong Luo Xinqiang fang 《Chinese Chemical Letters》 SCIE CAS CSCD 2022年第6期2997-3002,共6页
Copper-catalyzed divergent annulations betweenα-diketones and alkynylα-diketones have been achieved,delivering a series of highly functionalized and biologically important cis-hexahydro-2Hcyclopenta[b]furan(HCPF)and... Copper-catalyzed divergent annulations betweenα-diketones and alkynylα-diketones have been achieved,delivering a series of highly functionalized and biologically important cis-hexahydro-2Hcyclopenta[b]furan(HCPF)and 2-hydroxydihydrofuran-3(2H)-one(HDFO)products with high levels of stereoselectivity under identical conditions.The protocol features the use of earth-abundant copper catalyst,mild conditions,shortening synthetic routes in constructing different molecular frameworks,and reducing the corresponding possible waste production.The substituents of the nucleophilicα-diketones play crucial roles in switching the reaction pathways. 展开更多
关键词 Copper catalysis α-Diketones Diversified annulations Substituents-controlled reactivities Atom economy
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一种智能化媒资检索系统的研究 被引量:1
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作者 关力 张向问 +1 位作者 张帆 郝欣伟 《信息技术与网络安全》 2018年第4期52-54,共3页
随着信息产业的发展,信息、数据的传输存储已经遍布每个领域。在图书馆、档案室、电视台等单位每天都会产生大量数据,并将数据存放于纸张、磁带或光盘等介质(统称"媒资")中。为了实现大量信息的快速、自动检索,提出了一种媒... 随着信息产业的发展,信息、数据的传输存储已经遍布每个领域。在图书馆、档案室、电视台等单位每天都会产生大量数据,并将数据存放于纸张、磁带或光盘等介质(统称"媒资")中。为了实现大量信息的快速、自动检索,提出了一种媒资智能检索系统方案并实施。该系统实现了大量信息中媒资的自动检索、快速定位,改变了传统的专员管理模式,提高了检索效率,降低了人工成本。 展开更多
关键词 媒资 智能检索 效率
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Catalytic chemodivergent annulations betweenα-diketones and alkynylα-diketones
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作者 xiangwen Kong fang Yu +5 位作者 Zhizhou Chen fan Gong Shuang Yang Jinggong Liu Benlong Luo Xinqiang fang 《Science China Chemistry》 SCIE EI CSCD 2021年第6期991-998,共8页
Four types of unprecedented and chemodivergent reactions betweenα-diketones and alkynylα-diketones have been achieved under the catalysis of phosphine and Br?nsted base,respectively,leading to the rapid construction... Four types of unprecedented and chemodivergent reactions betweenα-diketones and alkynylα-diketones have been achieved under the catalysis of phosphine and Br?nsted base,respectively,leading to the rapid construction of four different classes of biologically important but synthetically challenging molecular scaffolds including 2-hydroxyfuran-3(2H)-ones,4-hydroxy-2-oxabicyclo[2.2.1]heptan-3-ones,1,3-diaryl cyclobutanes,and 4-(furan-2(3H)-ylidene)cyclopent-2-enones.The formation of the products includes two novel rearrangement processes,and further transformations on the products can be easily achieved to deliver value-added substances such as highly functionalized cyclopentanes.Moreover,the 2-hydroxyfuran-3(2H)-one products display promising photophysical properties such as green luminescence under UV light and aggregation-induced emission effect,showing the practical application value of this work.The great potential ofα-diketones in both synthetic chemistry and material science has been unambiguously demonstrated. 展开更多
关键词 chemodivergent reaction cascade annulation phosphine catalysis rearrangement reaction fluorescent material
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五层纳米SiO_2-Al_2O_3/聚酰亚胺复合薄膜的制备及性能 被引量:6
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作者 杨瑞宵 陈昊 +2 位作者 王相文 赵伟 范勇 《复合材料学报》 EI CAS CSCD 北大核心 2018年第5期1050-1058,共9页
采用浸胶法制备了一系列SiO_2-Al_2O_3/聚酰亚胺(SiO_2-Al_2O_3/PI)五层耐电晕薄膜AmAnPAnAm,其中中间层(P)为纯PI薄膜,外层(Am)、次外层(An)分别为SiO_2-Al_2O_3掺杂不同质量分数的纳米SiO_2-Al_2O_3/PI薄膜。采用TEM、FTIR、宽频介电... 采用浸胶法制备了一系列SiO_2-Al_2O_3/聚酰亚胺(SiO_2-Al_2O_3/PI)五层耐电晕薄膜AmAnPAnAm,其中中间层(P)为纯PI薄膜,外层(Am)、次外层(An)分别为SiO_2-Al_2O_3掺杂不同质量分数的纳米SiO_2-Al_2O_3/PI薄膜。采用TEM、FTIR、宽频介电谱仪、电导电流测试仪、耐电晕测试仪、介电强度测试仪和拉伸实验机对五层纳米复合PI耐电晕薄膜的微观结构、介电性能和力学性能进行了表征和测试。结果表明,SiO_2-Al_2O_3/PI复合薄膜掺杂层形成了分布均匀的有机/无机复合结构;SiO_2-Al_2O_3纳米粒子的保护作用是影响复合材料耐电晕性能的主要因素,复合薄膜A32A16PA16A32的耐电晕寿命最大,为23.4h;外层掺杂量对五层SiO_2-Al_2O_3/PI复合材料的介电强度影响较大,复合薄膜A20A28PA28A20的介电强度最大,为302.3kV/mm;通过对五层复合结构的设计,可以在兼顾材料力学性能的同时,提高其耐电晕寿命和介电强度。 展开更多
关键词 复合薄膜 聚酰亚胺(PI) SiO2-Al2O3纳米粒子 多层结构 介电性能 耐电晕
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基于SVDD和改进K-Means的变压器故障诊断模型
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作者 谢旭钦 刘泉辉 +3 位作者 赵湘文 张清松 林剑雄 张帆 《计算技术与自动化》 2024年第2期30-34,共5页
变压器状态对于智能配电房的安全稳定运行具有重要意义。为实现对变压器故障的准确诊断,在变压器油中溶解气体分析(DGA)的基础上,提出了一种联合使用支持向量数据描述(SVDD)和改进K-Means聚类的变压器故障诊断方法。首先利用SVDD构造闭... 变压器状态对于智能配电房的安全稳定运行具有重要意义。为实现对变压器故障的准确诊断,在变压器油中溶解气体分析(DGA)的基础上,提出了一种联合使用支持向量数据描述(SVDD)和改进K-Means聚类的变压器故障诊断方法。首先利用SVDD构造闭合分类曲面实现“正常”和“故障”两类判断,然后对“故障”类样本进行K-Means聚类分析,自动将其划分为低能放电、中低温过热、高能放电、高温过热和局部放电5种故障类型,同时针对K-Means初始聚类中心选取难题,提出局部密度概念自动确定K-Means初始聚类中心,提升聚类性能。最后利用变压器故障真实数据开展实验,结果表明,相较于支持向量机(SVM)和BP神经网络模型,所提方法的故障诊断准确率分别提升9.8%和8%。 展开更多
关键词 智能配电房 变压器故障诊断 油中溶解气体分析 支持向量数据描述 多分类器联合
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双机重联技术在井下直线往返式运输平巷中的应用
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作者 凌敏 朱超 +2 位作者 孔祥文 许正辉 樊伟 《黄金》 CAS 2020年第2期50-52,61,共4页
矿井机车运输效率直接影响矿山的生产效率。以会泽矿业分公司井下运输为工程背景,分析了双机重联技术在井下直线往返式运输平巷中应用面临的问题,提出了技术改造措施。围绕遥控装矿、单人操作串车、自动卸矿3个环节,结合现场工况条件,... 矿井机车运输效率直接影响矿山的生产效率。以会泽矿业分公司井下运输为工程背景,分析了双机重联技术在井下直线往返式运输平巷中应用面临的问题,提出了技术改造措施。围绕遥控装矿、单人操作串车、自动卸矿3个环节,结合现场工况条件,优化调整平巷架空线、轨道等硬件设施,增设遥控控制、无线通信技术等设备设施。通过系统的优化改造,实现了双机重联技术在井下直线往返式运输平巷中的成功应用,最大限度地发挥了机车牵引运行效率,有效降低了运输成本。 展开更多
关键词 双机重联 运输平巷 直线往返式 混合平巷 遥控装矿 单人操作
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一种自动获取CAN网络拓扑关系的方法研究
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作者 张向文 张帆 李向阳 《微型机与应用》 2017年第10期74-76,80,共4页
基于控制系统智能化水平日益增长的背景,快速自动识别出CAN总线网络拓扑关系的需求日益突出,采用在CAN总线传统网络架构中增加中间层的措施,结合CAN总线网络链路动态分离的机制,设计了详细的切换电路,介绍了电路的工作原理及整个系统的... 基于控制系统智能化水平日益增长的背景,快速自动识别出CAN总线网络拓扑关系的需求日益突出,采用在CAN总线传统网络架构中增加中间层的措施,结合CAN总线网络链路动态分离的机制,设计了详细的切换电路,介绍了电路的工作原理及整个系统的工作原理,明确了总线数据的处理流程、方法,实现了CAN总线网络拓扑关系的快速自动识别,为后续相关技术的应用奠定了基础。 展开更多
关键词 CAN总线 网络拓扑 编组 逻辑序列 动态分离
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