检索结果-南通市图书馆

秦岭北麓地区CO_(2)和水汽湍流输送实验研究

在线全文

学校读者我要写书评

暂无评论

中国环境科学 2024年第5期44卷 2407-2417页

作者：彭艳赵奎锋张璐张宏昇李星敏陕西省气象科学研究所秦岭和黄土高原生态环境气象重点实验室陕西西安710016 陕西省气象局秦岭和黄土高原生态环境气象重点实验室陕西西安710016 北京大学物理学院大气与海洋科学系气候与海-气实验室北京100871

利用中国气象局秦岭气溶胶与云微物理野外科学试验基地长安站2021年4月~2022年3月涡动相关系统观测资料,结合气象观测资料,研究了秦岭北麓城郊过渡带近地面大气CO_(2)、H_(2)O浓度、蒸发量以及湍流通量演变特征,并讨论了气象要素对碳通... 详细信息

利用中国气象局秦岭气溶胶与云微物理野外科学试验基地长安站2021年4月~2022年3月涡动相关系统观测资料,结合气象观测资料,研究了秦岭北麓城郊过渡带近地面大气CO_(2)、H_(2)O浓度、蒸发量以及湍流通量演变特征,并讨论了气象要素对碳通量的影响.结果表明:观测时段内CO_(2)小时浓度年均值为(404.4±27.9)×10^(-6),与瓦里关大气背景观测站和全球背景观测站CO_(2)年均值浓度水平相当,水汽小时浓度年均值为9.44g/m^(3),年总蒸发量为1321.5mm;CO_(2)、水汽浓度和蒸发量均存在显著的月、季节变化特征;CO_(2)和水汽通量存在明显的日、月和季节变化,全年白天均表现为较强的碳吸收,观测时段内CO_(2)总吸收量约为-3047g/m^(2);夜间表现为碳排放,观测时段内总排放量约为2631g/m^(2);气温、土壤温度、相对湿度和风速的变化均会对区域内CO_(2)通量产生影响,温度升高会增加区域内植被的固碳能力;白天CO_(2)通量负值多出现在西风条件下,农田和植被覆盖率较大的区域为CO_(2)通量的主要贡献区域;夜间CO_(2)通量正值主要来自于植被、土壤呼吸作用和人类活动排放的贡献.总体而言,秦岭北麓城郊过渡带呈现较为明显的碳汇属性,实验时段内CO_(2)的净吸收量约为-416g/m^(2).

关键词： CO_(2)通量秦岭北麓城郊过渡带涡动相关气象因子

NEW GROWTH DRIVER--New urbanization to expand investment and consumption

在线全文

学校读者我要写书评

暂无评论

Beijing Review 2020年第34期63卷 16-17页

作者： feng kui the China Center for Urban Development

At a meeting on July 30,the Political Bureau of the Central Committee of the Communist Party of China(CPC)proposed that investment and consumption demand should be driven through new urbanization projects.Normally.

关键词： investment urbanization consumption

Preparation and Microstructure Evaluation of Directionally Solidified Nd-Fe-B Ingots by Electromagnetic Cold Crucible

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research(International) 2012年第S1期19卷 237-242页

作者： DING Hong-sheng feng kui WANG Yong-zhe CHEN Rui-run GUO Jing-jie National Key Laboratory for Precision Hot Processing of Metals School of Materials Science and EngineeringHarbin Institute of Technology

In this paper Nd-Fe-B ingots with hyper-peritectic composition were prepared through continuous and directional solidification by a novel electromagnetic cold crucible approach.A group of experiments were carried out in order to investigate the effects of input power and withdrawal velocity on the microstructure and growth orientation of Nd-Fe-B phases.It was found that the peritectic Nd;Fe;B phase grows with a planar interface at lower withdrawal velocity and changed into the dendritic interface at higher withdrawal velocity.The result was explained by the theory of constitutional supercooling.Meanwhile the volume fraction of ferromagnetic T;phase was found to be increased first and then decreased with the increasing of withdrawal velocity during the growth process of the ingots.

关键词： electromagnetic cold crucible directional solidification Nd-Fe-B structure ferromagnetic phase

Fat-to-muscle Ratio: A New Anthropometric Indicator for Predicting Metabolic Syndrome in the Han and Bouyei Populations from Guizhou Province, China

在线全文

学校读者我要写书评

暂无评论

Biomedical and Environmental Sciences 2018年第4期31卷 261-271页

作者： XU Ke ZHU Hui Juan CHEN Shi CHEN Lu WANG Xin ZHANG Li Yuan PAN Li WANG Li feng kui WANG Ke DONG Fen WANG Ding Ming YU Yang Wen PAN Hui SHAN Guang Liang Key Laboratory of Endocrinology of National Health and Family Planning Commission Department of Endocrinology Peking Union Medical College Hospital Chinese Academy of Medical Science and Peking Union Medical College Graduate School Hebei North University Department of Epidemiology and Biostatistics Institute of Basic Medical Sciences Chinese Academy of Medical Sciences School of Basic Medicine Peking Union Medical College National Office for Maternal and Child Health Surveillance of China Department of Obstetrics Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University) Ministry of Education West China Second University Hospital Sichuan University Institute of Clinical Medical Sciences China-Japan Friendship Hospital Institute for Infection Guizhou Provincial Center for Disease Control and Prevention

Objective To investigate the prevalence and possible factors influencing metabolic syndrome in people from Guizhou Province and to explore the predictive value of the fat-to-muscle ratio in diagnosing metabolic syndrome. Methods A multistage stratified sampling method was used in this cross-sectional study of 20-80 years old Han and Bouyei populations from Guizhou Province, southwestern China, from October-December 2012. The study included 4,553 cases of metabolic syndrome, that was defined according to 2005 International Diabetes Federation criteria. The receiver operating characteristic curve was used for determining the sensitivity, specificity, and predictive ability of the fat-to-muscle ratio for the diagnosis of metabolic syndrome. Results The age-standardized prevalence of metabolic syndrome was 11.38%（men： 9.76%; women： 12.72%） for Han and 4.78%（men： 4.43%; women： 5.30%） for Bouyei populations. In Guizhou Province, the cut-off value for the men fat-to-muscle ratio was 0.34, the area under the curve was 0.95, and the sensitivity and specificity were 0.94 and 0.85, respectively. The cut-off value for the women fat-to-muscle ratio was 0.55, the area under the curve was 0.91, and the sensitivity and specificity were 0.93 and 0.79, respectively. Conclusion The fat-to-muscle ratio is highly predictive of metabolic syndrome in Guizhou Province, and a useful reference indicator.

关键词： Metabolic syndrome Anthropometric indicator Muscle Fat Fat-to-muscle ratio

在线全文

学校读者我要写书评

暂无评论

基于视觉的交通场景目标检测与跟踪技术研究

计算机仿真 2024年第4期41卷 156-160,283页

作者：张涌周爱博黄林雄赵奉奎南京林业大学汽车与交通工程学院江苏南京210037

针对通用目标检测算法在交通场景下检测多目标时存在的小目标漏检和误检问题,提出了一种适用于交通场景下的目标检测与跟踪算法。基于K-means++聚类算法计算出适合交通场景下目标检测的锚定框(Anchor Box)和深度可分离卷积的思想优化目... 详细信息

针对通用目标检测算法在交通场景下检测多目标时存在的小目标漏检和误检问题,提出了一种适用于交通场景下的目标检测与跟踪算法。基于K-means++聚类算法计算出适合交通场景下目标检测的锚定框(Anchor Box)和深度可分离卷积的思想优化目标检测算法。其次,利用匈牙利匹配将卡尔曼滤波的预测值和目标检测的实际值相关联匹配,以实现目标跟踪。实验结果证明,改进后的目标检测与跟踪算法较原始算法在mAP方面提升了2.3%,达到了99.13%;速度提升了20%,达到了30帧/秒,对交通场景下的特定目标均实现了准确检测跟踪,保持了较好的实时性。

关键词：目标检测目标跟踪卡尔曼滤波匈牙利匹配

Recovery of cyanophycin granule polypeptide from activated sludge: carbon source dependence and aggregation-induced luminescence characteristics

在线全文

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2024年第2期18卷 25-34页

作者： kui Zou Hongyuan Liu Bo feng Taiping Qing Peng Zhang College of Environment and Resources Xiangtan UniversityXiangtan 411105China

In the sewage treatment process,facilitating the conversion of pollutants into value-added resources holds great potential for reducing the amount of greenhouse gas emissions and promoting economic circulation.Cyanophycin granule polypeptide(CGP),a recently discovered high value-added biopolymer present in activated sludge,has provided new avenues for the recovery of resources.However,the mechanisms that regulate CGP synthesis and the characteristics of this biopolymer in activated sludge remain unclear thus far.This study investigated the synthesis of CGP,polyhydroxyalkanoates(PHA),and alginate-like exopolysaccharides(ALE)in various microbial aggregates under different carbon sources feeding conditions.Our results showed that the CGP yields was superior that of PHA and ALE when subjected to identical carbon source feeding conditions.Furthermore,biofilm was more conducive to CGP accumulation than floc sludge.Compared with glucose and methanol,sodium acetate significantly enriched the CGP synthetase-encoding gene(cphAabundance=~17419),resulting in the highest CGP yield(average 107.1 mg/g MLSS)in both biofilm and floc sludge.This study is the first to reported the characteristic fluorescence of CGP(Ex/Em=~360/450 nm)caused by the aggregated luminescence of arginine on the side chains.Overall,this study highlights the potential application of CGP as a fluorescent material and offers insights into CGP recovery from activated sludge in wastewater treatment plants.

关键词： Cyanophycin Polyhydroxyalkanoate Alginate-like exopolysaccharides Bioresource recovery Aggregation-induced luminescence

检测方法对20CrNiMoH钢奥氏体晶粒度的影响

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

热处理技术与装备 2024年第1期45卷 53-55页

作者：董凤奎黄山刘年富钟芳华宝武杰富意特殊钢有限公司广东韶关512123 桂林福达齿轮有限公司广西桂林541199

奥氏体晶粒度是衡量钢材质量的一个重要指标,研究了奥氏体晶粒度显示方法对20CrNiMoH渗碳齿轮钢奥氏体晶粒度检测结果的影响。结果表明,氧化法和直接淬硬法检测的奥氏体晶粒度差别较小,渗碳法检测的奥氏体晶粒比氧化法和直接淬硬法低0.2... 详细信息

奥氏体晶粒度是衡量钢材质量的一个重要指标,研究了奥氏体晶粒度显示方法对20CrNiMoH渗碳齿轮钢奥氏体晶粒度检测结果的影响。结果表明,氧化法和直接淬硬法检测的奥氏体晶粒度差别较小,渗碳法检测的奥氏体晶粒比氧化法和直接淬硬法低0.2~0.3级,模拟渗碳法检测奥氏体晶粒度存在混晶现象。对造成模拟渗碳法出现混晶的原因进行了分析,并给出了改进措施,确保使用模拟渗碳法检测奥氏体晶粒度仍没有混晶现象出现。

关键词： 20CrNiMoH钢奥氏体晶粒度混晶

Self-assembled donor-acceptor hole contacts for inverted perovskite solar cells with an efficiency approaching 22%: The impact of anchoring groups

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2022年第5期31卷 87-95页

作者： Qiaogan Liao Yang Wang Zilong Zhang Kun Yang Yongqiang Shi kui feng Bolin Li Jiachen Huang Peng Gao Xugang Guo Department of Materials Science and Engineering Guangdong Provincial Key Laboratory of Functional Oxide Materials and DevicesSouthern University of Science and Technology(SUSTech)Shenzhen 518055GuangdongChina College of Materials Fujian Key Laboratory of Advanced MaterialsXiamen UniversityXiamen 361005FujianChina CAS Key Laboratory of Design and Assembly of Functional Nanostructures Fujian Provincial Key Laboratory of NanomaterialsFujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002FujianChina School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001HeilongjiangChina

Self-assembled molecules(SAMs) have shown great potential in replacing bulk charge selective contact layers in high-performance perovskite solar cells(PSCs) due to their low material consumption and simple processing. Herein, we design and synthesize a series of donor-acceptor(D-A) type SAMs(MPA-BTCA, MPA-BT-BA, and MPA-BT-RA, where MPA is 4-methoxy-N-(4-methoxyphenyl)-N-phenylaniline;BT is benzo[c][1,2,5]-thiadiazole;CA is 2-cyanoacrylic acid, BA is benzoic acid, RA is rhodanine-3-propionic acid) with distinct anchoring groups, which show dramatically different properties. MPA-BTCA with CA anchoring groups exhibited stronger dipole moments and formed a homogeneous monolayer on the indium tin oxide(ITO) surface by adopting an upstanding self-assembling mode. However, the MPA-BT-RA molecules tend to aggregate severely in solid state due to the sp~3 hybridization of the carbon atom on the RA group, which is not favorable for achieving a long-range ordered self-assembled layer.Consequently, benefiting from high dipole moment, as well as dense and uniform self-assembled film,the device based on MPA-BT-CA yielded a remarkable power conversion efficiency(PCE) of 21.81%.Encouragingly, an impressive PCE approaching 20% can still be obtained for the MPA-BT-CA-based PSCs as the device area is increased to 0.80 cm^(2). Our work sheds light on the design principles for developing hole selecting SAMs, which will pave a way for realizing highly efficient, flexible, and large-area PSCs.

关键词： Self-assembled molecules Donor-acceptor backbones Hole contacts Perovskite solar cells Anchoring groups

在线全文

学校读者我要写书评

暂无评论

山东省聊城市梨产业发展分析

北方果树 2024年第1期 62-65页

作者：何子顺许以太赵永飞李炎冯俊奎聊城市农业科学院山东聊城252000 冠县林业综合服务中心山东冠县252500 聊城市林业发展中心山东聊城252000 山东冠县梨园生态旅游有限公司山东冠县252500

为推进聊城市梨产业发展,作者介绍了聊城市梨产业现状,从栽培历史、生产水平、品种变化、区域分布和成熟早等方面阐述梨产业的优势,从产业组织化程度、劳动力成本、品种更新和配套建设等方面分析面临的挑战,从规模、管理和产业变化方面... 详细信息

为推进聊城市梨产业发展,作者介绍了聊城市梨产业现状,从栽培历史、生产水平、品种变化、区域分布和成熟早等方面阐述梨产业的优势,从产业组织化程度、劳动力成本、品种更新和配套建设等方面分析面临的挑战,从规模、管理和产业变化方面分析发展趋势,提出今后发展思路,以期增加梨生产效益,延长产业链,做强聊城市梨产业。

关键词：聊城梨现状发展趋势思路