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Influence of Nostoc entophytum and Tetracystis sp. on Winter Survival of Rapeseed 预览
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作者 Jacint Toth Istvan Gergely +1 位作者 Zoltan Berzsenyi Vince Ordog 《农业科学与技术:B》 2019年第4期251-271,共21页
Bioassay results proved that several microalgae strains of the Mosonmagyaróvár Algal Culture Collection (MACC) enhanced plant growth, due to their hormone content and other secondary metabolites. The aim of ... Bioassay results proved that several microalgae strains of the Mosonmagyaróvár Algal Culture Collection (MACC) enhanced plant growth, due to their hormone content and other secondary metabolites. The aim of the current research was to improve autumn growth and winter survival of rapeseed (Brassica napus L.) by treatment with two microalgae strains selected by bioassay results. Experimental plots were set up in Mosonmagyaróvár in 2010 and 2013. Winter rapeseed hybrid (B. napus L. cv. Orlando) plants were treated in 4-6 leaves stage with 0.3 g/L and 1 g/L suspensions of MACC-612 Nostoc entophytum Bornet & Flahault and MACC-430 Tetracystis sp. in middle of October. After the treatments, the following parameters were recorded: chlorophyll-a and b, carotenoid, dry matter content of leaves, average amount of autumn foliage, diameter of root collar, length of shoot tips, fresh and dry weight of root, and number of plants in autumn and spring. Both microalgae treatments significantly increased pigment concentration and dry matter content of leaves, number of fully grown leaves (13%-46%) and dry root weight (16%-36%). Treatments with 0.3 g/L and 1 g/L MACC-612 suspensions increased the length of shoot apices by 14%-18% and 25%-35%, respectively. Number of overwintered control plants decreased significantly in both years (31%), but there was no decrease in parcels treated with 1 g/L of MACC-612 and MACC-430. Microalgae treatments could increase plant growth and survival, which contributed to the significant increase of thousand seed weight (18%-25%) and total yield (by 10%-24%). 展开更多
关键词 MICROALGAE photosynthetic pigments WINTER OILSEED RAPE WINTER survival
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天然气消费结构多目标优化分配模型 预览
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作者 闫庆友 秦超 《天然气工业》 EI CAS CSCD 北大核心 2019年第6期156-164,共9页
近年来冬季供暖期天然气消费需求持续旺盛,供需形势较为严峻,天然气紧缺又造成燃气机组(电网重要的调峰电源)的调峰能力无法有效发挥,严重制约了风电消纳能力。如何在冬季天然气供应紧张时期,考虑天然气的各类用途,实现天然气的合理分配... 近年来冬季供暖期天然气消费需求持续旺盛,供需形势较为严峻,天然气紧缺又造成燃气机组(电网重要的调峰电源)的调峰能力无法有效发挥,严重制约了风电消纳能力。如何在冬季天然气供应紧张时期,考虑天然气的各类用途,实现天然气的合理分配,成为值得研究的重要课题。为此,引入粒子群多目标优化理论,充分考虑供给侧风电消纳与需求侧天然气负荷,综合设计了天然气供应收入最大化、供给侧风电消纳量最大化与天然气供应不确定性最小化3个目标函数,结合效用理论构建了考虑供应不确定性和调峰能力约束的天然气消费结构多目标优化分配模型,并以北京市城六区(东城区、西城区、朝阳区、海淀区、丰台区和石景山区)为例进行了模拟优化。研究结果表明:①天然气定价宜同时考虑社会效用和用户效用;②燃气机组调峰所带来的风电消纳效益受机组基本负荷利用小时数、燃气发电用气量以及供热期等因素的影响,从而验证了天然气消费结构的优化效果;③上述城六区应在原有天然气消费结构的基础上,小幅度增加发电、供热用气比例,保持商业及其他用气消费量稳定,大幅度缩减工业及天然气汽车用气量,以尽量满足居民用气量增加的需求。结论认为:北京市城六区优化后的天然气消费结构在满足各方天然气消费需求的同时,增加了总收入,提升了燃气机组调峰消纳风电的能力,证明该多目标优化分配模型能够为区域天然气消费结构优化调整提供理论和技术支撑。 展开更多
关键词 冬季 天然气消费结构 多目标优化分配 效用理论 粒子群算法 燃气机组调峰 风电消纳 北京市城六区
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青岛市冬季降尘中重金属的形态分析及其环境风险评估
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作者 伊丹 王艳 +2 位作者 刘汝海 徐红霞 张燕燕 《环境化学》 CAS CSCD 北大核心 2019年第9期1990-1997,共8页
在2017年冬季采集青岛市交通区、居民区、高教区和工业区等功能区的降尘样品,研究了金属元素(Al、Fe、Cd、Cr、Cu、Pb、Zn)的赋存形态和环境风险.结果表明,Cd、Cr、Cu、Pb、Zn的平均含量为0.5、56.4、231.2、143.5、394.1 mg·kg-1... 在2017年冬季采集青岛市交通区、居民区、高教区和工业区等功能区的降尘样品,研究了金属元素(Al、Fe、Cd、Cr、Cu、Pb、Zn)的赋存形态和环境风险.结果表明,Cd、Cr、Cu、Pb、Zn的平均含量为0.5、56.4、231.2、143.5、394.1 mg·kg-1,均超出了青岛土壤背景值,Cu的含量是背景值的12.8倍.Cd的可交换态(24.5%)和碳酸盐结合态(19%)所占比例较高,Pb、Zn的铁锰氧化态含量高,分别为23.7%、44.6%;Cu以有机态(70.2%)为主,Al、Fe、Cr、Pb金属主要赋存于残渣态中(46%—83%).功能区中的Cd、Pb、Zn的交换态和碳酸盐结合态以交通区和居民区比重较大,且与总量呈极显著相关(P<0.01);Cu、Cr的可交换态在居民区和交通区含量较高,两种金属的碳酸盐结合态分别在工业区和高教区含量较高,Cu的可交换态与总量呈正相关(P<0.05).风险评价编码法(RAC)表明降尘对环境构成的风险排序为Cd>Zn>Pb>Cu>Cr,Cd在各功能区处于高风险,Pb和Zn属于中等风险,Cr属于低风险.Cu在工业区处于中等风险,在其他3个功能区处于低风险. 展开更多
关键词 大气降尘 重金属 形态 风险评价 青岛市 冬季
太原市改造型养老院冬季室内热环境状况调查研究
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作者 刘雪麒 岳鹏 《暖通空调》 2019年第7期120-127,共8页
对太原市2个改造型养老院的冬季室内热环境参数进行了现场测试,对3个改造型养老院的老年人热舒适进行了主观问卷调查,采用相关性分析和回归分析的方法对数据进行了统计。结果显示:冬季老年人90%可接受热舒适温度范围为21.5~23.4℃,热中... 对太原市2个改造型养老院的冬季室内热环境参数进行了现场测试,对3个改造型养老院的老年人热舒适进行了主观问卷调查,采用相关性分析和回归分析的方法对数据进行了统计。结果显示:冬季老年人90%可接受热舒适温度范围为21.5~23.4℃,热中性温度为22.4℃,热期望温度为23.8℃;养老院冬季室内存在空气干燥、活动室过冷、老年人生活房间部分时段温度过高等问题。针对存在的问题,提出了相应的室内热环境改善措施。 展开更多
关键词 改造型养老院 冬季 室内热环境 热舒适 改善措施
Bacterial Community Structure of Sediment in Upstream Ecological Wetland of Guanting Reservoir under the Action of Different Plants in Winter 预览
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作者 Yan Donghua Jiang Tiantian +4 位作者 Li Hongbo Zhai Xuezheng Wang Mengyao Wang Jianghua Zhao Jianguo 《气象与环境研究:英文版》 CAS 2019年第1期46-48,51共4页
In order to study the effect of reed and cattail on the bacterial community structure of surface sediments of wetland in winter, high-throughput sequencing technology was used to analyze the bacterial composition. The... In order to study the effect of reed and cattail on the bacterial community structure of surface sediments of wetland in winter, high-throughput sequencing technology was used to analyze the bacterial composition. The results showed that 134 228 high-quality gene sequences were obtained by high-throughput sequencing in sediments of natural wetland in winter, and there were 13 866 OTUs, in which the number of OUT in sediments of reed wetland and cattail wetland was 6 677 and 7 189 respectively. The richness and diversity of bacterial communities in sediments of cattail wetland in winter were higher than those in sediments of reed wetland. Relative abundance of Proteobacteria in sediments of reed wetland and cattail wetland was 0.54 and 0.52, respectively. The dominant classes of bacteria were Betaproteobacteria, Deltaproteobacteria, Gammaproteobacteria and Epsilonproteobacteria, which belonged to gram-negative bacteria, indicating that the rhizosphere of wetland was easier to enrich gram-negative bacteria. Under the genus level, the dominant bacteria in the sediments were not obvious. 展开更多
关键词 HIGH-THROUGHPUT SEQUENCING Bacterial community SEDIMENT WINTER UPSTREAM ecological WETLAND of Guanting Reservoir
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黑龙江穆棱东北红豆杉自然保护区马鹿与狍冬季食性组成的比较 预览
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作者 朱明月 杨淼 +1 位作者 张玮琪 张明海 《东北林业大学学报》 CAS CSCD 北大核心 2019年第5期100-104,共5页
于2014-2015年冬季(1-3月份),通过野外调查及粪便样本采集,应用粪便显微组织学分析技术对黑龙江穆棱东北红豆杉国家级自然保护区的东北马鹿(Cervus elaphus xanthopygus)与狍(Capreolus pygargus)深冬时期的食性组成进行了比较研究。分... 于2014-2015年冬季(1-3月份),通过野外调查及粪便样本采集,应用粪便显微组织学分析技术对黑龙江穆棱东北红豆杉国家级自然保护区的东北马鹿(Cervus elaphus xanthopygus)与狍(Capreolus pygargus)深冬时期的食性组成进行了比较研究。分别跟踪东北马鹿和狍的足迹链,收集了43份东北马鹿粪便和40份狍粪便,共83份粪便样本,组成独立样本进行食性分析。结果表明:保护区内东北马鹿主要取食15种植物,青楷槭(Acer tegmentosum)和东北红豆杉(Taxus cuspidata)是主要食物,分别占21%、13%。马鹿取食阔叶植物(77%),针叶植物(13%),其余为蕨类植物和非禾本科草本植物。狍取食14种植物,主要食物为青楷槭和青杨(Populus cathayana),分别占22%、12%,未发现取食东北红豆杉,食性中阔叶植物占88%,蕨类植物和非禾本科草本植物占12%。保护区内同域分布的马鹿与狍取食植物种类相似,但食性比例不同。 展开更多
关键词 马鹿 东北地区 冬季 食性组成
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南京市仙林大学城冬季鸟类多样性初步调查——以文澜路3所高校为例 预览
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作者 郭少荣 陈凡 李一琳 《江苏林业科技》 2019年第2期25-31,共7页
物种多样性已成为评估一个地区生态环境质量优劣的主要标准。2017年11月—2018年1月,采用样线法对南京森林警察学院、南京师范大学、南京财经大学3所高校的仙林校区开展了鸟类资源调查。共记录鸟类20种,其中南京森林警察学院仙林校区鸟... 物种多样性已成为评估一个地区生态环境质量优劣的主要标准。2017年11月—2018年1月,采用样线法对南京森林警察学院、南京师范大学、南京财经大学3所高校的仙林校区开展了鸟类资源调查。共记录鸟类20种,其中南京森林警察学院仙林校区鸟类12种,隶属3目10科,其中留鸟11种,鸟类区系以古北界为主;南京师范大学仙林校区鸟类17种,隶属5目13科,留鸟14种,以广布种为主;南京财经大学仙林校区鸟类16种,隶属4目11科,留鸟13种,以广布种为主。3所校区鸟类组成兼具古北界和东洋界成分,以古北种占优势,广布种比例也较高。由SPSS分析结果知,南京师范大学和南京财经大学校区的鸟类物种多样性指数在乔木林、灌丛、草丛、水域和建筑区均高于南京森林警察学院校区。对比鸟类均匀性指数,南京师范大学在乔木林、水域和建筑区最高,南京森林警察学院则在灌丛和草丛环境最高。 展开更多
关键词 校园鸟类调查 冬季 物种多样性 鸟类区系 南京
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Recent Progress in Studies of the Variabilities and Mechanisms of the East Asian Monsoon in a Changing Climate 预览
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作者 Wen CHEN Lin WANG +4 位作者 Juan FENG Zhiping WEN Tiaojiao MA Xiuqun YANG Chenghai WANG 《大气科学进展:英文版》 SCIE CAS CSCD 2019年第9期887-901,共15页
Located in a monsoon domain,East Asia suffers devastating natural hazards induced by anomalous monsoon behaviors.East Asian monsoon(EAM)research has traditionally been a high priority for the Chinese climate community... Located in a monsoon domain,East Asia suffers devastating natural hazards induced by anomalous monsoon behaviors.East Asian monsoon(EAM)research has traditionally been a high priority for the Chinese climate community and is particularly challenging in a changing climate where the global mean temperature has been rising.Recent advances in studies of the variabilities and mechanisms of the EAM are reviewed in this paper,focusing on the interannual to interdecadal time scales.Some new results have been achieved in understanding the behaviors of the EAM,such as the evolution of the East Asian summer monsoon(EASM),including both its onset and withdrawal over the South China Sea,the changes in the northern boundary activity of the EASM,or the transitional climate zone in East Asia,and the cycle of the EASM and the East Asian winter monsoon and their linkages.In addition,understanding of the mechanism of the EAM variability has improved in several aspects,including the impacts of different types of ENSO on the EAM,the impacts from the Indian Ocean and Atlantic Ocean,and the roles of mid-to high-latitude processes.Finally,some scientific issues regarding our understanding of the EAM are proposed for future investigation. 展开更多
关键词 EAST ASIAN summer MONSOON EAST ASIAN winter MONSOON CHANGING CLIMATE MONSOON onset and withdrawal transitional CLIMATE zone different types of ENSO
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外面好冷呀!
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作者 Ruth Devlin VITALIA CHANG 《空中英语教室:初级版.大家说英语》 2019年第1期8-10,50共4页
冬季在许多地方都意味着寒冷。冬季的风暴可能会带来大雪。有时候,强风会把雪吹得漫天飞舞,使人们难以顺利开车或行走。在恶劣的天气下,学校可能会关闭,让学生待在家里。在冬季,温度会降低,而且经常会降到冰点以下。在有些地方,温度会... 冬季在许多地方都意味着寒冷。冬季的风暴可能会带来大雪。有时候,强风会把雪吹得漫天飞舞,使人们难以顺利开车或行走。在恶劣的天气下,学校可能会关闭,让学生待在家里。在冬季,温度会降低,而且经常会降到冰点以下。在有些地方,温度会降到华氏零度以下。一般人都不会待在户外的寒冷天气中,而是会待在室内保暖! 展开更多
关键词 冬季 寒冷 天气 温度 大雪 风暴 强风
夏季和冬季大气PM2.5水溶性颗粒物与总颗粒物对BEAS-2B细胞活性与炎症的影响
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作者 李美珍 刘宇飞 +8 位作者 曾晖娴 刁琴琴 张荣 邵月婷 张晗 丘妙韵 祝嘉璐 易艳妮 蒋义国 《环境与健康杂志》 CAS 北大核心 2019年第2期95-98,共4页
目的探讨夏季与冬季的大气颗粒物PM2.5水溶性成分与总颗粒物对BEAS-2B细胞的细胞活性与炎症的影响。方法将夏季和冬季采集的PM2.5分别提取水溶性成分与总颗粒物,得到4种PM2.5组分,使用CCK-8法检测25、50、100、200、400μg/ml PM2.5暴... 目的探讨夏季与冬季的大气颗粒物PM2.5水溶性成分与总颗粒物对BEAS-2B细胞的细胞活性与炎症的影响。方法将夏季和冬季采集的PM2.5分别提取水溶性成分与总颗粒物,得到4种PM2.5组分,使用CCK-8法检测25、50、100、200、400μg/ml PM2.5暴露细胞后的细胞活性;以100μg/ml PM2.5处理细胞12、24、48 h后提取RNA,用qRT-PCR技术检测IL-1α、IL-1β、IL-6、IL-8炎症因子与炎症小体NLRP3及caspase-1、IL-18的水平。结果夏季和冬季PM2.5的水溶性成分与总颗粒物分别处理细胞12 h后,部分剂量组细胞活性升高,随着PM2.5暴露时间的增加,细胞活性逐渐得到抑制,差异具有统计学意义(P<0.05)。100μg/ml的PM2.5处理细胞后,IL-1α和IL-1β表达水平高于IL-6和IL-8;炎症小体NLRP3、caspase-1和IL-18在100μg/ml的PM2.5处理24、48 h后也呈现升高趋势,差异具有统计学意义(P<0.05)。结论夏季和冬季PM2.5水溶性成分与总颗粒物可以抑制细胞活性,并且促使细胞炎症发生,冬季总颗粒物对细胞活性与炎症的影响更明显。 展开更多
关键词 夏季 冬季 PM2.5 BEAS-2B细胞 炎症 细胞活性 IL-1α IL-1β IL-6 IL-8 NLRP3 caspase-1 IL-18
心肌梗死超急性期心电图符合de Winter ST-T改变一例 预览
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作者 李玲玲 唐士敏 《实用心电学杂志》 2019年第2期149-150,共2页
心电图能快速、简便地诊断急性心肌梗死,在急性心肌梗死早期心电图就可以发生改变,此时心肌酶学可能还尚未升高。本文报道超急性期心肌梗死心电图表现为de-winter改变一例,此种心电图改变出现于前降支完全或次全闭塞的早期,在临床上比... 心电图能快速、简便地诊断急性心肌梗死,在急性心肌梗死早期心电图就可以发生改变,此时心肌酶学可能还尚未升高。本文报道超急性期心肌梗死心电图表现为de-winter改变一例,此种心电图改变出现于前降支完全或次全闭塞的早期,在临床上比较少见。 展开更多
关键词 DE WINTER 心电图 超急性期心肌梗死 非ST段抬高型心肌梗死
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Impact of Surface Potential Vorticity Density Forcing over the Tibetan Plateau on the South China Extreme Precipitation in January 2008. Part Ⅰ:Data Analysis
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作者 Tingting MA Guoxiong WU +2 位作者 Yimin LIU Zhihong JIANG Jiahui YU 《气象学报:英文版》 SCIE CSCD 2019年第3期400-415,共16页
The external source/sink of potential vorticity (PV) is the original driving force for the atmospheric circulation. The relationship between surface PV generation and surface PV density forcing is discussed in detail ... The external source/sink of potential vorticity (PV) is the original driving force for the atmospheric circulation. The relationship between surface PV generation and surface PV density forcing is discussed in detail in this paper. Moreover, a case study of the extreme winter freezing rain/snow storm over South China in January 2008 is performed, and the surface PV density forcing over the eastern flank of the Tibetan Plateau (TP) has been found to significantly affect the precipitation over South China in this case. The TP generated PV propagated eastward in the middle troposphere. The associated zonal advection of positive absolute vorticity resulted in the increasing of cyclo-nic relative vorticity in the downstream region of the TP. Ascending air and convergence in the lower troposphere developed, which gave rise to the development of the southerly wind. This favored the increasing of negative meridio-nal absolute vorticity advection in the lower troposphere, which provided a large-scale circulation background conducive to ascending motion such that the absolute vorticity advection increased with height. Consequently, the ascending air further strengthened the southerly wind and the vertical gradient of absolute vorticity advection between the lower and middle troposphere in turn. Under such a situation, the enhanced ascending, together with the moist air transported by the southerly wind, formed the extreme winter precipitation in January 2008 over South China. 展开更多
关键词 potential VORTICITY DENSITY (PVD) ABSOLUTE VORTICITY advection TIBETAN Plateau winter precipitation
果类蔬菜冬季集约化嫁接育苗关键技术
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作者 崔强 乜兰春 +2 位作者 贾明飞 张双双 王若男 《北方园艺》 CAS 北大核心 2019年第8期182-185,共4页
针对冬季低温寡照天气特点,介绍了果类蔬菜冬季集约化育苗关键技术,主要包括育苗设施装备、穴盘和基质选用,砧木和接穗品种选择、种子处理、播种、苗期在正常天气下以及连阴天、雨雪天、雾霾天气下的环境调控措施、幼苗水肥管理、嫁接... 针对冬季低温寡照天气特点,介绍了果类蔬菜冬季集约化育苗关键技术,主要包括育苗设施装备、穴盘和基质选用,砧木和接穗品种选择、种子处理、播种、苗期在正常天气下以及连阴天、雨雪天、雾霾天气下的环境调控措施、幼苗水肥管理、嫁接技术、主要病虫害的防治等,以期为育苗场在冬季培育优质健壮商品苗提供技术参考。 展开更多
关键词 冬季 果类蔬菜 集约化 嫁接育苗
Photos:An Ancient Ceremony To Celebrate The End Of Winter
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《英语文摘》 2019年第4期2-2,65共2页
Artists prepare to perform during Maslenitsa holiday celebrations in front of the Historical Museum in Manezhnaya Square, Moscow, near the Kremlin Wall, on March 9, 2019.(Alexander Zemlianichenko/AP)Maslenitsa is an a... Artists prepare to perform during Maslenitsa holiday celebrations in front of the Historical Museum in Manezhnaya Square, Moscow, near the Kremlin Wall, on March 9, 2019.(Alexander Zemlianichenko/AP)Maslenitsa is an ancient ceremony-a farewell to winter celebrated since pagan times in the Slavic regions of Russia, Belarus, Ukraine, and other countries. Maslenitsa,or Pancake Week, is both a folk and religious holiday tied to Shrovetide. 展开更多
关键词 CEREMONY WINTER HOLIDAY
Numerical Simulation of Bohai Oil Spill in the Winter Sea Ice Period 预览
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作者 WANG Kun DU Jing +4 位作者 LIU Ming WU Jin-hao JIANG Heng-zhi JIN Sheng SONG Lun 《中国海洋工程:英文版》 SCIE EI CSCD 2019年第2期185-197,共13页
The Bohai Sea is a seasonal icy sea area that has the lowest latitude of any sea experiencing icing in the northern hemisphere, and simulation studies on oil spills during its sea ice period are the key to analyzing w... The Bohai Sea is a seasonal icy sea area that has the lowest latitude of any sea experiencing icing in the northern hemisphere, and simulation studies on oil spills during its sea ice period are the key to analyzing winter oil spill accidents. This study applied the three-dimensional free surface to establish a high-resolution hydrodynamic model and simulate tidal distributions in the Bohai Sea. Then, the oil spill model of the open sea area and thermodynamic model were combined to establish a numerical model for the Bohai oil spill during the winter sea ice period. The hydrodynamic model and sea ice growth and melting model were verified, and the parameters were adjusted based on the measured values, which indicate that the numerical model established in this paper is of high accuracy, stability and ubiquity. Finally, after checking the calculations repeatedly, the diffusion coefficient for the Bohai Sea was determined to be 1.0×10^–7 m^2/s. It is better that the comprehensive weathering attenuation coefficient is lower than that of a non-winter oil spill, with 1.3×10^–7 m^2/s being the most appropriate coefficient. This study can provide the reliable technical support for the operational safety and reduction in losses caused by winter oil spill accidents for the petroleum industry. 展开更多
关键词 hydrodynamic MODEL SEA ICE growth and melt MODEL oil SPILL WINTER ICE PERIOD Bohai SEA
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WARM HEARTS ON FROZEN HOUHAI 预览
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作者 Si Thu Tun 《中国东盟报道》 2019年第2期78-79,共2页
Whether you want to practice your Flying V or polish your toe pick, Beijing's ice-skating rinks are the perfect surface for some winter fun.
关键词 BEIJING SURFACE WINTER
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石墨烯电热膜在冬季灌浆施工中的应用 预览
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作者 张娟娟 张伟民 《低温建筑技术》 2019年第8期133-134,141共3页
装配式建筑项目的施工受环境条件影响较大,其中北方地区面临主要问题就是冬季灌浆施工的低温问题。文中研究了用石墨烯电热膜为装配式建筑施工中灌浆料辅助加热的方法,分析了其操作性和可行性。结果表明,在冬季施工期,用石墨烯电热膜辅... 装配式建筑项目的施工受环境条件影响较大,其中北方地区面临主要问题就是冬季灌浆施工的低温问题。文中研究了用石墨烯电热膜为装配式建筑施工中灌浆料辅助加热的方法,分析了其操作性和可行性。结果表明,在冬季施工期,用石墨烯电热膜辅助加热,完全可以满足冬季施工要求,而且操作简便,可以在山东地区推广,其它地区可以借鉴此方法。 展开更多
关键词 石墨烯 电热膜 冬季 灌浆施工
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桂林地区福寿螺冬季繁殖力研究 预览
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作者 梁碧霞 黄锦龙 +1 位作者 韩丽霞 武正军 《广西师范大学学报:自然科学版》 CAS 北大核心 2019年第3期166-173,共8页
为了解冬季福寿螺Pomacea canaliculata繁殖力大小及其影响因素,于2017年12月中旬采集广西桂林地区福寿螺卵块,置于室温下进行孵化实验,记录孵化期间的气温以及孵化率,测量卵块长、宽、质量、卵粒总数和卵粒直径,并进行相关性分析。结... 为了解冬季福寿螺Pomacea canaliculata繁殖力大小及其影响因素,于2017年12月中旬采集广西桂林地区福寿螺卵块,置于室温下进行孵化实验,记录孵化期间的气温以及孵化率,测量卵块长、宽、质量、卵粒总数和卵粒直径,并进行相关性分析。结果表明:冬季福寿螺单块卵粒数为48~608粒,均值(mean±SD)为214.14±10.45粒;卵粒直径为2.31~3.32mm,均值(mean±SD)为2.69±0.018mm;孵化率为0~93.94%,均值(mean±SD)为29.21%±3.12%。其中冬季(12月—次年2月)孵化的卵粒占所有孵化卵粒的82.18%,春季(3月)孵化的卵粒仅占17.82%,表明福寿螺冬季产的卵主要采取冬季孵化策略。福寿螺孵化率与卵粒总数(r=0.365,P<0.001)呈显著正相关,与卵粒直径(r=-0.248,P=0.013)呈显著负相关,卵粒数多少是孵化率高低的关键。冬季孵化量与气温相关(r=0.607,P=0.002),春季孵化量随时间的延长而减少。 展开更多
关键词 冬季 福寿螺 繁殖参数 繁殖策略
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Effects of tridimensional uniform sowing on water consumption, nitrogen use, and yield in winter wheat 预览
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作者 Zhiqiang Tao Shaokang Ma +5 位作者 Xuhong Chang Demei Wang Yanjie Wang Yushuang Yang Guangcai Zhao Jiancang Yang 《作物学报:英文版》 CAS CSCD 2019年第4期480-493,共14页
Wheat is a staple crop worldwide, but yields may diminish as climate change causes increasingly unpredictable patterns of precipitation and soil nutrient availability. Farmers are thus challenged to maximize planting ... Wheat is a staple crop worldwide, but yields may diminish as climate change causes increasingly unpredictable patterns of precipitation and soil nutrient availability. Farmers are thus challenged to maximize planting efficiency to increase yield, while also improving their resource use efficiency. In this study the effectiveness of tridimensional uniform sowing was tested across a range of planting densities for winter wheat crops on the North China Plain. Tridimensional uniform sowing was tested against conventional drilling at three planting densities (180 × 104, 270 × 104, and 360 × 104 plants ha 1) and assessed for water consumption, biomass, nitrogen uptake and allocation, and aspects of yield. The tridimensional uniform sowing treatment outperformed the conventional drilling treatment in most metrics and at most planting densities, while performing markedly better at higher planting densities. Water consumption decreased and nitrogen efficiency increased. Tiller number and percentage of productive tillers, leaf area index, dry weight, and yield increased without a significant decline in grain protein. Nitrogen allocation was more efficient under tridimensional uniform sowing than with conventional drilling, and also varied according to annual precipitation and planting density. Both yield and grain protein contents were significantly correlated with the amount of pre-anthesis accumu- lated nitrogen translocated from vegetative organs to kernels after anthesis. Overall, a density of 270 × 104 plants ha 1 provided the highest water use efficiency and grain yield. Tridimensional uniform sowing will benefit farmers by forming stronger overall crops, promoting the coordinated improvement of yield, nitrogen uptake and efficiency, and increasing grain protein content at higher planting densities. 展开更多
关键词 Winter wheat SOWING pattern NITROGEN absorption and utilization YIELD GRAIN protein content
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三门峡天鹅湖湿地公园大天鹅越冬初期食性分析 预览
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作者 于海龙 牛童 +5 位作者 陈光 吴渊 茹文东 李云峰 高如意 洪剑明 《野生动物学报》 北大核心 2019年第3期652-663,共12页
采用粪便显微分析法,2014年11—12月、2015年11月对大天鹅粪便中的植物残片与27种植物进行对比、分类、统计,得到结果:大天鹅越冬初期食物比例中,小麦最多,占40.44%;玉米粒占17.23%,芦苇3.03%、菵草2.02%、苍耳1.41%、牵牛1.21%、酸模叶... 采用粪便显微分析法,2014年11—12月、2015年11月对大天鹅粪便中的植物残片与27种植物进行对比、分类、统计,得到结果:大天鹅越冬初期食物比例中,小麦最多,占40.44%;玉米粒占17.23%,芦苇3.03%、菵草2.02%、苍耳1.41%、牵牛1.21%、酸模叶蓼1.04%、睡莲0.95%、多花水苋0.66%、苘麻0.61%、早熟禾0.58%、红鳞扁莎和齿果酸模均为0.52%。大天鹅取食具有广泛性,且对小麦有取食偏好。大天鹅取食的植物中占比最大的是禾本科植物,占63.57%,其次是蓼科1.56%,菊科1.41%,旋花科1.21%。 展开更多
关键词 三门峡 大天鹅 越冬 食性
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