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设施蔬菜大棚土壤氮磷钾养分富积降低土壤钙素的有效性

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植物营养与肥料学报 2018年第4期24卷 1019-1026页

作者：韩巍赵金月李豆豆郭磊磊窦莉洋刘静李嵩依艳丽沈阳农业大学土地与环境学院辽宁沈阳110866

【目的】随着种植年限的增加,设施农业缺钙性生理病害发生率迅速上升。设施土壤中氮磷钾元素的富积与土壤中钙素的形态及有效性有密切关系,进而影响植物对钙素的吸收。因此,本研究调查比较了不同种植年限设施菜地土壤钙素有效性的变化,... 详细信息

【目的】随着种植年限的增加,设施农业缺钙性生理病害发生率迅速上升。设施土壤中氮磷钾元素的富积与土壤中钙素的形态及有效性有密切关系,进而影响植物对钙素的吸收。因此,本研究调查比较了不同种植年限设施菜地土壤钙素有效性的变化,及与N、P、K含量的关系,为提高土壤钙素有效性和减少缺钙性生理病害提供理论依据。【方法】在辽宁省海城市选取了38个设施蔬菜大棚,种植年限在3~30年不等,土壤均为棕壤,按照每三年为一个时间段,将大棚分为9组。采集了棚内0—20 cm的耕层土壤样品,同时采集棚外露地0—20 cm土壤样品作为对照。分析了有机质、氮、磷、钾养分含量,分别测定了土壤水溶性钙、交换性钙、酸溶性钙、非酸溶性钙含量,利用回归方法计算了氮磷钾含量与四种形态钙含量之间的关系。【结果】随着种植年限延长,设施土壤有机质、氮、磷、钾、总钙、酸溶性钙和非酸溶性钙含量逐年增加,水溶性钙和交换性钙分别在种植达到9~11年和12~14年时达到最大值104.1和611.9 mg/kg,之后呈下降趋势。总钙增加量的94.3%~96.4%属无效态的非酸溶性钙。土壤中氮、钾含量的提高促进了交换性钙的解吸,铵态氮和速效钾含量与交换性钙呈显著负相关(r=–0.5451,P<0.01;r=–0.4809,P<0.01,n=38)。土壤中磷含量的提高促进了难溶性磷酸钙盐的形成,磷酸高钙盐与无效性的非酸溶性钙呈极显著正相关(r=0.5884,P<0.01,n=38)。种植30年的设施土壤有效态钙含量与有效氮、磷、钾的比例比露地土壤下降了近70%。【结论】随着设施蔬菜种植年限的增加,土壤中的氮、磷、钾养分含量不断增加。氮和钾含量的增加促进了交换性钙的解吸,磷的增加促进了水溶态和交换态钙向无效的非酸溶性钙的转化。因此,土壤中氮磷钾的富积加剧了蔬菜土壤有效性钙的缺乏。

关键词：种植年限设施土壤土壤钙素形态养分平衡

N型Yb_(x)Co_(4)Sb_(12)热电材料及涂层的制备与性能研究

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稀有金属材料与工程 2021年第11期50卷 3971-3978页

作者：李斗徐长江李旭光李双明钟宏西北工业大学凝固技术国家重点实验室陕西西安710072

采用熔融-退火-放电等离子烧结工艺制备了Yb_(x)Co_(4)Sb_(12)(x=0.27,0.28,0.29,原子比)合金块体样品。XRD、SEM、EDS分析表明,成功合成了Yb掺杂的单相CoSb_(3)热电材料。当Yb含量从0.27上升至0.29,材料的功率因子随温度的升高呈现先... 详细信息

采用熔融-退火-放电等离子烧结工艺制备了Yb_(x)Co_(4)Sb_(12)(x=0.27,0.28,0.29,原子比)合金块体样品。XRD、SEM、EDS分析表明,成功合成了Yb掺杂的单相CoSb_(3)热电材料。当Yb含量从0.27上升至0.29,材料的功率因子随温度的升高呈现先上升后下降趋势,热导率则先下降后上升。由于相对较高的功率因子1815μW·m^(-1)·K^(-2)以及较低的热导率2.23 W·m^(-1)·K^(-1),合金Yb_(0.29)Co_(4)Sb_(12)在773 K时获得较高的ZT值0.62。以磁控溅射法对N型热电元件Yb_(0.29)Co_(4)Sb_(12)进行Al-Ni防护涂层溅射,SEM、EDS结果表明涂层与基底结合良好,经涂层防护后的Yb_(0.29)Co_(4)Sb_(12)元件热电性能稳定性较好。以钎料Ag40Cu60对热电材料Yb_(0.29)Co_(4)Sb_(12)与电极片Mo50Cu50的接头进行焊接,发现界面处结合良好,界面处Co、Sb、Yb、Mo等元素未发生严重扩散。

关键词： CoSb_(3) 热电材料 Al-Ni涂层热电性能

A prediction model for large vessel occlusion in suspected stroke patients based on available prehospital information

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Journal of Translational Neuroscience 2024年第3期9卷 26-35页

作者： Milan Jia Shuaili Xu dou li Sijie li Changhong Ren Wenbo Zhao Jing Lan Xunming Ji Department of Neurology Xuanwu HospitalCapital Medical UniversityBeijing 100053China Beijing Institute of Brain Disorders Laboratory of Brain DisordersMinistry of Science and TechnologyCollaborative Innovation Center for Brain DisordersCapital Medical UniversityBeijing 100069China China-America Institute of Neuroscience Xuanwu HospitalCapital Medical UniversityBeijing 100053China Department of Emergency Medicine Beijing Emergency Medical CenterBeijing 100031China Department of Emergency Xuanwu HospitalCapital Medical UniversityBeijing 100053China Beijing Key Laboratory of Hypoxic Conditioning Translational Medicine Xuanwu HospitalCapital Medical UniversityBeijing 100053China Department of Neurosurgery Xuanwu HospitalCapital Medical UniversityBeijing 100053China

Objective:Early and accurate identification of large vessel occlusion(LVO)acute ischemic stroke(AIS)patients is critically important for stroke *** scales with simple items can facilitate prehospital paramedics distinguishing LVO-AIS patients with high efficiency and help to avoid unnecessary and costly *** current study aims to develop a screening tool to predict AIS-LVO patients based on prehospital available ***:A total of 251 suspected stroke patients who were transported to the emergency department of our hospital via emergency medical services were consecutively enrolled from August,2020 to January,*** including demographic information,medical history,clinical manifestations,and vital signs were collected.A multivariate logistic regression model was developed based on statistically significant variables selected from univariate ***:Forty-two patients(16.7%)were diagnosed as LVO-AIS based on imaging validation at admission.A comprehensive model was developed with past medical history factors such as atrial fibrillation and coronary heart disease,vital signs such as systolic blood pressure,and prominent symptoms and signs such as gaze palsy,facial paralysis,and *** model showed better diagnostic performance in terms of area under the receiver operating characteristic curves(0.884,95%CI,0.830-0.939),which was higher than other common prehospital prediction scales such as the Face,Arm,Speech,Time test(FAST),the Field Assessment Stroke Triage for Emergency Destination(FAST-ED)scale,and the Gaze-Face-Arm-Speech-Time test(G-FAST).Calibration curve analysis,decision curve analysis,and clinical impact curve analysis further validated the reliability,net benefit,and potential clinical impact of the prediction model,***:We conducted a prediction model based on prehospital accessible factors including past history of atrial fibrillation and coronary heart disease,systolic blood pressure,and

关键词： acute ischemic stroke large vessel occlusion prediction model emergency medical service

The Study of Paleoearthquakes on the Weihe Fault Zone

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Earthquake Research in China 2008年第4期22卷 470-480页

作者： Shi Yaqin Feng Xijie Dai Wangqiang Ren Jun li Xiaoni dou Mali Earthquake Administration of Shaanxi Province Xi＇an 710068 China

It is indicated by historical records and the exploratory trench on the Weihe fault that the Yaodian-Zhangjiawan segment of the Weihe fault zone has experienced a historical earthquake and 3 paleoearthquake events in the past 9110a. The historical earthquake, namely, event Ⅳ, occurred between 1487 and 1568 AD. The date of paleoseismic event Ⅰ is （9110 ＋ 90） a, and the ages of events Ⅱ and Ⅲ are unknown. The coseismic vertical displacement of events Ⅰ, Ⅱ and Ⅲ is 0.5m, 0.5m and 0.2m, respectively. The exploratory trench also indicates that the Yaodian-Zhangjiawan segment of the Weihe fault was active in the Holocene.

关键词： Weihe fault zone Paleoearthquake Coseismic displacement Exploratory trench Bilicun Village

“互联网+”环境下体育科技期刊发展现状与优化途径

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武汉体育学院学报 2017年第5期51卷 28-31页

作者：李伟窦志武汉体育学院期刊社湖北武汉430079 武汉体育学院图书馆湖北武汉430079

"互联网+"时代赋予了科技期刊发展新内涵,是对期刊传统出版发行模式的较量。用"互联网+"的发展思维来衡量当前体育科技期刊的发展现状,其在数字化建设层面、读者需求满足层面和出版发行效益层面存在不小的差距。新时期,体育科技期刊需... 详细信息

"互联网+"时代赋予了科技期刊发展新内涵,是对期刊传统出版发行模式的较量。用"互联网+"的发展思维来衡量当前体育科技期刊的发展现状,其在数字化建设层面、读者需求满足层面和出版发行效益层面存在不小的差距。新时期,体育科技期刊需充分结合学科优势,按照学术期刊的自身发展规律,把"互联网+"作为重要的发展方向,将发展理念、阅读需求、采编思维、品牌建设、社会和经济效益五个方面作为突破点,以此来对体育科技期刊的发展方式进行优化,努力构建"互联网+体育科技期刊"出版发行全新模式。

关键词：体育科技期刊互联网+ 发展方式优化出版模式创新

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融合项目属性和用户兴趣迁移的协同过滤算法

计算机仿真 2022年第5期39卷 304-308,469页

作者：李豆豆汪学明贵州大学计算机与科学技术学院贵州贵阳550000

协同过滤算法作为各种商业推荐技术最常使用的方法之一。然而,由于数据的稀疏性和用户的评分存在单一的相似性,低精度相似度度量降低了推荐系统的性能。针对上述问题,提出了一种协同过滤改进方法。方法基于项目的分类属性,以用户的兴趣... 详细信息

协同过滤算法作为各种商业推荐技术最常使用的方法之一。然而,由于数据的稀疏性和用户的评分存在单一的相似性,低精度相似度度量降低了推荐系统的性能。针对上述问题,提出了一种协同过滤改进方法。方法基于项目的分类属性,以用户的兴趣度量用户的相似度,量化用户的兴趣所发生的动态迁移,构建新的相似度量模型。Movielens测试结果表明,提出的算法缓解了数据稀疏性,优化了最近邻的选取,与传统算法相比有着更高的推荐精度。

关键词：协同过滤项目分类属性相似度度量数据稀疏性用户兴趣变化

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频分及时分寻呼网络的设计

电信科学 1998年第1期14卷 11-13页

作者：窦笠邮电部设计院

本文介绍了实现大范围寻呼覆盖的不同方法，网络设计从简单的大同播区网络到复杂的频分或时分网络。

关键词：寻呼网络频分时分无线数据通信

Protective effect of heme oxygenase-1 on lung injury induced by erythrocyte instillation in rats

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Chinese Medical Journal 2008年第17期121卷 1688-1692页

作者： PANG Qing-feng ZHOU Qiao-mei ZENG Si dou li-dong JI Yong ZENG Yin-ming Department of Pathophysiology Xuzhou Medical College Xuzhou Jiangsu 221002 China Jiangsu Province Institute of Anesthesiology Xuzhou Medical College Xuzhou Jiangsu 221004 China

Background Intratracheal instillation of blood induces self-repaired acute lung injury. However, the mechanism of repair has been unclear. Heme-oxygenase （HO）-1, which catalyzes heme breakdown, acts as an inducible defense against oxidative stress and plays an important role in inflammation. The objective of this study was to test the role of HO-1 in lung injury caused by intratracheal instillation of red cells. Methods Forty healthy, male Sprague-Dawley rats were randomly divided into five groups： normal group, saline group, erythrocyte group, erythrocyte＋zinc-protoporphyrin （ZnPP, HO-1 inhibitor） group and saline＋ZnPP group. At 2 days after intratracheal instillation of red cells, lung tissues and lavage samples were isolated for biochemical determinations and histological measurements. Results Histological analysis revealed that administration of ZnPP worsened the acute lung injury induced by instilled erythrocytes. HO-1 was over-expressed in the erythrocyte group and in the erythrocyte ＋ ZnPP group. Compared with the erythrocyte ＋ ZnPP group, the levels of total protein, lactate dehydrogenase and tumor necrosis factor-a in the lavage were lower （P 〈0.01）, while the level of interleukin-10 was higher in the erythrocyte group （P 〈0.01）. Conclusion HO-1 protects against erythrocyte-induced inflammatory injury in lung.

关键词： erythrocyte acute lung injury heine oxygenase-1

有氧运动对高血压大鼠血压和血浆PGI2／TXA2系统的影响

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西安体育学院学报 2008年第2期25卷 76-78,84页

作者：窦丽张钧南京林业大学体育部南京210037 扬州大学运动人体科学研究所江苏扬州225109

为了探讨有氧运动对自发性高血压大鼠(SHR)血压和血浆前列环素/血栓烷A2(PGI2/TXA2)系统的影响,对大鼠进行为期10周,每周5次,每次60 min的游泳运动训练,测定体重、血压、血浆6-Keto-PGF1α和TXB2含量。结果表明,有氧运动能明显抑制SHR... 详细信息

为了探讨有氧运动对自发性高血压大鼠(SHR)血压和血浆前列环素/血栓烷A2(PGI2/TXA2)系统的影响,对大鼠进行为期10周,每周5次,每次60 min的游泳运动训练,测定体重、血压、血浆6-Keto-PGF1α和TXB2含量。结果表明,有氧运动能明显抑制SHR大鼠体重的增长幅度,降低大鼠血压水平和血浆TXB2含量,能明显提高血浆6-Keto-PGF1α含量,显著改善PGI2/TXA2系统平衡,防治高血压及其血栓形成。

关键词：有氧运动自发性高血压大鼠 6-酮-前列腺素F1α 血栓素B2 PGI2/TXA2系统