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2024年全球数字化营销风向 被引量:1
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作者 《中国眼镜科技杂志》 2024年第4期78-79,共2页
在数字化时代的浪潮中,数据成为塑造市场趋势的关键驱动力。随着全球营销界的不断探索和发展,人工智能逐渐成为营销人员的得力助手,更导致了市场格局的快速演变。那么,2024年,全球数字化营销有哪些风向与趋势?
关键词 数字化营销 全球营销 人工智能 数字化时代 市场趋势 营销人员 驱动力 风向
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Estimation of the Carbon Sequestration Dynamics of Senegal’s Great Green Wall Based on Land Cover over the Past Three Decades
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作者 Bi Tra Olivier Gore Angora Aman +2 位作者 Yves K. Kouadio Ody-Marc Duclos Kazunao Sato 《Journal of Environmental Protection》 2023年第12期954-983,共30页
The severe drought observed in the Sahel during 1970s, 1980s and 1990s has deeply affected the population as well as the economies and the eco-systems of this climatic area. The GGW Initiative spearheaded by Africa Un... The severe drought observed in the Sahel during 1970s, 1980s and 1990s has deeply affected the population as well as the economies and the eco-systems of this climatic area. The GGW Initiative spearheaded by Africa Union in 2007 proposed to combat the land degradation and desertification by planting a wall of trees stretching from Dakar to Djibouti. A reforestation was then conducted in the Senegal’s GGW since 2006 as part as other areas in the Sahel. This paper aims to evaluate the carbon sequestration dynamics in the sites of the Senegal’s GGW over the last three decades. The method consists firstly of analyzing the evolution of land cover and land use dynamics based on ESA-CCI LC satellite data. There is an improvement of the surface areas of tree and shrub savanna of 11.40% (Tessekere), 8.25% (Syer) and 2.70% (Loughere-Thioly). The regreening of the different localities and a positive dynamic observed is explained by the return to normal rainfall and to reforestation actions, agroforestry practices, better management of natural resources undertaken. However, some non-reforested sites showed an opposite trend despite of the normal rainfall. Secondly, the results on land mapping are used as a proxy for the assessment of carbon stocks. The dynamic observed in vegetation cover since the beginning of the reforestation made it possible to sequester 5.8 million tons of carbon representing respectively 2.31% of African GGW. This gain in stored carbon is equivalent to 21.2 million tons of CO<sub>2</sub> captured in the atmosphere. Through this study, it appears that carbon storage becomes significant 8 to 10 years after the start of reforestation. An urbanization without respect for the environmental factors could be a danger for the climate (case of Ballou). 展开更多
关键词 Great Green Wall of Senegal Land Cover-Land Use (LCLU) Carbon Storage
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Patient Experience at Endoscopy Centers in Three West African Countries during the COVID-19 Pandemic
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作者 Alice Nanelin Guingané Euloge Houndonougbo +7 位作者 Jamila Abdouramane Soli Léonce Steve Zoungrana Sandrine Soudré Aboubacar Coulibaly Sosthène Somda Roger Sombié Appolinaire Sawadogo Alain Bougouma 《Open Journal of Gastroenterology》 CAS 2023年第4期161-169,共9页
Corona virus infection and the risk of contagiousness to medical personnel or patients during endoscopy necessitated further measures in the endoscopy rooms. The objective of this study was to assess the experience of... Corona virus infection and the risk of contagiousness to medical personnel or patients during endoscopy necessitated further measures in the endoscopy rooms. The objective of this study was to assess the experience of patients in endoscopy rooms during the COVID-19 epidemic in West Africa. Patients and Methods: This was a multicenter cross-sectional study that took place over a period of 3 months (June to August 2020) in endoscopy centers in Burkina Faso, Benin and Niger. An online questionnaire was sent to patients who had performed upper digestive endoscopies, in 8 digestive endoscopy centers including private, public and religious structures. Depending on the choice of patients, questionnaires were either sent electronically or completed in the endoscopy room with the help of field investigators. The choice of centers was random from the list of centers and descriptive analyses were carried out. Results: A total of 294 patients responded to the online questionnaire. There were 37 lower and 257 upper gastrointestinal endoscopies. The female sex represented 52.1%. The wait times for obtaining an endoscopy appointment were considered satisfactory by 281 patients 95.6%. In the endoscopy departments, 112 patients, or 38.1%, were questioned about the risk factors for contamination of SARS-CoV-2. Among the risk factors found, 6 patients (2.0%) would have traveled abroad in the 2 weeks preceding the examination, 4 patients 1.4% had already been in contact with a subject at risk. The most frequent symptoms were chest pain (80 cases;27.2%), flu-like syndrome (29 cases;9.9%), cough (40 cases;13.6%), fever (46 cases;15.6%). In contrast, ageusia (7 cases;2.4%) and anosmia (5 cases;1.7%) were only found in very few patients. Twenty-two patients (7.5%) felt highly exposed to COVID-19 during the endoscopy examination and 144 patients (48.9%) rated the examination as satisfactory. Conclusion: Gastrointestinal symptoms initially described as rare are being reported with increasing frequency in studies and may motivate the request for endoscopy examinations. However, the risk associated with infection with SARS-CoV-2 does not seem to have been sufficiently taken into account in endoscopy centers in the 3 countries. 展开更多
关键词 ENDOSCOPY COVID-19 Patients Exposure SYMPTOMS
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The effect of ensiled paulownia leaves in a high-forage diet on ruminal fermentation,methane production,fatty acid composition,and milk production performance of dairy cows
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作者 Haihao Huang Dorota Lechniak +7 位作者 Malgorzata Szumacher‑Strabel Amlan Kumar Patra Martyna Kozłowska Pawel Kolodziejski Min Gao Sylwester Ślusarczyk Daniel Petrič Adam Cieslak 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2023年第1期339-357,共19页
Background:The use of industrial by-products rich in bioactive compounds as animal feeds can reduce greenhouse gas production.Paulownia leaves silage(PLS)was supplemented to dairy cows'diet and evaluated in vitro(... Background:The use of industrial by-products rich in bioactive compounds as animal feeds can reduce greenhouse gas production.Paulownia leaves silage(PLS)was supplemented to dairy cows'diet and evaluated in vitro(Exp.1;Rusitec)and in vivo(Exp.2,cannulated lactating dairy cows and Exp.3,non-cannulated lactating dairy cows).The study investigated the PLS effect on ruminal fermentation,microbial populations,methane production and concentration,dry matter intake(DMI),and fatty acid(FA)proportions in ruminal fluid and milk.Results:Several variables of the ruminal fluid were changed in response to the inclusion of PLS.In Exp.1,the p H increased linearly and quadratically,whereas ammonia and total volatile fatty acid(VFA)concentrations increased linearly and cubically.A linear,quadratic,and cubical decrease in methane concentration was observed with increasing dose of the PLS.Exp.2 revealed an increase in ruminal p H and ammonia concentrations,but no changes in total VFA concentration.Inclusion of PLS increased ruminal propionate(at 3 h and 6 h after feeding),isovalerate,and valerate concentrations.Addition of PLS also affected several populations of the analyzed microorganisms.The abundances of protozoa and bacteria were increased,whereas the abundance of archaea were decreased by PLS.Methane production decreased by 11%and 14%in PLS-fed cows compared to the control in Exp.2 and 3,respectively.Exp.3 revealed a reduction in the milk protein and lactose yield in the PLS-fed cows,but no effect on DMI and energy corrected milk yield.Also,the PLS diet affected the ruminal biohydrogenation process with an increased proportions of C18:3 cis-9 cis-12 cis-15,conjugated linoleic acid,C18:1 trans-11 FA,polyunsaturated fatty acids(PUFA),and reduced n6/n3 ratio and saturated fatty acids(SFA)proportion in milk.The relative transcript abundances of the 5 of 6 analyzed genes regulating FA metabolism increased.Conclusions:The dietary PLS replacing the alfalfa silage at 60 g/kg diet can reduce the methane emission and improve milk quality with greater proportions of PUFA,including conjugated linoleic acid,and C18:1 trans-11 along with reduction of SFA. 展开更多
关键词 Dairy cow Fatty acid composition in milk Methane emission Paulownia leaves
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Inflammatory bowel disease among first generation immigrants in Israel:A nationwide epi-Israeli Inflammatory Bowel Disease Research Nucleus study
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作者 Mira Stulman Gili Focht +9 位作者 Yiska Loewenberg Weisband Shira Greenfeld Amir Ben Tov Natan Ledderman Eran Matz Ora Paltiel Shmuel Odes Iris Dotan Eric Ian Benchimol Dan Turner 《World Journal of Methodology》 2023年第5期475-483,共9页
BACKGROUND Israel has a high rate of Jewish immigration and a high prevalence of inflammatory bowel disease(IBD).AIM To compare IBD prevalence in first-generation immigrants vs Israel-born Jews.METHODS Patients with a... BACKGROUND Israel has a high rate of Jewish immigration and a high prevalence of inflammatory bowel disease(IBD).AIM To compare IBD prevalence in first-generation immigrants vs Israel-born Jews.METHODS Patients with a diagnosis of IBD as of June 2020 were included from the validated epi-IIRN(Israeli IBD Research Nucleus)cohort that includes 98%of the Israeli population.We stratified the immigration cohort by IBD risk according to country of origin,time period of immigration,and age group as of June 2020.RESULTS A total of 33544 patients were ascertained,of whom 18524(55%)had Crohn’s disease(CD)and 15020(45%)had ulcerative colitis(UC);28394(85%)were Israel-born and 5150(15%)were immigrants.UC was more prevalent in immigrants(2717;53%)than in non-immigrants(12303,43%,P<0.001),especially in the<1990 immigration period.After adjusting for age,longer duration in Israel was associated with a higher point prevalence rate in June 2020(high-risk origin:Immigration<1990:645.9/100000,≥1990:613.2/100000,P=0.043;intermediate/low-risk origin:<1990:540.5/100000,≥1990:192.0/100000,P<0.001).The prevalence was higher in patients immigrating from countries with high risk for IBD(561.4/100000)than those originating from intermediate-/low-risk countries(514.3/100000;P<0.001);non-immigrant prevalence was 528.9/100000.CONCLUSION Lending support to the environmental effect on IBD etiology,we found that among immigrants to Israel,the prevalence of IBD increased with longer time since immigration,and was related to the risk of IBD in the country of origin.The UC rate was higher than that of CD only in those immigrating in earlier time periods. 展开更多
关键词 EPIDEMIOLOGY Inflammatory bowel disease IMMIGRATION Environment
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祁连山区黑河上游多年冻土分布考察 被引量:30
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作者 王庆峰 张廷军 +6 位作者 吴吉春 彭小清 钟歆玥 牟翠翠 王康 吴青柏 程国栋 《冰川冻土》 CSCD 北大核心 2013年第1期19-29,共11页
高山多年冻土的分布及土壤季节冻融过程对地表水文过程、生态系统、碳循环及寒区工程建设等都有很大的影响.黑河上游地处祁连山中东部,属于高原亚寒带半干旱气候,研究黑河流域多年冻土分布对于系统理解该区域的生态-水文过程、气候与环... 高山多年冻土的分布及土壤季节冻融过程对地表水文过程、生态系统、碳循环及寒区工程建设等都有很大的影响.黑河上游地处祁连山中东部,属于高原亚寒带半干旱气候,研究黑河流域多年冻土分布对于系统理解该区域的生态-水文过程、气候与环境变化以及水资源评价、工程建设等非常重要.2011年6—8月对黑河干流源头西支开展了多年冻土调查,沿二尕公路(S204)在热水大坂垭口至石棉矿岔口之间区域,完成测温孔7眼,并布设测温管进行地温监测.根据勘察、钻探及测温资料,确定了黑河源头地区山地多年冻土下界为海拔3 650~3 700m之间.受高度地带性的控制,随着海拔的降低,活动层厚度由在海拔4 132m时的1.6m增加至在多年冻土下界处的约4.0m,多年冻土年平均地温也相应的由-1.7℃增加到0.0℃左右,而多年冻土厚度由100m以上减小到多年冻土下界处的0.0m.同时,坡度和坡向、岩性、含水(冰)量、地下水、河水等局地因素对多年冻土温度和厚度也有重要的作用. 展开更多
关键词 多年冻土下界 活动层 海拔 年平均地温 黑河流域
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祁连山区黑河上游俄博岭多年冻土区活动层碳储量研究 被引量:16
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作者 牟翠翠 张廷军 +3 位作者 曹斌 万旭东 彭小清 程国栋 《冰川冻土》 CSCD 北大核心 2013年第1期1-9,共9页
为了探索在全球气候变化背景下多年冻土区碳储量现状,通过野外实地勘探和室内实验,对黑河上游俄博岭多年冻土区地貌特征及不同海拔活动层内的碳储量进行考察和估算.结果表明:黑河上游俄博岭冰缘现象显著,土壤季节冻融过程活跃,且活动层... 为了探索在全球气候变化背景下多年冻土区碳储量现状,通过野外实地勘探和室内实验,对黑河上游俄博岭多年冻土区地貌特征及不同海拔活动层内的碳储量进行考察和估算.结果表明:黑河上游俄博岭冰缘现象显著,土壤季节冻融过程活跃,且活动层中碳储量丰富.在研究区约2.5×106 m2的范围内,活动层平均厚度约为1.1m,活动层土壤有机质平均含量约为72.1%,碳储量估算约为1.57Mt C.活动层不同深度处有机质含量呈现不同的变化规律.随着活动层深度增加,土壤有机质的含量逐渐降低,在多年冻土上限附近有机质含量较高.另外,活动层有机质含量随着海拔和土壤含水量的不同而变化,同时多年冻土区微地形和地质条件也对有机质含量具有重要的影响. 展开更多
关键词 活动层 气候变暖 有机质含量 碳储量估算
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欧亚大陆积雪分布及其类型划分 被引量:40
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作者 张廷军 钟歆玥 《冰川冻土》 CSCD 北大核心 2014年第3期481-490,共10页
利用1966-2012年欧亚大陆1 152个地面气象台站积雪深度资料,对欧亚大陆积雪深度、累计积雪天数和连续积雪天数的空间分布进行了分析,以连续积雪天数为标准对欧亚大陆季节性积雪类型进行了划分,并与应用累计积雪天数对积雪区类型的划分... 利用1966-2012年欧亚大陆1 152个地面气象台站积雪深度资料,对欧亚大陆积雪深度、累计积雪天数和连续积雪天数的空间分布进行了分析,以连续积雪天数为标准对欧亚大陆季节性积雪类型进行了划分,并与应用累计积雪天数对积雪区类型的划分进行了比较研究.结果表明:欧亚大陆积雪分布具有显著纬度地带性特征,积雪深度、累计积雪天数和连续积雪天数的大值分布区均位于俄罗斯平原的东北部、科拉半岛、西西伯利亚平原、中西伯利亚高原以及俄罗斯远东北部大部分区域.与累计积雪天数划分方法相比,利用连续积雪天数对欧亚大陆季节性积雪分区,在前苏联地区积雪类型分区差异并不显著,但蒙古和中国的稳定积雪区明显缩减,青藏高原无稳定积雪区,中国大部分地区为非周期性不稳定积雪区.两种积雪分区划分方法比较结果显示,连续积雪天数划分方法更能体现积雪累积的连续性和持久性,更符合对稳定积雪和不稳定积雪的划分标准. 展开更多
关键词 积雪深度 积雪天数 积雪类型 欧亚大陆
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我国冰冻圈及其变化的脆弱性与评估方法 被引量:14
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作者 杨建平 张廷军 《冰川冻土》 CSCD 北大核心 2010年第6期1084-1096,共13页
基于脆弱性研究文献,从脆弱性概念、评估内容、评估方法等方面系统总结了脆弱性评估研究的特点和趋势,开展脆弱性评估时应注意的系统、关注特征、灾害、尺度与时间等五个方面,剖析了区域尺度脆弱性评估涉及的一系列问题,介绍了脆弱性评... 基于脆弱性研究文献,从脆弱性概念、评估内容、评估方法等方面系统总结了脆弱性评估研究的特点和趋势,开展脆弱性评估时应注意的系统、关注特征、灾害、尺度与时间等五个方面,剖析了区域尺度脆弱性评估涉及的一系列问题,介绍了脆弱性评估方法及其优缺点和适用性.探讨了我国冰冻圈及其变化的脆弱性概念,分析了二者之间的关系,论述了我国冰冻圈及其变化的脆弱性评估内容、评估尺度和评估方法. 展开更多
关键词 脆弱性 冰冻圈的脆弱性 冰冻圈变化的脆弱性 脆弱性评估方法
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中国寒区水文学研究的新阶段——记我国杰出寒区水文学家叶柏生研究员的创新与贡献 被引量:7
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作者 丁永建 刘时银 +6 位作者 刘凤景 杨大庆 张廷军 赵林 沈永平 阳坤 张世强 《冰川冻土》 CSCD 北大核心 2012年第5期1009-1022,共14页
我国杰出的寒区水文学家叶柏生研究员不幸因公殉职.选取了叶柏生研究员若干代表性研究成果,包括与他人的合作研究成果,重点从冰川水文、冻土水文和区域水文变化三方面总结了其对寒区水文学发展所做的创新与贡献.文章列出了每项研究成果... 我国杰出的寒区水文学家叶柏生研究员不幸因公殉职.选取了叶柏生研究员若干代表性研究成果,包括与他人的合作研究成果,重点从冰川水文、冻土水文和区域水文变化三方面总结了其对寒区水文学发展所做的创新与贡献.文章列出了每项研究成果的核心内容,并给予了简要评述.所选成果中,冰川水文方面研究涉及冰川对河川径流的调节作用、冰川径流对气候变化的响应机理等;冻土水文研究着重介绍了多年冻土变化对流域径流过程及其变化影响方面的系统性成果;区域水文变化研究方面,选取了降水观测误差修正、气候变化对区域径流的影响等方面的创新成果.这些研究成果极大地提高了我国在世界寒区水文学研究的地位,对认识寒区水文过程及气候变化对水资源的影响具有重要科学意义. 展开更多
关键词 冰川水文 冻土水文 区域水文变化 气候变化 创新与贡献 叶柏生研究员
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THE NONLINEAR NONLOCAL SINGULARLY PERTURBED PROBLEMS FOR REACTION DIFFUSION EQUATIONS 被引量:8
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作者 莫嘉琪 朱江 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2003年第5期527-531,共5页
A class of nonlinear nonlocal for singularly perturbed Robin initial boundary value problems for reaction diffusion equations is considered. Under suitable conditions, firstly, the outer solution of the original probl... A class of nonlinear nonlocal for singularly perturbed Robin initial boundary value problems for reaction diffusion equations is considered. Under suitable conditions, firstly, the outer solution of the original problem is obtained, secondly, using the stretched variable, the composing expansion method and the expanding theory of power series the initial layer is constructed, finally, using the theory of differential inequalities the asymptotic behavior of solution for the initial boundary value problems are studied and educing some relational inequalities the existence and uniqueness of solution for the original problem and the uniformly valid asymptotic estimation is discussed. 展开更多
关键词 NONLINEAR reaction diffusion singular perturbation
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Association between hepatitis B and metabolic syndrome:Current state of the art 被引量:9
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作者 Peter Jarcuska Sylvia Drazilova +2 位作者 Jan Fedacko Daniel Pella Martin Janicko 《World Journal of Gastroenterology》 SCIE CAS 2016年第1期155-164,共10页
Chronic hepatitis B(CHB)is a global health issue that increases the risk of liver cirrhosis and hepatocellular carcinoma in infected patients.Metabolic syndrome(Met S)is a disease endemic mostly to the developed count... Chronic hepatitis B(CHB)is a global health issue that increases the risk of liver cirrhosis and hepatocellular carcinoma in infected patients.Metabolic syndrome(Met S)is a disease endemic mostly to the developed countries.It is associated with high cardiovascular mortality and morbidity,diabetes mellitus as well as cancer.In this manuscript,we systematically review the published data on the relationship between Met S and CHB infection.Multiple studies have described highly variable correlations between CHB on one hand and Met S,non-alcoholic fatty liver disease and dyslipidemia on the other.No association between CHB and diabetes mellitus or atherosclerosis has been described as of now.The presence of Met S in patients infected with hepatitis B virus increases the risk of fibrosis,cirrhosis and hepatocellular carcinoma.Appropriate lifestyle,but also pharmacological interventions are needed to prevent the development of these complications. 展开更多
关键词 HEPATITIS B NONALCOHOLIC FATTY liver disease FIBROSIS CIRRHOSIS Metabolic syndrome Hepatocellularcarcinoma
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中纬度地区混合云中稳定同位素分馏的数学模拟—以乌鲁木齐降水为例(英) 被引量:12
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作者 章新平 姚檀栋 +2 位作者 田立德 刘晶淼 MasayoshiNAKAWO 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2003年第2期261-268,共8页
介绍的数学模型考虑了混合云中液、固态共存时以及冰面过饱和环境下稳定同位素的动力分馏效应。利用该数学模型,模拟了不同冷却条件下稳定同位素的温度效应。在相同的湿度条件下,湿绝热冷却过程中δ18O随温度的变化率小于等压冷却过程... 介绍的数学模型考虑了混合云中液、固态共存时以及冰面过饱和环境下稳定同位素的动力分馏效应。利用该数学模型,模拟了不同冷却条件下稳定同位素的温度效应。在相同的湿度条件下,湿绝热冷却过程中δ18O随温度的变化率小于等压冷却过程。冰面过饱和比Si的增大意味着动力分馏效应的增大。与平衡态相比,它的作用使得稳定同位素的综合分馏系数减小,从而使得降水中δ18O随温度的变化趋缓。模拟显示,湿绝热冷却过程中大气水线(MWL:=bδ18o+d)的斜率b和常数d均大于等压冷却过程。全球大气水线位于湿绝热冷却过程和等压冷却过程条件下分别模拟的两条大气水线之间。b和d的大小与Si呈正比。Si愈大,动力分馏效应愈强,b和d也愈大。反之亦然。然而,b和d的大小对云中含水量的变化具有低的敏感性。利用动力分馏模式模拟了乌鲁木齐降水中稳定同位素的变化。模拟的稳定同位素比率-温度以及δD-δ18O曲线分别与乌鲁木齐实测的稳定同位素比率-温度同归线以及大气水线有非常好的一致性。 展开更多
关键词 中纬度地区 混合云 稳定同位素 数学模型 乌鲁木齐市 降水 动力分馏效应 湿度条件
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机械活化对从复杂硫化精矿中硫代硫酸盐浸取金的影响(英文) 被引量:8
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作者 Mohsen HASHEMZADEHFINI Jana FICERIOVá +1 位作者 Emad ABKHOSHK Behrouz Karimi SHAHRAKI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第12期2744-2751,共8页
采用机械活化提高复杂硫化矿CuPbZn中金的回收。研究研磨时间、球尺寸、球料比和球磨转速对金的硫代硫酸盐浸取的影响。在最优条件下(球磨时间1h,球尺寸20mm,球料比15/1,球磨速度600r/min),矿石的非晶化度达到78%,颗粒尺寸从30μm下降到... 采用机械活化提高复杂硫化矿CuPbZn中金的回收。研究研磨时间、球尺寸、球料比和球磨转速对金的硫代硫酸盐浸取的影响。在最优条件下(球磨时间1h,球尺寸20mm,球料比15/1,球磨速度600r/min),矿石的非晶化度达到78%,颗粒尺寸从30μm下降到8um,比表面积从1.3m2/g增加到4.6m2/g,金的回收率从7.4%提高到73.26%。 展开更多
关键词 机械活化 硫代硫酸盐浸取 难处理矿 提金
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Characterization of Cellulosic Fibers by FTIR Spectroscopy for Their Further Implementation to Building Materials 被引量:4
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作者 Viola Hospodarova Eva Singovszka Nadezda Stevulova 《American Journal of Analytical Chemistry》 2018年第6期303-310,共8页
Nowadays, the material recycling is a growing trend in development of building materials and therefore using of secondary raw materials for production new building materials is in accordance with sustainable developme... Nowadays, the material recycling is a growing trend in development of building materials and therefore using of secondary raw materials for production new building materials is in accordance with sustainable development in civil engineering. Therefore, it is increasingly becoming crucial to accelerate the transition from application of non-renewable sources of raw materials to renewable raw materials. One fast renewable resource is natural plant fibers. The use of the cellulosic fibers as environmentally friendly material in building products contributes to the environmental protection and saves non-renewable resources of raw materials. Wood fibers and recycled cellulose fibers of waste paper appear as suited reinforcing elements for cement-based materials. In this paper, there is used application of Fourier transform infrared spectroscopy (FTIR) on cellulose fibers coming from different sources. FTIR spectra of cellulose fiber samples are investigated and compared with reference sample of cellulose. 展开更多
关键词 RENEWABLE RAW Materials CELLULOSE Fibers INFRARED SPECTROSCOPY
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Doping effects of manganese on the catalytic performance and structure of NiMgO catalysts for controllabe synthesis of multi-walled carbon nanotubes 被引量:4
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作者 Maofei Ran Wei Chu +3 位作者 Yan Liu Dong Liu Chang Zhang Jiae Zheng 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2014年第6期781-788,共8页
Doping effects of manganese (Mn) on catalytic performance and structure evolution of NiMgO catalysts for synthesis of multi-walled carbon nanotubes (MWCNTs) from methane were investigated for the first time. Addit... Doping effects of manganese (Mn) on catalytic performance and structure evolution of NiMgO catalysts for synthesis of multi-walled carbon nanotubes (MWCNTs) from methane were investigated for the first time. Addition of Mn in NiMgO catalyst can greatly improve the MWCNTs yield. Mno.2NiMgO catalyst among the tested ones gives the highest MWCNTs yield as 2244%, which is two times higher than that of the catalyst without Mn. The structure evolution, reduction behaviors and surface chemical properties of MnNiMgO catalysts with various Mn contents were studied in detail. It was found that the stable solid solution of NiMgO2 formed in NiMgO catalyst was disturbed by the addition of Mn. Instead, another solid solution of MnMg608 is formed. More amount of Ni can be reduced and dispersed on the catalyst surface to be acted as active sites. Importantly, the changes of Ni content on the surface are correlated with the Ni particle size and the outer diameter of MWCNTs, suggesting the controllable synthesis of MWCNTs over MnNiMgO catalysts. 展开更多
关键词 doping effect MANGANESE NiMgO catalyst controllable synthesis carbon nanotubes
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Neuroprotective agents effective against radiation damage of central nervous system 被引量:2
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作者 Mária Lalkovičová 《Neural Regeneration Research》 SCIE CAS CSCD 2022年第9期1885-1892,共8页
Ionizing radiation caused by medical treatments,nuclear events or even space flights can irreversibly damage structure and function of brain cells.That can result in serious brain damage,with memory and behavior disor... Ionizing radiation caused by medical treatments,nuclear events or even space flights can irreversibly damage structure and function of brain cells.That can result in serious brain damage,with memory and behavior disorders,or even fatal oncologic or neurodegenerative illnesses.Currently used treatments and drugs are mostly targeting biochemical processes of cell apoptosis,radiation toxicity,neuroinflammation,and conditions such as cognitive-behavioral disturbances or others that result from the radiation insult.With most drugs,the side effects and potential toxicity are also to be considered.Therefore,many agents have not been approved for clinical use yet.In this review,we focus on the latest and most effective agents that have been used in animal and also in the human research,and clinical treatments.They could have the potential therapeutical use in cases of radiation damage of central nervous system,and also in prevention considering their radioprotecting effect of nervous tissue. 展开更多
关键词 ANTIOXIDANTS biomedical neuroprotectants central nervous system ionizing radiation neuroprotection radiation injury radiomitigators radioprotectants RADIOPROTECTION THERAPEUTICS
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硬帆辅助推进散货船的稳定性和动力性能综合分析 被引量:2
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作者 Kirill Sazonov Aleksei Dobrodeev 《Journal of Marine Science and Application》 CSCD 2021年第3期446-455,共10页
Large size vessels sailing in continuous level ice and broken ice of high concentration are mostly assisted by icebreakers.This is done in order to provide for fast transportation through the North Sea Route and safe ... Large size vessels sailing in continuous level ice and broken ice of high concentration are mostly assisted by icebreakers.This is done in order to provide for fast transportation through the North Sea Route and safe operation in extreme ice conditions.Currently,new large size gas and oil carriers and container ships are being designed and built with beams much greater than the beams of existing icebreakers.At the same time,no mathematical description exists for the breaking mechanism of ice channel edges,when such vessels move under icebreaker escort.This paper suggests a simple method for assessment of the ice resistance in the case of a large ship running in an icebreaker channel;the method is based on modification of well-known semi-empirical methods for calculation of the ice resistance to ships in level and broken ice.The main feature of the proposed calculation scheme consists in that different methods are applied to estimate the ice resistance in broken ice and due to breaking of level ice edges.The combination of these methods gives a deliverable ice resistance of a large size vessel moving under icebreaker assistance in a newly made ice channel.In general,proposed method allows to define the speed of a carrier moving in an ice channel behind a modern linear icebreaker and could be applied at the ship design stage and during development of the marine transportation system.The paper also discusses the ways for further refinement of the assessment procedure suggested. 展开更多
关键词 Ice resistance Icebreaker assistance Large size vessels Narrow ice channel Northern Sea Route Ice model tests
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Observation of ocean current response to 1998 Hurricane Georges in the Gulf of Mexico 被引量:20
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作者 ZHENG Quanan LAI Ronald J +2 位作者 HUANG Nortlen E PAN Jiayi LIU W Timothy 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2006年第1期1-14,共14页
The ocean current response to a hurricane on the shelf-break is examined. The study area is the DeSoto Canyon in the northeast Gulf of Mexico, and the event is the passage of 1998 Hurricane Georges with a maximum wind... The ocean current response to a hurricane on the shelf-break is examined. The study area is the DeSoto Canyon in the northeast Gulf of Mexico, and the event is the passage of 1998 Hurricane Georges with a maximum wind speed of 49 m/s. The data sets used for analysis consist of the mooring data taken by the Field Program of the DeSoto Canyon Eddy Intrusion Study, and simultaneous winds observed by NOAA (National Oceanic and Atmospheric Administration) Moored Buoy 42040. Time-depth ocean current energy density images derived from the observed data show that the ocean currents respond almost immediately to the hurricane with important differences on and offthe shelf. On the shelf, in the shallow water of 100 m, the disturbance penetrates rapidly downward to the bottom and forms two energy peaks, the major peak is located in the mixed layer and the secondary one in the lower layer. The response dissipates quickly after external forcing disappears. Offthe shelf, in the deep water, the major disturbance energy seems to be trapped in the mixed layer with a trailing oscillation; although the disturbance signals may still be observed at the depths of 500 and 1 290 m. Vertical dispersion analysis reveals that the near-initial wave packet generated offthe shelf consists of two modes. One is a barotropic wave mode characterized by a fast decay rate of velocity amplitude of 0.020 s^-, and the other is baroclinic wave mode characterized by a slow decay rate of 0.006 9 s^-1. The band-pass-filtering and empirical function techniques are employed to the frequency analysis. The results indicate that ialf frequencies shift above the local inertial frequency. On the shelf, the average frequency is 1.04fin the mixed layer, close to the diagnosed frequency of the first baroclinic mode, and the average frequency increases to 1.07fin the thermocline. Offthe shelf, all frequencies are a little smaller than the diagnosed frequency of the first mode. The average frequency decreases from 1.035fin the mixed layer to 1.02fin the thermocline, implying a trend for the shift in frequency of the oscillations towards f with the depth. 展开更多
关键词 shelf dynamics HURRICANE ocean current air-sea interaction
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Possible Impacts of Barents Sea Ice on the Eurasian Atmospheric Circulation and the Rainfall of East China in the Beginning of Summer 被引量:4
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作者 王嘉 郭裕福 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2004年第4期662-674,共13页
Possible influences of the Barents Sea ice anomalies on the Eurasian atmospheric circulation and the East China precipitation distribution in the late spring and early summer (May-June) are investigated by analyzing t... Possible influences of the Barents Sea ice anomalies on the Eurasian atmospheric circulation and the East China precipitation distribution in the late spring and early summer (May-June) are investigated by analyzing the observational data and the output of an atmospheric general circulation model (AGCM). The study indicates that the sea ice condition of the Barents Sea from May to July may be interrelated with the atmospheric circulation of June. When there is more than average sea ice in the Barents Sea, the local geopotential height of the 500-hPa level will decrease, and the same height in the Lake Baikal and Okhotsk regions will increase and decrease respectively to form a wave-chain structure over North Eurasia. This kind of anomalous height pattern is beneficial to more precipitation in the south part of East China and less in the north. 展开更多
关键词 sea ice the Barents Sea Eurasian atmospheric circulation East China precipitation
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