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Fast density peak-based clustering algorithm for multiple extended target tracking 预览
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作者 SHEN Xinglin SONG Zhiyong +1 位作者 FAN Hongqi FU Qiang 《系统工程与电子技术:英文版》 SCIE EI CSCD 2019年第3期435-447,共13页
The key challenge of the extended target probability hypothesis density (ET-PHD) filter is to reduce the computational complexity by using a subset to approximate the full set of partitions. In this paper, the influen... The key challenge of the extended target probability hypothesis density (ET-PHD) filter is to reduce the computational complexity by using a subset to approximate the full set of partitions. In this paper, the influence for the tracking results of different partitions is analyzed, and the form of the most informative partition is obtained. Then, a fast density peak-based clustering (FDPC) partitioning algorithm is applied to the measurement set partitioning. Since only one partition of the measurement set is used, the ET-PHD filter based on FDPC partitioning has lower computational complexity than the other ET-PHD filters. As FDPC partitioning is able to remove the spatially close clutter-generated measurements, the ET-PHD filter based on FDPC partitioning has good tracking performance in the scenario with more clutter-generated measurements. The simulation results show that the proposed algorithm can get the most informative partition and obviously reduce computational burden without losing tracking performance. As the number of clutter-generated measurements increased, the ET-PHD filter based on FDPC partitioning has better tracking performance than other ET-PHD filters. The FDPC algorithm will play an important role in the engineering realization of the multiple extended target tracking filter. 展开更多
关键词 FAST DENSITY peak-based clustering (FDPC) MULTIPLE extended target partition probability hypothesis DENSITY (PHD) filter track.
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Enhanced Roles of Carbon Architectures in High?Performance Lithium?Ion Batteries
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作者 Lu Wang Junwei Han +2 位作者 Debin Kong Ying Tao Quan-Hong Yang 《纳微快报:英文版》 CAS CSCD 2019年第1期78-100,共23页
Lithium-ion batteries(LIBs),which are high-energydensity and low-safety-risk secondary batteries,are underpinned to the rise in electrochemical energy storage devices that satisfy the urgent demands of the global ener... Lithium-ion batteries(LIBs),which are high-energydensity and low-safety-risk secondary batteries,are underpinned to the rise in electrochemical energy storage devices that satisfy the urgent demands of the global energy storage market.With the aim of achieving high energy density and fast-charging performance,the exploitation of simple and low-cost approaches for the production of high capacity,high density,high mass loading,and kinetically ion-accessible electrodes that maximize charge storage and transport in LIBs,is a critical need.Toward the construction of high-performance electrodes,carbons are promisingly used in the enhanced roles of active materials,electrochemical reaction frameworks for high-capacity noncarbons,and lightweight current collectors.Here,we review recent advances in the carbon engineering of electrodes for excellent electrochemical performance and structural stability,which is enabled by assembled carbon architectures that guarantee sufficient charge delivery and volume fluctuation buffering inside the electrode during cycling.Some specific feasible assembly methods,synergism between structural design components of carbon assemblies,and electrochemical performance enhancement are highlighted.The precise design of carbon cages by the assembly of graphene units is potentially useful for the controlled preparation of high-capacity carbon-caged noncarbon anodes with volumetric capacities over 2100 mAh cm?3.Finally,insights are given on the prospects and challenges for designing carbon architectures for practical LIBs that simultaneously provide high energy densities(both gravimetric and volumetric)and high rate performance. 展开更多
关键词 Lithium?ion BATTERY Carbon architecture Energy DENSITY Power DENSITY Assembly
Asymmetric supercapacitors based on high capacitance Ni6MnO8 and graphene
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作者 Mingyang Zeng Li Zhang +3 位作者 Dandan Wu Jun Ma Cao Zhang Shujuan Li 《中国化学快报:英文版》 SCIE CAS CSCD 2019年第6期1329-1334,共6页
Supercapacitors with high energy density and high power density have attracted numerous attentions. Here, we successfully synthesized Ni6MnO8 material by a fast, facile, and cost-effective method, which the area speci... Supercapacitors with high energy density and high power density have attracted numerous attentions. Here, we successfully synthesized Ni6MnO8 material by a fast, facile, and cost-effective method, which the area specific capacitance was found to be as high as 1113 mF/cm^2 at a current density of 1 mA/cm^2. Further, the asymmetric supercapacitor was assembled by using Ni6MnO8 as the positive electrode and graphene as the negative electrode with an operation potential from 0 to 1.4 V. It exhibited an area specific capacitance of 69.1m F/cm^2 at 0.5 mA/cm^2 and stable cycling performance which presented about 80% capacitance retention after 5000 cycles at 5 mA/cm^2. The energy density of graphene//Ni6MnO8 supercapacitors was calculated to be 18.81 mWh/cm^2 at a power density of 350.1 mW/cm^2 and still remained 5.8 mWh/cm^2 at a power density of 6990.7 mW/cm^2, meaning that the asymmetric supercapacitor combine excellent power density and energy density. 展开更多
关键词 Ni6MnO8 ELECTRODE ASYMMETRIC SUPERCAPACITORS Power DENSITY Energy DENSITY
Words of the Editor-in-Chief——some ideas about the comments and discussions of hyperpycnal flows and hyperpycnites
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作者 Zeng-Zhao Feng 《古地理学报:英文版》 CSCD 2019年第3期301-305,共5页
I basically agree with the viewpoints of Shanmugam(Journal of Palaeogeography 7(3):197-238,2018)and Zavala(Journal of Palaeogeog raphy 8(3):306-313,2019)who cited,refined and interpreted the definitions of hypopycnal ... I basically agree with the viewpoints of Shanmugam(Journal of Palaeogeography 7(3):197-238,2018)and Zavala(Journal of Palaeogeog raphy 8(3):306-313,2019)who cited,refined and interpreted the definitions of hypopycnal flow,homopycnal flow and hyperpycnal flow.I appreciate two typical case studies of hyperpycnal flows induced by the Yellow River and Yangtze River,and the Gaoping River.The former is a normal type while the latter is catastrophic.They make up a complete knowledge about hyperpycnal flows and hyperpycnites.According to the interpretation of the word "hyperpycnal" from Greek to English,the "hypopycnal flow" should be "less density flow" or "lower density flow"("低密度流"),the "homopycnal flow" should be "equal density flow"("等密度流"),and the"hyperpycnal flow" should be "higher density flow" or "over density flow"("高密度流" or "超密度流").Some geologists called the "hypopycnal flow" as "异轻流"("abnormally light flow")and called the "hyperpycnal flow" as"异重流"("abnormally heavy flow").There are at least more than 10 names or terms about the "density flows" and the "deposits of density flows".It is a problem indeed.In addition,the density could be changed by salinity,temperature and pressure of water.Therefore,the term "density flow" may be problematic either.Another problem is that reliable and irrefutable identification markers of ancient heperpycnites are lacking.We should observe the policy of "A hundred flowers blossom and a hundred schools of thought contend" to discuss these problems and to promote progress and development of hyperpycnal flows and hyperpycnites. 展开更多
关键词 Hyperpycnal FLOWS Hyperpycnites DENSITY FLOWS Definitions and NAMES of DENSITY FLOWS and their deposits Identification markers of an cient hyperpycnites A hundred FLOWERS blossom and a hundred schools of thought CONTEND
Fabricating high-performance sodium ion capacitors with P2-Na0.67Co0.5Mn0.5O2 and MOF-derived carbon 预览
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作者 Haichen Gu Lingjun Kong +3 位作者 Huijuan Cui Xianlong Zhou Zhaojun Xie Zhen Zhou 《能源化学:英文版》 SCIE EI CAS CSCD 2019年第1期79-84,共6页
Sodium ion capacitors(SICs)have been considered as a kind of promising devices to achieve both high power and energy density.However,it is still a challenge to achieve high energy output at elevated power delivery due... Sodium ion capacitors(SICs)have been considered as a kind of promising devices to achieve both high power and energy density.However,it is still a challenge to achieve high energy output at elevated power delivery due to the poor rate capability of battery-type electrode materials and the kinetic mismatch with capacitor-type electrode materials.In this work,to fabricate SICs,P2-Na0.67Co0.5Mn0.5O2(P2-NCM)was chosen as the battery-type cathode material,and a typical metal-organic framework(MOF)material,zeolitic imidazolate framework-8(ZIF-8)derived carbon(ZDC)was utilized as the capacitor-type anode material.Due to the kinetic match and high-rate performance of both electrodes,the ZDC//P2-NCM SICs exhibited an energy output of 18.8 Wh kg^-1 at a high power delivery of 12.75 kW kg^-1. 展开更多
关键词 Energy DENSITY Power DENSITY P2-phase material Zeolitic IMIDAZOLATE framework-8 Sodium ion capacitors
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利用小核磁法测定聚乙烯密度 预览
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作者 柳盛 郭凡 +3 位作者 王会能 王学智 刘鹏 刘文才 《合成树脂及塑料》 CAS 北大核心 2019年第2期62-66,共5页
考察了小核磁法测定聚乙烯密度的重复性及准确性,并分别采用小核磁法与密度梯度柱法测试了高密度聚乙烯、低密度聚乙烯和线型低密度聚乙烯的密度。结果表明,采用小核磁法与密度梯度柱法测定聚乙烯密度值之差为:线型低密度聚乙烯粒料≤0.... 考察了小核磁法测定聚乙烯密度的重复性及准确性,并分别采用小核磁法与密度梯度柱法测试了高密度聚乙烯、低密度聚乙烯和线型低密度聚乙烯的密度。结果表明,采用小核磁法与密度梯度柱法测定聚乙烯密度值之差为:线型低密度聚乙烯粒料≤0.0001g/cm^3,线型低密度聚乙烯粉料≤0.0002g/cm^3;低密度聚乙烯粒料≤0.0001g/cm^3,低密度聚乙烯粉料≤0.0002g/cm^3,高密度聚乙烯粒料≤0.0001g/cm^3,高密度聚乙烯粉料≤0.0004g/cm^3。确定小核磁法测定聚乙烯密度满足密度梯度柱法要求的精密度及准确度,两种方法可以互相替换。小核磁法测定聚乙烯密度的主要影响因素有试样含水、沾油或混入其他杂质,试样预热时间不足30min或磁体衰减,同时提出了相应的解决措施。 展开更多
关键词 聚乙烯 密度 小核磁法 密度梯度柱法 粒料 粉料
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终碾温度对沥青混凝土压实性的影响研究
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作者 杨乐天 何建新 开鑫 《粉煤灰综合利用》 CAS 2019年第1期10-12,27共4页
为了研究不同终碾温度对沥青混凝土压实性能的影响,本文以90℃~160℃区间为例,通过网篮法以及马歇尔试验研究,分析不同终碾温度下沥青混凝土试件的密度、孔隙率、稳定度和流值的影响情况。结果表明:随着终碾温度的降低,沥青混凝土的孔... 为了研究不同终碾温度对沥青混凝土压实性能的影响,本文以90℃~160℃区间为例,通过网篮法以及马歇尔试验研究,分析不同终碾温度下沥青混凝土试件的密度、孔隙率、稳定度和流值的影响情况。结果表明:随着终碾温度的降低,沥青混凝土的孔隙率增加明显,马歇尔试件稳定度下降,流值增大;终碾温度在100℃时,沥青混凝土的孔隙率可满足小于2%的要求;在正反各70次击实次数时,仅90℃的沥青混合料能满足低于2%孔隙率的要求。研究成果可为冬季沥青混凝土心墙坝加快施工速度、延长施工周期、控制施工质量提供理论依据和技术支持。 展开更多
关键词 沥青混凝土 网篮法 密度 孔隙率
Onshore-offshore wind energy resource evaluation based on synergetic use of multiple satellite data and meteorological stations in Jiangsu Province,China
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作者 Xianglin WEI Yuewei DUAN +2 位作者 Yongxue LIU Song JIN Chao SUN 《地球科学前沿:英文版》 SCIE CAS CSCD 2019年第1期132-150,共19页
The demand for efficient and cost-effective renewable energy is increasing as traditional sources of energy such as oil,coal,and natural gas,can no longer satisfy growing global energy demands.Among renewable energies... The demand for efficient and cost-effective renewable energy is increasing as traditional sources of energy such as oil,coal,and natural gas,can no longer satisfy growing global energy demands.Among renewable energies,wind energy is the most prominent due to its low, manageable impacts on the local environment.Based on meteorological data from 2006 to 2014 and multi-source satellite data (i.e.,Advanced Scatterometer,Quick Scatterometer,and Windsat)from 1999 to 2015,an assessment of the onshore and offshore wind energy potential in Jiangsu Province was performed by calculating the average wind speed,average wind direction,wind power density, and annual energy production (AEP).Results show that Jiangsu has abundant wind energy resources,which increase from inland to coastal areas.In-onshore areas, wind power density is predominantly less than 200 W/m^2, while in offshore areas,wind power density is concentrates in the range of 328-500 W/m^2.Onshore areas comprise more than 13,573.24 km^2,mainly located in eastern coastal regions with good wind farm potential The total wind power capacity in onshore areas could be as much as 2.06×10^5 GWh.Meanwhile,offshore wind power generation in Jiangsu Province is calculated to reach 2×10^6 GWh, which is approximately four times the electricity demand of the entire Jiangsu Province.This study validates the effective application of Advanced Scatterometer,Quick Scatterometer,and Windsat data to coastal wind energy monitoring in Jiangsu.Moreover,the methodology used in this study can be effectively applied to other similar coastal zones. 展开更多
关键词 WIND ENERGY RESOURCE WIND power DENSITY ASCAT QUIKSCAT Windsat
行距及密度对夏玉米产量及其构成因素的影响 预览
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作者 崔丽娜 李令伟 +4 位作者 崔延臣 张钰 禹光媛 杨连俊 董树亭 《安徽农业科学》 CAS 2019年第13期29-31,34共4页
以德利农7号为试验材料,研究不同行距及密度对夏玉米产量及其相关因素的影响。试验结果表明,不同行距条件下,玉米产量随着密度的增加规律不一致。在60和70cm行距下,玉米产量随着密度的增加呈先增加后减少的趋势。穗数、千粒重和产量方... 以德利农7号为试验材料,研究不同行距及密度对夏玉米产量及其相关因素的影响。试验结果表明,不同行距条件下,玉米产量随着密度的增加规律不一致。在60和70cm行距下,玉米产量随着密度的增加呈先增加后减少的趋势。穗数、千粒重和产量方差分析显示,行距、密度及行距与密度的交互效应均达极显著水平;穗粒数方差分析结果显示,仅有密度差异的处理达到显著水平。在75和80cm行距处理下,玉米产量随着密度的增加而增加。行距75cm、密度90000株/hm2处理的玉米产量最大。 展开更多
关键词 行距 密度 玉米 产量
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超声波在石油产品检测中的应用及研究进展 预览
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作者 周胜友 沈宏云 +1 位作者 史永刚 熊刚 《化学工程师》 CAS 2019年第5期65-69,共5页
简要分析了超声波检测原理,注重介绍了超声波在检测石油产品密度、粘度和低温性能中的应用。并展望了超声在石油产品检测中的发展,指出应用超声技术检测石油产品具有无损检测、快速响应、实时在线和精确检测等特点。
关键词 石油产品 超声波 密度 粘度 低温性能
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密度·播期和氮肥用量对小麦产量与品质的影响 预览
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作者 谭娟 王竟绍 董伟 《安徽农业科学》 CAS 2019年第15期35-36,共2页
对比分析了不同密度、播期及氮肥条件下小麦“良星99”产量与品质的差异,从而获得小麦适宜播期、密度及氮肥用量。结果表明,密度为影响小麦产量、穗粒数、亩穗数的重要因素,播期主要影响小麦产量与亩穗数,氮肥为影响小麦千粒重、亩穗数... 对比分析了不同密度、播期及氮肥条件下小麦“良星99”产量与品质的差异,从而获得小麦适宜播期、密度及氮肥用量。结果表明,密度为影响小麦产量、穗粒数、亩穗数的重要因素,播期主要影响小麦产量与亩穗数,氮肥为影响小麦千粒重、亩穗数及籽粒蛋白含量、沉降值及湿面筋含量的关键因素。小麦“良星99”最佳播期为10月10日,适宜种植密度与氮肥用量分别为基本苗300万/hm^2、氮肥375kg/hm^2。 展开更多
关键词 小麦 产量 品质 密度 播期 氮肥用量
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高沙土地区泰花8号单粒播种密度试验研究 预览
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作者 王书勤 谢吉先 +1 位作者 韩桂琴 季国民 《安徽农业科学》 CAS 2019年第15期37-39,共3页
在高沙土地区生态条件下,以泰花8号为试验材料连续2年在大田条件下采用垄作覆膜双行栽培进行试验,研究了单粒播种密度对泰花8号产量、生育期、叶面积、叶面积指数和植株性状的影响。结果表明,当株距控制在11~13cm时,泰花8号产量最高、... 在高沙土地区生态条件下,以泰花8号为试验材料连续2年在大田条件下采用垄作覆膜双行栽培进行试验,研究了单粒播种密度对泰花8号产量、生育期、叶面积、叶面积指数和植株性状的影响。结果表明,当株距控制在11~13cm时,泰花8号产量最高、植株性状最好、群体最合理。 展开更多
关键词 泰花8号 单粒播种 密度 生长特性 产量
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Experimental determination of distributions of soot particle diameter and number density by emission and scattering techniques
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作者 柳华蔚 郑树 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第1期400-405,共6页
A diagnostics method was presented that uses emission and scattering techniques to simultaneously determine the distributions of soot particle diameter and number density in hydrocarbon flames. Two manta G-504 C camer... A diagnostics method was presented that uses emission and scattering techniques to simultaneously determine the distributions of soot particle diameter and number density in hydrocarbon flames. Two manta G-504 C cameras were utilized for the scattering measurement, with consideration of the attenuation effect in the flames according to corresponding absorption coefficients. Distributions of soot particle diameter and number density were simultaneously determined using the measured scattering coefficients and absorption coefficients under multiple wavelengths already measured with a SOC701 V hyper-spectral imaging device, according to the Mie scattering theory. A flame was produced using an axisymmetric laminar diffusion flame burner with 194 mL/min ethylene and 284 L/min air, and distributions of particle diameter and number density for the flame were presented. Consequently, the distributions of soot volume fraction were calculated using these two parameters as well, which were in good agreement with the results calculated according to the Rayleigh approximation,demonstrating that the proposed diagnostic method is capable of simultaneous determination of the distributions of soot particle diameter and number density. 展开更多
关键词 SOOT PARTICLE DIAMETER SOOT PARTICLE NUMBER density SOOT volume FRACTION SCATTERING measurement
2018年寿光市洪灾后6乡镇蝇类密度监测
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作者 孙桂兰 《预防医学论坛》 2019年第5期394-396,共3页
目的了解寿光市2018年8月洪灾后蝇类密度情况,评价短期内洪灾对其消长的影响,为下一步全面实施蝇类防控措施提供依据。方法分别于9月1~2、8日先后对受灾最严重的6乡镇蝇密度采用目测法进行2次统一监测。结果第1次监测:成蝇密度平均为16... 目的了解寿光市2018年8月洪灾后蝇类密度情况,评价短期内洪灾对其消长的影响,为下一步全面实施蝇类防控措施提供依据。方法分别于9月1~2、8日先后对受灾最严重的6乡镇蝇密度采用目测法进行2次统一监测。结果第1次监测:成蝇密度平均为16.54只/m~2,其中进水村为19.23只/m~2,未进水村为13.85只/m~2;垃圾堆放场所密度最高为42.79只/m~2。蝇幼虫孳生率为5.51%,其中进水村为5.21%,未进水村为5.94%。第2次监测:成蝇密度平均为1.89只/m~2,其中进水村为1.25只/m~2,未进水村为2.53只/m~2,垃圾堆放场所密度最高为3.46只/m~2。结论洪灾引起蝇密度异常升高(结合2017年同期成蝇密度7.83只/m~2),灾后及时采取蝇类防控措施效果明显。 展开更多
关键词 洪灾 蝇类 密度 防控措施
玉米新品种鑫瑞36耐密性研究 预览
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作者 赵红克 赵清纯 《作物研究》 2019年第2期114-116,共3页
调查了玉米新品种鑫瑞36在不同种植密度下的农艺性状及产量与产量要素,结果表明,在其他条件一致的情况下,鑫瑞36在种植密度为75000株/hm^2左右时,其产量水平表现最高。
关键词 玉米 栽培 密度 鑫瑞36
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中低温煤焦油窄馏分密度和黏度随温度的变化规律
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作者 胡发亭 朱肖曼 +1 位作者 李军芳 吴艳 《煤炭技术》 CAS 2019年第4期142-144,共3页
以中低温煤焦油为原料,经实沸点蒸馏切割成17个窄馏分,对每个馏分测定其在不同温度下的密度,得出密度随温度的升高而变小,具有很好的线性关系,经过理论计算和推导,得出体胀系数E和线性系数也呈线性关系。依据每个馏分段在不同温度下的... 以中低温煤焦油为原料,经实沸点蒸馏切割成17个窄馏分,对每个馏分测定其在不同温度下的密度,得出密度随温度的升高而变小,具有很好的线性关系,经过理论计算和推导,得出体胀系数E和线性系数也呈线性关系。依据每个馏分段在不同温度下的运动黏度,通过计算得出动力黏度,发现动力黏度随着温度的升高而降低,而且符合Vogel关系式。 展开更多
关键词 中低温煤焦油 实沸点蒸馏 窄馏分 密度 黏度
核电主泵铸造泵壳的国产化研制 预览
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作者 王平 唐贤其 +2 位作者 李莉 段红玲 陈冲 《大型铸锻件》 2019年第2期10-12,15共4页
结合计算机凝固过程仿真模拟技术,对核电主泵铸造泵壳的关键铸造技术进行研究,解决了奥氏体-铁素体不锈钢核电铸造泵壳需整体RT检测的问题,并通过确定合适的材料配比和热处理工艺参数,保证铸造泵壳所需的理化性能及金相组织构成,完成了... 结合计算机凝固过程仿真模拟技术,对核电主泵铸造泵壳的关键铸造技术进行研究,解决了奥氏体-铁素体不锈钢核电铸造泵壳需整体RT检测的问题,并通过确定合适的材料配比和热处理工艺参数,保证铸造泵壳所需的理化性能及金相组织构成,完成了首台核电主泵铸造泵壳的国产化研制。 展开更多
关键词 铸造泵壳 致密性 成分和组织控制
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离子液体[emim]Ac密度和电导率的实验与理论研究 预览
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作者 何丽娟 陈帅帅 +2 位作者 李松波 刘素霞 田宝云 《应用化工》 CAS CSCD 北大核心 2019年第4期798-800,共3页
对离子液体[emim]Ac的密度和电导率进行了实验测定与理论模型关联。结果表明,离子液体[emim]Ac的密度随温度的升高逐渐减小,当温度范围为298.15~338.15 K时,[emim]Ac的密度值变化范围为1 072~ 1 024 kg/m 3;离子液体[emim]Ac的电导率随... 对离子液体[emim]Ac的密度和电导率进行了实验测定与理论模型关联。结果表明,离子液体[emim]Ac的密度随温度的升高逐渐减小,当温度范围为298.15~338.15 K时,[emim]Ac的密度值变化范围为1 072~ 1 024 kg/m 3;离子液体[emim]Ac的电导率随温度的升高逐渐增大,当温度范围为298.15~338.15 K时,[emim]Ac的电导率值变化范围为0.369~0.983 S/m;通过比较离子液体[emim]Ac密度及电导率的理论模型关联数据与实验测定数据,得出[emim]Ac密度及电导率的理论模型关联平均相对偏差和最大相对偏差分别为:0.82%, 2.65%和1.43%,2.91%,关联结果与实验测定结果一致,故认为所选模型可用于实验数据关联。 展开更多
关键词 [emim]Ac 密度 电导率 实验测定 模型关联
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What is the mass of loess in the Loess Plateau of China?
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作者 Yuanjun Zhu Xiaoxu Jia +1 位作者 Jiangbo Qiao Ming’an Shao 《科学通报:英文版》 SCIE EI CSCD 2019年第8期534-539,共6页
The Loess Plateau of China(LP) has the largest and thickest loess deposits in the world. Quantifying the amount of loess in the LP is crucial for investigating the accumulation and erosion of loess, and determining th... The Loess Plateau of China(LP) has the largest and thickest loess deposits in the world. Quantifying the amount of loess in the LP is crucial for investigating the accumulation and erosion of loess, and determining the regional soil and water resource capacity. We used loess thickness data, a pedotransfer function for bulk density(BD), and the clay content data observed in 242 sites across the LP to derive the BD of loess and then estimate the loess mass and its distribution across the LP. The results indicated that the average BD of loess between the surface and bedrock is 1.58 g cm-3, varying from 1.18 to 1.87 g cm-3.The total loess mass is approximately 5.45 ? 1013 t, and the average loess mass over an area of 1 m2 is 169 t, ranging from 1.36 to 585 t. The greatest mass of loess is in the south-central of the LP while the lowest mass of loess is in the northwest and river valley areas. Our estimate of loess mass provides key data for calculating water, carbon, and nutrient storages in the LP, which improves our understanding of soil-water processes and ecohydrological systems in this landscape. 展开更多
关键词 The LOESS PLATEAU LOESS MASS Pedotransfer function Soil EROSION BULK density
Utilization of the superior properties of highly mesoporous PVP modified NiCo2O4 with accessible 3D nanostructure and flower-like morphology towards electrochemical methanol oxidation reaction 预览
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作者 Gracita M.Tomboc Medhen W.Abebe +1 位作者 Anteneh F.Baye Hern Kim 《能源化学:英文版》 SCIE EI CAS CSCD 2019年第2期136-146,共11页
Up to this date,researchers are still facing difficulties to expand the technology of direct methanol fuel cells(DMFCs) because of the high overpotential required to oxidize the methanol and its relatively poor perfor... Up to this date,researchers are still facing difficulties to expand the technology of direct methanol fuel cells(DMFCs) because of the high overpotential required to oxidize the methanol and its relatively poor performance due to CO poisoning of the leading-high cost anode catalyst.In line with this,we have successfully modified the morphological structure and composition of low cost cobalt based-metal oxides,MCo2O4(M = Zn and Ni),with the simple and noble use of polyvinyl pyrrolidone(PVP) as growth modifier and surface stabilizer during the synthesis of nanoparticles in our previous reports,which shown high electrocatalytic activity and strong stability.Due to the good performance of our PVP modified MCo2O4 towards pseudocapacitor and oxygen evolution reaction applications,we decided to extend our research study to methanol oxidation reaction.Remarkably,PVP modified Ni Co2O4 electrode directly grown on nickel foam substrate via a simple hydrothermal process exhibited better performance compared with PVP modified ZnCo2O4 and NiCo2O4 without PVP.It had obtained a remarkably low onset potential of 0.285 V and high current density of 280 m A cm-2,and shown great stability and high poison tolerance during a continuous CV cycling and Chronoamperometry test,which attained high efficiency of 86.86%and 98.52%,respectively.These positive results of PVP modified Ni Co2O4 electrode towards MOR might be attributed to its hierarchical 3 D nanostructures with highly mesoporous surface and large surface area which may have provided numerous electroactive sites,and the exceptional corrosion stability of Ni Co2O4 electrode in alkaline solution. 展开更多
关键词 NiCo2O4 3D NANOSTRUCTURE ELECTROCHEMICAL METHANOL oxidation Current density
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