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流变与传承——秦汉时期“伏日”考论 被引量:1
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作者 魏永康 《古代文明》 CSSCI 2013年第4期58-64,111,共7页
"伏日"的习俗有古老的渊源,秦德公"初伏"仅指秦国第一次举行祭祀活动。作为节令的"伏日",专指"初伏"那一天;"三伏"的具体时间受到夏至、立秋的日期和其所在"庚日"与夏至... "伏日"的习俗有古老的渊源,秦德公"初伏"仅指秦国第一次举行祭祀活动。作为节令的"伏日",专指"初伏"那一天;"三伏"的具体时间受到夏至、立秋的日期和其所在"庚日"与夏至、立秋之时间间隔的影响,每年均不固定。《后汉书》所记"初令尽闭门"与《二年律令》所载"伏闭门"并不矛盾,前者只是汉和帝在执政期间初次施行。虽然在汉初和东汉都有"伏闭门"的习俗,但前者是当时政治环境与人口控制政策的产物,而后者则主要受阴阳五行思想的影响。 展开更多
关键词 择伏 闭门 变迁
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Selective determination of trace cobalt in zinc electrolytes by second-derivative catalytic polarography
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作者 ZHU Hong-qiu DU Juan +2 位作者 LI Yong-gang ZHANG Tai-ming CHENG Fei 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第1期207-218,共12页
We report herein a highly selective method for directly determining the trace Co^2+in highly concentrated zinc electrolyte.This novel method is based on a second derivative wave of catalytic adsorptive polarography ge... We report herein a highly selective method for directly determining the trace Co^2+in highly concentrated zinc electrolyte.This novel method is based on a second derivative wave of catalytic adsorptive polarography generated by complexing Co^2+with dimethylglyoxime and nitrite onto a dropping mercury electrode.By employing a medium with NH3-NH4Cl buffer,DMG and NaNO2 during determining the trace Co^2+,any interferences of highly concentrated Zn^2+and other coexisting metal ions in the electrolyte are completely eliminated due to the selective masking effect of EDTA.When the concentration of Co^2+is within 1.0×10^–10–3.2×10^–7 mol/L range,it shows a good linear relationship with the current peak.Detection limit is 1.0×10^–11 mol/L,and RSD≤2.7%for six successive assays.We have compared the efficiency of the current method to that obtained by cobalt nitroso-R-salt spectrophotometry,and the absolute values of relative deviations are≤4.2%.The method developed and described herein has been successfully employed in determining the trace Co2+in actual zinc electrolyte. 展开更多
关键词 catalytic adsorptive voltammetry highly selective masking Co^2+determination zinc electrolyte
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The analysis of distributed photovoltaic access system schemes
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作者 Yuting Pan Yuchen Chen +1 位作者 Zhiqiang Yuan Bo Liu 《International English Education Research》 2014年第12期70-73,共4页
As the share of photovoltaic power generation in power system has increased year by year, the optimization choice of access system schemes become one of the first and most important problems in grid before admitting p... As the share of photovoltaic power generation in power system has increased year by year, the optimization choice of access system schemes become one of the first and most important problems in grid before admitting photovoltaic power generation. Therefore, this article takes a proposed distributed photovoltaic as an example to research and analyze two kinds of high density multiple access points distributed photovoltaic access system schemes. The emphasis is making a comprehensive comparison and selection among the aspect of active power loss and economic benefit, etc. In the premise of ensuring the normal power generation of the photovoltaic system, it puts forward the recommended scheme that can help to spontaneous self-consumption, elimination on the spot, effectively decrease network loss and economic benefit. 展开更多
关键词 Distributed photovoltaic power generation Access scheme Active power loss Economic benefit
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