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Search Results: 1 - 10 of 484325 matches for " <br>李永纲 "
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Solid-Liquid Suspension in a Vertical Three-impeller Stirred Tank
立式圆槽内多轴搅拌器固—液悬浮性能

LI Yong-gang,HUANG Xiong-bin,<br>,黄雄斌
过程工程学报 , 2012,
Abstract: In order to improve the related efficiency in a storage tank, the solid-liquid suspension by three CBY III impellers 0.174 m diameter (D)] was studied. The three CBY III impellers were symmetrically fixed in a stirred tank with the diameter (T) of 2 m and height of 0.8 m. The optimum installing location and height of agitators were determined by analyzing the deposition area and just-suspension blade tip speed for glass beads of average 100 μm. The results show that the minimum just-suspension speed appears at 0.285R (R, the radius of tank, m) away from the tank wall, and the liquid level of 0.3T is superior to the situations of 0.2T and 0.25T, meanwhile the liquid level between 0.2T and 0.3T has only weak influence on power consumption. The power consumption of vertical three-impeller stirred tank is 2.8 times as that of standard stirred tank (single vertical agitator), but a vast of manufacturing cost can be saved. Compared with the three side-entering agitators, the vertical three-impeller agitation can save 20% of the energy when solids have 95% suspension, and installation and maintenance are very convenient and concise. It can be concluded that the vertical three-impeller agitation has an extensive application prospect in industrial storage tanks.
Analysis of 43 pesticide residues in vegetables using solid-phase extraction and gas chromatography-triple quadrupole mass spectrometry
固相萃取-三重串联四极杆气相色谱/质谱联用分析蔬菜中43种农药残留留

SHI Jiawei,LI Jige,WANG Yufei,ZHAO Yonggang,<br>施家威,继革,王玉飞,
色谱 , 2010,
Abstract: A method for the simultaneous analysis of 43 pesticide residues in vegetables by gas chromatography coupled with triple quadrupole mass spectrometry (GC-QqQ-MS/MS) was developed and validated. The samples were extracted with acetonitrile, and then purified by solid-phase extraction (SPE). The detection of 43 pesticides was carried out by GC-QqQ-MS/MS in the multi-reaction monitoring (MRM) mode using external standard method. The overall recoveries determined at three spiked levels of 10, 80 and 100 μg/kg were 62.2%~170.0%, which in the recoveries of 36 pesticides were 70.0%~120.0%. The relative standard deviations (RSDs) were less than 18%. The limits of quantification (S/N≥10) were 0.3~4.4 μg/kg. The method possesses low background and high sensitivity. It can be applied to the routine analysis of the 43 pesticides in vegetables.
Source Apportionment of Polycyclic Aromatic Hydrocarbons in the Topsoil of Tianjin
天津表层土壤中多环芳烃的主要来源

DUAN Yong-hong,TAO Shu,WANG Xue-jun,LI Ben-gang,ZHU Li-zhong,LUO Yong-ming,<br>段,陶澍,王学军,,朱利中,
环境科学 , 2006,
Abstract: The sources of PAHs in the topsoil were apportioned using principal component analysis with multiple linear regression.Three sub-regions with significant differences in PAH levels and profiles were investigated individually.The results indicated that coal combustion and coking production were the dominate PAH source for the entire Tianjin,particularly for Tanggu-Hangu region with the highest PAH level,to which 79% of PAHs came from coal combustion and coking industry and 21% was from vehicles.For the city center and outskirts,vehicles and coal burning contributed 35% each,while incineration provided 21% of the total. Sources of PAHs in rural soil with relatively low level of PAHs were more diverse.In addition to coal,vehicles,and coking,straw burning added 11% to the total.The results based on the source apportionment were compared with those from emission modeling.
立式圆槽内多轴搅拌器固-液悬浮性能
,黄雄斌
过程工程学报 , 2012,
Abstract: 在直径(T)为2m、高(H)为0.8m的圆形搅拌槽内,采用三桨搅拌,桨型为CBYIII(桨径D=0.174m),3个桨在槽内均匀分布,通过对临界悬浮叶端线速度、沉积面积的分析,研究了搅拌桨槽内最优安装位置.结果表明,最优径向安装位置为距壁面0.285R(R为圆形搅拌槽半径,m)处;液位为0.3T时的搅拌效果优于0.2T和0.25T;但液位在一定(0.2T~0.3T)范围内对功率的影响微小.对比分析实验结果与文献数据可知,达到相同完全悬浮状态,立式多轴搅拌的功率消耗为单轴情况下(D=0.731m)的2.8倍,但立式多轴搅拌器的制造成本更低;与侧伸式搅拌相比,5%沉积面积时立式多轴搅拌节省20%能耗,且安装维护更简便,在大型储罐中具有广泛的工业应用前景.
Microbial biomass and paddy soil enzyme activity in organic and conventional farming systems
有机栽培和常规栽培水稻体系土壤酶及微生物量的比较研究

WANG Yan-Jun,ZONG Liang-Gang,LI Rui,WEI Zeng-Gui,YANG Yong-Gang,XIAO Xing-Ji,<br>王延军,宗良,,魏增贵,,肖兴基
中国生态农业学报 , 2008,
Abstract: 本研究探讨了有机栽培与常规栽培体系下水稻土微生物量及脲酶、酸性磷酸酶和过氧化氢酶的动态变化过程,以及有机栽培体系不同肥料调控措施对上述指标的影响.结果表明:与常规栽培水稻体系相比,有机栽培水稻有利于土壤微生物的生长和繁衍;水稻生长不同时期有机栽培方式的土壤微生物生物量碳、脲酶、酸性磷酸酶和过氧化氢酶活性均高于常规栽培体系.就水稻全生育期而言,土壤微生物生物量碳高于常规栽培7.3%~9.1%;脲酶、酸性磷酸酶和过氧化氢酶活性分别高于常规栽培7.3%~14.5%、5.2%~6.5%和12.5%~29.2%;有机水稻栽培体系下配施生态肥,在有机肥施用量减半时,土壤微生物生物量碳含量及土壤脲酶、酸性磷酸酶和过氧化氢酶活性较单施有机肥平均分别提高1.6%、6.8%、1.3%和14.8%,在水稻生长前期和中期该增加作用尤为显著.
Spatial Pattern and Component Structure of Forests in Guizhou
贵州森林的空间格局及组成结构

YAO Yonghui,ZHANG Baiping,ZHOU Chenghu,LUO Yang,ZHU Jun,CEN Gang,LI Baolin,CHEN Xiaodong,<br>姚,张百平,周成虎,罗扬,朱军,,宝林
地理学报 , 2003,
Abstract: ArcGIS processing of remote sensed and investigated data of Guizhou forest resources in 2000 gives rise to forest resource distribution map, forest age class structure, and the distribution map of forest canopy. Ana lysis of these data shows that: (1) though there are multiple types of fores t resources, forest coverage is low (only 25.27%, excluding sparse woodl and, shrub and underage-forest);(2) the geographical distribution of fo rests is quite uneven, mainly in the southeast of the province and i n Zunyi prefecture; (3) the zonal evergreen broad-leaved forests have b een seriously destroyed, and the forest has obvious secondary features, with coniferous forest and shrubbery accounting for the greatest proportion of Guizhou forest; (4) the area of timber-forest is much larger than th at of shelter-forest and economic forest; (5) young-and-middle age fores ts account for greater proportion than near-and-over matured forest; an d (6) the forest of Guizhou is not enough to effectively protect the e nvironment of karst mountain areas of the province.
Analysis of seven compounds in mainstream cigarette smoke by ultra performance liquid chromatography using a β-cyclodextrin mobile phase additive
超高效液相色谱β-环糊精流动相添加剂法分析卷烟主流烟气中7种酚类化合物

LI Zhonghao,TANG Gangling,PANG Yongqiang,JIANG Xingyi,CHEN Zaigen,HU Qingyuan,<br>中皓,,,姜兴益,陈再根,胡清源
色谱 , 2010,
Abstract: A rapid method for the analysis of hydroquinone, resorcinol, catechol, phenol, p-cresol, m-cresol, and o-cresol in mainstream cigarette smoke by ultra performance liquid chromatography (UPLC) using a β-cyclodextrin (β-CD) mobile phase additive was developed. The seven major phenolic compounds in mainstream smoke were collected with YC/T 255-2008 standard method. The extract was filtrated with 0.22 μm filtration film and then subjected to UPLC analysis. The separation was performed on an ACQUITY UPLC BEH Shield RP18 column, and the mobile phase with 4 g/L β-CD additive was used. The fluorescence detection condition was optimized. The analysis time was 10 min for one sample. Comparing with the high performance liquid chromatography (HPLC) methods published, the p-cresol and m-cresol were completely separated. In addition, the effect of β-CD on fluorescence enhancement for seven major phenolic compounds was significant. The linearity were good between the peak area and the concentration in the linear ranges of seven phenolic compounds, and the correlation coefficients were greater than 0.9999. The limits of detection of the method were 4-14 ng/cig, and the recoveries were 95.5%-103.5% with relative standard deviations (RSDs) less than 4%.
Professional Journals Should Combine Its Special Characteristics with Five Elements
行业期刊应做好“五个结合”

LI QiGang,<br>
中国科技期刊研究 , 2006,
Abstract: 在新的形势下,行业期刊必须树立新的办刊理念,不断提升办刊质量和水平,扩大发行量。为此,应做到行业性与期刊特色相结合、专业性与时代性相结合、指导性与可读性相结合、办刊与开展活动相结合、质量与发行量相结合。
氨基功能化纳米Fe3O4磁性高分子吸附剂对废水中Cr(VI)的吸附研究
,沈昊宇,,夏清华
化学学报 , 2009,
Abstract: 采用分散聚合法通过共聚、开环反应,对纳米Fe3O4进行表面功能化修饰,得到富含NH2官能团的纳米磁性高分子复合材料.通过透射电镜(TEM)、振动样品磁强计(VSM)、热重差热分析(TGA)、X射线衍射(XRD)、红外光谱(IR)等对其进行表征,着重研究了其作为吸附剂对Cr(VI)的吸附性能.结果表明该吸附剂对Cr(VI)的吸附能在10min内达到平衡;废水溶液pH值能显著影响吸附剂对Cr(VI)的吸附效果,pH为2.5时效果最佳.废水中Cr(VI)的初始浓度、吸附时间、温度等因素对吸附效果均有不同程度的影响.结合相应pH值下Cr(VI)的形态分布,探讨了这种新型材料对Cr(VI)的吸附机理.结果表明其吸附机理及吸附容量与废水中Cr(VI)的离子形式有关;吸附过程以离子交换与静电引力为主.等温吸附数据符合Langmuir模型,T=308K,pH=2.5,V=40mL时,吸附剂的饱和吸附容量qm=25.58mg/g.吸附为吸热过程,焓变ΔH=8.64kJ/mol.
采用密闭取心和改装静力触探仪勘察第四系有害气体
,,余雷
煤田地质与勘探 , 2009,
Abstract: 长江三角洲一些城市的地铁工程勘察过程中发现了具有较高压力的第四系浅层天然气。鉴于第四系浅层天然气对地铁建设工程的危害,针对杭州地铁遇到的第四系有害气体的特点,采用横波地震法确定了有害气体的分布范围;采用密闭取心法查明了有害气体的赋存规律;采用改装型静力触探仪法查明了有害气体的成分、气源层、储气层、埋藏深度和压力。工程勘察结果表明,达到了杭州地铁工程第四系有害气体勘察的目的。
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