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离心式油菜精量排种器型孔结构设计与试验 被引量:26
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作者 曹秀英 廖庆喜 +1 位作者 丛锦玲 廖宜涛 《农业机械学报》 EI CAS CSCD 北大核心 2014年第S1期40-46,共7页
针对传统机械离心式油菜排种器型孔易出现堵塞导致后续断条的问题,进行了离心式油菜精量排种器型孔结构的研究,分析了型孔囊取1、2、3粒油菜种子的临界直径;结合EDEM种子运动轨迹的仿真分析得到了型孔囊取1、2、3粒种子的临界值分别为2.... 针对传统机械离心式油菜排种器型孔易出现堵塞导致后续断条的问题,进行了离心式油菜精量排种器型孔结构的研究,分析了型孔囊取1、2、3粒油菜种子的临界直径;结合EDEM种子运动轨迹的仿真分析得到了型孔囊取1、2、3粒种子的临界值分别为2.6、3.5、3.8 mm;同时试验研究了型孔直径、转速与排种性能关系,进行了型孔堵塞统计试验。结果表明:改进后型孔直径取3.8 mm时,其总排量稳定性变异系数不大于14.8%,各行排量一致性变异系数不大于16.4%,型孔无堵塞现象。 展开更多
关键词 离心式排种器 油菜 堵塞 型孔结构
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油菜高速机械离心式集排器设计与试验 被引量:1
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作者 廖庆喜 沈文惠 +3 位作者 王磊 霍佳琪 罗湛程 廖宜涛 《农业机械学报》 EI CAS CSCD 北大核心 2024年第7期154-167,共14页
针对传统油菜机械离心式集排器高速作业时供种及投种能力不足,导致排种量与作业速度不匹配、排种性能不稳定等问题,设计了一种被动式供种、“圆孔+渐变孔柱”组合式型孔投种的油菜高速机械离心式集排器。构建了供种、投种过程中的力学模... 针对传统油菜机械离心式集排器高速作业时供种及投种能力不足,导致排种量与作业速度不匹配、排种性能不稳定等问题,设计了一种被动式供种、“圆孔+渐变孔柱”组合式型孔投种的油菜高速机械离心式集排器。构建了供种、投种过程中的力学模型,分析确定了影响排种性能的关键结构参数;利用EDEM离散元仿真开展了供种调节高度对供种速率调节量影响的试验,结果表明当供种调节高度为3~8 mm时,供种速率在64.95~357.54 g/min范围内可调;采用两因素三水平正交试验分析了限种套筒下摆高度及倾角对初始种量、临界转速及环状种层最大高度的影响。通过台架试验确定了较优限种套筒结构参数,结合高速摄影对比了5种型孔结构下动锥体转速与排种量关系,确定最优型孔结构为“圆孔+渐变孔柱”组合式型孔。较优参数组合集排器排种性能验证试验结果表明:当转速为115~205 r/min时,排种速率为60.96~355.76 g/min,油菜各行排量一致性变异系数均低于5.2%,总排量稳定性变异系数均低于1.3%,破损率低于0.5%,满足作业速度6~12 km/h时的排种量要求。田间试验结果表明,当机组作业速度为7.89、11.98 km/h时,油菜各行植株均匀性变异系数低于11%,种植密度为43~58株/m^(2),满足油菜精量播种要求。 展开更多
关键词 油菜 高速机械离心式集排器 型孔结构 离散元仿真
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正负气压组合油菜精量排种器锥孔盘排种性能 被引量:15
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作者 高丽萍 施彬彬 +3 位作者 廖庆喜 张百祥 郑娟 廖宜涛 《农业工程学报》 EI CAS CSCD 北大核心 2022年第6期22-33,共12页
为进一步提升正负气压组合式油菜精量排种器性能,该研究提出了一种可增加种群扰动、降低被吸附种子运移阻力的圆锥型孔排种盘。通过理论分析和离散元仿真试验阐明倒角截顶圆锥孔排种盘排种性能提升机理,并通过台架试验对排种性能提升效... 为进一步提升正负气压组合式油菜精量排种器性能,该研究提出了一种可增加种群扰动、降低被吸附种子运移阻力的圆锥型孔排种盘。通过理论分析和离散元仿真试验阐明倒角截顶圆锥孔排种盘排种性能提升机理,并通过台架试验对排种性能提升效果进行了验证。理论分析表明,在排种盘上采用圆周密布的圆锥型孔,排种盘型孔临近吸种区域种群横向扰动增大,型孔上被吸附种子随排种盘运移时的切向阻力降低,利于提高充种成功率和携种稳定性。离散元仿真分析表明,相同型孔数条件下倒角截顶圆锥孔盘较圆直孔盘在充种室种群平均速度增大66.72%;在型孔附近临近吸种区种子切向运移速度提高90.45%,轴向运移速度增加83.90%,径向运移速度提高165.60%,吸附在型孔上的种子运动阻力下降35.60%。台架试验表明,在工作负压800~4800 Pa、转速10~50 r/min条件下,倒角截顶圆锥孔排种盘较圆直孔排种盘单粒排种合格指数提高5.49%、重播指数及漏播指数分别降低68.62%和3.79%,在卸种正压200 Pa、工作负压2100 Pa、转速25 r/min条件下,其合格指数、重播指数、漏播指数最高可达98.13%、1.25%和0.62%。倒角截顶圆锥孔排种盘在不增加附属搅种和充种装置的基础上,可有效提高单粒排种性能,降低排种器重播指数和漏播指数,提升排种器作业性能,研究结果可为正负气压组合式油菜精量排种器结构优化提供参考。 展开更多
关键词 设计 试验 油菜 精量排种器 正负气压组合 排种性能 圆锥型孔结构
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用于RFCC催化剂的Y型分子筛的研究进展 被引量:1
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作者 孙志国 高雄厚 +3 位作者 马建泰 张莉 刘宏海 王宝杰 《现代化工》 CAS CSCD 北大核心 2016年第1期45-48,共4页
指出了目前重油催化裂化(RFCC)催化剂研究的核心在于减少重油分子在Y型分子筛中的扩散限制;研究方向主要集中在制备具有介-微孔结构的Y型分子筛和制备小晶粒Y型分子筛。分别介绍了介-微孔结构Y型分子筛和小晶粒Y型分子筛的优势、存在的... 指出了目前重油催化裂化(RFCC)催化剂研究的核心在于减少重油分子在Y型分子筛中的扩散限制;研究方向主要集中在制备具有介-微孔结构的Y型分子筛和制备小晶粒Y型分子筛。分别介绍了介-微孔结构Y型分子筛和小晶粒Y型分子筛的优势、存在的问题以及制备的方法。最后提出了制备用于RFCC催化剂的新型Y型分子筛的发展趋势。 展开更多
关键词 重油 催化裂化 扩散限制 介-微结构Y分子筛 小晶粒Y分子筛
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Numerical simulation of rock pore-throat structure effects on NMR T_2 distribution 被引量:4
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作者 王克文 李宁 《Applied Geophysics》 SCIE CSCD 2008年第2期86-91,共6页
We built a three-dimensional irregular network model which can adequately describe reservoir rock pore-throat structures. We carried out numerical simulations to study the NMR T2 distribution of water-saturated rocks.... We built a three-dimensional irregular network model which can adequately describe reservoir rock pore-throat structures. We carried out numerical simulations to study the NMR T2 distribution of water-saturated rocks. The results indicate that there is a good correlation between T2 distribution and the pore radius frequency histogram. The total T2 distribution can be partitioned into pore body and pore throat parts. The effect of parameters including throat radius, pore-throat ratio, and coordination number of the micro- pore structure on the T2 distribution can be evaluated individually. The result indicates that: 1 ) with the increase of the pore throat radius, the T2 distribution moves toward longer relaxation times and its peak intensity increases; 2) with the increase of the pore-throat ratio, the T2 distribution moves towards longer T2 with the peak intensity increasing and the overlap between pore body T2 and pore throat T2 decreasing; 3) With the increase of connectivity, the short T2 component increases and peak signal intensity decreases slightly. 展开更多
关键词 Network model NMR T2 distribution Pore structure Microstructure modeling
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Mathematical Model of Gas Permeation Through PTFE Porous Membrane and the Effect of Membrane Pore Structure 被引量:2
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作者 张秀莉 张卫东 +3 位作者 郝新敏 张慧峰 张泽廷 张建春 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2003年第4期383-387,共5页
Membrane-based separation processes are new technology combined membrane separation with conventional separation. Hydrophobic porous membranes are often used in these processes. The structure of hydrophobic porous mem... Membrane-based separation processes are new technology combined membrane separation with conventional separation. Hydrophobic porous membranes are often used in these processes. The structure of hydrophobic porous membrane has significant effect on mass transfer process. The permeabilities of five kinds of gas, He, N2, O2, CO2 and water vapor, across six polytetrafluoroethylene(PTFE) flat membranes were tested experimentally. Results indicated that the greater the membrane mean pore size and the wider the pore size distribution are, the higher the gas permeability. A gas permeation model, including the effects of membrane structure parameter and gas properties, was established. A comprehensive characteristic parameter (including porosity, thickness and tortuosity) was found more effective to express the influence of membrane structure in gas permeation process. The predicted permeation coefficients were in good agreement with experimental data. 展开更多
关键词 porous membrane gas permeability mathematical model
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Hydrothermal Synthesis and Properties of Y-zeolite-containing Composite Material with Micro/mesoporous Structure 被引量:3
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作者 Zhou Jihong Min Enze +3 位作者 Shu Xingtian Zong Baoning Yang Haiying Luo Yibin (State Key Laboratory of Catalytic Material and Reaction Engineering,Research Institute of Petroleum Processing,SINOPEC,Beijing 100083) 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2010年第1期1-4,共4页
A Y-zeolite-containing composite material with micro/mesoporous structure had been synthesized from kaolin by means of the in-situ crystallization method. The obtained samples were investigated by XRD and BET methods.... A Y-zeolite-containing composite material with micro/mesoporous structure had been synthesized from kaolin by means of the in-situ crystallization method. The obtained samples were investigated by XRD and BET methods. Evaluation of catalytic activity of both the commercial Y-zeolite and the novel Y-zeolite-containing composite material was carried out in the pulse micro-chromatography platform with two probe molecules of different molecular sizes: VGO feedstock and 1,3,5 tri-isopropyl benzene. It was found that the Y-zeolite-containing composite material was richer in external surface and meso-/macro-pores; the Y-zeolite-containing composite material demonstrated a smaller rate of deactivation compared to the commercial Y-zeolite. 展开更多
关键词 FAUJASITE hydrothermal synthesis Y-zeolite-containing composite material micro/mesoporous structure kaolin
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Development and application of an efficient gas extraction model for low-rank high-gas coal beds 被引量:28
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作者 Baiquan Lin 《International Journal of Coal Science & Technology》 EI 2015年第1期76-83,共8页
To promote gas extraction in low-rank high-gas coal beds, the pore structure characteristics of the coal and their effect on gas desorption were studied. The results show that micropores are relatively rare in low-ran... To promote gas extraction in low-rank high-gas coal beds, the pore structure characteristics of the coal and their effect on gas desorption were studied. The results show that micropores are relatively rare in low-rank coal; mesopores are usually semi-open and inkpot-shaped whereas macropores are usually slit-shaped. Gas desorption is relatively easy at high- pressure stages, whereas it is difficult at low-pressure stages because of the 'bottleneck effect' of the semi-open inkpot-shaped mesopores. A 'two-three-two' gas extraction model was established following experimental analysis and engineering practice applied in the Binchang mining area. In this model, gas extraction is divided into three periods: a planning period, a transitional period and a production period. In each period, surface extraction and underground extraction are performed simultaneously, and pressure-relief extraction and conventional extraction are coupled to each other. After applying this model, the gas extraction rate rose to 78.8 %. 展开更多
关键词 Low-rank coal Pore structure Gas extraction Inkpot-shaped pore
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Study on water saturation computation models in complex pore volcanic reservoir 被引量:1
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作者 BIAN Huiyuan SHI Danhong +2 位作者 HAN Shuang PAN Baozhi ZHANG Lihua 《Global Geology》 2012年第1期53-57,共5页
Determination of water saturation is important for reservoir evaluation. When complex pore structures such as fracture and cavity are present in reservoir, Archie equation is no longer suitable. According to different... Determination of water saturation is important for reservoir evaluation. When complex pore structures such as fracture and cavity are present in reservoir, Archie equation is no longer suitable. According to different models of pore structure division, the authors studied water saturation conlputation models. The results show that dual porosity system is divided into four models. The first model is based on dual laterolog, the second is Dual Porosity I , the third is Dual Porosity Ⅱ , and the last one is based on the conductive pore. Besides, the triple porosity system is triple porosity model. Compute water saturation was using all the above five models in volcanic reservoir in Songnan gas field. The triple porosity system is the most suitable model for water saturation computation in complex pore structure volcanic reservoir. 展开更多
关键词 water saturation triple porosity model dual porosity model complex pore structure
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Model experiment of rock blasting with single borehole and double free-surface 被引量:5
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作者 TIAN Jian-sheng QU Fan-fei 《Mining Science and Technology》 EI CAS 2009年第3期395-398,404,共5页
In order to improve the quality of laneways and tunnel excavation by drilling and blasting and by making effective use of explosive energy, a model experiment of rock blasting with a single borehole and a double free-... In order to improve the quality of laneways and tunnel excavation by drilling and blasting and by making effective use of explosive energy, a model experiment of rock blasting with a single borehole and a double free-surface was performed with the objective of studying the effect of parameters such as charge structure, free-surface and rock compressive strength on rock blasting.The model experiments indicate that:1) the smaller the rock compressive strength and density, the more distinctive the cavity expanding action by blasting;2) the powder factor in an air-decoupling charge structure is larger than that in a coupling charge structure, i.e., the explosive energy in an air-decoupling charge structure transferred to the rocks is less than that in a coupling charge structure;3) a free-surface improves the utilizations of explosive energy;4) an air-decoupling charge structure helps to maintain the integrity and stability of wall rock in controlled perimeter blasting, such as in roadways and tunnel excavation by drilling and blasting. 展开更多
关键词 model experiment single borehole cylindrical charge air-decoupling charge structure free surface
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Synthesis and structural characterization of macroporous bioactive glass 被引量:1
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作者 周智华 阮建明 +2 位作者 邹俭鹏 周忠诚 申雄军 《Journal of Central South University of Technology》 EI 2007年第3期301-304,共4页
Porous sol-gel glass of CaO-SiO2-P2O5 system with macropores larger than 100 μm was prepared by adding stearic acid as pore former when the sintering was carried out at 700 ℃ for 3h.The sol-gel porous glass shows an... Porous sol-gel glass of CaO-SiO2-P2O5 system with macropores larger than 100 μm was prepared by adding stearic acid as pore former when the sintering was carried out at 700 ℃ for 3h.The sol-gel porous glass shows an amorphous structure. The diameter of the pore created by pore former varies from 100 to 300 μm, and macroporous glass has a narrow and small pore size distribution in mesoporous scale. The porosity and pore size of macroporous bioactive glass can be controlled. 展开更多
关键词 macroporous glass sol-gel method SYNTHESIS structural characterization
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Spatial Structure Characteristics Detecting of Landform based on Improved 3D Lacunarity Model 被引量:4
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作者 TAO Yang TANG Guo'an Josef STROBL 《Chinese Geographical Science》 SCIE CSCD 2012年第1期88-96,共9页
The spatial structure characteristics of landform are the foundation of geomorphologic classification and recognition.This paper proposed a new method on quantifying spatial structure characteristics of terrain surfac... The spatial structure characteristics of landform are the foundation of geomorphologic classification and recognition.This paper proposed a new method on quantifying spatial structure characteristics of terrain surface based on improved 3D Lacunarity model.Lacunarity curve and its numerical integration are used in this model to improve traditional classification result that different morphological types may share the close value of indexes based on global statistical analysis.Experiments at four test areas with different landform types show that improved 3D Lacunarity model can effectively distinguish different morphological types per texture analysis.Higher sensitivity in distinguishing the tiny differences of texture characteristics of terrain surface shows that the quantification method by 3D Lacu-narity model and its numerical integration presented in this paper could contribute to improving the accuracy of land-form classifications and relative studies. 展开更多
关键词 digital elevation model (DEM) 3D Lacunarity model spatial pattern terrain texture LANDFORM
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Study on Permeability of 2.5D Woven Reinforcement Materials with Fractal Theory
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作者 钱坤 李鸿顺 +1 位作者 曹海建 朱苏康 《Journal of Donghua University(English Edition)》 EI CAS 2009年第6期592-597,共6页
Permeability is one of the key issues in the design of molds and in the molding process for composite manufacture. As a disordered fibrous assembly, 2.5- dimension (2.5 D) woven reinforcement materials have complex ... Permeability is one of the key issues in the design of molds and in the molding process for composite manufacture. As a disordered fibrous assembly, 2.5- dimension (2.5 D) woven reinforcement materials have complex structure. It poses a challenge to the study of pore structure and the establishment of the theoretical permeability model. Toward addressing this problem, a powerful tool called fractal theory emerged. According to the analysis of 2.5 D woven reinforcement material stmcture using fractal theory, it is found that the structure has an obvious fractal character. Therefore, a permeability fractal model of 2.5D woven reinforcement material was established by cormbining the Hagen-Poiseulle equation with Darcy law according to the capillary vessel fractal model in this paper. The permeability was expressed as a function of the fractal dimension and microstructure parameter of the porous media in this model. The theoretical model is verified by experimental tests and the measurement data are in good agreement with the results obtained from the fractal medel . 展开更多
关键词 2.5-dimension PERMEABILITY reinforcement materials fractal geometry fractal model
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Behavior of phenol adsorption on thermal modified activated carbon 被引量:12
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作者 Dengfeng Zhang Peili Huo Wei Liu 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2016年第4期446-452,共7页
Adsorption process is acknowledged as an effective option for phenolic wastewater treatment. In this work, the activated carbon (AC) samples after thermal modification were prepared by using muffle furnace. The phen... Adsorption process is acknowledged as an effective option for phenolic wastewater treatment. In this work, the activated carbon (AC) samples after thermal modification were prepared by using muffle furnace. The phenol ad- sorption kinetics and equilibrium measurements were carried out under static conditions at temperature ranging from 25 to 55 ~C. The test results show that the thermal modification can enhance phenol adsorption on AC samples. The porous structure and surface chemistry analyses indicate that the decay in pore morphology and decrease of total oxygen-containing functional groups are found for the thermal modified AC samples. Thus, it can be further inferred that the decrease of total oxygen-containing functional groups on the modified AC sam- ples is the main reason for the enhanced phenol adsorption capacity. For both the raw sample and the optimum modified AC sample at 900 ~C, the pseudo-second order kinetics and Langmuir models are found to fit the exper- imental data very well. The maximum phenol adsorption capacity of the optimum modified AC sample can reach 144,93 mg.g ~ which is higher than that of the raw sample, i.e. 119.53 mg.g 1. Adsorption thermodynamics analysis confirms that the phenol adsorption on the optimum modified AC sample is an exothermic process and mainly via physical adsorption. 展开更多
关键词 AdsorbentsActivated carbonPhenolAdsorptionThermal modificationOxygen-containing functional groups
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简析水闸在施工期不容忽视的应力组合
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作者 白炳书 程伟 杨忠富 《浙江水利水电专科学校学报》 2003年第1期14-15,共2页
三孔闸站结合的箱型结构,在顶板刚浇筑完毕时,底板中间截面产生了超过按整体结构计算的负弯矩值.因此,在设计时应考虑这一不利荷截组合.
关键词 水闸 应力组合 结构 施工期 负弯矩 底板
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Study on application and numerical simulation of the airflow temperature distribution rule in drifting tunnel
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作者 李孝东 卢国斌 +1 位作者 张浪 周西华 《Journal of Coal Science & Engineering(China)》 2003年第1期90-94,共5页
According to the law of conservation in the state of turbulent flow, the differential equation describing the airflow temperature distribution in drifting tunnel is derived, By theoretical analysis and field measureme... According to the law of conservation in the state of turbulent flow, the differential equation describing the airflow temperature distribution in drifting tunnel is derived, By theoretical analysis and field measurement of the airflow and thermal process in mine, theoretical analysis and systematic flow are developed. By PHONENICS program, the numerical simulation is processed, and the changing rule of airflow temperature with various parameters in drifting tunnel is derived. The airflow temperature in drifting tunnel decreases as the airflow velocity increases in a way of negative power exponent, and elevates linearly as the temperature of the incoming airflow elevates. 展开更多
关键词 turbulent model porosity factor airflow flow field temperature field
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Acoustic-electrical properties and rock physics models for shale-oil formations:prediction of reservoir properties of interbedded sandstone and shale layers
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作者 Pang Meng-Qiang Ba Jing +2 位作者 Wu Chun-Fang Carcione José Maria Müller Tobias 《Applied Geophysics》 SCIE CSCD 2022年第4期485-502,603,共19页
In recent years,the Yanchang shale-oil formations of the Ordos Basin are rich in reserves with complex lithology and structure characteristics,low porosity and low permeability,and weak anomalies for oil and water dis... In recent years,the Yanchang shale-oil formations of the Ordos Basin are rich in reserves with complex lithology and structure characteristics,low porosity and low permeability,and weak anomalies for oil and water discriminations,have been the key targets of unconventional oil/gas resource exploration and development in the relevant areas.The joint acoustic-electrical(AE)properties can be used to interpret reservoir lithology,mineralogy,pore structure,and fluid saturation.To conduct tests of thin section analysis,X-ray diff raction,and ultrasonic and electrical experiments at diff erent pressures and saturation degrees,cores from the shale-oil formations in the Q area of the basin are collected.The variations in AE properties with respect to clay content,porosity,pressure(microfracture),and saturation are analyzed.The experimental results indicate that the rock physics behaviors of sandstones with diff erent clay contents vary significantly.The AE properties of clean sandstones are basically dependent on the microfractures(pressure),while for muddy sandstones,the clay content is an important factor affecting the responses.The target reservoir consists of interbedded sandstone and shale layers.The AE equivalent medium equations and the Gurevich theory are applied to establish the joint models for the diff erent lithologies and simulate the variations in AE properties with respect to fluid type,pore structure,and mineral components.The three-dimensional joint templates of clean and muddy sandstones,as well as shale,are developed based on the elastic and electrical attributes and then calibrated using the experimental and well-log data.The reservoir properties are estimated with the templates and validated by the log data.The results indicate that the joint templates based on lithology characteristics can eff ectively characterize the properties of interbedded sandstone and shale layers.Furthermore,the combined application of AE data provides more beneficial information for the assessment of rock properties,leading to precise estimates that conform with the actual formation conditions. 展开更多
关键词 shale-oil formations acoustic-electrical(AE)properties interbedded layers clay content pore structure rock physics model
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Modeling porous structure of oil-pressboard interface and its effect on electric field distribution
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作者 司马文霞 姜赤龙 +1 位作者 毛文奇 唐信 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第1期338-343,共6页
The oil-pressboard insulation is a typical composite insulation system widely used in the design and manufactory of large power apparatus. The implement of oil-pressboard insulation may lead to surface electrification... The oil-pressboard insulation is a typical composite insulation system widely used in the design and manufactory of large power apparatus. The implement of oil-pressboard insulation may lead to surface electrification and discharge at the interface under certain condition. It is of significant importance to take an insight into the phenomenon occurring at the interface. Through experiment, the pressboard is found as a porous material. The interface changes abruptly from bulk pressboard to the bulk oil as a result of the porous structure. A new model is proposed which divides the interface into bulk oil region, transition region, and bulk pressboard region. The width of the transition region is decided according to the microtome figure. The effective permittivity of the transition region is calculated using a new model based on fractal theory. The model is validated and compared with previous calculation model. The effect of the existence of transition region on the electric field distribution is discussed. 展开更多
关键词 oil-pressboard interface transition region effective permittivity fractal electric field distribution
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Porous carbon matrix-encapsulated MnO in situ derived from metalorganic frameworks as advanced anode materials for Li-ion capacitors 被引量:3
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作者 Sipeng Jiang Shilin Yun +3 位作者 Haijie Cao Zhiqiang Zhang Hongbin Feng Haichao Chen 《Science China Materials》 SCIE EI CAS CSCD 2022年第1期59-68,共10页
Conversion-type anode materials hold great potential for Li+storage applications owing to their high specific capacity,while large volume expansion and poor electrical conductivity limit their rate and cycling perform... Conversion-type anode materials hold great potential for Li+storage applications owing to their high specific capacity,while large volume expansion and poor electrical conductivity limit their rate and cycling performances.Herein,a bimetal ZnMn-based metal-organic framework(ZnMn-MOF)is engineered for in situ conversion of MnO-encapsulated porous carbon(MnO/PC)composite.The templating and activation effects of coordinated Zn endow the converted PC matrix with a highly porous structure.This enhances the compatibility of PC matrix with MnO particles,resulting in the full encapsulation of MnO particles in the PC matrix.More significantly,the PC matrix provides enough void space to buffer the volume change,which fully wraps the MnO without crack or fracture during repeated cycling.As a result,MnO/PC shows high charge storage capability,extraordinary rate performance,and long-term cycling stability at the same time.Thus MnO/PC exhibits high delithiation capacities of 768mA h g^(-1)at 0.1Ag^(-1)and 487mA h g^(-1)at a high rate of 0.7Ag^(-1),combined with an unattenuated cycling performance after 500 cycles at 0.3Ag^(-1).More significantly,MnO/PC demonstrates a well-matched performance with the capacitive activated carbon electrode in a Li-ion capacitor(LIC)full cell.LIC demonstrates a high specific energy of 153.6W h kg^(-1)at 210W kg^(-1),combined with a specific energy of 71.8W h kg^(-1)at a high specific power of 63.0kW kg^(-1). 展开更多
关键词 Li-ion capacitors MnO/porous carbon composites metal-organic frameworks derivant conversion-type anode materials
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A comparative study of the specific surface area and pore structure of different shales and their kerogens 被引量:26
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作者 CAO TaoTao SONG ZhiGuang +1 位作者 WANG SiBo XIA Jia 《Science China Earth Sciences》 SCIE EI CAS CSCD 2015年第4期510-522,共13页
The pore structures and controlling factors of several different Paleozoic shales from Southern China and their kerogens were studied using nitrogen adsorption and scanning electron microscopy methods. The results ind... The pore structures and controlling factors of several different Paleozoic shales from Southern China and their kerogens were studied using nitrogen adsorption and scanning electron microscopy methods. The results indicate that: 1) The specific surface area is 2.22-3.52 m2/g and has no correlation with the TOC content of the Permian Dalong Formation shales, nanopores are extremely undeveloped in the Dalong Formation kerogens, which have specific surface areas of 20.35-27.49 me/g; 2) the specific surface area of the Silurian Longmaxi Formation shales is in the range of 17.83-29.49 m2/g and is positively correlated with TOC content, the kerogens from the Longmaxi Formation have well-developed nanopores, with round or elliptical shapes, and the specific surface areas of these kerogens are as high as 279.84-300.3 m2/g; 3) for the Niutitang Formation shales, the specific surface area is 20.12-29.49 m2/grock and increases significantly with increasing TOC and smectite content. The Niuti- tang Formation kerogens develop a certain amount of nanopores with a specific surface area of 161.2 m2/g. Oil shale was also examined for comparison, and was found to have a specific surface area of 19.99 m2/g. Nanopores are rare in the Youganwo Formation kerogen, which has a specific surface area of only 5.54 m2/g, suggesting that the specific surface area of oil shale is due mainly to the presence of smectite and other clay minerals. The specific surface area and the number of pores present in shales are closely related to TOC, kerogen type and maturity, smectite content, and other factors. Low-maturity kerogen has very few nanopores and therefore has a very low specific surface area, whereas nanopores are abundant in mature to over- mature kerogen, leading to high specific surface areas. The Longmaxi Formation kerogen has more developed nanopores and a higher specific surface area than the Niutitang Formation kerogen, which may be due to differences in the kerogen type and maceral components. A high content of smectite may also contribute to shale surface area. The pore volume and specific sur- face area of low-maturity kerogens are mainly attributable to pores with diameters above 10 nm. By contrast, the pore volume of mature kerogens consists predominantly of pores with diameters above 10 nm with some contribution from about 4 nm diameter pores, while the specific surface area is due mainly to pores with diameters of less than 4 nm. Through a comparative study of the specific surface area and pore structure characteristics of different shales and their kerogens, we conclude that the Longmaxi Formation shales and Niutitang Formation shales have greater sorption capacities than the Dalong Formation shales. 展开更多
关键词 different Paleozoic shales KEROGEN specific surface area NANOPORE MATURITY kerogen type
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