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Experimental study of near-bed concentration and sediment verticalmixing parameter for vertical concentration distribution in the surfzone 预览
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作者 Yang Zhang Zhili Zou +1 位作者 Wushan Xue Dapeng Sun 《国际泥沙研究:英文版》 SCIE 2020年第1期27-41,共15页
Two formulae for the near-bed concentration(Ca)and the sediment vertical mixing parameter(m)are established based on a large scale wave flume experiment.The advantage of the new formulae is that the turbulent kinetic ... Two formulae for the near-bed concentration(Ca)and the sediment vertical mixing parameter(m)are established based on a large scale wave flume experiment.The advantage of the new formulae is that the turbulent kinetic energy induced by wave breaking can be taken into account;the formula for Ca is in terms of the near-bed,time-averaged turbulent kinetic energy,and the formula for m is in terms of depth-and time-averaged turbulent kinetic energy.A new expression for suspended sediment load also is established by depth integration of the vertical distribution of the suspended sediment concentration obtained on basis of the new formulae.Equation validation is done by comparing the predicted Ca and m to measurements for different types of waves(regular wave,wave group,and irregular wave),and good agreement is found.The advantages of the proposed formulae over previous formulae also are discussed. 展开更多
关键词 Near-bed concentration Sediment vertical mixing parameter Turbulent kinetic energy Surf zone Wave type
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Removing Iron Ions Contaminants from Groundwater Using Modified Nano-Hydroxyapatite by Nano Manganese Oxide 预览
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作者 Mohammed Abd-El-Aal Ahmed Ayash Tarek Ahmed Seaf Elnasr Madiha Hassan Soliman 《水资源与保护(英文)》 2019年第6期789-809,共21页
In this article, we study modified nano-hydroxyapatite (HAp) by nano manganese oxide (Mn3O4) as adsorbent material to remove iron ions from groundwater. Different parameters were studied to option optimum conditions o... In this article, we study modified nano-hydroxyapatite (HAp) by nano manganese oxide (Mn3O4) as adsorbent material to remove iron ions from groundwater. Different parameters were studied to option optimum conditions of removing such as contact time, pH, initial concentration, a dosage of adsorbent, agitation speed and temperature. Kinetics studies included first order (R2 = 0.915), pseudo-first order (R2 = 0.936), second order (R2 = 0.948), pseudo-second order (R2 = 0.995), Elovich equation model (R2 = 0.977), intraparticle diffusion (R2 = 0.946), Natarajan and Khalaf (R2 = 0.915) were carried out, the obtained results revealed that the pseudo-second order is the best to describe the adsorption process because the correlation coefficient is approaching one (R2 = 0.995). Adsorption isotherm was calculated by using Freundlich, Langmuir and Temkin constants, adsorption capacity from Langmuir model was 0.606 mg/g. Thermodynamic parameters (ΔG, ΔH = ?51 KJ/mol, and ΔS = ?142 (KJ/mol)) for the adsorption process were also calculated and discussed. 展开更多
关键词 GROUNDWATER Adsorption NANO Materials HYDROXYAPATITE Manganese Oxide Iron Ions Kinetic THERMODYNAMIC
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Mechanism of sea ice formation based on comprehensive observation data in Liaodong Bay,China 预览
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作者 SHI Yongfang YANG Yongzeng +2 位作者 TENG Yong SUN Meng YUN Shengjun 《海洋湖沼学报(英文)》 SCIE CAS CSCD 2019年第6期1846-1856,共11页
Sea ice disaster is one of the principal natural hazards that affect some coastal areas of China,and the formation of ice cover in a wave field has important characteristics.However,analysis of the mechanism in which ... Sea ice disaster is one of the principal natural hazards that affect some coastal areas of China,and the formation of ice cover in a wave field has important characteristics.However,analysis of the mechanism in which waves affect the thermodynamic process of sea ice is lacking,and the influence of waves is not taken into consideration in numerical models of sea ice,largely because of a lack of simultaneous observations of waves and sea ice.Using observational data of the sea ice cycle in the coastal waters of Liaodong Bay(China),we analyzed the characteristics of hydrology,meteorology,and sea ice thickness during the formation of sea ice,and explored the changes in the interrelationships among heat fluxes,waves,and sea ice under actual sea conditions.The results could provide a decision-making support as a reference to the establishment and improvement of China's early waming system to sea ice disasters,and the protection of ice drilling operations and production platform safety. 展开更多
关键词 wave SEA ICE wave-induced TURBULENCE KINETIC energy
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Multi-objective optimization of a flow straightener in a large capacity firefighting water cannon 预览
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作者 Qing-jiang Xiang Lin Xue +1 位作者 Kwang-Yong Kim Zhe-fu Shi 《水动力学研究与进展:英文版》 SCIE EI CSCD 2019年第1期137-144,共8页
In the present study,a multi-objective optimization of a flow straightener in a firefighting water cannon is performed by using the surrogate modeling and a hybrid multi-objective genetic algorithm to increase the jet... In the present study,a multi-objective optimization of a flow straightener in a firefighting water cannon is performed by using the surrogate modeling and a hybrid multi-objective genetic algorithm to increase the jet range of the water cannon.Based on analysis using the three-dimensional Reynolds-averaged Navier-Stokes equations,the optimization is carried with a surrogate model and the radial basis neural network.Three geometric design variables,i.e.,the lengt扎 the thickness of the blade,and the radius of the outer pipe of the flow straightener,are selected for the optimization.The pressure drop through the water can non and the area-averaged turbulent kinetic energy at the outlet of the water cannon,which are closely related to the jet range of the water cannon,are selected as the objective functions to be minimized.The design space is determined through a parametric study,and the Latin hypercube sampling method is used to select the design points in the design space.The Pareto-optimal solutions are obtained through the optimization.Five representative Pareto-optimal solutions are selected to study the trade-off between two objectives. 展开更多
关键词 FIREFIGHTING water cannon MULTI-OBJECTIVE optimization surrogate model TURBULENCE KINETIC energy hydraulic LOSS
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Fe(NO3)3改性活性炭吸附氨氮的性能研究 预览
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作者 贾彪 赵烨 +2 位作者 冯海宁 符向前 任芝军 《哈尔滨商业大学学报:自然科学版》 CAS 2019年第1期30-36,共7页
通过超声浸渍法对活性炭进行负载Fe(NO3)3改性,采用扫描电镜(SEM)、比表面积分析(BET)、质量滴定、红外光谱分析(FT-IR)和Boehm滴定等多种分析方法对未改性活性炭(AC)和改性活性炭(AC-Fe)进行表征,探讨了在不同条件下改性前后活性炭对... 通过超声浸渍法对活性炭进行负载Fe(NO3)3改性,采用扫描电镜(SEM)、比表面积分析(BET)、质量滴定、红外光谱分析(FT-IR)和Boehm滴定等多种分析方法对未改性活性炭(AC)和改性活性炭(AC-Fe)进行表征,探讨了在不同条件下改性前后活性炭对污水中氨氮的吸附能力和动力学特性.结果表明,经超声浸渍铁元素改性后,活性炭大孔和中孔的孔容积以及比表面积减小,平均孔径略有增大,表面含氧官能团种类基本没有变化.AC-Fe的内酯基、酚羟基及碱基分别增加了12.8%、13.3%、4.4%,羧基减少了28.6%,其等电点由5.8增大到8.2.当氨氮质量浓度为10mg/L,活性炭投加量20g/L,温度5℃时,AC-Fe对氨氮的吸附量为0.138mg/g,较AC对氨氮的吸附量提高了29.0%.Langmuir方程和Freundlich方程均能较好地描述改性前后活性炭对氨氮的等温吸附过程,吸附动力学数据符合准二级动力学方程. 展开更多
关键词 活性炭 改性 氨氮 吸附 动力学
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Preparation and property of CL-20/BAMO-THF energetic nanocomposites 预览
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作者 Teng Chen Yan Zhang +6 位作者 Shuang-feng Guo Liu-ming Zhao Wei Chen Ga-zi Hao Lei Xiao Xiang Ke Wei Jiang 《Defence Technology(防务技术)》 CAS CSCD 2019年第3期306-312,共7页
A sol-gel freezing-drying method was utilized to prepare energetic nanocomposites based on 2, 4, 6, 8,10, 12-hexanitro-2, 4, 6, 8, 10, 12-hexaazaisowurtzitane(CL-20) with 3, 3-Bis(azidomethyl) oxetanetetrahydrofuran c... A sol-gel freezing-drying method was utilized to prepare energetic nanocomposites based on 2, 4, 6, 8,10, 12-hexanitro-2, 4, 6, 8, 10, 12-hexaazaisowurtzitane(CL-20) with 3, 3-Bis(azidomethyl) oxetanetetrahydrofuran copolymer(BAMO-THF) as energetic gel matrix. Scanning electron microscopy(SEM),X-ray diffraction(XRD), Raman, Fourier-transform infrared spectroscopy(FT-IR) and differential thermal analyser(DTA) were utilized to characterize the structure and property of the resultant energetic nanocomposites. Compared with raw CL-20, the average particle sizes of CL-20 in CL-20/BAMO-THF energetic nanocomposites were decreased to nano scale and the morphologies of CL-20 were also changed from prismatic to spherical. FT-IR detection revealed that CL-20 particles were recrystallized in BAMO-THF gel matrix during the freezing-drying process. The thermal decomposition behaviors of the energetic nanocomposites were investigated as well. The thermolysis process of CL-20/BAMO-THF nanocomposites was enhanced and the activation energy was lower compared with that of raw CL-20,indicating that CL-20/BAMO-THF nanocomposites showed high thermolysis activity. The impact sensitivity tests indicated that CL-20/BAMO-THF energetic nanocomposites presented low sensitivity performance. 展开更多
关键词 CL-20/BAMO-THF NANOCOMPOSITES KINETIC THERMODYNAMIC IMPACT sensitivity
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New Strategy and Kinetic Energy Regeneration for the Developmen of China’s Urban Agglomeration 预览
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作者 Li Chenghua Huang Nan Yu Yanjia(译) 《当代社会科学(英文)》 2019年第1期98-112,共15页
The rapid development of modern urban agglomerations has reshaped the territory of China’s economic geography and reconstructed the spatial forms of Chinese cities and regions.Since the reform and opening-up,China’s... The rapid development of modern urban agglomerations has reshaped the territory of China’s economic geography and reconstructed the spatial forms of Chinese cities and regions.Since the reform and opening-up,China’s urban agglomerations have experienced three stages,i.e.spontaneous cultivation,rapid growth,and the super leading role of planning.The gian development area composed of super urban agglomerations is becoming an emerging geographic unit that improves the urban development quality promotes regional integration processes and participates in global industria competition and innovative resource allocations in China.While encountering challenges such as insufficient innovation kinetic energy and implementation difficulties of cross-regional coordination mechanisms,it has also ushered in new opportunities brought about by the shift of the global urban network system focus,the accelerated formation of high-speed rail urban belts,the rise of innovative geographic unit communities,etc.As entering the new era,centering on the high-quality development requirements of urbanization and urban agglomerations,China should establish a new mechanism for more effective coordinated regional development,build an urban pattern of coordinated development of large,medium and small cities and towns with urban agglomerations as the main body,comprehensively enhance the competitiveness of urban agglomerations and regions,and take a steady and innovation-driven road to modernization. 展开更多
关键词 urban AGGLOMERATION GIANT development area KINETIC energy REGENERATION MULTI-CENTER integration
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An energy efficiency evaluation method for parallel robots based on the kinetic energy change rate
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作者 LIU XinJun BI WeiYao XIE FuGui 《中国科学:技术科学英文版》 SCIE EI CAS CSCD 2019年第6期1035-1044,共10页
Benefit from the high payload-to-weight ratio, parallel robots are expected to have a high potential for energy savings. However,it is a challenging issue to evaluate the energy efficiency of parallel robots with a qu... Benefit from the high payload-to-weight ratio, parallel robots are expected to have a high potential for energy savings. However,it is a challenging issue to evaluate the energy efficiency of parallel robots with a quantitative method. Quantitative energy efficiency evaluation methods include energy efficiency evaluation models and indices which mathematically describe the relationship between energy consumers in models and design variables of robots, such as geometry, mass and inertia parameters.Considering the structural features of parallel robots, the chains and the end effectors are identified as two separated energy consumers. Besides, the chains in parallel robots are identified as a transmission system which transfers energy from drives to the end effectors. On this basis, an energy efficiency evaluation model considering the change rate of kinetic energy stored in chains is built. The kinetic energy change rate of chains is influenced by design variables of robots as well as motion of the end effector.In order to give a quantitative description of energy efficiency performance of parallel robots, indices considering arbitrary velocity vector of the end effector are proposed. The evaluation method is suitable for all kinds of parallel robots with various motion conditions. Furthermore, the method can be used to optimize machining parameters and guide the design of energyefficient machines. 展开更多
关键词 ENERGY EFFICIENCY evaluation PARALLEL ROBOTS KINETIC ENERGY power TRANSMISSION
A case study of a Kuroshio main path cut-off event and impacts on the South China Sea in fall-winter 2013–2014 预览
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作者 Quanan Zheng Chung-Ru Ho +1 位作者 Lingling Xie Mingming Li 《海洋学报:英文版》 SCIE CAS CSCD 2019年第4期12-19,共8页
This study examines a Kuroshio main path(KMP)cut-off event east of Taiwan Island occurred in fall-winter 2013–2014 and its impacts on the South China Sea(SCS)by analyzing satellite altimetry and mooring observations.... This study examines a Kuroshio main path(KMP)cut-off event east of Taiwan Island occurred in fall-winter 2013–2014 and its impacts on the South China Sea(SCS)by analyzing satellite altimetry and mooring observations.Satellite altimeter sea level anomaly(SLA)images reveal a complete process that a huge cyclonic eddy(CE)from the Pacific collided with the Kuroshio and the western boundary from 15 October 2013 to 15 January 2014.Mooring observations evidenced that the Kuroshio upper ocean volume transport was cut off more than 82%from 17×10^6 m^3/s in September to 3×10^6 m^3/s in November 2013.The KMP cut-off event caused the Kuroshio branching and intruding into the SCS and strengthened the eddy kinetic energy in the northern SCS west of the Luzon Strait.Using the total momentum as a dynamic criterion to determine the role of eddy collision with the Kuroshio reasonably explains the KMP cut-off event. 展开更多
关键词 KMP CUT-OFF EVENT EDDY kinetic energy dynamic criterion South China Sea
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五彩湾煤和吐鲁番煤热解动力学模型评估与应用 预览
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作者 魏利平 江国栋 +1 位作者 古玉宽 滕海鹏 《化工学报》 EI CAS CSCD 北大核心 2019年第A02期275-286,共12页
煤热解是煤热加工利用的基础反应,热解动力学模型有助于预测煤在热解过程中挥发分脱除规律,当前文献中已报道了多种热解动力学模型,厘清不同热解模型参数选择的差异,评估不同模型对煤种及热解反应适应性可为热解工艺设计提供参考。采用1... 煤热解是煤热加工利用的基础反应,热解动力学模型有助于预测煤在热解过程中挥发分脱除规律,当前文献中已报道了多种热解动力学模型,厘清不同热解模型参数选择的差异,评估不同模型对煤种及热解反应适应性可为热解工艺设计提供参考。采用13CNMR核磁共振测量了五彩湾煤和吐鲁番煤的碳化学结构,并使用热重法测量了不同加热速率下的两种低阶煤失重曲线,结合分段式单一速率扫描法、等转化率法和3段式高斯分布活化能模型(3-DAEM)分析热重实验数据。结果表明单一速率扫描法得出的动力学参数难以准确揭示热解反应机理;等转化率法可以较好地得出热解活化能及指前因子分布图;将等转化率方法获得的指前因子赋值给分布活化能模型,可以避免分布活化能模型指前因子选择的盲目性;3-DAEM模型仅需要一条TGA曲线便可获得适用于整个加热速率的动力学参数,其预测结果与实验数据吻合最好,且模拟得出的活化能分布图很好地反映了煤热解三个阶段特征。 展开更多
关键词 热解 热重分析 分布活化能 动力学 模型
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利用V2O5制备氮化钒铁的反应过程及动力学研究 预览
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作者 王斌 李冬 +3 位作者 杜金晶 朱军 刘漫博 王欢 《中南大学学报:自然科学版》 EI CAS CSCD 北大核心 2019年第6期1278-1283,共6页
采用TG-DSC技术对V2O5直接制备氮化钒铁的反应过程进行研究,并采用Coats-Redfern积分法对相关反应的动力学参数进行计算。研究结果表明:碳还原V2O5的反应在670℃左右开始显著发生,随温度升高,反应速度加快。在1000℃以上时,碳化反应开... 采用TG-DSC技术对V2O5直接制备氮化钒铁的反应过程进行研究,并采用Coats-Redfern积分法对相关反应的动力学参数进行计算。研究结果表明:碳还原V2O5的反应在670℃左右开始显著发生,随温度升高,反应速度加快。在1000℃以上时,碳化反应开始进行,在1200℃左右,氮化反应可以显著发生,试样中可检测到氮化产物。在1150~1350℃反应的活化能要比970~1100℃时的高,说明随着反应的进行,生成的碳化钒铁和氮化钒铁产物产生了一定的包覆作用,扩散过程阻碍了反应的进一步进行。高温还原氮化后的试样,碳、氮元素在四周分布密集,而在中间区域分布较少,这也印证了碳化产物和氮化产物存在着明显包覆作用的推论。 展开更多
关键词 氮化钒铁 V2O5 反应过程 动力学
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硫酸铵焙烧粉煤灰的熟料溶出动力学研究 预览
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作者 隋丽丽 付云鹏 +1 位作者 王莹 翟玉春 《矿产综合利用》 CAS 北大核心 2019年第1期147-151,共5页
对硫酸铵焙烧粉煤灰的熟料溶出过程进行了动力学研究,根据不同温度、不同搅拌强度、不同液固比中Al2O3的溶出率和反应时间的关系,计算该反应的表观活化能为19.93kJ/mol,熟料的溶出过程受通过固体产物层的内扩散控制,动力学方程为:1+2(1-... 对硫酸铵焙烧粉煤灰的熟料溶出过程进行了动力学研究,根据不同温度、不同搅拌强度、不同液固比中Al2O3的溶出率和反应时间的关系,计算该反应的表观活化能为19.93kJ/mol,熟料的溶出过程受通过固体产物层的内扩散控制,动力学方程为:1+2(1-x)-3(1-x)2/3=4.52exp{-19929/RT}·t。在液固比8:1,溶出温度为90℃,搅拌强度为300r/min,溶出时间70min的条件下,Al2O3的溶出率可达84%。 展开更多
关键词 粉煤灰 硫酸铵 氧化铝 熟料溶出 动力学
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核电厂人员闸门顶升机构动力学仿真分析
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作者 谢洪虎 马文勤 +1 位作者 张峰 杨锦春 《核动力工程》 EI CAS CSCD 北大核心 2019年第3期70-74,共5页
为确保核电厂人员闸门顶升机构结构设计的合理性,对其在密封门启闭过程中的运动特性进行分析研究。本研究借助动力学仿真分析软件(ADAMS)对人员闸门顶升机构可能产生的故障失效模式进行了仿真分析,主要包括顶升机构传动箱运动学分析和... 为确保核电厂人员闸门顶升机构结构设计的合理性,对其在密封门启闭过程中的运动特性进行分析研究。本研究借助动力学仿真分析软件(ADAMS)对人员闸门顶升机构可能产生的故障失效模式进行了仿真分析,主要包括顶升机构传动箱运动学分析和传动丝杠动力学分析。分析结果表明,顶升机构传动箱的安装初始位置是导致顶升高度不足的直接因素;通过设置传动箱的初始安装位置、丝杠转速和运行时间可确保顶升高度达到设计要求的60 mm;此外,通过对主要动作部件的受力模拟分析,得出丝杠在径向上承载力可忽略,不会造成丝杠径向断裂事故出现。 展开更多
关键词 人员闸门 顶升机构 丝杠 动力学 仿真分析
异养硝化细菌Acinetobacter junii NP1的同步脱氮除磷特性及动力学分析
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作者 杨垒 陈宁 +4 位作者 任勇翔 崔珅 汪旭晖 肖倩 郭淋凯 《环境科学》 EI CAS CSCD 北大核心 2019年第8期3713-3721,共9页
针对传统生物脱氮除磷过程存在工艺流程复杂、抗冲击负荷能力差、基建与运行费用高等问题,以具有高效脱氮除磷功能的异养硝化细菌Acinetobacter junii NP1为研究对象,开展其同步脱氮除磷性能、影响因子及动力学分析.结果表明,菌株NP1具... 针对传统生物脱氮除磷过程存在工艺流程复杂、抗冲击负荷能力差、基建与运行费用高等问题,以具有高效脱氮除磷功能的异养硝化细菌Acinetobacter junii NP1为研究对象,开展其同步脱氮除磷性能、影响因子及动力学分析.结果表明,菌株NP1具有高效的异养硝化能力,氨氮最大去除率达99. 12%,反应过程只有少量的硝化中间产物积累,并且能够耐受较高的氨氮负荷.菌株NP1同时具有良好的好氧反硝化特性,能够利用亚硝酸盐和硝酸盐进行生长代谢,最大去除率分别为91. 40%和95. 10%.此外,菌株NP1异养硝化过程还伴随着同步的聚磷作用,适当的氮磷比有利于氮磷的同步去除,当氮磷比为5∶1时,最大氨氮和磷酸盐去除率分别为99. 21%和88. 35%.菌株NP1生长特性符合Logistic模型(R^2> 0. 99),氮素和磷酸盐降解过程则与修饰的Compertz模型相匹配(R^2> 0. 99),拟合所得氮和磷酸盐最大转化速率Rm为:氨氮>硝氮>亚硝氮,迟滞时间t0为:硝氮>亚硝氮>氨氮.通过基质降解动力学以及氮磷去除率分析,最佳条件是碳源为琥珀酸钠、C/N=10、T=30℃以及r=160 r·min^-1. 展开更多
关键词 琼氏不动杆菌 动力学 异养硝化 好氧反硝化 同步脱氮除磷
Computational study of bubbly jets in stagnant water 预览
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作者 Yan-xu Wang Ze-gao Yin +1 位作者 Wenming Zhang David ZZhu 《水动力学研究与进展:英文版》 SCIE EI CSCD 2019年第5期1021-1033,共13页
The air-water bubbly jets in a stagnant water are numerically investigated by using a CFD software package with the realizable k-e turbulence model.The focus is on the jet evolutionary behaviors in terms of the gas vo... The air-water bubbly jets in a stagnant water are numerically investigated by using a CFD software package with the realizable k-e turbulence model.The focus is on the jet evolutionary behaviors in terms of the gas void fraction,the axial water velocity,the turbulent kinetic energy(TKE),the entrainment coefficient,and the momentum and buoyancy fluxes in a wide range of the bubbly jets(with the initial gas volume fractions ranging from 0 to 0.83).The computational results are found generally in good agreement with the experimental results reported in the literature.Both the gas void fraction and the axial water velocity follow the Gaussian distribution in the radial direction as expected,however a double-peak distribution is found for the TKE at some distance away from the nozzle.With the increase of the longitudinal distance,their peak values generally are decreased until reaching approximately their terminal values.The non-dimensional relations are revealed in both the radial and longitudinal directions.The potential core and the spreading rates of the bubbly jets are then investigated.The liquid volume flux of the bubbly jets is found to increase almost linearly along the centerline with an entrainment coefficient of 0.037-0.065.The momentum flux of the bubbly jets increases due to the buoyancy force,and the relative importance of the momentum and buoyancy fluxes is also discussed. 展开更多
关键词 Bubbly jet gas void fraction axial water velocity turbulent kinetic energy(TKE) FLUX
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矿物质对高碱煤显微组分热解特性的影响 预览
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作者 李首毅 林雄超 +3 位作者 鲁倍倍 王永刚 张登跃 周云辉 《化工进展》 EI CAS CSCD 北大核心 2019年第8期3650-3657,共8页
利用固定床热解炉和热重分析仪研究了沙尔湖煤显微组分的热解特性和产物产率,考察了酸洗处理对热解产物和动力学参数的影响。结果表明:经浮沉实验发现镜质组富集于S2(密度为1.4~1.5g/cm^3浮选煤样)中,惰质组富集于S3(密度为>1.5g/cm^... 利用固定床热解炉和热重分析仪研究了沙尔湖煤显微组分的热解特性和产物产率,考察了酸洗处理对热解产物和动力学参数的影响。结果表明:经浮沉实验发现镜质组富集于S2(密度为1.4~1.5g/cm^3浮选煤样)中,惰质组富集于S3(密度为>1.5g/cm^3浮选煤样)中,其中S3所含硅铝酸盐类矿物显著高于S2。且碱及碱土金属(alkali and alkaline earth metals, AAEM)多以可溶性形式存在,经酸洗处理后剩余矿物质主要为石英、高岭土及硅酸盐类。在选用不同煤样进行热解特性分析发现,碱及碱土金属的存在会抑制热解主反应阶段的挥发分释放,而在二次脱气阶段,AAEM矿物质则会提高挥发分的释放速率。且在热解实验中发现,AAEM在热解中会充当煤大分子结构的交联点,降低热解焦油产率。对比不同显微组分发现,惰质组热稳定性更强,镜质组中烷烃侧链较多,芳香度较小,更易受热断裂。采用Doyle积分法确定了沙尔湖煤热解反应的动力学参数。 展开更多
关键词 沙尔湖煤 酸洗 热解 傅里叶红外光谱 动力学参数
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活性与非活性克雷伯氏菌对水中Pb2+的吸附性能
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作者 李立雄 刘树丽 +4 位作者 徐晓军 李萱 段正洋 宋淑敏 赵静 《环境科学与技术》 CAS CSCD 北大核心 2019年第1期85-93,共9页
针对从云南某矿山废水中分离出的1株克雷伯氏菌(Klebsiella sp.),研究其活性菌体(AK)和非活性菌体(IK)对水溶液中Pb2+的吸附性能。研究了pH、吸附剂用量、反应时间和初始Pb2+浓度、背景阴离子和共存阳离子对AK和IK吸附Pb2+的影响,采用Z... 针对从云南某矿山废水中分离出的1株克雷伯氏菌(Klebsiella sp.),研究其活性菌体(AK)和非活性菌体(IK)对水溶液中Pb2+的吸附性能。研究了pH、吸附剂用量、反应时间和初始Pb2+浓度、背景阴离子和共存阳离子对AK和IK吸附Pb2+的影响,采用Zeta电位和FTIR分析进一步阐述2种吸附剂吸附Pb2+的差异。在不同的实验条件下,AK对Pb2+的吸附量均高于IK。AK和IK的吸附动力学均符合伪二级动力学模型,吸附等温线都能更好地使用Langmuir模型拟合。背景阴离子NO32-、Cl-和SO42-对AK和IK去除Pb2+影响不大。Pb2+、Zn2+和Cd2+3种重金属离子共存时,AK和IK对Pb2+的吸附具有选择性。Zeta电位和FTIR分析表明,AK比IK具有更强的结合Pb2+的能力,参与反应的基团主要是羟基、氨基和羧基。 展开更多
关键词 克雷伯氏菌 吸附剂 PB2+ 动力学 ZETA电位
Enhanced Biogas Production from the Anaerobic Batch Treatment of Banana Peels 预览
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作者 Spyridon Achinas Janneke Krooneman Gerrit Jan Willem Euverink 《工程(英文)》 2019年第5期970-978,共9页
Waste disposal management and the energy crisis are important challenges facing most countries.The fruit-processing industry generates daily several tons of wastes,of which the major share comes from banana farms.Anae... Waste disposal management and the energy crisis are important challenges facing most countries.The fruit-processing industry generates daily several tons of wastes,of which the major share comes from banana farms.Anaerobic digestion(AD)technology has been applied to the treatment of wastewater,animal slurry,food waste,and agricultural residues,with the primary goals of energy production and waste elimination.This study examines the effect of organic loading(OL)and cow manure(CM)addition on AD performance when treating banana peel waste(BPW).The maximum daily biogas production rates of banana peels(BPs)with a CM content of 10%,20%,and 30%at 18 and 22 g of volatile solids(gvs)per liter were 50.20,48.66,and 62.78 mL(gvs.d)^-1 and 40.49,29.57,and 46.54 mL(gvs.d)^-1,respectively.However,the daily biogas yield showed no clear interdependence with OL or CM content.In addition,a kinetic analysis using first-order and cone models showed that the kinetic parameters can be influenced by the process parameters. 展开更多
关键词 BIOGAS Banana peels Cow manure Anaerobic treatment Batch test Kinetic study
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Prescribed performance neural control to guarantee tracking quality for near space kinetic kill vehicle 预览
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作者 ZHANG Tao LI Jiong +2 位作者 LI Weimin WANG Huaji LEI Humin 《系统工程与电子技术:英文版》 SCIE EI CSCD 2019年第3期573-586,共14页
A prescribed performance neural controller to guarantee tracking quality is addressed for the near space kinetic kill vehicle (NSKKV) to meet the state constraints caused by side window detection. Different from the t... A prescribed performance neural controller to guarantee tracking quality is addressed for the near space kinetic kill vehicle (NSKKV) to meet the state constraints caused by side window detection. Different from the traditional prescribed performance control in which the shape of the performance function is constant, this paper exploits new performance functions which can change the shape of their function according to different symbols of initial errors and can ensure the error convergence with a small overshoot. The neural backstepping control and the minimal learning parameters (MLP) technology are employed for exploring a prescribed performance controller (PPC) that provides robust tracking attitude reference trajectories. The highlight is that the transient performance of tracking errors is satisfactory and the computational load of neural approximation is low. The pseudo rate (PSR) modulator is used to shape the continuous control command to pulse or on-off signals to meet the requirements of the thruster. Numerical simulations show that the proposed method can achieve state constraints, pseudo-linear operation and high accuracy. 展开更多
关键词 PRESCRIBED PERFORMANCE control near space kinetic KILL vehicle (NSKKV) neural approximation minimal learning parameter (MLP) pseudo rate (PSR) MODULATOR
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Theoretical study of overstretching DNA–RNA hybrid duplex
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作者 杨东尼 钟振声 +2 位作者 刘文钊 Thitima Rujiralai 马杰 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第6期477-485,共9页
DNA–RNA hybrid(DRH) plays important roles in many biological processes. Here, we use a thermodynamic theory to analyze the free energy and unpeeling properties of the overstretching transition for the DRH molecule an... DNA–RNA hybrid(DRH) plays important roles in many biological processes. Here, we use a thermodynamic theory to analyze the free energy and unpeeling properties of the overstretching transition for the DRH molecule and compare the results with double-helix DNA. We report that the RNA strand of DRH is easier to get unpeeled than the DNA strand while the difficulty in unpeeling the double helix DNA lies in between. We also investigate the sequence effect, such as GC content and purine content, on the properties of unpeeling the DRH. Further, to study the temperature effect, the forcetemperature phase diagram of DRH and DNA are calculated and compared. Finally, using a kinetic model, we calculate the force–extension curves in the DRH stretching and relaxation process under different pulling rates and temperatures. Our results show that both pulling rate and temperature have important influences on the stretching and relaxation kinetics of unpeeling the DRH. Putting all these results together, our work provides a comprehensive view of both the thermodynamics and kinetics in DRH overstretching. 展开更多
关键词 DNA–RNA HYBRID mechanical properties overstretching THERMODYNAMIC and KINETIC model
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