一道化学动力学题的研讨     

湛钟 《贵州教育学院学报》2005,16(2):68-69

把一道化学动力学题的内容形式和解题方法做三种变化处理，能达到启发思维、增强兴趣的效果，并能更全面、深刻地理解化学反应动力学原理。  相似文献   

Diffusion-Controlled Adsorption Kinetics of Triton X-100 at Air/Solution Interface     

刘俊吉  王创业 《天津大学学报(英文版)》2004,10(3)

Theadsorptionkineticsofaqueoussurfactantsolu tionsatair/solutioninterfaceplaysamostimportantroleinwetting ,foamstability ,emulsionstability,fastcoat ing,detergency ,surfaceoscillation ,adsorptivebubbleseparationtechnique,etc.Theadsorption processcon sistsoftwosteps:thefirststepisthetransportofsurfac tantmoleculesfromthebulkphasetothesubsurfaceduetoaconcentrationgradient,i.e .thediffusionstep;thesecondoneisthetransportofmoleculesfromthesubsur facetothesurface,i.e.theadsorptionstep.Iftherateofth…  相似文献   

The effects of baseball bat mass properties on swing mechanics,ground reaction forces,and swing timing     

Walter A. Laughlin  Kyle T. Aune  Alek Z. Diffendaffer 《Sports biomechanics / International Society of Biomechanics in Sports》2016,15(1):36-47

Swing trajectory and ground reaction forces (GRF) of 30 collegiate baseball batters hitting a pitched ball were compared between a standard bat, a bat with extra weight about its barrel, and a bat with extra weight in its handle. It was hypothesised that when compared to a standard bat, only a handle-weighted bat would produce equivalent bat kinematics. It was also hypothesised that hitters would not produce equivalent GRFs for each weighted bat, but would maintain equivalent timing when compared to a standard bat. Data were collected utilising a 500 Hz motion capture system and 1,000 Hz force plate system. Data between bats were considered equivalent when the 95% confidence interval of the difference was contained entirely within ±5% of the standard bat mean value. The handle-weighted bat had equivalent kinematics, whereas the barrel-weighted bat did not. Both weighted bats had equivalent peak GRF variables. Neither weighted bat maintained equivalence in the timing of bat kinematics and some peak GRFs. The ability to maintain swing kinematics with a handle-weighted bat may have implications for swing training and warm-up. However, altered timings of kinematics and kinetics require further research to understand the implications on returning to a conventionally weighted bat.  相似文献   

催化动力学光度法测定痕量铜的综述     

黄晓东 《闽江学院学报》1995,(1)

本文综述我国催化动力学光度法测定痕量铜的状况,提出一些尚待开发新指示反应的设想,并介绍提高催化动力学法灵敏度的两个新途径。  相似文献   

Identification of types of landings after blocking in volleyball associated with risk of ACL injury     

David Zahradnik  Daniel Jandacka  Roman Farana  Jaroslav Uchytil  Joseph Hamill 《European Journal of Sport Science》2017,17(2):241-248

Landing with a low knee flexion angle after volleyball block jumps may be associated with an increased risk of anterior cruciate ligament (ACL) injury. The aim of the present study was to identify the types of volleyball landings after blocks where the knee flexion angle is found to be under a critical knee flexion angle value of 30° at the instant of the first peak of the ground reaction force (GRF). Synchronized kinematic and kinetic data were collected for each trial. T-tests were used to determine if each knee flexion angle at the instant of the peak GRF was significantly different from the critical value of 30°. A repeated measures ANOVA was used to compare knee flexion angle, time to first peak and the magnitude of the first peak of the resultant GRF and knee stiffness. Significantly lower knee flexion angles were found in the “go” landing (p?=?.01, ES?=?0.6) and the “reverse” landing (p?=?.02, ES?=?0.6) only. The results for knee flexion angle and GRF parameters indicated a significant difference between a “reverse” and “go” and other types of landings, except the “side stick” landing for GRF. The “reverse” and “go” landings may present a risk for ACL injury due to the single-leg landing of these activities that have an associated mediolateral movement.  相似文献   

SBR法短程硝化动力学分析     

张英慧  赵海燕  赵剑强  黎圣 《西安文理学院学报》2011,(2):38-41

针对实验室中SBR短程硝化反硝化工艺的硝化动力学进行研究分析.通过维持反应器内水温不变,合理控制溶解氧浓度和氨氮浓度等反应条件,并应用MATLAB编程,分析大量实验数据,求出其动力学参数,最后得到短程硝化动力学方程.  相似文献   

Influence of vermicomposting on solid wastes decomposition kinetics in soils     

Nourbakhsh F 《Journal of Zhejiang University. Science. B》2007,8(10):725-730

The effect of vermicomposting on kinetic behavior of the products is not well recognized. An incubation study was conducted to investigate C mineralization kinetics of cow manure, sugarcane filter cake and their vermicomposts. Two different soils were treated with the four solid wastes at a rate of 0.5 g solid waste C per kg soil with three replications. Soils were incubated for 56 d. The CO2-C respired was monitored periodically and a first-order kinetic model was used to calculate the kinetic pa-rameters of C mineralization. Results indicated that the percentage of C mineralized during the incubation period ranged from 31.9% to 41.8% and 55.9% to 73.4% in the calcareous and acidic soils, respectively. The potentially mineralizable C (C0) of the treated soils was lower in the solid waste composts compared to their starting materials. Overall, it can be concluded that de-composable fraction of solid wastes has decreased due to vermicomposting.  相似文献   

Adapting the usage of enzyme unit to its definition     

YANG Ming-li  LUO Min  XIAN Xiao-hong 《重庆大学学报(英文版)》2011,10(1):23-25

The enzyme unit U, by its definition, is the amount of enzyme that catalyses the transformation of one micromole of substrate per minute under standard assay conditions. However, in practical use, it is identical with micromole or microgram per minute, which deviates from the essence of the definition as a measure of amount of substance. Such usage appears in many publications that involve enzyme kinetics and conveys obscure signification. In this article, we solved the confusion by regarding the unit U as a measure of amount of enzyme having a specified catalytic activity just like the basic SI unit mole (symbol mol) defined as the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kg of carbon 12. We introduced the concept of unit rate, ru, which is defined as the rate of a reaction mediated by 1 U enzyme, in calculating the enzyme units in an amount of enzyme so as to avoid the inconsistence of the expression with the definition of enzyme unit. The method can also be applied to the case of katal, the recommended SI unit of enzyme activity.  相似文献   

Vacuum pyrolysis characteristics of waste epoxy printed circuit boards     

ZHAN Zhi-hu  QIU Ke-qiang 《重庆大学学报(英文版)》2011,10(3):113-122

Vacuum pyrolysis was employed to dispose scrap brominated epoxy printed circuit boards (PCBs). Pyrolysis characteristics of waste PCBs under normal pressure and vacuum were investigated in this paper. A detailed study on the analysis of the elemental composition of PCBs and the pyrolysis products was performed. The thermal decomposition kinetics was measured by a thermogravimetric (TG) analyzer. The activation energy of pyrolysis under nitrogen atmosphere and vacuum were 193 kJ/mol to 206 kJ/mol and 145 kJ/mol to 165 kJ/mol, respectively. The composition of materials was analyzed by elemental analyzer. The pyrolysis products were analyzed by GC (gas chromatograph), GC-MS (chromatography and mass spectrometry) and FT-IR (Fourier transform infrared spectroscopy). Vacuum helped to increase the yield of pyrolysis oil. The liquid yield of PCBs pyrolysis at 15 kPa and normal pressure were 31.3? and 23.5?, respectively. The main components in pyrolysis oils were phenol, isopropyl-phenol, and their brominated substitution.  相似文献   

Extraction and stripping kinetics of copper （Ⅱ） by N902 using single drop technique     

朱萍  范泽云  吴金华  钱光人  周鸣 《上海大学学报(英文版)》2010,14(4):275-280

The kinetics of extraction and stripping of copper （Ⅱ） was investigated by the single drop technique with a new extractant N902 （a derivative of the salicylal-doxime） and the rate equations of extraction and stripping were derived, respectively. The apparent activation energies of extraction and stripping were estimated to be 20.14 kJ/mol and 30.0 k J/mol.  相似文献