NEW EQUATION FOR CORRELATING EXPERIMENTAL DATA WITH TWO VARIABLES

The equation mostly used for correlating experimental data is normal polynomial:f(x,t) = c 0(t) +c 1(t)x+c 2(t)x 2+…+c n(t)x n.However correlation with this polynomial is undesirable when the curved surface formed by experimental data is not smooth or the correlating range of correlation is too large.In this paper, a new correlating equation for this purpose is proposed.There are no undetermined coefficients in the new equation. When this new equation is used for correlating different kinds of experimental data (curved surface), smaller errors will always be obtained in comparison with the normal polynomial

拟合实验数据的新方程——非整数幂多项式方程

将实验数据拟合成方程在科学研究和工程计算上具有十分重要的作用。目前,拟合实验数据最常用的是整数幂多项式f(x)=c_0+c_1x+c_2x~2+…+c_nx~n,但是用此多项式拟合各类数据时有时误差较大。本文提出一个新方程,即双系列非整数幂多项式g(x)=c_0+c_1x~0+…+c_kx~(ka)+c_(k+1)x~[(k+1)b]+…+c_nx~(nb),式中a,b为参数,c_i(i=0,1,2,…,n)为待定系数。在拟合各类实验数据时,新方程总是优于整数幂多项式

A Novel Method for Preparing γ-Al_2O_3

经蒸发浓缩氯化铝、氨水与扩孔剂草酸铵的混合溶液,生成氢氧化铝沉淀物,再经加热分解除去NH4Cl,所得粉末成型后在550℃下煅烧转化为γ Al2O3.着重考察扩孔剂加入量,分解温度等对产品性质的影响.与常规制备γ Al2O3方法比较,本方法省去了老化、过滤、洗涤等步骤,具有缩短制备周期、保护环境等优点.本方法所制γ Al2O3孔体积大,孔分布集中,压碎强度高.A novel method for preparingγAl2O3 is provided with the procedure as follows :(1) a mixing solution composed of AlCl3,NH+4,H2O and ammonium oxalate is concentrated by heating and resulting in the deposition of Al(OH)3;(2)drying the deposit;(3)decomposing the deposit and NH4Cl being retrieved;(4)the powder from step(3)being pelleliged(5)calcining the pellet at 550℃ for 4hr.Compared with the usual technology,this new method has the advantages of needlessness of preparing steps such as aging,filter and washing,and the dispose of the washing liquid.The γAl2O3 obtained by the method is characterized by large pore volume,narrow pore distribution and high crushing strength for pellet

Methods of Deriving a Reaction Mechanism from Its Rate Equation

将化学反应视为抽象的“化学流”,提出“完全速率方程”的概念,并阐述其物理意义,考察了完全速率方程的各种破缺形式及其所对应的反应历程的特性及自催化作用对速率方程的影响.通过举例说明,归纳总结了由速率方程推演反应历程所应遵循的原理和规则.Supposing that the concentrations of intermediates are invariable during the course of a chemical reaction,there will be a rate equation with full form called full rate equation:γ_(ful)=(F_f-F_b)/(F_(m-f)-F_(m-b)).The full rate equation,if a chemical reaction is regarded as chemical flow,has its physical meanings.F_f 、F_b、F_(m-f)、F_(m-b) can be called forward full-flow,backward full-flow,forward flow of decreasing intermediates and backward flow of decreasing intermediates respectively.F_f is defined as multiplication of the forward rate equation of every element reaction(ER) and the definitions of F_b、F_(m-f) and F_(m-b) are in analogy to F_f.The reaction mechanism(pathway) corresponding the full rate equation has three features:(1) every ER is reversible;(2) at least one molecule of reactants does not take part in first-step ER;(3) at least one molecule of products does not emerge in last-step ER.In most cases,the full rate equation appears as a certain kind of short forms.For example,if at least one of ERs is irreversible,then F_b=0.According to the physical meanings of rate equation and the understanding of the intermediates of the reaction concerned,we can easily derive the reaction pathway.Meanwhile the effects of autocatalysis on the form of the rate equation are also discussed

New Equation for Correlating Data of Substance's Saturated Pressure

在已有实验数据的基础上,提出一个拟合液体饱和蒸气压数据的新方程:lnp=(1-x)lnp0+xlnp1+xΣCi(1-xi),并与被认为是最为准确的蒸气压拟合显函数方程Wagner方程进行比较.应用新方程,利用MATLAB6.1软件,拟合149种有机物质共2114个实验点的蒸气压数据,新方程的总平均相对误差(ARD)为0.2625%,而Wagner方程的ARD为1.606%,表明新方程比Wagner方程有了很大的改进.It is important to describe quantitatively the variation of a substance's saturated pressure with temperature by a suitable equation.For example,it will be possible to calculate other thermodynamics data such as the evaporation heat and viscosity of substances using this kind of equation.The object of this work is to develop such an equation with simple form (therefore we can conduct mathematic operations especially differentiation and integration on it) and satisfactory calculating errors.As a result,a new equation is proposed for correlating data of substance's saturated pressure:lnp=(1-x)lnp_0+xlnp_1+x∑ni=1C_i(1-x~i).(Using MATLAB) 6.1 software,2 114 data of 149 organic substances including paraffin,olefin,aromatic,alcohol,aether,ketone,acid,aldehyde,phenol,butter,amine and cyanogens is correlated by the new equation with total average relative deviation (ARD) equal to 0.262 5%.By comparison,the ARD of well-known Wagner's equation under the same conditions is 1.606%,showing that the new equation is of advancement

CO_2电催化还原制烃类产物的研究进展

应用可再生能源驱动CO2电催化还原制备燃料,是目前清洁能源发展最具前景的方向之一。本文综述了以气态烃类（CH4、C2H4）为目标产物的CO2电催化还原的研究进展,分别介绍了电催化材料、电解质溶液以及反应机理的研究现状。指出在水溶液电解质中,电催化材料需兼具烃类产物的高选择性与电化学析氢反应的抑制能力,Cu与Cu基材料是电催化材料的首选,Cu的氧化物由于其丰富的结构特征拓宽了电催化材料优选范围。水溶液电解质的性质会显著影响CO2电催化还原产物的选择性;非水溶液或痕水溶液电解质由于可以显著抑制析氢反应,将会进一步拓宽电催化材料的优选范围。最后介绍了CO2电催化还原机理研究的现状,指出原位电化学谱学方法的应用与CO2电催化还原机理模型研究工作的开展,将成为人们深入认识以烃类为目标产物的CO2电催化还原反应的关键,并有利于指导电催化材料与电解质材料的研究开发

Stability Studies for a Membrane Electrode Assembly Type CO2 Electro-Reduction Electrolytic Cell

电化学还原CO2可实现CO2的资源化转化,是缓解因其过度排放所导致诸多环境问题的关键技术. 本文提出了一种膜电极（membrane electrode assembly,MEA）构型CO2还原电解单池的结构设计,可同步实现气体扩散阴极两侧CO2的供给与电解质液层的更新. 基于该MEA构型电解池,实验考察了电解质液层中KHCO3浓度和更新与否对氮掺杂石墨烯锚定的Ni电极表面CO2电还原制备CO的反应活性、产物分布与稳定性的影响. 结果表明,若电流密度低于5 mA·cm-2,KHCO3浓度显著影响电解电势而非产物分布. CO2还原电解单池在稳定运行中存在着“可逆”与“不可逆”两种衰减模式. 其中,阴极/电解质界面处催化剂的流失是 “不可逆”衰减形成的原因;而电解质液层中KHCO3溶液的流失导致了MEA构型CO2还原单池的“可逆”衰减,周期性更新KHCO3电解质是降低其“可逆”衰减的有效方法.Electro-catalytic reduction is an efficient way to achieve resourcable transformation of CO2, which is one of the important techniques to solve the global environmental problems originated from excessive CO2 emission. In this study, a membrane electrode assembly(MEA) type CO2 electro-reduction electrolytic cell was constucted, which enables CO2 feeding and real-time KHCO3 aqueous updating on both sides of the cathode gas diffusion electrode (GDE). By means of the electrolytic cell, effects of KHCO3 concentration and updating inside the liquid electrolytic chamber on CO2 electro-reduction activity, production distribution and stability were investigated. The experimental results suggested that the KHCO3 concentration exerted strong influence on the cell voltage rather than the production distribution for the current densities lower than 5 mA·cm-2. The performance of MEA type CO2 electro-reduction cell decayed in both “reversible” and “irreversible” ways. Catalysts leaking at the GDE/liquid electrolyte interface might be respossible for the cell “irreversible” decay. Meanwhile, th leakage of KHCO3 aqueous electrolyte arose from gas accumulation in the liquid electrolytic chamber contributed to the “reversible” degradation, which could be recovered effectively by updating the KHCO3 aqueous electrolyte.辽宁省自然科学基金项目（No.201602162）、大连理工大学GF创新基金项目（No.DUT18GF308）和国家电网公司科技项目（No.SGRI-DL-71-16-015）资助通讯作者:毛庆,黄延强E-mail:[email protected];[email protected]:MAOQing,HUANGYan-qiangE-mail:[email protected];[email protected]. 大连理工大学化工学院,辽宁 大连 116023 2. 中国科学院大连化学物理研究所,航天催化与新材料研究室,辽宁 大连 116023 3. 全球能源互联网研究院,北京 1022001. School of Chemical Engineer, Dalian University of Technology, Dalian 116024, China2. Laboratory of Aerospace Catalysts and New Materials, Dalian Institute of Chemical Physics, Chinese Academy of Science, Dalian 116023, China3. Global Energy Interconnection Research Institute, Beijing 102200, Chin

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies