One‑Step Gas-Solid‑Phase Diffusion‑Induced Elemental Reaction for Bandgap‑Tunable Cu_(a)Agm_(1)Bim_(2)I_(n)/CuI Thin Film Solar Cells

Lead-free inorganic copper-silver-bismuth-halide materials have attracted more and more attention due to their environmental friendliness,high element abundance,and low cost.Here,we developed a strategy of one-step gas-solid-phase diffusioninduced reaction to fabricate a series of bandgap-tunable Cu_(a)Agm_(1)Bim_(2)I_(n)/CuI bilayer films due to the atomic diffusion effect for the first time.By designing and regulating the sputtered Cu/Ag/Bi metal film thickness,the bandgap of Cu_(a)Agm_(1)Bim_(2)I_(n)/CuI could be reduced from 2.06 to 1.78 eV.Solar cells with the structure of FTO/TiO_(2)/Cu_(a)Agm_(1)Bim_(2)I_(n)/CuI/carbon were constructed,yielding a champion power conversion efficiency of 2.76%,which is the highest reported for this class of materials owing to the bandgap reduction and the peculiar bilayer structure.The current work provides a practical path for developing the next generation of efficient,stable,and environmentally friendly photovoltaic materials.

FINITE ELEMENT METHOD FOR SOLVING TWO-DIMENSIONAL DIFFUSION-REACTION EQUATIONS OF BOUNDARY LAYER TYPE IN POROUS CATALYST PELLET

In this paper,finite element method(FEM)is used to solve two-dimensional diffu-sion-reaction equations of boundary layer type.This kind of equations are usually too complicatedand diffcult to be solved by applying the traditional methods used in chemical engineering becauseof the steep gradients of concentration and temperature.But,these difficulties are easy to be over-comed when the FEM is used.The integraded steps of solving this kind of problems by the FEMare presented in this paper.By applying the FEM to the two actual examples,the conclusion can bereached that the FEM has the advantages of simplicity and good accuracy.

Different Influence of Structure Elements of Ionic Liquids on the Knoevenagel Condensation Reactions

Ionic liquids (ILs) with 1,3-disubstituted imidazolium cations and the dimethyl phosphate (DMP) anion, as well as the chloride anion were prepared and characterized by 1H NMR spectra, chromatographic and titrimetric purity control, and determination of the moisture content and thermal stability. ILs with the DMP anion decompose only at temperatures above 240°C. These ILs were tested as both reaction media (solvents) and catalysts for the Knoevenagel condensation reaction. The impact of the most significant structure elements of ILs was evaluated for the rates and yields of the condensation reaction. IL anions have the greatest effect on the condensation reactions, and even the chloride anion has some catalytic effect on the Knoevenagel condensation. Side chains in the imidazolium cations influence the reaction course very little. The ability of the imidazolium cations to form hydrogen bonding with the transition state of the condensation reaction leads to a remarkable slowdown in the reaction rates.

Finite volume element method for analysis of unsteady reaction-diffusion problems

A finite volume element method is developed for analyzing unsteady scalar reaction-diffusion problems in two dimensions. The method combines the concepts that are employed in the finite volume and the finite element method together. The finite volume method is used to discretize the unsteady reaction-diffusion equation, while the finite element method is applied to estimate the gradient quantities at cell faces. Robustness and efficiency of the combined method have been evaluated on uniform rectangular grids by using available numerical solutions of the two-dimensional reaction-diffusion problems. The numerical solutions demonstrate that the combined method is stable and can provide accurate solution without spurious oscillation along the high-gradient boundary layers.

Discrete formulation of mixed finite element methods for vapor deposition chemical reaction equations

The vapor deposition chemical reaction processes, which are of extremely extensive applications, can be classified as a mathematical model by the following governing nonlinear partial differential equations containing velocity vector, temperature field, pressure field, and gas mass field. The mixed finite element （MFE） method is employed to study the system of equations for the vapor deposition chemical reaction processes. The semidiscrete and fully discrete MFE formulations are derived. And the existence and convergence （error estimate） of the semidiscrete and fully discrete MFE solutions are demonstrated. By employing MFE method to treat the system of equations for the vapor deposition chemical reaction processes, the numerical solutions of the velocity vector, the temperature field, the pressure field, and the gas mass field can be found out simultaneously. Thus, these researches are not only of important theoretical means, but also of extremely extensive applied vistas.

ALTERNATING DIRECTIONFINITE ELEMENT METHOD FORSOME REACTION DIFFUSION MODELS

This paper is concerned with some nonlinear reaction - diffusion models. To solve this kind of models, the modified Laplace finite element scheme and the alternating direction finite element scheme are established for the system of patrical differential equations. Besides, the finite difference method is utilized for the ordinary differential equation in the models. Moreover, by the theory and technique of prior estimates for the differential equations, the convergence analyses and the optimal L2- norm error estimates are demonstrated.

A Second Order Characteristic Mixed Finite Element Method for Convection Diffusion Reaction Equations

A combined approximate scheme is defined for convection-diffusion-reaction equations. This scheme is constructed by two methods. Standard mixed finite element method is used for diffusion term. A second order characteristic finite element method is presented to handle the material derivative term, that is, the time derivative term plus the convection term. The stability is proved and the L2-norm error estimates are derived for both the scalar unknown variable and its flux. The scheme is of second order accuracy in time increment, symmetric, and unconditionally stable.

基于CREB/BDNF信号通路探讨NA-1对新生大鼠缺氧缺血性脑损伤的保护作用

目的:探讨突触后密度蛋白-95(PSD-95)抑制剂(NA-1)对新生大鼠缺氧缺血性脑损伤(HIBD)海马区环磷酸腺苷反应元件结合蛋白(CREB)/脑源性神经营养因子(BDNF)信号通路的影响。方法:将7 d龄新生SD大鼠随机分为正常对照组、HIBD组、NA-1组(腹腔注射10μg/g NA-1溶液)和NA-1+CREB抑制剂H89组(腹腔注射10μg/g NA-1溶液+2μg/L H89溶液),每组15只。采用Rice法制备HIBD模型,评估大鼠神经行为变化;2,3,5-三苯基氯化四氮唑(TTC)染色和尼氏染色观察大鼠脑组织病理变化;蛋白免疫印迹法(Western Blot)检测大鼠海马区PSD-95和CREB/BDNF信号通路表达情况。结果:与正常对照组比较,HIBD组大鼠趋地反射和悬崖逃避反射时间延长,前肢握力时间缩短,脑梗死体积、海马区PSD-95蛋白表达增加,尼氏阳性细胞数、磷酸化CREB(p-CREB)/CREB、BDNF蛋白表达减少(P<0.05);与HIBD组比较,NA-1组趋地反射和悬崖逃避反射时间缩短,前肢握力时间延长,脑梗死体积、海马区PSD-95蛋白表达减少,尼氏阳性细胞数、p-CREB/CREB、BDNF蛋白表达增加(P<0.05);添加H89可部分逆转NA-1的作用。结论:NA-1可改善新生大鼠HIBD后的神经行为,减少脑梗死体积和神经元凋亡,可能与激活CREB/BDNF信号通路有关。

How accurately can we predict synthesis cross sections of superheavy elements？

Synthesis of superheavy elements beyond oganesson is facing new challenges as new target–projectile combinations are necessary. Guidance from models is thus expected for future experiments. However, hindered fusion models are not well established and predictions in the fission barriers span few MeVs. Consequently, predictions are not reliable. Strategies to constrain both fusion hindrance and fission barriers are necessary to improve the predictive power of the models. But, there is no hope to get an accuracy better than one order of magnitude in fusion–evaporation reactions leading to superheavy elements synthesis.

Acting mechanism of F,K,and Na in the solid phase sintering reaction of the Baiyunebo iron ore

The effect of F,K,and Na on the solid phase reaction of the Baiyunebo iron ore was investigated by differential thermal analysis （DTA） and X-ray diffraction（XRD）.It has been identified that alkaline elements K and Na in the Baiyunebo ore instigate the formation of low melting point compounds Na2SiO3 and Na2O·Fe2O3 and the generation of molten state in the solid phase sintering.Element F in the Baiyunebo ore facilitates the formation of cuspidine compound 3CaO·2SiO2·CaF2 in the solid phase reaction.The cuspidine compound is kept in solid as one of the final products through the entire sintering process due to its high melting point.In the sintering process,CaF2and SiO2 react with CaO first and form 3CaO·2SiO2·CaF2 and 3CaO·2SiO2,so the formation of ferrites,Na2O·Fe2O3,and 2CaO·Fe2O3 is inhibited.

Effects of rare earth element lanthanum on the microstructure of copper matrix diamond tool materials

Effects of rare earth element La on the microstructure of Cumatrix diamond tools were researched under the conditions of variousmaterials components and the process parameters in order to improvematerials properties. SEM, XPS and X-ray were used to investigate thefracture section, microstructure and the element valence inmaterials. The Results shown that the combination of rare earthelement La and transition element Ti is advantageous to the bondingstate Between diamond particles and matrix, so it can improve thematerials properties. Suitable sintering temperature is 790 deg. C.

Determination of impurity elements in MnZn ferrites by inductively coupled plasma mass spectrometry

An inductively coupled plasma mass spectrometry(ICP-MS) method was developed for the determination of Na, Mg, Al,K, Ca, Ti, Cr, Co, Ni, Cu, Ga, As, Mo, Ag, Cd and Pb in MnZn ferrites. The sample was digested by HNO3+HCl with microwave digestion followed by dilution with ultrapure water, then the above 16 impurity elements in the solution were analyzed directly by ICP-MS. The impurity elements were introduced by the helium gas or hydrogen gas into the octopole reaction system(ORS) to eliminate the polyatomic interferences caused by the high salty matrixes. The matrix effect was minimized through matrix matching,and Be, Y and Rh were used as internal standard elements. The working parameters of the instrument were optimized. The results show that the method has good precision and high accuracy. The detection limits for the investigated elements are in the range of0.9-37.5 ng/L, the relative standard deviation of each element is within 1.1%-4.8%, and the recovery of each element is 90%-108%.

Stable Isotope and Element Geochemistry of Saline Springs in Evaporite-bearing Mengla Basin,South Yunnan,China

1 Introduction Mengla Basin is a sub-basin in southern evaporitebearing Lanping-Simao Basin.There are many salt springs in the basin.In 2012,11 spring samples were collected for analyses of chemistry and boron,hydrogen and oxygen

卧式反应釜电磁感应加热设计

针对大型反应釜的感应加热难以进行大量实验验证的问题,通过将理论计算与有限元仿真相结合的方式,对计算得出的参数进行优化,选择合适的输出功率和谐振频率,完成感应器的设计。通过仿真可以更好对比不同匝数、自热对流和搅拌轴对加热的影响,更直观地查看工件温度分布情况,缩小计算参数误差,实现反应釜加热的工艺要求。

Chemical reaction effects on unsteady MHD flow past semi-infinite vertical porous plate with viscous dissipation

The chemical reaction effect on an unsteady magnetohydrodynamic （MHD） flow past a semi-infinite vertical porous plate with viscous dissipation is analyzed. The governing equations of motion, energy, and species are transformed into ordinary differential equations （ODEs） using the time dependent similarity parameter. The resultant ODEs are then solved numerically by a finite element method. The effects of various parameters on the velocity, temperature, and concentration profiles are presented graphically, and the values of the skin-friction, Nusselt number, and Sherwood number for various values of physical parameters are presented through tables.

Determination of Major, Minor and Trace Element Compositions of the Gd₂O₂S:Pr,Ce Scintillation Ceramics with Neutron Activation Analysis

Neutron activation analysis technique of the Gd2O2S:М scintillation ceramics was developed. The concentrations of 15 trace, minor and major elements (As, Ce, Co, Cr, Cs, Eu, Fe, La, Sc, Tb, Zn, Zr, Pr, Gd, Na) have been measured with the instrumental neutron activation analysis of the Gd2O2S:Pr sample. The concentrations range of the determined elements is from 3 × 10-8 to 2.0% in mass. The determination limit of the elements was calculated to be (0.6 - 1.3 × 10-8% in mass).

The Astrophysical Processes of Cosmological Hydrogen that Generate the Chemical Elements that Make up the Universe

The objective of the present article is to explain how all the chemical elements were formed from the big bang generated element: hydrogen. The methodology used was to analyze the main cosmological and astrophysical processes in order to explain the origin of all the known chemical elements. The main results are: Hydrogen cannot be formed in any part of the actual universe;it must come from the Big Bang. Helium and a little bit of lithium can have a cosmological origin associated to the Big Bang nucleosynthesis and the recombination process. The elements with an atomic number between 3 and 26 were, and continue to be, synthetized by nuclear fusion reactions inside the core of massive stars and liberated by explosion when the stars go supernovae, at the end of their lives. In the process of going supernova, elements with a medium atomic number, between 27 and 40, are created. All the elements with an atomic number larger than 40 were generated by neutron star collisions. When Mendeleev and Lothar Meyer designed an ordered arrangement of chemical elements, their tables included the 63 chemical elements known in 1869. A century and a half later, the known elements are 118. By studying different topics related to the elements, it was possible to uncover fundamental particles, such as quarks and leptons, and the strong and weak nuclear forces that form the baryonic part of the universe. The Sun was formed 6000 million years ago and its planets, including earth, were formed 4600 million years ago when and where there were debris of different stars that went supernova, in particular 1A type, and also debris, of at least one of a binary neutron star collision, so to attain, all the elements that have been identified in the solar system, and especially in earth. In addition, the current “periodic table” includes 26 synthetic elements that were produced in neutron star collisions but, because of their short lifetimes, they are not found, on earth. The vast quantities of the elements, produced during the aforementioned astrophysical processes, clustered into planets, stars and galaxies;and at least in one planet, our earth, some chemical elements organized themselves into living creatures.

CRP Binding Kinetics Enhancement Using Local Narrowing into a Bent Channel: Finite Element Analysis

Binding kinetics enhancement of a microfluidic biosensor into a micro-channel through the application of a supplementary mechanism has received tremendous attention because of the obtained significant enhancement factor. However, biosensor’s performance enhancement using only simple channel engineering is still rarely realized. Herein, we present a novel design of a complex reactive protein (CRP) biosensor into a U-shaped channel with a sensitive membrane located in the middle of the bent zone. Various critical factors affecting the equilibrium binding time are numerically investigated. The turn geometry is then optimized when the arc length along the inner and outer radii is almost the same, which leads to locally minimizing the channel height overhead the reaction surface and improves the analyte transport towards the sensing area. The numerical studies reveal that applying a local narrowing above the reaction surface can notably enhance the trapping and the surface formation of complex antibody-antigen, thus upgrading the biosensor performance. This work puts a significant advance towards microfluidic channel engineering and the exploration of micro-flow injection experimental studies.

Modification of Glucose Molecules with Alkali Elements as a Method to Dissolve Cancer Cells

Cancer cells are irresponsive to the central control of the cell growth mechanisms. It is difficult to turn on the responsive mechanism of cancer cells because the cells are completely dissociated from the central command and on their own in terms of cell division and growth. Precisely, this is the reason why they are at risk to the health of humans and/or any biological entities. Instead of trying to reconnect the central command of the growth control mechanism to cancer cells that are already out of the range, we present a method for using the cancer cell’s own irresponsive and uncontrolled growth mechanism to their disadvantage and destroy the cancer cells. We found that this is achievable in an atomic/molecular level study of the glucose molecule, which is the primary food source used for growth and energy generation by all cells in the body, including cancer cells. Testimonials of the clinical trial of the supplement provide proof of dramatic recovery from the advanced stage of cancer in seven days.

NUMERICAL SOLUTION OF A NONLINEAR REACTION-DIFFUSION EQUATION

A nonlinear reaction-diffusion equation is studied numerically by a Petrov-Galerkin finite element method, which has been proved to be 2nd-order accurate in time and 4th-order in space. The comparison between the exact and numerical solutions of progressive waves shows that this numerical scheme is quite accurate, stable andefflcient. It is also shown that any local disturbance will spread, have a full growth and finally form two progressive waves propagating in both directions. The shape and the speed of the long term progressive waves are determined by the system itself, and do not depend on the details of the initial values.