Temperature-dependent photoluminescence on organic inorganic metal halide perovskite CH_3NH_3Pb I_(3-)Cl_ prepared on ZnO/FTO substrates using a two-step method

Temperature-dependent photoluminescence characteristics of organic-inorganic halide perovskite CH3NH3Pb I3-xClx films prepared using a two-step method on ZnO/FTO substrates were investigated. Surface morphology and absorption characteristics of the films were also studied. Scanning electron microscopy revealed large crystals and substrate coverage. The orthorhombic-to-tetragonal phase transition temperature was-140 K. The films＇ exciton binding energy was 77.6 ± 10.9 meV and the energy of optical phonons was 38.8 ± 2.5 meV. These results suggest that perovskite CH3NH3Pb I（3-x）Clx films have excellent optoelectronic characteristics which further suggests their potential usage in perovskitebased optoelectronic devices.

Applying the Dynamic Two-Step Method to Forecast Remaining Oil Distribution of Lower Series ,Xiaermen Oilfield

The distribution of remaining oil is often described qualitatively. The remaining oil distributed in the whole reservoir is calculated according to the characteristics of the space distribution of the saturation of remaining oil. Logging data are required to accomplish this. However, many such projects cannot be completed. Since the old study of remaining oil distribution could not be quantified efficiently, the ＂dynamic two-step method＂ is presented. Firstly, the water cut of every flow unit in one well at one time is calculated according to the comprehensive water cut of a single well at one time. Secondly, the remaining oil saturation of the flow unit of the well at one time is calculated based on the water cut of the flow unit at a given time. The results show that ＂dynamic two-step method＂ has characteristics of simplicity and convenience, and is especially suitable for the study of remaining oil distribution at high water-cut stage. The distribution of remaining oil presented banding and potato form, remaining oil was relatively concentrated in faultage neighborhood and imperfect well netting position, and the net thickness of the place was great. This proposal can provide an effective way to forecast remaining oil distribution and enhance oil recovery, especially applied at the high water-cut stage.

The convergence ball and error analysis of the two-step Secant method

Under the assumption that the nonlinear operator has Lipschitz continuous divided differences for the first order,we obtain an estimate of the radius of the convergence ball for the two-step secant method.Moreover,we also provide an error estimate that matches the convergence order of the two-step secant method.At last,we give an application of the proposed theorem.

Efficient hydrocarboxylation of alkynes based on carbodiimide‐regulated in situ CO generation from HCOOH:An alternative indirect utilization of CO_(2)

The role of carbodiimide as dehydrant in the chemo‐,regio‐and stereoselective Pd(Ⅱ/0)‐catalyzed hydrocarboxylation of various alkynes with HCOOH releasing CO in situ is reported for the first time to obtainα,β‐unsaturated carboxylic acids.Both symmetrical and unsymmetrical monoalkynes show good reactivity.Importantly,2,2’‐(1,4‐phenylene)diacrylic acid can also be synthesized in high yield through the dihydrocarboxylation of 1,4‐diethynylbenzene.Besides,an excellent result in gram scale experiment and TON up to 900 can be obtained,displaying the efficiency of this protocol.Notably,regulating the types and concentrations of dehydrant can control the CO generation,avoiding directly operating toxic CO and circumventing sensitivity issue to the CO amount.On the basis of the attractive features of formic acid including easy preparation through CO_(2) hydrogenation and efficient liberation of CO,this protocol using formic acid as bridging reagent between CO_(2) and CO can be perceived as an indirect utilization of CO_(2),offering an alternative method for preparing acrylic acid analogues.

A new two-step variational model for multiplicative noise removal with applications to texture images

Multiplicative noise removal problems have attracted much attention in recent years.Unlike additive noise,multiplicative noise destroys almost all information of the original image,especially for texture images.Motivated by the TV-Stokes model,we propose a new two-step variational model to denoise the texture images corrupted by multiplicative noise with a good geometry explanation in this paper.In the first step,we convert the multiplicative denoising problem into an additive one by the logarithm transform and propagate the isophote directions in the tangential field smoothing.Once the isophote directions are constructed,an image is restored to fit the constructed directions in the second step.The existence and uniqueness of the solution to the variational problems are proved.In these two steps,we use the gradient descent method and construct finite difference schemes to solve the problems.Especially,the augmented Lagrangian method and the fast Fourier transform are adopted to accelerate the calculation.Experimental results show that the proposed model can remove the multiplicative noise efficiently and protect the texture well.

Solution of Nonlinear Integro Differential Equations by Two-Step Adomian Decomposition Method (TSAM)

The Adomian decomposition method (ADM) can be used to solve a wide range of problems and usually gets the solution in a series form. In this paper, we propose two-step Adomian Decomposition Method (TSAM) for nonlinear integro-differential equations that will facilitate the calculations. In this modification, compared to the standard Adomian decomposition method, the size of calculations was reduced. This modification also avoids computing Adomian polynomials. Numerical results are given to show the efficiency and performance of this method.

Arrhenius relationship and two-step scheme in AF hyperdynamics simulation of diffusion of Mg/Zn interface

The accelerating factor （AF） method is a simple and appropriate way to investigate the atomic long-time deep diffusion at solid-solid interface. In the framework of AF hyperdynamics （HD） simulation, the relationship between the diffusion coefficient along the direction of z-axis which is normal to the Mg/Zn interface and temperature was investigated, and the AF＇s impact on the diffusion constant （D0） and activation energy （Q^＊） was studied. Then, two steps were taken to simulate the atomic diffusion process and the formation of new phases： one for acceleration and the other for equilibration. The results show that： the Arrhenius equation works well for the description of Dz with different accelerating factors; the AF has no effect on the diffusion constant Do in the case of no phase transition; and the relationship between Q＊ and Q conforms to Q^＊=Q/A. Then, the new Arrhenius equation for AFHD is successfully constructed as Dz=Doexp[-Q/（ART）]. Meanwhile, the authentic equilibrium conformations at any dynamic moment can only be reproduced by the equilibration simulation of the HD-simulated configurations. Key words： accelerating factor method; Arrhenius equation; two-steps scheme; Mg/Zn interface; hyperdynamic simulation

A Novel Method of Fabricating a Well-Faceted Large-Crystal Diamond Through MPCVD

A novel method was developed to deposit a large crystal diamond with good facets up to 1000 μm on a tungsten substrate using a microwave plasma enhanced chemical vapor deposition （MPCVD）. This method consists of two steps, namely single-crystal nucleation and growth. Prior to the fabrication of the well-faceted, large crystal diamond, an investigation was made into the nucleation and growth of the diamond which were affected by the O2 concentration and substrate temperature. Deposited diamond crystals were characterized by scanning electron microscopy and micro-Raman spectroscopy. The results showed that the conditions of single-crystal nucleation were appropriate when the ratio of H2/CH4/O2 was about 200/7.0/2.0, while the sub- strate temperature Ts of 1000℃ to 1050℃ was the appropriate range for single-crystal diamond growth. Under the optimum parameters, a well-faeeted large crystal diamond was obtained.

The Research on Biogas Power Generation by Two Step Method

The paper aims to demonstrate the system of SANYI biogas power generation by two-step method which can produce methane and generate electricity effectively and stably.So it can be stable synchronization meshwork energy source establishment and provide references to develop an effective and stable project of producing methane and generating electricity.

In-depth understanding of ionic liquid assisted perovskite film formation mechanism for two-step perovskite photovoltaics

Ionic liquids(ILs)have been widely applied in the one-step fabrication of perovskite with noticeable enhancement in the device performance.However,in-depth mechanism of ionic-liquid-assisted perovskite film formation is not well understood for also important two-step perovskite fabrication method,with better control of crystallization behavior.In this work,we introduced ionic liquid methylammonium formate(MAFa)into organic salt to produce perovskite film via a two-step method.Systematic investigations on the influence of MAFa on the perovskite thin film formation mechanism were performed.Ionic liquid is shown to assist lowering the perovskite formation enthalpy upon the density functional theory(DFT)calculation,leading to an accelerated crystallization process evidenced by in-situ UV-Vis absorption measurement.A gradient up-down distribution of ionic liquid has been confirmed by timeof-flight SIMS.Importantly,besides the surface passivation,we found the HCOO-can diffuse into the perovskite crystals to fill up the halide vacancies,resulting in significant reduction of trap states.Uniform perovskite films with significantly larger grains and less defect density were prepared with the help of MAFa IL,and the corresponding device efficiency over 23%was obtained by two-step process with remarkably improved stability.This research work provides an efficient strategy to tune the morphology and opto-electronic properties of perovskite materials via ionic-liquid-assisted two-step fabrication method,which is beneficial for upscaling and application of perovskite photovoltaics.

A class of twostep continuity Runge-Kutta methods for solving singular delay differential equations and its convergence

An idea of relaxing the effect of delay when computing the Runge-Kutta stages in the current step and a class of two-step continuity Runge-Kutta methods （TSCRK） is presented. Their construction, their order conditions and their convergence are studied. The two-step continuity Runge-Kutta methods possess good numerical stability properties and higher stage-order, and keep the explicit process of computing the Runge-Kutta stages. The numerical experiments show that the TSCRK methods are efficient.

A Remarkable Chord Iterative Method for Roots of Uncertain Multiplicity

In this note we at first briefly review iterative methods for effectively approaching a root of an unknown multiplicity. We describe a first order, then a second order estimate for the multiplicity index m of the approached root. Next we present a second order, two-step method for iteratively nearing a root of an unknown multiplicity. Subsequently, we introduce a novel chord, or a two- step method, not requiring beforehand knowledge of the multiplicity index m of the sought root, nor requiring higher order derivatives of the equilibrium function, which is quadratically convergent for any , and then reverts to superlinear.

Explicit solutions to some nonlinear physical models by a two-step ansatz

Explicit solutions are derived for some nonlinear physical model equations by using a delicate way of two-step ansatz method.

General Convergence Analysis for Three-step Projection Methods and Applications to Variational Problems

First a general model for a three-step projection method is introduced, and second it has been applied to the approximation solvability of a system of nonlinear variational inequality problems in a Hilbert space setting. Let H be a real Hilbert space and K be a nonempty closed convex subset of H. For arbitrarily chosen initial points x0, y0, z0 ∈ K, compute sequences xn, yn, zn such thatT ： K→ H is a nonlinear mapping onto K. At last three-step models are applied to some variational inequality problems.

环丙沙星偶联物的制备及其产物的鉴定

采用碳二亚胺法,制备了环丙沙星-小牛血清蛋白偶联物,评价了pH、环丙沙星和碳二亚胺浓度对偶联结合比率的影响。同时采用红外光谱、紫外光谱、聚丙烯酰胺凝胶电泳和质谱方法对偶联产物的基团、分子量等特征进行分析鉴定。正交试验结果表明,pH对环丙沙星-小牛血清蛋白的偶联结合比率具有显著性差异,碳二亚胺和环丙沙星浓度差异性不显著。在pH5.0,碳二亚胺和环丙沙星浓度分别为60mg/mL和5mg/mL的条件下,环丙沙星-小牛血清蛋白偶联结合比率为30∶1。该方法条件下的偶联反应成功。结论:该方法可用于环丙沙星-小牛血清蛋白的偶联,且简便易行。

恩诺沙星完全抗原的制备试验

目的制备恩诺沙星(EF)的完全抗原,进而为EF单克隆抗体检测试剂盒的研制奠定基础。方法将小分子的药物EF和鸡血清白蛋白(OVA)以及牛血清白蛋白(BSA)分别采用碳二亚胺法和活化酯法两种不同的偶联方法合成完全抗原,通过紫外特征光谱和抗血清效价对完全抗原的合成效果进行分析。结果2种不同的偶联方法均使OVA和BSA与EF偶联成功。偶联方法对于完全抗原的合成效果也存在差异,从紫外吸光率和偶联物结合比判断,OVA采用活化酯法效果好,未经EDA处理的OVA、活化酯法和碳二亚胺法合成的偶联物的结合比分别为10.3、20.7、16.5;而BSA采用碳二亚胺法效果好,未经EDA处理的BSA、活化酯法和碳二亚胺法合成的偶联物的结合比分别为20.5、24.6和30.8。血清效价检测发现,以BSA-EF为完全抗原的效价为25600,以OVA-EF为完全抗原的效价为6400,这表明完全抗原的合成是成功的。结论2种不同方法合成的OVA-EF和BSA-EF完全抗原,可以作为免疫原用于制备抗体以及检测时的包被原进行ELISA检测。

氧氟沙星人工抗原的合成及鉴定

采用碳二亚胺法制备了氧氟沙星与牛血清白蛋白(BSA)及卵清蛋白(OVA)的结合物,通过FeCl3显色反应,紫外扫描以及动物免疫证明了人工抗原的成功合成。经紫外光谱法测定,每分子牛血清白蛋白连接的氧氟沙星分子数为11.16个;每分子卵清蛋白连接的氧氟沙星分子数为5.9个。

氯霉素全抗原的合成与鉴定

目的:为获得较高偶联率氯霉素全抗原,探索和优化碳二亚胺法(EDC)合成氯霉素(CAP)与牛血清白蛋白(BSA)全抗原合成条件。方法:采用单因素设计,优化影响合成的主要因素:蛋白浓度、CAP与BSA的摩尔比例、反应体系pH值,通过紫外法和三硝基苯磺酸(TNBS)法测定合成后的偶联率。结果:EDC法合成氯霉素全抗原较优条件为BSA浓度15mg/ml、CAP:BSA=70:1、pH7.4,可得到偶联率为15左右的氯霉素全抗原。结论:EDC法可用于制备较高偶联率的氯霉素全抗原,以用来进行抗体制备。

己烯雌酚免疫抗原的合成与鉴定

通过重氮化法引入羧基,再用碳二亚胺法偶联BSA获得己烯雌酚(DES)免疫抗原。经紫外光谱、电泳图谱分析确证获得DES-BSA偶联物。间接酶联免疫法分析证明其免疫鼠所获得的抗体与己烯雌酚有良好的特异性。

己烯雌酚免疫分析技术研究进展

己烯雌酚为人工合成的二苯乙烯类雌激素药物,曾经作为促生长剂广泛应用于畜牧业。但国内研究表明,己烯雌酚存在着潜在的致癌性。因此,近年来,其在饲料及动物性食品中的残留检测倍受关注,但己烯雌酚属于小分子化合物,不具备免疫原性。己烯雌激酚人工抗原主要采用混合酸酐反应(氯甲酸异丁酯法)将半抗原己烯雌酚与载体蛋白牛血清蛋白连接制备人工免疫原,并采用碳二亚胺法将半抗原己烯雌酚与载体蛋白卵清蛋白连接制备人工包被原。文章对己烯雌酚的免疫分析技术进行了综述。