Studies on the Construction Parameter of an Artificial Occluded Cell for In-situ Inspection of the Propagation Rate of Localized Corrosion

An artificial localized corrosion system is assembled and some parameters related to the localized corrosion in active dissolution state (i.e., non-passive state) have been studied. The results showed that the developed electrochemical system can satisfactorily imitate a naturally formed localized corrosion and the coupling current can indicate the maximum localized propagating rate. In this artificial system, the anodic dissolution reaction followed the auto-catalytic mechanism. The localized corrosion current density was dependent on the area ratio R of the cathode to the occluded anode. While R was equal to or more than 6, the coupling current reached at a maximum value and did not alter with the increase in R-value. Therefore, R=7 is chosen as one of these optimum parameters used in constructing the system, with which the biggest galvanic current might be obtained. In contrast, the thickness of the polymer filler separating the occluded anode area from the bulk electrolyte solution and the volume of the occluded anode area did not affect the corrosion current obviously. They might affect the response time to approach a steady state.

Detection of macular ganglion cell complex loss and correlation with choroidal thickness in chronic and recurrent central serous chorioretinopathy

AIM:To investigate the association of ganglion cell complex thickness(GCCt),global loss volume percentage(GLV%),and focal loss volume percentage(FLV%)with structural and functional findings among patients with chronic central serous chorioretinopathy(CCSC)and recurrent central serous chorioretinopathy(RCSC)by optical coherence tomography(OCT).METHODS:Among 29 patients with monocular affected central serous chorioretinopathy(CSC),15 had CCSC,and 14 had RCSC.The GCCt,FLV%,GLV%,and subfoveal choroidal thickness(SFCT)and sublesional choroidal thickness(SLCT)values were determined using OCT,and the association of these characteristics with neural structure parameters,choroidal morphology,features and functional alterations were estimated for the CCSC and RCSC patients.RESULTS:In CCSC,the affected eyes had significantly lower GCCt values than the fellow eyes in the macular regions(all P<0.05),with the highest GCCt observed in the inferior area.A significant association was found between the GCCt in different regions and the change in best corrected visual acuity(BCVA;r=-0.696;-0.695;-0.694,P<0.05)in CCSC patients.A statistically significant moderate negative correlation indicated that long-term CCSC was associated with greater differences in the GCCt in different regions between affected and fellow eyes(r=-0.562;r=-0.556;r=0.525,P<0.05).Additionally,observation of thickened SFCT was associated with a worse FLV%(r=0.599;r=0.546,P<0.05)in both groups.Similarly,thickened SLCT was associated with FLV%in RCSC patients(r=0.544,P<0.05).CONCLUSION:The distribution and GCCt are associated with the duration and visual outcomes of CCSC,whereas there is no correlation among RCSC patients.FLV%may be instrumental in differentiating the various outer choroidal vessels(pachyvessels)in long-term CSC.These results suggest that neural structure parameters may aid in estimating and predicting the recovery of altered morphology and function in CCSC and RCSC patients.

CHRONOABSORPTOMETRY FOR THE DETERMINATION OF KINETIC PARAMETERS OF ELECTRON TRANSFER REACTIONS USING LONG-OPTICAL-PATH ELECTROCHEMICAL CELL

A single potential step chronoabsorptometric method for the determination of ki- netic parameters of simple quasi-reversible reactions is described.It is verified by determining the kinetic parameters for the electroreduction of ferricyanide.A long-optical-path electro- chemical cell with a plug-in electrode is used.The thickness of solution layer is 0.55 mm

Experimental Evaluation of Parameterized Nonlinear MPC Applied to PEM Fuel Cell

This paper proposes a parameterized nonlinear model-based predictive control (NMPC) strategy to tackle the oxygen excess ratio regulation challenge of a proton exchange membrane fuel cell. In practice, the most challenging part regarding NMPC strategies remains the on-line implementation. In fact, NMPC strategies, at least in their basic form, involve heavy computation to solve the optimization problem. In this work, a specific parameterization of control actions has been designed to address this limitation and achieve on-line implementation. To assess the effectiveness and relevance of the proposed strategy, the controller has been implemented on-line, experimentally validated on a real fuel cell and compared to the built-in controller. Performance of the parameterized NMPC controller in terms of setpoint tracking accuracy, disturbances rejection and computational cost, have tested under several control scenarios. Experimental results have shown the excellent tracking capability, disturbances rejection ability and low computational cost of the NMPC controller, regardless of the operating conditions. Moreover, compared to the built-in controller the proposed strategy has demonstrated better disturbances rejection capability. Overall, the proposed parameterized NMPC controller appears as an excellent candidate to address the oxygen excess ratio regulation issue.

Effect of temperature on the efficiency of organometallic perovskite solar cells

In recent years perovskite solar cells have attracted an increasing scientific and technological interest in the scientific community. It is important to know that the temperature is one of the factors which have a strong effect on the efficiency of perovskite solar cell. This study communicates a temperature analysis on the pho- tovoltaic parameters of CH3NH3Pbl3-based perovskite solar cell in a broad interval from 80 to 360 K. Strong temperature-dependent photovoltaic effects have been observed in the type of solar cell, which could be mainly attributed to CH3NH3PbI3, showing a ferroelectric-paraelectric phase transition at low temperature （T 〈 160 K）. An increase in temperature over the room temperature decreased the perovskite solar cell performance and reduced its efficiency from 16Z to 9%. The investigation with electronic impedance spectroscopy reveals that at low temperature （T 〈 120 K） the charge transport layer limits the device performance, while at high temperature （T 〉 200 K）, the interfacial charge recombination becomes the dominant factor.

Correlations between trace elements in pyrite and gold mineralization of gold deposits on the North China platform

By studying both the microscopic physical and chemical typomorphic characteristics of typical mineral pyrite samples associated with representative gold deposits on the north-central margin of the North China Platform,this paper seeks to identify macroscopic metallogenic mechanisms of gold deposits and to reveal the formation mechanism of lattice gold in pyrite.Typomorphic characteristics of pyrite reveal that pyrite grain size has a negative correlation with gold content.Cubic pyrite,as the dominant crystal form,contains more gold than pentagonal dodecahedral pyrite.Both pyrite crystal forms and chemical compositions indicate that the replacement style of gold deposit formed in a low saturability,low sulfur fugacity,and at temperatures either much higher or much lower than its best forming temperature;comparatively,that of the quartz vein style of gold deposit occurred under conditions with the best temperature,rich in sulfur,and with high sulfur fugacity.The Au/Ag ratios of the pyrites show that both the replacement and quartz vein styles of deposits are mesothermal and hypothermal,while the Co/Ni ratios of the pyrites indicate that the quartz vein style is of magmatic-hydrothermal origin.The X-ray diffraction intensity of pyrite rich in gold is lower than that of pyrite poor in gold at the quartz vein style.In general,with an increase in gold content in pyrite,the total sum intensityΣI decreases.The pyroelectricity coefficient has a negative correlation trend with the values of(Co+Ni+Se+Te)-As and(Co+Ni+Se+Te)/As.The pyrite pyroelectricity of the replacement style is N-type,indicating that it formed under low sulfur fugacity,while that of the quartz vein style is a mixture of P-N types,indicating that it formed under high sulfur fugacity.On the pyroelectricity-temperature diagram,pyrite of the replacement style is mainly distributed between 200 and 270°C,while that of the quartz vein style varies between 90–118 and274–386°C,demonstrating a multistage forming process.In contrast to previous researchers'conclusions,the authors confirm the existence of lattice gold in pyrites through the use of an electron paramagnetic resonance(EPR)test.Au in the form of Au~+,entering pyrite as an isomorph and producing electron–hole centers,makes the centers produce spin resonance absorption and results in EPR absorption peak II.The intensity of auriferous pyrite absorption peak II has certain direct positive correlations with pyrite gold content.The#I and#III absorption peaks of pyrites possibly result from the existence of Ni^(2+)and/or Cu^(2+).γ1,γ2,andγ3 are the strongest and most typical absorption peaks of the infrared spectra of the pyrites.Generally,with the increase in gold content in the pyrite samples,γ1,γ2,andγ3 tend to shift to higher wavenumbers,and the gold content in the pyrite samples has a positive correlation with their relative absorbance.

PV Solar Yield Applicable Simulator Based on Free Irradiance Data Source:Applied Comprehensive Tool for Solar Engineers

Accurate PV system simulators are implemented with expensive software platforms using paid irradiance data.The main purpose of this paper is to develop and validate a PV system simulator,beginning with a solar cell parameter extraction model,then test and validate long-termIrradiance data using free online source(Typical Meteorological Year TMY in(PVGIS)European website),and finally building full solar generator simulator to run in working real conditions.Comparing results with Accurate Paid PV simulators(which use theMuneer model)showed good accuracy of the proposed simulator.Work flow starts with the Irradiance model’s data processing,then solar cell 5 parameters model data processing(to extract cell parameters),and finally full system simulator.MATLAB coding programs in real working conditions are used for simulation.Results of solar cell parameter extraction show 99.6%to 99.99%matching with data sheet and cell performance under standard test conditions.Systemmodel simulation output shows 8%less yearly generated energy compared to the PVGIS 2022 long-term simulation(hourly basis(one-year time)).This is due to incident energy variations(between the years 2016 and 2022)of 4.02%.The novelty of the algorithm is the methodology,as it tests irradiance data on an hourly basis and validates results for a whole continuous year.Also,the 5-parameter solar cell model is used to be validated in long term analysis,not only STC conditions and could be applied on any PV solar cell.The algorithm and block diagramused are scalable,modular,and interchangeable with similarmodels to be tested.This simulator could test severalmethods andmodels in solar pv technology.

基于增材制造的点阵结构优化

现有商业软件在构造拥有曲面边界轮廓的点阵结构时,会出现单胞破损现象,边界单胞破损的点阵结构不仅外观上有缺陷,而且力学性能较差,因此开发出一套大规模点阵结构的构造与优化设计方法非常具有理论价值和实际工程意义。首先,针对目前大规模点阵结构构造时存在的边界单胞破损问题,在有限元网格划分技术的基础上,提出了一种完整单胞的点阵结构构造方法;然后,将ANSYS的参数化语言APDL应用到具体的二维和三维实例中,并将该文提供的点阵结构与主流拓扑软件Inspire构造的点阵结构进行对比,结果表明基于有限元网格划分技术构造的点阵结构适应于不同的直线、曲线和曲面图形,较好地避免了几何图元边界处的单胞破损现象;最后,针对构造的含有完整单胞的均质点阵结构进行非均质优化,在MIST方法的基础上,提出了一种点阵结构杆件直径尺寸快速优化设计方法,分别应用到二维和三维仿真数值算例中,并选取合适的模型进行3D打印,通过点阵结构的压缩试验,进一步验证了非均质点阵结构优化设计方法的有效性。

三角网格参数化在反射地震走时层析成像中的应用

矩形网格参数化是反射地震走时层析成像中的传统参数化方式,然而这种参数化方式本身的缺点(如剖分的灵活性差,对速度界面的描述精度差)却在层析成像的正反演过程中产生了很多不利因素:正演模拟和层析反演时存储量大、计算量大、计算耗时久,层析反演的方程性态差、求解难度高等。鉴于矩形网格参数化层析成像的上述缺点,将三角网格参数化应用到反射地震走时层析成像中,研究发现三角网格参数化本身的优点(如剖分的灵活性强,对速度界面的描述精度高)在层析成像的正反演过程中产生了诸多有利因素,大大减少了网格的数目,在正演模拟和层析反演时大大减少了存储量、计算量和计算时间,并改善了层析反演的方程性态,降低了求解难度。因此,三角网格参数化与矩形网格参数化相比在反射地震走时层析成像中更有优越性,模型试验表明两种参数化方式得到的层析反演结果具有可比性。

解析法-Nelder Mead单纯形算法确定太阳电池参数

光伏发电系统的设计计算、性能评估及优化控制要求快速、准确的确定太阳电池模型参数。针对太阳电池单、双二极管模型参数辨识问题,该文提出一种基于解析法和Nelder Mead单纯形法重启策略的A-bcNM混合算法。先用实测I-V曲线上的部分关键点计算合成参数,再以单二极管模型近似解析式快速定位搜索始点,最后在边界范围内利用Nelder Mead单纯形算法的重启策略最小化实测数据与模拟结果之间的均方根误差,以提高拟合精度及参数解的质量。MATLAB环境下,利用2种典型太阳电池的实测数据对A-bcNM算法的有效性进行了测试和验证。与已有的其他算法相比,A-bcNM算法收敛速度快,计算量小,辨识精度高,可快速、准确的确定单、双二极管模型参数,为识别太阳电池的工作特性提供了一种有效方法。

燃料电池车用离心叶轮型线参数化及多工况优化

以65kW燃料电池动力系统的高速无油润滑离心空压机为优化对象,采用Bezier曲线对其叶片型线进行参数化解析,依据超拉丁抽样方法获得遗传算法优化所需的样本空间,在此基础上建立Kigring近似模型进行多工况优化.寻优及CFD(计算流体动力学)数值计算结果显示,常用工况点和额定工况点等熵效率及压比均得到提高,且常用工况点改善更为显著.这表明传统内燃机车用离心增压器设计及优化时不能兼顾多工况性能结论不适用燃料电池汽车,叶轮性能空气动力学解析同样证实该结论具有理论基础.与基于叶轮几何参数的优化结果对比显示,基于叶片型线参数化的优化可以更加显著地改善离心空压机性能,是一种更加全面和有效的离心叶轮优化方法.

基于CAD平台的周期性材料单胞的参数化形状优化设计方法

对于具有特定材料属性的周期性复合材料设计,提出了一种参数化的形状优化方法。对于带有周期性结构的两相材料,给定细观单胞结构的基本构型,通过参数化的实体造型技术,结合均匀化方法,实现了通用的材料单胞形状参数化设计方法,以获取指定材料性能。在参数化结构形状优化设计CAD/CAE集成平台POSHAPE上完成程序实现。文中算例给出了两相蜂窝型骨架复合材料和空心复合材料周期性单胞的零泊松比和指定参数性质的形状优化设计过程,并验证了本文方法的有效性。

Studies on the Structure and Properties of Cordierite Synthesized by Talc-Magnesite

Homogeneous cordierite has been synthesized at low cost by talc-magnesite and coal gangue as the main raw materials. The mechanism of synthesizing cordierite under such a composing system of raw materials, and the effect of temperature on the crystal cell parameters and microstructure and thermal expansion coefficient of cordierite crystal have been studied via testing methods of XRD, SEM, etc. The result shows that the homogeneous cordierite can be synthesized by the systematic composing materials of ＂talc-magnesite-coal gangue-talc＂ with heat pre-servation at 1350 ℃ for 1 h; as the keeping time is prolonged, Al^3＋ and Mg^2＋ in cordierite crystal are replaced by a few impurity ions such as Fe^3＋, Fe^2＋, etc., and the crystal cell parameters of cordierite present an increase trend; as the high-temperature heat preservation is prolonged, the content of glassy phase in the sample is increased, its density is improved, and its thermal expansion coefficient presents an increase trend.

Influence of Fe_2O_3 and V_2O_5 on Crystalline Structure of Mg-Al Spinel Synthesized by Waste Aluminum Slag

Mg-Al spinel is synthesized by using industrial waste-residue and basic magnesium carbonate in the aluminum factory as the main raw materials. The influence of V2O5 and Fe2O3 mineralizers on the structure, cell parameters and microscopic morphology of synthesized Mg-Al spinel has been discussed. The Mg-Al spinel is characterized by using XRD, SEM and relevant analytical software, such as Philips plus, Rietveld quantification and so on. The experimental results show that certain amounts of V2O5 and Fe2O3 are beneficial to the formation of Mg-Al spinel, and the optimum addition of V2O5 and Fe2O3 is respectively 2wt% and 3wt%. V2O5 has few effects on cell parameters of Mg-Al spinel; but Fe2O3 can form solid solution with Mg-Al spinel in which Mg-Fe spinel can also dissolve to form continuous solid solution. Therefore, with the increase of Fe2O3 content, the cell parameters of Mg-Al approximately present linear increase.

三维五向及全五向编织复合材料的三单胞结构模型

针对三维五向及全五向编织复合材料,基于四步法编织工艺携纱器的运动规律,研究了各单胞区域纱线的运动轨迹和空间走向,给出了材料内胞、面胞和角胞的纱线拓扑结构。通过给定一系列的位置节点和节点间线性插值函数的方法来描述纱线空间轨迹。考虑纱线间的相互挤压状况,在假设编织纱和轴纱横截面形状分别为扁平椭圆形和正方形的基础上,系统建立了三维五向及全五向编织复合材料的三单胞参数化结构模型。给出了两种编织材料的纤维体积含量计算公式并进行了对比分析,明确了三维全五向编织复合材料的轴向性能优势。分析了三维五向编织材料的表面多胞结构及三维全五向编织材料的内胞截面图,并与实际试件结构进行对比,结果表明本文所建模型合理准确。

Chemical and physical characteristics of quartz from gold deposits in the North China platform: relationship to gold mineralization

This paper seeks to identify macroscopic metallogenic mechanisms of various mineral deposits by studying microscopic typomorphic characteristics of typical minerals associated with the deposits and to reveal the mechanism of lattice gold in detail by studying both physical and chemical characteristics of quartz from representative gold deposits in the North China Platform.As part of their extensive research,the authors examine the relationship between trace elements with wall rock,the ore-forming media,and gold immigration of various types of gold deposits,including their salinity,type,temperature.These are key factors to revealing the mineralization mechanism,and indicators for mineral prospecting,exploration,mining,and metallurgical technology.In order to address the questions posed,the following methods were used:field investigations of geology and sampling of the representative gold deposits,physical study and chemical analysis of quartz including,but not limited to,fluid inclusions as well as their compositions and trace elements in quartz,the unit cell parameters,electron paramagnetic resonance spectrum(EPR),and infrared spectroscopic analysis(ISA).As a result of this study,the authors observe the following key findings:unit cell parameters of quartz vary with their contents of foreign elements including gold,paragenetic stage,wall rock type,and other factors;the higher the forming temperature and the lower the gold content in quartz,the smaller the unit cell parameters,and vice versa.Additionally,the EPR absorption lines resulted from the O–Al defect center.The density of these types of hole centers increases and the EPR signal strengthens when the temperature decreases.Based on the findings,the authors conclude that lattice gold exists in quartz.Gold,in the form of Au^(+)and/or Au^(3+),entering quartz and producing an electron–hole center,namely,the O-Au hole center,makes the center produce spin resonance absorption and results in the EPR absorption peak#I.Both unit cell parameters and EPR of quartz can potentially be used in mineral prospecting,relative ore-forming temperature determination,and grade control during mining.

Influence of Cr_2O_3 on the Structure and Property of Mg-Al Spinel Synthesized by Waste Slag in Aluminum Factory

Via the solid phase reaction, Mg-Al spinel has been synthesized by using industrial waste slag from aluminum factory, basic magnesium carbonate and a little amount of clay as the main raw materials. The influences of Cr2O3 mineralizer on crystalline structure, micro-morphology and properties of synthesized Mg-Al spinel are discussed. The synthesized product was characterized by using XRD and SEM, and the relative contents of each crystalline phase are calculated by relevant analytical software such as Philips plus, Rietveld quantification and so on. The experimental results show that a certain amount of Cr2O3 is helpful to the formation of Mg-Al spinel, and when the addition of Cr2O3 is 2.0%, Mg-Al spinel in the system exists in the form of solid solution （Mg0.68A10.32）（A10.84Mg0.16）2O4 whose content is the highest reaching 91%. Then the corresponding indexes of each property are as follows： water absorption 3.0%, apparent porosity 9.8%, bulk density 3.36 g·cm^3, and flexural strength 83.32 MPa. Therefore, we can confirm that the optimum addition of Cr2O3 mineralizer is 2.0%.

三维编织预制件单胞模型的参数化

应用Pro/E的3D实体建模功能建立了三维整体编织预制件的单胞模型,包括内部单胞、表面单胞和棱角单胞。模型中真实反映了纤维尺寸和纱线走向。基于编织工艺参数间的关系,在Pro/E中实现了参数化设计,不同编织角下的各种单胞模型可自动生成。作为三维编织预制件中的周期排列微观结构,参数化单胞的建立为进一步研究三维整体编织复合材料的性能提供了便于应用的理论分析模型。

Pedogenically degenerated illite and chlorite lattices aid to palaeoclimatic reconstruction for chronologically constrained(8-130 ka) loess-palaeosols of Dilpur Formation,Kashmir,India

Chronologically well-constrained loess-palaeosols(recorded glacial and inter-glacial climate) revealed pedogenesis induced ionic substitutions,caused end-member compositional deviations in illite and chlorite,linked to widespread climatic changes occurred during Late Pleistocene.Further,micro-level climatic resolution is yet to be resolved.Thus,layer-wise X-ray diffraction analyses of clay separates,followed by Rietveld refinement revealed varied cell parameters and interatomic distances.Obtained values for detrital and pedogenic illite and chlorite when plotted against stratigraphic succession show notable changes in the crystallographic axes.The illite lattices associated with inadequately pedogenized palaeosols have been altered into illite/smectite mixed layers,but,the chlorite lattices represent expansion of a-,b-and contraction of c-axes with much greater amount of distortions,suggestive of warm-humid and acidic environment.The detrital 48,44 and 83,74 bonded illite and chlorite with2 sub-types each,when pedogenized retained 48,44 and 34;and 83 and 74 bonds(in their neo-formed 3 and 2 sub-types),respectively.The Al-O bond shows expansion,but,unchanged Si-O and decreased Si-K and K-O bonds show loss of Al and retention of Si and K ions in the illite lattices.The illite with 32 atoms and 48 bonds represent contraction of K-O,Si-K,Al-O and Si-O bonds caused bond reinforcement;however,loss of Al3+reflects all-out illite alteration.Owing to Al-O and K-O bond expansion,major K+ and Al3+ ionic loss occurred during the LGM,however,further ionic loss depends upon the magnitude of the loess-palaeosol weathering that they have suffered.The clilate sensitive Fe,Mg and Al ionic losses for Fe-O,Mg-O and Al11-O9 bond length expansions were recognized in the chlorite lattices.Such ionic losses are common,but,complete distortion is attributed to Al,Si,Fe and Mg ionic losses,followed by weakening of Al-O,Si-O,Fe-O and Mg-O bonds.Though,Si-O4 and Fe1-O4 bonds,and Si and Fe1 st ions remain intact.Thus,three major glacial episodes of ~5 ka each occurred under alkaline environment,but,intervened by two successive cycles of 55 ka each,encompassing three alternate warm and cold climatic sub-cycles of 12-15 ka.But,the coldness increases with each warm-cold sub-cycle that attained the glacial maxima.Further,these events correlate well with the deep-sea records of the North Atlantic(MIS-1 to MIS-5 e) and CLP loess-palaeosols(~127 ka).

Isomorphous Substitution of Metallic Elements for Zeolite Y in the Aqueous Solution

The substitutions of Ti, Fe and Zr into zeolite Y in the aqueous solutions of (NH4)2TiF6, (NH4)3ZrF7 and (NH4)3FeF6 were systematically Investigated. It was found that Ai atoms in the framework can be replaced by some metallic elements and the extent of substitution depends on the M/A1 ratio of the solution. The maximum allowable M/A1 ratio of the aqueous solution Is related with the radius of the M atom and the stability constant of the MFnm- complex. The substituted zeolite samples with crystallinity greater than 80% were characterized by means of XRD, IR, DTA, TPR and NH3-TPD measurements. The incorporation of Ti, Fe and Zr into the zeolite leads to an increase in the unit cell parameter, a lowering of thermal stability and a red shift of the asymmetric stretching frequency. The extent of these changes is apparently related with the ionic radius of the metallic element and the degree of substitution. The results of various characterization methods show that the het-eroatoms are readily Introduced into the zeolite framework by this preparation method. It was also observed that the substitution of heteroatoms may strengthen or weaken the surface acidity of zeolite Y.