Maskless fabrication of quasi-omnidirectional V-groove solar cells using an alkaline solution-based method

Silicon passivated emitter and rear contact(PERC) solar cells with V-groove texture were fabricated using maskless alkaline solution etching with in-house developed additive. Compared with the traditional pyramid texture, the V-groove texture possesses superior effective minority carrier lifetime, enhanced p–n junction quality and better applied filling factor(FF). In addition, a V-groove texture can greatly reduce the shading area and edge damage of front Ag electrodes when the V-groove direction is parallel to the gridline electrodes. Due to these factors, the V-groove solar cells have a higher efficiency(21.78%) than pyramid solar cells(21.62%). Interestingly, external quantum efficiency(EQE) and reflectance of the V-groove solar cells exhibit a slight decrease when the incident light angle(θ) is increased from 0° to 75°, which confirms the excellent quasi omnidirectionality of the V-groove solar cells. The proposed V-groove solar cell design shows a 2.84% relative enhancement of energy output over traditional pyramid solar cells.

Static-to-kinematic modeling and experimental validation of tendon-driven quasi continuum manipulators with nonconstant subsegment stiffness

Continuum robots with high flexibility and compliance have the capability to operate in confined and cluttered environments. To enhance the load capacity while maintaining robot dexterity, we propose a novel non-constant subsegment stiffness structure for tendon-driven quasi continuum robots(TDQCRs) comprising rigid-flexible coupling subsegments.Aiming at real-time control applications, we present a novel static-to-kinematic modeling approach to gain a comprehensive understanding of the TDQCR model. The analytical subsegment-based kinematics for the multisection manipulator is derived based on screw theory and product of exponentials formula, and the static model considering gravity loading,actuation loading, and robot constitutive laws is established. Additionally, the effect of tension attenuation caused by routing channel friction is considered in the robot statics, resulting in improved model accuracy. The root-mean-square error between the outputs of the static model and the experimental system is less than 1.63% of the arm length(0.5 m). By employing the proposed static model, a mapping of bending angles between the configuration space and the subsegment space is established. Furthermore, motion control experiments are conducted on our TDQCR system, and the results demonstrate the effectiveness of the static-to-kinematic model.

Study of damage behavior and repair effectiveness of patch repaired carbon fiber laminate under quasi-static indentation loading

Damage caused due to low-velocity impacts in composites leads to substantial deterioration in their residual strength and eventually provokes structural failure.This work presents an experimental investigation on the effects of different patch and parent laminate stacking sequences on the enhancement of impact strength of Carbon Fiber Reinforced Polymers(CFRP)composites by utilising the adhesively bonded external patch repair technique.Damage evolution study is also performed with the aid of Acoustic Emission(AE).Two different quasi-isotropic configurations were selected for the parent laminate,viz.,[45°/45°/0°/0°]s and[45°/0°/45°/0°]s.Quasi Static Indentation(QSI)test was performed on both the pristine laminates,and damage areas were detected by using the C-scan inspection technique.Damaged laminates were repaired by using a single-sided patch of two different configurations,viz.,[45°/45°/45°/45°]and[45°/0°/0°/45°],and employing a circular plug to fill the damaged hole.Four different combinations of repaired laminates with two configurations of each parent and patch laminate were produced,which were further subjected to the QSI test.The results reveal the effectiveness of the repair method,as all the repaired laminates show higher impact resistance compared to the respective pristine laminates.Patches of[45°/0°/0°/45°]configuration when repaired by taking[45°/45°/0°/0°]s and[45°/0°/45°/0°]s as parents exhibited 68%and 73%higher peak loads,respectively,than the respective pristine laminates.Furthermore,parent and patch of configuration[45°/0°/45°/0°]s and[45°/0°/0°/45°],respectively,attain the highest peak load,whereas[45°/45°/0°/0°]s and[45°/45°/45°/45°]combinations possess the most gradual decrease in the load.

On the Equality of Weighted BajratarevićMeans to Quasi-Arithmetic Means

In this paper, we considered the equality problem of weighted Bajraktarević means with weighted quasi-arithmetic means. Using the method of substituting for functions, we first transform the equality problem into solving an equivalent functional equation. We obtain the necessary and sufficient conditions for the equality equation.

The Maximum and Minimum Value of Exponential RandićIndices of Quasi-Tree Graph

The exponential Randić index has important applications in the fields of biology and chemistry. The exponential Randić index of a graph G is defined as the sum of the weights e 1 d( u )d( v ) of all edges uv of G, where d( u ) denotes the degree of a vertex u in G. The paper mainly provides the upper and lower bounds of the exponential Randić index in quasi-tree graphs, and characterizes the extremal graphs when the bounds are achieved.

Fuzzy Henstock-Kurzweil Triple Integral on a Type 1 Quasi-Fuzzy Parallelepipedal Domain

In this article, we propose by using the Hausdorff distance Simpson’s rule for the triple integral of a fuzzy-valued function and the error bound of this method, one of the variables of which is fuzzy. In addition, thin δ-fine partitions are introduced. The integration domain is a quasi-fuzzy parallelipiped. A numerical example is presented in order to show the application and the significance of the method.

Crank-Nicolson Quasi-Compact Scheme for the Nonlinear Two-Sided Spatial Fractional Advection-Diffusion Equations

The higher-order numerical scheme of nonlinear advection-diffusion equations is studied in this article, where the space fractional derivatives are evaluated by using weighted and shifted Grünwald difference operators and combining the compact technique, in the time direction is discretized by the Crank-Nicolson method. Through the energy method, the stability and convergence of the numerical scheme in the sense of L2-norm are proved, and the convergence order is . Some examples are given to show that our numerical scheme is effective.

一种适用于大幅值Quasi周期轨道的数值构造方法

针对现有方法在构造大幅值quasi周期轨道时收敛性和通用性不足等问题,提出一种适用于大幅值quasi周期轨道的数值构造方法。首先针对2维不变环面的计算问题,设计了映射间隔约束的环面多步微分修正算法。在此基础上,采用自然参数延拓法和伪弧长延拓法两种不同的思路构造等映射间隔的quasi周期轨道族。接着以quasi-Vertical为对象分析了两种思路各自的特点。最后以quasi-Axial,quasi-DRO等为对象验证了方法对三角平动点及多对复特征值情况的适用性。仿真结果表明,所提出的方法能够简单有效地解决多种类型幅值比超过1.2的大幅值quasi周期轨道的数值计算问题。

基于变分节块法六角形Quasi-diffusion程序开发及验证

传统扩散理论在中子各向异性强的堆芯计算中具有较低的精度,Quasi-diffusion方程相比于传统扩散方程引入更少的近似,通过艾丁顿因子描述传统扩散理论不能反映的中子流各向异性特点。国内外对六角形几何三维Quasi-diffusion方程研究有所不足。针对艾丁顿因子计算的非线性特点,本文基于“两步法”的思想,将艾丁顿因子看作是一个特殊的少群参数,采用中子能谱适应性更好的蒙特卡罗程序SERPENT计算,并对传统扩散变分节块法进行拓展,开发了六角形组件堆芯计算程序VNMQD。采用3D VVER1000基准题、RBWR单组件问题、3D BN600简化模型对程序进行了验证,结果表明:VNMQD程序开发正确,对于非均匀性较强的堆芯,VNMQD比传统扩散方法计算精度更高、计算效率接近,实现了计算精度和计算效率的平衡。

Solute drag-controlled grain growth in magnesium investigated by quasi in-situ orientation mapping and level-set simulations

Critical properties of metallic materials,such as the yield stress,corrosion resistance and ductility depend on the microstructure and its grain size and size distribution.Solute atoms that favorably segregate to grain boundaries produce a pinning atmosphere that exerts a drag pressure on the boundary motion,which strongly affects the grain growth behavior during annealing.In the current work,the characteristics of grain growth in an annealed Mg-1 wt.%Mn-1 wt.%Nd magnesium alloy were investigated by advanced experimental and modeling techniques.Systematic quasi in-situ orientation mappings with a scanning electron microscope were performed to track the evolution of local and global microstructural characteristics as a function of annealing time.Solute segregation at targeted grain boundaries was measured using three-dimensional atom probe tomography.Level-set computer simulations were carried with different setups of driving forces to explore their contribution to the microstructure development with and without solute drag.The results showed that the favorable growth advantage for some grains leading to a transient stage of abnormal grain growth is controlled by several drivers with varying importance at different stages of annealing.For longer annealing times,residual dislocation density gradients between large and smaller grains are no longer important,which leads to microstructure stability due to predominant solute drag.Local fluctuations in residual dislocation energy and solute concentration near grain boundaries cause different boundary segments to migrate at different rates,which affects the average growth rate of large grains and their evolved shape.

Quasi Controlled K-Metric Spaces over C^(*)-Algebras with an Application to Stochastic Integral Equations

Generally,the field of fixed point theory has attracted the attention of researchers in different fields of science and engineering due to its use in proving the existence and uniqueness of solutions of real-world dynamic models.C^(∗)-algebra is being continually used to explain a physical system in quantum field theory and statistical mechanics and has subsequently become an important area of research.The concept of a C^(∗)-algebra-valued metric space was introduced in 2014 to generalize the concept of metric space.In fact,It is a generalization by replacing the set of real numbers with a C^(∗)-algebra.After that,this line of research continued,where several fixed point results have been obtained in the framework of C^(∗)-algebra valued metric,aswell as(more general)C^(∗)-algebra-valued b-metric spaces andC^(∗)-algebra-valued extended b-metric spaces.Very recently,based on the concept and properties of C^(∗)-algebras,we have studied the quasi-case of such spaces to give a more general notion of relaxing the triangular inequality in the asymmetric case.In this paper,we first introduce the concept of C^(∗)-algebra-valued quasi-controlledK-metric spaces and prove some fixed point theorems that remain valid in this setting.To support our main results,we also furnish some exampleswhichdemonstrate theutility of ourmainresult.Finally,as an application,we useour results to prove the existence and uniqueness of the solution to a nonlinear stochastic integral equation.

基于Quasi-Z源逆变器的光伏并网系统模型预测控制

为了克服传统并网逆变器不能兼具升降压变换的功能以及死区引起的输出波形畸变等问题,设计一种基于Quasi⁃Z源逆变器的光伏并网系统。提出一种改进的有限集模型预测控制策略来控制并网Quasi⁃Z源逆变器的直流升压电压和交流输出电流,更好的调节输出波形的质量、提升系统的动态性能和稳定性。在所设计的系统中,依据测得的Quasi⁃Z源逆变器的电容电压和交流负载电流的值,再对电容器电压和输出交流的数值进行预测。在确定qZSI可能产生的每一个电压矢量之后,将其用以跟踪电容电压和输出电流参考值。从而在单级逆变器中实现光伏发电的最大功率点跟踪和单位功率因数并网,在光照强度阶跃变化时,仿真结果表明系统具有优良的动态响应性能。结果验证了所采用的系统结构和算法的有效性和可行性。

强Quasinil Quasi-clean环和Quasi-polar环

设R是一个环,称环R的元素e为拟幂等元,如果存在R的某个中心单位k,使得e 2=ke。若R中的每个元素都存在拟幂等元e∈R,q∈R qnil使得e∈comm 2(a),并且a=e+q,则称环R是强quasinil quasi-clean环。若环R中每个元素a都存在一个拟幂等元e∈R使得e∈comm 2(a),a+e∈U(R)且ae∈R qnil,则称R是拟quasi-polar环。本文首先证明拟quasi-polar环与quasi-polar环等价,在此基础上进一步证明强nil quasi-clean环是强quasinil quasi-clean环,强quasinil quasi-clean环是quasi-polar环,但反之均不成立。

California Bearing Ratio for Cohesive Soils from Quasi Static Cone Tests

The California bearing ratio (CBR) test is the most widely spread method of determining the bearing strength of the pavement material and is fundamental to pavement design practice in most countries. This test is expensive, laborious and time consuming, and to overcome this, Quasi static cone penetrometer machine was fabricated and used to measure the consistency limits (liquid limit-LL, Plastic limit-PL and Plasticity index-PI), which were used to develop an empirical equation to determine CBR. Soil samples were collected and unsoaked CBR, PL, LL and PI were determined according to BS 1377 part 9 and BS 1377-2;1990. Quasi static penetration forces at 20 mm depth of penetration were also determined at consistency limits. It was found that the force of 1020 gf and 60 gf was achieved at a depth of 20 mm at PI and LL respectively. The correlation and regression analysis between consistency limits, and the experimental CBR obtained showed coefficient of determination, R2 = 0.907 between CBR and all the parameters using multiple linear regression analysis (MLRA). The regression equation developed was used together with the relationship developed between the Quasi static Penetration force at consistency limits and the tested consistency limits to come up with the General Empirical Equation. Verification of the formula showed that the correlation can be used accurately to determine the un soaked CBR.

热轧含钛低合金高强钢板断口分层机理研究

利用光学显微镜(OM)、电子背散射衍射仪(EBSD)、透射电镜(TEM)等设备研究了含钛低合金高强钢拉伸断口分层原因。结果显示:在显微组织和晶粒尺寸正常的情况下,MnS和大颗粒Ti(C,N)夹杂物聚集是导致断口分层的根本原因。拉伸断口呈现撕裂棱+浅韧窝的准解理形貌。塑性变形过程中,Ti(C,N)破碎导致显微裂纹萌生。裂纹沿着薄膜状MnS传导,最终在MnS和基体界面形成撕裂棱。大量平行分布的MnS夹杂物共同作用,使断口产生分层现象。通过降低S、N含量能够有效减少两类夹杂物数量,消除断口分层现象,改善塑性指标。

强J-quasi-clean环

该文引入了强J-quasi-clean环,并证明了强J-clean环是强J-quasi-clean环,而强J-quasi-clean环是强拟clean环,反过来都是不成立的;还证明了环R是强J-quasi-clean的当且仅当R/J(R)是拟Boole环且其每个拟幂等元都能强提升;最后指出强J-quasi-clean环是左(右)quasi-duo环.

仿猫类落地姿态的准零刚度隔振器

对设备加装隔振装置是保证其高效工作的重要方法之一.本文从仿生学的角度,根据猫科动物落地时优秀的抗冲击能力,通过观察其落地动作姿态,利用非线性补偿原理,以空气弹簧作为正刚度结构,设计出一种具有非对称刚度特性的高静低动刚度隔振器.以其为研究对象,建立了动力学模型,利用特定的方法对非对称刚度系统进行分析求解,并与数值结果和有限元仿真结果进行对比.结果表明,在较低阻尼以及较高激励幅值下,还会出现倍周期响应甚至混沌响应.同时,通过将本文设计的隔振结构和单一空气弹簧的隔振性能对比,可以得到隔振效果明显优于单一空气弹簧的结论,从而验证了所设计隔振结构的有效性和可行性.

Impacts of the stratospheric quasi-biennial oscillation on the tropospheric circulation and climate in the Northeast Asia-North Pacific region in early summer

本文研究了平流层准两年振荡(QBO)对东北亚-北太平洋地区初夏对流层环流和地表气温的影响.在QBO西风位相年,东北亚至北太平洋地区存在一支由QBO引发的平均经向环流异常,该经向环流异常可在东北亚至北太平洋地区激发正涡度,并形成异常气旋式环流.气旋左侧出现的异常偏北风导致6月东北亚地表气温下降.QBO东风位相年的结果与西风位相年大致相反.这些结果为QBO对热带外地区天气,气候的影响提供了新的证据,并为东北亚初夏地表气温的预测提供了新的线索。

A Quasi-Experimental Study of English Vocabulary Teaching Based on Incidental Acquisition

Recent years have witnessed a phenomenon that major English teachers in China have adopted the traditional teaching pattern, mechanically linking English pronunciations directly with the meaning of Chinese, which gradually dampens learners’ enthusiasm. The chief purpose of this paper was to design one English vocabulary teaching lesson based on incidental acquisition. More specifically, the questions raised are, on the one hand, whether incidental vocabulary teaching imprints differences on the learning outcomes for middle school students, and, on the other hand, whether incidental acquisition results in positive feedback between teachers and students. The technique we applied was referred to as questionnaires and interviews addressed to a sample of 68 students. Focusing on the effect of incidental vocabulary acquisition, the analysis demonstrated that it could enhance students’ vocabulary capacity. In addition, it was interesting to note that excellent students and average students tended to embrace the new teaching style while underachievers were on the opposite side. On this basis, it is recommended for English teachers to design English vocabulary lessons, adopting visual, auditory, oral, reading or writing training. More precisely, they should use phonics rules and patterns, holistic learning, classified vocabulary teaching, visual illustration or multimedia teaching to give lessons effectively and expand learners’ vocabulary.

Lower Bounds of Decay Rates for Solution to the Single-Layer Quasi-Geostrophic Model

In this paper, we study the long-time behavior of solutions of the single-layer quasi-geostrophic model arising from geophysical fluid dynamics. We obtain the lower bound of the decay estimate of the solution. Utilizing the Fourier splitting method, under suitable assumptions on the initial data, for any multi-index α, we show that the solution Ψ satisfies .