Solvent engineering towards scalable fabrication of high-quality perovskite films for efficient solar modules

Over the last decade,remarkable progress has been made in metal halide perovskite solar cells(PSCs),which have been a focus of emerging photovoltaic techniques and show great potential for commercialization.However,the upscaling of small-area PSCs to large-area solar modules to meet the demands of practical applications remains a significant challenge.The scalable production of high-quality perovskite films by a simple,reproducible process is crucial for resolving this issue.Furthermore,the crystallization behavior in the solution-processed fabrication of perovskite films can be strongly influenced by the physicochemical properties of the precursor inks,which are significantly affected by the employed solvents and their interactions with the solutes.Thus,a comprehensive understanding of solvent engineering for fabricating perovskite films over large areas is urgently required.In this paper,we first analyze the role of solvents in the solution-processed fabrication of large-area perovskite films based on the classical crystal nucleation and growth mechanism.Recent efforts in solvent engineering to improve the quality of perovskite films for solar modules are discussed.Finally,the basic principles and future challenges of solvent system design for scalable fabrication of high-quality perovskite films for efficient solar modules are proposed.

A Review of Nano/Micro/Milli Needles Fabrications for Biomedical Engineering

Needles,as some of the most widely used medical devices,have been effectively applied in human disease prevention,diagnosis,treatment,and rehabilitation.Thin 1D needle can easily penetrate cells/organs by generating highly localized stress with their sharp tips to achieve bioliquid sampling,biosensing,drug delivery,surgery,and other such applications.In this review,we provide an overview of multiscale needle fabrication techniques and their biomedical applications.Needles are classified as nanoneedles,microneedles and millineedles based on the needle diameter,and their fabrication techniques are highlighted.Nanoneedles bridge the inside and outside of cells,achieving intracellular electrical recording,biochemical sensing,and drug delivery.Microneedles penetrate the stratum corneum layer to detect biomarkers/bioelectricity in interstitial fluid and deliver drugs through the skin into the human circulatory system.Millineedles,including puncture,syringe,acupuncture and suture needles,are presented.Finally,conclusions and future perspectives for next-generation nano/micro/milli needles are discussed.

Analysis of Various Types Engineering Stripe Knit Fabrics of Bangladeshi Knit Industry

This experiment is generally based on the three types of engineering stripe fabrics named single jersey, full feeder lycra single jersey, and single lacoste fabric. In Bangladesh, conventional practices of engineering stripe fabric hardly seen. As the textile engineer, we focused to identify the basic difference between these fabrics. We kept the repeat length constant for all three fabrics. In these circumstances, how stitch length, yarn count, gsm, fabric dia, machine settings, machine maintenance, machine rpm varies into those three mentioned fabrics. It is the main motto of these experiments to make them more favourable into the trendy fashion world.

New Theoretical Aspects of Software Engineering for Development Applications and E-Learning

This paper presents new theoretical aspects of software engineering which oriented on product lines for building applied systems and software product families from readymade reusable components in conditions of program factories. These aspects are the new disciplines such as the theory of component programming;models variability and interoperability of system;theory for building systems and product families from components. Principles and methods of implementing these theories were realized in the instrumental and technological complex by lines of component development: assembling program factories using lines, e-learning to new theories and technologies in textbook of “Software Engineering” by the universities students.

Fabrication of Porous Scaffolds Using NaHCO_3 Particulates as the Porogen Material

A new method of fabricating porous polymer scaffolds was developed, using sodium hydrogen carbonate particulates as the porogen to foam. The pore structure of polymer scaffolds can easily be manipulated by controlling the size and weight fraction of sodium hydrogen carbonate particulates. The scaffolds are highly porous with a porosity greater than 90% and with a larger pore size ranging from 100-400μm, and are well distributed with the interconnected and open pore wall structure which is necessary for tissue engineering. We investigated the effect of the porosity of scaffolds, the pore size of scaffolds and material of polymer on the mechanical properties of scaffolds. The scaffolds fabricated by the method have more big pores than those by the convenient method of salt leaching.

Rapid Prototyping Technology of Tissue Engineering Scaffold

In the modern medicine field, the transplant of organ and tissue is a big problem due to serious shortage of donor organ. Artificial organ and tissue is one of solutions. With the development of science, various tissue manufacture techniques emerged. Hereinto, due to its versatility both in materials and structure, rapid prototyping technology has become one of the important methods for tissue engineering scaffold fabrication in this field.

Fabric characteristics of in situ sand with/without liquefaction verified by anisotropy of magnetic susceptibility

It is well known that fabric of sand may significantly affect mechanical behaviors and liquefaction resistance of sand.Various optical techniques are currently utilized to visualize the fabric,especially the distribution of the long axis of soil particles.However,none of these methods provides an ideal solution in laboratory tests and in situ observation.In this study,anisotropy of magnetic susceptibility(AMS)was first proposed as a convenient and efficient way to evaluate the liquefaction of clean sand.At first,investigations with scanning electron microscopy(SEM)and AMS were simultaneously conducted on two groups of soil specimens with different initial fabrics to verify the feasibility of the AMS technique.Then,80 in situ samples were collected to analyze the feature of liquefied and non-liquefied sand layers through AMS tests.It is clearly known from the test results that the natural sedimentary fabric was destroyed during liquefaction and the fabric anisotropy was greatly changed after liquefaction.The feasibility of evaluating soil fabric using the AMS survey was verified by the laboratory tests.Furthermore,the applicability of AMS in detecting liquefied layer in situ was confirmed for the first time.

玄武岩织物-钢-PVA工程水泥基复合材料单轴受压力学性能研究

本文研究了玄武岩织物和混杂短切纤维(钢纤维及PVA纤维,短切纤维总体积掺量为2%)复合作用对玄武岩织物-钢-PVA工程水泥基复合材料(BTR-HyECC)单轴受压力学性能的影响,并通过圆柱体单轴受压试验测得各试件受压性能指标,并绘制出应力-应变曲线。结果表明:当钢纤维掺量为0%(体积分数,下同)时,随着玄武岩织物的加入,试件的抗压强度、峰值应变以及抗压韧性显著提高;当钢纤维掺量增加到1%时,试件抗压强度和弹性模量达到最大;当钢纤维掺量为1.5%时,试件变形能力和抗压韧性达到最佳。基于试验数据,建立了适用于BTR-HyECC的单轴受压本构方程,拟合曲线与试验曲线吻合较好。

压弯剪扭复合作用下灌浆套筒装配式RC墩的抗震性能

随着城市交通的快速发展,对其建设要求越来越高,城市桥梁主要为匝道桥、斜交桥等非规则桥梁.为得到压弯剪扭等复合地震作用下装配式墩的损伤机理和滞回特性,进行了灌浆套筒连接(Grouting Sleeve,GS)、灌浆套筒和钢管混凝土剪力键组合连接(Grouting Sleeve and Steel-tube,GSS)装配式墩和钢筋混凝土现浇(Reinforced Concrete,RC)墩等三种桥墩在压弯剪扭复合作用下的拟静力试验.结合现有混凝土结构设计规范计算剪扭相关曲线,并与试验结果进行对比,分析装配式墩复合荷载作用下的剪扭承载能力.结果表明:GS构件与RC构件以压弯扭破坏为主,而插入钢管剪力键的GSS构件则发生塑性铰上移,呈现出剪扭破坏的特征.GS构件和RC构件具有较好的弯曲耗能能力,增加钢管剪力键的GSS构件则可以提升抗弯承载力.装配式墩接头导致其整体性较弱,GS构件和GSS构件抗扭承载力小于RC构件.各构件在复合荷载作用下的剪扭相关关系接近规范中的1/4圆理论曲线,研究结果可以为灌浆套筒连接装配式墩在压弯剪扭复合作用下的抗震性能分析提供参考.

成型钢筋混凝土构件(梁、柱、墙)抗震性能研究进展

成型钢筋具有广阔的应用前景。首先介绍了工程中典型成型钢筋的制备工艺及其在实际工程中的应用现状。然后,概述了成型钢筋混凝土构件(梁、柱、墙)抗震性能的研究进展,重点介绍了本课题组近年来开展的成型钢筋混凝土构件(14根梁、20根柱、6片剪力墙)的抗震性能试验研究。研究表明,与绑扎钢筋相比,采用弯网、穿箍、绕箍成型钢筋的混凝土构件均具有良好的抗震性能。最后,简要介绍了国内首部适用于成型钢筋混凝土构件(梁、柱、墙)的技术标准《成型钢筋混凝土结构设计标准》(DG/TJ 08-2414—2023)。

熔丝制造3D打印CFRP层内损伤破坏机理与模型研究

为将3D打印技术应用到桥梁工程中,以熔丝制造3D打印碳纤维复合材料锚环为研究对象,开展了材料层内损伤失效机理的基础性研究工作.首先,对锚环进行了张拉锚固破坏试验,明晰材料的损伤失效模式.其次,测试分析了材料的弹性参数及强度参数值,供后续仿真分析使用.最后,通过VUMAT子程序构建了材料的损伤失效本构关系,利用ABAQUS仿真分析软件模拟熔丝制造3D打印碳纤维复合材料锚环的渐进损伤失效全过程,分析其层内损伤失效机理.结果表明:熔丝制造3D打印碳纤维复合材料具有显著的层内损伤现象;选用Hashin损伤起始判据与刚度瞬间退化模型作为熔丝制造3D打印碳纤维复合材料损伤力学模型偏于安全,具有一定的可行性;锚环在高度方向产生纵向裂纹是由纤维拉伸失效导致的.

接缝和主梁损伤对装配式多主梁桥荷载横向分布规律的影响研究

为了验证不同损伤对装配式多主梁桥荷载横向分布规律的影响,并探讨基于横向分布规律的桥梁损伤识别方法,考虑接缝损伤程度、主梁局部损伤程度、损伤位置和损伤区域长度的影响,采用刚接板梁法对接缝和主梁损伤情况下装配式多主梁桥的荷载横向分布规律进行了研究。结果表明,接缝损伤后其两侧主梁的横向分布影响线与损伤前的影响线有交点;有损伤的主梁其影响线整体下降,且刚度剩余系数越小、损伤位置距跨中越近、损伤范围越大,下降程度越大;主梁与接缝损伤同时发生时,可通过与敏感梁单独损伤时的影响线进行对比来进行分析。根据损伤前后敏感主梁的横向分布影响线变化规律,可对桥梁的损伤类别进行识别,但无法识别具体损伤位置。

Ion engine grids：Function,main parameters,issues,configurations,geometries,materials and fabrication methods

Ion optics are crucial components of ion thrusters and the study of the different ion extraction solutions used since the beginning of the electric propulsion era is essential to understand the evolution of ion engines. This work describes ion engine grids＇ main functions, parameters and issues related to thermal expansion and sputter erosion, and then introduces a review of ion optics used for significant launched and tested ion thrusters since 1970. Configurations, geometries, materials and fabrication methods are analyzed to understand when typical ion thrusters use two or three grids, what are the thicknesses and aperture sizes of the screen, accelerator and decelerator grids, why molybdenum and carbon-based materials such as pyrolytic graphite and carbon–carbon are the best available options for ion optics and what is the manufacturing method for each material.

Reconfigurable directional coupler in lithium niobate crystal fabricated by three-dimensional femtosecond laser focal field engineering

For crystals, depressed cladding waveguides have advantages such as preservation of the spectroscopic as well as non-linear properties and the capability to guide both horizontal and vertical polarization modes, but fabrication is always quite time consuming. In addition, it is usually difficult to couple modes propagating in different depressed cladding waveguides through evanescent field overlap, so it is often required to dynamically reconfigure photonic waveguide devices using external fields for classical or quantum applications. Here, we experimentally demonstrate the single-scan femtosecond laser transverse writing of depressed cladding waveguides to form a 2 × 2 directional coupler inside lithium niobate crystal, which is integrated with two deeply embedded microelectrodes on both sides of the interaction region to reconfigure the coupling. By focal field engineering of the femtosecond laser, we specially generate a three-dimensional longitudinally oriented ring-shaped focal intensity profile composed of 16 discrete spots to simultaneously write the entire cladding region. The fabricated waveguides exhibit good single guided modes in two orthogonal polarizations at 1550 nm. By applying voltage to the deeply embedded microelectrodes fabricated with the femtosecond laser ablation followed by selective electroless plating, we successfully facilitate the light coupling from the input arm to the cross arm and thus actively tune the splitting ratio. These results open new important perspectives in the efficient fabrication of reconfigurable complex three-dimensional devices in crystals based on depressed cladding waveguides.

小口径光学零件高效加工实验设计与教学实践

面向迅速发展的车载镜头行业对光学零件高效加工技术人才的需求,针对古典加工技术及传统实验教学的不足,以车载镜头中的小口径新月形透镜的高效加工任务为驱动牵引,运用虚实结合、实验教学与产业融合的方法,重构光学零件高效加工实验教学内容,引导学生参与设备操作、工艺设计、作业指导书编制等光学零件加工的全过程.通过闭环式的学习与探究,发现各环节中存在的问题,并提出解决方案,实现对小口径光学零件高效加工工艺的持续改进,激发学生的学习兴趣,不断提升学生的实践及工艺设计能力.

基于裂隙倾角的非均质岩石单轴压缩数值模拟

基于颗粒流计算框架,采用Weibull分布构建含单预制裂纹非均质岩石的力学数值模型,模拟了非均质岩石的单轴压缩试验;分析了预制裂隙倾角θ对岩石数值试样应力-应变响应特征、微裂纹行为及破坏模式的影响。结果表明:非均质岩石的峰值强度σpeak随着岩石均质度m的增大而增大,最终趋于稳定;受预制裂隙倾角θ影响,σpeak有小幅度跌落,最大达7 MPa;非均质岩石数值试样破坏面主要由微观拉伸裂纹组成;非均质岩石宏观破坏模式可分为“逆对角型”“半对偶型”“对耦型”及“顺对角型”4种。

Fabrication of micro-nano patterned materials mimicking the topological structure of extracellular matrix for biomedical applications

With the advent of tissue engineering and biomedicine,the creation of extracellular matrix(ECM)biomaterials for in vitro applications has become a prominent and promising strategy.These ECM materials provide physical,biochemical,and mechanical properties that guide cellular behaviors,such as proliferation,differentiation,migration,and apoptosis.Because micro-and nano-patterned materials have a unique surface topology and low energy replication process that directly affect cellular biological behaviors at the interface,the fabrication of micro-nano pattern biomaterials and the regulation of surface physical and chemical properties are of great significance in the fields of cell regulation,tissue engineering,and regenerative medicine.Herein,we provide a comprehensive review of the progress in the fabrication and application of patterned materials based on the coupling of mechanical action at the micro-and nano-meter scale,including photolithography,micro-contact printing,electron beam lithography,electrospinning,and 3D printing technology.Furthermore,a summary of the fabrication process,underlying principles,as well as the advantages and disadvantages of various technologies are reviewed.We also discuss the influence of material properties on the fabrication of micro-and nano-patterns.

GRF装配式支护结构施工技术研究与应用

城市化进程加速中,基坑工程在城市建设中越发关键。虽然传统的土钉墙等支护技术得到了广泛应用,然而,在环保、节能以及施工效率方面尚有欠缺。将GRF绿色装配式边坡支护技术作为研究主题,通过理论探讨与实例分析,阐述了该技术的设计理念、施工流程及环保优势。研究发现,GRF技术有效提升了施工效率,减少了环境影响,并在实际项目中验证了其可行性与经济性。研究旨在推广这一环保高效的基坑支护方法,促进建筑产业绿色可持续发展。