Pyrolysis preparation of WO_3 thin films using ammonium metatungstate DMF/water solution for efficient compact layers in planar perovskite solar cells

The tungsten trioxide（WO3） thin films were firstly prepared by spin-coating-pyrolysis methods using the ammonium metatungstate（（NH4）6H2W12O40）DMF/water solution, and successfully applied as the efficient compact layers for the planar perovskite solar cells. The influence of the WO3 film thickness and the rinsing treatment of CH_3NH_3 PbI_3 thin film with isopropanol on the photovoltaic performance of the corresponding perovskite solar cells was systematically investigated. The results revealed that the perovskite solar cell with a 62 nm thick WO3 compact layer achieved a photoelectric conversion efficiency of 5.72%, with a short circuit photocurrent density of 17.39 mA/cm^2, an open circuit voltage of 0.58 V and a fill factor of 0.57. The photoelectric conversion efficiency was improved from 5.72% to 7.04% by the isopropanol rinsing treatment.

Study on Improvement of Dumping Site Stability in Weak Geological Condition by Using Compacted Layer

Berau Basin, a sub-basin of Tarakan Basin, had been developed during Eocene to Miocene period. Rocks in Berau Basin consist of sedimentary, volcanic and igneous rocks aged from Pre-tertiary until Quaternary epoch. The youngest identified rock formation was alluvial deposit consists of mud, silt, sand, gravel and swamp with brown to dark color. This youngest rock formation is relatively weak geological condition and can cause problems in the coal mining operation. PT Berau Coal as one of the coal mining companies in Berau Basin area had experienced some problems related to the occurrence of alluvial deposit. A large failure has occurred at one of its out pit dumping?area which lies over the swamp material. The failure caused a higher operating cost since it made that the distance for waste rock dumping became to be farther than the designated area. Therefore, in order to prevent similar failure occurring at dumping area which lies above swamp material, an improvement of dumping site stability on weak geological condition has to be needed. The proposed method for improving the stability of out pit dumping area in weak geological condition is to construct the compacted layer of waste rock before the out pit dumping area construction. Based on experimental results, a minimum of 40 kPa pressure is needed to give a proper compaction to the waste rock. The result of numerical analysis by Finite Element Method (FEM) shows that construction of compacted layer on the base of out pit dumping area can improve its stability.

EFFECT OF OXIDE LAYER THICKNESS OVER Al AND Al ALLOY POWDERS ON QUALITY OF THEIR EXPLOSIVE COMPACTS

Observations of microstructure of explosive compacts made of Al or Al-Li alloy powders by atomization with water,nitrogen or ultrasoic Ar gas were carried out under optical and scanning electron microscopes.The rsults indicate that super quality explosive compact can only be obtained by powders of which the thickness of the oxide layer is less than 30 nm.

Modified Rammsonde tests in layered compacted snow

Investigation of the physical and mechanical properties of snow has long been a topic of interest to researchers as the construction of compacted-snow runways in Antarctica developed. In an attempt to assess the strength of layered compacted seasonal snow, penetration tests using modified Rammsonde were conducted in Harbin, China in early 2018. Compared with previous models, the modified Rammsonde is lighter overall, with improved resolution;thus, it is more suitable for seasonal snow;the mechanical structure was adjusted, and the reading of depth data is more convenient. A total of 74 penetration tests were carried out and the results were analyzed both qualitatively and quantitatively. The results of these analyses demonstrated the applicability of the device, and revealed that several factors affect the cone penetrometer's estimate of the strength of the layered compacted seasonal snow. Such factors include the confining pressure, penetration energy, and the snow material properties, particularly the compaction of the snow undergoing penetration. A linear relationship between the penetration pressure and snow density was also established. The effect of age hardening on the penetration pressure was studied and the microstructure of the snow particles was observed through a microscope. These analyses showed that the cone penetrometer and data processing methodology applied in this study enable a rapid estimate of strength in seasonal snow, and may be applied in Antarctica after further modification. This would provide a scientific basis for the design of China's Antarctic ice sheet airport.

Auto Identification of Rolling Layers in Roller-Compacted Concrete Dam

A scheme for identifying rolling layers in roller-compacted concrete (RCC) dam automatically was presented. First, a conceptual model was developed. Second, by using a computational geometry method, the auto identification of rolling layers and auto matching between rolling compaction machines and rolling layers were realized based on spatial control points. An application to the construction of Guandi RCC dam showed that the auto identification of rolling layers played an important role in ensuring the engineering quality.

High Order Compact Difference Scheme and Multigrid Method for 2D Elliptic Problems with Variable Coefficients and Interior/Boundary Layers on Nonuniform Grids

In this paper, a high order compact difference scheme and a multigrid method are proposed for solving two-dimensional (2D) elliptic problems with variable coefficients and interior/boundary layers on nonuniform grids. Firstly, the original equation is transformed from the physical domain (with a nonuniform mesh) to the computational domain (with a uniform mesh) by using a coordinate transformation. Then, a fourth order compact difference scheme is proposed to solve the transformed elliptic equation on uniform girds. After that, a multigrid method is employed to solve the linear algebraic system arising from the difference equation. At last, the numerical experiments on some elliptic problems with interior/boundary layers are conducted to show high accuracy and high efficiency of the present method.

河谷区多层软土地基强夯处治分析

文章依托高速公路多层软土地基强夯处治项目,在施工现场选取具有代表性的监测断面开展现场监测,检验河谷区多层软土地基强夯处治效果。由监测数据得出,在强夯处治和路基填筑施工阶段,地基分层沉降、土压力、孔隙水压力和侧向位移增幅均较大,工后逐渐趋于稳定,可说明强夯处治后软基承载力得到有效提升,路基整体结构稳定,加固效果良好。

扬子地块北缘毕机沟岩体下部带堆晶岩结构定量化分析:对层状岩体冷却早期粒间熔体排出机制的约束

层状岩体冷却中—晚期晶粥中粒间熔体的排出被认为与铁钛氧化物的大量结晶关系密切,但在岩体冷却早期铁钛氧化物尚未大量结晶时,粒间熔体能否被有效排出、以及如何排出还需要深入探究。扬子地块北缘毕机沟岩体是我国目前发现的规模最大、分异程度较高且赋存有钒钛磁铁矿矿床的层状岩体。岩体下部带、中部带和上部带分别由斜长橄榄岩、辉长岩和闪长岩组成。本研究以下部斜长橄榄岩相带为对象,通过对斜长石和单斜辉石进行晶体粒度分布(CSDs)和空间展布形式(SDPs)分析,探讨层状岩体冷却早期粒间熔体的排出方式及其控制因素。模拟计算结果表明,样品中封闭粒间熔体比例(FTL)为9%~13%,暗示岩体冷却早期粒间熔体被有效排出。单斜辉石和斜长石的CSD曲线斜率主要为3.36~2.45和2.99~1.87,截距分别为0.45~3.35和1.06~2.83,均具有斜率一致而截距变化较大的特征,与机械压实的CSD曲线一致。单斜辉石和斜长石在SDP图解上均显示负相关关系,也与机械压实趋势一致。因此,毕机沟岩体冷却早期粒间熔体的排出机制为机械压实。在此基础上,我们将毕机沟与全球其他典型层状岩体从岩体规模、粒间熔体和堆晶矿物密度差、晶体堆积速率与压实速率以及晶粥层厚度等方面进行系统对比后发现,在层状岩体冷却早期没有岩浆补给和对流的情况下,当岩体规模相近时,压实受控于堆晶矿物与粒间熔体密度差,密度差越大压实越容易发生;而当岩体规模不同时,规模越大压实越容易发生。

成型方式对应力吸收层沥青混合料性能的影响

开展了旋转压实与马歇尔击实成型对应力吸收层沥青混合料体积和力学性能的影响分析。试验结果表明,应力吸收层配合比设计中可用马歇尔击实50次代替旋转压实50次成型试件,旋转压实试件与马歇尔试件的劈裂抗拉强度、贯入应力均具有良好相关性,换算系数分别为1.347和0.910。提出了基于马歇尔击实方法的应力吸收层设计要求,可更好地进行配合比设计和工地现场质量控制。

基于ZnO纳米棒阵列的钙钛矿太阳电池研究

在钙钛矿太阳电池中利用水热法制备ZnO纳米棒阵列时,TiO_(2)薄膜一般是制备ZnO种子层以及后续生长ZnO纳米棒阵列的基础。因此TiO_(2)薄膜的致密和平滑程度对ZnO纳米棒阵列的生长及相应太阳电池的光伏性能有重要影响。本文通过使用水解-热解法以NbCl5为铌源在FTO导电基底上制备了Nb掺杂的TiO_(2)致密层,有效提升了TiO_(2)薄膜的致密程度,并在此基础上通过水热法成功沉积生长了具有不同长度、直径和面密度的ZnO纳米棒阵列。通过两步连续沉积法在所得ZnO纳米棒阵列上制备了摩尔比为CH3NH3I/CH3NH3Br=85/15的CH3NH3PbI3-xBrx钙钛矿薄膜。使用spiro–OMeTAD作为空穴传输层,组装了基于Nb掺杂TiO_(2)致密层的ZnO纳米棒阵列钙钛矿太阳电池,在相对湿度55%的空气中获得了13.97%的光电转换效率。

落石冲击下压实度对红层泥岩垫层缓冲机制影响研究

西南地区山地众多,落石频发,红层地质分布广泛,工程上红层隧道区可用红层泥岩作为棚洞垫层材料以抵抗落石冲击。但红层泥岩为细粒黏性缓冲材料,与无黏性粗粒材料不同,压实度对其缓冲机制影响仍不明晰,为此开展落石冲击红层泥岩垫层材料模型试验及数值模拟研究。通过搭建室内落石冲击试验平台,进行红层泥岩材料不同压实度下的模型冲击试验,监测落石及垫层内加速度大小,研究压实度对垫层缓冲效果的影响规律,并借助离散元(PFC)与有限差分(FLAC)耦合方法对模型试验进行了对比验证,揭示了压实度对红层泥岩垫层缓冲机制的影响规律。研究结果表明:1)不同压实度中(K=0.9、0.8、0.7),压实度越低,落石冲击力越小,K=0.7的冲击力较K=0.9减少54.08%;2)垫层内峰值加速度随水平距离增加呈指数衰减,且压实度越小,垫层加速度衰减越显著;3)重复冲击使垫层缓冲效果存在劣化现象,导致落石冲击力及垫层内加速度增加,工程中需加以注意;4)压实度低时,力链越不稳定,力链因易破坏重组而无法提供长期、稳定阻力,致使落石冲击力降低;同时垫层松散使冲击波传播时间增加,垫层吸收更多能量;因此,压实度低时垫层具有更好的缓冲效果。研究结果可为西南地区红层泥岩垫层材料的应用提供借鉴。

有压与无压烧结雪无侧限抗压强度对比试验研究

雪层烧结是全球高纬度寒区雪跑道建造的重要环节,是指雪颗粒间胶结强度随时间不断增长的过程。为确定压实雪层烧结时间设计值,并深入对比有压烧结和无压烧结雪层烧结强度变化规律,自主研发加压设备进行无侧限抗压强度试验。研究表明,无侧限压缩应力-应变曲线呈现有峰值强度和无峰值强度两种形式,有峰值的情况更易发生在高压和长烧结时间下。有压烧结时雪颗粒不断受到挤压,促进雪融化成水,有利于冰的形成,故雪的密度随烧结时间延长先快后慢不断增长,而无压烧结时密度基本不发生变化,进而造成有压烧结雪样的强度和弹性模量均大于无压烧结雪样。无压烧结15 d后雪的强度增长显著放缓,故雪跑道建设过程中,在烧结温度为-10℃左右,建议取15 d作为压实雪层烧结时间设计值。研究成果可用来指导雪跑道建造中雪层强度指标和变形指标的确定。

Spray Pyrolyzed TiO2 Embedded Multi-Layer Front Contact Design for High-Efficiency Perovskite Solar Cells

The photovoltaic performance of perovskite solar cells(PSCs)can be improved by utilizing efficient front contact.However,it has always been a significant challenge for fabricating high-quality,scalable,controllable,and cost-effective front contact.This study proposes a realistic multi-layer front contact design to realize efficient single-junction PSCs and perovskite/perovskite tandem solar cells(TSCs).As a critical part of the front contact,we prepared a highly compact titanium oxide(TiO2)film by industrially viable Spray Pyrolysis Deposition(SPD),which acts as a potential electron transport layer(ETL)for the fabrication of PSCs.Optimization and reproducibility of the TiO2 ETL were discreetly investigated while fabricating a set of planar PSCs.As the front contact has a significant influence on the optoelectronic properties of PSCs,hence,we investigated the optics and electrical effects of PSCs by three-dimensional(3D)finite-difference time-domain(FDTD)and finite element method(FEM)rigorous simulations.The investigation allows us to compare experimental results with the outcome from simulations.Furthermore,an optimized single-junction PSC is designed to enhance the energy conversion efficiency(ECE)by>30% compared to the planar reference PSC.Finally,the study has been progressed to the realization of all-perovskite TSC that can reach the ECE,exceeding 30%.Detailed guidance for the completion of high-performance PSCs is provided.

模拟温压实的常温再生混合料二次成型温度研究

为使室内常温再生沥青混合料设计真实反映现场实际工况,结合4条高速常温再生实体工程,实测了上覆热拌沥青混合料(HMA)施工过程中常温再生层中不同深度处的温度,分析了不同常温再生层厚度、不同上覆HMA厚度以及不同气候施工对常温再生层温度场的影响,建立了常温再生层不同深度处的温度预估方程;同时测试了不同施工大气温度下常温再生层芯样及室内试件的体积参数和力学性能。结果表明:上覆HMA摊铺过程中,再生层内部温度变化受施工环境影响较大;施工大气温度以及室内二次成型温度对常温再生混合料空隙率、抗弯拉强度、抗剪强度及断裂功影响显著,施工大气温度为30℃左右时,相比于0℃左右,空隙率降低约25%,抗弯拉强度、抗剪强度及断裂功分别至少提升45%、66%、77%;室内二次击实温度为80℃时,相比于40℃,空隙率降低约20%,抗弯拉强度、抗剪强度及断裂功分别至少提升42%、35%、80%;室内常温再生混合料设计时,应考虑二次成型温度的影响,以模拟现场再生层因内部温度变化而对混合料性能产生的影响。

应力吸收层沥青混合料压实特性研究

为了解应力吸收层沥青混合料的压实特性,保证施工和易性,采用旋转压实仪成型试件,利用压实度与旋转次数的关系研究油石比、压实温度和矿料级配对压实特性的影响。结果表明:压实能量指数、压实速率、95%和99%压实度对应的压实次数均可作压实参数,压实速率对应力吸收层沥青混合料适用性不强,95%和99%压实度对应的合理压实次数为10次和35次,其可用于确定最佳油石比,提出了应力吸收层沥青混合料关键筛孔1.18 mm和2.36 mm合理通过率范围分别为45%~50%和65%~75%。

基于CompactRIO的高速转塔式测试分选控制系统设计

对高速转塔式测试分选控制系统进行设计;介绍了单颗芯片测试的整个工序流程,在此基础上采用CompactRIO为核心控制器,运用模块化设计方法建立了分选机系统控制框架,各模块与控制器之间的连接通过总线或者I/O口连接在一起;在软件架构上采用三层软件架构的设计方法对分选机控制系统进行设计,讨论了三层架构即表示层,逻辑层,操作层在转塔式测试分选机软件架构上的作用,且三层之间的联系是表示层联系逻辑层,逻辑层联系操作层,操作层与外界各个硬件的沟通,此外对芯片检测数据流存储进行了设计;这种控制系统设计能较大地提高转塔式测试分选机的工作效率和运行速度。

烟草垄体分层施肥土壤镇压试验与肥料颗粒偏移分析

【目的】研究烟草起垄分层施肥镇压复合作业时,镇压压强P与土壤下陷量B的关系、土壤下陷量B与据表层150 mm处的土壤坚实度M的关系及土壤内部肥料颗粒的偏移情况,为镇压装置与分层施肥装置关键结构的设计提供理论基础。【方法】通过改变施加载荷的大小进行镇压试验,测量垄体表层土壤下陷量B和距离表层150 mm处的土壤坚实度M,获得P-B曲线和B-M曲线,根据烟草移栽农艺要求确定土壤下陷量B和压强P的范围。通过EDEM仿真,得到土壤镇压作业时内部颗粒的偏移情况。【结果】得到了在符合作物生长需求的条件下,镇压产生的土壤下陷量B的范围为5~33 mm,相应施加在土壤表面的压强P为5~23 kPa;在土壤下陷量B为25 mm时,分层施肥肥料颗粒向下偏移量分别为20.2、15.1、7.7、4.8 mm,与镇压试验结果误差为10.0%~14.6%。最后通过田间试验进行验证。【结论】根据土壤压缩及内部颗粒偏移规律设计分层施肥镇压装置,垄内分层施肥深度稳定,整形效果良好,可为镇压装置及垄内分层施肥装置的设计提供参考。

深厚软基超长防波堤爆炸挤淤快速施工技术

含有深水较厚淤泥层的软基加固处理难度大,海上施工工况复杂,一直是软基处理工程的难点。在渔港斜坡式防波堤建设工程中,针对淤泥层厚、抛填方量大、防波堤长度大的特点,采用爆炸置换方法进行挤淤施工。防波堤总长2 180 m,抛石量约434万m3,为加快施工速度,构筑了双人工岛施工方法,人工岛尺寸为36 m×36 m,增加了同时工作面。在合拢段采用子堤拓宽法施工,子堤宽度8 m,由内侧向外侧推进完成合拢。经沉降点观测和钻孔取样,防波堤建设取得了较好的质量效果,可为相似工程提供借鉴经验。

高速公路路基分层填筑技术分析

以某高速公路项目为研究背景,对路基分层填筑后分层压实技术和分层强夯技术的具体应用进行了研究,并对两种施工工艺的质量控制进行了分析。最终通过路基压实度、平整度以及横向坡度的检测结果可知,该高速公路项目试验路段路基采用分层强夯技术能获取更优的施工质量。

考虑同层后道工序的柔性设备网络综合调度算法

针对柔性设备网络综合调度算法,难以合理选择加工设备加工相关工序进而影响产品完工时间的问题,该文提出考虑同层后道工序的柔性设备网络综合调度算法(SP-FENIS)。首先,采用逆序层优先策略,将各工序分配至逆序层待调度工序集;然后,提出均值逆序紧后路径策略,确定了各逆序层待调度工序集中工序的调度顺序;最后,提出最早完工时间策略和设备空闲插入策略,当工序在柔性设备上最早完工时间相同时,考虑了在柔性设备上的加工时间和同层后道工序的加工设备,确定了目标工序的加工设备以及加工时间。实例表明,和已有算法相比,该算法能够缩短产品完工时间。