Decade Milestone Advancement of Defect-Engineered g-C_(3)N_(4) for Solar Catalytic Applications

Over the past decade, graphitic carbon nitride(g-C_(3)N_(4)) has emerged as a universal photocatalyst toward various sustainable carbo-neutral technologies. Despite solar applications discrepancy, g-C_(3)N_(4) is still confronted with a general fatal issue of insufficient supply of thermodynamically active photocarriers due to its inferior solar harvesting ability and sluggish charge transfer dynamics. Fortunately, this could be significantly alleviated by the “all-in-one” defect engineering strategy, which enables a simultaneous amelioration of both textural uniqueness and intrinsic electronic band structures. To this end, we have summarized an unprecedently comprehensive discussion on defect controls including the vacancy/non-metallic dopant creation with optimized electronic band structure and electronic density, metallic doping with ultraactive coordinated environment(M–N_(x), M–C_(2)N_(2), M–O bonding), functional group grafting with optimized band structure, and promoted crystallinity with extended conjugation π system with weakened interlayered van der Waals interaction. Among them, the defect states induced by various defect types such as N vacancy, P/S/halogen dopants, and cyano group in boosting solar harvesting and accelerating photocarrier transfer have also been emphasized. More importantly, the shallow defect traps identified by femtosecond transient absorption spectra(fs-TAS) have also been highlighted. It is believed that this review would pave the way for future readers with a unique insight into a more precise defective g-C_(3)N_(4) “customization”, motivating more profound thinking and flourishing research outputs on g-C_(3)N_(4)-based photocatalysis.

基于Unreal Engine4的虚拟建模研究

首先比对传统家居设计方式介绍了当前虚拟现实技术的发展情况,关注当前流行的几款虚拟建模软件,阐述了目前UE4软件国外与国内的研究现状。详细介绍了UE4家居建模的流程,包括前置工作与UE4部分两个模块。使用3ds Max 2018软件搭建卧室环境模型,接着对比两种方法将3ds Max 2018生成的模型导入到UE4软件中,着重介绍使用DataSmith插件导出udatasmith文件再导入到UE4软件中的过程,在UE4中对卧室家居环境详细修改、调整光源、物体材质等,最后对日后UE4大型场景的创建与研究进行了展望。

Selective sulfur conversion with surface engineering of electrocatalysts in a lithium-sulfur battery

The sluggish kinetics of multiphase sulfur conversion with homogeneous and heterogeneous electrochemical processes,causing the“shuttle effect”of soluble polysulfide species(PSs),is the challenges in terms of lithium-sulfur batteries(LSBs).In this paper,a Mn_(3)O_(4-x) catalyst,which has much higher activity for heterogeneous reactions than for homogeneous reactions(namely,preferentialactivity catalysts),is designed by surface engineering with rational oxygen vacancies.Due to the rational design of the electronic structure,the Mn_(3)O_(4-x) catalyst prefers to accelerate the conversion of Li2S4 into Li_(2)S_(2)/Li_(2)S and optimize Li_(2)S deposition,reducing the accumulation of PSs and thus suppressing the“shuttle effect.”Both density functional theory calculations and in situ X-ray diffraction measurements are used to probe the catalytic mechanism and identify the reaction intermediates of MnS and Li_(y)Mn_(z)O_(4-x) for fundamental understanding.The cell with Mn_(3)O_(4-x) delivers an ultralow attenuation rate of 0.028% per cycle over 2000 cycles at 2.5 C.Even with sulfur loadings of 4.93 and 7.10mg cm^(-2) in a lean electrolyte(8.4μL mg s^(-1)),the cell still shows an initial areal capacity of 7.3mAh cm^(-2).This study may provide a new way to develop preferential-activity heterogeneous-reaction catalysts to suppress the“shuttle effect”of the soluble PSs generated during the redox process of LSBs.

基于Unreal Engine 4的家居虚拟展示技术研究

本文是在介绍虚拟现实技术的基础上,分析目前市场对虚拟展示的需求,阐述以应用专业引擎Unreal Engine 4为工具,实现产品模型虚拟展示的设计流程以及各交互功能对应的蓝图Blueprints,最终实现家居虚拟样板间的制作。

Ultrasonic Plasma Engineering Toward Facile Synthesis of Single-Atom M-N4/N-Doped Carbon(M=Fe,Co) as Superior Oxygen Electrocatalyst in Rechargeable Zinc-Air Batteries

As bifunctional oxygen evolution/reduction electrocatalysts,transition-metal-based single-atom-doped nitrogen-carbon(NC)matrices are promising successors of the corresponding noblemetal-based catalysts,offering the advantages of ultrahigh atom utilization effciency and surface active energy.However,the fabrication of such matrices(e.g.,well-dispersed single-atom-doped M-N4/NCs)often requires numerous steps and tedious processes.Herein,ultrasonic plasma engineering allows direct carbonization in a precursor solution containing metal phthalocyanine and aniline.When combining with the dispersion effect of ultrasonic waves,we successfully fabricated uniform single-atom M-N4(M=Fe,Co)carbon catalysts with a production rate as high as 10 mg min-1.The Co-N4/NC presented a bifunctional potential drop ofΔE=0.79 V,outperforming the benchmark Pt/C-Ru/C catalyst(ΔE=0.88 V)at the same catalyst loading.Theoretical calculations revealed that Co-N4 was the major active site with superior O2 adsorption-desorption mechanisms.In a practical Zn-air battery test,the air electrode coated with Co-N4/NC exhibited a specific capacity(762.8 mAh g(-1))and power density(101.62 mW cm^(-2)),exceeding those of Pt/C-Ru/C(700.8 mAh g^(-1) and 89.16 mW cm^(-2),respectively)at the same catalyst loading.Moreover,for Co-N4/NC,the potential difference increased from 1.16 to 1.47 V after 100 charge-discharge cycles.The proposed innovative and scalable strategy was concluded to be well suited for the fabrication of single-atom-doped carbons as promising bifunctional oxygen evolution/reduction electrocatalysts for metal-air batteries.

Unreal Engine4在影视场景中的运用

Unreal Engine4是传统的游戏软件,基于它强大的实时渲染功能,应用于影视特效制作时可以大大改善渲染速度,以适应4K及其他节目的制作。本文以大型纪录片《我们走在大路上》为例,介绍了Unreal Engine4在影视场景中的应用,对资源准备、场景搭建、场景制作等基本的制作流程进行了梳理。

Ignition characteristics and combustion performances of a LO_2/GCH_4 small thrust rocket engine

A 500 N model engine filled with LO2/GCH4 was designed and manufactured.A series of ignition attempts were performed in it by both head spark plug and body spark plug.Results show that the engine can be ignited but the combustion cannot be sustained when head spark plug applied as the plug tip was set in the gaseous low-velocity zone with thin spray.This is mainly because flame from this zone cannot supply enough ignition energy for the whole chamber.However,reliable ignition and stable combustion can be achieved by body spark plug.As the O/F ratio increases from 2.61 to 3.49,chamber pressure increases from 0.474 to 0.925 MPa and combustion efficiency increases from 57.8%to 95.1%.This is determined by the injector configuration,which cannot produce the sufficiently breakup of the liquid oxygen on the low flow rate case.

A New α Ti Alloy (Ti-4Al-2V) for Marine Engineering

NIN has developed a new type of Ti alloy. It is suitable for structure pieces applied in hightemperature and high-pressure water/steam conditions. Its nominal composition is Ti-4Al-2V. In this paper, its microstructure, mechanical properties and corrosion resistance were studied in detail.

基于Unreal Engine 4虚拟引擎模拟《数据结构》最短路径问题

现在高校的课堂教育模式不断进步,这些新方式的不断加入,给课堂增添了许多新意。本项目使用虚拟现实技术,利用了Unreal Engine 4引擎与3Ds Max系统创建了虚拟现实技术在计算机专业课程辅助教学中的应用项目,用于辅助教师的课堂教学,让教师的教学方式更加多样化,给学生以更好的学习体验。本项目应用于高校课堂教学。

基于Unreal Engine 4虚拟引擎模拟高校火灾逃生系统

高校火灾逃生具有很重要的教育意义,在现实中我们很难在真实的火灾现场中进行逃生演练。所以本项目使用虚拟现实技术,利用了Unreal Engine 4引擎与3Ds Max系统创建了火灾场景与场景中的虚拟人物,用于模仿真实地火灾发生场景,让人们有真实的体验感觉。本项目应用于模拟火灾逃生的训练。

湖南省新田县富锶岩溶水矿物饱和指数特征,Sr^(2+)、SO_(4)^(2-)来源及开发潜力

【研究目的】湖南新田县发现大型富锶矿泉水田,然而锶元素来源及锶矿泉开发利用潜力研究相对薄弱,此外探究富锶岩溶水水化学特征及锶元素来源可为岩溶区寻找富锶地下水提供一定的理论支撑。【研究方法】通过开展水文地质调查,富锶地下水水化学指标检测分析,利用PHREEQC软件、水化学计量法、端元法、水文地质参数等揭示富锶岩溶水矿物饱和指数特征,Sr^(2+)、SO_(4)^(2-)来源及富锶地下水开发潜力。【研究结果】方解石在下降泉和机井中均主要处于饱和状态,白云石由下降泉中未饱和状态转为机井中的饱和状态,菱锶矿在机井中出现饱和状态,石膏在下降泉和机井中均为未饱和状态。下降泉中矿物饱和指数随泉水溶解性总固体增加而升高,两者呈较好的正相关关系,但在机井中两者相关性较差。下降泉SO_(4)^(2-)和大气降水SO_(4)^(2-)具有较好的拟合关系,根据Ca^(2+)、Mg^(2+)、Sr^(2+)、HCO_(3)^(-)、SO_(4)^(2-)化学计量关系,机井中SO_(4)^(2-)可能来源于石膏溶解。下降泉中Sr^(2+)主要来源于石灰岩中以类质同像置换钙的锶,机井中Sr^(2+)较大可能来源于含水层中菱锶矿。研究区85.2%水点的地下水符合国家生活饮用水卫生标准,超标水点多为单指标超标。经计算,枯水年富锶地下水天然补给资源量、可开采资源量和地下水资源潜力分别为3.83×10^(7)m^(3)/a、1.05×10^(7)m^(3)/a、7.28×10^(6)m^(3)/a。【结论】新田县富锶地下水中锶主要来源于泥盆系佘田桥组地层含锶矿物(类质同像置换钙的锶和菱锶矿)的溶解,富锶地下水资源量及资源潜力可观,具有较大的开发利用潜力与价值。

基于Unreal Engine4平台的大地形建模方法研究

构建高精度的地形模型是虚拟现实漫游系统中的关键技术,真实大地形模型的构建过程较为复杂,精度难以保证。本文根据工程行业真实地形的基本要素划分为工程区域和非工程区域,应用三维激光扫描技术获取高精度地形数据,在降低资源消耗、保证精度的前提下对点云数据进行了精简处理。阐述了一种地形高度图的生成方法,实现了基于Unreal Engine4开发引擎的真实大地形模型创建,最终构建了体现细节层次的大地形模型。

Simulation Research on the Effect of 2-Stroke Engine Exhaust Resonance on Aspiration

Exhaust resonance effect on the 2-stroke engine aspiration is investigated via one-dimensional simulation on GT-Power.Result shows that exhaust resonance is established when the number of oscillation periods per engine cycle derived from the engine speed and exhaust length is an integer.Exhaust resonance may raise or lower the trapping ratio,and the specific effect depends on the value of the number of oscillation periods per engine cycle.There is a liner regression relationship between the trapping ratio and average after back pressure.The primary way to improve the trapping ratio with the exhaust resonance is to increase the average after back pressure.The optimum exhaust resonance state is the one that suits the port timings so that the peak of exhaust pressure lies within the after charging period,raising the average after back pressure.For the case where the exhaust duration is 184°CA and the scavenge duration is 111°CA,the optimum number of oscillation periods per engine cycle is 3.

《雄安——未来正来》制作心得——Unreal Engine4虚幻引擎与虚拟演播室的结合应用

本篇文章以金帆奖演播室图形技术二等奖作品《雄安—未来正来》的制作方式为例,介绍了Unreal Engine4虚幻引擎的特点和其与虛拟演播室成功结合的先决条件,并以中科大洋eMagic虛拟演播室系统为例,介绍了此系统利用Unreal Engine4虚幻引擎逼真的画面优势制作虛拟场景的制作方法和使用心得。

基于Unreal Engine4引擎的虚拟校园游戏设计

随着近几年游戏产业的迅速发展,校园模拟类型的游戏迎来了蓬勃发展期。基于Unreal Engine4游戏引擎过硬的实力和出众的画面表现力,设计了一款虚拟校园游戏软件。

Bandgap engineering of hierarchical network-like SnIn4S8 microspheres through preparation temperature for excellent photocatalytic performance and high stability

The effect of synthesis temperature and reaction time on the visible-light photocatalytic activity of hierarchical network-like SnIn4S8 microspheres was investigated by the low-temperature co-precipitation strategy. The preparation temperature and reaction time have great influence on the photocatalytic activity of SnIn4S8, and the optimal preparation temperature and reaction time are 70℃ and 3 h, respectively.The SnIn4S8 shows good reusability and high stability with no observable decrease of photocatalytic activity in five consecutive cycles.

23rd International Conference on Coastal Engineering 4-9 October 1992, Venice, ITALY

Organized by Consiglio Nazional delle Ricerche (CNR), Gruppo Nedonale diIdraulice(GNI) with the support of the Ministry of Public Works and under the auspices of theCoastal Engineering Research Council(CERC) of the American Society of CivilEngineering(ASCE), and co-sponsored by the international Association for Hydraulic of Navi-gation Congress(PIANC) and by the Associazione di Ingegneria Offshore e Marina(AIOM).Aim

基于Unreal Engine4的虚拟家装系统设计

采用Unreal Engine4为虚拟家装系统开发平台,以BluePrints和C++为编程语言,实现了虚拟现实在虚拟家装系统中的关键性交互技术应用。本文完善优化了传统交互功能,如视角漫游、切换模型材质、开关灯/电视、搭建Wamp服务器添加用户注册登录等。在传感交互上,基于MPU6050陀螺仪实现模型的姿态控制。测试结果表明,系统不仅完成上述功能,在传统交互功能上极大的节约了家装公司与用户沟通的时间成本,而传感交互的实现则以低成本的投入增强了系统的沉浸感与体验感。

Correlation of Performance, Exhaust Gas Temperature and Speed of a Spark Ignition Engine Using Kiva4

The objective of this study was to investigate performance characteristics of a spark ignition engine, particularly, the correlation between performance, exhaust gas temperature and speed, using Kiva4. Test data to validate kiva4 simulation results were conducted on a 3-cylinder, four-stroke Volkswagen (VW) Polo 6 TSI 1.2 gasoline engine. Three different tests were, therefore, carried out. In one set, variations in exhaust gas temperature were studied by varying the engine load, while keeping the engine speed constant. In another test, exhaust gas temperature variations were studied by keeping the engine at idling whilst varying the speeds. A third test involved studying variations in exhaust gas temperature under a constant load with variable engine speeds. To study variations in exhaust gas temperatures under test conditions, a basic grid/mesh generator, K3PREP, was employed to write an itape17 file comprising of a 45° asymmetrical mesh. This was based on the symmetry of the combustion chamber of the engine used in carrying out experimental tests. Simulations were therefore performed based on the input parameters established in the conducted tests. Simulations with the kiva4 code showed a significant predictability of the performance characteristics of the engine. This was evident in the appreciable agreement obtained in the simulation results when compared with the test data, under the considered test conditions. A percentage error, between experimental results and results from simulations with the kiva4 code of only between 2% to 3% was observed.