Analysis of Effect of Zn(O,S) Buffer Layer Properties on CZTS Solar Cell Performance Using AMPS

The Cu2ZnSnS4 （CZTS）-based solar cell is numerically simulated by a one-dimensional solar cell simulation soft- ware analysis of microelectronic and photonic structures （AMPS-1D）. The device structure used in the simulation is Al/ZnO：Al/nZn（O,S）/pCZTS/Mo. The primary motivation of this simulation work is to optimize the composition in the ZnO1-xSx buffer layer, which would yield higher conversion efficiency. By varying S/（S＋O） ratio x, the conduction band offset （CBO） at CZTS/Zn（O,S） interface can range from -0.23 eV to 1.06eV if the full range of the ratio is considered. The optimal CBO of 0.23eV can be achieved when the ZnO1-xSx buffer has an S/（S＋O） ratio of 0.6. The solar cell efficiency first increases with increasing sulfur content and then decreases abruptly for x〉 0.6, which reaches the highest value of 17.55% by our proposed optimal sulfur content x= 0.6. Our results provide guidance in dealing with the ZnO1-xSx buffer layer deposition for high efficiency CZTS solar cells.

A spatial decomposition approach for accelerating buffer analysis of vector data

Parallel vector buffer analysis approaches can be classified into 2 types:algorithm-oriented parallel strategy and the data-oriented parallel strategy.These methods do not take its applicability on the existing geographic information systems(GIS)platforms into consideration.In order to address the problem,a spatial decomposition approach for accelerating buffer analysis of vector data is proposed.The relationship between the number of vertices of each feature and the buffer analysis computing time is analyzed to generate computational intensity transformation functions(CITFs).Then,computational intensity grids(CIGs)of polyline and polygon are constructed based on the relative CITFs.Using the corresponding CIGs,a spatial decomposition method for parallel buffer analysis is developed.Based on the computational intensity of the features and the sub-domains generated in the decomposition,the features are averagely assigned within the sub-domains into parallel buffer analysis tasks for load balance.Compared with typical regular domain decomposition methods,the new approach accomplishes greater balanced decomposition of computational intensity for parallel buffer analysis and achieves near-linear speedups.

A Neighborhood Analysis of Underage Tobacco Sales within the Serving Area of a Canadian Public Health Unit

Despite the fact that the sale of tobacco to minors is illegal in Ontario, youth are still able to purchase tobacco. This study aims to determine the geographic variations of underage tobacco sales at the neighborhood level within the Windsor-Essex County Health Unit. Data were collected on all inspections of tobacco retail stores from 2007 to 2011 in the Windsor-Essex County Health Unit. Data were split into season 1 (September-February) and season 2 (March-August) to assess a possible seasonal effect. Relative risks were calculated for each dissemination area (DA) by modeling the risks in a hierarchical Bayesian fashion, incorporating appropriate random effects terms for both spatially correlated and uncorrelated random errors with adjustments for neighborhood income. The association between violation rate and proximity to a school was assessed through a buffer analysis. Elliptical analysis detected a significant cluster of high risk DAs in season 1 in Windsor (p-value = 0.022) but no significant cluster in season 2. Some DAs exhibited higher relative risks of tobacco sales to minors, however after adjusting the model for neighborhood income no excess risk was observed. The results of the buffer analysis showed that in season 1 there was a significantly higher probability (p-value = 0.045) of tobacco vendors located closer to schools to sell tobacco to minors. This analysis demonstrates the utility of a systematic approach to identifying neighborhoods with higher risks of tobacco sales to minors. The insights provided by this exploratory, ecologic study are valuable for program planning and directing tobacco enforcement efforts to high risk areas.

Spatial Analysis for Determining Accessibility to Bus Stops in Kaduna Metropolis

Bus stop accessibility is a vital component of a successful transportation system. This study aimed at spatially analyzing bus stops to determine their physical accessibility considering the connecting roads surrounding the bus stops. This research used satellite imagery, Global Navigation Satellite System and Kaduna State Traffic and Environment Law Enforcement Authority documents. The spatial analysis covered bus stop accessibility and obtained data of transport routes, bus stop coordinates, bus stop spacing and physical characteristics of bus stops. GIS buffer, network and area analysis was used in measuring bus stop accessibility considering the road network surrounding it. The ratio of ideal access coverage to the actual access coverage of a stop was calculated. Paired sample statistics were used to compare ideal and actual access coverage;the finding revealed a significant difference between the ideal and actual access coverage. A range of 0 - 1.0 was used in the analysis where, a bus stop is less accessible the closer the value is to 0, and more accessible the closer the value is to 1.0. Linear regression statistics was used to determine if the level of accessibility of a bus stop is dependent on the length of roads within the buffer. This revealed that at R = 0.694, a strong degree of correlation exists between the level of accessibility and road length within the buffer. The study concluded that before siting bus stops, surrounding road networks need to be considered in order to make them accessible.

某火工分离作动器的冲击抑制技术研究

针对某火工分离作动器分离作用时冲击过大的问题,基于装置结构及工作原理进行冲击特征点分析,在仿真计算设计参数对冲击影响程度的基础上,提出了优化装药设计和设置异型金属缓冲结构相结合的冲击抑制技术。仿真分析及试验验证表明,提出的冲击抑制技术有效,可将该分离作动器的冲击峰值由3 645.30g降至635.55g。本研究为火工装置类产品的降冲击设计提供了参考。

汽车碰撞磁流变脂缓冲器设计与仿真分析

针对目前汽车保险杠阻尼系数不可调,只在特定碰撞工况下具有较理想缓冲性能的缺陷,设计一款工作模式多样、磁场利用率高以及多通道流动的磁流变脂缓冲装置。基于Herschel-Bulkley力学模型推导出阻尼力与速度和电流之间的关系,利用MATLAB/Simulink软件进行汽车碰撞仿真,分析汽车在中低速碰撞时不同电流下汽车碰撞加速度、速度、位移和冲击力变化情况,同时与传统汽车保险杠碰撞进行对比,验证了磁流变脂缓冲装置在汽车碰撞方面具有速度和加速度变化缓慢、冲击力缓冲效果良好、碰撞位移减小的优越性。

无缓冲异步流水线建模与性能分析

无缓冲异步流水线由多台加工周期不同的机器串联组成,广泛应用于汽车、航空发动机等制造领域。无缓冲与异步两大特征直接影响系统状态空间刻画,进而影响产线性能建模。面向无缓冲异步流水线,分析机器随机故障、节拍差异等因素对产线性能的影响,开展产线建模与性能分析研究。从机器维和工件维等两个维度出发,利用活动网络图描述了流水线中工件在机器上的活动状态,刻画了工件保持时间、机器饥饿时间、机器阻塞时间等随机变量与工件完工时间的函数关系,建立了产线性能分析的解析模型。在此基础上,定量分析了系统性能指标与工件保持时间等随机变量之间的关联关系,采用迭代算法求解了生产率、饥饿率和阻塞率等系统性能指标,并通过仿真实验验证了解析模型的有效性。

基于地理空间视角的南沙新区基础设施空间布局分析

完善的教育、医疗体系是衡量城市文明程度和支撑城市高质量发展的基础。本文基于基础性地理国情监测成果,在分析南沙新区交通路网基础设施空间布局现状的基础上,利用地理信息技术的网络分析与缓冲区分析方法,通过定性与定量相结合的方式,对南沙新区的教育、医疗机构等基础设施的可达性分析,从地理空间的角度评价南沙新区基础设施空间布局的合理性,为新区教育、医疗机构设施空间布局优化及未来新区基础设施规划选址提供技术方法与数据参考。

新型可复用着陆缓冲装置设计与分析

针对目前着陆缓冲装置对着陆地形要求较高且不可复用的缺点,参照自然界中的昆虫着陆腿结构的组成,提出一种可复用的基于仿生结构的四腿式着陆器。支撑腿采取“刚性体控制大腿结构+圆弧结构小腿”的组成方式,并采用摩擦制动器作为缓冲吸能装置的设计方法,通过摩擦力做功,使着陆冲击载荷以热能的形式耗散,实现缓冲吸能。应用D-H参数法推导支撑腿的齐次矩阵变换,对该仿生腿式缓降结构进行支撑腿的正逆运动学分析,建立支撑腿的理论模型并进行动力学仿真。进行了整机多工况落震仿真分析并建立了支撑腿小腿的有限元模型,分析飞行器在支撑腿所受冲击力最大情况下的支撑腿小腿应力应变,结果表明可复用着陆器具有良好的着陆缓冲性能,可为我国后续深空探测任务提供一种可行方案。

生物炭特性及其促进厌氧消化效率的研究进展

厌氧消化是处理污水污泥和有机废弃物的有效方式之一,能够产生丰富的清洁能源。但在实际运行中也存在一些问题,例如消化器不稳定,易出现氨、酸抑制等现象。生物炭作为一种吸附剂被广泛应用在去除废水中有毒金属、有机污染等方面,并且通过加生物炭,可有效缓解酸积累和氨抑制,提高厌氧消化产甲烷能力。分析生物炭的理化性质及其表面特性,探究生物炭提升厌氧消化体系缓冲能力、缓解氨抑制的原理,论述了生物炭在厌氧消化体系中对微生物群落结构的影响。

缓冲区分析和空间叠加分析下的智慧石油管网时序标准化片段巡检技术

传统的智慧石油管网时序标准化片段巡检技术仅对采集的数据进行降噪处理,巡检效果不佳。设计了缓冲区分析和空间叠加分析下的智慧石油管网时序标准化片段巡检技术。利用红外图像采集设备,对石油管网运行过程中的数据进行采集,并对采集的数据进行灰度化、对比度增强和降噪处理。利用空间叠加分析的特性,将预处理的图像数据进行叠加,通过计算提取叠加后的图像数据特征,在缓冲区分析的作用下设定巡检路径规划三维空间,通过计算巡检点到虚拟直线之间的距离构建相应的巡检路径规划模型,通过对规划的巡检路径进行评价,判断当前路径是否符合要求,从而完成对石油管网时序标准化片段的巡检。仿真实验表明,缓冲区分析和空间叠加分析下的智慧石油管网时序标准化片段巡检技术的巡检安全性指标为0.954,与传统的智慧石油管网时序标准化片段巡检技术相比巡检效果更好,可靠性更强。

基于GIS的济南市历下区中小学空间覆盖度与可达性研究

以济南市历下区14个街道为例,运用GIS技术的缓冲区分析以及服务区分析法,基于城市道路网、居民居住区点和中小学点位数据,分析济南市历下区59所小学与27所中学的服务覆盖范围和空间可达性。结果表明:历下区总体中小学配置较为合理,学校空间覆盖度与可达性成正相关,由西部主城区向东中小学校的覆盖度与可达性逐步降低,靠近主城区的大明湖街道、解放路街道等中小学覆盖居民区范围较大、可达性较好,智远街道、舜华路街道等中小学覆盖居民区范围相对较小、可达性较差。

航空电子安全关键系统BUFFER空间分析

BUFFER空间分析是安全关键系统验证的重要组成部分,涉及到系统排队理论。通过对一般Buffer队列和周期任务Buffer进行了分析,并对BUFFER空间实例进行了验证,可缩短Buffer消息等待时间,增大Buffer共享的最大消息数,为航空电子安全关键系统BUFFER空间分析提供了可供参考的依据。

合肥市夏季城市公园降温效应与优化策略研究

随着我国城镇的快速化发展,城市热环境问题日益恶化。作为城市绿色空间的重要构成部分,城市公园在优化城市热环境方面具有明显效果。本文以安徽省合肥市主城区的18个城市公园为例,基于Landsat8OLI/TIRS遥感数据通过单窗算法反演出地温数据,采用缓冲区分析法计算城市公园的降温效应特征,从降温幅度和降温距离2个维度量化合肥市城市公园的冷岛效应,并分析公园中影响降温效应的主要因素,以期为城市热环境优化与绿地规划提供参考。

Investigation on performance of all optical buffer with large dynamical delay time based on cascaded double loop optical buffers

Optical buffers are critical for optical signal processing in future optical packet-switched networks. In this paper, a theoretical study as well as an experimental demonstration on a new optical buffer with large dynamical delay time is carried out based on cascaded double loop optical buffers （I：）LOBs）. It is found that pulse distortion can be restrained by a negative optical control mode when the optical packet is in the loop. Noise analysis indicates that it is feasible to realise a large variable delay range by cascaded DLOBs. These conclusions are validated by the experiment system with 4-stage cascaded DLOBs. Both the theoretical simulations and the experimental results indicate that a large delay range of 1-9999 times the basic delay unit and a fine granularity of 25 ns can be achieved by the cascaded DLOBs. The performance of the cascaded DLOBs is suitable for the all optical networks.

一种规模化混杂生产线缓冲区容量优化分配技术

针对传统技术难以解决规模化混杂生产线缓冲区容量分配问题(Buffer allocation problem, BAP),提出了一种规模化生产线递阶分解建模并行寻优技术(Hierarchical decomposition modeling parallel optimizing technique of large-scale production lines, HDMPOT).该技术结合混杂生产线系统综合方法与分解方法的技术思想,兼顾生产线平衡性与系统规模,将原系统递阶分解为包含虚拟生产线在内的n+1个子生产线系统,通过求解子系统的最优解构造原系统的渐近最优解,并在系统递阶建模阶段,提出了一种设备模糊聚类的辅助方式;同时,基于混杂生产线系统综合方法,提出了一种系统渐次综合的初解改进确定方法;并提出了一种通过构造动态步长来设计领域结构的改进型禁忌搜索算法(Simple tabu search, STS),对子系统进行并行寻优.最后,对技术算法的收敛性进行了证明.提出的生产线递阶分解建模并行寻优技术具有一般性,对受设备随机故障等随机事件影响的生产线,尤其是规模化生产线系统其他优化、控制问题也具有借鉴和参考价值.

基于POI数据的昆明市旅游资源空间分布及影响因素研究

旅游资源是发展旅游的重要基石,为了提升旅游资源利用效率,优化旅游产业布局,以昆明市为研究区域,通过利用POI数据进行缓冲区分析、核密度估计等方式,初步对昆明市旅游资源分布特征进行研究.实验结果表明,昆明市旅游资源分布总体上趋于集聚,在各个地区的数量分布不均衡.昆明旅游资源核密度呈现“中心高、四周低”的分布特征.高等级旅游资源与道路等要素对昆明旅游资源空间分布有重要影响.研究可为同一城市内不同发展水平地区的旅游产业差异化发展、空间管理与产业规划提供理论与实践参考.

海洋电磁测量单点系泊潜标系统平衡姿态分析

针对海洋电磁测量单点系泊潜标系统,以预定海域的实际海洋水文资料为背景,采用集中质量法建立了潜标系统模型,并对潜标系统的平衡姿态及缆索的拉力分布进行了仿真分析。结果表明:潜标测量系统各测量节点间保持了良好的线性相关性,线性相关系数保持在0.995以上;配重缓冲缆结构能够实现良好的防浪缓冲效果。现场海试数据分析表明,浮标静浮力为600 N,缓冲缆长为150 m,按40 m长1 N/m的方式配重的潜标系统,在表层海流速度为0.5 m/s的情况下,可以形成缓冲深度达21 m的U形缓冲带,与仿真分析的结果基本吻合。

郑州市热岛效应及其影响因素研究

利用8期Landsat影像,采用单窗算法反演郑州市主城区地表温度,综合分析2001—2021年郑州市热环境变化情况。基于土地覆盖类型数据,利用单因素方差分析法,研究不同土地覆盖类型对应地表温度的差异性,以及不透水面丰度、归一化植被指数与地表温度的关系;对湿地公园建立地表温度缓冲区,研究湿地公园对热岛效应的缓解作用。结果表明,2001—2021年郑州市热岛面积先增加后减少,呈倒U型变化趋势;城市热岛效应受土地利用类型、植被覆盖等因素影响,不同土地覆盖类型对应的地表温度存在显著性差异,地表温度与不透水面丰度呈正相关关系,与归一化植被指数呈负相关关系,湿地公园对热岛效应有明显的缓解作用。

基于GIS空间分析技术的城市体检关键技术研究

基于GF-2卫星影像数据、路网数据、POI数据,应用缓冲区分析、最短路径分析等GIS空间分析技术对凤阳县在宜居城市维度中的典型指标城市综合医院覆盖率和公交站点覆盖率进行研究。结果表明,凤阳县城市综合医院覆盖率为91.98%,评价结果为良,布局合理,可进一步优化;公交站点覆盖率为80.11%,评价结果为中,虽基本满足居民公交可达需求,但覆盖能力不足。23项宜居城市维度指标评价结果为6项优、9项良、4项中、4项差,总体优良比例为65.22%,表现良好,公共服务设施的平衡性和共享水平有待提高。GIS可视化特征能更直观地识别城市发展中的问题,提高城市宜居性评价精度。