多层介质频率选择表面的等效电路分析方法

基于数值仿真计算和微波网络理论,提出了一种多层介质中频率选择表面（FSS）等效电路的分析方法。该方法物理过程直观,计算量小,适用于二维任意形状FSS等效电路的精确求解。以方形贴片型FSS为例验证了等效电路模型的准确性,并分析了多层介质对其等效电路参数的影响规律。最后,基于滤波器理论与FSS等效电路模型设计了双层带通型FSS,计算结果表明全波仿真结果与理论计算结果基本一致,为多层FSS的综合设计提供了一种精确设计方法。     

城市LUCC时空格局对地表温度的影响效应研究 ——以广西柳州市为例

研究目的:定量分析中国西南典型重工业城市——柳州市的土地利用、地表温度时空演化特征以及不同土地利用类型对地表温度的联合影响效应。研究方法:利用1991年Landsat 5的TM影像和2013年Landsat 8的OLI/TIRS影像数据,通过遥感技术反演提取研究区归一化植被指数(NDVI)、归一化差异建筑指数(NDBI)、改进的归一化差异水体指数(MNDWI)以及地表温度(LST)等遥感参数,基于遥感指数叠加分类法获取城市土地利用/覆盖(LUCC)信息。研究结果:(1)柳州市22年间LUCC变化剧烈,受人为因素影响强烈的地物类型为建筑用地、耕地和裸地。其中,建筑用地变化幅度最大,面积增加了126.71%,新增建筑用地主要源于城市中原有的耕地类型。(2)两期地表温度数据均显示,城市建筑用地的地表温度最高,水体的地表温度最低,建筑用地升温效果显著,是造成城市热岛效应的主要原因之一。(3)影响因子相关性与多元回归分析揭示,城市中各地物类型面积比与地表温度均具有一定的相关性,但差异性较大。其中,建筑用地、裸地与地表温度呈正相关,林地、水体与地表温度呈负相关。研究结论:城市各种LUCC类型的地表温度差异较大,水体和林地在缓解城市热岛效应方面作用十分显著,两者比较,水体的降温效果要优于林地。     

整村统筹土地整备中原农村土地利益协调——基于深圳的案例分析

深圳土地整备作为政府主导推进的存量土地再开发利用的重要模式之一,需要对土地整备中利益协调情况进行针对性分析,继而探寻有效的利益协调路径。引入嵌套博弈理论,对深圳坪山新区金沙、南布和沙湖3个社区整村统筹土地整备试点工作的利益协调进行探析。研究结果表明整村统筹土地整备中利益博弈多层次嵌套开展,博弈的主要要素体现在土地、规划和资金3个方面。深圳整村统筹土地整备原农村土地利益博弈的根源主要来自对原农村土地现状权益和未来发展权益的合理确定,利益协调的路径需要在现状权益的认定以及未来发展权益的落实方面构建通路,这是解决原农村发展问题的关键和根本。     

黎曼浸没在全空间中的特征值估计

给出了一类黎曼浸没在全空间中第一特征值的下界估计．设π：M→N为黎曼浸没,其中M是个非紧致流形,N是个在无穷远点有一个极点的黎曼流形,而且Ric（M）≤-（n--1）k,这里k〉0,如果｜｜H｜｜≤c≤（n-1）,那么,λ1（M）≥{（n-1）k-c}^2/4,从而得到了著名的Mckean定理。     

基于YOLOv3的H型钢表面缺陷检测系统

为了提升H型钢的表面质量和安全系数,设计了一种基于YOLOv3算法的型钢表面缺陷检测系统.设计的检测系统由硬件系统和软件系统组成:硬件系统包括八角架式图像采集装置、电动控制系统和通信系统;软件系统采用YOLOv3目标检测算法.现场测试结果表明:1)检测系统可实时采集图像,并根据H型钢的规格型号能够自动调节图像采集装置结...     

Customer Satisfaction with Consumption Systems

ABSTRACT

Purpose: This research examines how satisfaction toward a product and its associated services offered together by a single provider jointly affects behavioral intentions toward the provider.

Design/methodology/approach: In this study, empirical tests were conducted using longitudinal data spanning 5 years from a multinational company that offers both products and associated services as part of a consumption system to their customers.

Findings: Results show a joint congruent effect of product and services satisfaction on behavioral intentions is linear and positive. It appears that offering great service cannot compensate for less-than-adequate satisfaction toward the product. The results further highlight decreasing customer sensitivity to improvements in both sources of satisfaction and imply that focusing on too high levels of one type of satisfaction for their customers can actually be counterproductive for firms.

Research Limitations: Our model was tested using the data obtained from a single firm. Future research could test this model with data from multiple firms in various different industries and establish broader generalizability to the findings.

Practical Implications: Findings provide managers with insights on how to allocate resources across product and service spaces and to manage product and services revenues over time. Results also indicate that customer behavioral intention ratings are more weighted on product quality over the service received by them. However, mere improvements in the product cannot provide the highest desired results and therefore quality improvements in the product need to be complemented by improvements in service quality.

Originality/Value: There is a rapid emergence of the phenomenon of manufacturers providing both products and services as an integrated consumption system to their customers. While the provision of both product and service subsystems by the same firm leads to certain synergies, there are obvious costs to the development of new service capabilities and coordination with existing product capabilities. Our research intends to address this issue.     

Nonlinear trend stationarity in global and hemispheric temperatures

This study investigates the issue of whether our Earth’s surface temperature exhibits a stochastic trend. Using state-of-the-art econometrics, we analyse the latest available temperature anomaly data. Our results indicate that both global and hemispheric temperatures may appear to have a stochastic trend when in fact they are stationary around a nonlinear deterministic trend and structural breaks are responsible. Furthermore, the nonlinearity found in the temperature trend is more complex than what has been reported in previous studies.     

城市人居光环境与光污染防治——基于建筑表皮技术的城市光污染防治

通过对造成城市光污染成因的分析,阐明了当前城市人居光环境状况以及"光环境影响评价"的缺失对光污染防治工作的影响,特别是针对建筑玻璃幕墙的光污染问题,提出了基于建筑表面技术的城市光污染防治措施。认为在人居光环境问题日益严重的今天,除了从技术角度探讨光污染的防治问题外,还应从行政的层面完善相应的法律法规,尤其要加大"光环境影响评价"的力度,从根本上消除光污染的产生。     

关于电磁场边界条件的另一种合适推求

本文在两个层次上(首先,在一般小直圆柱状盒子面或小长方形回路上,其次,在任意形状小闭合面或小闭合回路上),摒弃不必要的假设,充分利用各个相应矢量在微元范围内为一恒矢量这一特点,从而,合乎逻辑地推得电磁场边界条件。     

表面探伤在起重机械中的应用

基于起重机械表面缺陷类型,结合表面探伤检测时机的分析,探讨表面缺陷检测方法,旨在提高起重机械钢结构的质量,消除安全隐患。