Pattern Dynamics of Thermal-environment Effect During Urbanization:A Case Study in Shenzhen City,China

The thermal-environment effect exists in the field of rapid urbanization.It has adverse effects on the urban atmosphere,regional climate,energy consumption,and public health.Shenzhen,a representative of rapidly urbanizing cities in China,was selected as a case for pattern dynamics analysis of the thermal environment.The surface temperature was acquired from the thermal infrared data of Landsat TM and ETM+ images in 1986,1995,and 2005 by Jiménez-Mu?oz and Sobrino's generalized single-channel method,which was used in assessing the distribution and spatial patterns of the thermal environment.The relative thermal environment curve(RTC) was combined with Moran's I analysis to assess the pattern dynamics of the thermal environment in different urbanization periods.Moran's I index and the RTC represent a process of aggregation-fragmentation-aggregation,which shows the aggregation pattern of a decrease during the rapid urbanization period and then an increase during the steady urbanization period.High-temperature areas gradually expanded to a uniform and scattered distribution in the rapid urbanization period;while the high thermal-environment effect was gradually transformed into a steady spatial pattern in the stable urbanization period.To characterize the increasing development in this multiple-center city,we chose profiles along an urban-development axis.The results suggest that heat islands have expanded from internal urban to external urban areas.Four profiles were obtained showing differences in shape due to spatial differences in the process of development.

Crack patterns corresponding to the residual strength plateau of ceramics subjected to thermal shock

The formation strength plateau of ceramics is addressed. A set of of 99A1203 are conducted, mechanism of the residual subjected to thermal shock thermal shock experiments where the thin specimens of 1 mm× 10 mm×50 mm exhibit parallel through edge cracks, and thus permit quantitative measurements of the crack patterns. The cracks evolve with the severity of ther- mal shock. It is found that there is a correlation between the length and density of the thermal shock cracks. The increase of crack length weakens the residual strength, whereas the increase of crack density improves it. In a considerably wide temperature range, the two contrary effects just counteract each other; consequently a plateau appears in the variation curve of the residual strength. A comparison between the numerical and experimental results of the residual strength is made, and they are found in good agreement. This work is helpful to a deep understanding of the thermal shock failure of ceramics.

Numerical Simulation of a Courtyard under Different Ground Thermal Conditions and Flow Patterns

The impact of thermal conditions of the ground on ventilation in the interior courtyard and rooms of enclosed building is very important to improve the air quality in courtyard. The computational fluid dynamics( CFD) model was used to investigate the flow field of a certain courtyard and analyze the static differential pressure between the two sides of the vent and ventilation conditions of the courtyard. The results indicate that thermal effects not only changed the air flow pattern of the interior courtyard but also obviously increased the flow velocity of the upper space of the courtyard. For the most of courtyard rooms,the absolute value of static differential pressure increases as the thermal intensity of the ground increases. In all wind directions,the air exchange rate of the courtyard increases with the higher thermal intensity of the ground which makes a greater influence on the increasing of the ventilation rate of the roof opening than that on the gate opening.

Flow patterns and critical criteria of thermally stratified shear flow in braided rivers

Flow characteristics of thermally stratified shear flow in braided rivers are particularly complicated and poorly understood. In this study, a series of typical flow patterns was examined and their critical criteria were determined. Four flow patterns were identified: mixed, locally unstable, continuously stratified, and two-layer flow. Temperature distributions of the four types of flow patterns were analyzed and compared.The critical Froude numbers for unstable flow, FDcr1, and stable flow, FDcr2, were determined to be 6 and 1, respectively, and comparison of FDcr1 and FDcr2 to the peak Froude numbers, FD1 at the outer bank and FD2 at the inner bank along the anabranch, allowed the flow patterns to be assessed. Then, a discriminant based on initial Jeffreys-Keulegan stability parameters was established to distinguish the flow stages from twolayer flow to completely mixed flow. It is indicated that the three critical Jeffreys-Keulegan parameters increased with the diversion angle of braided rivers. Results also show that, compared to the stratified flow in straight and curved channels, it was more difficult for braided stratified flow to maintain as two-layer flow, and it more easily became mixed flow. Consequently, empirical expressions for stability criteria of the thermally stratified shear flow in braided rivers are presented.

基于用户画像的暖通空调智能调控

目前,建筑物中的暖通中央空调系统基本上是根据行业准则设置的,然而,多项研究表明,由于用户的偏好、姿态和需求各异,这种传统做法不太可能满足大多数用户的热量需求。为了更精准地满足用户热量需求,使得基于用户行为模式来针对性提高热舒适性成为可能。文中采用深度强化学习的方法实现智能化暖通空调智能送风策略,该策略能够根据环境和用户行为模式动态地确定最佳暖通空调设置(温度设置和送风设置),从而极大提高用户的热舒适度,同时,实验结果还表明该智能调控策略相比传统固定值控制策略具有一定的节能效果。

基于膦氧化物钝化的热蒸发像素化钙钛矿发光二极管

热蒸发法是实现钙钛矿发光二极管商业化显示应用的可靠技术。然而,热蒸发沉积的钙钛矿薄膜的PLQY经常较低,并且钝化手段不如溶液法丰富。本文报道了一种通过原位共蒸技术将钝化剂引入钙钛矿层的方法,这种方法能够钝化真空沉积钙钛矿中的缺陷,增强辐射复合,并提高钙钛矿的PLQY。氧膦基团与不饱和位点形成配位络合,钝化了钙钛矿的晶界缺陷,并抑制了带尾态缺陷。基于最佳比例的钙钛矿薄膜所制备的LED器件表现出最大6.3%的EQE,最大亮度为35642 cd/m^(2)。更进一步地,基于全真空的器件制备工艺,获得了最大EQE为5.0%的312 ppi高分辨率PeLEDs。总之,本文为热蒸发PeLEDs的缺陷钝化提供了有用的指导,证明热蒸发PeLEDs在效率和亮度提升方面具有巨大潜力,并具备商业化前景。

Numerical Investigation of Laser Surface Hardening of AISI 4340 Using 3D FEM Model for Thermal Analysis of Different Laser Scanning Patterns

Laser surface hardening is becoming one of the most successful heat treatment processes for improving wear and fatigue properties of steel parts. In this process, the heating system parameters and the material properties have important effects on the achieved hardened surface characteristics. The control of these variables using predictive modeling strategies leads to the desired surface properties without following the fastidious trial and error method. However, when the dimensions of the surface to be treated are larger than the cross section of the laser beam, various laser scanning patterns can be used. Due to their effects on the hardened surface properties, the attributes of the selected scanning patterns become significant variables in the process. This paper presents numerical and experimental investigations of four scanning patterns for laser surface hardening of AISI 4340 steel. The investigations are based on exhaustive modelling and simulation efforts carried out using a 3D finite element thermal analysis and structured experimental study according to Taguchi method. The temperature distribution and the hardness profile attributes are used to evaluate the effects of heating parameters and patterns design parameters on the hardened surface characteristics. This is very useful for integrating the scanning patterns’ features in an efficient predictive modeling approach. A structured experimental design combined to improved statistical analysis tools is used to assess the 3D model performance. The experiments are performed on a 3 kW Nd:Yag laser system. The modeling results exhibit a great agreement between the predicted and measured values for the hardened surface characteristics. The model evaluation reveals also its ability to provide not only accurate and robust predictions of the temperature distribution and the hardness profile as well an in-depth analysis of the effects of the process parameters.

嫦娥五号月壤纳米级单质金属铁的形成及生长规律的原位电镜研究

纳米级单质金属铁(纳米铁)是无大气保护的地外星体表层长期受太空风化改造的特征产物,是记录月壤形成与演化信息的关键载体,同时也是影响月表反射光谱遥感探测的主要因素。纳米铁的形成机制除了汽化沉积作用之外,近年来在嫦娥五号月壤中还发现了分解反应和歧化反应成因的纳米铁,但其生长规律和形成条件约束目前尚不清楚。因此,本文采用先进的电镜原位加热技术,选取嫦娥五号月壤中的橄榄石、辉石和陨硫铁等含铁矿物作为研究对象,系统性地模拟月壤中含铁成分的物质在亚固相线条件下(湿度不高于800℃)的热改造过程,记录纳米铁在各矿物中的形成方式及生长规律。通过统计纳米铁的粒径尺寸,探讨不同矿物相中纳米铁的粒径分布,为遥感探测光谱数据的解译提供有价值的参考。

采用锯齿型颗粒释放模式的下落式颗粒吸热器的热性能分析

针对塔式太阳能热发电系统中下落式颗粒吸热器辐射损失大、热效率低的问题,研究了一种改善吸热器中颗粒帘幕光热转换特性的锯齿型颗粒释放模式以提高吸热器热性能。首先,针对塔式系统中的光热耦合过程建立了一个耦合蒙特卡洛光线追迹法和有限体积法的数值集成模型;然后,基于此模型分析了采用不同振幅和波长的锯齿型颗粒释放模式对下落式颗粒吸热器热性能的影响。结果表明:当波长为0.2 m且振幅大于0.3 m时,锯齿型颗粒释放模式可以提高吸热器热性能。最优锯齿型模式的波长为0.2 m、振幅为0.4 m,其吸热器效率相较于传统的直线型模式提高了0.91%。

不同灸法治疗原发性痛经的随机对照试验

目的观察采用智能中医灸疗床进行灸法治疗寒凝血瘀型原发性痛经的临床疗效。方法将60例寒凝血瘀型原发性痛经患者随机分为灸疗床组和局部灸组,每组30例。观察两组治疗前后血清环氧化酶-2(cyclooxygenase-2,COX-2)水平、疼痛视觉模拟量表(visual analog scale,VAS)评分、中医证候积分、焦虑自测量表(self anxious scale,SAS)评分及抑郁自测量表(self depression scale,SDS)评分的变化。比较两组临床疗效。结果灸疗床组总有效率为96.7%,局部灸组总有效率为86.7%,组间差异具有统计学意义(P<0.05)。治疗后及3次随访时,两组VAS评分均较治疗前降低(P<0.05);第2次和第3次随访时,灸疗床组VAS评分均低于局部灸组(P<0.05);第3次随访时,局部灸组VAS评分高于同组治疗后。治疗后及3次随访时,两组中医证候积分均低于同组治疗前(P<0.05)。治疗后,两组血清COX-2水平均低于同组治疗前(P<0.05)。治疗后及3次随访时,两组SAS和SDS评分均低于同组治疗前(P<0.05);治疗后及第2次随访时,灸疗床组SAS评分低于局部灸组(P<0.05);第2次和第3次随访时,灸疗床组SDS评分低于局部灸组(P<0.05)。结论采用智能中医灸疗床进行灸法治疗寒凝血瘀型原发性痛经的临床疗效优于局部灸,可缓解疼痛,改善临床症状。

基于Landsat数据的重庆市热环境时空格局变化研究

针对当前热环境加剧对城市生态环境和人类健康带来的严重威胁,采用辐射传输方程法和Landsat数据对2001年和2019年重庆市主城九区地表温度(Land Surface Temperature,LST)进行反演,对研究区城市热环境时空变化进行研究。基于此选取景观指数和驱动因子对热力景观格局变化和热环境驱动机制进行研究。结果表明:①2001—2019年,重庆市主城九区城市热环境明显增强,高温区域明显增多且整体向北扩张,到2019年LST总体呈现“内高外低”的分布格局。②中温区最大斑块指数增长了近12倍,代替次低温区成为研究区优势斑块类型。斑块数量和密度均下降了约62%,说明重庆市主城区的热力景观总体上呈聚集化,连通性较强。③NDVI和DEM与LST呈负相关,NDBI与LST呈正相关,影响程度为NDBI>NDVI>DEM。

北京城市副中心及周边区域蓝绿空间景观格局及降温效应评估

科学评估北京城市副中心及周边区域建设不同阶段景观格局和热环境,对其今后的发展规划和相关政策制定具有重要意义。以北京城市副中心外围规划为基准稍作调整作为研究区,选取2016年、2018年、2020年和2022年共4期资源三号遥感影像数据,以及Google Earth Engine(GEE)中4年6月1日-9月30日的Landsat 8遥感影像数据,通过面向对象分类、地表温度反演、相关性分析方法定量分析不同时期的蓝绿空间景观格局以及蓝绿空间的降温效应。结果表明:(1)2016-2022年,研究区蓝空间的面积占比在保持稳定的同时逐渐增加,绿空间的面积占比先减少后增加;(2)2016-2022年,北京城市副中心及周边区域蓝绿空间景观格局中各斑块类型在景观中的分布越来越均衡;(3)2016-2022年间,地表温度均值呈“上升—下降—上升”的波动变化,蓝空间的地表温度最低,其次是绿空间,蓝空间和绿空间在一定程度上起到降温的作用;(4)提高聚集度、减少人类活动的割裂程度、减小空间破碎度均可提升蓝绿空间的降温效应。总体而言,北京城市副中心及周边区域建设使得蓝绿空间面积增加,景观格局分布更加均衡,蓝绿空间的降温效果较为明显。

C1单元沙二段开发井网完善优化研究

针对C1单元沙二段储层薄、地层压力低、部分区域井网仍不完善的问题,本文通过建立数值模拟模型,模拟C1单元沙二段2、3号小层未控制区域,优化布井原则,完善该区域井网;优化开发方式,调整注入成分的用量,改善已动用区块的开发效果。数值模拟结果表明:布井厚度为3.2m以上,边部井纵向上位于储层下部最优,而内部井纵向上位于储层上部最优,距边水距离要大于180 m,井水平段长度应该在180 m左右,蒸汽吞吐前期注汽强度为10 t/m左右,蒸汽吞吐后期注汽量应逐周期增加5%;目前情况下,前置N2增能防窜+伴注N2扩大蒸汽波及体积效果最好,最优用量为前置N26万m^(3)+伴注N26万m^(3)。根据现场应用结果,新布井网单井产油为11.5 t/d,比老井网单井产油量增加6.59t/d,为其他区块后续开发提供了经验借鉴。

Influence of the Tibetan Plateau on the Summer Climate Patterns over Asia in the IAP/LASG SAMIL Model

A series of numerical experiments are carried out by using the Spectral Atmospheric Model of State Key Laboratory of Numerical Modeling Atmospheric Sciences and Geophysical Fluid Dynamics/Institute of Atmospheric Physics （SAMIL） to investigate how the Tibetan Plateau （TP） mechanical and thermal forcing affect the circulation and climate patterns over subtropical Asia. It is shown that, compared to mechanical forcing, the thermal forcing of TP plays a dominant role in determining the large-scale circulation in summer. Both the sensible heating and the latent heating over TP tend to generate a surface cyclonic circulation and a gigantic anticyclonic circulation in the mid- and upper layers, whereas the direct effect of the latter is much more significant. Following a requirement of the time-mean quasi-geostrophic vorticity equation for large-scale air motion in the subtropics, convergent flow and vigorous ascending motion must appear to the east of TP. Hence the summer monsoon in East China is reinforced efficiently by TP. In contrast, the atmosphere to the west of TP is characterized by divergent flow and downward motion, which induces the arid climate in Mid-Asia.

DISTRIBUTION PATTERNS OF LEAF AREA INDEX FOR MAJOR CONIFEROUS FOREST TYPES IN CHINA

Leaf area index (LAI) of natural vegetation is recognized as the most important variable for measuring vegetation structure over large areas, and for relating it to energy and mass exchange, which has been successfully estimated from satellite resolution sensors. In this paper, according to the statistical analysis based on a lot of forest plots, the mathematical models of LAI distribution patterns in the hydro thermal spaces for five coniferous forest types in China were established. For the cold temperate larch forests growing in the dry and cold climate, their LAI increases with the increasing of warm index and precipitation in the way of hyperbolic quadratic surface. For the cold temperate spruce fir forests and temperate Pinus tabulaeformis forests, their LAI is negatively related to the annual mean air temperature in the way of the natural exponential curve, in order to adapt to the water oppressed environments. For the subtropical Pinus massoniana forests and Cunninghamia lanceolata forests growing in the warm and moist climate, their LAI is related to the annual mean air temperature in the way of the parabolic quadratic curve.

气候适应性视角下传统村落空间格局分析——以南京市江宁区黄龙岘村为例

在乡村振兴背景下,对传统村落进行微气候和舒适度研究有利于保护传统村落的空间肌理和建设生态宜居的美丽乡村。以南京市江宁区黄龙岘村为对象,基于实地测量,针对庭院空间、街巷空间、滨水空间、休闲空间的微气候因子和可视因子开展定量研究,运用RayMan计算生理等效温度(PET),以PET量化各空间的客观热舒适度,结合问卷调查,分析人的主观热感受,通过主客观结合的方式研究微气候因子与人体热舒适度的相关性。结果表明,PET与空气温度呈显著正相关,与相对湿度呈显著负相关,相关性次于空气温度,与瞬时风速的相关性较弱。在此基础上,综合传统村落的空间格局,比较4种空间类型的气候条件,量化不同空间类型的热舒适性,并提出改造策略,以期为不同地区传统村落的空间设计提供新思路。

校园庭园户外遮阳对夏季热舒适的影响

探究寒冷干旱地区庭园室外空间设计中的遮阳效应对行人热舒适的影响机制,为建筑师优化室外空间形态设计、调控室外热环境、促进公共活动提供依据。以兰州理工大学典型庭园——槐园为例,通过对庭园空间测绘、室外空间形态类型解析、室外微气候实测、室外热舒适计算,并进行相关性分析,研究庭园空间形态指标与室外微气候要素和人体热舒适指标的耦合关系。结果显示:室外空间形态的覆盖要素指标天穹可见度(SVF),围合要素指标界面通透度(WSP)对夏季庭园室外微气候的空气温度影响显著,进而影响室外热舒适指标。因此,寒冷干旱地区庭园室外空间设计中,可以利用遮阳效应和通风效应优化建筑与植物、水体景观组合的空间形态,以此调控室外微气候并促进室外热舒适。

缓解城市热环境的多层级“源-汇”景观网络构建

以天津市六区和新四区为研究对象,首先运用形态学空间格局分析获得7种景观类型,从中提取稳定性较好、面积较大、连通性较高、热贡献度显著的核心区斑块为中心“源”“汇”;其次使用6个空间数据指标构建热环境格局评价模型,根据2009—2013、2013—2018年热环境格局的变化情况提出4类修正系数对基本阻力面进行修正;最后利用“源-源”、“汇-汇”、“源-汇”廊道构建能体现“补偿-输送-作用”过程的多层级“源-汇”景观网络。结果表明:(1)提取的Ⅰ、Ⅱ类中心“源”共27个,总面积为22773 hm^(2);中心“汇”共23个,总面积为50732 hm^(2)。中心“源”的整体抗干扰能力较小,容易受到种植类型和水体富营养化的影响。(2)多层级“源-汇”景观网络总长度约为1445 km,新四区的廊道占总廊道的70%。廊道在空间上分布不均,津南区分布稀疏,北辰区和市六区分布密集。(3)能量从中心“源”逐渐向中心“汇”流动的过程,可揭示网络之间的层级关系和各级廊道对热环境气候的调控作用。以生态格局与过程的角度构建缓解城市热环境的多层级“源-汇”景观网络体系,对合理规划廊道建设、高效缓解城市热环境效应具有积极意义。

南京主城区蓝绿空间格局对降温效益的影响及其协同作用研究

高密度城市中的绿色与蓝色空间具有降低地表温度、缓解热岛效应的功能,两者有着相互促进的协同作用。城市蓝绿空间的格局是影响其降温效益的主要因素之一。以南京主城区为例,选取17个空间格局指标,分别从面积—边缘、形状、核心、聚散度4类表征城市绿色空间、蓝色空间与蓝绿空间格局特征,对比分析三者与地表温度的关联性,探讨绿色与蓝色空间对降温的协同促进作用。结果表明:(1)城市蓝绿空间格局对其降温效益的影响不具有季节性差异;(2)蓝绿空间格局整体性指标相较于单一绿色空间与蓝色空间格局指标,对地表温度产生的影响更加显著;(3)增加斑块面积、提升形状复杂度、减小空间破碎度均可促进城市蓝绿空间的降温效益。从整体性与协同性的角度探索了城市蓝绿空间格局对降温效应的影响,阐明了城市蓝绿空间统筹调控的必要性,有助于实现高密度城市规划实践中蓝绿空间格局的系统性优化与精细化调控,推动城市蓝绿空间融合发展。