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Enhanced Cooling Efficiency of Urban Trees on Hotter Summer Days in 70 Cities of China
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作者 Limei YANG Jun GE +4 位作者 Yipeng CAO Yu LIU Xing LUO Shiyao WANG Weidong GUO 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第11期2259-2275,共17页
Increasing the urban tree cover percentage(TCP) is widely recognized as an efficient way to mitigate the urban heat island effect. The cooling efficiency of urban trees can be either enhanced or attenuated on hotter d... Increasing the urban tree cover percentage(TCP) is widely recognized as an efficient way to mitigate the urban heat island effect. The cooling efficiency of urban trees can be either enhanced or attenuated on hotter days, depending on the physiological response of urban trees to rising ambient temperature. However, the response of urban trees' cooling efficiency to rising urban temperature remains poorly quantified for China's cities. In this study, we quantify the response of urban trees' cooling efficiency to rising urban temperature at noontime [~1330 LT(local time), LT=UTC+8] in 17summers(June, July, and August) from 2003–19 in 70 economically developed cities of China based on satellite observations. The results show that urban trees have stronger cooling efficiency with increasing temperature, suggesting additional cooling benefits provided by urban trees on hotter days. The enhanced cooling efficiency values of urban trees range from 0.002 to 0.055℃ %-1 per 1℃ increase in temperature across the selected cities, with larger values for the lowTCP-level cities. The response is also regulated by background temperature and precipitation, as the additional cooling benefit tends to be larger in warmer and wetter cities at the same TCP level. The positive response of urban trees' cooling efficiency to rising urban temperature is explained mainly by the stronger evapotranspiration of urban trees on hotter days.These results have important implications for alleviating urban heat risk by utilizing urban trees, particularly considering that extreme hot days are becoming more frequent in cities under global warming. 展开更多
关键词 urban trees cooling efficiency China's cities EVAPOTRANSPIRATION SUMMER hot days
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Changes of heating and cooling degree days over China in response toglobal warming of 1.5℃, 2℃, 3℃ and 4℃ 被引量:8
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作者 SHI Ying ZHANG Dong-Feng +1 位作者 XU Ying ZHOU Bo-Tao 《Advances in Climate Change Research》 SCIE CSCD 2018年第3期192-200,共9页
Future changes of heating degree days (HDD) and cooling degree days (CDD) in the 21st century with and without considering populationfactor are investigated based on four sets of climate change simulations over Ea... Future changes of heating degree days (HDD) and cooling degree days (CDD) in the 21st century with and without considering populationfactor are investigated based on four sets of climate change simulations over East Asia using the regional climate model version 4.4 (RegCM4.4)driven by the global models of CSIRO-Mk3-6-0, EC-EARTH, HadGEM2-ES, and MPI-ESM-MR. Under global warming of 1.5℃, 2℃, 3℃,and 4℃, significant decrease of HDD can be found over China without considering population factor, with greater decrease over high elevationand high latitude regions, including the Tibetan Plateau, the northern part of Northeast China, and Northwest China; while population-weightedHDD increased in areas where population will increase in the future, such as Beijing, Tianjin, parts of southern Hebei, northern Shandong andHenan provinces. Similarly, the CDD projections with and without considering population factor are largely different. Specifically, withoutconsidering population, increase of CDD were observed over most parts of China except the Tibetan Plateau where the CDD remained zerobecause of the cold climate even under global warming; while considering population factor, the future CDD decreases in South China andincreases in North China, the Sichuan Basin, and the southeastern coastal areas, which is directly related to the population changes. The differentfuture changes of HDD and CDD when considering and disregarding the effects of population show that population distribution plays animportant role in energy consumption, which should be considered in future research. 展开更多
关键词 REGIONAL CLIMATE model Global WARMING of 1.5 2℃ 3℃ and 4℃ Heating degree dayS cooling degree dayS China
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Degree-Day Analysis for Different Locations in Turkey and Effect on Architecture Conceptualism
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作者 Hasan Sehmuz Hastemoglu Ilker Erkan 《Journal of Civil Engineering and Architecture》 2015年第10期1252-1260,共9页
Energy analysis plays an important role in developing an optimum and cost effective design of HVAC (heating, ventilating and air conditioning) system for an architecture. Although there are different energy analysis... Energy analysis plays an important role in developing an optimum and cost effective design of HVAC (heating, ventilating and air conditioning) system for an architecture. Although there are different energy analysis methods, which vary in complexity, the degree-day methods are the simplest methods and well-established tools. Energy consumption increases as the number of heating and cooling degree days increases and falls as the number of heating and cooling degree days falls. The value of degree days is a measure which can be used to indicate the demand for energy to heat or cool buildings and spaces. The monthly or annual cooling and heating requirements of specific buildings in different locations can be estimated by means of the degree-day concept. The base temperature is the outdoor temperature below or above which heating or cooling is needed. In this study, the degree days for the period of 2008-2012 were calculated for Turkey (10 cities) and also to develop new software for easy analysis about cooling degree days. This paper can be helpful for designing facade and also contribute to degree-day analyses. 展开更多
关键词 cooling degree days Turkish architecture building energy conservation.
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Estimate the Emergence of Pectinophora gossypiella Saunders, (Lepidoptera: Gelechiidae) with Degree Days in the Region of Thessaly, Greece
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作者 S. V. Leontopoulos I. K. Vagelas F. T. Gravanis 《Journal of Agricultural Science and Technology(A)》 2011年第2X期182-186,共5页
The pink bollworm (Pectinophora gossypiella), is one of the most damaging pests_of cotton growing in the region of Thessaly in Greece. The time of exit of the adults in spring is an important factor that affects the... The pink bollworm (Pectinophora gossypiella), is one of the most damaging pests_of cotton growing in the region of Thessaly in Greece. The time of exit of the adults in spring is an important factor that affects the infestation index in the crop during the summer. Mathematical models by Sevacherian & El-Zik, and Huber, which were implemented in California, were used in this study to determine the beginning, the peak of the adults output and the end of them during the summer. A data comparison between California and region of Thessaly were applied since California and Thessaly are on the same latitude with similar meteorological conditions. The results showed that the emergence occurs when the insect completes 259 DD according to the method described by Sevacherian & EI-Zik, while according to the method described by Huber 430-454 DD are needed. It was observed that either according to the method described by Sevacherian and El-Zik or according to the method described by Huber, the values (DD) showed that the appearance of adults varies between -262 DD to 59 DD and -872 DD to 115 DD respectively. 展开更多
关键词 Pink bollworm Pectinophora gossypiella degree days insect emergence.
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Estimation of Accumulated Degree Day Value of Six Landmarks within the Pupal Stage of Lucilia sericata
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作者 Annalisa Grisendi Francesco Defilippo +2 位作者 Fabio Gatti Michele Dottori Paolo Bonilauri 《Journal of Life Sciences》 2015年第7期311-317,共7页
The present paper investigates the pupal development times ofLucilia sericata which were studied in the laboratory at six different constant temperatures (20, 22, 24, 26, 28 ℃ each ± ℃). Lower thresholds (tL... The present paper investigates the pupal development times ofLucilia sericata which were studied in the laboratory at six different constant temperatures (20, 22, 24, 26, 28 ℃ each ± ℃). Lower thresholds (tL) for development were estimated from the linear regression of the developmental rates on each temperature. These data have made it possible to calculate the ADD (Accumulated Degree-Days) necessary for L. sericata to complete the larval stage and to achieve adult emergence. The minimal duration of development from oviposition to adult emergence was found to be inversely related to temperature. Additionally, six landmarks in pupal development are showed and for each of the landmarks the ADD value was calculated for every rearing temperature involved. These data assist in calculating the duration of the pupal stage based on morphological characteristics and would be of great value for future forensic entomological casework. 展开更多
关键词 Forensic science forensic entomology Lucilia sericata pupal landmarks accumulated degree day post-morteminterval.
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Optimizing Eastern Gamagrass Forage Harvests Using Growing Degree Days
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作者 Tim L. Springer Stacey A. Gunter +1 位作者 Jason J. Goldman Corey A. Moffet 《Agricultural Sciences》 2016年第10期710-715,共7页
Tripsacum dactyloides (L.) L., commonly known as eastern gamagrass, is useful for grazing, stored forage, soil amelioration and conservation, and as a biofuel feedstock. Our goal was to calculate accumulated growing d... Tripsacum dactyloides (L.) L., commonly known as eastern gamagrass, is useful for grazing, stored forage, soil amelioration and conservation, and as a biofuel feedstock. Our goal was to calculate accumulated growing degree days (GDD) from existing datasets collected for eastern gamagrass forage production experiments in northwestern Oklahoma, and discuss the use of GDD, instead of calendar harvest dates, in the production of eastern gamagrass forage. Growing degree days were calculated from 1 January each year using the “optimum day method”. For 10 harvest years, the first eastern gamagrass harvest required 690 ± 26 cumulative GDD. Based on long-term weather data from Woodward, Oklahoma, this would place the first harvest on or near 1 June. The second harvest required 635 ± 27 cumulative GDD which would place the second harvest on or near 15 July and the third harvest required 690 ± 23 cumulative GDD placing it on or near 30 August. Each of the 30 harvest required an average of 670 ± 15 cumulative GDD. Using GDD to predict harvest events is a useful tool that forage producer can use in the production of eastern gamagrass forage in the USA and possibly elsewhere. 展开更多
关键词 Eastern Gamagrass Tripsacum dactyloides Growing degree days
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Experimental and clinical research of application of plasma cool sediment in treatment of Traumatic surface of deep degree burn
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《中国输血杂志》 CAS CSCD 2001年第S1期398-,共1页
关键词 DEEP Experimental and clinical research of application of plasma cool sediment in treatment of Traumatic surface of deep degree burn
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The Influence of Urbanization on Cooling Energy Consumption in Xi'an
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作者 Shen Jiaojiao Hao Yu +1 位作者 Lu Shan Zhang Hongfang 《Meteorological and Environmental Research》 CAS 2018年第1期25-29,共5页
Based on data of daily air temperature during 1951-2013,long-term variation characteristics of cooling degree days( CDD) in Xi'an and Chang'an in summer were analyzed by using CDD to evaluate cooling energy consum... Based on data of daily air temperature during 1951-2013,long-term variation characteristics of cooling degree days( CDD) in Xi'an and Chang'an in summer were analyzed by using CDD to evaluate cooling energy consumption and 26 ℃ as the basic temperature of CDD. The results indicated that the changing trends of CDD in Xi'an and Chang'an were basically identical within a year,and the demand for cooling refrigeration was large mainly from June to August,especially in July. The maximum of urban-rural difference of CDD between Xi'an and Chang'an appeared in June.In order to achieve the same temperature,energy needed by the urban area was 5-7 ℃·d more than the suburb from June to August. Temperature and the cooling energy consumption were closely related,and the correlation degree increased with the rise of temperature. The effects of temperature increase of 1 ℃ on cooling energy consumption rate in Xi'an were more obvious than that in Chang'an. In both Xi'an and Chang'an,the effects of temperature increase of 1 ℃ on cooling energy consumption rate in July and August were greater than that in May,June and September.Evaluation models of cooling energy consumption in summer in Xi'an and Chang'an were built using temperature anomaly and CDD variability and can be applied to business systems. 展开更多
关键词 Temperature change cooling degree days (CDD) cooling energy consumption Evaluation model URBANIZATION
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隧道火灾中细水雾降温消烟数值模拟研究
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作者 牛奕 黄钦 袁满 《武汉理工大学学报(信息与管理工程版)》 CAS 2024年第1期28-34,共7页
细水雾系统因其良好的控烟作用在隧道火灾中得到广泛应用。基于气溶胶动力学机理提出细水雾降温消烟数值模型,通过模拟狭长通道细水雾阻烟实验验证其有效性。为探究细水雾粒径、雾化锥角、细水雾与排烟口间距对降温消烟效果的影响规律,... 细水雾系统因其良好的控烟作用在隧道火灾中得到广泛应用。基于气溶胶动力学机理提出细水雾降温消烟数值模型,通过模拟狭长通道细水雾阻烟实验验证其有效性。为探究细水雾粒径、雾化锥角、细水雾与排烟口间距对降温消烟效果的影响规律,进一步采用该模型开展细水雾系统在大尺度隧道火灾中降温消烟效果研究。研究表明:细水雾液滴粒径越小,降温消烟效果越好,且消烟效率与粒径成反比,但当粒径小于100μm时,因液滴蒸发导致消烟效率有所降低;雾化锥角在60°时消烟效果最好,雾化锥角增大或减小都会降低细水雾系统的消烟效果;当细水雾系统与排烟系统间距较小时,由于细水雾液滴会被排烟系统抽出,导致消烟效果减弱,因此两者间距越大,消烟效果越好。 展开更多
关键词 隧道火灾 细水雾 数值模拟 降温消烟 遮光度
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全球气温–相对湿度–人口驱动型制冷度日数时空演变、影响因素及模拟
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作者 李元征 王怡君 +3 位作者 赵国松 贺添 王昉琳 孙永胜 《地理科学》 CSSCI CSCD 北大核心 2024年第8期1406-1416,共11页
制冷度日数(Cooling degree days,CDDs)可指示空间制冷能耗与室外热环境,但在全球栅格尺度上同时考虑气温、相对湿度与人口的CDDs分析鲜见报道。据此,本文利用气象、人口、遥感等数据,曼−肯德尔法、相对重要性分析、机器学习等方法在全... 制冷度日数(Cooling degree days,CDDs)可指示空间制冷能耗与室外热环境,但在全球栅格尺度上同时考虑气温、相对湿度与人口的CDDs分析鲜见报道。据此,本文利用气象、人口、遥感等数据,曼−肯德尔法、相对重要性分析、机器学习等方法在全球0.25°栅格尺度上开展气温−相对湿度−人口驱动型CDDs时空变化、影响因素与模拟研究。结果表明,①全球基于湿球温度计算的CDDs(CDDs_(wb),CDDs based on wet bulb temperature)在30°N~30°S间除北非与西亚外的不少地区均高于567(℃·d),极高值[1469~2677(℃·d)]主要分布在亚马孙平原、东南亚中南半岛南侧及其以南地区。基于湿球温度与人口计算的CDDs(CDDs based on wet bulb temperature and population,CDDs_(wb_pop))大多低于17×10^(6)(℃·d·人),高值[277×10^(6)~2144×10^(6)(℃·d·人)]主要在恒河平原与印度南端、尼日利亚沿海、越南南北平原与爪哇岛。②1970—2018年CDDs_(wb)与2000—2018年CDDs_(wb_pop)在中高纬度呈现极高年际间变异,全球未来变化趋势多与过去保持强一致性。CDDs_(wb)显著增加(P<0.05)地区主要分布在北非与西亚、澳大利亚、里海东部、印尼西部的一些地区,显著降低区域主要分布在拉美、撒哈拉以南非洲、中国胡焕庸线以南及中南半岛的一些地区。CDDs_(wb_pop)在一些地区显著增加,速率基本小于8×10^(6)(℃·d·人)/a,集中发布在北非、西亚与里海东部的一些地区。③纬度与高程均分别与CDDs_(wb)及其变异系数呈现显著负向与正向偏相关关系(P<0.05);在不同大洲内,年降水量、夏季反照率、增强型植被指数与PM_(2.5)对CDDs_(wb)影响不同,夜间灯光影响不大。CDDs_(wb)实际值与模拟值间R2大多高于0.935,平均绝对误差百分比多小于6.77%,均方根误差在15.63~184.51(℃·d)。 展开更多
关键词 制冷度日数 相对湿度 人口加权 PM_(2.5) 广义回归神经网络
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高温-冷却-冲击循环下花岗岩物理损伤及力学劣化试验研究
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作者 詹金武 周亚来 +2 位作者 王雨 黄明 江松 《岩土力学》 EI CAS CSCD 北大核心 2024年第8期2362-2372,2386,共12页
高温岩石经不同冷却方式冷却后的力学特性直接影响着深地岩土工程施工的安全性。以中风化花岗斑岩为研究对象,对400℃下循环自然冷却和遇水冷却试样展开单轴压缩试验和循环动态冲击试验,对比分析花岗岩力学性质的变化规律,并基于Logisti... 高温岩石经不同冷却方式冷却后的力学特性直接影响着深地岩土工程施工的安全性。以中风化花岗斑岩为研究对象,对400℃下循环自然冷却和遇水冷却试样展开单轴压缩试验和循环动态冲击试验,对比分析花岗岩力学性质的变化规律,并基于Logistic分布规律,引入受荷损伤变量和热循环损伤变量建立花岗岩统计损伤本构模型,确定了相应参数表达式,验证了本构模型的适用性与合理性,结果表明:在单轴压缩试验中,随着热循环次数的提高,花岗岩内部微裂隙开始扩展、贯通形成宏观裂纹,岩样质量和纵波波速开始衰减,静态应力-应变曲线中的弹性变形阶段逐渐缩短,出现明显的不稳定破坏阶段;冷却方式可以显著影响岩石强度的劣化速度,但对花岗岩的最终静态抗压强度无明显影响。在0.30 MPa冲击气压下,随着冲击次数的增加,自然冷却花岗岩的动态抗压强度先增大后减小,首次冲击可有助于提高自然冷却花岗岩的抗压强度,当热循环超过3次时,花岗岩的抗循环冲击能力开始下降。基于Logistic分布建立的动态损伤本构模型与试验曲线具有较好的一致性,且模型参数获取简单,物理意义明确,具有一定适用性。研究成果可为变温环境下岩体施工、修复及围岩稳定性分析提供参考。 展开更多
关键词 高温岩石 自然冷却 遇水冷却 多次冲击 损伤程度
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NEPE推进剂固化降温过程残余应力应变分析
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作者 周东谟 谢旭源 +2 位作者 王瑞民 刘向阳 惠步青 《含能材料》 EI CAS CSCD 北大核心 2024年第2期193-203,共11页
为研究硝酸酯增塑聚醚(NEPE)推进剂药柱固化与降温过程中残余应力/应变的形成机制,基于ABAQUS有限元软件对推进剂在固化与降温过程中的温度场、固化度场和应力/应变场进行数值分析。结果表明,NEPE推进剂药柱在50℃高温固化过程中,药柱... 为研究硝酸酯增塑聚醚(NEPE)推进剂药柱固化与降温过程中残余应力/应变的形成机制,基于ABAQUS有限元软件对推进剂在固化与降温过程中的温度场、固化度场和应力/应变场进行数值分析。结果表明,NEPE推进剂药柱在50℃高温固化过程中,药柱内部存在温度梯度与固化速率梯度,药柱截面中心位置温度与固化速率较高,但在固化完成时内部固化度趋于一致,药柱内部的温差不会影响药柱最终的残余应力和残余应变;NEPE推进剂药柱在固化与降温2个阶段中,总残余应力/应变基本符合应力/应变叠加原理,药柱的残余应力/应变主要由固化收缩应力/应变与降温过程产生热应力/应变构成,总残余应力在这两阶段占比分别约为20%与80%,总残余应变占比分别约为30%与70%;本方法获得的残余应力/应变与传统采用温度折算方法计算结果分布趋势基本一致,但计算结果整体偏小。 展开更多
关键词 硝酸酯增塑聚醚(NEPE)推进剂 温度场 固化度场 固化降温 残余应力
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基于PYTHON的城市人为热通量与温度关系分析及风险评估 被引量:1
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作者 龚泽瀚 《科技资讯》 2024年第6期238-246,共9页
针对全球城市热岛效应日趋严重而复杂形势,提出了一种运用SUEWS模型和Python进行数据分析的方法,探讨人为热通量影响城市热岛效应的重要性与形成机理,重点分析温度变化对制冷度日和人为热通量的影响程度。通过对城市气候大数据的分析研... 针对全球城市热岛效应日趋严重而复杂形势,提出了一种运用SUEWS模型和Python进行数据分析的方法,探讨人为热通量影响城市热岛效应的重要性与形成机理,重点分析温度变化对制冷度日和人为热通量的影响程度。通过对城市气候大数据的分析研究,发现制冷度日和人为热通量之间存在一定相关性,人为热通量与温度变化之间有敏感响应关系;最后提出相应建议和措施。 展开更多
关键词 城市热岛效应 人为热通量 温度敏感性 制冷度日
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Introducing Degree Days to Building Thermal Climatic Zoning in China 被引量:1
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作者 LIU Yan WEN Zeqiu +4 位作者 LYU Kailin YANG Liu LIU Jiaping DONG Hong GAO Qinglong 《Journal of Thermal Science》 SCIE EI CAS CSCD 2023年第3期1155-1170,共16页
Building thermal climatic zoning is a key issue in building energy efficiency.Heating degree days(HDD) and cooling degree days(CDD) are often employed as indexes to represent the heating and cooling energy demand in c... Building thermal climatic zoning is a key issue in building energy efficiency.Heating degree days(HDD) and cooling degree days(CDD) are often employed as indexes to represent the heating and cooling energy demand in climatic zoning.However,only using degree days may oversimplify the climatic zoning in regions with complex climatic conditions.In the present study,the application of degree days to current building thermal climatic zoning in China was assessed based on performance simulations.To investigate the key indexes for thermal climatic zoning,the climate characteristics of typical cities were analyzed and the relationships between the climate indexes and heating/cooling demand were obtained.The results reveal that the annual cumulative heating load had a linear correlation with HDD 18 only in regions with small differences in altitude.Therefore,HDD is unsuitable for representing the heating demand in regions with large differences in altitude.A comprehensive index(winter climatic severity index) should be employed instead of HDD,or complementary indexes(daily global solar radiation or altitude) could be used to further divide climate zones.In the current official climatic zoning,the base temperature of 26℃ for CDD is excessively high.The appropriate base temperature range is 18℃ to 22℃.This study provides a reference for selecting indexes to improve thermal climatic zoning in regions with similar climates. 展开更多
关键词 climatic zoning degree days building thermal design base temperature solar radiation
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基于工业园区的电碳模型研究
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作者 汪海良 《建筑电气》 2024年第7期3-6,共4页
利用STL(Seasonal-Trend decomposition using Loess,时间序列分解算法)模型对工业园区运行阶段的建筑碳排放进行预测分析,介绍电碳模型构建技术路线、模型构建的STL和线性回归,给出某高新园区2021年到2022年碳排放量的预测结果。可为... 利用STL(Seasonal-Trend decomposition using Loess,时间序列分解算法)模型对工业园区运行阶段的建筑碳排放进行预测分析,介绍电碳模型构建技术路线、模型构建的STL和线性回归,给出某高新园区2021年到2022年碳排放量的预测结果。可为园区规划双碳路径、制定减排计划、开展节能减排手段提供数据支撑,辅助园区实现绿色低碳发展目标。 展开更多
关键词 工业园区 建筑碳排放 碳排放预测模型 冷却度日 STL 线性回归 算法 拟合
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冷藏/冷冻车辆用制冷机组的性能实验及模拟
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作者 王振环 崔然成 王珊珊 《制冷学报》 CAS CSCD 北大核心 2024年第1期129-136,共8页
为研究冷藏/冷冻车辆用10 kW制冷机组不同参数对性能的影响,本文采用实验和模拟方法分析了制冷循环系统的制冷能力、COP和压力性能,并通过分别改变制冷剂充注量、过热度和制冷剂种类对其进行了实验和模拟研究。结果表明:随着制冷剂充注... 为研究冷藏/冷冻车辆用10 kW制冷机组不同参数对性能的影响,本文采用实验和模拟方法分析了制冷循环系统的制冷能力、COP和压力性能,并通过分别改变制冷剂充注量、过热度和制冷剂种类对其进行了实验和模拟研究。结果表明:随着制冷剂充注量和过热度的变化,制冷机组的制冷能力和COP表现出不同的趋势。模拟值和实验值的制冷能力和COP误差分别为6.4%和8.5%,所有结果均在10%以内。与制冷剂充注量相比,制冷机组的性能变化更多地依赖于过热度的变化。在制冷循环过热度为4℃、制冷剂充注量为7.4 kg时,制冷机组的制冷能力和COP最佳。通过数值模拟分析了应用于制冷循环系统的制冷剂R449A,比采用R404A的系统COP高约4%。确认了制冷剂R449A可以替代R404A使用。 展开更多
关键词 冷藏车 制冷机组 制冷能力 过热度 COP R449A
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不同开度可调涡轮导叶前缘气膜冷却效果研究
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作者 靳合龙 白晓辉 +3 位作者 张振华 李鹏刚 陈磊 刘存良 《燃气涡轮试验与研究》 2024年第2期19-28,共10页
针对变循环发动机的可调低压涡轮导叶开展了不同开度下的前缘气膜冷却效果研究。采用数值仿真的方法,研究了5种典型导叶开度下的导叶表面压力系数分布规律,探究了开度与冷气吹风比对叶片前缘气膜出流特性和覆盖特性的影响规律。结果表明... 针对变循环发动机的可调低压涡轮导叶开展了不同开度下的前缘气膜冷却效果研究。采用数值仿真的方法,研究了5种典型导叶开度下的导叶表面压力系数分布规律,探究了开度与冷气吹风比对叶片前缘气膜出流特性和覆盖特性的影响规律。结果表明:导叶开度的减小导致前缘的气动驻点位置向压力面方向移动,造成前缘冷气射流更多地流向吸力面侧,使吸力面气膜冷却效率提高;此外,导叶开度的减小导致吸力面与压力面的冷气贴壁效果都有提高,但两者的具体机理不同。导叶开度的变化对前缘气膜孔最佳吹风比影响较小,不同开度下的最佳吹风比都在1.0附近。由于导叶开度为0°时滞止线位于气膜孔排4之上,堵塞效应显著,与开度为5°、−5°条件相比,面平均气膜冷却效率降低了13.6%。 展开更多
关键词 变循环发动机 可调低压涡轮导叶 气膜冷却 导叶开度 吹风比
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Cool water brought by upwelling in the Sanya Bay benefits corals in the background of global warming
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作者 YANG Dingtian 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2017年第3期14-19,共6页
It has been reported that global warming has negative effects on coral ecosystems in the past 50 years and the effects vary in different ocean environment. In order to make clear the coral reef status in the backgroun... It has been reported that global warming has negative effects on coral ecosystems in the past 50 years and the effects vary in different ocean environment. In order to make clear the coral reef status in the background of global warming along the south coast of Hainan Island of China, satellite and in situ data are used to retrieve the information of the coral reef status and surrounding environmental factors. The results show that cool water induced by upwelling along the south coast of Hainan Island is found in the area every summer month, especially in the relatively strong El Ni?o years(2002–2003 and 2005). From the NOAA satellite data, degree heating week(DHW) index does not exceed 3 in Sanya Bay even in the relatively strong El Ni?o years. By comparison of a coral reef growth rate in the Sanya Bay with respect to El Ni?o events from 1957 to 2000, coral's growth rate is relatively greater during 1972, 1991–1994 and 1998 El Ni?o event. By analyzing the environmental factors, it is found that the cool water induced by upwelling may be the main reason for protecting corals from global warming effects. 展开更多
关键词 cool water upwelling corals degree heating week Sanya Bay
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面向功能分区的大型商场建筑冷负荷预测方法 被引量:2
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作者 赵安军 杨航杰 +2 位作者 荆竞 张萌芝 焦阳 《重庆大学学报》 CAS CSCD 北大核心 2023年第6期61-75,共15页
针对大型商场面向建筑整体冷负荷预测不能为商场各区域按需供冷提供合理控制策略的问题,通过研究商场不同区域冷负荷特点,采用灰色关联度分析法筛选影响商场不同区域冷负荷的关键影响因素,针对实际情况中各输入特征对冷负荷影响程度的... 针对大型商场面向建筑整体冷负荷预测不能为商场各区域按需供冷提供合理控制策略的问题,通过研究商场不同区域冷负荷特点,采用灰色关联度分析法筛选影响商场不同区域冷负荷的关键影响因素,针对实际情况中各输入特征对冷负荷影响程度的不稳定性,提出了基于双重注意力机制和LSTM的短期分区冷负荷预测模型。LSTM网络充分考虑空调冷负荷与相关特征变量之间的非线性关系,特征注意力自主分析历史信息和输入变量之间的关系,提取重要特征,时序注意力选取LSTM网络关键时刻的历史信息,提升较长时间段预测效果的稳定性。以西安某大型商场建筑的冷负荷数据集为实验数据,实验结果表明所提模型相比于LSTM模型、CNN-LSTM模型和Attention-LSTM模型,误差指标MAPE和RMSE均有显著降低,R^(2)明显增加且稳定0.99以上,具有较好的泛化能力和较强的稳定性。 展开更多
关键词 功能分区 灰色关联度 冷负荷预测 注意力机制 长短记忆神经网络
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Q355B板坯纵裂缺陷机理研究与控制实践 被引量:1
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作者 李亮 李晓冬 金柱元 《山西冶金》 CAS 2023年第11期115-117,共3页
针对国内某钢厂企业Q355B铸坯裂纹产生原因进行分析,并对炼钢成分控制、连铸过热度、拉速、锥度等工艺参数进行优化,解决了连铸坯纵裂纹问题,降低了炼钢废次降,可为相关企业减少Q355B连铸坯纵裂纹提供一定的理论和实践指导。
关键词 纵裂 成分 过热度 拉速 二次冷却
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