1960~2013年我国霾污染的时空变化

利用近54年（1960～2013年）我国霾日以及一些相关气象要素的观测资料,采用气候倾向估计、聚类分析、累积距平和突变检验等多种方法,分析了我国霾日数变化特征.结果表明：我国的霾污染主要发生在中东部和南部,尤以北京、山西中部和南部、河南局部地区、长江三角洲和珠江三角洲等地最为严重,我国西部和东北部地区相对较少.霾日发生的频率总体呈增加的趋势,而且与能源消耗总量有很好的正相关关系.我国霾日数的增加除了依赖于污染源排放加剧外,不利的气候条件加剧了霾天气的发生.近54年降水日数、平均风速、日照时数和相对湿度与霾日数的相关系数分别为-0.653、-0.635、-0.462和-0.699,远远超出了99.9%的信度检验标准.聚类分析表明,上升极显著、上升显著和上升明显的站点年平均霾日数近年来均有加速上升的趋势,其累积距平的变化趋势为下降-平缓-上升型.轻微上升站点上升时期为20世纪60年代至70年代末与2000年之后,累积距平为多波动型.轻微下降与下降明显的站点快速上升时期为60年代至70年代末,随后均有不同程度的下降,累积距平呈上升-平缓-下降型,且在1992～1993年间霾日数发生了由多到少的突变.     

环境适应性要求在型号中应用问题分析

针对航空装备环境鉴定试验大纲审查中暴露的研制总要求或成品技术协议书中对"使用环境"、"环境要求"表述方面的问题,阐述了环境适应性要求的内涵和合理的表征方法,分析了目前型号中"使用环境"和"环境要求"等概念的不完整性及其带来的一些副作用,提出了使用方和型号总师单位应尽快理解和掌握有关标准中环境适应性要求的正确表述方式,并将其纳入相关文件的建议。     

Evaluation and Trend Analysis of Surface Water Quality in Zhengzhou in 1998–2008

Abstract

Water pollution is one of the major environmental problems, especially in urban areas. Due to rapid urban expansion and industrialization, water pollution in Zhengzhou City, the capital of Henan Province in central China has become a serious problem for its development. In this study, the surface water quality was evaluated using Nemerow Comprehensive Pollution Index (NCPI), and the change trend was calculated using methods of Mann-Kendall test and Sen’s slope estimator, based on the monitoring data from 1998 to 2008. The results show that the NCPI ranged from 3 to 50 in 70% of the monitoring cases, implying that most rivers were seriously polluted. However, this serious polltuon is expected to be gradually improved, as the concentration of water pollutants and NCPI declined significantly in most rivers. Water pollution in reservoirs was much lower than rivers, and the NCPI in the three monitored reservoirs was lower than 3 in most years, and shows a downward trend. Although the surface water quality was gradually improved, great efforts are still needed to enhance the protection and improvement of surface water environment.     

Comparative experimental analysis of the effect of convective heat losses on the performance of parabolic dish water heater

This paper reveals comparative experimental analysis of the effect of variation of natural and forced convection heat losses on the performance of prototype parabolic dish water heater with coated and non-coated receivers. With the above-described system, hot water needs in domestic applications can be fulfilled instantly. A parabolic dish collector was used for instant water heating. Design of solar parabolic dish collector consists of truncated cone-shaped helical coiled receiver made up of copper at focal point. Instantaneous efficiency of 63% and 48% has been achieved with coated and non-coated receivers. This prototype has been evaluated for its performance with water flow rate of 0.0076 kg/s during the months of April and May 2010 at Shivaji University, Kolhapur, Maharashtra, India (latitude: 16.42° North, longitude: 74.13° West).     

Temporal and spatial evolution characteristics of sunshine duration over Qinghai-Tibet Plateau from 1961 to 2020北大核心CSCD

Based on observation data of daily sunshine duration from 1961 to 2020 at 175 meteorological observation stations over Qinghai-Tibet Plateau and its surrounding areas, spatial transformation analysis, climate trend analysis and M-K mutation test were used to analyze the temporal and spatial variation characteristics of the seasonal and annual sunshine duration in the region in the last 60 years. The results show that (1) annual average sunshine duration was 2 323 h, the maximum was 3 487 h in Gaer, Tibet, and the minimum was 771 h in Ya'an, Sichuan. The high-value areas were mostly located in western Tibet, northern Qinghai, western Gansu, and Xinjiang, and the low-value areas were mostly located in Nyingchi in Tibet, the mountainous area on the western edge of the Sichuan Basin, and northwestern Yunnan. The highest sunshine duration was recorded in winter (631 h), and the lowest was recorded in autumn (555 h) among the four seasons. (2) The average decrease in annual sunshine duration was 10.27 h/10 a. The largest rates of decrease were mainly in Gannan of Gansu and Ganzi of Sichuan, with the largest rate of decrease of 130 h/10 a. The areas with large rates of increase were mainly in Hotan area of Xinjiang, Liangshan of Sichuan and Lhasa of Tibet, with the largest increase of 61 h/10 a. Among the four seasons, spring exhibited an upward trend, and the remainder exhibited a downward trend. (3) Before 2017, the annual sunshine duration increased but declined after 2017. Spring sunshine duration had the largest number of mutation years, and the earliest mutation time was 1963. Winter had the fewest number of mutation years and the latest mutation time occurred in 2015. In summary, the annual and seasonal sunshine duration of Qinghai-Tibet Plateau vary greatly in space, but with the general characteristics of more sunshine in the northwest and less in the southeast, and sunshine hours were mainly decreasing, with 2017 as a mutation point of annual sunshine duration. Most areas of Qinghai-Tibet Plateau have great potential for photosynthetic production and are suitable for the development of light-loving plants and high-density planting. Shade-loving or shade-tolerant plants, including tea, are suitable for development in remote mountainous areas with low sunshine values in the western part of the basin, including Ya’an, Sichuan, and other areas, such as Medog, Tibet. © 2022 Science Press. All rights reserved.     

农产品质量安全内部协调度和耦合度测算及影响因素分析

在讨论农产品质量安全内涵的基础上,构建了农产品数量安全和质量安全指标体系,基于熵值法、CRITIC法、Ganger因果检验和回归分析等方法,使用2005—2018年中国时序数据,测度农产品质量安全的耦合度和协调度,并对农产品质量安全内部协调度的农业要素投入和管制导向影响进行了研究。研究表明：农产品质量安全内部存在相对单向的扰动,属于数量安全高于质量安全的非均衡体系;农产品质量安全内部呈现出高度的内部耦合,但发展协调度不高;化学品投入和产业投入对农产品质量安全内部协调发展具有推动作用,其他要素投入影响不明显;管制导向对农产品质量安全内部协调度有积极影响,其中,农业支持保护补贴和地理标志农产品登记数量的正向影响最大。未来应该通过优化管制效能,不断提高技术投入等要素的投入效率。     

抛光打磨车间便携式除尘器本体设计与试验

基于气旋分离和滤筒过滤的除尘原理,采用气旋分离作为一级除尘分离大颗粒粉尘,滤筒过滤作为二级除尘去除细颗粒物,设计并构建了适用于抛光打磨车间的便携式除尘器试验模型,并对其运行性能参数进行测试。结果表明：除尘器处理风量为117～179 m³/h,漏风率和设备阻力随处理风量的增加而升高,漏风率控制在3.52%以内,设备阻力最小为163 Pa,最大为393 Pa;除尘效率随风量的增大而发生轻微降低,该便携式除尘器的最高除尘效率达99.63%。     

西藏古乡沟泥石流模型试验研究

通过模型试验，研究不同类型（粘性、稀性、水石流）和不同规模（Ｐ＝２％、４％）的泥石流在古乡沟堆积扇上的运动和冲淤规律，同时进行防治工程模型试验研究，结合野外调查和资料对比，选择合理的防治工程方案，为工程设计提供可靠的依据和数据。本文结论对川藏公路与古乡沟类似灾害的整治有一定的参考价值     

典型大气环境玻璃钢天线罩聚氨酯涂层工艺老化行为研究

通过南海海洋大气环境、海南万宁湿热乡村大气环境、西藏拉萨高原大气环境户外大气暴露对玻璃钢基灭线罩聚氨酯涂层工艺进行了老化试验，运用光泽、颜色、粉化率、SEM等手段测试了涂层在户外大气暴露的性能变化和表面形貌，并进行对比分析。结果表明，在相同大气环境中，工艺玻璃钢板／雷达罩底漆／浅灰航天聚氨酯涂层耐候性能优于工艺玻璃钢板／环氧聚酰胺／弹性聚氨酯磁漆涂层的耐侯性能；对于同种工艺，西沙海洋大气环境对其耐侯性的影响最大，其次是万宁湿热乡村环境，拉萨高原环境影响较小；光照、温度、湿度是涂层老化的主要原因。     

环境工程与试验技术发展动态综述

环境适应性作为装备的质量特性之一越来越受到重视,而随着技术的进步,环境试验方法也得到了飞速的发展。本文对环境工程和试验技术的发展历程进行了回顾,并对环境试验的发展趋势进行了展望。