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61.
汉江流域土地利用/覆被变化的水文效应模拟研究   总被引:1,自引:0,他引:1  
针对流域LUCC驱动因子众多、驱动因子与土地利用/覆被变化之间存在复杂的非线性动态关系的特点,以汉江上游流域LUCC模拟为例,构建基于人工神经网络(ANN)与元胞自动机(CA)的模拟土地利用/覆被变化的CA ANN耦合模型,并应用该模型预测汉江上游流域2020s年代的LUCC变化情景。结果表明:2020s汉江黄家港站上游流域水田、旱地、灌木林与建设用地面积均有不同程度的增加,其中建设用地增幅最大,与区域交通和城市化的迅猛发展趋势相符;除建设用地增幅变化较大之外,1980s~2000s与2000s~2020s两个时期其余土地利用/覆盖类型的面积变化率都比较相近,表明CA ANN耦合模型能够刻画土地利用/覆盖类型的转换规律,在流域土地利用/覆被变化的复杂非线性动态演变情景的模拟预测方面是可行的。在此基础上,应用SWAT分布式水文模型模拟汉江上游流域水文过程。研究结果表明:在1980s年代、2000s年代及预测的2020s年代LUCC情景下,汉江上游流域年平均径流量呈增加趋势,LUCC对径流量年内影响较汛期显著,多年平均蒸散发量呈增加趋势  相似文献   
62.
通过实验与实际工程相结合,定量描述了大气采样系统中金属氧化物的存在对SO2测定值的影响,并阐述了其反应机理,提出了相应措施。  相似文献   
63.
Municipal solid waste (MSW) landfills are one of the major sources of offensive odors potentially creating annoyance in adjacent communities. At the end of May 2007, an odor pollution incident occurred at the Tianziling landfill site, Hangzhou, China, where the residents lodged complaints about the intense odor from the landfill, which drew a significant attention from the government. In this study, ambient air monitoring was conducted at the Tianziling landfill site. The main odor composition of the gas samples collected on June 1st 2007 and the reduction of various odorous gases from the samples collected on June 1st 2009 due to the applied odor control techniques were determined using gas chromatography-mass spectrometry (GC-MS). In addition, variations of primary odorous gaseous (NH3 and H2S) concentrations at different locations in the landfill site from July 2007 to June 2009 were also investigated by using classical spectrophotometric methods. Results showed that a total of 68 volatile compounds were identified among which H2S (56.58-579.84 μg/m3) and NH3 (520-4460 μg/m3) were the notable odor components contributing to 4.47-10.92% and 83.91-93.94% of total concentrations, respectively. Similar spatial and temporal shifts of H2S and NH3 concentrations were observed and were significantly affected by environmental factors including temperature, air pressure and wind direction. Odor pollution was worse when high temperature, high humidity, low air pressure, and southeast, northeast or east wind appeared. Moreover, the environmental sampling points of the dumping area and the leachate treatment plant were found to be the main odor sources at the Tianziling landfill site. The odor control technologies used in this project had a good mitigating effect on the primary odorous compounds. This study provides long-term valuable information concerning the characteristics and control of odors at landfill sites in a long run.  相似文献   
64.
利用红外技术探测地质构造是预防巷道作业重大安全事故的有效途径。笔者根据红外辐射原理 ,分析了地质构造引起的岩石密度变化和巷道围岩辐射功率之间的相关性 ,提出了红外探测巷道地质构造的理论、方法及适用条件。应用结果表明 :红外探测技术不仅可简便、直观地分析和预测采掘巷道围岩地质的变化趋势 ,而且可用于巷道围岩瓦斯涌出异常地段的原因探测 ,指导安全防范措施的有效实施  相似文献   
65.
为了实现废弃棉织物的高效资源化利用,采用浓磷酸预处理,将棉纤维转化为葡萄糖,并回收高纯度涤纶.以磷酸浓度、磷酸与原料液固比、预处理温度和时间为研究对象,以涤纶回收纯度、葡萄糖收率为考察指标,采用中心组合设计(CCD),建立响应面模型对预处理工艺参数进行优化.并确定了最佳的浓磷酸预处理工艺条件为:磷酸质量分数85%,液固比15:1,预处理时间7 h,预处理温度50℃.在此条件下涤纶回收纯度可达100%,葡萄糖收率可达79.0%,且实验验证值与模型预测值较为接近,模型精度较高.此外,再生纤维素不经干燥直接酶水解,葡萄糖收率可被进一步提高至83.0%.  相似文献   
66.
Agricultural practices affect the production and emission of carbon dioxide (CO2) from paddy soils. It is crucial to understand the effects of tillage and N fertilization on soil CO2 flux and its influencing factors for a better comprehension of carbon dynamics in subtropical paddy ecosystems. A 2-yr field study was conducted to assess the effects of tillage (conventional tillage [CT] and no-tillage [NT]) and N fertilization (0 and 210 kg N ha?1) on soil CO2 fluxes during the 2008 and 2009 rice growing seasons in central China. Treatments were established following a split-plot design of a randomized complete block with tillage practices as the main plot and N fertilizer level as the split-plot treatment. The soil CO2 fluxes were measured 24 times in 2008 and 17 times in 2009. N fertilization did not affect soil CO2 emissions while tillage affected soil CO2 emissions, where NT had similar soil CO2 emissions to CT in 2008, but in 2009, NT significantly increased soil CO2 emissions. Cumulative CO2 emissions were 2079–2245 kg CO2–C ha?1 from NT treatments, and 2084–2141 kg CO2–C ha?1 from CT treatments in 2008, and were 1257–1401 kg CO2–C ha?1 from NT treatments, and 1003–1034 kg CO2–C ha?1 from CT treatments in 2009, respectively. Cumulative CO2 emissions were significantly related to aboveground biomass and soil organic C. Before drainage of paddy fields, soil CO2 fluxes were significantly related to soil temperature with correlation coefficients (R) of 0.67–0.87 in 2008 and 0.69–0.85 in 2009; moreover, the Q10 values ranged from 1.28 to 1.55 and from 2.10 to 5.21 in 2009, respectively. Our results suggested that NT rice production system appeared to be ineffective in decreasing carbon emission, which suggested that CO2 emissions from integrated rice-based system should be taken into account to assess effects of tillage.  相似文献   
67.
以工业硫酸氧钛为原料水解制得SO42-/TiO2光催化剂,并以苯酚为目标降解物,考察了SO24-/TiO2的光催化性能。结果表明:随着SO42-/TiO2制备过程中焙烧温度的升高,其光催化活性逐渐增加,650℃焙烧获得的SO24-/TiO2的光催化活性最好,此后再升高温度会因催化剂中硫的挥发而下降;在确定苯酚原液初始浓度为50 mg/L条件下,SO42-/TiO2的光催化降解苯酚的最佳工艺条件为反应时间2 h、苯酚pH为7、催化剂用量1 g/L。XRD、SEM和FTIR的分析结果显示实验温度下制得的SO42-/TiO2均为锐钛型TiO2;其间掺杂的SO24-在TiO2表面分散性较好,没有聚集成大的颗粒;红外分析的结果初步判定低温(<550℃)焙烧制得的催化剂SO42-在TiO2表面是螯合双配位吸附,高温焙烧时(>550℃)SO42-在TiO2表面是桥式配位吸附。  相似文献   
68.
Endosulfan in China 1—gridded usage inventories   总被引:9,自引:0,他引:9  
Background, aim, and scope  Endosulfan, an organochlorine pesticide (OCP), is genotoxic in mammalian cells and generally considered to be toxic and classified by the World Health Organization and the US Environmental Protection Agency as priority pollutants and a nominator for inclusion in a future iteration of the persistent organic pollutants treaty. Endosulfan is a currently used pesticide and still being used worldwide. The general trend of total global endosulfan use has increased continuously since the first year when this pesticide was applied. It is critical to create national endosulfan usage/emission inventories for China to carry out source–receptor relation analysis, risk assessment, and other research related to endosulfan in this country. Chinese inventories have been published for some OCPs, such as technical HCH and lindane, DDT, and chlordane; for endosulfan, however, there has not been any usage inventory available on any scales (national or provincial), although endosulfan has been widely used since 1994 in this country. This is the first part of the work. The goal of this paper is to quantify the historical production and usage of endosulfan in China and to compile gridded historical usage inventories of endosulfan for this country. Based on these usage inventories, emission and residue inventories will be created, which is the goal of the second part of the work. Materials and methods  Due to the lack of national production and usage information of endosulfan in China, a method to estimate the use of endosulfan was developed. First, information of crops on which endosulfan is applied and average endosulfan use and annual application frequencies of endosulfan on these crops were collected. Secondly, usage of endosulfan on each crop was estimated using the national cropland area for each province from Chinese government reports. Finally, with the help of GIS (geographic information system), the usage data of this insecticide was allocated to a grid system, with a 1/4° longitude by 1/6° latitude resolution, with a size for each grid cell of approximately 25 km by 25 km. Results and discussion  The use of endosulfan in agriculture in China started on cotton in 1994, and on wheat, tea, tobacco, apples, and other fruits in 1998. Endosulfan usage on cotton, wheat, tea, tobacco, and apples in China has been estimated to be approximately 25,700 t between 1994 and 2004. The province with the highest usage of endosulfan is Henan Province, with a total usage reaching 4,000 t, followed by the uses in Xinjiang Autonomous Region (3,200 t), Shandong Province (3,000 t), Hebei Province (2,100 t), and Anhui Province (1,900 t). Gridded usage inventories of endosulfan at a 1/4° longitude by 1/6° latitude resolution have been created, which indicate that the intensive endosulfan use was in the south of Hebei Province, west of Shandong Province, east of Henan Province, north of Anhui Province, east of Jiangsu Province, and some areas in Yunnan Province and Xinjiang Autonomous Region. General agreement has been found between the usage data from our estimation and the small amount of usage data published in China. Conclusions  This is the first national gridded endosulfan usage inventory produced for China. The annual applications of endosulfan from 1994 to 2004 in China were estimated based on the total areas of major crops, on which endosulfan was applied, and spatial distribution of the application was generated at provincial and prefecture levels. With the help of GIS, endosulfan usage based on prefecture was transferred to a 1/4° longitude by 1/6° latitude gridding system. The satisfaction of the inventories was supported by the consistence between the estimation of the annual usage and the reported annual production of endosulfan. Recommendations and perspectives  This gridded endosulfan usage inventory created in this study will be improved upon availability of new information of endosulfan. The usage inventories can be used to create gridded emission and residue inventories for this insecticide. It is believed that this work will pave the way for further endosulfan studies in China and beyond.  相似文献   
69.
针对增塑剂邻苯二甲酸二丁酯,邻苯二甲二辛酯的生产及废水治理现状,对生产过程的清洁生产审计及是提出清洁生产方案,并进行了实施,实施效果显著,污染物总量减少了85%产品生产所需原材料有所下降,不仅具有环保效益,同时也有一定的经济效益。  相似文献   
70.
此文分析了产品成形的特点,模具承载的负荷特点,从而在成形工艺上、润滑上、模具结构及选材上采取了相应的措施.用H-4水基高分子润滑剂和3Cr2W8V制作冷挤压模都取得了明显效果.  相似文献   
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