接处警系统的可靠性研究

接处警的可靠性是应急系统正确、迅速、有效地处理应急事件,减少事故损失的关键,直接关系到人民的生命财产安全,也关系到社会的稳定.接处警系统是由接警、处警和事故后处理3部分构成的串联系统,任何部分的失误都会导致应急事故处理的失误.以接处警单元可靠性框图为基础,分析了接处警的隐性失误和显性失误,构建了单一、并联和表决逻辑的接处警可靠度及失误率的计算模型.对取自常州的实例进行了整理,获取了接处警的隐性失误和显性失误数值并代入接处警模型,认为3选2表决逻辑的接处警结构可以降低隐性失误率和显性失误率,并据此提出了提高应急系统接处警可靠性的具体措施.     

A combined plasma photolysis (CPP) method for removal of CS2 from gas streams at atmospheric pressure

A combined plasma photolysis (CPP) reactor that utilizes a dielectric barrier discharge (DBD) plasma and 207 nm UV radiation from discharge-driven KrBr^* excimers was designed and constructed. Gas streams containing CS₂ were treated with stand-alone DBD and CPP at atmospheric pressure. In comparison to DBD, CPP greatly enhanced the removal efficiency at the same applied voltage, waste gas concentration and gas residence time. Thus the applied voltage could be reduced to a certain extent in the plasma processing of industrial wastes. Influences of the KrBr^* radiation, inlet CS₂ concentration and gas residence time on CS₂ removal by CPP were also studied. In addition, the likely reaction mechanisms for the removal of CS₂ by CPP are suggested based on the byproducts analysis. The enhanced removal efficiency and reaction mechanisms implied that the CPP process would probably be suitable for the removal of a large number of gaseous pollutants.     

Simultaneous quantification of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and pharmaceuticals and personal care products (PPCPs) in Mississippi river water, in New Orleans, Louisiana, USA

An effective analytical method for simultaneously determining 16 polycyclic aromatic hydrocarbons (PAHs), 28 polychlorinated biphenyl (PCBs), and 12 pharmaceuticals and personal care products (PPCPs) has been developed to measure their concentrations in the Mississippi river waters in New Orleans, Louisiana, USA. The method involves the simultaneous extraction of the selected PAHs, PCBs, and PPCPs, from the aqueous phase by solid phase extraction using two-layer disks consisting of C(18) and SDB-XC, and collection of suspended solid in water samples by 0.2-0.6 microm filter in a single step. Target compounds adsorbed on the extraction disks were eluted with methanol, acetone, and dichloromethane. The suspended particles retained by the filter were sonically extracted using the same solvents. GC/MS was used for quantification of PAHs and PCBs directly and of PPCPs after derivatization. The analytical method was used in a 6-month field study of the Mississippi river water for contamination by PAHs, PCBs, and PPCPs and the following concentrations (ng/l) have been obtained: clofibric acid (3.2-26.7), ibuprofen (0-34.0), acetaminophen (24.7-65.2), caffeine (0-38.0), naproxen (0-135.2), triclosan (8.8-26.3), bisphenol A (0-147.2), carbamazepine (42.9-113.7), estrone (0-4.7), 17beta-estradiol (0-4.5), total PAHs (62.9-144.7), and total PCBs (22.2-163.4).     

Biodegradation of nonylphenol polyethoxylates under Fe(III)-reducing conditions

Biodegradation behavior of nonylphenol polyethoxylates (NPEOs) under Fe(III)-reducing conditions was investigated. The study demonstrated that NPEOs could be rapidly biodegraded under Fe(III)-reducing conditions. Almost 60% of the total NPEOs were removed within three days and the maximum biodegradation rate was 34.95+/-0.84 microM d(-1). NPEOs were degraded via sequential removal of ether units under Fe(III)-reducing conditions. No nonylphenol polyethoxy-carboxylates (NPECs) were formed in this process. This ether removal process was coupled to Fe(III) reduction. Nonylphenol (NP), nonylphenol monoethoxylate (NP1EO), and nonylphenol diethoxylate (NP2EO) slightly accumulated in the anaerobic biodegradation process. The accumulation of these estrogenic metabolites led to a significant increase in the estrogenic activity during the biodegradation period. The calculated estrogenic activity reached its top on day 14 when the total concentration of these estrogenic metabolites was maximal. This is the first report of the primary biodegradation behavior of NPEOs under Fe(III)-reducing conditions. These findings are of major environmental importance in terms of the environmental behavior of NPEO contaminants in natural environment.     

粮食生产的投入产出影响因素分析--基于江苏省粮食生产的实证研究

在对江苏省13个市的粮食生产数据搜集整理的基础上,运用面板数据模型进行了投入产出的影响因素分析。结果显示,土地是影响目前江苏省粮食生产的最主要因素,因此随着城市化进程的不断加快,耕地面积的缩减,粮食产量有下降的趋势;此外,由于技术效率和劳动生产率的提高,出现了在劳动力投入不断下降条件下的粮食产量上升,但是二者表面上的反向关系不应当被简单理解为劳动力对产出弹性的负作用;在农资投入方面,化肥与农业机械动力的投入对于江苏省粮食生产有积极影响。     

公共建筑火灾风险评价方法研究

建筑物的火灾危险度包括火灾对建筑物本身的破坏以及对建筑物内部人员伤害两个方面.本文在古斯塔夫火灾危险度法和层次分析法的基础上,采用模糊数学中的一些方法对火灾危险源进行处理.将火灾风险定义若干因子,每个因子对应火灾危险源的不同特性.通过评价得出建筑物所属的安全等级以及一定区域内建筑火灾风险的排序.在评价过程中考虑控制风险的力量,特别是消防队控制风险的力量对建筑物火灾风险的影响,使评估结果更加合理准确.该方法可以使消防部队快捷迅速的了解辖区内重要公共建筑的安全情况,以及如何合理的布置消防站点,降低城市区域风险.     

光生物反应器内CO2传输与微藻固碳性能强化

CO₂气体可为微藻光合作用提供必需的碳源,CO₂在藻液中的混合、溶解及传输特性显著影响了微藻的生长固碳.在微藻光生物反应器中,气泡在藻液中的生长、脱离、聚并、上升等动力学行为主要由气体分布器决定.本文以气体分布器为研究对象,研究在不同孔径及孔间距下对15%（V/V）CO₂气体在悬浮液中的气泡行为、CO₂溶解与混合特性以及对微藻生长固碳的影响.结果表明：气泡上升速度随气体分布器孔径及孔间距的减小而减小,导致CO₂气泡在藻液中停留时间增加,强化了CO₂溶解传输,CO₂体积传质系数提高了143%,混合时间降低了24%,最终使微藻生物质浓度提高18.8%,固碳速率提高23.2%.     

西安高新区多情景碳达峰预测及减排路径分析

第十三届全国人民代表大会第五次会议提出要致力于推进碳达峰碳中和工作,促进经济社会向全面绿色低碳转型,实现高质量发展.西安高新区作为陕西省重要的科技创新和产业聚集区,经济发展在很大程度上依赖于能源消耗,碳减排的任务就显得尤为艰巨.以西安高新区为研究对象,首先通过系统核算园区内碳排放,对不同能源种类和不同行业企业碳排放现状进行分析;然后利用Kaya模型设定多种独立的碳达峰情景,预测不同情景下的碳排放总量值及碳达峰时间;最后结合西安高新区发展特点科学甄选相应的碳减排路径,给出合理的减排建议.结果表明,目前电力消耗碳排放占比最多且份额呈逐年上升趋势,工业碳排量始终占主导地位且第三产业发展日益蓬勃;碳排放因子情景、能源强度情景和经济水平情景这3种情景下可于2030年达到碳达峰,其中经济发展水平对西安高新区未来碳达峰的峰值和时间影响最大,产业结构情景、能源结构情景和人口规模情景在2030年前没有出现峰值;未来减排路径主要从电力部门脱碳、经济稳健高质量发展、能源及产业结构绿色升级和构建绿色交通体系入手,可为实现碳中和预留更多的准备时间,也为我国工业园区低碳发展提供决策参考.     

我国地下水硝酸盐污染及源解析研究进展

我国地下水中硝酸盐污染问题严峻,尤其农业产区地下水硝酸盐污染日益突出,严重影响了地下饮用水安全,急需引起重视.通过综述发现,我国地下水中硝酸盐的主要来源为大气沉降、土壤氮、农业施肥和粪便污水等,其中粪便污水和农业施肥是地下水硝酸盐超标的主要原因.总结了水化学分析法、多元统计分析法、稳定同位素示踪法和微生物源追踪等技术在地下水硝酸盐溯源中的应用.各种溯源方法均有一定的局限性,建议采用多种方法联合识别地下水中硝酸盐来源,并通过多元统计分析和同位素定量解析模型计算不同污染来源贡献率.硝酸盐污染溯源经历了从定性到定量的研究过程,目前基于δ¹⁵N-NO₃ ^-和δ¹⁸O-NO₃ ^-解析硝酸盐来源的SIAR和MixSIAR模型已经相当成熟,但由于不同输入端元同位素特征值范围相互重叠,不同时空变化等条件下δ¹⁵N-NO₃ ^-和δ¹⁸O-NO₃ ^-值具有一定差异,以及氮迁移转化过程中的同位素分馏等的影响,导致模型计算得出的结果还存在不确定性,需要进一步优化模型的解析方法,以更精准地获取硝酸盐污染来源及其贡献率,服务于地下水资源的科学管理.