东海区带鱼伏季休渔效果及其资源的合理利用

根据2002-2003年东海区带鱼年龄鉴定资料,并引用以往的带鱼渔业生物学研究结果,作为估算带鱼死亡系数和建立动态综合模型所需的有关参数值估算的依据,从而运用Ricker动态综合模型分析了在现行渔业条件下东海区带鱼伏季休渔效果和带鱼资源利用状况以及变更渔业利用情况对带鱼渔业所产生的影响。结果表明:在现行渔业下(tc=0.5a,F=2.61/a),东海区实施3个月的伏季休渔制度能使年平均资源量增加87%,年产量增加29%,渔获平均体重增加42%;带鱼资源的利用虽处于捕捞过度状态之中,但尚能承受较大的捕捞压力,资源结构利用不合理之处是捕捞大量的幼鱼群体,渔获个体依然过小,渔获平均体重仅为75g/ind.;单位补充量渔获量(Y/R)随tc变化的影响大于随F的变化,建议在维持现有伏季休渔制度下,应逐渐降低捕捞强度,并以提高起捕规格放大网目尺寸作为今后一个时期首选的渔业管理目标,应是较为现实的资源合理利用措施。     

封闭湖泊蓝藻水华预警机制及应急控制方法

随着我国城市化进程的不断推进以及经济的快速发展,城市封闭湖泊水体污染日益严重,蓝藻水华现象频频发生。文章分析了该类水体水华的主要影响因素,并提出了预警机制。根据已开展的湖泊污染治理工程效果,针对性地提出了几种有效的封闭湖泊蓝藻水华应急控制方法。     

鄂南4种典型土地利用方式红壤CO2排放及其影响因素

以湖北省咸宁地区分布的红壤为研究对象,采用静态箱法对4种典型土地利用方式（水稻-油菜轮作田,旱地,林地,果园）土壤CO₂的排放特征及其相关影响因子进行了观测研究.结果表明,4种利用方式土壤CO₂的年排放总量从高到低分别为水稻-油菜轮作田1 129 g/(m²·a),果园828 g/(m²·a),旱地632 g/(m²·a),林地533 g/(m²·a).土壤CO₂排放通量呈现明显的季节性变异,水田夏季淹水期排放低,而其它3种土壤都是夏季最高,春秋次之,冬季最低,并与对应的大气温度、土壤温度变化趋势基本一致.其中5 cm地温与4种土壤CO₂排放通量均成极显著的相关关系,且以林地的相关性最大.除水田外,其它土壤CO₂排放通量与大气温度均呈显著正相关关系.根据5 cm地温与CO₂排放通量的相关方程计算得出,4种利用方式红壤的Q₁₀分别为水田1.51,果园1.88,林地2.08,旱地2.7.土壤CO₂排放通量与土壤WFPS之间并没有明显的相关关系.土壤可溶性有机碳（DOC）含量与CO₂排放通量的变化趋势基本一致,且DOC在降水或淹水的情况下显著增大.     

呼吸效应对矿井封闭火区氧浓度的影响分析

为避免因火区封闭导致重大安全事故发生,通过采集某矿井1 d内3个不同监测点的大气压力变化情况,建立大气压力波动模型并分析计算,同时建立火区内外压差100,750 Pa情形下的氧浓度模型进而获得火区内侧氧气浓度因呼吸效应,在不同压差、体积大小火区、风阻、瓦斯涌出量、封闭时刻等多因素耦合影响下随时间的变化规律,以评估火区危险性。研究结果表明:井下大气随地面大气周期波动,封闭火区内、外侧之间的气压差因外界大气波动呈现16 h的余弦波动和8 h的线性波动周期变化;密闭质量好的火区具有更好地抗干扰性,内侧氧浓度的降低主要依靠瓦斯稀释;密闭质量差的火区,内侧氧浓度易受到火区涌出瓦斯、外界涌入大气双重影响;火区氧浓度在2%~12%之间波动,以至火区存在发生瓦斯爆炸的可能性;火区内外压差较大时,氧浓度波动变化幅度更大,危险作用持续时间更长。结合火区氧浓度波动模型,可有效地对矿井火区采取安全的防范措施,避免瓦斯爆炸事故发生。     

Aerobic degradation of methyl tert-butyl ether by a Proteobacteria strain in a closed culture system

The contamination of methyl ten-butyl ether （MTBE） in underground waters has become a widely concerned problem all over the world. In this study, a novel dosed culture system with oxygen supplied by H2O2 was introduced for MTBE aerobic biodegradation. After 7 d, almost all MTBE was degraded by a pure culture, a member of β-Proteobacteria named as PMI, in a closed system with oxygen supply, while only 40% MTBE was degraded in one without oxygen supply. Dissolved oxygen （DO） levels of the broth in closed systems respectively with and without H2O2 were about 5-6 and 4 mg/L. Higher DO may improve the activity of monooxygemase, which is the key enzyme of metabolic pathway from MTBE to tert-butyl alcohol and finally to CO2, and may result in the increase of the degrading activity of PM1 cell. The purge and trap GC-MS result of the broth in closed systems showed that tea-butyl alcohol, isopronol and acetone were the main intermediate products.     

Distribution characteristics of dissolved organic carbon in annular wetland soil-water solutions through soil profiles in the Sanjiang Plain, Northeast China

Overwhelming evidence reveals that concentrations of dissolved organic carbon （DOC） have increased in streams which brings negative environmental impacts. DOC in stream flow is mainly originated from soil-water solutions of watershed. Wetlands prove to be the most sensitive areas as an important DOC reserve between terrestrial and fluvial biogeosystems. This reported study was focused on the distribution characteristics and the controlling factors of DOC in soil-water solutions of annular wetland, i.e., a dishing wetland and a forest wetland together, in the Sanjiang Plain, Northeast China. The results indicate that DOC concentrations in soilwater solutions decreased and then increased with increasing soil depth in the annular wetland. In the upper soil layers of 0-10 cm and 10-20 cm, DOC concentrations in soil-water solutions linearly increased from edge to center of the annular wetland （R^2 = 0.3122 and R^2 = 0.443）. The distribution variations were intimately linked to DOC production and utilization and DOC transport processes in annular wetland soil-water solutions. The concentrations of total organic carbon （TOC）, total carbon （TC） and Fe（II）, DOC mobility and continuous vertical and lateral flow affectext the distribution variations of DOC in soil-water solutions. The correlation coefficients between DOC concentrations and TOC, TC and Fe（II） were 0.974, 0.813 and 0.753 respectively. These distribution characteristics suggested a systematic response of the distribution variations of DOC in annular wetland soil-water solutions to the geometry of closed depressions on a scale of small catchments. However, the DOC in soil pore water of the annular wetland may be the potential source of DOC to stream flow on watershed scale. These observations also implied the fragmentation of wetland landscape could bring the spatial-temporal variations of DOC distribution and exports, which would bring negative environmental impacts in watersheds of the Sanjiang Plain.     

基于AHP的密闭环境空气质量评价模型及其应用

针对指数法在评价密闭环境空气质量中存在评价因素单一,不能反映多种污染物对空气环境质量的综合影响等缺点,结合模糊数学的原理与方法,对密闭环境空气质量进行评价。采用层次分析法赋权,按最大隶属原则,通过模糊数学模型对某密闭环境空气质量进行综合评价,评价结果较科学地反映了空气质量的真实状况。     

1000 MW燃煤机组电除尘深度节能技术研究及应用

电除尘设备在减少工业粉尘排放量、降低大气环境污染、保护生态环境等方面有着重要的作用,随着我国对节能减排工作的重视及环保要求的提高,保证其安全、稳定、经济、节能运行成为火电厂环保工作重点。对北仓电厂三期2×1000 MW机组电除尘电场供电方式优化、电除尘振打方式优化、电除尘闭环控制技术、电除尘高频电源技术、电除尘灰斗、瓷套蒸汽加热技术组合集成应用进行了研究,在确保除尘效率达到要求的情况下,降低运行电耗。相关的电除尘深度节能技术成果在国内同类型设备中具有一定的借鉴意义。     

砂尘试验箱原理分析改进及相关标准探讨

结合砂尘的产生和运动机理,对砂尘试验箱的设计原理和应用特点进行了说明,着重对吹砂程中空气的温度和湿度、砂尘颗粒直径比例进行了分析,对气固两相流中颗粒浓度的均匀性进行了探讨。基于砂尘的运动特性,国内应用较普遍采用的闭式循环吹砂试验设备,无法实现砂的有效分离,导致吹砂试验箱试验过程中颗粒直径比例不满足GJB 150.12A要求。在MIL-STD-810H中,已经取消了对吹砂试验相对湿度≤30%的要求。基于吹尘和吹砂引起的不同环境效应,结合吹尘和吹砂试验设备原理和国内已有设备的现状,对现有试验方法和校准规范的完善、砂尘试验箱的改进设计提出了建议和意见。同时文中也介绍了国外开式、闭式循环、可变循环等几种不同类型的砂尘试验箱作为参考,基于砂尘试验的破坏机理提出了砂尘试验箱的分类和选型建议。     

Flash point prediction for the binary mixture of phosphatic solvents and n-dodecane from UNIFAC group contribution model

The flash point temperature of Tri-n-butyl phosphate(TBP) and Tri-iso-amyl phosphate(TiAP) in n-dodecane binary mixture has been measured for the entire concentration range using the continuously closed cup flash point apparatus based on the ASTM D6450 method. The flash point was predicted using the UNIFAC group contribution model. The measured flash point was also compared with the prediction from the NRTL, UNIQUAC and Ideal solution models. The UNIFAC model is able to predict the flash point fairly well for the TBP–dodecane mixture and for TiAP–dodecane mixture no improvements is obtained over the ideal solution assumption. The flash point shows positive deviation from ideal solution behavior for both the binary mixture.