用于结构振动控制的电流变阻尼器的设计

地震是一种随机振动 ,一旦发生将影响结构的安全。ER智能材料是一种可控流体 ,它在电场作用下可从牛顿流体变为剪切屈服应力较高的粘塑性体 ,且这种转变连续、可逆、迅速 ,因此 ,可用它来制作可调阻尼器 ,实现对工程结构地震反应的半主动控制。本文在简要介绍了ER电流材料的基本性能和ER可调阻尼器的工作原理的基础上设计了一个具有较大可调范围和较高阻尼力的ER电流变阻尼器     

覆膜滤料对特殊烟尘处理的优越性

覆膜滤料是新型的过滤材料 ,弥补了普通滤料在烟尘处理过程中的不足。特别是对含油雾、粘结性强的粉尘以及高湿等特殊烟尘治理具有良好的效果     

基于河道生态基流保障的农业生态补偿量研究

针对西北干旱和半干旱地区流域非汛期农业需水和生态基流间的矛盾问题,论文提出了基于河道生态基流保障的农业生态补偿量计算方法。从生态基流得到保障后农业灌溉用水受到影响的角度出发,通过引入作物需水系数建立河道生态基流保障造成的农业用水短缺量与产量损失间的关系,定量计算农业生态补偿量。以宝鸡峡灌区为实例,计算了河道生态基流保障的农业生态补偿量,确定宝鸡峡灌区不同情形下的补偿上、下限,分别为5.25 亿元和0.37 亿元。生态补偿对象为宝鸡峡灌区因河道生态基流保障导致产量受损的农户,补偿的主体为流域的相关管理部门,生态补偿标准的实施也不应只局限于现金发放,也可以用投资建设等形式进行补偿,以提高宝鸡峡灌区的农业可持续发展。     

黑碳研究进展

黑碳由生物质和化石燃料不完全燃烧所产生的具有高度热稳定性的含碳物质,广泛存在于土壤、沉积物、大气乃至极地和高山的冰雪中。工业革命以来,人类活动促使大量的黑碳进入到环境中,导致全球黑碳的背景值显著升高。土壤和沉积物中的黑碳有着长时间尺度(约10000yr)的降解周期,在全球碳循环过程中起着部分"汇"的作用。大气和冰雪中的黑碳通过"辐射强迫"作用吸收太阳辐射,促进全球变暖进而影响全球气候变化。目前主要有光学(optical)、热氧化(TO)、化学氧化(CTO)等方法用于黑碳的分离和测试。大气中的黑碳研究一般采用光学法,而土壤和沉积物中的黑碳研究则主要采用化学氧化法。本文全面总结了黑碳在环境中的研究进展,并指出黑碳对全球变暖的贡献是今后黑碳的重要研究方向。     

CEMS检测平台流场效应研究与工程设计

本研究项目设计了小型立式环型风洞系统和流场模拟两套实验装置。用工程流体力学实验的方法，对系统内气体压力、流量变化的调节控制方法、通风机的能量消耗，以及在检测平台系统工作段形成均匀流动流场的设计方法等工程实际问题，进行了一系列的试验研究。在试验研究的基础上确定了检测平台系统的设计方案。     

Changes in peak flow with decreased forestry practices: analysis using watershed runoff data

The prevalence of forestry practices such as thinning and pruning have gradually decreased since the 1980s. Researchers have noted an increased flood risk with decreased forestry practices for coniferous plantations in Japan on the basis of infiltration and overland flow measurements at a plot scale (typically several square meters). However, no studies have examined changes in peak flow with decreased forestry practices at a watershed scale (typically several tens or hundreds of square kilometers) even though flood disasters generally occur at this scale in Japan. We examined changes in frequency distributions of daily precipitation (P) and runoff (Q) during the period 1979-2007 at the Terauchi watershed, where forestry practices are known to have decreased. For this purpose, we divided P and Q data into 14 and 15 classes according to the magnitude, respectively, and examined changes in the frequency for each class during the period. We observed no significant increasing trend for any P or Q class. Even when taking into account the effect of interannual variations in precipitation on the frequency for each Q class, there was no significant increasing trend in the frequencies except for two Q classes with moderate Q values. These results suggest that the increase in flood risk due to decreased forestry practices might be less than expected.     

A Multi-Channel Continuous Water Toxicity Monitoring System: Its Evaluation and Application to Water Discharged from a Power Plant

A multi-channel continuous water toxicity monitoring system was, after confirming the systems' performance, implemented to samples of water discharged from power plants to detect and classify their toxicity using several recombinant bioluminescent bacteria. Each channel of the system is composed of a series of two mini-bioreactors to enable a continuous operation, i.e., without system interruption due to highly toxic samples. A different recombinant bacterial strain was present in each channel: DPD2540 (fabA::lux CDABE), DPD2794 (recA::luxCDABE), and TV1061 (grpE::luxCDABE), which are induced by cell membrane-, DNA-, and protein-damaging agents, respectively. GC2 (lac::luxCDABE) is a constitutive strain, whose bioluminescence is reduced by an increase in cellular toxicity. Phenol and mitomycin C (MMC) were used for evaluating the system's performance to detect toxic chemicals. These samples were injected into the second mini-bioreactor according to a step or bell-curve manner. The field samples used in this study were obtained from the water discharged from two different power plants in Korea – from a nuclear power plant and a thermo-electronic power plant, and were injected into the second mini-bioreactor to initiate the toxicity test. Each channel showed specific bioluminescent (BL) response profiles due to the toxic compounds present in the water samples. Comparing the BL signals between the standard toxic chemical samples and discharged water samples, the equivalent toxicity of the field water could be estimated. Finally, it was proved that this novel continuous toxicity monitoring system can be used as an alternative tool for the quick monitoring and control of water quality, as well as aid in the setting up of a new monitoring strategy to protect the source of tap water and in the prevention of polluted water discharge.     

流动注射在线富集原子吸收法测定痕量铅镉

在含铅、镉的试液中加入pH=5.72乙酸-乙酸钠缓冲溶液3.20 mL,泵的转速恒为5 mL/min,用自制的强酸性阳离子交换树脂柱对试液中的铅、镉在线富集150 s,1.50 mol/L HNO3溶液洗脱20 s,火焰原子吸收法测定铅、镉的含量。该方法的线性范围分别是0~80.0μg/L、0~40.0μg/L,检出限分别为3.0μg/L、1.0μg/L,富集倍数分别为40倍、35倍。用该方法测定地表水中铅、镉的含量,结果满意。     

农业生态系统能流分析中几个问题的探讨

本文就目前广泛应用的农业生态系统能流分析方法及有关概念作了分析，提出了辅助能替代率的概念。建议用辅助能替代率代替能量产投比对农业生态系统进行能流分析。文中还讨论了工业辅助能的计算及其在不同系统间或同一系统不同时段的可比性。     

基于物质点法和极限平衡法公路沿线弃渣场危险性评价

公路沿线弃渣场的失稳破坏,不仅容易造成其下方道路和河流的堵塞,而且严重威胁人民的生命和财产安全.快速、准确和批量地评价公路沿线弃渣场危险性就显得十分必要.通过对公路沿线弃渣场进行遥感图像识别、无人机拍摄、现场调查及试验,确定了6个弃渣场危险性影响因子,运用物质点法对实体弃渣场进行了多因素多水平的数值模拟,得出各因子对弃...