离心式机械振动台基本参数设计计算方法的探讨

该文叙述了离心式机械振动台的工作原理,提出了计算思路和方法;推导了其计算公式;并根据工程的实际情况,把复杂的计算公式,简化成代数运算式。     

Theoretical insights into the degradation mechanisms, kinetics and eco-toxicity of oxcarbazepine initiated by OH radicals in aqueous environments

As an anticonvulsant, oxcarbazepine (OXC) has attracted considerable attention for its potential threat to aquatic organisms. Density functional theory has been used to study the mechanisms and kinetics of OXC degradation initiated by OH radicals in aqueous environment. A total of fourteen OH-addition pathways were investigated, and the addition to the C8 position of the right benzene ring was the most vulnerable pathway, resulting in the intermediate IM8. The H-abstraction reactions initiated by OH radicals were also explored, where the extraction site of the methylene group (C14) on the seven-member carbon heterocyclic ring was found to be the optimal path. The calculations show that the total rate constant of OXC with OH radicals is 9.47 × 10⁹ (mol/L)⁻¹sec⁻¹, and the half-life time is 7.32 s at 298 K with the [·OH] of 10⁻¹¹ mol/L. Moreover, the branch ratio values revealed that OH-addition (89.58%) shows more advantageous than H-abstraction (10.42%). To further understand the potential eco-toxicity of OXC and its transformation products to aquatic organisms, acute toxicity and chronic toxicity were evaluated using ECOSAR software. The toxicity assessment revealed that most degradation products such as OXC-2OH, OXC-4OH, OXC-1O-1OOH, and OXC-1OH' are innoxious to fish and daphnia. Conversely, green algae are more sensitive to these compounds. This study can provide an extensive investigation into the degradation of OXC by OH radicals and enrich the understanding of the aquatic oxidation processes of pharmaceuticals and personal care products (PPCPs).     

分洪区洪灾保险工作初探

本文从洪水过程的随机特点及防洪工作的实际需要等各个方面出发,阐述了在分洪区实行洪灾保险的必要性,结合国内外已有的实践经验,分析了这一工作得以顺利开展的可能性。并在此基础上,提出了二种洪灾保险费用计算方法,实例计算结果表明,这些方法是基本可行的。     

旋流式脱水器分离最小水滴理论计算

介绍了旋流式的构造和工作原理,分析了影响性能的因素。通过对脱水器构造的剖析,找出叶片形状影响脱水效果的关键所在,从理论分析入手,推导出旋流式脱水器分离最小直径水滴的计算方法,并根据工程实践进行了检验。工程实践表明,实际应用效果与理论计算相符合。     

污水生化处理耗氧量计算与应用

根据各类型好氧工艺运行的特点,结合多年设计经验,给出详细计算公式和参数选择范围,说明每个参数含义。     

Development of a model to simulate soil heavy metals lateral migration quantity based on SWAT in Huanjiang watershed, China

Lateral transportation of soil heavy metals in rainfall events could significantly increase the scope of pollution. Therefore, it is necessary to develop a model with high accuracy to simulate the migration quantity of heavy metals. A model for heavy metal migration simulation was developed based on the SWAT(Soil and Water Assessment Tool) model. This model took into consideration the influence of soil p H value, soil particle size, runoff volume, sediment amount,concentration of water-soluble heavy metals dissolved in runoff and insoluble absorbed to the soil particles. This model was reasonable in Huanjiang watershed, Guangxi Zhuang Autonomous Region, south China, covering an area of 273 km~2. The optimal drainage area threshold was determined by analyzing the effects of watershed subdivision on the simulation results to ensure the simulation accuracy. The main conclusions of this paper were:(1) watershed subdivision could affect simulation migration quantity of heavy metals;(2) the quantity of heavy metals transported by sediment accounted for 97%–99% of the total migration quantity in the study watershed. Therefore, sediment played the most important role in heavy metal migration;(3) the optimal drainage area threshold percentage to ensure high simulation accuracy was determined to be 2.01% of the total watershed;(4) with the optimal threshold percentage, this model could simulate the migration quantity of As, Pb and Cd accurately at the total watershed and subwatershed level. The results of this paper were useful for identifying the key regions with heavy metal migration.     

广州市酸沉降对材料破坏的经济损失估算

大气中的酸性物质对材料的破坏是酸沉降经济损失中的重要部分。简要说明了材料损失的计算方法,并以2001年为基准年,选择了广州市作为代表性城市,运用材料损伤函数和材料使用寿命公式对建筑材料及自行车的经济损失进行了估算,使酸沉降的破坏作用达到定量化。     

火灾下匀质防火保护钢构件温度计算(Ⅰ):理论与公式

介绍了火灾下有匀质防火层保护的钢构件温度计算的一维传热模型。给出了求解该模型的相关边界条件和假定,并给出求解该一维传热模型在不同边界条件下的解。通过分析三种典型防火材料保护下、截面系数不同的三种截面的升温,比较了由我国规范CECS200、欧洲规范、欧钢协标准、美国规范及其他学者推荐的方法得到的结果,并对照有限元结果,考察了不同计算方法的有效性。结果表明,CECS200与国外规范给出的结果符合良好且略微偏高。通过计算典型截面在不同耐火极限要求下的最小保护层厚度,比较了各国规范的设计结果。结果显示,由不同规范推荐的公式计算得到的最小保护层厚度相差不大。CECS200计算的最小保护层厚度与国外规范一致,与欧洲规范得到的结果基本相同。研究表明,在标准火灾环境中我国规范给出的方法合理有效且形式简单便于工程运用。     

跨座式单轨交通人身安全雷电防护分析

针对跨座式单轨交通列车遭受雷击时列车内的人员安全性,本文通过对列车内人员不接触与列车金属外壳直接连接的金属构件和接触与列车金属外壳直接连接的金属构件两种情况进行计算分析,得出第一种情况下,人员是完全安全的;第二种情况下,人员可能会有像蜜蜂刺痛或烟头灼痛的感觉,但不威胁生命安全。     

采煤工作面漏风通道参数研究与应用

采煤工作面漏风会导致采空区缓慢自燃氧化以及有毒有害气体涌入工作面,造成采空区自然发火及工作面工作人员中毒窒息的可能性.工作面不同进风风量下工作面漏风情况会不同.为了具体研究工作面不同进风风量下的漏风情况,测定了元堡煤矿1901工作面停采期间各漏风通道的漏风量,建立了工作面漏风通道网络模型;根据风网解算原理及风阻计算公式计算出各分支风阻及风量值;利用风网解算软件计算出不同风量下工作面漏风通道的风量值.结果发现:元堡煤矿1901工作面风量在500 - 1500m3/min范围内变化时各漏风通道风量占工作面总进风量的比重几乎不变;采空区两巷由于已经打好密闭,漏风较小;工作面中部由于老顶来压漏风量较大,是堵漏风重点.