脱硝设备入口NOx浓度经济值的控制

介绍了应用最为广泛的低NO_x空气分级燃烧技术的间接运行费用与锅炉尾部烟气脱硝设备（脱硝设备）消耗还原剂的直接运行费用的计算方法,建立了两者配套应用时锅炉NO_x减排总费用的关系式;并按照NO_x减排总费用最小的原则,将脱硝设备入口NO_x浓度作为变量,提出了两者配套应用时脱硝设备入口必然存在NO_x浓度经济值的观点。主要结论为：脱硝设备入口NO_x浓度经济值是合理分配炉内空气分级燃烧技术的间接运行费用与脱硝设备直接运行费用的关键参数,NO_x浓度只有在该经济值下,NO_x减排的总费用才是最低的。     

某库岸滑坡的成因机制及稳定性

某库岸为典型高山峡谷地貌,斜坡在卸荷作用和重力作用下弯曲拉裂,形成规模巨大的滑坡。水库蓄水后,滑坡可能产生复活,将造成“二道坝”,危及大坝及其它枢纽建筑的安全。结合滑坡区的环境地质条件,滑坡的地质结构特征,分析其形成机制,并在此基础上建立地质 力学模型,再现滑坡形成过程。最后采用定量计算、数值模拟法计算滑坡安全系数、应力分布状态等,对滑坡蓄水条件下的变形及稳定性进行研究和预测,从而为滑坡治理工程设计提供依据。     

浩坤水电站水库喀斯特渗漏分析

介绍浩坤水电站库区水文地质、工程地质条件及喀斯特发育特征,结合连通试验成果和水位观测资料,对浩坤水电站库区喀斯特渗漏问题进行分析论证,提出防渗处理措施,评价是否具备成库条件。     

基于脑电模糊分析的睡眠分期方法研究

利用脑电信号模糊特征分类的方法对睡眠进行分期研究。首先对脑电信号进行预处理,滤除干扰噪声后使用模糊熵算法、多尺度熵算法以及复杂度算法对脑电信号进行特征参数提取,采用最小二乘支持向量机（the Least Squares Support Vector Machine,LS-SVM）对特征参数进行分类,并将睡眠过程分为清醒期、浅睡期、深睡期和快速眼动期（Rapid Eye Movement,REM）,获得分期正确率。最后通过上述方法对2?000组睡眠脑电样本进行睡眠分期测试,与专家人工分期结果进行比对,将复杂度输入到最小二乘支持向量机进行分类的平均正确率是92.65%,高于模糊熵和多尺度熵作为最小二乘向量机的输入时的准确率。基于模糊特征的复杂度提取的特征参数可以作为睡眠分期的有效依据,在保证准确度的前提下,降低人工成本。     

Detailed measurements in a pulverized-coal-fired large-scale laboratory furnace with air staging

The aim of the present work was to evaluate the performance of a pulverized-coal-fired large-scale laboratory furnace with air staging. New data are reported for gas phase species concentration, temperature and particle burnout for two primary zone stoichiometric ratios, 1.15 (unstaged flame) and 0.95 (staged flame), other operating conditions being fixed. The results revealed that the reduction in primary zone stoichiometric ratio caused a decrease in NO_x emissions from 421 to 180 mg/N m³@6%O₂, an increase in CO emissions from 51 to 168 mg/N m³@6%O₂ and a reduction in particle burnout from 81.8% to 76.5%. It was concluded that the reduction of the O₂ availability in the primary zone inhibits the NO formation, mainly via the fuel mechanism, but it affects negatively both the CO and the char oxidation processes because, under staging conditions, both processes tend to occur in the vicinity of the over fire air injection region, where the temperatures are relatively low.     

基于分布式光纤测温的高拱坝蓄水初期实测温度场分析

蓄水初期坝体内部实际温度分布状态对高拱坝的安全运行具有重要意义,基于分布式光纤测温原理,运用sufer8.0绘图软件绘制各蓄水阶段的拱冠梁坝段实测温度等值线图,根据温度等值图可直观分析坝体内的温度场分布状态,并结合西南某高拱坝施工期及蓄水初期光纤实测温度资料,判断得出该高拱坝坝体温度场分布大致合理,温度控制措施合理有效。由此表明,基于分布式光纤测温方法简单、结果可靠,可满足实际现场运行监测需要。     

向家坝下游高边坡蓄水前后外观变形空间聚集性态对比分析

水库蓄水会对周围工程与地质环境造成较大的影响,严重时甚至会引起岸体滑坡。基于空间计量学全局和局部空间自相关系数及其相关分析方法,以向家坝坝体下游坝后左岸人工高边坡为例,在传统研究只考虑二维坐标的情况下,进一步考虑不同测点的三维空间坐标,建立了考虑空间坐标的空间权重矩阵,计算了各个蓄水时段高边坡不同测点的外观变形数据的全局和局部空间自相关系数;对比了不同蓄水时段下游边坡外观变形的空间聚集性态,从而定位高边坡变形监测关键测点。研究结果表明:2种空间自相关系数可以有效探测变形数据的聚集程度,识别聚集区域;水库蓄水会在下游坡形成明显的空间聚集性变形,尤其是在蓄水初期变化最为剧烈,需要在该阶段加强观测。     

锅炉降低NOx排放改造

热电分公司地处北京市中心,其特殊的地理位置使其必须将环境保护问题放在首位。为此特别介绍了热电分公司为降低锅炉NOX排放所进行的设备改造和燃烧方式的调整及其取得的效果。     

The role of endorectal coil MRI in preoperative staging and decision-making for the treatment of clinically localized prostate cancer

Introduction  The optimal management of newly diagnosed prostate cancer requires individualization of the treatment plan based upon the most accurate clinical characterization of tumor location and extent of disease. The role of imaging in prostate cancer staging continues to evolve. In this review, we address the utility of endorectal coil magnetic resonance imaging (eMRI) in both local staging and its ability to facilitate the decision in choosing one treatment strategy over another after the initial diagnosis of localized prostate cancer. Materials and methods  Using the PubMed database and reference lists of key articles, we identified studies addressing the use of eMRI in tumor characterization and risk stratification in patients undergoing treatment for clinically localized prostate cancer. Results  The findings identified within 54 selected studies were incorporated into a summary discussing the current limitations in cancer staging and the role eMRI plays in both the preoperative assessment and clinical decision-making in an attempt to improve our ability to individualize management approaches and tailor treatment. Conclusion  eMRI allows for more accurate local staging by complementing the existing clinical variables through improvements in spatial characterization of the prostatic zonal anatomy and molecular changes. These improvements in tumor staging enhance our ability to individualize treatment selection and tailor the approach to maximize cancer control while minimizing treatment related morbidity.     

Declines in aquatic vegetation in navigation pool no. 8, upper Mississippi River between 1975 and 1991

The biomass and frequency of occurrence of aquatic macrophytes observed during 1975 and 1991 in Navigation Pool No. 8 of the upper Mississippi River were compared. Samples were collected from contiguous backwater, isolated backwater and impounded habitat types. Overall declines were observed in both frequency and biomass between the two years. Changes in depth, water clarity and bed sediment texture were also observed. About 50% of the samples collected in 1991 had no vegetation, compared with 20% in 1975. The greatest reduction in frequency occurred among submergent taxa (77% in 1975 to 31% in 1991), whereas only slight declines were observed for emergent taxa. However, the mean biomass of both lifeforms decreased substantially (48 to 1 g/m² for submergent and 61 to 27 g/m² for emergent lifeforms). The mean total biomass declined from 114g/m² in 1975 to 35 g/m² in 1991. Declines were most evident in the impounded habitat, where the frequency of occurrence of submergent taxa decreased from 83% in 1975 to 11% in 1991, and mean biomass decreased from 90 to 1 g/m². Similar but less extensive reductions in frequency and biomass of submergent taxa were observed in the contiguous backwater habitat. In contrast, both the frequency and biomass of floating-leaved macrophytes increased slightly in contiguous backwater habitats. Changes in frequency and biomass of macrophytes in isolated backwater habitats were neligible between 1975 and 1991. It is hypothesized that changes in the macrophyte community structure may be related to physical changes associated with 57 years of impoundment.