爆破参数对爆破块度效果影响的灰色关联分析

根据爆破块度预测模型存在的问题，结合一组爆破试验，分析了最小抵抗线、炮孔密集系数、炸药单耗等爆破参数对爆破块度效果的影响，得出了这些因素影响程度的关联序，为爆破参数的合理选择提供了借鉴。     

中国小城镇产业聚集成因及问题分析

随着全球化进程的日益加快,产业聚集现象受到国内外学者的普遍关注。小城镇产业聚集的健康发展对于加快中国城镇化建设、增强国际竞争力、应对全球化挑战具有重大意义。本文从小城镇的角度并侧重农产品加工产业,对产业聚集的类型、特征、成因、存在问题、对策及小城镇产业聚集进行了分析。     

孔隙比与红土物理力学参数的相关性

红土中的孔隙会影响其物理力学性质 ,孔隙比对其含水能力、可塑性、紧密程度有较大影响 ,孔隙比与含水量、比重、液塑限、压缩系数、凝聚力等指标呈线性正相关关系 ,与干密度、湿容重呈线性负相关关系 ,对含水状态、颗粒相互错动能力以及孔隙连通情况的直接影响较小     

新汶矿区煤炭发热量与灰分的相关关系及其应用

对新汶矿区煤炭发热量和灰分的相关性进行了分析,由此推导出的回归方程可应用于实际工作中换算该矿区煤炭的干基高位发热量和收到基低位发热量。     

几种伪码体制引信的抗噪声性能分析

简单介绍了伪码调相引信,伪码调相与脉冲幅度调制(PAM)复合引信,伪码调相与（伪）随机脉冲位置调制(PPM)复合引信的工作原理。推导出它们从带通滤波后至相关检测前这一过程中信号处理方面的信噪比增益,以及至相关检测后整个过程中信号处理方面的总信噪比增益。结果表明后两种引信具有相同的抗噪声性能,且均强于伪码调相引信。     

铝合金偏心受压构件理论和试验研究

进行了45个国产6061-T6铝合金挤压型材的偏心受压构件试验,搜集到了12个已有同类试验数据。通过对国产铝合金偏心受压构件进行大规模数值计算,得到了1920条偏压构件弯曲失稳的相关曲线。在此基础上,将常用截面类型分为了三类,并拟合出了计算三类截面偏压构件弯曲失稳的精确相关公式,同时也拟合出了适用于所有截面类型的下限相关公式。最后,将拟合公式和试验数据进行了比较。结果表明:所有试验点均高于下限相关曲线,而和精确相关曲线十分接近。因此,本文提出的公式能够用于计算铝合金偏心受压构件的弯曲失稳极限承载力。     

砌体抗剪强度研究的回顾与新的计算方法

通过单砖砌体模型双剪试验研究了砌体剪压复合受力相关性，证实了随轴压比的增加，按摩尔和库仑两种理论计算值与实际抗剪强度相差越来越大的原因在于二者分别过低和过高仨计了砌体抗剪能力，因而，提出了新的计算方法，以期准确确定任意压力下砌体的抗剪强度。此外，亦提出了尚需研究的若干问题。     

合肥地区粘性土的自由膨胀率与液限的关系

文章从试验资料出发,对合肥地区粘性土的自由膨胀率与液限的相互关系进行统计分析,建立线性方程,根据方程由液限算出自由膨胀率,结合工程地质特征,可对粘性土的膨胀性进行判定。     

Cell type specificity of lung cancer associated with air pollution

The aim of this study is to explore whether lung cancer associated with air pollution has cell type specificity. The air quality data (SO(2), CO, O(3), NOx) from the Taiwan EPA's air quality monitoring stations were collected between 1995 and 1998. Patients with lung cancer were identified through the National Cancer Registration Program operated by the Taiwanese government. Two major pathological types (adenocarcinoma (AC) and squamous cell carcinoma (SCC)) were considered. The Pearson correlation coefficients between the air quality index and age-standardized incidence rate per 100,000 person years (ASR) of AC and SCC were calculated for both genders for three township categories characterized by different levels of air pollution. The traffic-related NOx and CO showed significant correlations with female lung cancer incidence rate, with Pearson's correlation 0.33 (P=0.03) and 0.40 (P=0.01) respectively. However, the correlation between air pollution and lung cancer was not significant for males. Significant correlation coefficients were also found between the ratio of AC/SCC and the mean concentrations of NOx (r=0.41, P=0.04) and CO (r=0.47, P=0.02) in females. Our results show that the worse the air pollution was in the area, the higher the AC rate, regardless of gender. On the other hand, SCC incidence rates did not increase with increasing air pollution. Our results show that a correlation exists between air pollution and lung adenocarcinoma incidence.     

Characterization of spectral responses of humic substances upon UV irradiation using two-dimensional correlation spectroscopy

The spectral responses of a leaf litter derived humic substance (LLHS) and Suwannee River fulvic acid (SRFA) upon ultraviolet (UV) A irradiation were characterized using two-dimensional correlation spectroscopy (2D-COS) based on the absorption and the synchronous fluorescence spectra at different irradiation times. A 12 day irradiation on the humic substances (HS) resulted in higher reduction of the absorbance relative to the dissolved organic carbon concentration, suggesting that aromatic chromophores were preferentially oxidized and/or non UV-absorbing compounds were generated by the photobleaching. Synchronous fluorescence spectra revealed the preferential removal of fulvic-like and humic-like fluorophores and delayed response of protein-like fluorescence upon the irradiation. The spectral features at long wavelengths (>430 nm) appear to be affected by intra-molecular interactions of the individual chromophores associated with shorter wavelengths. Absorption-based 2D-COS demonstrated that there are three types of absorption bands for the two HS, which changed sequentially in the order of 290-400 nm → 200-250 nm → 250-290 nm. In addition, two or three distinctive fluorescence bands in response to the irradiation were identified from 2D-COS. The sequential orders and the associated wavelength bands were possibly explained by the irradiation wavelengths and the differences between direct and indirect photochemical reactions. The interpretation of the 2D-COS results was very consistent with the kinetic rate constants individually calculated at several discrete wavelengths. Our study demonstrated that 2D-COS could be used as a powerful tool in identifying distinctive bands of HS that have dissimilar behavior and the associated sequential orders by visualizing the spectral changes at continuous wavelengths.