连续配筋水泥混凝土路面的临界荷位

以三板系统模拟连续配筋水泥混凝土路面,计算获得了连续配筋路面的临界荷位.引入接缝混凝土板的传力杆设计理念,确定了连续配筋路面横向裂缝处钢筋的传荷刚度计算公式.同时,以有限元方法建立了CRCP横向裂缝处混凝土的传荷刚度计算公式.裂缝处传荷刚度的确定,为模拟CRCP荷载应力计算提供了关键参数.有限元数值计算表明：三板系统中,当边板长度大于4 m时,边界条件将不对应力计算产生影响.对于双车道路面,计算所得的板宽向最大应力位于左车道外侧车轮板底的轮迹中心处,此时的路面荷位为标准轴载位于路面右边边缘且靠近裂缝边缘,推荐此荷位作为路面承载力检验的核算位置.     

轮胎接触构造分布对沥青路面降噪特性的影响

从轮胎与路面的噪声产生机理出发,采用主驱动轮式路面功能评价系统开展不同级配的沥青路面噪声特性研究;并基于胎/路接触特性提出路面降噪效果的评价指标。结果表明:胎/路接触界面的开口空隙率可以有效评价路面空气泵吸作用;相比沥青混合料内部空隙率和路表构造深度,轮胎有效接触界面的开口空隙率与路面噪声相关性更高,路面噪声随着轮胎接触界面的开口空隙率的增加而降低。建议混合料设计时适当增加4. 75 mm以上的粗集料比例(4. 75 mm筛孔通过率推荐为30%～33%),有助于提高沥青路面开口构造比例及其长期稳定性。建立轮碾作用下的路表开口空隙率与噪声A计权声压级的相关性模型,其相关性显著性水平达到0. 001,进一步验证开口空隙率指标的合理性。研究可为低噪声沥青混合料级配设计与降噪效果评价提供参考依据。     

基于ADAMS的绳牵引并联支撑系统动力学建模

为了实现对低速风洞强迫振荡试验绳牵引并联支撑系统的精确控制,需要建立精确的动力学模型,分析系统的振动特性,避免共振.首先,提出适合低速风洞绳牵引并联支撑系统的线性弹簧理论,应用动力学分析软件 ADAMS搭建动力学三维模型;其次,通过对系统进行振动分析,得到系统固有频率满足强迫振荡试验要求的弹簧参数;然后,对系统进行受迫振动分析,结果表明系统符合振动规律,验证了系统建模的正确性;最后,将每根绳索离散为10段线性单元,并对系统进行模态分析,发现离散前后系统的固有频率值相近似,且满足强迫振荡试验要求,说明采用线性弹簧理论建立绳索动力学模型是可行的,为了简化建模,无需将绳索离散化.     

单位圆内高阶线性微分方程解与小函数的关系

利用亚纯函数的Nevanlinna的基本理论和方法,研究了系数是单位圆内的高阶齐次和非齐次线性微分方程解的复振荡,讨论了系数是单位圆内的解析函数的高阶齐次和非齐次线性微分方程的解及一次导数和二次导数与其小函数之间的关系,得到了单位圆内高阶齐次和非齐次线性微分方程的解取小函数的精确估计,推广和改进了以前一些文献的结论。     

平行板电极喷射电沉积中枝晶分形生长的研究

将分形几何与电化学原理相结合,通过改进的有限扩散凝聚模型(Diffusion-Limited Aggregation,DLA),采用基于Microsoft Visual C++ 6.0编程对平行板电极为阴极进行二维电沉积时沉积产物的形貌进行了模拟。以平行板金属镍为阳极,石墨板为阴极,用自行设计的试验设备,采用平行板电极喷射电沉积的方法,制备了二维的金属镍枝晶以验证模拟结果,结果表明,镍沉积层的形貌特征为具有分形结构的枝晶,这与采用DLA模型模拟所得的平行板电极二维枝晶形貌具有相似性,表明该模型对平行板电极电沉积的试验研究具有很好的指导意义。     

The Escherichia coli O157:H7 DNA detection on a gold nanoparticle-enhanced piezoelectric biosensor

This paper presents development of a quartz crystal microbalance (QCM) biosensor for real-time de- tection of E. coli O157:H7 DNA based on nanogold particles amplification. Many inner Au nanoparticles were immobilized onto the thioled surface of the Au electrode, then more specific thiolated sin- gle-stranded DNA (ssDNA) probes could be fixed through Au-SH bonding. The hybridization was in- duced by exposing the ssDNA probe to the complementary target DNA of E. coli O157:H7 gene eaeA, then resulted in a mass change and corresponding frequency shifts ( △f ) of the QCM. The outer avidin-coated Au nanoparticles could combine with the target DNA to increase the mass. The electro- chemical techniques, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were adopted to manifest and character each step. The target DNA corresponding to 2.0×103 colony forming unit (CFU)/mL E. coli O157:H7 cells can be detected by this biosensor, so it is practical to develop a sensitive and effective QCM biosensor for pathogenic bacteria detection based on specific DNA analy- sis. The piezoelectric biosensing system has potential for further applications, such as food safety and environment monitoring, and this approach lays the groundwork for incorporating the method into an integrated system for in-field bacteria detection.     

Preparation and luminescence characteristics of Sr3SiO5：Eu^2＋ phosphor for white LED

The Sr3SiO5：Eu^2＋ phosphor was synthesized by high temperature solid-state reaction. The emission spectrum of Sr3SiO5：Eu^2＋ shows two bands centered at 487 and 575 nm, which well agree with the theoretic values of emission spectrum. The excitation spectrum for 575 nm emission center has several excitation bands at 365, 418, 458 and 473 nm. And the results show that the emission spectrum of Sr3SiO5：Eu^2＋ is influenced by the Eu^2＋ concentration. The relative emission spectra of the white-emitting InGaN-based YAG：Ce^3＋ LED and Sr3SiO5：Eu^2＋ LED were investigated. The results show that the color development of InGaN-based Sr3SiO5：Eu^2＋ is better than that of InGaN-based YAG：Ce^3＋, and the CIE chromaticity of InGaN-based Sr3SiO5：Eu^2＋ is （x=0.348, y=0.326）.     

红色荧光粉KGd(WO4)2:Sm3+的制备及发光性能

采用高温固相法合成KGd(WO4)2:Sm3+荧光粉,样品在近紫外区404nm光激发下发射出Sm3+的特征光谱.通过X射线粉末衍射、荧光光谱等对其进行了表征,并分析了其发光特性,结果表明:在KGd(WO4)2:Sm3+中Sm3+离子最佳的掺杂量为5%(摩尔分数);烧结温度为1 000℃、助熔剂H3BO3的浓度为2%(摩尔分数)时,样品的发光强度最强.     

Characterization of codon usage bias in the dUTPase gene of duck enteritis virus

A comparative analysis of the codon usage bias in the newly discovered dUTPase gene （Assigned Accession No.： DQ486149） of the duck enteritis virus （DEV） and the dUTPase gene of 32 reference herpesviruses was performed. The results indicated that the DEV dUTPase gene encodes a protein of 477 amino acids, which includes five conserved motifs with a 3-1-2-4-5 arrangement. The codon adaptation index （CAI）, effective number of codons （ENC）, and GC3s values indicated synonymous codon usage bias in the dUTPase gene of herpesviruses, and this synonymous bias was correlated with host evolution. The codon usage patterns of the DEV dUTPase gene were phylogenetically conserved and similar to that of the dUTPase genes of the avian alphaherpesvirus. Although codon usage in each microorganism was different, there were no strain-specific differences among them. Sixty-one codons in the predicted polypeptide, with a strong bias towards A and T at the third codon position, were used. Comparison of the codon usage in the dUTPase gene of different organisms revealed that there were 19 codons showing distinct codon usage differences between the DEV and Escherichia coli dUTPase genes; 16 between the DEV and yeast dUTPase genes; and 15 between the DEV and human dUTPase genes. Analysis of variance （ANOVA） showed significant differences between the DEV and yeast dUTPase genes （r = 0.536, P 〈 0.01）. The extent of codon usage bias in the DEV dUTPase gene was highly correlated with the gene expression level, therefore the results may provide useful information for gene classification and functional studies.     

霍泉泉域水环境特征

总结了霍泉泉域范围、地质特征、泉域含水层特征,介绍了保护区范围,提出霍泉泉域岩溶水资源可开发利用性。