港口狭缝衍射边值问题的近似匹配法

对于入港口具有长而薄的狭缝孔道开口的衍射情形，研究通过狭缝衍射边值问题远场解与近场解的匹配问题。建立一种具有广泛意义的近似匹配方法，不仅得到与「１，２」类似的结果，而且具有二阶意义的近似性。     

用柱面波模型探讨地震电磁信息

本文从理论上探讨了地壳波导中传播的柱面电磁波,发现地震电磁波没有TM型波,这一特点可以用来识别地震电磁信号,引入衰减因子后,得到kr<1的区域,高导电层的衰减随频率的升高而减小,从而可以定性地解释观测到高频地震电磁信息的现象。     

漂浮育苗不同基质对烤烟苗生长的影响

为降低不可再生资源草炭的开采,采用漂浮育苗方式,研究河砂、河泥沙、山沙和常规基质共4种基质对烤烟烟苗生长的影响.结果表明,河砂、河泥沙和常规基质出苗率都高于90%,螺旋根发生率小于2%;河砂、常规基质利于根系生长,烟苗一级侧根数、二级侧根数和根系体积表现最佳的为河砂基质;河泥沙和常规基质在播种40d后烟苗硝酸还原酶(NR)活性高于河砂和山沙基质;地上、地下部干鲜质量以常规基质和河砂基质较大;河砂和山沙基质烟苗根系活力较高.常规基质的烟苗素质优于其他3种,同时也表明河砂基质具有较好的烟苗素质,而河泥沙基质的烟苗素质相对较差.     

武陵山片区恩施州文化软实力与旅游业互动发展研究

在文化软实力与旅游业互动的基础上,选用2000~2012年恩施州的相关经济数据指标,使用向量回归模型,通过数据平稳性检验、Johansen协整检验和Granger因果关系检验,实证分析了恩施州旅游业与文化软实力具体指标间有明确的互动关系,并由此给出了发展旅游业的政策性建议.     

蠕虫减量剩余活性污泥反应器的CFD数值模拟

构建以序批式反应器(SBR)为主体工艺并联合蠕虫反应器的生活污水处理系统,在保证系统出水水质达标的前提下,蠕虫对SBR产生的剩余活性污泥摄食减量约23%(以质量计)。利用ANSYS FLUENT 16.0软件提供的欧拉两相流模型和标准k-ε湍流模型,对蠕虫反应器内部速度场、含气率以及湍流强度等进行了计算流体动力学(CFD)数值模拟。模拟结果表明,蠕虫反应器内曝气量约为0.2m₃/h、 蠕虫投放在P2位置即蠕虫密度为1.63g/dm₃时,蠕虫反应器内部流场适合蠕虫减量污泥,减质最高达23%,与试验结果基本吻合。通过响应曲面法(BBD)进行试验,所得污泥减量率与BBD预测值基本相符,进一步佐证了数值模拟结果的可靠性。因此,利用CFD数值模拟可以指导蠕虫反应器优化运行,从而为蠕虫减量污泥系统的放大设计及工程应用奠定基础。     

溶解性有机质-四环素-Zn共存体系中土壤对四环素和Zn的吸附作用

以畜禽粪便中的典型组分——溶解性有机质、四环素和锌作为研究对象,以东北典型黑土为供试土壤,采用批次实验法,研究了溶解性有机质、四环素和锌三元混合体系中土壤对四环素和锌的吸附作用。结果表明,土壤对四环素的吸附符合Freundlich吸附模型,土壤对Zn的吸附既符合Langmuir吸附模型,也符合Freundlich吸附模型;四环素和锌之间存在着相互促进吸附的作用;溶解性有机质抑制了四环素在土壤上的吸附,促进了Zn在土壤上的吸附;在溶解性有机质-四环素-Zn混合体系中,四环素和溶解性有机质共存促进了Zn的吸附;而对于四环素的吸附,溶解性有机质和Zn的共存可以表现为促进作用,也可以表现为抑制作用,二者的相对浓度是决定其作用的关键因素。     

Design and optimization of transparent scattering solar concentrator based on SiO2 aerogel

Scattering solar concentrators (SSCs), an important component of transparent/translucent photovoltaic devices, can concentrate large-area sunlight on small-area solar cells while allowing some sunlight to pass through the devices. However, owing to the lack of suitable scattering materials, there have been few reports on SSCs in recent years. In this study, we fabricated SiO₂ aerogel-based SSCs and tested their performances. The photoelectric performance was found to be moderate. Additionally, the results demonstrated excellent transmittance and color rendering index, which meet the lighting requirements of the windows. A Monte Carlo ray tracing program was developed to simulate an SSC and analyze the fate of all photons. We also analyzed the multiple scattering mechanism in SSCs that damages the photoelectric efficiency of a device via theoretical simulation. Finally, we proposed an anisotropic scattering device that can increase the primary scattering and suppress multiple scattering, resulting in excellent photoelectric efficiency.     

Azimuth resolution improvement for spaceborne SAR images with quasi-non-overlapped Doppler bandwidth

The azimuth resolution improvement problem is solved via a coherent combination of synthetic aperture radar （SAR） ima-ges with the quasi-non-overlapped Doppler bandwidth. Prior to the spectra combination, SAR images should be coregistered, while phase biases induced by topography, atmospheric propagation delays and baseline measurement errors should be calibrated. However, the coregistration accuracy suffers from large Doppler decorrelation caused by the quasi-non-overlapped Doppler band-width. Furthermore, the method used to estimate phase biases from interferogram of azimuth prefiltered SAR image pairs wil fail when there is no overlapped spectrum. The fringe simulation and maximum sharpness optimization are adopted to deal with the problems. Accordingly, a novel algorithm to coherently synthesize SAR images is presented. The experiment with the Terra SAR X-band （TerraSAR-X） satel ite data validates the performance of the presented method.     

Dynamics of individual flexible polymers in a shear flow.

Polymer dynamics are of central importance in materials science, mechanical engineering, biology and medicine. The dynamics of macromolecular solutions and melts in shear flow are typically studied using bulk experimental methods such as light and neutron scattering and birefringence. But the effect of shear on the conformation and dynamics of individual polymers is still not well understood. Here we describe observations of the real-time dynamics of individual, flexible polymers (fluorescently labelled DNA molecules) under a shear flow. The sheared polymers exhibit many types of extended conformation with an overall orientation ranging from parallel to perpendicular with respect to the flow direction. For shear rates much smaller than the inverse of the relaxation time of the molecule, the relative populations of these two main types of conformation are controlled by the rate of the shear flow. These results question the adequacy of assumptions made in standard models of polymer dynamics.