大气污染与天空的颜色

 自然界中绚丽多彩的晚霞和日出东方时的壮观景象是任何一位艺术家都难以描绘的。但是很少人知道我们目睹的大部分落日的颜色是大气污染造成的。城市的落日和空气清新的乡村落日不同。     

含二烯丙基双酚A醚相容剂对HDPE/PC共混体系的影响

用低密度聚乙烯接枝二烯丙基双酚Ａ醚（ＬＤＰＥ ｇ ＤＢＡＥ）作为高密度聚乙烯／聚碳酸酯（ＨＤＰＥ／ＰＣ）共混体系的增容剂,研究了其对ＨＤＰＥ／ＰＣ共混体系的影响．通过共混物形态观察、热力学性能测试和结晶性分析,发现ＬＤＰＥ ｇ ＤＢＡＥ对ＨＤＰＥ／ＰＣ共混体系有良好的增容效果．并发现了增容剂在共混物中的最佳用量为１０ｐｈｒ,提高增容剂的接枝率更有利于改善共混物的性能     

致密类乳腺病变不同影像学检查方案的效果评价

结合卫生经济评价致密类乳腺超声、钼靶、磁共振不同影像学检查单一或联合方案的诊断效能。回顾性分析行手术或穿刺活检的致密类乳腺130例134个病灶患者资料,所有患者均在术前2周内完成超声、钼靶及磁共振检查。结果显示单一检查方案钼靶对致密类乳腺病变诊断价值有限,磁共振诊断敏感度及特异度高,但成本-效果比高(4.84),不适合做普查,超声敏感度高,成本-效果比最低(0.99),可作为首选检查,但特异度不足,需要补充检查提高诊断效果。联合方案超声+磁共振准确度最高,增量成本-效果比最低,从卫生经济学角度在联合方案中为最优化方案。致密类乳腺超声发现可疑病变,再联合应用磁共振检查,能显著提高诊断效能。     

紫外分光光度法在检测磁化效果中的应用

用紫外分光光度法对几种物质分别作了经前后的吸收光谱,发现物质受磁化后其吸收峰的位置不变,但吸收强度发生了不同程度的变化,而且不同的磁化时间有不同的磁化效果。     

如何提高《力学》课堂教学效果的探析

学生由中学进入大学学习方法和思维方法的转变很重要．力学是物理学专业的第一门基础课,占有很重要的地位,因此如何提高力学的教学效果通过力学教学培养学生的学习能力和思维方法,从而为后继课程的学习打下基础,是力学教学特别重视的问题．下面结合作者的教学实践分析如何提高课堂教学效果,培养学生的学习能力和思维方法．     

Influence of laser mode on splitting beam illumination effect of Dammann grating

The influences of various laser modes on the splitting beam effect of Dammann grating are studied in theory and by numerical simulation. The results show that fundamental mode laser resembles plane wave while high order mode laser differs from plane wave in the splitting beam effect by Dammann grating. Therefore, the fundamental mode laser is more suitable to be the light source to improve the energy efficiency in far-distance image detecting systems, such as laser image ladar, which use Dammann grating in the ilhlmination svstem.     

目标红外迷彩伪装技术研究

随着红外迷彩伪装涂料的出现,利用其对目标红外热图像进行分割,破坏目标图像特征的特点,为目标红外对抗提供了一种新的有效手段.首先,以传热模型为基础,模拟出目标的表面温度,并通过实测得出背景的表面瞬态温度.然后,利用随机生成的方法,生成背景的红外纹理图像.最后,以目标与背景的辐射对比度为基础,对红外迷彩涂料的设计参数进行了优化,分析了红外迷彩涂料的设计参数和图案设计对目标伪装效果的影响,达到了较好的红外伪装效果.     

Lattice Boltzmann Simulation of the Cross Flow Over a Cantilevered and Longitudinally Vibrating Circular Cylinder

The multiple-relaxation-time lattice Boltzmann method （MRT-LBM） is implemented to numerically simulate the cross flow over a longitudinal vibrating circular cylinder. This research is carried out on a three-dimensional （3D） finite cantilevered cylinder to investigate the effect of forced vibration on the wake characteristics and the 3D effect of a cantilevered cylinder. To meet the accuracy of this method, the present calculation is carried out at a low Reynolds number Re =100, as well as to make the vibration obvious, we make the vibration strong enough. The calculation results indicate that the vibration has significant influence on the wake characteristics. When the vibrating is big enough, our early works show that the 2D vortex shedding would be locked up by vibration. Contrarily, this phenomenon would not appear in the present 3D case because of the end effect of the cantilevered cylinder.     

Training Effect and Hysteretic Behaviour of Angular Dependence of Exchange Bias in Co/IrMn Bilayers

The training effect and the hysteresis behaviour of the angular dependence of exchange bias are extensively investigated upon the variation of the IrMn layer thickness tXrMn in a series of Co/IrMn bilayers. When tIrMn is very small, both of them are negligible. Then they increase very sharply with increasing tUMn and then reach maxima at almost the same value OftXrMn. Finally they both decrease when tIrMn is further increased. The similar variation trends suggest that these phenomena arise from irreversible change of antiferromagnet spin orientations, according to the thermal activation model.     

对加强和改进大学物理教学中多媒体技术的探讨

论述了理工科学生学习大学物理的必要性和重要性,阐述了多媒体技术对提高大学物理教学效果的特殊作用;分析了目前大学物理多媒体技术应用的现状和存在的主要问题,以及应该采取的改进措施和努力方向;提出了将多媒体技术的长处与传统教学模式的优点有机结合,进一步提高大学物理教学效果的观点．