The role of microstructure on the mechanical properties of polyurethane foams containing thermoregulating microcapsules

Rigid polyurethane foams with up to 50 wt% of microcapsules from LDPE-EVA containing Rubitherm^®RT27 were synthesized. The influence of microcapsules on the foams density, microstructure and mechanical resistance was studied. Cell size and strut and wall thicknesses were analyzed by SEM. The relationships between densities and foam microstructures with their Young's moduli and collapse stress were found by the Gibson and Ashby formulations and the Kerner equation for mechanical properties of composites. It was found a cell structure change from polyhedral closed-cells to spherical or amorphous open-cells. A good agreement between the experimental and theoretical data was observed but requiring a cell form factor. Thus, Fitting parameters confirmed the high trend of these microcapsules to be incorporated into the foam cell walls and the form factors depicted the abrupt change of cell morphology. Thus, these equations are suitable for predicting the mechanical properties of foams containing fillers of low mechanical resistance.     

基于“学习金字塔理论”的物理化学实验教学模式改革实践

介绍了东北林业大学物理化学实验课程教学中基于"学习金字塔理论"进行教学模式改革实践的情况。在实施实验教学过程中,通过增加"学生通过在线实验视频预习""学生为学生讲解实验""操作前学生小组讨论"和"操作后学生小组总结讨论"等学习环节,建立了一种有效的"以学生为中心"的实验教学模式,促进了学生综合素质和创新能力的培养,取得了良好的教学效果。     

含公共开支的两部门内生经济增长模型

本文研究了一个含公共开支的两部门的内生经济增长模型 ,其生产函数具有最一般的形式 .用于两部分的三要素—物质资本 ,人力资本 ,有效劳动的份额正相关 ,产出用于公共开支的份额与用于生产部门的三要素的份额负相关 ,经济增长极大地依赖于生产弹性 .并给出均衡值为正的条件和经济系统沿二维稳定流形收敛于稳定点的条件     

体力活动对围绝经期女性更年期综合征影响的研究

目的研究体力活动对围绝经期女性更年期综合征的影响。方法2013年8月至2014年8月通过院内调查及社会调查两种模式共调查杭州市余杭区472例围绝经期女性,调查资料完整者401例,其中符合纳入标准者223例,通过问卷形式收集患者一般情况（包括年龄、身高、体重、吸烟饮酒情况、生育情况等）、更年期综合征症状、体力活动强度。分析患者体力活动与更年期综合征的关系。结果在文化水平、初次月经、年龄等方面,轻、中、重体力活动组之间无统计学差异（均P＞0.05）;轻度体力活动组BMI＞25的比例为26.5%,吸烟比例为32.5%,饮酒比例为27.7%,均高于中、重度体力活动组的相应比例（均P＜0.05）。轻度及重度体力活动组血管舒缩分值高于中度体力活动组（P＜0.05）,但轻度体力活动组与重度体力活动组比较差异无统计学意义（P＞0.05）,在心理社会、性生活、生理状态上,轻度体力活动组分值均高于中度及重度体力活动组,差异均有统计学意义（均P＜0.05）,中度体力活动组与重度体力活动组间比较均无统计学差异（均P＞0.05）。采用多元logistic回归分析绝经期生存质量状况与体力活动的关系,在校正BMI、文化水平、吸烟、饮酒、初次月经、婚姻状况、生育情况、工作状态、年龄等因素后,血管舒缩症状在中度体力活动组症状轻于轻度及重度体力活动组（P＜0.05）,重度体力活动组与轻度体力活动组无统计学统计学意义（P＞0.05）;心理社会、性生活及生理状态症状,中度及重度体力活动组症状均要轻于轻度体力组（P＜0.05）,中度与重度体力活动组间比较无统计学意义（P＞0.05）。结论体力活动的增加对围绝经期女性是潜在有意义的替代治疗方法,尤其是中度的体力活动可以在一定程度上预防或改善更年期综合征症状。     

地区经济发展的不平衡与经济增长

本文用两部门内生增长模型分析了在地区经济发展不平衡的情况下 ,经济发展的长期趋势 .在这个模型中 ,假定物质资本和人力资本可以不受限制的自由流动 ,技术是外生给定的 .研究发现 ,地区差别使发达地区的经济发展更快 ,落后地区的经济发展更慢 ;发达地区将有更高的均衡利率 .最后 ,文章给出了具体的政策建议 ,并对某些政策给予了评价 .     

B值鞅型序列的一些极限定理

本文讨论了一些B值鞅型序列的强大数定律 ,弱大数定律 ,Lr收敛性及完全收敛性 ,推广了许多熟知的结果 .     

关于分数次Marcinkiewicz积分在Hardy空间上的有界性

本文研究了核函数粗糙的分数次Marcinkiewicz积分μΩ,α在Hardy空间上的有界性.利用Hardy空间的原子分解定理,获得了算子μΩ,α的H1,Ln-nα型和(Hp,Lq)型的有界性结果.     

Laser induced threshold photoemission magnetic circular dichroism and its application to photoelectron microscope

This work enlightens the threshold photoemission magnetic circular dichroism (MCD) and its adaption on photoemission electron microscopy (PEEM) using lasers. MCD is a simple and efficient way to investigate magnetic properties since it does not need any spin analyzers with low efficiency, and thus the MCD related techniques have developed to observe magnetic domains. Usually, MCD in a total yield measurement in the valence band with weak spin–orbit coupling (SOC) excited by low photon energy (hν≤ 6 eV) does not compete with the X-ray magnetic circular dichroism (XMCD) with strong SOC. XMCD PEEM observation of magnetic domains has been successfully established while MCD PEEM derived from valence bands has not been. However, using angle and energy resolved photoelectron, valence band MCD provides large asymmetry similar to that by XMCD. Threshold measurement of photoelectron in a total electron yield procedure can take advantage of the measurement of photoelectrons with a limited angle and energy mode. This restriction of the photoelectron makes the threshold MCD technique an efficient way to get magnetic information and gives more than 10% asymmetry for Ni/Cu(0 0 1), which is comparable to that obtained by angle resolved photoemission. Thus the threshold MCD technique is a suitable method to observe magnetic domains by PEEM. For threshold MCD, incident angle dependence and high sensitivity to out-of-plane magnetized films compared with in-plane ones are discussed. Ultrashort pulse lasers make it feasible to measure two photon photoemission MCD combined with PEEM, where resonant excitation has a possibility to enhance dichroic asymmetry. Recent results for valence band magnetic dichroism PEEM are presented.     

Effects of Physical Agents on Muscle Healing with a Focus on Animal Model Research

Skeletal muscle injury is caused by a variety of events, such as muscle laceration, contusions, or strain. Muscle fibers respond to minor damage with immediate repair mechanisms that reseal the cell membrane. On the other hand, repair of irreversibly damaged fibers is achieved by activation of muscle precursor cells. Muscle repair is not always perfect, especially after severe damage, and can lead to excessive fibroblast proliferation that results in the formation of scar tissue within muscle fibers. Remaining scar tissue can impair joint movement, reduce muscular strength, and inhibit exercise ability; therefore, to restore muscle function, minimizing the extent of injury and promoting muscle regeneration are necessary. Various physical agents, such as cold, thermal, electrical stimulation, and low-intensity pulsed ultrasound therapy, have been reported as treatments for muscle healing. Although approaches based on the muscle regeneration process have been under development, the most efficacious physiological treatment for muscle injury remains unclear. In this review, the influence of these physical agents on muscle injury is described with a focus on research using animal models.