单纯钻孔引流与神经内镜辅助治疗慢性硬膜下血肿的临床分析

目的探讨单纯钻孔引流与神经内镜辅助治疗慢性硬膜下血肿的临床疗效。方法将我院自2011年05月至2013年05月应用单纯钻孔引流治疗的54例慢性硬膜下血肿患者作为对照组,将我院自2013年05月购入神经内镜后至2015年05月应用神经内镜辅助下治疗的52例慢性硬膜下血肿患者作为实验组,应用改良Markwalder分级评定神经功能,回顾性对比分析两组患者在年龄、性别等一般资料及术前、术后改良Markwalder分级、手术时间、住院时间、复发率方面的差异,评价临床疗效。结果两组患者的一般资料无明显差别(P>0.05)。两组患者术后神经功能较术前均有好转(P<0.05),但术后好转程度无明显区别(P>0.05)。实验组较对照组手术时间长、住院时间短、术后复发率低(P<0.05)。结论与单纯钻孔引流相比,神经内镜辅助治疗慢性硬膜下血肿在减少住院时间、降低复发率方面有优势。

Thermodynamic and Optical Properties of CuAlO_2 under Pressure from First Principle

The structural stability, thermodynamic and optical properties of delafossite CuAlO2 were investigated using the norm-conserving pseudopotential technique based on the fi rst-principle density-functional theory. The ground-state properties obtained by minimizing the total energy were in favorable agreement with previous works. By using the quasi-harmonic Debye model, the thermodynamic properties including the Debye temperature QD, heat capacity CV, thermal expansion coeffi cient a, and Grüneisen parameter g were successfully obtained in the temperature range from 0 to 1 000 K and pressure range from 0 to 80 GPa, respectively. The optical properties including dielectric function e（v）, absorption coeffi cient a（v）, refl ectivity coeffi cient R（v）, and refractive index n（v） were also calculated and analyzed.

硅改性酚醛树脂物理性能的分子动力学模拟

采用分子动力学模拟方法研究纳米SiO2以及甲基苯基二甲氧基硅烷改性酚醛树脂的物理性能。研究表明:300 K下未改性酚醛树脂玻璃转化温度为362 K,弹性模量、剪切模量分别为5.45 GPa和2.19 GPa,热导率和热膨胀系数分别为0.37 W·(m·k)-1和3.8×10-5 K-1,添加纳米SiO2后玻璃转化温度提高了1.6%,弹性模量、剪切模量分别提高了34.9%和28.8%,热导率和热膨胀率分别降低了11%和31.6%。SiO2表面接枝3%、5%、7%和10%硅烷偶联剂以及甲基苯基二甲氧基硅烷改性酚醛树脂玻璃转化温度分别提高了10.5%、15.2%、16.8%、19.3%和1.5%,弹性模量分别提高了44.4%、53.2%、53.8%、63.5%和13.4%,而热导率分别降低了12.4%、13.5%、11.2%、7%和10%。此外甲基苯基二甲氧基硅烷改性的酚醛树脂的热膨胀系数较未改性酚醛树脂提高15.7%。研究表明:掺杂纳米SiO2、SiO2表面接枝硅烷偶联剂以及甲基苯基二甲氧基硅烷改性都能够提高酚醛树脂的玻璃转化温度,机械性能同时降低热导率,而对于热膨胀系数,纳米SiO2掺杂使其减小,甲基苯基二甲氧基硅烷改性则会使其明显增大。

Molecular dynamics study on the relationships of modeling,structural and energy properties with sensitivity for RDX-based PBXs

In this paper,a primary model is established for MD(molecular dynamics) simulation for the PBXs(polymer-bonded explosives) with RDX(cyclotrimethylene trinitramine) as base explosive and PS as polymer binder.A series of results from the MD simulation are compared between two PBX models,which are represented by PBX1 and PBX2,respectively,including one PS molecular chain having 46 repeating units and two PS molecular chains with each having 23 repeating units.It has been found that their structural,interaction energy and mechanical properties are basically consistent between the two models.A systematic MD study for the PBX2 is performed under NPT conditions at five different temperatures,i.e.,195 K,245 K,295 K,345 K,and 395 K.We have found that with the temperature increase,the maximum bond length(L max) of RDX N N trigger bond increases,and the interaction energy(E N-N) between two N atoms of the N-N trigger bond and the cohesive energy density(CED) decrease.These phenomena agree with the experimental fact that the PBX becomes more sensitive as the temperature increases.Therefore,we propose to use the maximum bond length L max of the trigger bond of the easily decomposed and exploded component and the interaction energy E N-N of the two relevant atoms as theoretical criteria to judge or predict the relative degree of heat and impact sensitivity for the energetic composites such as PBXs and solid propellants.