取证系统中数据恢复关键技术研究

磁盘中已删除文件在未被覆盖之前,其存储方式为连续和离散存储。针对连续存储提出了一种准确匹配已删除文件首簇高16位算法,并重点分析离散存储碎片,提出了一种基于部分匹配预测算法PPMC来重构磁盘上已删除文件碎片的模型。采用PPMC算法确定出任意两个碎片的相邻性概率值,然后再通过剪枝技术,将不可能的分支裁减,逐步加工处理,重构出一个有完整顺序的原文件。     

Biodegradable blends of poly(butylene adipate-co-terephthalate) and polyglycolic acid with enhanced mechanical,rheological and barrier performances

Blends of poly(butylene adipate-co-terephthalate)/polyglycolic acid (PBAT/PGA) were prepared by melt blending, in which PGA was used as reinforcing component. Impacts of PGA content on tensile property, microstructure, crystallization property, melt viscosity, barrier performance of the blends were researched. Compared with very soft behavior of PBAT, the tensile yield strength and modulus of PBAT/PGA (65/35) sample increased from 7.67, 62.6 MPa of neat PBAT to 12.05, 158.9 MPa, respectively. However, owing to poor PBAT/PGA interface compatibility, its elongation at break decreased significantly from 1082.1% to 88.7%. An epoxy chain extender (ADR) was used as reactive modifier to improve its interface compatibility and rheological property. The related physical properties of PBAT/PGA/ADR (65/35/x) samples with various ADR contents were evaluated in detail. It was found that ADR exerted relatively complex influences on the properties. Overall, compared with neat PBAT and PBAT/PGA (65/35) sample, the PBAT/PGA/ADR (65/35/x) samples exhibited better stiffness-ductility balance and higher processing stability.     

Ageing properties of polyurethane methacrylate and off‐stoichiometry thiol‐ene polymers after nitrogen and argon plasma treatment

Proprietary mixture of polyurethane methacrylate (PUMA) and off‐stoichiometry thiol‐ene (OSTE‐80) are evaluated as two possible polymeric substrates to prototype microfluidic biochips. Because of their lack of biocompatibility, PUMA and OSTE‐80 are modified by argon (Ar) or nitrogen (N₂) plasma treatment to introduce nitrogen moieties that are highly polar and conducive for cell attachment and growth. XPS and water contact angle measurement show that these nitrogen groups are relatively stable in the plasma‐treated PUMA and OSTE‐80 in spite of the hydrophobic recovery and volatilization of nitrogen moieties during air ageing for 15 days. This stability can be attributed to their high degree crosslinking that is reflected by the increase of elastic modulus of PUMA and OSTE‐80 during their air ageing. These results show that Ar and N₂ plasma‐treated PUMA and OSTE‐80 possess the necessary physical and chemical properties to be evaluated further to develop microfluidic biochips for biological applications. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44107.     

关于逻辑函数化简方法的研究

变量个数大于6的逻辑函数可以称为高变量逻辑函数.逻辑函数的化简方法有公式法和图形法两种.一般认为,对于高变量逻辑函数的化简,图形法没有实用价值.本文观点与此不同,认为图形法对于高变量逻辑函数的化简仍然具有实用价值,同时提出了用图形法化简高变量逻辑函数的具体方法.提出并证明了一个定理,该定理揭示了将高变量逻辑函数转化为低变量逻辑函数并用小卡诺图来化简的一般意义和实用意义.通过本文,进一步丰富和完善了数字系统的设计工具--布尔代数的理论和实践.     

一个宽带无线IP网络与Internet网络的互连

当前，在Internet中实现移动终端的无缝接入巴成为Internet的研究热点之一．本文简要介绍了一个基于WCDMA技术的宽带无线IP网络及其拓扑结构；增加和定义了一个无线IP子层协议及功能；详细描述了无线IP子层的设计、无线TCP连接和自适应无线拥塞控制算法的实现．实验结果表明任意一个无线终端都能够利用Ping、IE、FTP、Emai1、Telnet等软件稳定有效地访问Internet．     

Cr2O3对高放核废料磷酸盐玻璃固化体的影响

在含高放核废料的玻璃固化体中添加了不同含量的Cr2O3，以考察其对玻璃固化体的结构和性质的影响．对添加Cr2O3的玻璃固化体进行了各种方法(溶出速率法，蒸汽水化侵蚀和试样坚固性法)的化学稳定性的测试．测试结果表明，Cr2O3的引入不会对玻璃固化体的化学稳定性产生不良的影响．与此相反，Cr2O3能抑制各种离子自玻璃固化体中沥析出来，改善玻璃固化体的化学耐蚀性．XRD内标法测定，Cr2O3在铁磷酸盐玻璃中的溶解度可达4．1％，是其在硼硅酸盐玻璃的3倍．FTIR和DTA的结果表明，不同含量的Cr2O3的引入，不会对玻璃固化体的网络结构造成显著的变化．Mossbauer谱表明，Fe^2 ／Fe^3 的比值随着Cr2O3的含量的增加而增大，说明Cr离子和Fe离子在玻璃熔制过程中发生氧化还原反应，形成的Cr^ 6有利于提高玻璃固化体的化学耐蚀性．     

热-机械再生乳胶制品及其再生胶性能研究

采用转矩流变仪再生废乳胶制品,考察了再生温度对乳胶制品再生胶性能的影响。结果表明,随着再生温度的升高,乳胶制品再生胶的溶胶含量上升15.5%,交联密度和门尼粘度分别下降16.7%和6.3%。再生温度为145℃时制备的乳胶制品再生胶综合性能最佳,硫化胶的拉伸强度可达到15.5 MPa。衰减全反射红外光谱分析结果表明胶粉再生前后主链没有发生大的变化,-CH2-的弯曲振动明显增强可能是交联网络结构中的部分C-S键断裂导致的。微观形貌分析表明再生过程中原料的交联网络结构受到一定程度的破坏。     

SMART Design of a Bulk‐Capped Supramolecular Segment for the Assembly into Organic Interdigital Lipid Bilayer‐Like (ILB) Nanosheets

Rational molecular design for the organic nanocrystal morphology still remains a challenge due to the structural diversity and complicated weak intermolecular interactions. In this work, a typical attractor–repulsor molecule N,N‐diphenyl‐4‐(9‐phenyl‐fluoren‐9‐yl) phenylamine (TPA‐PF) is designed to explore a general assembly strategy for 2D nanocrystals. Via an interdigital lipid bilayer‐like (ILB) molecular packing mode, large‐sized lamellar 2D nanosheets are obtained with a length:width:thickness ratio as ≈2500:1000:1. The d‐spacing of the largest (001) plane is 1.32 nm, which equals to the thickness of a single interdigital stacking layer. The synergetic effect of the attractive supramolecular segment (TPA) and the repulsive bulky group (PF) is supposed to be the critical factor for the ILB packing that leads to the 2D structures. The attractor–repulsor molecule design is expected to be an effective strategy for the growth of 2D nanocrystals based on small organic molecules.     

In Situ Self‐Assembling Micellar Depots that Can Actively Trap and Passively Release NO with Long‐Lasting Activity to Reverse Osteoporosis

Treatment with exogenous nitric oxide (NO) donors is regarded as being effective against osteoporosis. However, NO has a short half‐life, limiting its clinical usefulness. To overcome this limitation, an injectable microparticle (MP) system is developed that consists of phase‐change materials capric acid (CA) and octadecane, and encapsulates a NO donor. The therapeutic efficacy of the MPs is evaluated in ovariectomized (OVX) rats with osteoporosis. Upon subcutaneous administration, the MPs undergo a phase transition, leaching out the NO donor and generating NO bubbles that are instantly covered by a layer of tightly packed CA surfactant molecules, forming micellar depots. The in situ self‐assembling micellar depots can actively protect the NO bubbles, prolonging their half‐life, while the entrapped NO may passively diffuse through the micellar depots over time, performing a long‐lasting therapeutic function, reversing the OVX‐induced osteoporosis. It is possible to use the concept of in situ self‐assembling micellar depots developed herein to expand the therapeutic effect of NO in its diverse range of clinical applications.     

玻璃熔窑池壁侵蚀机理的研究(一)

运用X射线荧光光谱分析、扫描电镜分析(SEM)对池壁各取样点处侵蚀前后的耐火材料试样进行化学组分分析和显微结构观察,研究玻璃窑池壁的侵蚀机理以及各特征点处的差异.