A novel Variable-Length Code for robust video coding

A novel Variable-Length Code （VLC）, called Alternate VLC （AVLC）, is proposed in this letter, which employs two types of VLC to encode source symbols alternately. Its advantage is that it can not only stop the symbol error propagation effect, but also correct symbol insertion errors and avoid symbol deletion errors, so the original sequence number of symbols can be kept correctly, which is very important in video communication.     

ZD2070新型水平定向钻机

水平定向钻机是应用最广的一种非开挖地下管线施工设备。本文详细介绍了ZD2070新型水平定向钻机的结构特点、工作原理、主要技术参数以及所采用的若干新技术。     

监控系统协议仿真研究

通过分析监控系统的通讯协议,提出了利用计算机进行协议仿真,以串行接口为例给出一个通用的协议仿真软件,并介绍了若干个应用实例.     

Runx1 Messenger RNA Delivered by Polyplex Nanomicelles Alleviate Spinal Disc Hydration Loss in a Rat Disc Degeneration Model

Vertebral disc degenerative disease (DDD) affects millions of people worldwide and is a critical factor leading to low back and neck pain and consequent disability. Currently, no strategy has addressed curing DDD from fundamental aspects, because the pathological mechanism leading to DDD is still controversial. One possible mechanism points to the homeostatic status of extracellular matrix (ECM) anabolism, and catabolism in the disc may play a vital role in the disease’s progression. If the damaged disc receives an abundant amount of cartilage, anabolic factors may stimulate the residual cells in the damaged disc to secrete the ECM and mitigate the degeneration process. To examine this hypothesis, a cartilage anabolic factor, Runx1, was expressed by mRNA through a sophisticated polyamine-based PEG-polyplex nanomicelle delivery system in the damaged disc in a rat model. The mRNA medicine and polyamine carrier have favorable safety characteristics and biocompatibility for regenerative medicine. The endocytosis of mRNA-loaded polyplex nanomicelles in vitro, mRNA delivery efficacy, hydration content, disc shrinkage, and ECM in the disc in vivo were also examined. The data revealed that the mRNA-loaded polyplex nanomicelle was promptly engulfed by cellular late endosome, then spread into the cytosol homogeneously at a rate of less than 20 min post-administration of the mRNA medicine. The mRNA expression persisted for at least 6-days post-injection in vivo. Furthermore, the Runx1 mRNA delivered by polyplex nanomicelles increased hydration content by ≈43% in the punctured disc at 4-weeks post-injection (wpi) compared with naked Runx1 mRNA administration. Meanwhile, the disc space and ECM production were also significantly ameliorated in the polyplex nanomicelle group. This study demonstrated that anabolic factor administration by polyplex nanomicelle-protected mRNA medicine, such as Runx1, plays a key role in alleviating the progress of DDD, which is an imbalance scenario of disc metabolism. This platform could be further developed as a promising strategy applied to regenerative medicine.     

Crosslinking-property relationships in PMR polyimide composites. Part I

This study examines for the first time how matrix crosslinking affects the composite physical and mechanical properties of a graphite fiber reinforced PMR polyimide composite during long-term isothermal aging. Unidirectional composite specimens of Celion 6000/PMR-P1 were isothermally exposed at 288°C in air for various time periods up to 5000 h. The matrix crosslink densities were estimated from the kinetic theory of rubber elasticity and shifts in the glass transition temperatures (T_gs). The T_g, coefficient of thermal expansion, density, weight loss, moisture absorption, and elevated temperature flexural and interlaminar shear properties were also determined. Several linear relationships were found between the matrix crosslink density and composite physical and mechanical properties. The T_g, initial weight loss and density, and elevated temperature interlaminar shear strength increase with an increase in crosslink density. Conversely, the initial moisture absorption and coefficient of thermal expansion decrease with increasing crosslink density. As expected, the elevated temperature flexural strength and modulus show no direct correlations with crosslink density. Further, after achieving the highest matrix crosslink density, several of the composite properties begin to decrease rapidly. These findings suggest that time-temperature dependent nature of attaining the maximum matrix crosslinking is closely linked to the onset of the composite property degradation. Though much more work is needed, a fundamental understanding of the relationships between matrix crosslinking and composite physical and mechanical property can provide a scientific basis for the prediction of the extent of composite service life not only for PMR polyimides but also for other thermosetting matrix resins, such as epoxies and bismaleimides.     

基于核壳型量子点的生物传感器在真菌毒素检测中的应用进展

真菌毒素是真菌产生的有毒次生代谢物,其广泛存在于被污染的食物中,其中黄曲霉毒素已被认定为天然存在的剧毒致癌物。鉴于真菌毒素污染给人类健康与安全带来的风险与危害,发展低成本、快速、高效的检测方法以确保食品安全,具有重要的现实意义。已有大量研究者构建了基于单一量子点或其他荧光材料为荧光探针的生物传感器用于检测真菌毒素,并且从材料、检测方法和生物传感器等角度进行了详细的检测。然而,目前并没有系统地阐述核壳量子点构建的生物传感器在真菌毒素中的应用报道,因此,本文主要从基于核壳量子点构建的免疫电化学发光传感器、适配体免疫电化学发光传感器、免疫荧光传感器、适配体荧光传感器和试纸条传感器在真菌毒素中的应用进展进行阐述,首次系统地阐述了核壳型量子点生物传感器在真菌毒素分析检测中的研究进展,以期为同类研究提供一定的理论依据。     

中医舌诊八纲辨证神经网络知识库构建

根据中医诊断推理对知识的不确定性、不完全性和逻辑推理的模糊性及“软计算”技术的特点出发,探讨了利用“软计算”的方法构建中医诊断神经网络知识库的基本设想,最后在MATLAB中利用现有结构固定的三种神经网络模型分别粗略地构造了中医“八纲辨证”神经网络,并分析其计算结果。说明采用神经网络技术构建中医诊断知识库是完全可行的。     

采用改进的遗传算法与Mod.UNIFAC基团贡献设计萃取剂

将Mod．UNIFAC基团贡献法与改进的遗传算法相结合,进行萃取精馏萃取剂的分子设计。针对遗传算法搜索效率低和不易得到全局最优解等问题,对遗传算法的编码方案和遗传操作算子中的选择和变异算子进行了改进,有效避免了该方法的自身缺陷。将其应用于乙醇-乙酸乙酯体系,设计得到了三甲苯、丙三醇、氯苯等高效萃取剂,将相对挥发度的预测值与文献值比较,平均偏差小于8%。说明了所采用的方法是准确可靠的。     

视频信息伪装技术综述

介绍了视频信息伪装技术的一般原理,分析了其特点,阐述了所采用的一些主要方法,并对视频信息伪装的攻击手段进行了探讨;最后指出了目前视频信息伪装技术值得进一步研究的问题。