Reversible watermarking in JPEG images based on modified RZL codes and histogram shift

Reversible watermarking has extensive applications in fields such as medical data management and forensic enforcement. In this article, we propose a modified reverse zero-run length (RZL) coding method for reversible watermarking, which introduces fewer modifications to cover than previous ones under the same embedding rate. By combining the coding method with histogram shift and quantization table modification strategy, we propose a novel reversible data hiding algorithm for JPEG images. Compared with previous art, when embedding the same payload, our method has an improvement of at least 2 dB in stego image’s quality, which proves the effectiveness and advantage of our algorithm.     

激波后沉积粉尘的燃烧特征

激波掠过可燃沉积粉尘后将使粉尘颗粒上扬、点火与燃烧。该文给出了描述该现象的理论模型，并对此进行了数值模拟。结果表明，激波马赫数越大，气相中氧气含量越高，颗粒初始直径越小，则颗粒的点火延迟时间越小，颗粒温度及化学反应速率上升越快，颗粒的燃烧时间愈短。     

Synthesis of well-defined functional crystals by high temperature gas-phase reactions

Over the past decades, there have been many synthesis methods on producing well-defined crystals, due to their enormous application potentials in industrial field. Among them, high temperature gas-phase reactions （HTGR） approach may be one of the most promising processes for fabrication of well-defined crystals with controllable structure, size, shape, and composition. This review is focused on the recent progresses in synthesizing well-defined crystalline TiO2 dominated with, respectively, {001 } facets and { 105 } facets, one-dimensional ZnO and SnO2 nanorods/nanowires, MoS2 nanosheets as well as GaP, InP, and GaAs nanowires via HTGR approach. Although these research works were currently carried out on experimental scale, it is worth to note that the industrial importance of this HTGR approach for design and fabri- cation of well-defined crystals in the future owing to its advantages of continuous and scalable production with controlled dimensions and low cost.     

鼻咽癌调强适形放疗与常规放疗比较分析

目的分析比较鼻咽癌患者调强放疗与常规放疗的优势.方法 70例鼻咽癌患者随机分为两组,调强放疗组(IMRT)35例,常规放疗组(CRT)35例.IMRT组靶区为鼻咽肿瘤、咽旁间隙和颈部淋巴区,放射剂量DT 70 Gy;CRT组采用面颈联合野加颈部切线野照射,原发灶根治量为DT 70~72 Gy,颈部预防治疗量DT 50 Gy.结果 IMRT组和CRT组总有效率分别为94.3%和85.7%,口腔黏膜反应Ⅳ级两组分别为0例和2例,两组比较差异具有统计学意义(P0.05).结论鼻咽癌调强放疗比常规放疗有明显优势.     

基于自由基链式反应改进干法烟气脱硫技术的方法

为了提高干法烟气脱硫反应的速率并改良脱硫产物,提出了一种基于自由基链式反应同步氧化烟气中NO和SO2的方法。对该方法的机理进行了分析,提出了利用添加剂引发烟气中链式反应的设想。分别选用双氧水、碳氢化合物、硝酸作为添加剂开展了实验研究。实验结果表明:利用链式反应同步氧化烟气中的NO和SO2是可行的。添加剂的选取很关键:双氧水和碳氢化合物由于自身消耗OH自由基,不能维持链式反应的进行;硝酸热解可有效地提供OH自由基,实现NO和SO2的同步氧化。优化反应条件有助于提高NO和SO2的氧化率。     

Luminescence research and its relation to ultraweak cell radiation

Summary The fundamental laws of photochemistry and the essential results of experimental research on ultraweak cell radiation are presented. By comparing all the facts it can be concluded that the phenomena discussed may arise from a variety of possible reactions and sources. Recombination reactions of certain radicals actually do release sufficient energy to generate UV-photons of the intensity under consideration. On the other hand, stimulated emission cannot be excluded in view of the distinct deviation of the radiation field from thermal equilibrium. There exist, however, various other candidates, such as direct emitters like flavins, indoles, porphyrins, carbonyl derivatives and aromatic compounds, and molecular oxygen and its various species, as well as collective molecular interactions, e.g. dimole or exciplex transitions, triplet-triplet annihilation, collective hydrolysis, electric field effects in membranes, etc.Careful biochemical and biophysical experiments are still necessary to find answers to all the questions that remain; not only individual problems have to be solved, but it is important to keep in mind the interrelationships between certain reactions.     

化学反应中的自由边界问题的计算

本文利用MEYER的不变嵌入法,计算边界类似于Stefan问题的化学反应中自由边界问题,并进一步讨论它的收敛性,以及改进MEYER的不变嵌入法,使改进后的计算精度更好。     

高温应用形状记忆合金时效初探(英文)

形状记忆合金的应用开发异常活跃。然而,对于环境温度超过100℃的所谓高温应用,却涉及较少。本实验研制了成分为Cu-13Al-2.81Ni(wt%)的铸造合金,其转变温度均大于100℃。淬火后的试样在180℃停放30天,相应进行电阻温度回线测室、X衍射实验及透射电镜观察。实验结果表明:合金于180℃时效,起初随着时效时间的延长,马氏体转变温度提高,而转变量基本不变;25天后,转变量急剧减少,转变温度下降。时效前后,X衍射图谱无明显变化。透射电镜观察到时效30天的样品内部出现大量的块状共格过渡相,该共格过渡相与马氏体结构一致、成分不同,阻碍马氏体的可逆转变。     

煤矿中使用高分子材料给安全工作带来的隐患

本文通过使用高分子材料的概况以及高分子材料的应用给煤矿安全工作带来的隐患,从理论上重点阐述了高分子材料产生静电和在燃烧时产生有害气体所造成的危害     

β-乙酰氨基酮类化合物的合成

报道了磺氨酸催化多组分一锅法合成β-乙酰氨基酮的方法.该方法具有产率高、反应条件温和、反应时间短、催化剂可以重复利用等优点。