Analysis of the Sliding Window Powering Algorithm

We analyze precisely the parameters entering the sliding window powering method, and apply this to the case of an elliptic curve over a large finite prime field.     

偏心介质球加载球形腔的解析分析

本文首次对偏心介质球加载理想导体球形谐振腔的谐振模式进行了精确分析，所采用的多极多谐展开注在引入球谐矢量波函数加法定理之后是严格的。讨论了ＴＥ，ＴＭ和混合模式谐振波数随加载介质球电参数，半径和偏心距变化的规律，并给出了部分模式的场分布图，经验证，本文的分析方法和结果是精确的。     

“与密钥模2~n加运算”的差分性质研究

“与密钥K模2n加”－Y=X+Kmod2ⁿ是密码算法中一个常用的基本编码环节,在SAFER++,RC6 Phelix等算法中有广泛的应用。该文对Y=X+Kmod2ⁿ进行了差分分析,首次给出了当差分转移概率取最大值1,次大值1-1/2^n-2,次小值1/2^n-2以及1/2时,输入差,输出差及密钥的结构特点和计数公式。     

Problems and solutions from the fourth International Students’ Olympiad in Cryptography (NSUCRYPTO)

Mathematical problems and their solutions from the fourth International Students’ Olympiad in cryptography (NSUCRYPTO-2017) are presented. We consider problems related to attacks on ciphers and hash functions, cryptographic Boolean functions, linear branch numbers, addition chains, and error correction codes, among others. We discuss several open problems involving the algebraic structures of cryptographic functions, useful proof-of-work algorithms, the Boolean hidden shift problem, and quantum computing.     

向量加法系统验证问题研究综述

Petri网是形式化验证领域最重要的模型之一,具有重要的理论和应用价值.从验证算法分析的角度Petri网可以被等价地抽象为"向量加法系统".在对向量加法模型的研究中人们又发展了一些重要的扩展模型.本文对近些年来国内外学者在向量加法系统验证领域取得的成果进行了系统总结.首先,给出了向量加法系统及几个关键验证问题的形式化定义,并重点总结了一般向量加法系统模型上可达性问题的最新研究进展和关键技术;接着,总结了当限定模型的维度为固定值时相关研究进展,重点给出了2维情况的核心定理;随后,介绍了几个重要扩展模型,并总结了这些模型上验证问题研究的最新进展.在每一部分都对未来研究方向及可能面临的挑战进行了展望.     

支链羟基官能化SBS的制备及在改性沥青中的应用研究

以市售聚苯乙烯-聚丁二烯-聚苯乙烯嵌段共聚物(SBS)为原料,巯基乙醇(MCH)为改性剂,偶氮二异丁腈(AIBN)为引发剂,利用巯基-烯加成接枝反应制备出支链官能化羟基SBS(SBS-g-OH)。通过傅里叶红外光谱(FT-IR)、核磁共振氢谱(1H NMR)、热重分析仪(TGA)的表征验证了接枝反应的可靠性,考察了反应时间、温度和改性剂用量对接枝官能度的影响,以及官能度对SBS-g-OH分子量及PB段1,2-和1,4-结构C=C双键结构的影响。最终考察了不同官能度的SBS-g-OH在沥青中的分散性及对改性沥青热存储稳定性的影响,当官能度为24.07 mol%时,羟基主要接枝在SBS的PB段1,2-C=C双键上,将改性沥青离析实验中的上、下段试样软化点差异由25.1 oC降低至14.7 oC,使离析程度最小,改性沥青的热储存稳定得到明显提高。     

提高商品混凝土抗折强度的探讨

随着商品混凝土在城市道路建设方面的大量应用,如何进一步提高道路混凝土的抗折强度成为各混凝土搅拌站及施工单位关注的热点。本文分别探讨了混凝土坍落度、粗集料粒径与级配、掺和料品种与掺量等因素对C35、C50强度等级的商品混凝土的抗折强度的影响。研究结果表明,通过对原材料的选择与配合比的调整可以经济有效地提高不同强度等级商品混凝土的抗折强度。     

Use of binary and ternary blends in high strength concrete

Combinations of cement additions may provide more benefits for concrete than a single one. In this study, 80 high strength concretes containing several types and amounts of additions were produced. In the first stage, silica fume contents in binary blends that give the highest strengths were determined for different binder contents. In the second stage, a third binder (Class F or Class C fly ash or ground granulated blast furnace slag) was introduced to the concretes already containing Portland cement and silica fume in the amounts found in the first stage. Results indicated that ternary blends almost always made it possible to obtain higher strengths than Portland cement + silica fume binary mixtures provided that the replacement level by the additions was chosen properly. Moreover, the performance of slag in the ternary blends was better than Class F fly ash but worse than Class C fly ash.     

某幼儿园加层的设计与施工

本文着重介绍某幼儿园加层的设计与施工,采用锚杆静压桩加固基础,采用包钢法加固钢筋混凝土柱及粘贴钢片加固主梁的加固设计与施工等方面的经验和教训,以供同行日后加层类似工程时参考。     

After a Decade of Development: A Profile of Municipal Drinking Water Plants Utilizing a Sidestream Injection Process

The technology of rapid ozone mass transfer followed by degasification, the GDT? Process, was first introduced in 1995 Mazzei, A.L., Meyer, R. and Bollyky, L.J. . Proceedings International Ozone Association Pan American Group Conference. “Mass Transfer of High Concentration Ozone with High Efficiency Injectors and Degassing Separators”, November, Cambridge, MA [Google Scholar] by Mazzei et al. At the time of introduction, municipal ozone installations utilized a low concentration, air-fed ozone gas as a disinfectant in atmospheric contact basins fitted with fine bubble diffusers (FBD). Over the past decade, air- fed ozone has given way to highly concentrated, oxygen-fed ozone. The change to concentrated oxygen feed gas has increased concerns about the corrosive effects of high finished water dissolved oxygen (DO). Water treatment plants using oxygen fed ozone have reported finished water DO levels in excess of 20 mg/L, with some plants resorting to air sparging at the back end of the contact basin to restore finished water to atmospheric gas levels.

However, the evolution to oxygen feed gas has also produced significant cost benefits. Operating an ozone generator on oxygen increases its ozone production; reducing the size and capital cost of the generator needed to meet ozone output requirements. The use of a concentrated gas stream has also led to the development of side stream injection systems, which move the gas mixing out of the atmospheric basin and into the upstream pipeline (Neemann, 2002 Neemann, J. . The Use of Injectors and Nozzles for Sidestream Ozone Addition. Proceedings AWWA Water Quality Technology Conference.  [Google Scholar]), resulting in a more compact contact basin design. Municipal water plants not having a CT requirement have streamlined one step further, by eliminating the ozone contact basin in favor of a sidestream injection Process. This paper reviews the technology of the GDT? sidestream injection process and introduces 2 municipal water treatments plant (WTP) installations utilizing this process to remediate taste and odor compounds and as a method to reduce finished water dissolved oxygen concentrations.