即时通讯软件的安全性分析

在互联网服务中,即时通讯已成为了最流行的服务模式之一,人们对即时通讯的依赖程度也与日俱增。但是, 频频出现的病毒和黑客攻击使广大用户深受其害,即时通讯的安全问题也日益严峻。为了从根本上解决问题,本文对即时通讯软件的架构和协议进行了深入分析,目的是找出漏洞根源,给开发者和使用者提供防止漏洞的依据。     

Instant Controlled Pressure Drop technology: From a new fundamental approach of instantaneous transitory thermodynamics to large industrial applications on high performance–high controlled quality unit operations

Solvent extraction processes have been largely used in various industries. They recently were improved through new physical concepts such as CO₂ Supercritical Fluid Extraction, Ultrasound assisted process, Microwave-assisted extraction, Instant Controlled Pressure Drop DIC-assisted extraction… Systematically, a pretreatment stage of grinding takes place in order to improve the exchange surface increasing the starting accessibility. Swelling of the material structure implies an increase of the porosity thus leading to higher solvent diffusivity within the solid matrix. A new concept of expanded granule powder has recently been defined using Instant Controlled Pressure Drop DIC technology. Whatever the type of solvent is (even CO₂-SFE), such a swelled structure dramatically intensifies the kinetics through a higher specific exchange surface thanks to the open pores, while improving the solution solvent–solute diffusivity within the solid. Coupled to ultrasound, the internal transfer of solute within the pore solvent can likewise be intensified by replacing molecular diffusion within the pores by an effective convection transfer. In this work, we carried out a first approach of modeling of solvent extraction kinetics of expanded granules involving higher exchange surface and greater internal diffusion process.     

Instant controlled pressure drop extraction of lavandin essential oils: Fundamentals and experimental studies

Détente Instantanée contrôlée (DIC), French for Instant Controlled Pressure Drop, was performed on laboratory apparatus as well as on a pilot plant for proving its feasibility, and identifying the optimized processing conditions and recognizing the energy consumption and the quantity of water used for such an operation. GC–MS and SPME analysis of the extracts and residue material were carried out to assess the extracts and solid residues. The lavandin essential oils obtained by using the new DIC extraction process was studied, modeled and quantitatively and qualitatively compared to the conventional hydrodistillation method. The most important differences between the two essential oils were reflected in the yields, with 4.25 as against 2.3 g EO/100 g of raw matter, and in the extraction time, with 480 s as against some hours for respectively the DIC and the hydrodistillation operations. These differences have been previewed through the fundamental analysis. They can normally explain the great decreasing of energy consumption to be 662 kWh/t of raw material. The amount of water to be added was about 42 kg water/t of raw material.     

基于Android的简易即时通信系统设计与实现

该文介绍了一种基于云技术实现Android设备之间文字、语音即时通信的解决方案。该系统无需搭建服务器,利用免费的公共云存储平台以及推送平台实现主要功能,具有简单易行、稳定可靠、可扩展性强等特点。该系统避开了移动运营商的短信和语音电话平台,为小范围人群通信提供了一种实时、廉价的通信方式。     

顶空/气相色谱-质谱法分析方便面印刷包装材料中挥发性有机物

利用顶空/气相色谱-质谱(HS/GC-MS)联用法对袋装方便面印刷包装材料中7种挥发性有机物(异丙醇、乙酸乙酯、苯、乙酸丁酯、乙苯、间/对二甲苯、邻二甲苯)进行了检测分析.优化的实验参数为:平衡温度80℃,平衡时间40 min.本方法线性关系良好,7种挥发性有机物的相关系数均大于0.9991,检出限为0.004～0.0...     

基于Symbian OS的XMPP协议的实现

即时通信(IM)已成为继电话、传真、E-mail之后一种最重要的沟通与交流方式,特别在移动互联网上的应用占有越来越重要的地位,而XMPP协议是IM的标准协议,把XMPP协议移植到智能手机操作系统中,特别是占有智能手机市场首位的Symbian OS中,并在此协议栈上开发IM应用软件具有广泛的市场意义。本文首先分析了移植开源XMPP协议到Symbian OS的可行性,然后提出了代码移植步骤,最后根据代码移植步骤给出了移植XMPP协议栈的具体实践。     

基于Android平台的一种保护隐私的即时通讯工具的设计与实现

在移动互联网飞速发展的今天,即时通讯工具已经成为人们生活和工作中不可或缺的工具。但是,国内外主流的即时通讯工具依然面临着两大主要问题。一个是基于不同协议的软件的互联互通问题,另一个是日益严峻的即时通讯的安全性与隐私性问题。为了从根本上解决问题,针对即时通讯工具的特点进行了深入分析,最终设计并实现了一款基于安卓平台上更具安全性、更实用、用户体验更好的即时通讯工具SecretChat。本工具采用开放的XMPP通讯协议,并在XMPP上实现OTR安全协议。经过系统测试,系统具备稳定性并且具有良好的互联互通性能和隐私保护功能。     

智能管道发展思路的探讨

介绍了智能管道的背景,解读了智能管道的内涵,提出了发展智能管道的总体思路,特别是对智能管道支持云计算应用的技术进行了描述,最后概要介绍了移动智能管道的实践和探索。     

SIMPLE和XMPP协议在电信运营商即时通信产品中的应用研究

从现行即时通信软件使用的协议、协议的扩展性、网络负荷、用户认证、与电信网络融合等方面进行了比较.为了进一步验证分析的结果,分别采用两种协议开发了即时通信产品.经过测试可以分析得出两种协议都可以实现即时通信功能,但是适用场景不同,电信运营商要根据自身的产品定位进行选择.     

Improving the quality of instant tea with low-grade tea aroma

Refuse tea is industrially identified as broken mixed fannings (BMF). It is a primary raw material for instant tea production. The aroma escape during the process affects the quality of instant tea used for application in the food and beverage industries. Capturing and adding back aroma to the instant tea is commercially important to overcome this drawback. Hence, the study was focused on profiling the aroma of BMF and respective instant tea based on low country (0–300 m MASL) and upcountry (>600 m MASL) elevation categories of Sri Lanka to identify the impact of growing elevation on aroma profiles to explore blending proportions for better aroma profiles. Furthermore, volatiles that escaped with steam during the instant tea production process were condensed, and this aroma extract was added back to the tea concentrate prior to spray drying to produce the aroma blended instant tea sample (ABIT). Solid-phase microextraction followed by gas chromatography–mass spectrometry was used to identify the volatile compounds in the headspace of instant tea, BMF and ABIT samples. BMF samples significantly contained linalool (9.94 ± 2.94 %), cis-linalool oxide (Furanoid) (4.69 ± 1.80 %), geraniol (2.47 ± 1.44 %), and 3-hexen-1-ol (3.46 ± 2.06 %); however, the volatile profile of instant tea samples had high amounts of hydrocarbons (51.60 ± 9.34 %) that did not contribute to creating a pleasant aroma for the product. Hexanal, geraniol, citral, cis-jasmon, α-ionone, nerol and E-2-Z-4-hexadienal are characteristic in upcountry BMF and were absent in the low country tea, indicating a difference in the aroma profiles with elevation. ABIT sample showed that there is a clear improvement in the aroma profile by retaining compounds such as linalool (5.48 %), geraniol (0.95 %), hotrienol (0.92 %), and γ-muurolene (0.22 %), which give a pleasant flowery aroma to the product. This study concluded the possibility to improve the aroma profile of instant tea to give the unique aroma of Ceylon tea as per customer requirements in an economically viable manner and this technology can be applied globally.