Comparison between REA model and thin layer drying model based on strip drying kinetics

为了获得最适用于烟草干燥的动力学模型,达到设计、优化和控制烟草干燥过程的目的,采用湿度发生器联用热重技术(TGA)研究了65 ℃ &RH; 15%, 75 ℃ & RH 10%和85℃& RH 5%条件下片烟的干燥动力学行为,并利用REA (Reaction engineering; approach)以及8种经验或半经验的薄层干燥模型分别对不同温湿度条件下的片烟干燥行为进行模拟。结果表明:①干燥温度越高,相对湿度越小时,片烟; 的干燥速率越快,平衡含水率越低;②REA模型预测的片烟干燥动力学曲线与实验曲线能够很好地吻合,尤其是在含水率由20%降至12%阶段;8种薄层干燥; 模型中Two; term模型拟合出的R~2值最大,均方根误差(RMSE)最小,是描述片烟干燥行为较合适的模型;③薄层干燥模型仅仅是获得特定温湿度条件下相对应的动; 力学参数,而REA模型是将温度和湿度作为变量引入模型中,模型中的动力学参数可以描述任意温湿度条件下的片烟干燥动力学行为;④REA模型构造简单,预; 测准确快速,较Two term模型更具有普适性、实用性。In order to select a kinetic model best fit for the design, optimization; and control of tobacco drying process, the drying kinetic behavior of; tobacco strips under the conditions of 65 ℃ & RH 15%, 75 ℃ & RH10%, 85 ℃; & RH 5% was investigated with a humidifier combined with TGA; (Thermogravimetric analyzer). The drying behavior of tobacco strips was; simulated by REA (Reaction engineering approach) model and eight; selected thin layer drying models (semi-empirical or empirical). The; results showed that: 1) With the rise of temperature and decrease of; humidity, the drying rate of strips raised and the equilibrium moisture; content of strips lowered. 2) The drying kinetic curves predicted by REA; model well agreed with experimental curves, especially at the stage when; the moisture content decreased from 20% to 12%. Among eight thin layer; drying models, Two term model was the best for predicting the drying; behavior of strips with the highest R~2 (determination coefficient) and; the lowest RMSE (root mean square error). 3) Thin layer drying model; reflected only the kinetic parameters corresponding to specified drying; conditions, while in the REA model the temperature and humidity served; as variables, it enabled the kinetic parameters in REA model to describe; the drying kinetic behavior at any drying condition. 4) REA model was; simple in structure, fast and accurate in prediction, more universal and; practical than Two term model.福建中烟工业有限公司科技项

Corrosion Characteristics of Electrodeposited Ni Mo P Alloy Immersed in NaCl Solution

用失重法、阳极极化曲线、Ｘ光电子能谱（ＸＰＳ）以及俄歇电子能谱（ＡＥＳ）研究了电沉积ＮｉＭｏＰ合金镀层在５％ＮａＣｌ溶液中的腐蚀特性．非晶态ＮｉＭｏＰ合金镀层比晶态ＮｉＭｏＰ合金镀层有较低的腐蚀速度．阳极极化曲线表明，ＮｉＭｏＰ合金镀层中，镍的摩尔分数为０．７１９～０．８６８时，随镀层中磷含量的增加，腐蚀电位正移；而活化区的峰电流随镀层中钼含量的增加而增加．磷含量对活化区的峰电流以及钼含量对腐蚀电位的影响均很小．ＸＰＳ和ＡＥＳ分析指出，经５％ＮａＣｌ溶液中浸渍后，ＮｉＭｏＰ合金镀层表面形成厚度约为５０ｎｍ的氧化膜．这层氧化膜主要由Ｎｉ２Ｏ３，ＭｏＯ３和ＰＯ４３－等构成，其在电解质溶液和合金间起着阻挡层的作用．The corrosion characteristics of electrodeposited Ni Mo P alloy immersed in 5wt.% NaCl solution were investigated using immersion, anodic polarization curves, XPS and AES analysis. The corrosion rates of amorphous Ni Mo P alloys are lower than that of crystalline Ni Mo P alloys. Anodic polarization curve experiments show that for the electrodeposited Ni Mo P alloys, the nickel mol fraction of which has in between 0.719 and 0.868, the corrosion potential moves to positive with the increase of P content, and the peak current value of active region increase with the increase of Mo content in alloys, though the effects of P content on the peak current of active region and of Mo content on the corrosion potential are insignificant. XPS and AES analyses indicate that after immersion in 5wt.% NaCl solution, an oxidation film of about 50 nm in thickness is formed on the surface of Ni Mo P alloys. This oxidation film is composed of Ni 2O 3,MoO 3 and PO 3- 4, and acts as a barrier between the alloy and the electrolyte.作者联系地址：湖南师范大学化学系,天津大学应用化学系Author's Address: Department of Chemistry, Hunan Normal University, Changsha, Hunan, 410006 Yao Suwei Guo Hetong Department of Applied Chemistry, Tiangjin University, Tianjin, 30007

36单元塑料闪烁体陈列探测器制作与调试

本文描述了一个能在中解（10－100Mev/u）重离子核反应测量中鉴别轻粒子，测量粒子多重性，并能给出轻粒子能量和位置信息的大立体角（θ: 5°-20°φ: 0°-360°）的36单元塑料闪烁体陈列探测器的制作与调试，初步调试结果表明该探测器对轻粒子（p、α等）有较好的分辨。同时对国际上几种规模较大的先进的多单元大立体角粒子探测系统作了比较全面的介

OPGW应用领域技术发展趋势

文章介绍了近年来的部分新技术在OPGW（光纤复合架空地线）中的应用,包括光纤传感技术在OPGW的温度、应力在线监测方面的应用,OPGW融冰新技术,200μm外径新型光纤在OPGW中的应用,大余长光纤OPGW在OPGW中的应用。并对OPGW光缆应用领域技术的发展趋势进行了预测

视线

厦门大学《凌云报》第一版视线专栏10月17日，动感地带之夜——厦门大学2010年研究生迎新晚会在建南大会堂隆重上演。图为厦门大学模特队的创意时尚彩妆秀，时尚元素与古典韵味碰撞与交融，将“中国风”演绎得淋漓尽致。（夏跃飞/摄） 厦门大学第45届校运动会即将举行。图为新闻传播学院的学子正在演武体育场训练校运会女子接力赛项目。(曾一洺/摄) 图为我校艺术学院雕塑系李冬同学的工艺作品。据介绍，作品的灵感来自老师的作业——以点、线、面构成作业。最终这件用金属物构成的工艺品既展示了金属的质感，又不失灵动的美感。（夏跃飞/摄）厦门大学研究生

Design and Implementation of Time Frequency Differential ofDM Underwater Voice Communication System

时频差分OfdM技术可充分利用时域、频域差分调制抑制时变多径水声信道的影响;同时,系统复杂度低、无需采用信道估计和均衡算法,适于硬件实现.本研究给出了基于浮点型dSP TMS320C6713的时频差分OfdM水声语音通信系统的总体方案、软硬件设计和实现,并对该系统进行了海上实验验证性能,结果表明该系统恢复出的语音质量良好,可以满足水声语音通信的要求.Time-frequency differential orthogonal frequency division multiplexing(ofDM)technology can make full use of time and frequency domain differential modulation to overcome the impact of time-varying underwater acoustic channel,with low implementation complexity as well as no need for channel estimation and equalization algorithm.This paper introduces the overall scheme design,hardware design,and software algorithm of the processing platform of underwater speech communication based on digital signal processing(DSP)TMS320C6713.Sea trial is conducted to test the performance,which shows that the quality of voice communication is satisfactory.The system has the potential to be used in the practical underwater applications to meet the requirements of underwater voice communication.国家自然科学基金(11274259

Underwater Acoustic Spread Communication Scheme by Hybridly Adopting Passive Time Reversal and RAKE Receiving

在多径水声信道条件下,时间反转和rAkE接收机技术是直接序列扩频通信系统利用多径能量提高通信性能的2种常用方法,但在实际环境中信道多径结构、信噪比等因素影响着时间反转技术和rAkE接收机技术的性能.针对这个问题,分析了时间反转技术和rAkE接收机抑制多径干扰的不同机制,并提出一种通过混合使用被动时反与rAkE接收来结合两者优点的扩频水声通信新方案.该方案在不同信道结构及信噪比条件下可优化选择合适的多径抑制手段从而提高系统稳健性.湖试实验表明:在高信噪比下,时间反转可利用高质量的探针信息对多径进行聚焦,在低信噪比下则通过rAkE接收机重组多径能量,从而更好地抑制多径,克服码间干扰,提高通信系统的稳健性.Direct sequence spread spectrum(DSSS)offers an effective way for underwater acoustic(UWA)communication due to its spread spectrum processing gain and its capability to discriminate multipath components.For DSSS underwater acoustic communication systems,the time reversal strategy as well as the RAKE receiver technique is recognized as potential candidates for mitigating the multipath interference.However,performances of time reversal and RAKE receiver is subject to factors such as multipath patterns and SNRs(signal noise ratios).In this paper,based on the theoretical analysis of different multipath mitigation mechanisms of time reversal and RAKE receiver,a novel hybrid multipath mitigation scheme is proposed,switching between the time reversal and the RAKE mode according to the SNR.Finally,experimental results show that time reversal focuses the multipath by using high quality probe under high SNR,and under low SNR,RAKE receiver restructures the multipath.In these ways,the proposed scheme suppresses the multipath better and eliminates the code interference.Experimental results are provided to validate the effectiveness of the proposed method.国家自然科学基金(11274259); 教育部高等学校博士点专项科研基金(20120121110030

In Situ Surface Raman Spectroscopy Study of Electrodeposition Mechanism of Ni-P Alloys

Codeposition mechanism of phosphorus with nickel on an Ni Ag alloy electrode has been investigated by means of in situ surface enhanced Raman spectroscopy(SERS) and electrochemical method to obtain new information about the phosphorus incorporation mechanism during electrodeposition of Ni P alloys.The intermediate,Ni(PH3)n,in the electrodeposition of Ni P alloy was detected with in situ surface Raman spectroscopy for the first time. The experimental results showed that in the solution without NiSO4,hypophosphite was reduced only to Ni phosphine compound,while in the case where NiSO4 coexisted in the solution,the Ni phosphine compound,as an intermediate,was oxidized by Ni2＋to elemental phosphorus in alloys with nickel acting as the catalyst.国家自然科学基金!(59605006

The Ancient Greek Social Economy and the Ancient Olympic Games

古代奥林匹克运动会是世界古代体育文化中一颗璀璨明珠。探讨古希腊奥运会繁荣的原因是近年来世界体育史研究的热点之一。本文试图从古希腊的社会经济状况这一角度进行分析 ,为研究古奥运会提供参考依据。The ancient Olympic games are the “bright pearls”of the world ancient physical culture .Recently the reasons for the study of ancient Greek Olympic games prosperity is that it becomes one of the heat tonics in world physical history .This article attempts to analyze the Prosperity of the ancient Greek Olympic games from the point of ancient Greek social economy so as to provide references to the academic research in this field