超混沌同步的非线性控制法

用李雅普诺夫函数法与尝试法相结合的方法，构造了１组典型的非线性反馈函数，实现了２个超混沌Ｒｏｓｓｌｅｒ系统的同步。     

复数Lorenz-Haken系统中的超混沌同步及其控制(英文)

以描写失谐单模激光特性的复数Lorenz-Haken系统及其高阶级联系统作为第一个典型例子,首先实现了存在驱动-响应关系类型的超混沌同步,并采用间歇正比于所有系统主变量反馈控制法,实现了超混沌的有效稳定控制。引入的思想方法及概念可以拓广到其他超混沌系统的同步及其控制。指出了混沌同步、超混沌同步及其控制可能的实际应用前景,诸如在激光、等离子体、电子学、密码学、通讯、化学和生物系统等领域中的可能应用潜力。     

混沌系统的滑模变结构观测器同步

将滑模变结构观测器方法用于混沌系统的同步，该方法不需要计算Lyapunov指数。该观测器摒弃了对系统的参数变化适应性不强的传统的利用反馈矩阵进行极点配置的线性反馈，采用了对系统参数摄动鲁棒性更好的变结构控制，其对混沌系统的噪声和参数失配鲁棒性更强。该同步策略被用于熟知的Roessler混沌系统和超混沌Roessler系统，仿真结果证实了该方法的有效性。     

实现混沌同步的非线性变量反馈控制法

应用非线性变量反馈控制法，通过李雅普诺夫函数方法和尝试法，分别构造了一些非线性反馈函数，并用以实现了对Ｒｏｓｓｌｅｒ系统和改进的Ｌｏｒｅｎｚ系统的混沌同步。２种方法起着相互补充的作用。     

26 半导体激光器的混沌反控制与自适应控制

在实际工程中，将一个稳定周期系统驱动到另一个周期态去，必须用足够大的外力才能实现，这就要消耗足够大的能量。混沌反控制则可使系统处于混沌状态，然后获得混沌系统的吸引子具有无穷多的周期态，就可用极小的代价来实现混沌控制，从而达到所需要的稳定周期态。这样，不仅不必回避系统出现的混沌运动，而且在可能条件下人为地将系统首先引导到混沌状态下，然后对这种混沌系统施加某种混沌控制方法，使系统在无穷多规则态的态库中进行自由选择和自由转换，实现目标轨道的灵活选择，这正是混沌控制较其他控制最为显著的优点之一。     

33 外腔反馈式半导体激光器的混沌化与混沌控制

本工作首先通过增加外腔反馈式半导体激光器的激光反馈时间，使系统达到混沌化，然后采用滑模变结构控制方法实现了这种激光器的混沌控制所需的周期态。这种将混沌反控制与混沌控制相结合的方法具有明显的优点，可使系统既能很快地获得稳定的输出激光，又能根据工程需要实现激光输出功率强度的灵活调整，提高了能量转换效率。理论分析和数值计算结果表明，控制结果具有很强的稳定性和鲁棒性，这对改善实际激光系统稳态输出特性，有较好的参考价值。     

用FIR滤波器—PPSV实现混沌和超混沌控制

利用数字ＦＩＲ滤波器和正比于系统变量的脉冲反馈法的级联控制非线性连续系统中的混沌和超混沌。以实数Ｌｏｒｅｎｚ系统和复数洛仑兹－哈肯系统为例进行了数值研究。结果表明：ＦＲＩ－ＰＰＳＶ级联控制法比仅用ＦＩＲ滤波法或ＰＰＳＶ法更能有效地控制非线性连续系统中的混沌和超混沌,且抗噪性能ＰＰＳＶ法有显著提高。     

实现混沌同步的非线性变量反馈控制方法

应用非线性变量反馈控制法，通过李雅普诺夫函数方法和尝试法，分别构造了一些非线性反馈函数，并用以实现了对Ｒｏｓｓｌｅｒ系统和改进的Ｌｏｒｅｎｚ系统混沌同步，２种方法起着相互补充的作用。     

Chua电路混沌系统的同步分析

Chua电路是混沌系统中倍受人关注,具有广阔应用前景的混沌电路,如何同步混沌系统是应用的前提条件,用三种方法分析了Chua电路混沌系统的同步问题,为在电路上实现Chua电路混沌系统的同步提供了理论基础和技术指导。     

基于LabView的Jerk混沌系统的实现

为了克服模拟电路混沌系统实现易受外界条件影响等问题,以Jerk混沌系统为例,论文提出了一种基于LabView的混沌系统的实现方法。同时设计了相应的模拟硬件电路,并分别给出了实验结果。实验结果表明,利用LabView软件产生的实验结果与模拟电路产生的结果一致。证实了基于虚拟仪器技术可为研究非线性系统提供可行的方案。与传统的自治混沌系统相比,此系统具有参数调节方便、易实现、可靠性高,实时性好等优点,这为混沌系统的实现提供了新的思路。     

Preparation of Zn/TiO2 powder and its photocatalytic performance for oxidation of P-nitrophenol

Zn-doped TiO2 catalysts were prepared using a sol-gel method and characterized by XPS,UV-Vis, BET, XRD in this study. Under the irradiation of simulant sunlight, the photocatalytic activity for the degradation of p-nitrophenol was studied too. After irradiation for 2.5 h, the degradation percentage of p-nitrophenol could rise to more than 80 %. The results showed that the spectrum absorption band edge of Zn/TiO2 powder does not broaden obviously comparing with pure TiO2 powder. Zinc exists as Zn （11）. When calcined at 973 K, there is a new phase as ZnTiO3 in Zn/TiO2 catalyst. The order of photocatalytic activity of Zn/TiO2 catalysts calcined at different temperatures for p-nitrophenol is 773 K 〉 673 K 〉 873 K 〉 573 K 〉 973 K and the photocatalytic activity of Zn/TiO2 catalyst calcined at 773 K is better than TiO2 catalysts heated at the same temperature, and outclasses that of commercial TiO2 catalyst. It also showed that the photocatalytic degradation of p-nitrophenol follows first-order kinetics under the irradiation of simulant sunlight.     

Current status of radiation therapy for prostate cancer

Radiotherapy for the treatment of prostate cancer has been extensively explored in the past. Along with the comprehensive understanding of the biology of prostate cancer and rapid advances in terms of technology, the out- come of treatment for the patients with prostate cancer has improved. The authors review radiotherapy as the primary treatment for the disease, with particular emphasis on the technological advances from both the radiobiological and radiophysics aspects. Nonconventional fractionated irradiation like hyper- or hypo-fractionation has been imple- mented in the clinic, the final results still need to be confirmed in the future. Technological advances like IMRT, IGRT, in the last two decades have significantly improved the delivery of external radiotherapy to the prostate. This has re- sulted in an overall increase in the total dose that can be safely delivered to the prostate, which has led to modest im- provements in the biochemical outcome. However, establishing the standard therapy for prostate cancer remains con- troversial. It is hoped that the next decades will bring continued advances in the development of biologicals that will further improve current clinical outcomes.     

The control system for SSRF injection and extraction

This paper introduces the injection and extraction control system design for SSRF,which is a distributed control system aimed at stability and reliability of the pulse power supplies,PPS(Personnel Protection System)and MPS(Machine Protection System).The hardware environment is mainly based on PLC(Programmable Logic Con- troller),and ARM(Advanced RISC Machine)is also applied for studying stability of the power supplies.WinCC and EPICS(Experimental Physics and Industrial Control System)have been selected as the platforms of SCADA(Super- visory Control and Data Acquisition).For unifying the interfacing to the control computer,all front-end equipments are connected via Industrial Ethemet.     

水平管内含空气蒸汽强制对流冷凝换热模型研究

为研究含空气蒸汽在水平管内强制对流冷凝换热特性,基于对传热传质过程的分析,建立了管内为环状流与波状流条件下的流动冷凝换热模型。从潜热、显热和液膜3个环节对整个换热过程进行建模,最终得到计算局部冷凝换热系数的理论关系式。模型预测结果与实验数据的对比表明,二者相对偏差在±20%以内,验证了该换热模型的准确性与适用性。通过进一步的研究发现：从换热管入口至出口,随着冷凝的进行,管内换热主要热阻由液膜热阻向气液界面的凝结热阻转变;主流气体对流换热过程基本可忽略。     

Investigations on landmine detection by BF3 detector

Experiments were carried out to investigate the possible use of neutron backscattering for the detection of polyethylene (PE) sample buried in the soil. In detection of landmine by neutrons, the neutron detector and its shield play an important role. In this paper, the effects of graphite, heavy water, polyethylene and boric acid moderators on the flux of back scattered neutrons were investigated. We have also experimentally verified the effect of BF3 detector shield and obtained good agreement with theory.     

Web Services interface of SSRF archive data analysis system

Accelerator database stores various static parameters and real-time data of accelerator. SSRF (Shanghai Synchrotron Radiation Facility) adopts relational database to save the data. We developed a data retrieval system based on XML Web Services for accessing the archive data. It includes a bottom layer interface and an interface applicable for accelerator physics. Client samples exemplifying how to consume the interface are given. The users can browse, retrieve and plot data by the client samples. Also, we give a method to test its stability. The test result and performance are described.     

Assessment of radioactivity levels in some oil samples from the western desert, Egypt

Distributions of natural gamma-emitting radionuclides were determined in 93 oil samples collected from some petroleum fields in the western desert of Egypt. The radioisotope activities in the area under investigation lay in the range of (21 ± 4) to (38 ± 13) Bq?L-1 for 226Ra, (9 ± 2) to (15 ± 5) Bq?L-1 for 232Th, and (154 ± 28) to (303 ± 54) Bq?L-1 for 40K. The mean values were 27, 12, and 201 Bq?L-1, respectively. Among oils, variations in radionuclide ac- tivities could be on account of differences in TDS, HCO3, and Ba, with high or low pH. In this environment, oil prop- erties differently affected the mobilization of natural radionuclides. The range of 226Ra variation had been compared with available data from other countries. The calculated absorbed dose rate ranged from 22.33 to 32.66 nGy?h-1 in lo- cation (B) and (E) respectively, which was less than the accepted value.     

Preparation and properties of 117m Sn(IV)-TTHMP in in-vitro and in small animals

In this work,TTHMP was synthesized and labelled with 117m Sn.The preparation conditions,stability and lipophilicity of 117m Sn(IV)-TTHMP were investigated.Biodistribution of the complex in rabbits and mice was studied.It was found that the quantity of TTHMP and pH value of the prepararion solution had vital effects on the labeling yield of 117m Sn(IV)-TTHMP.It was also found that 117m Sn(IV)-TTHMP was hydrophilic and stable at room temperature and 37℃ in open air 117m Sn(IV)-TTHMP showed unexpectedly high bone uptake and bone-to-blood ratio in the animals.This made it potentially useful as an reagent for skeletal scintigraphy and radiotherapy of bone tumors.     

The role of AGFA high-energy CR in the calibration and quality control of multileaf collimators （MLC）

Linear accelerators equipped with multileaf collimators （MLC） are becoming more common and are widely used in the intensity-modulated radiotherapy （IMRT）. There is an imperative need to ensure the commissioning specification of the linear accelerators for the sake of quality assurance （QA） and quality control （QC）. This paper is aimed to investigate the role of AGFA high-energy CR （Computed Radiography） in calibrating dynamic multileaf collimators and evaluating the accuracy of the leaf position. The result shows that AGFA high-energy CR can easily and conveniently be used to calibrate MLC and verify its position. Hence, the application of AGFA high-energy CR is proved to be an accurate and time-saving method for routine MLC QC, especially when MLC calibration adjustments are required.     

Gamma radiation levels in the ambient environment of the QNPP Base

Monitoring results of gamma dose rate level in 1992～2004 in the ambient environment of the Qinshan Nuclear Power Plants(QNPP)Base,the northeast of Zhejiang Province,are reported in this paper.It is shown that the gamma dose rate of five monitoring sites of 2.5 km to QNPP Base is 84～113 nGy/h,with an average of 96 nGy/h in the 13 years.The average value is close to the background level of 93 nGy/h prior to operation of the QNPP Base,and is lower than the monitoring result of 101 nGy/h at the reference site in Hangzhou City.Within 50 km from the QNPP Base,the cumulative dose rate of the thermoluminescent dosimeter(TLD)is 90 nGy/h,which is lower than the back- ground level of 111 nGy/h.