食品辐照保鲜研究综合报告

食品辐照保鲜于五十年代开始研究,七十年代开始推广应用,目前正在迅速发展形成一个新技术新产业。1950年,美国原子能委员会开始研究这项新技术。1958年,苏联经研究首先批准了辐照保鲜的马铃薯投入市场。同年,在我国北京和上海地区开始了辐照保鲜技术的研究。1964年,联合国粮农组织(PAO)、国际原子能机构(IAEA)和世界卫生组织(WHO)组成联合专家委员会,开始制定国际辐照食品卫生标准。目前已有60多个国家从事这个新技术的研究和推广应用,并已形成了一定规模的中试生产。全世界已建成50万居里以上的工业性钴源近百座,23个国家批准了45种食品投入商业性生产。辐照食品保鲜、辐照医疗器械和医疗用品消毒、辐照商品防霉和防蛀、辐照高分子材料改性等所形成的辐照工业产值每年已达百多亿美元。     

草莓辐照保鲜工艺研究

本文研究了草莓辐照保鲜工艺。结果表明,封口工艺或它同一定剂量下辐射处理工艺的复合,没有实用价值。它唯有同冷藏工艺复合,方可促进保鲜期的延长。一定剂量下辐射处理工艺能为草莓贮藏提供较理想的初始状态,但同时促使高速率劣变。把辐射处理、冷箱冷藏和封口三种工艺组合起来,能够产生双重协同效应,使草莓保鲜效果达到最佳值。     

辐射技术在食品加工中的应用

综述了食品辐射加工的原理及其作用效果，以及该技术在欧美的应用现状及存在的发展障碍。     

即食菜肴辐照保鲜工艺研究

本工作对炒、蒸、烧烤、油炸、卤制品等即食菜肴进行了系统的辐照保鲜研究。结果表明,适宜辐照的菜肴品种为：雪里红腌菜肉丝、蒸牛肉、扣肉、臭面筋蒸腊鱼、烤牛肉、金童子微辣牛肉、酥皮鸭、麻辣瓦块鱼、肘花、牛肉方腿、蟠龙菜、梅香排骨、五香牛肉、波兰烤肠、台式香肠、熏烤火腿、香菇火腿、三文治火腿。辐照4-8kGy,即食食品的色香味形不变,感官品质好,微生物指标和理化指标符合国家卫生标准,保质期（0-5℃）60d。     

辐照前后苹果中微量元素的ICP-AES法分析

辐照食品保鲜法较之传统的脱水、冷冻、化学处理、罐装、腌渍等保鲜法有许多优点,具有较大的经济效益,已越来越引起人们的兴趣。各国为了确认辐照食品的卫生安全性,对其感生放射性、毒性、致癌和遗传效应以及营养成份和微生物等进行了深入的研究,证实经适宜剂量照射的食品既能保鲜又是安全的。对于辐照食品中的微量元素分析,尚未见到报道。本工作采用ICP-AES法,使用Apple-Ⅱ微机控制的ICAP-9000型直读等离子体光谱仪,测定辐照前后苹果中的微量元素含量。     

137Cs辐照和MAP综合处理对猪肉中沙门氏菌的影响

进行了＾１３７Ｃｓ辐照和ＭＡＰ综合处理对沙门氏菌在灭菌猪肉中致死和残存菌生长状况的研究。研究采用反应面设计,并由得到的数据推算回归方程。结果表明,沙门氏菌的致死明显受辐照剂量的影响,残存菌量的对数与辐照剂量成反比：而ＭＡＰ对辐照沙门氏菌的致死无明显影响。５种不同ＣＯ２体积分数对沙门氏菌辐照后的残存菌生长也无明显影响。辐照和ＭＡＰ综合处理并不比单纯辐照能更有效地控制沙门氏菌的致死和残存菌的生长。与空     

电子束辐照对进口葡萄色泽及保鲜效果的影响

以美国进口葡萄（无核红提）为试材,用剂量为0、0．56、1．11和2．10kGy的电子束辐照后分别于室温（13—17℃）下贮藏7d,低温（4℃±1℃）下贮藏15d。采用单-pH法和色度空间法测定果皮花青素含量和色差变化,用硬度计检测果肉耐压力。结果表明,电子束辐照导致葡萄果皮花青素含量下降,其下降幅度随剂量增加而加大,其中2．10kGy辐照果皮花青素含量显著低于未辐照处理。电子束处理对葡萄果实耐压力产生影响,但与剂量无相关性,其中室温贮藏葡萄的果实耐压力低于相应未辐照处理,低温贮藏15d时,0．56kGy电子束处理的果实耐压力高于相应未辐照处理。电子束处理可减少葡萄微生物数量,且剂量越高,微生物数量越少,腐烂率越低,可保证较好的防腐效果。     

Characteristics of pulsed photo-stimulated luminescence and thermoluminescence for the identification of gamma irradiated poultry eggs

Pulsed photo-stimulated luminescence (PPSL) is a simple screening method that can be employed qualitatively at the spot for the detection of eggs treated with ionizing radiation.Due to the variations in the results during storage,the eggs of ostrich,duck,hen,and quail were irradiated to doses of 0,1,2,and 3 kGy.Most of the samples were incorrectly identified during storage after four months of irradiation.Thermoluminescence (TL) technique was also tried by using egg shells in order to confirm the irradiation treatment in eggs.TL glow curves were recorded between the temperatures 50℃to 400℃at the rate of 5°/s for all the control and irradiated samples.On the basis of integrated areas of first glow curves (TL1),the glow curve ratios (TL1/TL2) and the shapes of maxima of TL1, the irradiation treatment of all the eggs was confirmed.Furthermore,the presence of calcite and aragonite minerals that cause the TL signal in the egg shells were studied using X-ray diffraction spectrometry.     

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.