人牙釉质中自由基含量与照射剂量的关系

本文用电子自旋共振技术，对２５个成人牙釉质样品中的自由基含量进行了测定，研究了牙釉质中自由基含量与辐射剂的关系。在２５个成人牙样中，１６个男性样品，９个女性样品，年龄范围为１８－４１岁．样品分为５组，用＾６０Ｃｏγ射线照射各组样品，剂量率为０．４８     

几种制剂对辐射所致脂质过氧化作用的影响

本文报道了γ射线照射对小鼠肝、脾、肾中脂质过氧化物（ＬＰ０）含量的影响，以及照后服用知母宁、单宁酸和鲨烯等制剂的抗脂质过氧化作用。制剂均灌胃给药，ＬＰＯ用改良的ＴＢＡ分光光度法测定。结果表明，γ射线整体照射小鼠后７２ｈ，其组织中ＬＰＯ含量增高，在０－４Ｇｙ范围内辐射剂量与ＬＰＯ含量呈线性关系；三种制剂均有降低小鼠肝、脾、肾中ＬＰＯ的作用，其中知母宁（０．３５ｍｇ／ｄ）的抗脂质过氧化作用显著优于单宁酸（１５ｍｇ／ｄ）和鲨烯（０．６ｍｇ／ｇ）。     

双能X线吸收法与近红外法测定脂肪含量的评价

用美国Ｌｕｎａｒ ＤＰＸ－Ｌ骨密度仪和日本ＦＶＴＲＥＸ－１０００型近红外仪对９２例人群进行脂肪含量评价。其中７８例为健康人，男性４３例，女性３５例。测定结果女性平均脂肪含量高于男性，两种方法对全部人群的体脂肪测定结果相关系数ｒ＝０．９２１，本文介绍测定原理并对两种方法的优缺点作了评价。     

陕西省土壤中天然放射性核素含量调查研究

本文报道陕西省土壤中天然放射性核素含量的调查研究结果。基本与环境陆地γ辐射剂量率调查同位布点，全省共采集土壤样品６８７个，其中２５ｋｍ×２５ｋｍ网格点土样３５９个。测量采用放化分析法。调查结果表明，陕西省土壤中天然放射性核素含量按面积和按网格点加权均值分别为：￣（２３８）Ｕ，３４．８和３４．３Ｂｑ·ｋｇ￣（－１）；￣（２２６）Ｒａ，３５．４和３４．８Ｂｑ·ｋｇ￣（－１）；￣（２３２）Ｔｈ，４７．３和４６．７Ｂｑ·ｋｇ￣（－１）；￣（４０）Ｋ，６０６．１和６０４．２Ｂｑ·ｋｇ￣（－１）。     

同位素稀释质谱法测定人尿中微量镍,铜,铅

介绍了采用同位素稀释质谱法测定冻干人尿样品中镍、铜、铅的含量。用天然丰度的镍、铜、铅标准溶液标定浓缩同位素＾６２Ｎｉ，＾６５Ｃｕ，＾２０７＾Ｐｂ溶液的浓度，再用此溶液作稀释剂，用ＩＤＭＳ法测定冻干人尿样品中的镍、铜、铅。实验结果表明；冻干人尿样品中镍、铜、铅的含量（质量分数ω）分别为（０．３０９±０．００４）×１０＾－６，（０．４４２±０．０１３）×１０＾－６，（０．１００±０．００４）×１０＾－     

辐射事故剂量范围照射后塑料假牙材料的顺磁共振特性

用电子顺磁共振（ＥＳＲ）技术对两种常用假牙材料（聚甲基丙烯酸甲酯和拜耳树脂）的剂量学特性研究结果如下：在０～２０Ｇｙ６０Ｃｏγ射线照后，两种材料中均被诱发出新的信号，其ｇ值范围为１．９９４２～２．０１４４。聚甲基丙烯酸甲酯在上述剂量范围内信号强度对照射剂量呈线性响应（ｒ＝０．９７），且信号线宽也随剂量有明显变化。而拜耳树脂在８Ｇｙ以下响应呈正相关，而后响应出现饱和。如照后即刻测量，两种材料可测量下限均不大于２Ｇｙ。在人体体温３７℃下，信号２４ｈ后平均衰减４０％，而后的一周内衰减较慢，约１０％。如照后低温（－２５℃）保存，衰减速度可大大减低，一周内总衰减约２５％－３０％。上述结果表明，如能在事故后及早测量或低温保存样品，两种常用假牙材料都具有充当辐射事故剂量ＥＳＲ检测材料的可能性。其中拜耳假牙难以用于８Ｇｙ以上剂量范围。     

α2M对辐射引起细胞自由基变化的影响

采用６０Ｃｏγ射线照射人皮肤成纤维细胞，并在照射前、后给予不同剂量的甲２巨球蛋白（α２Ｍ），用细胞色素Ｃ法、ＴＢＡ法及邻苯二酚自氧化法分别测定细胞超氧阴离子自由基（Ｏ２）释放、脂质过氧化（ＬＰＯ）水平及超氧化物歧化酶（ＳＯＤ）活力。发现细胞受照后Ｏ２释放和ＬＰＯ水平显著增高（ｐ＜０，０１）；Ｏ２释放与照射剂量呈正相关（ｒ＝０．９６６，Ｐ＜０．０１），ＳＯＤ活力显著下降（Ｐ＜０．０１），且与照射剂量呈负相关（γ＝０．９６６，Ｐ＜０．０１）。照射后给予α２Ｍ能显著抑制Ｏ２释放（Ｐ＜０．０１）、降低ＬＰＯ水平。     

广东大亚湾沿海地区生态环境中^90Sr含量水平调查

本文介绍了１９８８－１９９２年广东大亚湾沿海地区生态环境中￣（９０）Ｓｒ含量水平调查的方法和结果。本次调查分两期进行，在东西宽８０ｋｍ的范围内，共布设了１１５个采样点，采集了２３个品种，３９９个样品。调查结果表明：（１）大气飘尘和雨水的￣（９０）Ｓｒ含量平均值分别低于各自的检测限：４×ｌ０￣（－７）Ｂｑ／ｍ￣３和４×ｌ０￣（－４）Ｂｑ／Ｌ；（２）饮用水和海水中的￣（９０）Ｓｒ含量平均值分别为１．４×ｌ０￣（－３）和２．６×１０￣（－３）Ｂｑ／Ｌ；（３）果园土、菜地土、稻田土和水库底泥中￣（９０）Ｓｒ含量的平均值分别为０．０７７、０．４２、０．７２和０．８４Ｂｑ／ｋｇ（干）；（４）陆上植物中以空心菜中￣（９０）Ｓｒ含量最高，平均值为０．５１６Ｂｑ／ｋｇ（鲜），大米和荔枝中的含量最低，平均值分别为０．０１７和０．０１２Ｎｑ／ｋｇ（鲜）；（５）猪肉、鸡和牛奶中￣（９０）Ｓｒ的含量较低且相接近，平均值为０．０１７Ｂｑ／ｋｇ（鲜）左右。鱼中的含量较高，平均值为０．１５７Ｂｑ／ｋｇ（鲜）。     

陕西省环境天然贯穿辐射水平调查研究

本文报道了陕西省环境天然贯穿辐射水平调查的方法和结果。全省以２５ｋｍ×２５ｋｍ的网格均匀布点，共布设网格点３５９个，另外布设各类加密点４３３个。调查结果表明：（１）陕西省原野γ辐射剂量率按面积、人口和网格点的加权均值分别为６２．０、６３．０和６１．０ｎＧｙ·ｈ￣（－１）；（２）道路γ辐射剂量率按网格点平均为６３．０ｎＧｙ·ｈ￣（－１）；（３）室内γ辐射剂量率按人口和网格点加权均值分别为１００．０和９８．０ｎＧｙ·ｈ￣（－１）；（４）宇宙射线电离成分（不包括中子成分）所致空气吸收剂量率按网格点和人口加权均值，室内分别为３２．０和３１．０ｎＧｙ·ｈ￣（－１），室外分别为３７．０和３６．０ｎＧｙ·ｈ￣（－１）；（５）天然贯穿辐射剂量率，按网格点和人口加权均值，室内分别为１３０．０和１３１．０ｎＧｙ·ｈ￣（－１），室外均为９９．０ｎＧｙ·ｈ￣（－１）；（６）天然γ辐射、宇宙射线和天然贯穿辐射所致居民人均年有效剂量当量分别为０．５５、０．２８和０．８３ｍＳｖ；所致集体年有效剂量当量分别为１．６３、０．８３和２．４６×１０￣４人·Ｓｖ。     

不同制备方法对牙髓样品ESR信号的影响

研究了不同制备方法对牙髓样品电子自旋共振(Electron spin resonance,ESR)信号的影响。无放射线照射史成年人群的臼齿分别用机械方法和机械方法加化学方法进行处理,制备牙髓样品和牙釉质样品。用^60Coγ射线照射样品至不同剂量,测量其ESR信号。比较分析了单位质量样品对单位照射剂量的ESR信号响应灵敏度,以寻求能够有效降低牙髓样品本底信号对其剂量学信号的影响,提高牙髓样品ESR信号灵敏度的样品制备、处理方法。结果表明,不同方法制备的牙髓样品和牙釉质样品,其ESR信号对^60Coγ射线的响应有十分明显的差异。在牙釉质样品缺乏的情况下,利用牙髓样品的ESR信号通过叠加剂量法对受照人员剂量进行重建是可行的。     

狗牙釉质电子自旋共振剂量学的研究

对4组狗牙釉质样品分别进行不同剂量137Csγ射线的照射.使用电子自旋共振(Electron spin resonance,ESR)谱仪测量所有样品照射前的ESR固有信号强度,根据照射不同剂量后的ESR信号强度,研究不同剂量的γ射线照射后狗牙釉质所产生的ESR信号强度的变化.结果表明,137Cs γ射线照射前,狗牙釉质...     

Conversion from Tooth Enamel Dose to Organ Doses for Electron Spin Resonance Dosimetry

Conversion from tooth enamel dose to organ doses was analyzed to establish a method of retrospective individual dose assessment against external photon exposure by electron spin resonance (ESR) dosimetry. Dose to tooth enamel was obtained by Monte Carlo calculations using a modified MIRD-type phantom with a teeth part. The calculated tooth enamel doses were verified by measurements with thermo-luminescence dosimeters inserted in a physical head phantom. Energy and angular dependences of tooth enamel dose were compared with those of other organ doses. Additional Monte Carlo calculations were performed to study the effect of human model on the tooth enamel dose with a voxel-type phantom, which was based on computed tomography images of the physical phantom. The data derived with the modified MIRD-type phantom were applied to convert from tooth enamel dose to organ doses against external photon exposure in a hypothesized field, where scattered radiation was taken into account. The results indicated that energy distribution of photons incident to a human body is required to evaluate precisely an individual dose based on ESR dosimetry for teeth.     

影响窗玻璃γ辐射响应的电子自旋共振波谱研究

为更好应用于人员剂量估算和事故等级测定,探索了影响窗玻璃电子自旋共振波谱剂量学性质的因素。实验将窗玻璃处理成不同粒度大小,分别研究研磨处理对本底信号和辐射信号的影响。给予窗玻璃样本不同照射剂量,存储在不同条件下,观察温度、光线、时间等对电子自旋共振波谱(ESR)信号的影响。对比了来源不同的窗玻璃剂量响应曲线和最小检测剂量。结果表明,前期样本处理对窗玻璃辐射信号并无明显影响,但会产生机械信号;温度越高,窗玻璃辐射信号越不稳定。高温加热(≥200 ℃,≥5 min)可使照射后的ESR信号衰退至本底信号;透明袋-灯光和黑袋存储条件下的样本结果大致相同:11小时信号强度衰减9%左右,150小时衰减约18%。透明袋-阳光样品:11小时信号衰减了17%,150小时衰减38%。三种存储条件下的样本在150小时左右之后均达到稳定状态;窗玻璃样品在g=2.005 7处ESR信号与吸收剂量线性相关,线性相关性系数因来源于不同生产厂家而有差异。窗玻璃最小检测剂量是4~5 Gy。因此,在窗玻璃作为剂量计的实践中,注意以上问题,建立合理的剂量评估操作程序,可以估算出更为准确的结果。     

辐照剂量率对明胶自由基和性能的影响

为探讨剂量率对明胶分子辐照分解的影响机理,采用电子自旋共振(ESR)、凝胶渗透色谱(GPC)等检测技术分析明胶经剂量率为60、480Gy/min 60 Co以及剂量率为12 000Gy/min加速器辐照0~32kGy剂量后,自由基特征、明胶性能与剂量率的关系。结果表明,未辐照明胶ESR信号微弱,三种辐照方式处理后的明胶均呈现相似的ESR双峰特征;相同吸收剂量下,明胶自由基信号强度由大到小依次为60Gy/min 60 Co辐照明胶、480Gy/min 60 Co辐照明胶和12 000Gy/min加速器辐照明胶;60 Co辐照后自由基信号强度(y)与剂量(x)的线性关系为y=26.983x2+1 641.8x-205.69;辐照明胶特性黏度、平均相对分子质量、凝胶强度和断裂伸长率由高到低依次为480Gy/min 60 Co辐照明胶、12 000Gy/min加速器辐照明胶和60Gy/min 60 Co辐照明胶。可见,高剂量率辐照可能减少明胶中有效长寿命自由基的含量,从而抑制明胶辐照灭菌中性能的劣变。     

Electron paramagnetic resonance dose response studies for neutron irradiated human teeth

The dosimetric response of neutron irradiated human tooth enamel has been investigated using electron paramagnetic resonance (EPR) dosimetry. Continuous energy fast neutrons of mean energy less than 450 keV were produced from the McMaster University 3 MV K.N. Van de Graaff accelerator employing a thick lithium target via ⁷Li(p,n)⁷Be interaction. Prior to its use for various experiments, the gamma dose contamination of the neutron beams was determined at the selected proton beam energies using the tissue-equivalent proportional counter (TEPC). The neutron sensitivity (/Gy-100 mg) of human tooth enamel remained constant for various mean neutron energies ranging from 167 to 450 keV. Similarly, the EPR signal intensity remained independent of the neutron dose rate variation from 0.5 to 2.4 Gy/h.     

Inter-comparison study between human and cow teeth enamel for low dose measurement using ESR

Human and cow teeth enamel samples were separated and irradiated with γ-ray to study radiation-induced radicals as dosimetric material with electron spin resonance (ESR). The enamel spectrum is characterized by two main g-factors g|| = 1.9976 and g⊥ = 2.0019. The dosimetric signal for enamel at g = 2.0019 is ascribed to radicals. The dose response was studied in the range from 200 mGy to 2 Gy. Power dependence, energy dependence and thermal stability had been studied also to determine the optimum conditions for ESR measurements and stability of the signal at room temperature as well. Radical formation efficiency (G-value) of 0.44 ± 0.09 and 0.65 ± 0.13 was obtained for human enamel and cow enamel, respectively. The life time for human enamel and cow enamel were estimated from Arrhenius plot to be 1.1 × 10⁷ years and 7 × 10⁶ years, respectively. The activation energy for human enamel and cow enamel were also calculated from Arrhenius plot to be 1.23 eV and 1.15 eV, respectively. The dose conversion factors for enamel in water and air were calculated to be 0.901 D_water and 0.998 D_air. The combined and expanded uncertainties accompanying these measurements are ±5.79% and ±11.58%, respectively.     

化石的ESR与U系,FT及TL的年龄对比

用铀的线性积累模式计算北京周口店猿人洞牙齿化石的ＥＳＲ年龄，并与Ｕ系、裂变径迹法和热释光法的年龄进行了对比，结果表明釉质齿最适合ＥＳＲ年龄的测定。     

ELECTRON SPIN RESONANCE DATING FOR THE AGE OF PEKING-MAN, LOC.1, ZHOUKOUDIAN, BEIJING

In this paper, we used ESR dating method to measure the accumulative dose of the fossil teeth samples, which are contemporaneous with the Peking-Man. The internal annual dose rate of samples are got by neutron activation analysis and the environmental annual dose rate by highly sensitive TL dosimeters to be embedded in cave deposits in the site. The results of ESR dating are corresponded with the dating results obtained by U-series, FT, TL and paleomagnetic stratigraphical methods on the 3rd, 4th, 7th and 10th layers. Calculation of using different models, the close-equilibrium model, the linear uranium accumulation model and radon loss-linear uranium accumulation model, for travertine, deer teeth and rhinoceros tooth, we obtained the age of the First Peking- Man in the nth layer is 578 ka and gave ages of other layers, from the 1st to the 13th layer in Peking- Man site.     

中能氮离子束辐照小麦种子产生自由基的研究

用ＥＳＲ波谱术研究了室温下中能氮离子辐照小麦种子产生的自由基，发现氮离子贯穿和注入小麦种子产生的自由基浓度随剂量的变化具有不同的特征。对氮离子贯穿小麦种子产生的自由基浓度随剂量率的变化规律也进行了研究。