高能粒子辐照对零膨胀微晶玻璃光学性质和面形光学稳定性的影响

研究了高能电子，高能质子对ＶＯ２微晶玻璃辐照前后光性质和面形光学稳定性的影响，研究结果表明，高能电子辐照能引起微晶玻璃面形明显变化，且使ＶＯ２微晶玻璃强烈着色。高能质子辐照没引起面形明显变化，高能质子辐照对反射光谱特性没有影响。     

高能粒子辐照对InGaN材料电子浓度和光致发光的影响

研究了高能粒子辐照对InGaN材料的电子浓度变化和PL光谱强度在不同温度下变化的影响.高能粒子辐照使InGaN材料的电子浓度明显增加,表明辐照损伤在InGaN材料中产生的本征点缺陷主要是类施主点缺陷,高能粒子辐照产生的高浓度本征点缺陷最终将缺陷的Fermi能稳定在EFs处.在低温和室温条件下,InGaN材料的PL光谱随高能粒子辐照剂量的增加而变宽,且PL峰能向高能方向偏移.InGaN材料的PL光谱随辐照剂量的增加而变宽,原因是该材料中电子浓度的增加以及k选择的紊乱.研究结果表明,与一般的太阳能电池材料GaAs和GaInP相比,InGaN材料具有非常优越的抗辐照性能.     

γ辐照和电子束辐照对猪肉火腿肠质量的影响研究

比较研究了经不同剂量的γ辐照(GR)(0,5,10,15,20 kGy)和电子束辐照(EB)(0,5,10,15,20kGy)处理的猪肉火腿肠在30℃下储藏10 d过程中的品质(TBARS值、硬度、色泽),感官特性和细菌总数的变化.结果显示,GR辐照与EB辐照对猪肉火腿肠在储藏过程中脂质氧化、硬度、色泽和感官特征变化的影响相似(P≥0.05);然而,经GR辐照处理的样品的细菌总数显著小于经EB辐照处理的样品细菌总数(P<0.05),并且当GR辐照剂量增至10 kGy,样品中细菌总数得到有效抑制,而对火腿肠的品质和主要感官特征(色泽,咀嚼性和味道)没有显著影响(P≥0.05).     

辐照对Tb~(3+)掺杂硅酸盐玻璃结构和发光性能的影响

采用高温熔化工艺制备出Tb3+掺杂硅酸盐玻璃,研究了高能辐照对该玻璃结构和发光性能的影响。结果表明,高能辐照后,Tb3+掺杂硅酸盐玻璃的结构发生变化,表现为两个方面:(1)是部分Tb3+离子被氧化为(Tb3+)+离子;(2)是玻璃体内产生大量色心。辐照对Tb3+掺杂硅酸盐玻璃的发光强度影响较大,发光强度随辐照剂量的增大而降低;然而,辐照对Tb3+掺杂硅酸盐玻璃的发光余辉影响较小,发光余辉基本不随辐照剂量的增加而变化。     

聚四氢呋喃醚二醇相对分子质量对聚氨酯耐辐照性能的影响

文中针对聚氨酯（PU）软段耐辐照性能差制约其在高能辐照领域的应用，采用不同相对分子质量的聚四氢呋喃醚二醇合成了一系列PU材料，研究了其辐照前后的结构和性能。结果表明，当多元醇相对分子质量为650时，软段排列紧密，可有效抵抗电子辐照对材料的损伤，因而辐照后PU的力学性能保持完好。随着多元醇相对分子质量增加至1000，软段尺寸变大，辐照后PU易发生氧化降解，PU的力学性能显著下降。当多元醇的相对分子质量进一步增加，软段内分子链超过其临界缠结长度，分子链相互缠结，可在一定程度上抑制软段对辐射的阻抗作用，辐照后样品的力学性能可保持原始样品的70%。     

γ辐照对纤维素纳米纤丝膜结构及性能的影响

目的 为了平衡60Coγ 射线辐照灭菌纤维素纳米纤丝(CNFs)膜的辐照剂量与薄膜性能之间的关系,探究60Coγ 射线辐照剂量对纤维素纳米纤丝(CNFs)膜结构和性能的影响,旨在得到对CNFs膜各项性能指标影响较小的辐照剂量.方法 以蔗渣浆板为原料,采用机械研磨法制备CNFs,采用浇筑法制备CNFs膜,用5～50 kGy的 γ 射线辐照CNFs膜,对膜的表面形貌、化学结构、结晶度、热稳定性、力学性能及阻隔性能等进行测定.结果 随着辐照剂量的增加,CNFs的纤丝状开始变得粗细不均,说明辐照致使CNFs发生了氧化降解;此外,经辐照处理的CNFs膜的拉伸强度下降,而弹性模量增强,当辐照剂量为5 kGy时,样品膜的拉伸强度仅仅降低了1.8％,而弹性模量增加了15.1％,此时CNFs膜的力学性能最优异;阻隔性实验结果表明,辐照对CNFs膜的阻隔性没有显著性影响,但经10 kGyγ 射线辐照处理的CNFs膜的氧气透过量和水蒸气透过量相较于未辐照处理的样品膜依次下降了约6.2％和4.1％,此时,样品膜阻隔性能最佳;此外,γ辐照会使CNFs膜的亲水性下降,结晶度增大,热稳定性降低.结论 适量的60Coγ 射线辐照可以使CNFs膜的刚性有一定程度的增加,且薄膜的其他各项性能受影响较小,60Coγ 射线辐照的CNFs膜在包装中具有一定的应用前景.     

茶叶中稀土元素的电感耦合等离子体质谱检测方法研究

针对目前茶叶中稀土检测方法中存在的样品前处理复杂、灵敏度低等问题,研究了茶叶中15种稀土元素的检测方法.该方法采用微波消解方法处理茶叶样品,用电感耦合等离子体质谱同时测定15种元素,测定茶叶标准物质GBW 07605和GBW 10016表明,各元素结果与标准值一致.对茶叶中稀土元素的实际应用显示,使用该方法简单、快捷、准确,可以获得满意结果.     

RTV胶在空间高压阵二次放电防护技术中的应用研究

室温硫化硅橡胶(RTV胶)可以有效防止空间高压太阳阵产生二次放电事件.本文以地面模拟实验为基础,研究RTV胶在空间高压阵抗二次放电方面的防护作用.实验表明RTV胶明显提高了高压阵二次放电阈值电压;经高能电子辐照后,RTV胶防护样品串间发生耦合放电.通过对经高能电子辐照前后样品RTV胶的红外分析对比,讨论了空间高能电子辐照环境对RTV胶防护二次放电性能的影响.     

气相色谱检测含脂辐照食品中的碳氢化合物

含脂食品经过γ辐射会产生碳氢化合物,本研究通过检测这些特定的碳氢化合物,从而确定含脂食品是否经过辐照。通过弗罗里层析柱和气相色谱分离碳氢化合物,再用火焰离子化检测器（FID）进行检测。在1kGy和5kGy两种剂量的Co60辐照下,待检样品中被明显检出含1-14：1、15：0、1,7-16：2、1-16：1、17：0等碳...     

BaLiF3微晶辐照损伤及其稀土掺杂抑制

用电子顺磁共振和热释发光对ＢａＬｉＦ３微晶的Ｘ射线和γ射线辐照损伤及稀土掺杂对其辐照损伤的抑制作了研究，发现Ｘ射线造成的辐照损伤在自然条件下仅数日就可以恢复；而因γ射线辐照所造成的辐照损伤则较难恢复，但其抗辐照性能在掺入适宜的稀土离子如Ｌａ＾３＋、Ｙｂ＾３＋后可得到改善，这表明将其用于γ射线等高能粒子的探测亦是很有希望的。     

Development of current-based microscopic defect analysis methods and associated optical filling techniques for the investigation on highly irradiated high resistivity silicon detectors

Current based microscopic defect analysis methods such as current deep level transient spectroscopy (I-DLTS) and thermally stimulated current (TSC) have been further developed in accordance with the need for the defect analysis of highly irradiated (Φ_n > 10¹³ n/cm²) high resistivity silicon detectors. The new I-DLTS/TSC system has a temperature range of 8 K ≤ T ≤ 450 K and a high sensitivity that can detect a defect concentration of less than 10¹⁰/cm³ (background noise as low as 10 fA). A new filling method using different wavelength laser illumination has been applied, which is more efficient and suitable than the traditional voltage pulse filling. It has been found that the filling of a defect level depends on such factors as the total concentration of free carriers generated or injected, the penetration length of the laser (laser wavelength), the temperature at which the filling is taking place, as well as the decay time after the filling (but before the measurement). The mechanism of the defect filling can be explained by the competition between trapping and detrapping of defect levels, possible capture cross section temperature dependence, and interaction among various defect levels in terms of charge transferring. Optimum defect filling conditions have been suggested for highly irradiated high resistivity silicon detectors.     

基于热点可视化的茶家具造型设计

目的 对市场茶家具产品造型进行设计规律的探索和应用.方法 以产品迭代更新规律和密度分析原理为基础,借助信息可视化的方法直观地展现茶家具产品造型变化的规律.通过对市场上知名家具品牌茶家具样本的收集、筛选和处理得到20个实验样本,利用同一色相的色彩叠加明度变化来得到茶家具产品造型上的设计热点分布图,并将其与茶家具造型设计相结合形成设计方法.结果 随着样本的叠加,整体所呈现的色彩明度在加深,逐渐凸显出一个色彩明度最深的区域,而其周边呈现出不同的色彩明度,根据呈现的结果启示茶家具的造型设计实践.结论 市场产品是成熟的用户需求解决方案和时尚潮流等的载体,在一定程度上能反映一定时间内设计趋势和热点,将设计热点可视化能为产品造型设计提供依据和方向.     

Application of a thermoluminescence method for the detection of irradiated spices

Food irradiation is extremely effective at reducing food-borne illness as well as losses caused by infestation and contamination. Despite the well-established regulations that permit irradiation to control pathogens in spices, there are no widespread methods to detect previously irradiated food. Therefore, it has become necessary to develop new detection and dose determination methods for food subjected previously to irradiation. The present work deals with the application of the thermoluminescence (TL) phenomenon to detect irradiated spices. The process is based upon the thermoluminescence properties exhibited by the polymineral content of the irradiated specimen. After separating the organic material, it is possible to extract some polymineral substances that are suitable for thermoluminescence analysis due to interaction of the spice to ionising radiation. The method was successfully applied to examine irradiated and non-irradiated paprika of Mexican origin. The spice was irradiated with gamma rays at doses of 5, 10 and 15 kGy. The separated thermoluminescent polymineral was found to be composed mainly of quartz and feldspar. The thermoluminescence glow curve of the irradiated specimen shows a wide band peaked 228, 268 and 336 degrees C, resembling closely the combined TL of quartz and feldspars. The method allows for the determination of the retrospective dose exposure.     

一种用于印刷图像防伪的水印算法设计与实现

阐述了基于DCT变换域的数字水印理论和算法,并根据相关理论模型,提出了一种在离散傅里叶变换中实现的、可用于印刷品防伪的数字水印嵌入算法。研究表明与传统的LSB算法和Patchwork算法相比,该算法有较好的抗攻击能力。给出了系统的水印嵌入算法和水印提取流程设计的过程。实践证明,基于DCT变换域的数字水印算法能确保水印的不可见性,并保持较好的鲁棒性,实现了印刷图像载体数字版权的保护,并可检测出用此算法嵌入印刷图像中的不可见标记。最后通过实验验证了此算法的可行性、可靠性和有效性,为印刷品版权保护提供参考和借鉴。     

茶叶掺杂物中CaO、MgO的测定

本文提出以CaO、MgO作为检测茶叶掺杂物石膏、滑石粉的标识物,采用干灰化法处理茶样,并用络合滴定法对CaO、MgO进行测定,经长期实际检测表明,检测结果稳定可靠,并经与火焰原子吸收分光光度法比对,结果满意。该法简便易用,适合一般茶叶厂家及相关检测部门采用。     

基于BP神经网络的个性化多功能茶几设计研究

目的 通过分析消费者感性需求和多功能茶几产品形态设计要素,建立二者之间回归的联系模型,完成多功能茶几产品的个性化设计,解决茶几产品无法按照用户消费需求设计制造的难题。方法 首先运用语义差异法获取消费者对茶几产品的感性意象评价值,并利用因子分析法对评价值进行归纳整理,其次按照茶几产品设计要素对其进行模块解构,并对各部分模块进行数值化编码,再次根据整理的感性意象评价值和模块数值训练茶几产品BP神经网络,建立二者间映射关系,最后实施二次语义差异法问卷实验,验证BP神经网络的准确性。结果 根据训练的茶几产品BP神经网络可预测出感性评价值最大的茶几产品造型,实验结果验证了茶几产品BP神经网络模型的准确性,为茶几产品的个性化设计提供了有利的支撑。结论 此方法提高了茶几产品的设计效率,提升了茶几产品设计的合理性,解决了家具设计者无法精准按照用户主观需求完成客观产品设计的难题,为以消费者需求市场为导向的产品设计制造提供了有益的参考和指导。     

Optimization of informative spectral variables for the quantification of EGCG in green tea using Fourier transform near-infrared (FT-NIR) spectroscopy and multivariate calibration

Epigallocatechin-3-gallate (EGCG) is credited with the majority of the health benefits associated with green tea consumption. It has a high economic and medicinal value. The feasibility of using different variable selection approaches in Fourier transform near-infrared (FT-NIR) spectroscopy for a rapid and conclusive quantitative determination of EGCG in green tea was investigated. Graphically oriented multivariate calibration modeling procedures such as interval partial least squares (iPLS), synergy interval partial least squares (siPLS), and genetic algorithm optimization combined with siPLS (siPLS-GA) were applied to select the most efficient spectral variables that provided the lowest prediction error. The performance of the final model was evaluated according to the root mean square error of prediction (RMSEP) and coefficient of determination (R(2)) for the prediction set. Experimental results showed that the siPLS-GA model obtained the best results in comparison to other models. The optimal models were achieved with R(2)(p) = 0.97 and RMSEP = 0.32. The model can be obtained with only 36 variables retained and it provides a robust model with good estimation accuracy. This demonstrates the potential of NIR spectroscopy with multivariate calibration methods to quickly detect the bioactive component in green tea.     

Picosecond time-resolved bleaching dynamics of self-assembled quantum dots

Picosecond bleaching dynamics of vertically stacked self-assembled quantum dots (QDs) is investigated by means of time-resolved pump-probe differential reflection spectroscopy (TRDR) at room temperature (RT). We observe that the absorption spectrum, which represents the QD density of states at RT, is strongly shifted with respect to the photoluminescence spectrum. This shift can not be interpreted by carrier emission and re-trapping alone. TRDR allows us to study the dynamics of the pump generated carriers within the QDs. From the time-resolved measurements, we detect that the bleaching decay time has a strong energy dependence and is dominated by radiative and nonradiative recombination at low energy and by carrier emission at high energy.     

聚丙烯无纺布活性包装材料的制备及性能研究

目的研究新型的抗菌保鲜、力学性能高的聚丙烯无纺布活性包装材料。方法以聚丙烯无纺布为包装基材,通过浸渍涂覆的方法向无纺布中添加不同组分的壳聚糖和茶多酚,然后通过透气性、保鲜性、抗菌性以及FTIR等来表征研究茶多酚添加量对活性材料性能的影响。结果由红外分析可知,茶多酚的加入提高了壳聚糖与基材的相容性;由保鲜实验可知,材料可延缓杨梅的腐败变质,减缓了可滴定酸含量的下降速率,能减少蒸腾作用引起的杨梅质量损失,延长了货架期(从4 d延长至8~10 d),起到了很好的保鲜作用;由抑菌试验可知,材料具有很好的抑菌效果。当茶多酚质量分数为1.5%时,其抑菌效果最好,抑菌率最大为99.1%。结论通过对制备的活性包装材料与空白对照组的各种性能相比较,可知聚丙烯活性包装材料具有很好的保鲜抑菌效果,并且具有较高的力学性能,当壳聚糖和茶多酚质量分数均为1.5%时材料的性能最佳。     

Application of photostable quantum dots for indirect immunofluorescent detection of specific bacterial serotypes on small marine animals

An indirect immunofluorescence approach was developed using semiconductor quantum dot nanocrystals to label and detect a specific bacterial serotype of the bacterial human pathogen Vibrio parahaemolyticus, attached to small marine animals (i.e.?benthic harpacticoid copepods), which are suspected pathogen carriers. This photostable labeling method using nanotechnology will potentially allow specific serotypes of other bacterial pathogens to be detected with high sensitivity in a range of systems, and can be easily applied for sensitive detection to other Vibrio?species such as Vibrio cholerae.