Effects of specific doses of E-beam irradiation which inactivated SARS-CoV-2 on the nutrition and quality of Atlantic salmon

The contamination of Atlantic salmon with severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)has impeded the development of the cold-chain food industry and posed possible risks to the population.Electron beam(E-beam)irradiation under 2,4,7,and 10 kGy can effectively inactivate SARS-CoV-2 in cold-chain seafood.However,there are few statistics about the quality changes of salmon exposed to these irradiation dosages.This work demonstrated that E-beam irradiation at dosages capable of killing SARS-CoV-2 induced lipid oxidation,decreased vitamin A content,and increased some amino acids and ash content.In addition,irradiation altered the textural features of salmon,such as its hardness,resilience,cohesiveness,and chewiness.The irradiation considerably affected the L*,a*,and b*values of salmon,with the L*value increasing and a*,b*values decreasing.There was no significant difference in the sensory evaluation of control and irradiated salmon.It was shown that irradiation with 2−7 kGy E-beam did not significantly degrade quality.The inactivation of SARS-CoV-2 in salmon is advised at a dose of 2 kGy.

Dynamic characteristics of charging effects on the dielectric constant due to E-beam irradiation： a numerical simulation

A series of synthetic variations of material intrinsic properties always come with charging phenomena due to electron beam irradiation. The effects of charging on the dielectric constant will influence the charging dynamic in return. In this paper, we propose a numerical simulation for investigating the dynamic characteristics of charging effects on the dielectric constant due to electron beam irradiation. The scattering process between electrons and atoms is calculated considering elastic and inelastic collisions via the Rutherford model and the fast secondary electron model, respectively. Internal charge drift due to E-field, density gradient caused diffusion, charges trap by material defect, free electron and hole neutralization, and variation in the internal dielectric constant are considered when simulating the transport process. The dynamics of electron and hole distributions and charging states are demonstrated during E-beam irradiation. As a function of material nonlinear susceptibility and primary energy, the dynamics of charging states and dielectric constants are then presented in the charging process. It is found that the variation in the internal dielectric constant is more with respect to the depth and irradiation time. Material with a larger nonlinear susceptibility corresponds a faster charging enhancement. In addition, the effective dielectric constant and the surface potential have a linear relationship in the charging balance. Nevertheless, with shrinking charging affect range, the situation with a higher energy primary electron comes with less dielectric constant variation. The proposed numerical simulation mode of the charging process and the results presented in this study offer a comprehensive insight into the complicated charging phenomena in electron irradiation related fields.

Investigation on the Effect of Film Thickness on the Surface Morphology, Electrical and Optical Properties of E-Beam Deposited Indium Tin Oxide (ITO) Thin Film

The following article has been retracted due to the fact that the authors practise fraud. The scientific community takes a very strong view on this matter, and the Advances in Materials Physics and Chemistry treats all unethical behavior seriously. This paper published in Vol. 4 No. 10 194-202, 2014 has been removed from this site. ? Title: Investigation on the Effect of Film Thickness on the Surface Morphology, Electrical and Optical Properties of E-Beam Deposited Indium Tin Oxide (ITO) Thin Film ? Authors: Golam Saklayen, Shahinul Islam, Ferdous Rahman, Abu Bakar

Effects of Different Titanium Sub-oxide on the Properties of Titanium Dioxide Thin Films Prepared by E-beam Evaporation Deposition with Ion Auxiliary

TiO2 thin films were prepared with Ti2O3, Ti3O5 and TiO2 as raw materials, by electron-beam evaporation deposition, using O^2- ion beam （ O2 purity up to 99.99% ） as auxiliary means. The crystal structures of the samples were inspected by the X-ray diffraction （XRD） method, and the evaporation character of warious raw materials was analyzed. Transmittance spectra were measured through a U-3310 spectrophotometer （ wavelength ranging from 200 nm to 900 nm）. The refractive index n and the thickness of films were determined from transmission spectra. The experimental results show that the thin films taking Ti2O3 as their raw material have a strong absorption, when taking Ti3O5 and TiO2 as raw materials, the thin films would have good optical properties. The experiments also show that, the crystal structure of all thin films is amorphous before post-annealing and the Ti3O5 is a congruent evaporation phase in the Ti-O system.

Fabrication of Al/AlO_x/Al junctions using pre-exposure technique at 30-keV e-beam voltage

We fabricate high-quality A1/A1Ox/A1 junctions using improved bridge and bridge-free techniques at 30-keV e-beam voltage,in which the length of undercut and the size of junction can be well controlled by the pre-exposure technique.The dose window is 5 times as large as that used in the usual Dolan bridge technique,making this technique much more robust.Similar results,comparable with those achieved using a 100-keV e-beam writer,are obtained,which indicate that the 30-keV e-beam writer could be an economic choice for the superconducting qubit fabrication.

E-beam degradation of thiamphenicol and florfenicol

Thiamphenicol(THA) and florfenicol(FLO) aqueous solutions were irradiated to different doses by 1 MeV electron beams,and redox reactions of THA/FLO and radicals of OH,e_(eq)^- and ~·H were investigated under various conditions.The results showed that at 8 kGy,the decomposition rate of THA and FLO was 97.2%and 98.5%, respectively.Quantitative and qualitative analysis indicated that OH played a key role in E-beam degradation of the THA and FLO in aqueous solutions,and e_(eq)^- and ~·H radicals could initiate the degradation,too.Seven primary products of the THA and FLO degradation were identified.These indicate that E-beam radiation is an effective method to reduce THA and FLO in aqueous solutions.

E-beam radiolysis of aqueous dimethyl phthalate solution

To investigate the influence of radiolysis on kinetics and factors of dimethyl phthalate(DMP),the aqueous DMP solution is degraded by 1.8 MeV E-beam,following pseudo-first-order kinetics.The rate constant of DMP degradation decreased exponentially with increasing initial DMP concentration.The DMP is favorably degraded by radical scavengers under its low concentration and alkaline condition.At high doses,the DMP is attacked by eaq-and ·OH,producing monomethyl phthalate,phthalate acid,and a series of aliphatic carboxylic acids,which are completelymineralized into H2O and CO2.

环境透射电镜中电子束活化气体在材料表面改性方面的机理及应用研究

随着原位透射电子显微技术的不断发展与成熟,在近使役环境中对材料进行高空间与高时间分辨率下的研究得以广泛开展。而环境透射电镜(Environmental transmission electron microscope,E⁃TEM)与材料真实服役环境的一个重要区别在于所引入的环境气氛和样品材料本身都不可避免地受到电子束辐照的影响,因此多数研究都聚焦在如何降低或消除电子束辐照对研究结果的负面干扰。但实际上E⁃TEM中高能电子束可以起到较强的“催化”作用,从而激发出一些原本只有在苛刻条件下才能出现的现象或反应,助力材料改性、新材料合成及相应的微观反应机理的原位研究。本文以近几年作者所在研究团队及合作者利用E⁃TEM中电子束活化CO_(2)和H2气体分子在提升活泼金属耐蚀性、稳定性、辅助陶瓷的室温焊接及样品表面原位清洁等方面的具体应用为例,对电子束促进气固反应、改性材料表面及相关机理进行了介绍,并结合相关实验研究提出了固体表面吸附对电子束诱导气体活化过程的关键作用,更新了之前人们对电子束是通过提高游离态气体反应活性影响气-固间相互作用的认知。

带状电子注驱动的准光谐振腔回旋管

回旋管作为一种重要的真空电子源,能够在毫米波和太赫兹频段生成高峰值以及高平均功率的电磁辐射,在波谱学、雷达、通信、生物医学等领域具有广泛的应用前景。传统的回旋管将不可避免地面对激烈的模式竞争问题,引入准光谐振腔将有望大大减小模式竞争的激烈程度。本文基于电子回旋脉塞理论,将准光谐振腔及带状电子注进行结合,以期实现更高的输出功率及效率。仿真结果表明,在电子电压为40 kV,背景磁场为8.4 T时,设计的准光回旋管能在220 GHz频点处产生6.1 kW的输出,电子效率达到6.1%且在一段时间内能稳定运行。本文结构将可能为高频段乃至高次谐波工作的回旋管设计提供全新方案,从而进一步用于通信、雷达等领域。

E波段矩形环对角双杆行波管的研究

高功率、宽频带是当前科研人员研究行波管的主流方向,中国工信部最新规定E波段的频率范围在71-76 GHz/81-86 GHz。虽然传统的环圈慢波结构有更高的互作用阻抗,但是当其达到E波段及以上由于其结构特点在现实中难以加工,所以难以实现工作在E波段,为了提升输出功率,本文设计了E波段矩形环对角双杆慢波结构行波管的研究,对其进行注波互作用模拟仿真和计算,带状电子注采用19.1 kV的电压,电流为0.14 A的条件下,行波管可获得最大400 W的瞬时输出功率,增益为46.02 dB、电子效率15%。

车桥耦合振动作用下连续梁桥的声辐射特性

为了探究城市轨道交通某高架线连续梁辐射噪声特性及对周围环境的影响,将列车-桥梁耦合振动理论与桥梁结构声辐射分析的边界元法相结合,以北京地铁5号线某高架段三跨连续变截面箱梁桥为研究对象,编写计算程序求解桥梁的振动响应,将各跨竖向振动计算结果作为声学边界条件输入到Virtual.lab桥梁边界元模型中,求解连续梁的辐射噪声。通过时域分析与频域分析相结合的方法,分析桥梁结构声辐射时域声压、声压级变化以及声辐射的频谱特性。同时与振动数据对比,结果表明:桥梁结构的噪声声压时程与竖向振动加速度时程变化规律比较相似,两者几乎在同一时刻出现峰值;通过各跨声压级云图可以看出梁顶面和底面是噪声最大区域,桥梁两侧噪声沿水平方向衰减较大,而沿竖直方向变化并不明显;通过频域分析可以看出桥梁结构噪声主要以200 Hz以内的低频噪声为主,声压级在频域上的分布规律与竖向振动加速度频谱呈现一定的相似性。

考虑局部屈曲加劲钢箱形构件极限承载力的纤维梁柱模型

大型桥梁加劲钢箱形构件的极限承载力会受到板件局部稳定性能的影响,而目前尚缺乏成熟的可直接计入局部屈曲的高效计算模型。归纳总结国内外钢构件计算方法对局部屈曲的处理方式,明确以有效应力法即采用板件(或加劲板)平均受压应力-应变曲线简化局部屈曲效应的研究思路。通过有限元程序ANSYS二次开发钢板拉压非对称本构模型,提出一种可直接计入局部屈曲的纤维梁柱模型。材料本构模型中受压应力-应变曲线通过小型的加劲板板壳模型得到,且全面考虑了焊接残余应力与几何缺陷。搜集已开展的钢箱梁、钢桥塔及钢拱肋的稳定性试验,采用提出的纤维梁柱模型、板壳模型与传统弹塑性梁柱模型进行分析,展示截面纤维划分策略,验证文中纤维梁柱模型的可靠性与高效性;通过设置不同的缺陷参数,探讨缺陷水平与局部屈曲对各个构件极限承载力的影响。研究表明,随着缺陷水平的严重,局部屈曲会显著降低极限承载力,提出的纤维梁柱单元模型能够有效地预测加劲钢箱形构件的极限承载力,具有较广泛的应用前景。

Contribution for Efficient Planning of Millimeter Wave Frequencies: Case of the 80 GHz E-Band for High-Speed Broadband Transmissions

Due to the very high demand for Internet data capacity from mobile and fixed customers as well as the saturation of conventional frequency bands by numerous services, many countries have opened the E band, for broadcasting services. E-band involves the creation of a significant number of links in a given area. The present work addressed the problem that arises in the context of transmission is that of assigning the frequencies of this band to these multiple transmission links. The aim of this work is to study and plan the radio links of the 80 GHz frequency and to implement them in a tool in order to define an optimal distribution on the telecommunications network by guaranteeing maximum flow of data traffic while minimizing the interference. The contribution of this work is part of its unique subject: the planning of E-band frequencies for improving the quality of service of transmission in the network of telecommunications operators. Also, it intends to contribute to the resolution of unsatisfied situations of poor planning of E-band radio frequencies in telecommunications networks. With the aim of opening several opportunities for alternative high-speed data transport solutions, our work has helped prove that E-band transmission links are very efficient with capacities in the gigabyte range.

E型波导振荡器反转永磁引导系统初步设计

开展了E型波导振荡器永磁引导系统的物理与设计研究。对强流相对论电子束在理想方波形反转引导磁场中的传输条件进行了理论分析,给出了相对论条件下轴对称复合场中电子束的傍轴轨迹方程和最小引导磁场的计算公式。根据该理论分析,针对C波段E型波导振荡器高频互作用区的结构特点,设计了反转永磁引导系统,同时给出了漂移管内各个磁场分量的表达式。该系统由轴径向磁化空心永磁体组合产生反转引导磁场,永磁体的总质量约为2.5 kg。采用爆炸发射阴极,展示了强流相对论电子束在该引导磁场中的传输特性。研究结果显示,所设计反转永磁引导系统可引导400 kV、580 A的环形电子束稳定通过半径为6 mm的漂移管,带入器件,得到112.5 MW的4.8 GHz微波输出功率,效率为48.49%,确定了反转永磁引导系统应用于E型波导振荡器的技术可能性。

扭转梁悬架和E型四连杆悬架对比分析

乘用车后悬架类型较多,主流车后悬架大量采用的是扭转梁悬架和E型四连杆悬架,但两种悬架形式在布置空间、价格、性能等方面均存在一定区别。文章从结构、承载能力、性能等维度对主流车常见的两种后悬架结构——扭转梁悬架和E型四连杆悬架进行对比分析。结果可知,扭转梁悬架仅在后备箱空间、轮胎磨损方面有优势,而E型四连杆悬架在承载能力、四驱空间、操纵稳定性、平顺性方面都具有优势。建议成本优先的A0、A级车采用经济型扭转梁悬架;操稳和舒适优先的A、B级车采用成本较高的E型四连杆悬架。该分析结论为汽车研发期间后悬架类型的选择提供了一定的参考依据。

电激励重复频率非链式HF激光器

采用电子束和气体放电两种激励方式开展重复频率非链式HF激光研究。基于全固态脉冲功率源SPG-200建立了重复频率HF实验装置,探索了产生重频大面积均匀电子束的技术途径,利用法拉第筒对进入激光气室的电子束的轴向均匀性进行了诊断,开展了激光器输出特性研究和重频实验调试,在C2H6∶SF6=0.035,总气压为35 kPa时,激光器输出能量最大约为4.8 mJ,并实现了最高30 Hz的HF激光稳定输出。采用峰化电容及紫外自动预电离技术设计研制了放电激励重频HF激光器,研究了SF6气体放电特性和重频运行稳定性。研究发现SF6气体放电具有典型的辉光放电、电压维持和电弧放电三阶段特征。在充电电压为28 kV,总气压为12 kPa,C2H6含量为8%时,放电激励HF激光器最大脉冲能量约600 mJ,比能量输出达到8.5 J/l,激光器的电光转换效率约为2.5%。该激光器在150 Hz实现了重频输出,首脉冲能量〉500 mJ,在10 Hz时稳定输出能量约为200 mJ。

两种方法制备ITO薄膜的红外特性分析

比较了用电束加热蒸发法和直流磁控溅射法制备的氧化锡铟 (ITO)薄膜在红外波段的光学特性 实验发现 ,通过直流磁控溅射在常温下制备的ITO薄膜在红外波段折射率稳定、消光系数小 ,比电子束加热蒸发制备的膜有较高的透过率 在波长 1 5 5 0nm附近的透过率可达 86%以上 ,消光系数约为 0 0 4 ,方电阻最低为 1 0 0Ω/□ .

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2.10 kGy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15 d。采用单一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15 d时,0.56 kGy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。

锂磷氧氮(LiPON)薄膜电解质和全固态薄膜锂电池研究

采用电子束热蒸发Li3 PO4与氮等离子体辅助相结合的方法制备了含氮磷酸锂 (LiPON)电解质薄膜 ,已测得该非晶态电解质薄膜在温度为 3 0 0K时的离子导电率为 6 0× 10 -7S/cm ,电子电导率低于 10 -10 S/cm ,电化学稳定窗口为 5 0V .以脉冲激光沉积法 (PLD)制备的非晶态Ag0 5V2 O5薄膜为阴极 ,真空热蒸发法制备的金属锂为阳极 ,LiPON薄膜为电解质 ,成功地制备了一个新的Li/LiPON/Ag0 5V2 O5全固态薄膜锂电池 .该电池以 14 μA/cm2 电流充 /放电时 ,首次放电容量达到 62 μAh·cm-2 ·μm-1,10次循环后容量衰减缓慢 ,衰减率约为 0 2 % ,循环寿命达到 5 5

氧和氩等离子辅助电子束蒸发制备高质量ZnO薄膜

采用等离子辅助电子束蒸发技术制备高纯金属锌膜,然后在氧气气氛下经高温热处理得到氧化锌的多晶薄膜。X射线衍射谱的结果表明:未经热氧化样品由金属锌和氧化锌纳米晶组成,随着热氧化温度的升高氧化锌纳米晶粒长大,形成纳米氧化锌多晶薄膜且薄膜结晶性增强;光致发光谱表明:样品均具有较强的紫外自由激子发光。由于未经热氧化样品中氧化锌纳米晶粒较小,具有较强的量子限域效应,因而经高温氧化后样品发光峰有较大红移。随着热氧化温度的进一步升高,束缚激子发射随热氧化温度升高而减弱,且发光峰位随热氧化温度升高出现蓝移;变温光致发光谱表明:紫外发光主要来自自由激子发射。