Irradiation effect on strain sensitivity coefficient of strain sensing fiber Bragg gratings

The effect of irradiation on the strain sensitivity coefficient of strain sensing fiber Bragg gratings （FBGs） has been investigated through experiments. FBGs were fabricated in single mode fibers with 3 tool% Ge-concentration in the core and with a H2-1oading treatment. In experiments, the FBGs were subjected to y-radiation exposures using a Co6~ source at a dose-rate of 25 Gy/min up to a total dose of 10.5 kGy. The GeO defect in fiber absorbs photons to form a GeE＇ defect; the interaction with H2 is a probable reason for the y-radiation sensitivity of gratings written in hydrogen loaded fibres, The effect mechanism of radiation on the strain sensitivity coefficient is similar to that of radiation on the temperature sensitivity coefficient. Radiation affects the effective index neff, which results in the change of the thermo-optic coefficient and the strain-optic coefficient. Irradiation can change the strain sensitivity coefficient of FBGs by 1.48%-2.71%, as well as changing the Bragg wavelength shift （BWS） by 22 pm-25 pm under a total dose of 10.5 kGy. Our research demonstrates that the effect of irradiation on the strain sensitivity coefficient of FBG is small and that strain sensing FBGs can work well in the radiation environment.

Estimation of enhanced low dose rate sensitivity mechanisms using temperature switching irradiation on gate-controlled lateral PNP transistor

The mechanisms occurring when the switched temperature technique is applied,as an accelerated enhanced low dose rate sensitivity(ELDRS)test technique,are investigated in terms of a specially designed gate-controlled lateral PNP transistor(GLPNP)that used to extract the interface traps(Nit)and oxide trapped charges(Not).Electrical characteristics in GLPNP transistors induced by ^(60)Co gamma irradiation are measured in situ as a function of total dose,showing that generation of Nit in the oxide is the primary cause of base current variations for the GLPNP.Based on the analysis of the variations of Nit and Not,with switching the temperature,the properties of accelerated protons release and suppressed protons loss play critical roles in determining the increased Nit formation leading to the base current degradation with dose accumulation.Simultaneously the hydrogen cracking mechanisms responsible for additional protons release are related to the neutralization of Not extending enhanced Nit buildup.In this study the switched temperature irradiation has been employed to conservatively estimate the ELDRS of GLPNP,which provides us with a new insight into the test technique for ELDRS.

Experimental investigation of pre-irradiation effect on radiation sensitivity of temperature sensing fiber Bragg gratings

The effect of pre-irradiation on radiation sensitivity of fiber Bragg gratings （FBGs） is verified experimentally. FBGs are fabricated in photosensitive optical fibers and single mode fibers with Ce-concentration in a range from 3 mol% to 23.37 mol% in the core. In experiments, the FBGs are subjected to twice v-radiation exposures to a Co^60 source at a dose-rate of 0.1 Gy/s up to a total dose of 50 kGy. Pre-irradiation treatment can reduce the temperature sensitivity variation of FBGs by 18.12%-35.91%, as well as Bragg wavelength shift （BWS） by 8%-27.08 %. Our research demonstrates that pre-irradiation treatment is a feasible method to improve the radiation tolerance of FBGs.

Effects of Gamma-Ray Irradiation on Dielectric Surface Breakdown of Polybutylene Naphthalate and Polybutylene Terephthalate Under Reduced Pressure

With the increasing application of electric and electronic devices in space and nuclear power stations, the polymeric insulation materials are inevitably exposed to various kinds of environments. Accordingly, it becomes necessary to investigate the effects of the radiation and air pressure on insulation materials. This paper describes the effects of gamma-ray irradiation and reduced pressure on dielectric breakdown of polybutylene naphthalate (PBN) and polybutylene terephthalate (PBT) by applying a DC pulse voltage. Both PBN and PBT were irradiated in air up to 100 kGy and then up to 1 000 kGy with a dose rate of 10 kGy/h by using a60Co gamma-source. The effects of total dose and reduced pressure on the time to dielectric breakdown and discharge quantity were discussed. Obtained results show that, while increasing the total dose, the discharge quantity decreased with PBN, but increased with PBT. With decreasing the air pressure, the discharge quantity increased with PBN, but decreased with PBT. With increasing the total dose, the time to dielectric breakdown increased with PBN, but decreased with PBT. With decreasing the air pressure, the time to dielectric breakdown increased with both PBN and PBT. The experimental results suggest that the chemical structure of polybutylene polymers plays a main role in the result of radiation reaction, which is related to cross-linking and degradation reaction.

The Influence of <i>γ</i>-Irradiation on Structuration in Solutions of BNR and Properties of Films

Studied influence of γ-irradiation on stucturation in butadiene nitrile rubber solution and films properties studied also. Structuration in solutions has defined by rheological method with rotation viscometer. Shown influence of solvent nature (methyl ethyl ketene: toluene) to strength properties and structures of films obtained from this solvents. It has been found that during irradiation of solvent, films and butadiene nitrile rubber solution characteristic viscosity η increased, increasing of Huggins constant (К') observed as well. Changing of spatial mesh of polymers occurs at the cost of changed size of macromolecule balls. Shown, that in the issue of crossing the properties including thermo dynamical features of films and butadiene nitrile rubber solution has changed.

Charge-sensitive deep level transient spectroscopy of helium-ion-irradiated silicon,as-irradiated and after thermal annealing

Electrically active defects in the phosphor-doped single-crystal silicon, induced by helium-ion irradiation under thermal annealing, have been investigated. Isothermal charge-sensitive deep-level transient spectroscopy was employed to study the activation energy and capture cross-section of helium-induced defects in silicon samples. It was shown that the activation energy levels produced by helium-ion irradiation first increased with increasing annealing temperature, with the maximum value of the activation energy occurring at 873 K, and reduced with further increase of the annealing temperature. The energy levels of defects in the samples annealed at 873 and 1073 K are found to be located near the mid-forbidden energy gap level so that they can act as thermally stable carrier recombination centres.

Effect of Irradiation Crosslinking on Polyethylene Terephthalate Flame-Retardant Fabric

Irradiation cross-linking of flame-retardant polyethylene terephthalate( FR-PET) fabric with the presence of trimethylolpropane triacrylate( TMPTA) was studied. Thermal gravimetric( TG) analysis,differential scanning calorimetry( DSC) and scanning electron microscopy( SEM) were used to analyze the effects of irradiation crosslinking on structure and property of FR-PET fabric with TMPTA. The cross-linking was promoted by the introduced sensitizer. The gel content was 5.94% at the lower dose of 90 kGy and it arrived at the highest level of 13.01% with the increased doses. There were no melt drips of FR-PET fabric after irradiation cross-linking while the flame retardance disappeared at the time of combustion. The melting temperature of irradiated fabric decreased and TG analysis showed that the onset temperature of degradation of FR-PET fabric and the amount of nonvolatile residue at 800℃ increased as the irradiation dosage increased,but it changed a little compared with the pure FR-PFT fabric. SEM photographs showed that the residue char of irradiated PET fabrics after vertical test remained the intrinsic crossed structure,and the enlarged graph showed that the char was uniformly distributed and it was tight honeycombs structure.

智能激光3D投影空间目标辐射照度校准技术

由于激光3D投影系统的光路复杂,且受空间目标的形状和大小的影响,导致在特定空间内难以取得理想的投影效果,使得投影目标与实际投影点之间存在较大的偏差,因此,提出一种辐射照度校准方法。分别利用矩形、圆形两种不同形状的辐射面和敏感面搭建辐射照度测量仪,得到4种不同辐射照度测量结果;利用斯忒藩-玻尔兹曼全辐射定律,对测量结果校准,进而完成对智能激光3D投影空间目标辐射照度的校准。实验结果表明,所提方法辐射照度校准结果与实际结果基本一致,且辐射照度校准误差保持在6 W·m^(2)以内。

基于辐照交联改性的电容器用聚丙烯薄膜介电性能

针对高温强电场环境下传统聚丙烯(polypropylene,PP)薄膜存在击穿场强低、电导损耗高的问题,提出了一种基于γ射线辐照交联的PP薄膜改性方法,研究了辐照剂量和敏化剂等参数对PP薄膜介电性能的影响;制备了含有三羟甲基丙烷三丙烯酸酯(trimethylolpropanetriacrylate,TMPTA)、季戊四醇三丙烯酸酯(pentaerythritol triacrylate,PETA)等敏化剂的PP薄膜,将PP薄膜在60Co-γ射线下进行0、5、10 kGy(1 Gy=1 J/kg)的辐照处理;分析了辐照交联PP薄膜的分子链与聚集态结构表征,研究了高温强场下交联结构对PP薄膜电导率与击穿场强的影响规律。研究表明:高能射线辐照可在PP薄膜内部形成三维网状结构,增强分子链间作用力与热稳定性,有效抑制PP内部载流子输运,显著提升PP薄膜的高温介电性能。115℃下交联度为25.04%的改性PP薄膜电导率降低64.2%,击穿场强提升16.6%,最高理论储能密度达3.78 J/cm3。该方法表明辐照交联改性手段能够有效提升PP薄膜的高温介电性能。

WO_(3)/GF/PDMS力敏/电磁屏蔽结构的抗γ辐照研究

提出了一种既具有抗伽马(γ)辐照又具有电磁屏蔽性能的氧化钨(WO_(3))/石墨烯泡沫(GF)/聚二甲基硅氧烷(PDMS)复合力敏结构。该结构以GF良好的三维多孔网状结构所形成的良好导电网络来实现电磁屏蔽。WO_(3)粉填充来实现γ辐照屏蔽。通过真空辅助法,将WO_(3)/PDMS溶液回填进入GF中制得。通过^(60)Co-γ射线对复合结构进行不同剂量的辐照,并对辐照前后复合结构的电磁屏蔽性能、电导率及力敏特性进行了测试分析。结果表明:所制备的复合结构随着辐照剂量的增加,依旧保持较好的电磁屏蔽效能、导电性和良好的重复性与稳定性。该复合力敏结构具有较好的γ屏蔽效果和电磁屏蔽性能,为柔性可穿戴器件应用于辐照及电磁辐射环境中提供了参考。

基于TDDFT的四种含能化合物分子在紫外光下的响应

采用含时密度泛函理论(TDDFT)计算了NTO、RDX、HMX、CL-20分子的光吸收谱、紫外光激发下分子的结构以及差分电荷密度随时间的演化。TDDFT模拟结果对比实验的感度趋势表明,在紫外光照下的激发态电子数目可作为分子水平上电子稳定性的描述符,其电子稳定性层级为NTO>CL-20>HMX>RDX。硝基脱离难易程度可作为分子水平上辐照感度的描述符,其感度层级为CL-20~RDX>HMX>NTO,NTO分子表现出最低的辐照感度。这4种火炸药分子在紫外光下发生的主要反应是脱氢、开环、硝基分离、硝基脱氧形成氮气,其中强吸电的硝基向周围转移电子起到了关键作用。不同光强诱导硝基上发生不同的电荷转移,产生不同的分解产物。模拟结果表明,光场较弱时硝基脱落形成二氧化氮,主要分解产物为二氧化氮、氢自由基。强光场下部分硝基脱氧形成亚硝基,若硝基解离能足够大,硝基可完全脱氧并脱离环状结构形成氮气,反应的中间产物包括氢、氧自由基、二氧化氮、亚硝基以及氮气分子。

Unusual He-ion irradiation strengthening and inverse layer thickness-dependent strain rate sensitivity in transformable high-entropy alloy/metal nanolaminates:A comparison of Fe_(50)Mn_(30)Co_(10)Cr_(10)/Cu vs Fe_(50)Mn_(30)Co_(10)Ni_(10)/Cu

In this work,we prepare transformable HEA/Cu nanolaminates(NLs)with equal individual layer thick-ness(h)by the magnetron sputtering technique,i.e.,Fe_(50)Mn_(30)Co_(10)Cr_(10)/Cu and Fe_(50)Mn_(30)Co_(10)Ni_(10)/Cu,and comparatively study He-ion irradiation effects on their microstructure and mechanical properties.It ap-pears that the as-deposited HEA/Cu NLs manifest two size h-dependent hardness regimes(i.e.,increased hardness at small h and hardness plateau at large h),while the He-implanted ones exhibit monotonically increased hardness.Contrary to the fashion that smaller h renders less irradiation hardening in bimetal NLs,the Fe_(50)Mn_(30)Co_(10)Cr_(10)/Cu NLs manifest the trend that smaller h leads to greater irradiation hard-ening.By contrast,the Fe_(50)Mn_(30)Co_(10)Ni_(10)/Cu NLs exhibit the maximum irradiation hardening at a critical h=50 nm.Below this critical size,smaller h results in lower radiation hardening(similar to bimetal NLs),while above this size,smaller h results in greater radiation hardening(similar to Fe_(50)Mn_(30)Co_(10)Cr_(10)/Cu NLs).Moreover,these transformable HEA/Cu NLs display inverse h-dependent strain rate sensitivity(SRS m)before and after He-ion irradiation.Nevertheless,compared with as-deposited samples,the irradi-ated Fe_(50)Mn_(30)Co_(10)Cr_(10)/Cu NLs display reduced SRS,while the irradiated Fe_(50)Mn_(30)Co_(10)Ni_(10)/Cu NLs dis-play enhanced SRS.Such unusual size-dependent irradiation strengthening and inverse h effect on SRS in irradiated samples were rationalized by considering the blocking effects of He bubbles on dislocation nucleation and motion,i.e.,dislocations shearing or bypassing He bubbles.

核电厂放射性废树脂处理技术研究

在对放射性废树脂进行处理的过程中,由于反应环境的稳定性难以得到保障,导致废树脂中核素衰变时刻放射性活度速率较慢,为此,提出核电厂放射性废树脂处理技术研究。在废树脂容器材料选择阶段,充分考虑了辐照敏感性和清洁解控下的处理要求,将C15混凝土作为最终的容器材料,并对具体的材料配比进行设计。在处理工艺流程设计阶段,采用了烘干封装形式的HIC放射性废树脂处理方式,定量化地在锥形干燥器中对放射性废树脂进行干燥处理,将蒸发的气态物转入至放射性废液处理系统,将烘干废物移送至HIC封装工位实施二次包装处理。并根据核素检测结果,确定出厂时间。在测试结果中,设计处理技术下,废树脂核素衰变时刻放射性活度在短时间内实现了快速下降,与对照组相比具有明显优势。

离体培养条件对百合鳞片辐射敏感性的影响

研究了辐射处理主因素及其与培养基成分、外植体类型的交互作用对东方百合鳞片辐射敏感性的影响。结果表明:在试验辐射剂量范围内,离体培养约6d的百合鳞片经60Coγ射线辐照后存活率随剂量增大而呈现下降趋势;辐射处理对百合鳞片的出芽率和出芽数有强烈的抑制作用。在芽诱导阶段,培养基成分在一定程度上影响鳞片的辐射敏感性;鳞片辐射敏感性随培养时间增加而减弱;外部鳞片与中部鳞片表现的辐射敏感性基本一致。

紫外降解双酚A的因素敏感性分析及机理探讨

以光强(A)、双酚A的初始浓度(B)、pH(C)及转速(D)为变量,设计了4因素4水平的正交试验L_(16)(4~4)以考察水溶液中双酚A紫外降解的因素敏感情况,并初步探讨了其降解机理。实验结果表明,在所研究的范围内,各因素对双酚A紫外降解的敏感程度排序为:A>B>C>D;其中,光强与双酚A的初始浓度对污染物的降解速率的影响非常显著(p<0.05),而pH与转速几乎不产生影响(p>0.05)。以高效液相色谱的谱图为基础,水溶液中双酚A紫外光解的路径受反应条件特别是溶液pH值的影响。碱性条件下(pH=11)以离子形态存在的双酚A与水溶液光解产生的自由基结合形成·OH-双酚A并进一步发生取代或开环反应,酸性或中性条件下双酚A在自由基作用的情况下分解生成苯酚(t_r=4.516 min);并通过标准物质定性推断了可能的中间产物。

面包中耐辐射菌种的鉴定及其敏感性研究

本研究采用传统的分离方法对辐照面包中主要微生物菌群进行分离,并根据生理生化特性和对API鉴定系统中碳水化合物的利用情况将分离出的两种耐辐射菌种进行鉴定,进而采用感染实验研究以面包为生长介质两种耐辐射菌对辐照处理的敏感性。结果显示,枯草芽孢菌和克氏微球菌是面包上分离鉴定得到的耐辐射菌种。同时辐照剂量与各菌种存活菌数之间存在明显的线性关系,高、低两个浓度枯草芽孢杆菌的D10值分别为0.758kGy、0.871kGy;高、低两个浓度克氏微球菌的D10值分别为0.720kGy、0.823kGy,可见枯草芽孢杆菌较克氏微球菌对射线更加不敏感。

柑桔大实蝇辐照成虫对两种引诱剂的敏感性

为了明确柑桔大实蝇Bactrocera minax(Enderlein)辐照成虫和田间自然发生的成虫对引诱剂的敏感性差异,指导柑桔大实蝇辐照不育技术的有效利用,在田间释放柑桔大实蝇辐照成虫,以常用引诱剂桔丰和果瑞特同期进行诱集监测。监测结果显示,辐照显著降低了柑桔大实蝇成虫对桔丰和果瑞特的敏感性。在柑桔大实蝇成虫发生高峰期桔丰诱集到辐照成虫的数量仅为诱集总虫量的2.6%-11.6%,果瑞特为5.0%-50.0%;桔丰诱集到的辐照雌性成虫的数量仅为诱集的所有雌性成虫数量的4.4%-11.8%,果瑞特为33.7%-50.0%;桔丰诱集到的辐照雄性成虫的数量仅为诱集的所有雄性成虫的5.3%-11.4%,而果瑞特始终未能诱集到辐照雄性成虫。此外,辐照缩短了柑桔大实蝇成虫对常用引诱剂趋向性的持续时间。研究结果对柑桔大实蝇辐照不育技术与诱集诱杀技术的协调应用具有重要指导意义。

辐射法制备壳聚糖/聚丙烯酸水凝胶及其溶胀性能研究

采用电子束对壳聚糖和丙烯酸混合水溶液进行辐照,制得了壳聚糖/聚丙烯酸(CS/PAAc)共聚物水凝胶。研究了pH值、各组分配比和辐照剂量等因素对产物溶胀率的影响。结果表明,水凝胶具有pH敏感性,在强酸性(pH≈1)和碱性(pH>7)条件下均表现出较好的溶胀性;而在pH2—5范围内溶胀率较小。同时,随着辐照剂量的增大,产物的溶胀率也随之增大,在酸性条件下表现并不明显,而当pH>6时增大效果较显著。

辐射制备热敏性水凝胶及控制释放

通过在空气中预辐射聚丙烯多孔膜，将单体N－异丙基丙烯酸胺（NIPAAm）接枝到聚丙烯多孔膜的表面上，得到一种新型的具有良好的热敏性及机械性能的水凝胶。研究了各种因素对接枝反应的影响，考察了其热敏性能及表面形貌，通过改变温度可改变多孔膜孔径大小，并将其用于托马斯亮蓝分子的渗透及控释过程。

硅橡胶膜上NIPAAm预辐射接枝机理研究

采 用预辐射 方式将 Ｎ Ｉ Ｐ Ａ Ａｍ 接枝到 硅橡胶上 ，结果表 明：接枝反 应 是由 样品 在空 气中辐照生 成的过 氧化物（ 主 要是氢 过氧化物） 引发的 ，并且仅 在较 高温 度下 接枝 才能 进行。 研究 了过氧化物 的产生 和分解，计 算出过 氧化物分 解的活 化能为２７ ２ｋ Ｊ／ ｍ ｏｌ 。 通过 对接 枝反 应动 力学 的研究表明 ，接枝反 应的活化 能较低 ，约５４７ ｋ Ｊ／ ｍ ｏｌ 。讨 论了接枝 反应机理 。