Te溶剂Bridgman法CdMnTe晶体核辐射探测器的制备和表征

碲锰镉(CdMnTe)作为性能优异的室温核辐射探测器材料,可用于环境监测和工业无损检测领域。本文中采用Te溶剂Bridgman法生长In掺杂Cd_0.9Mn_0.1Te晶体,制备成10 mm×10 mm×2 mm大小的室温单平面探测器,研究了该探测器对²⁴¹Am@59.5 keV γ射线源的能谱响应。通过表征红外透过率、电阻率以及探测器能谱响应等参数,综合评定了探测器用CdMnTe晶体的质量、电学和探测器性能。结果表明,晶片的红外透过率均在55%以上,最好可达到60%。采用湿法钝化,100 V偏压下的漏电流由钝化前的9.48 nA降为钝化后的7.90 nA,钝化后的电阻率为2.832×10¹⁰ Ω·cm。在-400 V反向偏压下,CdMnTe探测器对²⁴¹Am@59.5 keV γ射线源的能量分辨率在钝化前后分别为13.53%和12.51%,钝化后的电子迁移率寿命积为1.049×10^-3 cm²/V。研究了探测器的能量分辨率随电压的变化特性,当偏压≤400 V时,探测器的能量分辨率主要由载流子的收集效率决定,而当偏压>400 V时,能量分辨率由漏电流决定。本文研究结果表明,Te溶剂Bridgman法生长的CdMnTe晶体质量较好,电阻率和电子迁移率寿命积满足探测器制备需求。     

导电聚苯胺线膜修饰ZnO纳米棒阵列的可控制备及其紫外探测性能

基于p-n结的光生伏特效应可构筑性能优异的UV探测器,本文采用水热法可控制备竖直排列的氧化锌纳米棒阵列(n型ZnO-NRs),利用原位聚合法在ZnO-NRs表面上修饰p型聚苯胺线膜(PANI-NWs),再组装成ZnO-NRs与ZnO-NRs/PANI-NWs紫外探测器.通过扫描电镜(SEM)、X射线衍射仪(XRD)、紫...     

DMF体系中Cu2O球晶的制备及形貌分析

以N,N-二甲基甲酰胺(DMF)为溶剂,通过改变铜源和表面活性剂,调控反应参数,溶剂热条件下制备了三维十字形、空心及实心的Cu₂O球晶。利用XRD、SEM等表征手段,分析探讨了工艺条件变化对Cu₂O球晶形貌的影响。研究表明,随着DMF浓度的增大,体系的还原能力增强,Cu⁺增多,溶液的过饱和度增大,Cu₂O晶体集合体形态由晶体结构控制的各向异性与对称性的球晶逐渐向各向同性球晶演变。十二烷基硫酸钠(SDS)、十六烷基三甲基溴化铵(CTAB)、聚乙烯吡咯烷酮(PVP)等表面活性剂有助于降低溶液的过饱和度,增加结晶质的表面扩散能力,有利于规则形态Cu₂O晶粒的形成。反应体系中,Cu(Ac)₂·H₂O水解生成的羧基与DMF中的甲酰基在高温下发生脱羧反应产生CO₂气体以及SDS发泡作用产生的气体是形成空心Cu₂O球晶的重要原因。     

ZnO超细纳米线阵列的制备及其电化学性能

以Zn(NO₃)₂· 6H₂O和C₆H₁₂N₄为原材料,采用二步水热法在碳纤维布上合成了形貌尺寸均匀的ZnO超细纳米线阵列。用 X 射线衍射(XRD)和扫描电镜(SEM)对其晶体结构和形貌进行了表征,利用恒流充放电测试等手段对其进行电化学性能测试。测试结果表明,材料表现出优异的电化学性能。在200 mA/g的电流密度下循环150次后,ZnO超细纳米线阵列仍然约有730 mAh/g的充放电比容量,库伦效率保持在95%以上。在1 200 mA/g的大倍率条件下,材料的充放电比容量依旧可达481 mAh/g左右,表现出十分良好的循环稳定性和可逆性能,是一种较为理想的锂离子电池负极复合材料。     

Effect of Wearing Surgical Face Masks on Gas Detection from Respiration Using Photoacoustic Spectroscopy

Wearing surgical face masks is among the measures taken to mitigate coronavirus disease (COVID-19) transmission and deaths. Lately, concern was expressed about the possibility that gases from respiration could build up in the mask over time, causing medical issues related to the respiratory system. In this research study, the carbon dioxide concentration and ethylene in the breathing zone were measured before and immediately after wearing surgical face masks using the photoacoustic spectroscopy method. From the determinations of this study, the C₂H₄ was established to be increased by 1.5% after one hour of wearing the surgical face mask, while CO₂ was established to be at a higher concentration of 1.2% after one hour of wearing the surgical face mask, when the values were correlated with the baseline (control).     

Effect of Soaking Conditions and Fuzzy Analytical Method for Producing the Quick-Cooking Black Jasmine Rice

The quick-cooking rice product is an interesting product for the market which is easy to cook, with good sensorial qualities and health benefits. This work aimed to study the effect of the soaking conditions, namely baking powder concentration (0.1, 0.2, or 0.3%), soaking temperature (room temperature, 50 or 60 °C), and soaking time (10, 20, or 30 min), in order to improve the physical properties and also the sensory characteristics, with high bioactive compound content, of Quick-Cooking Black Jasmine Rice (QBJR). The physical properties of the final product, namely the rehydration capacity, morphology, and texture, were observed. Moreover, the total phenolic, total flavonoid, and total anthocyanin were determined. The results showed that the samples with a high baking powder concentrations soaked at high temperatures for longer time affect the low rehydration capacity with a high hardness value and a decreased bioactive compound content. In addition, the sensory score including softener, flavor, and overall acceptance were lower score. Moreover, to determine the best soaking condition with complex data, the Fuzzy Analytical Method (FAM) was performed by an online FAM program. The results showed that soaking at room temperature for 30 min in 0.1% of baking powder showed the highest overall performance index of 6.52.     

ZnSe薄膜的化学反应辅助热壁外延法生长及特性研究

本文通过将新型化学气相反应促进剂Zn(NH4)3Cl5引入到热壁外延系统中,以二元素单质Zn和Se为原料,直接在Si(111)衬底上生长了高质量的ZnSe晶体薄膜,薄膜成分接近理想化学计量比。研究了主要工艺参数对薄膜生长形貌和性能的影响。采用SEM、AFM、EDS和PL谱技术研究了生长的ZnSe薄膜的形貌、成分和发光特性。研究结果表明,热壁温度和生长时间是影响ZnSe薄膜形貌的主要因素;气相反应促进剂在薄膜生长和调节成分方面扮演了关键角色,Zn(NH4)3Cl5的存在使得Zn(g)和Se2(g)合成ZnSe晶体的反应转变为气固非一致反应,从而更容易获得近乎理想化学计量比的ZnSe薄膜。ZnSe薄膜在氦镉激光激发下,室温下PL谱由近带边发射和(VZn-ClSe)组合的SA发光组成,而在飞秒激光激发下,仅在481nm处显示出强烈的双光子发射峰。     

Er3+:NaY(Wo.9Moo.1O4)2晶体的生长及光谱性能

采用提拉法(CZ法),生长出质量良好的Er3+:NaY(W0.9Mo0.1O4)2晶体.通过X射线粉末衍射,红外光谱分析,并与NaY(WO4)2相比较,得到Er3+:NaY(W0.9Mo0.1O4)2晶体的结构与NYW类似,仍为四方晶系的白钨矿结构,I4(1)/α空间群.测定了晶体的实际组成,得到晶体中各元素均按理论值进行掺杂,计算了掺杂离子的分凝系数约为1.15.在光谱性质上,测试了晶体的吸收光谱,及晶体在50～1000cm-1波数范围内的拉曼光谱,并计算了各吸收峰的半峰宽及吸收系数A.     

The Optimal Error Estimate of the Fully Discrete Locally Stabilized Finite Volume Method for the Non-Stationary Navier-Stokes Problem

This paper proves the optimal estimations of a low-order spatial-temporal fully discrete method for the non-stationary Navier-Stokes Problem. In this paper, the semi-implicit scheme based on Euler method is adopted for time discretization, while the special finite volume scheme is adopted for space discretization. Specifically, the spatial discretization adopts the traditional triangle P1−P0 trial function pair, combined with macro element form to ensure local stability. The theoretical analysis results show that under certain conditions, the full discretization proposed here has the characteristics of local stability, and we can indeed obtain the optimal theoretic and numerical order error estimation of velocity and pressure. This helps to enrich the corresponding theoretical results.     

A Specific HPLC Method to Determine Residual HEPES in [68Ga]Ga-Radiopharmaceuticals: Development and Validation

Background: Nowadays, in Nuclear Medicine, clinically applied radiopharmaceuticals must meet quality release criteria such as high radiochemical purity and radiochemical yield. Many radiopharmaceuticals do not have marketing authorization and have no dedicated monograph within European Pharmacopeia (Ph. Eur.); therefore, general monographs on quality controls (QCs) have to be applied for clinical application. These criteria require standardization and validation in labeling and preparation, including quality controls measurements, according to well defined standard operation procedures. However, QC measurements are often based on detection techniques that are specific to a certain chromatographic system. Several radiosyntheses of [⁶⁸Ga]Ga-radiopharmaceuticals are more efficient and robust when they are performed with 2-[4-(2-hydroxyethyl)piperazin-1-yl] ethanesulfonic acid (HEPES) buffer, which is considered as an impurity to be assessed in the QC procedure, prior to clinical use. Thus, Ph. Eur. has introduced a thin-layer chromatography (TLC) method to quantify the HEPES amount that is present in [⁶⁸Ga]Ga-radiopharmaceuticals. However, this is only qualitative and has proven to be unreliable. Here we develop and validate a new high-performance liquid chromatography (UV-Radio-HPLC) method to quantify the residual amount of HEPES in ⁶⁸Ga-based radiopharmaceuticals. Method: To validate the proposed UV-Radio-HPLC method, a stepwise approach was used, as defined in the guidance document that was adopted by the European Medicines Agency (CMP/ICH/381/95 2014). The assessed parameters are specificity, linearity, precision (repeatability), accuracy, and limit of quantification. A range of concentrations of HEPES (100, 80, 60, 40, 20, 10, 5, 3 μg/mL) were analyzed. Moreover, to test the validity and pertinence of our new HPLC method, we analyzed samples of [⁶⁸Ga]Ga-DOTATOC; [⁶⁸Ga]Ga-PSMA; [⁶⁸Ga]Ga-DOTATATE; [⁶⁸Ga]Ga-Pentixafor; and [⁶⁸Ga]Ga-NODAGA-Exendin-4 from different batches that were prepared for clinical use. Results: In the assessed samples, HEPES could not be detected by the TLC method that was described in Ph. Eur. within 4 min incubation in an iodine-saturated chamber. Our developed HPLC method showed excellent linearity between 3 and 100 μg/mL for HEPES, with a correlation coefficient (R²) for calibration curves that was equal to 0.999, coefficients of variation (CV%) < 2%, and percent deviation value of bias from 100% to 5%, in accordance with acceptance criteria. The intra-day and inter-day precision of our method was statistically confirmed and the limit-of-quantification (LOQ) was 3 μg/mL, confirming the high sensitivity of the method. The amount of HEPES that was detected with our developed HPLC method in the tested [⁶⁸Ga]Ga-radiopharmaceuticals resulted well below the Ph. Eur. limit, especially for [⁶⁸Ga]Ga-NODAGA-Exendin-4. Conclusions: The TLC method that is described in Ph. Eur. to assess residual HEPES in [⁶⁸Ga]-based radiopharmaceuticals may not be sufficiently sensitive and thus unsuitable for QC release. Our new HPLC method was sensitive, quantitative, reproducible, and rapid for QCs, allowing us to exactly determine the residual HEPES amount in [⁶⁸Ga]Ga-radiopharmaceuticals for safe patient administration.