1例急性铀中毒案例的33年医学随访

本文报道对1例硝酸铀酰复合烧伤致急性铀中毒案例进行了33年的医学随访,以观察和研究人体急性铀中毒后的远期效应。随访期间研究观察的内容：①主诉症状和其尿铀检测;②临床实验室检查：外周血像及骨髓像,肾功能,肝功能,对细胞遗传学的影响,用放免分析方法检测甲状腺、肾上腺的内分泌功能,免疫功能检查包括细胞免疫功能和体液免疫功能,代谢功能检查包括糖耐量试验、胰岛素释放试验、脂代谢,细胞化学检查包括淋巴细胞糖元和粒细胞碱性磷酸酶,神经系统损伤效应,心肺等功能检查;③L的生育能力和遗传效应,及对其子女的随访。结果表明：外周血及骨髓功能正常;肾功能基本恢复;肝功能正常;淋巴细胞染色体畸变率检有染色体型畸变和染色单体畸变;细胞遗传学检查有环状体、双着丝粒体及断片等染色体型畸变,还有以单体断片和碎片为主的染色单体畸变;其他检查如甲状腺、肾上腺内分泌功能,细胞和体液免疫功能,代谢功能检查、淋巴细胞糖元和粒细胞碱磷酶检查基本正常;生育能力未受影响,子女体质差,疾病易感性高、抗病毒能力差;儿子不育,女儿妊娠期胎儿发育不良。     

显像管发射小的跟踪分析

本文对黑白显像管发射小进行了跟踪分析，认为阴极涂层脱落和管内真空度不良是导致显像管发射小的主要原因。     

Contamination of shellfish from Shanghai seafood markets with paralytic shellfish poisoning and diarrhetic shellfish poisoning toxins determined by mouse bioassay and HPLC

This paper reports the results of investigations of shellfish toxin contamination of products obtained from Shanghai seafood markets. From May to October 2003, 66 samples were collected from several major seafood markets. Paralytic shellfish poisoning (PSP) and diarrhetic shellfish poisoning (DSP) toxins in shellfish samples were monitored primarily by a mouse bioassay, then analysed by HPLC for the chemical contents of the toxins. According to the mouse bioassay, eight samples were detected to be contaminated by PSP toxins and seven samples were contaminated by DSP toxins. Subsequent HPLC analysis indicated that the concentrations of the PSP toxins ranged from 0.2 to 1.9 µg/100 g tissues and the main components were gonyautoxins 2/3 (GTX2/3). As for DSP, okadaic acid was detected in three samples, and its concentration ranged from 3.2 to 17.5 µg/100 g tissues. Beside okadaic acid, its analogues, dinophysistoxins (DTX1), were found in one sample. According to the results, gastropod (Neverita didyma) and scallop (Argopecten irradians) were more likely contaminated with PSP and DSP toxins, and most of the contaminated samples were collected from Tongchuan and Fuxi markets. In addition, the contaminated samples were always found in May, June and July. Therefore, consumers should be cautious about eating the potential toxic shellfish during this specific period.     

Influence of ammonia on the conductivity of Nafion membranes

The effect of NH₃ and NH₄⁺ poisoning on the conductivity of Nafion membranes was investigated via electrochemical impedance spectroscopy. The conductivities of membranes prepared with different NH₄⁺ compositions were measured in deionized water at room temperature and compared to those at 80 °C in a gas phase for various relative humidities. The liquid-phase conductivity decreased linearly with an increase in the NH₄⁺ composition in the membrane (y_NH4⁺), with that of the NH₄⁺-form having a conductivity 25% that of the H⁺-form. The gas-phase conductivity of the NH₄⁺-form, on the other hand, declined by 66–98% relative to the H⁺-form depending on humidity. The conductivities of fresh membranes in the presence of gas-phase NH₃ at different humidities were also studied. The conductivity decreased with time-on-stream and reached the same conductivity at a given humidity regardless of the NH₃ concentration, but the time to reach steady-state varied with NH₃ concentration. The y_NH4⁺ at steady-state conductivity was equivalent for all the NH₃ concentrations studied. The kinetics of conductivity decrease was slower at higher humidities. The humidity and y_NH4⁺ appear to have a concerted effect on the conductivity. The quantitative conductivity data under practical fuel cell conditions should be useful for future fuel cell modeling.     

A medium entropy cathode with enhanced chromium resistance for solid oxide fuel cells

Perovskite type SrCo_0.9Ta_0.1O_3-δ (SCT91) cathode exhibits high activity for oxygen reduction reactions, but the instability in Cr-containing atmosphere restricts its application in intermediate temperature solid oxide fuel cells (IT-SOFCs). In this study, a B-site medium-entropy SrCo_0.5Fe_0.2Ti_0.1Ta_0.1Nb_0.1O_3-δ (SCFTTN52111) cathode is proposed and investigated as a potential Cr-tolerance cathode. The electrochemical activity of pristine SCT91 cathode degrades rapidly in the presence of volatile chromium species. In contrast, SCFTTN52111 performs very stable. Chromium vapors prefer to react with segregated SrO species rather than Co₃O₄ precipitates_. Significant secondary phases of SrCrO₄ and Co₃O₄ are detected on SCT91 electrode, while only trace by-products are found on medium-entropy cathode. The better Cr tolerance is closely related to the enhanced structural stability by medium-entropy engineering and reduced surface Sr segregations. This work sheds light on the development of robust cathodes for IT-SOFCs through rational design of configuration entropy.     

Characterization and performance of (La,Ba)(Co,Fe)O3 cathode for solid oxide fuel cells with iron–chromium metallic interconnect

(La_0.6Ba_0.4)(Co_0.2Fe_0.8)O₃ (LBCF) is synthesized by a sol–gel method as a Cr-tolerant cathode for intermediate-temperature solid oxide fuel cells (ITSOFCs). The electrochemical performance and Cr deposition process for the O₂ reduction reaction on LBCF cathodes in the presence and absence of a Fe–Cr alloy interconnect are investigated in detail, in comparison with a (La,Sr)(Co,Fe)O₃ (LSCF) electrode. Cr deposition occurs for the O₂ reduction reaction on LBCF electrodes in the presence of Fe–Cr alloy. Very different from that observed for the reaction on the LSCF cathode, Cr deposition on the LBCF electrode/gadolinia-doped ceria (GDC) electrolyte system is very small and shows little poisoning effect for O₂ reduction on LBCF electrode. The results demonstrate that the LBCF electrode has a high resistance towards Cr deposition and high tolerance towards Cr poisoning.     

连续重整PS-Ⅵ催化剂硫中毒分析及对策

福建联合石油化工股份有限公司芳烃联合装置重整单元采用UOP公司开发的第三代低压连续重整及再生技术,设计规模为1.4 Mt/a。装置在检修开工过程中由于预加氢汽提塔(C101)液位不准,造成淹塔,丧失分离效果。大量高硫、高水石脑油进入重整反应系统,造成重整催化剂严重硫中毒,测得重整循环氢中H2S质量浓度最高达56 mg/L。发现硫中毒后,首先稳定C101操作,校准C101液位计,保证重整进料合格;然后增加重整注氯,抑制硫的可逆吸附;通过低负荷热氢脱硫、催化剂循环热氢脱硫后将循环氢中H2S质量浓度降至4 mg/L;最后通过启动再生器烧焦,以低负荷再生烧焦循环脱硫的手段进行处理。在硫中毒17 d后,循环氢中H2S质量浓度降至小于0.5mg/L的正常水平,基本恢复了催化剂活性。     

重金属中毒对裂化催化剂反应性能影响的关联

利用催化裂化反应试验数据，经参数估计建立了转化率、焦炭产率和氢气产率与催化剂重金属含量的关联模型。统计检验结果表明，所建３个模型均具有较高的计算精度。研究结果表明，与钒相比，镍对焦炭产率和氢气产率影响较大，对转化率影响较小；随着催化剂重金属沉积量的提高，氢气产率不断提高，焦炭产率提高幅度呈先较大后较小的变化规律，而反应转化率呈先有所提高然后降低的变化规律。     

COS和H_2S毒化F-T合成催化剂热力学分析

利用热力学基础数据和相关软件对F-T合成催化剂COS和H_2S中毒的热力学进行了计算。在热力学上,Ru、Fe、Co的COS中毒在F-T合成反应可以发生的条件下均是自发过程。F-T合成反应体系中10~(-9)级的COS即可使Ru基催化剂中的金属Ru生成RuS_2而中毒。Fe和Co毒化后生成的硫化物种类较多,对这些反应的热力学计算结果表明,对于不同的反应,其平衡常数的差异很大,对应中毒反应发生时,所需的COS和H_2S的浓度也不同,对COS的要求更为严格。由于Fe基F-T合成催化剂活性相的复杂性,利用对催化剂相关性质的修饰开发具有一定抗硫性的铁基F-T合成催化剂是可行的;对于Co催化剂,利用F-T合成的反应特点和催化剂改性开发具有一定抗硫性催化剂是可能的。