Assessment of creep-fatigue damage at main vessel triple point of Prototype Fast Breeder Reactor after core disruptive accident

The main vessel (MV) carries all the major reactor components including core and liquid sodium filled to 12.4 m height. The reactor core along with the inner vessel is placed on the grid plate, which is supported on the core support structure (CSS). The CSS is supported on the MV through a support shell, welded to the dished end at the point where crown and knuckle joins. The CSS support shell to MV joint is called as triple point and damage at this point is of concern. The core catcher (CC) is placed below the CSS and is also supported on the CSS support shell. The triple point is subjected to a dead load of 920 t. During the unlikely event of core disruptive accident (CDA) a high dynamic pressure will act on the core catcher (CC), which in turn exerts a high load on the triple point. Also the hot molten core debris will come to the CC, which is close to the MV dished end. This will result in increase of temperature in the cold pool, which will cause significant creep damage at triple point during post accident heat removal phase. As the triple point is the only junction, which is supporting the reactor core and CC through CSS support shell, its failure can cause serious consequences to the integrity of MV. Hence, triple point is analysed to ensure its integrity during the transient pressure loading and subsequent post accident heat removal (PAHR) phase of CDA. The stress intensities during transient pressure are found to be within the limits. The subsequent creep damage during post accident heat removal (PAHR) phase is also assessed. Based on the apportioned creep damage of 0.4 for category 4 events, the triple point can be kept at a temperature of 923 K (650°C) or 973 K (700°C) effectively for a period of 1.2 × 10⁴ h (500 days) or 662 h (27.6 days) respectively which are acceptable with comfortable margin. More details are presented in the paper.     

中国钠冷快堆材料研发体系的研究

钠冷快中子反应堆(SFR,简称快堆)是中国发展第4代先进核能系统的主力堆型,也是中国核能技术实现闭式燃料循环和可持续发展的重要战略选择。目前快堆大部分关键结构部件均采用国外进口材料,成为严重制约中国快堆事业发展的瓶颈。根据中国钠冷快堆技术工程化与商业化发展的总体布局,分析了当前快堆材料的实际发展状况和所面临的核心问题,探讨了快堆材料研发的重点任务,并提出了快堆材料研发体系建设的基本思路及应对措施。同时,拟定了解决相应问题的快堆材料技术发展路线图,以期为中国钠冷快堆技术的发展提供支撑和借鉴。     

A multiple discriminant analysis of vessel accidents

A large sample of 936 vessel accident cases occurring between 1979 and 1987 on the lower Mississippi River were cluster analyzed to generate four groups relatively unique in their respective attribute values. The attributes used to cluster the accidents included participation in the U.S. Coast Guard's New Orleans Vessel Traffic Service (NOLA-VTS), type of accident, river stage traffic level, system utilization, accident location, weather conditions, and time of accident. The four-group cluster solution resulted in logical groupings, given the realities of navigating the lower Mississippi River. The four groups resulting from the cluster analysis were characterized as Group 1: Danger Zone (224 cases), 100% NOLA-VTS participants whose accidents occurred primarily on the most dangerous part of the river; Group 2: Bad Conditions for Good Navigators (230 cases), characterized by a high rate of participation and unserious accidents occurring in treacherous navigating conditions; Group 3: Probably Preventable (134 cases), characterized by a low participation rates and serious accidents occurring in not the worst navigating conditions; and Group 4: Accidents That Should Not Have Happened (345 cases), characterized by zero participation and serious accidents occurring in reasonable navigating conditions. Significant marginal participation rates for the marine tracking technology across the four accident clusters (100% for Group 1, 67% for Group 2, 37% for Group 3, and 0% for Group 4) effectively distinguishes between casualty groups. In the subsequent discriminant analysis, three discriminant functions correctly classified 96% of the total accidents, including 100% of Group 1 and Group 4, 90% of Group 2, and 88% of Group 3. The variables contributing most to overall group differentiation were participation in the system, overall system utilization, river stage, traffic level, time and location of accidents. The three discriminant functions were statistically significant, with each individual function accounting for a large relative percentage of the variance between the groups. In order of decreasing discriminating power, the functions could be characterized as (1) System Participation and Utilization, (2) Navigating Conditions, and (3) Time and Place.     

Fast analysis of drugs in a single hair

A new method for the fast screening of cocaine and 6-monoacetylmorphine (6-MAM) in a single hair, using gas chromatography/mass spectrometry (GC/MS), is described. The analyses are conducted in less than 10 min with minimal sample preparation. The novel method combines the ChromatoProbe direct sample introduction device for intrainjector thermal extraction, fast GC separation, a supersonic molecular beam GC/MS interface and hyperthermal surface ionization (HSI). The technique has been successfully employed for the detection of cocaine in as little as a 1-mm section of hair using selected ion monitoring (SIM). Unambiguous full scan mass spectra of cocaine and 6-MAM were obtained on a single hair for cocaine and heroin users, respectively. HSI was found to be almost 3 orders of magnitude more selective than electron impact ionization for cocaine compared with the major hair constituents, with a minimum detected concentration of approximately 10 ppb in the SIM mode. Results obtained for 12 drugs users showed full qualitative agreement with similar results using rigorous solvent extraction followed by electrospray-liquid chromatography/mass spectrometry analysis. However, quantitative studies showed only partial agreement. No false positives were observed for 10 drugs free subjects. This method enables fast drug monitoring along the hair length which permits time correlation studies.     

Computer-assisted image analysis of intratumoral vessel density in mammary tumors from dogs

OBJECTIVE: To determine whether intratumoral microvessel density can be used to distinguish benign from malignant mammary tumors in dogs and to predict the outcome of surgical treatment for small volume (< 3-cm diameter) tumors. SAMPLE POPULATION: Tissue sections from 58 mammary tumors (42 malignant and 16 benign) from dogs. PROCEDURE: Mammary tumors were stained by immunohistochemistry for factor VIII-related antigen. Computer-assisted image analysis was used to determine intratumoral vessel density in immunostained areas. Total vascular density (TVD), calculated from 3 non-overlapping fields, was analyzed for correlation with patient or tumor histomorphologic characteristics, and results obtained by surgical treatment of small volume tumors. RESULTS: Mean TVD of malignant tumors was significantly greater than that of benign tumors. Total vascular density was not correlated with patient age, sex, reproductive status, clinical tumor stage, or histologic type. For small volume (< 3-cm diameter) malignant tumors, mean TVD was higher in tumors that recurred after surgery than in tumors that did not recur; however, TVD was not predictive of time to recurrence. CONCLUSION AND CLINICAL IMPLICATIONS: Immunohistochemistry and computer-assisted image analysis allowed objective quantitation of intratumoral microvessel density in formalin-fixed, paraffin-embedded tissue sections. Tumors with high TVD were more likely to recur after surgical treatment than tumors with low TVD suggesting that TVD measurements can be used by the clinician, in addition to histologic type and clinical stage, to predict prognosis after surgical treatment. These data also provide rationale for use of antiangiogenesis strategies for treatment of malignant mammary tumors in dogs.     

维氏硬度试验及其主要影响因素分析

维氏硬度试验是静态硬度试验中最精确的一种试验方法，但在实际操作中易受到多种因素的影响。对维氏硬度试验的主要影响因素进行了分析，研究这些因素对维氏硬度值的影响变化。以此说明，检验人员在试验操作中要严格按照标准规定的方法执行，降低测量误差。     

A new approach to the analysis of vessel residence time distribution curves

Mathematical models for the evaluation of residence time distribution (RTD) curves on a large variety of vessels are presented. These models have been constructed by combination of different tanks or volumes. In order to obtain a good representation of RTD curves, a new volume (called convection diffusion volume) is introduced. The convection-diffusion volume allows the approximation of different experimental or numerical RTD curves with very simple models. An algorithm has been developed to calculate the parameters of the models for any given set of RTD curve experimental points. Validation of the models is carried out by comparison with experimental RTD curves taken from the literature and with a numerical RTD curve obtained by three-dimensional simulation of the flow inside a tundish.     

RH真空循环脱气装置水模型循环流量的实验分析

循环流量是判断RH真空脱气装置冶炼效率的最重要的指标之一。本文中采取了两种方法－－超声波流量计法和粒子示踪法对RH真空脱气装置的水模型的循环流量进行测量分析，同时也研究了新型的多管RH装置的循环流动，比较新型装置同传统装置的循环流动的差别。结果表明：利用超声波流量计和粒子示踪法两种方法测量的结果都显示新型多管RH真空脱气装置循环流量大于传统的两管RH装置循环流量，并且，随着喷入气体量的增加，新装置循环流量的增加幅度也大于传统装置的增加幅度。     

HP295钢中非金属夹杂物形成的热力学分析

针对HP295钢,采用热力学计算预测了冶炼和凝固过程中夹杂物的组成,同时,用扫描电镜（SEM）及能谱仪（EDS）对夹杂物的形貌和成分进行分析．结果表明：采用硅锰脱氧时,钢液中形成的夹杂物主要为鳞石英（SiO2）、锰铝榴石（3MnO·Al2O3·3SiO2）、莫来石（3Al2O3·2SiO2）和刚玉（A1203）等4类,且随【Al】含量提高或[01含量降低,夹杂物逐渐从鳞石英为主向刚玉为主转变,[A1]〈1×10^-6时主要为鳞石英,a[O]〈3×10^-3时则以刚玉为主;凝固过程析出夹杂物的组成与[Al]、[O]含量有关,1550℃时,当n[O]〉115．6×10^-5及[A1]〈4．5×10^-6时析出鳞石英,当口【O】〈115．6×10^5及[A1]〈10．5×10^-6时析出莫来石,当[A1]〉10．5×10^-6时析出刚玉;1510℃时,当a[01〉75．2×10^-5及[Al]〈3．51×10^-6时析出鳞石英,a[O]〈75．2×10^-5及[A1]〈8．18×10^-6时析出莫来石,[A1]〉8．18×10^-6时析出刚玉;另外,当3钢中有[Ca]存在时,凝固时可能析出钙斜长石甚至假硅灰石,析出物的成分及数量与钙的活度有关．热力学计算预测结果与扫描电镜分析结果基本一致,表明该热力学计算方法是可行的．     

440MVA主变压器出线故障分析及改进对策

介绍了宝钢电厂4号机组440 MVA/110 kV主变压器高压出线发生的故障情况,经检查分析,确认故障原因是由于高压出线连接点接触电阻过大导致过热。暴露了设备制造厂在设计制造质量方面存在的问题,连接件加工不良、缺乏验证和试验是出现质量问题的主要原因;提出并实施改进了连接接头的型式、增加导线截面积、增加散热面的措施。通过两年运行后的检查,验证了对策的有效性,确保了设备稳定安全运行,同时为变压器制造厂的设计改进提供了宝贵的经验。     

Flow cytometric analysis of platelet activation by different collagen types present in the vessel wall

The interaction of platelets with collagens of the vessel wall is a critical event in primary haemostasis. Although numerous studies have examined the ability of various collagen types to support platelet adhesion, little is known concerning the relative ability of different collagens to elicit specific activation markers in platelets. In this report, flow cytometric analysis has been utilized to evaluate the ability of various native collagen types to elicit secondary activation events in human platelets. Collagen types I, III, V and VI induced alpha-granule secretion and up-regulation of cell surface glycoprotein (GP) IIb/IIIa. In contrast, collagen type IV did not elicit these responses in the concentration ranges examined. Dose-response curves for alpha-granule secretion induced by the various collagen types indicated that human type III and human type I collagens were less effective than human type V, human type VI and calf skin type I. In addition, the ability of these various collagens to activate GPIIb/IIIa to its ligand binding conformation was even more heterogenous with only human type VI and calf skin type I readily promoting this transition. These data demonstrate that flow cytometric analysis of collagen-induced platelet activation is feasible and that collagen-mediated alpha-granule secretion and membrane glycoprotein redistribution in human platelets are separate events from activation of GPIIb/IIIa.     

Dynamic Load Simulator: Development of a Prototype

This technical note describes prototype development of a next generation of structural testing facility referred to here as a dynamic load simulator (DLS). The DLS simulates dynamic loading environment such as wind, waves, or earthquake effects, utilizing an electric or hydraulic actuator system instead of conventional facilities such as a wind tunnel, wave tank, or shaking table. Similitude requirements or the system capacity often preclude testing of large-scale models utilizing these facilities. In conventional test facilities continuous space-time variations of aerodynamic and hydrodynamic pressure fields and inertial loads are introduced to model the effects of wind, waves, or earthquakes. On the other hand, DLS provides discrete point loads utilizing a single- or multiactuator system to produce global dynamic load characteristics by taking into account the overall spatiotemporal correlation. A suite of typical loading protocols that includes sinusoidal, random correlated Gaussian, and non-Gaussian variations are simulated and verified experimentally utilizing single and dual actuator systems.     

ORACLE数据库实现的原型法设计

ORACLE数据库，采用了第四代语言SQL，并用C作为它的开发语言，所以它不仅速度快使用方便；而且可移植性兼容性极好，可以运行于各类微型机、小型机和大型机上；加之它较强网络系统的支持和开放性，在我国已得到了广泛的应用．以其金矿备件管理系统为例，说明用ORACLE数据库实现快速原型法设计的特点及其优越性．     

轧机主传动电机励磁控制分析

在技术资料短缺的情况下，结合实际经验，绘制出进口轧机主传动电机励磁控制电路图，并进行了较为详细的分析。     

Fast high-performance liquid chromatographic analysis of naphthodianthrones and phloroglucinols from Hypericum perforatum extracts

Hypericum perforatum L. (St. John's Wort) has been used in modern medicine for treatments of depression and neuralgic disorders. An HPLC method with photodiode array detection for the rapid determination of the major active compounds, naphthodianthrones and phloroglucinols, has been developed. The method permits the determination of hypericin, protohypericin, pseudohypericin, protopseudohypericin, hyperforin and adhyperforin in an extract in less than 5 min. Good linearity over the range 0.5-200 microg/mL for hyperforin and 0.02-100 microg/mL for hypericin was observed. Intra-assay accuracy and precision varied from 0.1 to 17% within these ranges. Lower levels of quantitative determination were 2 microg/mL for hyperforin and 0.5 microg/mL for hypericin, while detection limits were 0.1 and 0.02 microg/mL, respectively.     

The validity of the California Q-set Alexithymia Prototype

Classic antihistamines, namely diphenhydramine, chlorpheniramine, clemastine, perphenazine, hydroxyzine, and tripelennamine, share structural features with substrates and inhibitors of the polymorphic cytochrome P450 (CYP) isozyme CYP2D6. Therefore, the current study was undertaken to characterize the in vitro inhibition of CYP2D6 by these commonly used, histamine H1 receptor antagonists. Microsomal incubations were performed using bufuralol as a specific CYP2D6 substrate and microsomes derived from human cells transfected with CYP2D6 cDNA. Reaction velocities were assessed in the absence and presence of antihistamines (20 microM) at 11 substrate concentrations (1, 2.5, 5, 7.5, 10, 15, 20, 25, 50, 75, and 100 microM), as well as at three nonsaturating substrate concentrations (2.5, 5, and 20 microM) and three inhibitor concentrations (5, 20, and 50 microM). In the presence of all antihistamines, the Vmax and KM of bufuralol 1'-hydroxylation were significantly altered, compared with the uninhibited reaction (p < 0.05). Lineweaver-Burke plots suggested competitive inhibition of the reaction by diphenhydramine and mixed inhibition by all other antihistamines tested. Diphenhydramine and chlorpheniramine, with estimated Ki values of approximately 11 microM, were the weakest inhibitors of CYP2D6 in vitro. Whereas tripelennamine, promethazine, and hydroxyzine were similar in their inhibitory capacities (Ki approximately 4-6 microM), clemastine appeared to be significantly more potent, with a Ki of approximately 2 microM. These data demonstrate that classic histamine H1 receptor antagonists, available in over-the-counter preparations, inhibit CYP2D6 in vitro. Furthermore, the CYP2D6-inhibitory concentrations of these antihistamines are in the range of their expected hepatic blood concentrations, suggesting that, under specific circumstances, clinically relevant interactions between classic antihistamines and CYP2D6 substrates might occur.