High-temperature creep of single-crystal nickel-based superalloy: microstructural changes and effects of thermal cycling

Creep tests were performed on MC2 single crystal superalloy at 950°C/200?MPa and 1150°C/80?MPa under isothermal and thermal cycling conditions with a tensile axis along the [0?0?1] direction. It was found that the thermal cycles strongly affect the creep behavior at 1150°C but not at 950°C. This was related to the repetitive precipitation and dissolution of small γ′ rafts at the higher temperature, as revealed by quantitative characterization of the γ/γ′ microstructure. The dislocation microstructure exhibits similar trends in all the tested conditions, with a very high activity of a[1?0?0]-type dislocations climbing through the rafts. Such climbing dislocations constitute a recovery process for the deformation active system. It appears that the density of a[1?0?0] dislocations, and not their climb velocity or diffusion rate, is the key parameter for the control of creep rate. The thermal cycles, which imply the creation and subsequent dissolution of rafts, provided new dislocations, which explains the acceleration of creep observed under such conditions.     

基于USB的可调光滤波器控制模块设计

分析了可调光倾斜滤波器的工作原理,指出实现光可调倾斜滤波的关键问题,在此基础上设计一种实用的可调光倾斜滤波器控制模块方案.该方案硬件采用内嵌USB模块的微控制器MC68HC908JB8作为主控制芯片,软件以C语言为编程语言,通过USB控制芯片通用接口程序在PC机与微控制器之间建立数据通道,实现了微控制器独立控制与PC机主从控制的双重便利性.系统运行结果表明,该方案结构简单,运行稳定可靠,升级迅速.     

惯性动量轮用高速高效无刷直流电机数字控制系统的应用研究

研究了基于DSP和MC33035组成的高速高效无刷直流电机的数字控制系统。DSP实现控制算法,MC33035完成有位置传感器无刷直流电机的换相控制和功率器件的驱动。该系统能实现对高速惯性动量轮电机(最高转速30 000 r/min)的驱动。采用软件锁相环算法后,转速控制精度可达0.02%,并具有较高的效率和可靠性。     

An Improved Synthesis of N-(4-[18F]Fluorobenzoyl)-Interleukin-2 for the Preclinical PET Imaging of Tumour-Infiltrating T-cells in CT26 and MC38 Colon Cancer Models

Positron emission tomography (PET) imaging of activated T-cells with N-(4-[¹⁸F]fluorobenzoyl)-interleukin-2 ([¹⁸F]FB-IL-2) may be a promising tool for patient management to aid in the assessment of clinical responses to immune therapeutics. Unfortunately, existing radiosynthetic methods are very low yielding due to complex and time-consuming chemical processes. Herein, we report an improved method for the synthesis of [¹⁸F]FB-IL-2, which reduces synthesis time and improves radiochemical yield. With this optimized approach, [¹⁸F]FB-IL-2 was prepared with a non-decay-corrected radiochemical yield of 3.8 ± 0.7% from [¹⁸F]fluoride, 3.8 times higher than previously reported methods. In vitro experiments showed that the radiotracer was stable with good radiochemical purity (>95%), confirmed its identity and showed preferential binding to activated mouse peripheral blood mononuclear cells. Dynamic PET imaging and ex vivo biodistribution studies in naïve Balb/c mice showed organ distribution and kinetics comparable to earlier published data on [¹⁸F]FB-IL-2. Significant improvements in the radiochemical manufacture of [¹⁸F]FB-IL-2 facilitates access to this promising PET imaging radiopharmaceutical, which may, in turn, provide useful insights into different tumour phenotypes and a greater understanding of the cellular nature and differential immune microenvironments that are critical to understand and develop new treatments for cancers.     

通过型固相萃取-液相色谱-串联质谱法同时快速测定鱼肉中7种微囊藻毒素

采用通过型固相萃取净化去除样品基质中脂类物质的干扰,建立了鱼肉中7种微囊藻毒素的液相色谱-串联质谱快速分析方法。样品经80℃水浴热处理后用体积分数为90%的甲醇水溶液进行提取,使用Oasis PRiME HLB通过型固相萃取柱净化。净化后的样品采用Waters XSelect HSS T3色谱柱分离,以0.1%(体积分数)甲酸乙腈溶液和0.1%(体积分数)甲酸水溶液为流动相,梯度洗脱,多反应监测正离子模式扫描,采用基质匹配溶液外标法定量。研究了7种微囊藻毒素的质谱离子化特征,结果表明,酸能显著增加双电荷离子的响应强度。7种目标物在相关范围内线性关系良好,相关系数不低于0.99,定量限为0.30~2.0μg/kg,基质加标回收率为70.6%~96.1%,相对标准偏差为3.4%~9.6%。该方法前处理操作简便,灵敏度和准确度高,可实现鱼肉中多种微囊藻毒素的同时快速测定。     

可食性甲基纤维素复合膜的制备及性能研究

以甲基纤维素(M C)作为基本的成膜物质制备M C膜,在此基础上通过添加其它物质制备出M C复合膜.用抗张强度(TS)、伸长率(E)和水蒸气透过系数(fW)等性能指标评价膜的性能,并确定各种添加物质的最佳添加量,得到性能较好的M C复合膜.     

计算机免疫中基于移动代理的规则提取与规则库构造

计算机免疫系统是防护计算机安全的新兴技术,类MC Agent是计算机免疫系统模型GECISM中的一个代理,是模仿生物免疫系统区分计算机系统中“自我”和“非我”的主要部分.重点介绍了类MC A-gent的设计与实现,包括系统调用短序列的采集、规则的提取以及规则库的构造.     

Aged Brains Express Less Melanocortin Receptors,Which Correlates with Age-Related Decline of Cognitive Functions

Brain G-protein coupled receptors have been hypothesized to be potential targets for maintaining or restoring cognitive function in normal aged individuals or in patients with neurodegenerative disease. A number of recent reports suggest that activation of melanocortin receptors (MCRs) in the brain can significantly improve cognitive functions of normal rodents and of different rodent models of the Alzheimer’s disease. However, the potential impact of normative aging on the expression of MCRs and their potential roles for modulating cognitive function remains to be elucidated. In the present study, we first investigated the expression of these receptors in six different brain regions of young (6 months) and aged (23 months) rats following assessment of their cognitive status. Correlation analysis was further performed to reveal potential contributions of MCR subtypes to spatial learning and memory. Our results revealed statistically significant correlations between the expression of several MCR subtypes in the frontal cortex/hypothalamus and the hippocampus regions and the rats’ performance in spatial learning and memory only in the aged rats. These findings support the hypothesis that aging has a direct impact on the expression and function of MCRs, establishing MCRs as potential drug targets to alleviate aging-induced decline of cognitive function.     

ForceControl组态软件及其在MC尼龙管材中的应用

ForceControl工业控制组态软件是基于分布式实时数据库的3层可组态结构,其内部所有组件可以独立分布运行,并能通过网络服务程序与其它组件交换数据。实践证明,在MC尼龙管材生产监控应用中,能够缩短生产周期,提高生产系统可靠性,监控程序功能完善,综合性能强,人机界面友好。     

串行显示驱动器MC14499及其在单片机系统中的应用

MC144 99是一种BCD码输入 -十进制码输出的串行显示驱动器 .在单片机显示系统中 ,它占用的I/O口线少、单片控制显示位数多并且使用方便可靠 ,得到了广泛应用 .文章介绍了MC144 99的性能特点及其典型应用实例 ,包括通用接口电路设计、显示驱动程序设计及巧用MC144 99DP段构成特殊显示电路的方法、使用技巧等