预变形对X90管线钢显微组织和力学性能的影响

采用拉伸试验、冲击试验、光学显微镜(OM)、扫描电镜(SEM)、显微硬度测试仪等研究了0.5%~6%预拉伸变形对X90管线钢显微组织及力学性能的影响。结果表明:随着预拉伸变形量的增加,X90管线钢晶粒增大,位错塞积导致强度增加,均匀延伸率下降,呈现典型的加工硬化特点,抗拉强度的增幅要小于屈服强度,屈强比增大;随着变形量的增加冲击吸收功逐渐由291J减小至235J,冲击试样断口的韧窝减小,伴随第二相粒子析出;显微硬度中间层较边缘区增加少,预拉伸在6%时边缘显微硬度为325HV。X90管线钢的预拉伸在4%以内能保证管线钢的正常服役。     

Synthesis,photophysical properties,and application of optical brighteners based on stilbene-oxadiazole derivatives

A series of symmetrical optical brighteners based on stilbene-oxadiazole derivatives were prepared by the simple synthetic route of a condensation reaction between 4,4′-dicarboxystilbene and N,N′-carbonyldiimidazole reagent, forming stilbene 4,4′-ethene-1,2-diyldibenzohydrazide as a key intermediate. The obtained compounds were characterised by analysis of nuclear magnetic resonance, mass spectrometry, and elemental analysis data. The absorption maximum wavelength, fluorescence emission wavelength, and fluorescence quantum yield were measured in N,N-dimethylformamide solution at room temperature, and the fluorescence properties of the prepared compounds in the solid state were observed and measured. The compounds exhibited bluish and greenish fluorescence emission, with the fluorescence quantum yield in the range 0.2–0.8; the effects of substituents on the emission spectra of these compounds were interpreted. The prepared compounds were applied as optical brighteners to polyester and polyamide-6 fabrics at various concentrations, and their CIE whiteness index and fastness properties were studied.     

花生粕酿酒工艺及花生发酵酒风味物质和营养成分分析

以花生粕为主料,糯米为辅料进行液态发酵酿制花生发酵酒。通过单因素实验和正交实验探讨了花生粕酶解液添加量、SO2添加量、酵母添加量、主发酵温度、主发酵p H对花生发酵酒酒精度和感官品质的影响,同时对其营养成分和风味物质进行了测定分析。结果表明:花生发酵酒的最佳主发酵工艺条件为花生粕酶解液添加量90 m L/L,SO2添加量50 mg/L,酵母添加量4 g/L,主发酵温度20℃,主发酵p H 4。在最佳主发酵工艺条件下酿制得到的花生发酵酒酒精度为13.7%,品质最佳。     

2-溴苯酚合成工艺的优化研究

2-溴-4-叔丁基苯酚与甲苯的叔丁基转移反应可以形成重要的有机中间体2-溴苯酚。考察了催化剂及反应条件对叔丁基转移反应的影响,结果表明,三氯化铝及其与叔胺盐酸盐的复合盐对叔丁基转移反应的具有较好的催化活性,27AlNMR的分析表明催化活性中心可能是三氯化铝与水解产生的氯化氢反应形成的氯铝酸。进一步研究表明,氯化氢及溴化氢可提高三氯化铝的催化活性,降低三氯化铝的用量。优化后的工艺条件：在二氯甲烷溶剂中,4-叔丁基苯酚与溴素在0℃反应选择性形成2-溴-4-叔丁基苯酚,加入摩尔分数为30%的AlCl3及600%的甲苯,30℃“一锅法”反应制备2-溴苯酚,2-溴-4-叔丁基苯酚反应的转化率及选择性可达96.5%、99.6%。     

食品功能因子稳态化靶向递送与精准营养

膳食结构与营养平衡对于人体健康具有重要作用,不合理的膳食与慢性疾病高发密切相关。精准营养旨在针对个体背景特征进行安全、高效的营养干预,改善膳食失衡,维持人体健康并有效预防和控制疾病。食品中的功能因子能通过激活酶的活性或其它途径调节人体机能,是实现精准营养的重要物质基础,也是营养调控的重要手段。针对功能因子溶解性不好、稳定性差和生物利用度低等问题,建立稳态化靶向递送体系,有助于改善功能因子的稳定性并提高其生物利用度,实现体内的靶向作用位点控制释放,为精准营养提供营养干预途径和方法。本文概述精准营养与生命健康的重要联系,食品功能因子靶向递送对实现精准营养的促进作用,以及面临的瓶颈问题;论述食品功能因子稳态化靶向递送与控释的现状,以及与精准营养的内在联系和重要作用。详细介绍活性多肽、不饱和脂肪酸、多酚及类胡萝卜素等稳态化靶向递送对炎性肠病、癌症、酒精性脂肪肝、动脉粥样硬化和肥胖等疾病的营养干预作用。对国内精准营养产业发展动态、存在的机遇与挑战进行总结和展望,旨在为食品功能因子稳态化靶向递送与产业化应用提供参考。     

钢琴乐声仿真频谱模型研究

频谱模型的乐音仿真是运用声学理论,由一系列基本函数及其时变幅度乘积的迭加来实现乐器的发声。通过对钢琴琴弦振动和衰减特性的分析以及共鸣箱共振作用的探讨,提出了一种新的数字化钢琴乐音仿真技术,仿真模型由激励系统和共振系统两部分组成。系统以琴弦振动方程为基础,先进行时域上的包络修饰,以模拟琴弦振动的自然衰减,这样可以使乐音各音符间衔接和谐;然后在频域上以频谱包络建模滤波器组,实现共振系统的仿真,对音色进行修饰。该方法能更为有效的雕刻声音,同时较好的表现音色,从而使乐音听起来更加和谐。     

纯钛微台阶精密连接技术

纯Ti微台阶为ICF研究中重要的基础靶型,由于物理实验的高度精密性,传统加工方法不能满足靶制备需求。研究了纯Ti微台阶的精密扩散焊接技术,获得高质量的标准台阶,其表面粗糙度Rq<100 nm、厚度一致性<100 nm、界面连续无显微缺陷、晶体结构均匀,未检测出杂质。     

Influence of carbon nanotubes and dispersions of SiC on the physical and mechanical properties of pure copper and copper‐nickel alloy

This paper investigates the physical and mechanical properties of copper‐nickel alloy (at 50 wt.%–50 wt.%) and pure copper, mixed with various types of reinforcement materials such as carbon nanotubes (0.5 wt.%–2 wt.%) as nanoparticles, silicon carbide (1 wt.%–4 wt.%) as microparticles. The acquired composite specimens characteristics were estimated such as microstructure, density, electrical and thermal conductivity, hardness, and compression stress properties to determine the suitable reinforcement percentage that has the best physical and mechanical properties with different main matrix material whether copper‐nickel mechanical alloying or pure copper powder. The micron‐sized silicon carbide and nanosized carbon nanotubes were added to improve the mechanical and physical properties of the composite. The electrical and thermal conductivity of pure copper alloy enhanced compared with the copper‐nickel alloy matrix material. The hardness and compression yield stress of both pure copper and copper‐nickel composites have enhancement values and for copper‐nickel base composites hardness and compression yield stress have enhanced with the most positive enhancement values to examined an optimum percentage of reinforcing material.     

Predicting muscle forces measurements from kinematics data using kinect in stroke rehabilitation

Muscle strength is mostly measured by wearable devices. However, wearing such devices is a tedious, unpleasant, and sometimes impossible task for stroke patients. In this paper, a mathematical model is proposed to estimate the strength of the upper limb muscles of a stroke patient by using Microsoft Kinect sensor. A prototype exergame is designed and developed to mimic real post-stroke rehabilitation exercises. Least-square regression matrix is used to find the relation between the kinematics of the upper limb and the strength of the corresponding muscles. Kinect sensor is used along with a force sensing resistors (FSR) glove and two straps to collect both, real-time upper limb joints data and the strength of muscles of the subjects while they are performing the exercises. The prototype of this system is tested on five stroke patients and eight healthy subjects. Results show that there is no statistically significant difference between the measured and the estimated values of the upper-limb muscles of the stroke patients. Thus, the proposed method is useful in estimating the strength of the muscles of stroke patient without the need to wear any devices.