Effects of non-thermal plasma treating wheat kernel on the physicochemical properties of wheat flour and the quality of fresh wet noodles

The effects of non-thermal plasma (NTP) on the physicochemical properties of wheat flour and the quality of fresh wet noodles ( FWN) were investigated. The results showed that NTP effectively decreased the total plate count (TPC), yeast and mould count (YMC) and Bacillus spp. in wheat flour. Wet gluten contents and the stability time reached the maximum when treated for 20 s. The viscosity of starch increased significantly after treatment due to the increased of damaged starch. The contents of secondary structure were altered to some extent, which was because that the ordered network structure of gluten protein broken. Furthermore, compared with the control, texture properties of FWN were enhanced significantly at 20 s, and the darkening rate of FWN was greatly inhibited due to the low polyphenol oxidase (PPO) activity. Consequently, the most suitable treatment was 500 W for 20 s, providing a basis for the application of NTP in flour products.     

EFFECT OF α-PHASE MORPHOLOGY ON STRENGTHENING AND FRACTURE BEHAVIOUR OF 47121 β-Ti ALLOY

用TEM,SEM,X射线衍射及拉伸试验等研究了47121β-Ti合金的拉伸性能与α相形貌及其断裂行为的关系。结果表明,低温时效由ω相转变成的弥散α相质点,随其体积分数增加,质点间共格应力场发生交叠,产生较强的内应力,在负荷作用下,导致宏观脆断,而微观断裂机制仍属于韧窝,因此可以把局部的内应力区认为是形成精细韧窝的核心。魏氏组织的α相具有强的加工硬化效应,位错切割α相是主要强化机制,但以孪生形变的α相片阻止位错切过。晶界两侧形成的无析出带,以及随后形成的羽毛状α相群,都使晶界区弱化,导致形成类似沿晶型断口。     

NiTi形状记忆合金的相变温度滞后

用透射电镜、正电子湮没和电阻测量,研究了NiTi形状记忆合金的组织结构与相变滞后的关系结果表明,经不同制度时效处理的组织,其相变温度滞后大小的顺序是:片状马氏体>R相>束状马氏体。Ti_(11)Ni_(14)相质点周围的共格应力场对这些相的可逆转变起障碍作用。正电子湮没Doppler展宽能谱S参数值与试样的温度滞后值之间存在线性关系,从而确认Ti_(11)Ni_(14)相析出的错配位错密度及由此而建立的晶体中弹性应力场分布是决定NiTi合金相变温度滞后的主要因素。     

RELATIONS BETWEEN FAILURE BEHAVIOUR AND MICROSTRUCTURE IN TEMPERING STRUCTURE STEELS

用透射电镜研究了两种结构钢的断裂行为与显微组织的关系。结果表明,回火后准解理断口的出现和消失与Fe_3C的析出和聚集密切相关:经250℃回火时析出ε碳化物,呈现单一韧窝断口,回火温度超过350℃时,有Fe_3C析出,这时出现准解理断口,而于450℃回火后达最大比例。在550℃回火后,60Si2Mn钢因Fe_3C聚集,准解理断口消失,又变成单一韧窝断口,37SiMnCrNiMoV钢Fe_3C聚集的倾向小,经550℃回火后仍有少量准解理断口保留下来。观察试样上由负荷产生的残留显微裂纹发现,它们常沿孪晶马氏体的内孪晶界及板条马氏体的条界发展,因此认为这两种脆化了的界面是准解理的解理面,而Fe_3C沿这类界面析出并呈连续分布是导致界面脆化的原因。     

对乙酰氨基酚的合成与生产

综述了国内外近年来对药物扑热息痛（对乙酰氨基酚）合成与生产方法的研究，主要介绍了二步法、一步法和生化法。提出了无论从经济上还是从环保上考虑，一步催化合成法是当今扑热息痛合成的出路     

高速钢中贝氏体的二次硬化特征

研究了6-5-4-2高速钢中贝氏体和马氏体回火后的力学性能和组织结构。结果表明,贝氏体比马氏体具有更高的二次硬化效应以及抗回火稳定性和冲击韧性。透射电镜观察发现,马氏体在二次硬化峰温度范围回火时,有Fe_3C析出,而贝氏体铁素体和奥氏体中只析出弥散的MC和M_2C合金碳化物。这表明在贝氏体长大过程中存在合金元素的扩散。     

用超合金作粘结相的硬质合金的TEM研究

用透射电子显微镜研究了由一种Ni基超合金作粘结相的硬质合金的组织结构。结果表明，烧结后合金的粘结相γ中分布着高度弥散的γ＇相。γ＇相质点在位错网络的结点上择优形核，形貌有粒状和片状两种，大小为10um数量级。观察表明，粘结相γ与WC的湿润性良好，因此用Ni基超合金作硬质合金的粘结相，不仅可节约战略物质Co，而且有可能使硬质合金的性能提高，使用范围扩大。     

SCF FEATURE OF AUSTENITIC STAINLESS STEEL IN BOILING MgCl_2SOLUTION

Corrosion fatigue under the load of low frequency and bigh mean stress has been generallydefined as stress corrosion fatigue(SCF).It is a specific failure process due to the inter-action between stress corrosion cracking(SCC) and corrsion fatigue(CF),the effectsof which on fracture characteristics,including crack initiation and propagation.servicelife and cracking mode have not been investigated systematically.The purpose of this pa-per was to study the environment-sensitive fracture behaviour of OCr18Ni9Ti austeniticstainless steel under the load of different fiequencies and high mean stress in boilingMgCl_2 solution.The interaction between SCC and CF would be emphasized.     

A TEM OBSERVATION OF THE SECONDARY HARDENING PROCESS IN A 6Cr4Mo3Ni2WV DIE STEEL

用电镜薄膜技术研究了6Cr4Mo3Ni2WV基体钢的淬火和回火态的组织结构,着重观察了硬度-回火温度曲线峰值附近的结构,指出合金的二次硬化主要由V_4C_3和M_2C沉淀产生.回火时沿马氏体内孪晶界和{112}晶面析出的片状渗碳体,低于450℃是稳定的,高于500℃是亚稳相,它在回火过程中转变为V_4C_3,M_2C和新的细化渗碳体,这对二次硬化也有贡献;但更主要的是这种转变使合金的冲击韧性α_K值显著提高.在600—650℃亚稳渗碳体的转变区复合转变为M_6C和Cr_7C_3,同时沿原始奥氏体晶界和亚晶界析出连续的等轴M_6C和Cr_7C_3,这一过程又使α_K值下降.     

Fast Ion Transport in Li-Rich Alloy Anode for High-Energy-Density All Solid-State Lithium Metal Batteries

All-solid-state Li batteries (ASSLBs) with solid-polymer electrolytes are considered promising battery systems to achieve improved safety and high energy density. However, Li dendrite formation at the Li anode under high charging current density/capacity has limited their development. To tackle the issue, Li-metal alloying has been proposed as an alternative strategy to suppress Li dendrite growth in ASSLBs. One drawback of alloying is the relatively lower operating cell voltages, which will inevitably lower energy density compared to cells with pure Li anode. Herein, a Li-rich Li₁₃In₃ alloy electrode (LiRLIA) is proposed, where the Li₁₃In₃ alloy scaffold guides Li nucleation and hinders Li dendrite formation. Meanwhile, the free Li can recover Li's potential and facilitate fast charge transfer kinetics to realize high-energy-density ASSLBs. Benefitting from the stronger adsorption energy and lower diffusion energy barrier of Li on a Li₁₃In₃ substrate, Li prefers to deposit in the 3D Li₁₃In₃ scaffold selectively. Therefore, the Li–Li symmetric cell constructed with LiRLIA can operate at a high current density/capacity of 5 mA cm⁻²/5 mAh cm⁻² for almost 1000 h.