An International Collaborative Study on Trypsin Inhibitor Assay for Legumes,Cereals, and Related Products

For determining trypsin inhibitor activity (TIA) in soy products, the American Oil Chemists' Society (AOCS) Method Ba 12-75 has been used. It measures differences in absorbance at 410 nm of bovine trypsin activity toward a synthetic substrate (Nα-benzoyl-DL-arginine-p-nitroanilide) in the absence and presence of an inhibitor. Recently, a significantly improved method was developed (JAOCS, 2019, 96:635–645), featuring 5 mL of total assay volume, enzyme-last sequence, and single inhibitor level in duplicate. It is proposed as the AOCS Method Ba 12a-2020. As a part of the AOCS method approval process, a collaborative study involving 12 international laboratories was conducted to evaluate the performance of the proposed method. The study involved measuring TIA in 10 selected test samples plus a blind duplicate. They included soybeans, pulses, cereals, and their processed products (flours, concentrates, and isolates). After rigorous statistical treatment of the data, only three outliers were removed from the data of two samples. Repeatability relative standard deviations (RSDr) for the 11 samples ranged from 0.99% to 5.52%. Reproducibility RSD (RSD_R) ranged from 7.07% to 22.92%, with seven samples having RSD_R around 10% or less. The remaining four samples had very low TIA, and their RSD_R values ranged from 13.34% to 22.92%. The study has demonstrated reliable performance of the proposed AOCS method. Several collaborators carried out additional experiments addressing some aspects of the method, leading to further refinements. The proposed method is undergoing evaluation by the AOCS Uniform Methods Committee for adoption as an Official Method for measuring TIA in various legume and grain products.     

微合金化磁极钢板化学成分与磁性能的关系分析

采用多元线性回归分析方法分析微合金化磁极钢板化学成分与磁感应强度K、B100的关系，并用剩余碳含量的概念，得出显著性较高的磁极钢板磁性能与硫及剩余碳含量关系的回归式。     

Failure analysis of beta-C titanium alloy high-pressure vessels

An attempt has been made to apply the linear elastic fracture mechanics concept to Beta-C titanium alloy pressure vessels that exhibited brittle fractures during hydrotesting. Based on the results of stress analysis on the real structures and fracture surface examinations, a stress-intensity factor,K _IC, was estimated. TheK _IC value of the material in the cracking direction was measured by a surface semi-elliptical crack method. It was found that theK _IC value of the material is very close to the estimated stress-intensity factorK _I during failure, which places the pressure vessels in a critical condition in that a small variation in flaw size may cause a catastrophic failure. A compromise must be made betweenK _IC and the required yield strength. In this restricted case, the yield strength of the material should be controlled in the range of 1150 to 1200 MPa to avoid brittle fracture and the possible occurrence of yield during hydrotesting. Control of microstructure and other mechanical properties is also discussed in this investigation.     

大型铝合金叶片金属型铸造工艺分析

针对铝合金叶片的铸造缺陷，分析指出浇注位置、浇注系统设计、型腔排气和充型温度场是造成铸造缺陷的主要因素，据此，有针对性地提出了铸型倾斜、平浇竖冷、沿分型面开设排气槽、改变涂料层厚度以及调整凝固顺序等改进措施，其效果在生产中得到验证。     

宝钢No.3高炉炉壳孔洞应力弹性分析

针对高炉炉壳各种复杂的开发及受力情况，结合宝钢No．3高炉炉壳开孔实例，建立相应的四种数学模型，利用美国ALGOR计算软件中的SSAPO计算模块，作有限元应力计算并进行孔洞弹性应力分析的讨论，以判断高炉开孔的安全可靠性。     

国外TOFD检测标准分析和比较

概述了超声波衍射时差法（TOFD），对目前世界上主要的七个TOFD检测标准或规范进行了分析和比较，归纳了其中十二个方面的异同点。为我国TOFD检测标准的制订和TOFD技术的发展提供参考。     

我国应重视铁素体及铁素体/奥氏体不锈钢管材的开发

低铬的实用型铁素体不锈钢和低镍的铁素体/奥氏体双相不锈钢是国际上1980年以后迅速发展的两类不锈钢管材新品种。前者以低成本而成为在低腐蚀环境下应用如汽车排气管等的优选管材,后者则以高强度和高耐腐蚀性能的优良组合而成为在含氯离子、H2S等应力腐蚀环境下使用的部件首选材料。介绍了这两类不锈钢(焊)管的研究情况及应用前景,并建议我国应重视和加强对这类不锈钢管材的开发。     

钻杆内螺纹接头失效分析

介绍了葡北4-11井场新钻杆发生内螺纹接头失效事故的有关情况,对失效钻杆进行了宏观分析与断口微观分析以及材质理化检验,从钻杆结构和载荷两个方面探讨了发生失效事故的主要原因,并提出了改进建议。     

新临钢连铸板坯中间裂纹的成因分析与改进措施

根据新临钢Q235钢的连铸生产数据,并通过对连铸板坯中间裂纹的低倍研究、能谱分析等,对连铸板坯中间裂纹的形成原因和影响因素进行分析探讨,认为钢中S含量高,Mn/S值较小,是连铸板坯产生中间裂纹的主要原因。而辊缝开口度、浇注速度、钢水过热度也是中间裂纹产生和扩展的影响因素。并据此提出了减少铸坯中间裂纹的具体改进措施。     

穿孔顶头使用寿命浅析

分析了顶头的各种失效形式及产生的原因,提出了提高顶头使用寿命的措施。即应根据顶头的具体工作条件,制定合理的热处理工艺;采用复合处理工艺,解决好顶头单纯氧化处理热强性不高的问题等。