栉孔扇贝外套膜酸性和碱性磷酸酶电镜细胞化学研究

采用电镜细胞化学技术对栉孔贝（Chlamys farreri）外套膜中的酸性磷酸酶（ACP）和碱性磷酸酶（AKP）进行了定性定位研究。结果表明，外套膜的所有上皮细胞和结缔组织中部分务细胞呈ACP强阳性。上皮细胞中高电子密度阳性颗粒多为圆形，直径300－450mm；内多也呈ACP强阳性；微绒毛等呈弱阳性。血细胞中次级溶酶体内有数目和大小不同的ACP强阳性颗粒；内质网等内膜系统呈ACP弱阳性。外套膜的所有上皮细胞和血细胞均呈AKP强阳性。AKP阳性颗粒常沿着细胞膜分布；内质网等内膜系统呈AKP强阳性；上皮细胞中一种近圆形直径约250－420nm的颗粒也呈AKP强阳性。     

Feedrate optimization and tool profile modification for the high-efficiency ball-end milling process

Trend in die/mold machining is to produce highly quailed surface using the high-speed hard machining with the ball-end cutter. The ball-end milling is, however, less efficiency than the flat end milling. It is important to optimize the feedrate that gives the maximum material removal rate constrained by an allowable surface roughness. The state-of-art of the CBN ball-end cutter technology allows increasing the tooth feed for high-speed and high-efficiency machining. However, because the spherical shape of the cutter can result in the scallop-liked cusps on the machined surface, the surface roughness consideration makes a feedrate limitation to the CBN cutter. In this paper, the optimization of the feedrate by considering the generated-scallop effect of the ball-end cutter has been studied. It was found that the tooth feed must be kept within one third of the path pick in order to keep the feed-interval scallop height not over the path-interval scallop height. Therefore, the potential capability of the CBN cutter for the larger tooth feed (i.e. high efficient) machining can not be fully exploited. It was found a notch-cut on the center of the ball-end cutter reduced the feed-interval cusp height, thus allowing an increased feedrate of more than 50% compared with the standard ball-end cutter. If the parameters of the notch-cut profile can be optimized, it is believed that the feedrate can be further increased.     

Determination of γ-glutamyl-valyl-glycine in raw scallop and processed scallop products using high pressure liquid chromatography–tandem mass spectrometry

The determination of the kokumi peptide, γ-glutamyl-valyl-glycine (γ-Glu-Val-Gly) in raw scallop and processed scallop products was carried out using high pressure liquid chromatography–tandem mass spectrometry (LC/MS/MS). The detection of γ-Glu-Val-Gly was achieved using a multiple reaction monitoring (MRM) method. The optimised condition enabled the precise determination of γ-Glu-Val-Gly. Raw scallop contained 0.08 μg/g γ-Glu-Val-Gly, and the γ-Glu-Val-Gly levels in processed scallop products, such as dried-scallop and scallop extract, were measured to be 0.64 and 0.77 μg/g, respectively. This is the first report to confirm the existence of γ-Glu-Val-Gly in foodstuff.     

真空冷冻干燥升华干燥时间的实验研究

本文以扇贝为研究对象,采用二次正交回归组合试验,建立了真空冷冻干燥升华时间和单位厚度升华时间的二次多元回归模型,利用降维法分析了干燥室压强、物料厚度和加热板温度三个主要过程参数对真空冷冻升华干燥时间的影响。结果表明,干燥室压强、物料厚度和加热板温度对升华干燥时间影响显著,呈二次函数规律变化,影响的主次因素依次为:物料厚度、干燥室压强、加热板温度。对单位厚度升华干燥时间进行岭嵴分析,给出了在本试验三因素取值范围内的冻干过程优化参数:干燥室压强为50Pa;物料厚度为9mm;加热板温度为39℃,优化的物料单位厚度升华干燥时间为0.146h。     

Kinetics and equilibrium studies of removal of an azo dye from aqueous solution by adsorption onto scallop

In the present work removal of an azo dye (Reactive Black 5) was investigated from aqueous solution by adsorption onto scallop as a low-cost and widely available adsorbent. The effect of various operational parameters, such as contact time, pH, initial dye concentration and adsorbent dosage on the removal efficiency of dye was studied. Removal efficiency declined with the increase in solution pH and initial dye concentration but with the decrease in adsorbent dosage. Experimental equilibrium and kinetics data were fitted by Langmuir and Freundlich isotherms and pseudo-first-order and pseudo-second-order kinetic models, respectively.     

复杂曲面五坐标数控铣削表面粗糙度预测的关键技术研究

针对CAD/CAM复杂曲面数控加工刀位点曲率与走刀行距关系进行分析,给出了不同刀具路径下走刀行距的计算方法,并且对影响表面粗糙度的因素进行了讨论,该方法可用于对表面粗糙度的一个范围进行预测.并提出一种基于主曲率匹配的等残留高度刀具路径规划改进算法,该方法能够提高加工效率,改善加工表面粗糙度.     

Citric acid as pretreatment in drying of Pacific Lion’s Paw Scallop (Nodipecten subnodosus) meats

Pacific Lion’s Paw Scallop meats were dried at 50, 60, and 70 °C after pretreatment in citric acid at pH 3 during zero (control), one, and three hours. Immersion in the acid solution reduced the scallop pH from 6.20 to 5.99 (1 h) and 5.88 (3 h) and directly affected the drying times. At 50 °C drying times were 22, 10 and 8.5 h, at 60 °C they were 15, 9.5 and 8 h, and at 70 °C they were 13, 8 and 6 h for control, 1 h, and 3 h of acid treatment. Drying times were considerably reduced as acid immersion time increased. The drying temperature had no significant effect (p ? 0.05) on colour and texture, whereas the acid treatment had a significant effect (p < 0.05), with the control scallops having greater hardness and a more intense dark colouration than those treated with acid (p < 0.05). The citric acid treatment in drying meats of scallops is a good option to decrease the drying times and therefore the process cost. Moreover, the final product has a better colour because the acid treatment reduces Maillard reaction.     

扇贝边活性肽的分离及其对羟自由基的清除活性研究

目的:确定扇贝边酶解产物中对羟自由基(·OH)具有清除作用的活性肽的分布及活性肽分子量的大小。方法:采用葡聚糖凝胶G-25和G-200分别对扇贝边酶解产物进行分离,用标准分子量作为参照,检测各分离组分对羟自由基的清除率及活性肽分子量的大小。结果表明:枯草杆菌蛋白酶酶解扇贝边的酶解产物中,有两个分离组分具有羟自由基清除活性,其对应的活性肽分子量为8000Da和1800Da,这两种活性肽对羟自由基的清除率分别为73.6%和64.3%;木瓜蛋白酶酶解扇贝边的酶解产物中,也有两个分离组分具有羟自由基清除活性,其对应的活性肽分子量为9000Da和1400Da,这两种活性肽对羟自由基的清除率分别为72.7%和66.1%。结论:用枯草杆菌蛋白酶和木瓜蛋白酶酶解扇贝边所得的酶解产物中分别含有两种对羟自由基具有清除作用的活性肽。     

A Path Interval Generation Algorithm in Sculptured Object Machining

The features of a sculptured object are represented by a set of section curves. A fast algorithm is presented to calculate cutting depths based on the scallop height using these curves. The calculated cutting depth can be used for tool-path generation. This tool-path generation approach is particularly useful for constant z level contouring and high-speed machining.     

基于正向杜邦指标线的五坐标侧铣加工

为实现叶轮类零件的多坐标侧铣加工,通过引入正向杜邦指标线,利用鼓锥形刀对自由曲面的五坐标侧铣加工进行研究。针对具有严格凸切削刃的侧铣加工刀具,提出不发生局部干涉的充要条件是切触点处刀具曲面的正向杜邦指标线位于被加工曲面的正向杜邦指标线之内。给出利用鼓锥形刀侧铣加工自由曲面时实施干涉检查的判断准则以及消除干涉的修正方法,推导出具有严格凸切削刃的刀具在给定的残留高度下侧铣加工带宽的计算方法。在此基础上,利用等残留高度法实现鼓锥形刀侧铣加工自由曲面无干涉刀具轨迹的生成。算例表明,在相同残留高度下,鼓锥形刀侧铣较之球头刀加工效率提高37.44%,说明侧铣加工是提高切削效率和加工质量的一种有效途径。