复合酶法水解花生粕制备抗氧化肽的工艺优化

以DPPH自由基清除率和收率为响应值,采用响应面法对复合酶法水解花生粕生产抗氧化性肽工艺条件进行了优化.研究结果表明,碱性蛋白酶和中性蛋白酶对花生粕具有较强的水解能力,二者以2∶1的比例对花生粕水解时,较优水解条件是50℃,pH值8.54,底物质量分数8.34%.在此条件下酶解16 h,花生肽收率为65.80%,在花生肽质量浓度为0.55 mg/mL时,对DPPH自由基清除率为25.77%,与优化前相比,复合酶比碱性蛋白酶单酶水解时收率和DPPH自由基清除率分别提高了7.48%和7.66%,比中性蛋白酶单酶水解时分别提高了10.29%和22.53%.     

Passivity breakdown of 13Cr stainless steel under high chloride and CO2 environment

Herein, the effect of high chloride ion (Cl-) concentration on the corrosion behavior and passive film breakdown of 13Cr martensitic stainless steel under CO₂ environment was demonstrated. The Cl- concentration was varied from 30 to 150 g/L and cyclic potentiodynamic polarization was conducted to investigate the influence of the Cl- concentration on the corrosion potential (E_corr), passive breakdown potential (E_pit), and repassivation potential (E_rep). The results of the polarization curves revealed that 13Cr stainless steel is susceptible to pitting under high Cl- concentration. The passive breakdown potential and repassivation potential decreased with the increase of Cl- concentration. The semiconducting behavior of the passive film was investigated by Mott-Schottky analysis and the point defect model (PDM). It was observed that the iron cation vacancies and oxygen vacancies were continuously generated by autocatalytic reactions and the higher Cl- concentration resulted in higher vacancies in the passive film. Once the excess vacancies condensed at the metal/film interface, the passive film became locally detached from the metal, which led to the breakdown of the passive film.     

Effects of conform continuous extrusion and heat treatment on the microstructure and mechanical properties of Al-13Si-7.5Cu-1Mg alloy

The effects of conform continuous extrusion and subsequent heat treatment on the mechanical and wear-resistance properties of high-alloying Al-13Si-7.5Cu-1Mg alloy were investigated. The microstructures of alloys before and after conform processing and aging were compared by transmission electron microscopy and scanning electron microscopy, respectively. The results reveal that the primary phases were broken and refined by intense shear deformation during conform processing. After the conform-prepared Al-13Si-7.5Cu-1Mg alloy was subjected to solid-solution treatment at 494℃ for 1.5 h and aging at 180℃ for 4 h, its hardness improved from HBS 115.8 to HBS 152.5 and its ultimate tensile strength increased from 112.6 to 486.8 MPa. Its wear resistance was also enhanced. The factors leading to the enhanced strength, hardness, and wear resistance of the alloy were discussed in detail.     

离子液体型表面活性剂改性皂土对碱性红的吸附研究

以溴化十六烷基咪唑和溴化十二烷基吡啶两种离子液体型表面活性剂作为有机改性剂,通过微波辐射技术制得改性有机皂土吸附剂(简称有机皂土1和有机皂土2),并以红外光谱对其进行表征。研究了有机皂土的吸附时间、吸附温度、溶液的pH值、初始浓度等因素对碱性红吸附的影响。研究结果表明:在吸附时间约10 min内去除率达96%以上,吸附的稳定时间 40 min,在实验的温度、溶液的pH值范围内对碱性红吸附的去除率95%～97%,有机皂土对碱性红的吸附作用是一个自发的过程,吸附过程更符合单分子层吸附的Langmuir等温吸附模型以及拟二级动力学的模型。     

第13届中国大学生田径锦标赛跳跃项目运动员赛前训练研究

目的:赛前训练的跨度、训练内容的选择、方法手段的运用,以及运动负荷的安排,决定了赛前训练的效果.通过对第13届中国大学生田径锦标赛跳跃项目运动员赛前训练进行调查,研究中国大学生跳跃项目运动员赛前训练的特征与规律,为跳跃项目大学生运动员赛前训练提供参考.方法:采用文献资料、问卷调查、访谈、数理统计、逻辑分析等方法,对第13届中国大学生田径锦标赛跳跃项目运动员赛前训练的时间学特征、负荷特征、训练内容、方法与手段等指标进行研究.结果:1第13届中国大学生田径锦标赛跳跃项目运动员赛前训练时间一般为8~10周,分为动员阶段、加量阶段、强化阶段、赛前诱导四个阶段.2跳跃项目运动员赛前训练的负荷量,周课次安排在4~6次左右,每次课时间安排为90~120min.赛前训练的总负荷量平均安排在5 040min,其中最小值为2 880min,最大值为7 200min,负荷密度控制范围在80%~95%左右.赛前减量训练过程中的专项训练强度安排在85%~95%.赛前减量训练中的专项训练强度是平时训练强度的65%~80%.3跳跃项目运动员赛前训练的基本内容比例安排主要以专项速度和专项技术为主,平均比例为21.95%和23.63%.4跳跃项目运动员的赛前训练的方法以重复训练法和间歇训练法为主,技术训练以完整训练法为主.赛前训练的内容分为力量、速度、耐力、灵敏、柔韧和协调性等六个部分.     

米渣营养成分测定及其蛋白质提取工艺优化

以大米为对照,测定了米渣的营养成分,并对碱溶酶解法提取米渣蛋白质的工艺进行优化。以蛋白质提取率为指标,首先通过单因素实验确定提取条件,然后采用正交试验设计优化碱溶工艺和酶解工艺,并分别采用线性模型和二次多项式模型进行回归拟合。实验结果显示,米渣蛋白质提取条件为米渣粗粉质量与碱溶液体积的比例是1∶12g/mL,碱溶pH值为12.5,米渣粗蛋白质量与碱溶液体积的比例是1∶10g/mL,酶解pH值为10.0,碱性蛋白酶的w(酶)为2.0%,在此最优条件下,蛋白质的提取率可达21.35%。二次多项式拟合方程式能很好地拟合碱溶酶解法提取米渣蛋白质的过程,决定系数R²=1.000。     

Ni~(2+)对Cu~+-13X分子筛动态吸附脱硫性能的影响

采用液相离子交换法制备Cu+-13X和Ni2+/Cu+-13X分子筛吸附剂,运用X线衍射仪(XRD)、扫描电子显微镜(SEM)和傅里叶红外光谱仪(FT-IR)等对样品进行表征。在常温和常压下,通过固定床吸附实验研究Cu+-13X和Ni2+/Cu+-13X对含有噻吩(TP)、2-乙基噻吩(2-ETP)的双组分模拟汽油的动态吸附脱硫性能。结果表明:Ni2+/Cu+-13X分子筛中Ni2+质量分数为1.54%时,Ni2+/Cu+-13X分子筛吸附脱硫效果最佳。动态吸附实验过程中,噻吩类硫化物与2种吸附剂之间均存在π配位作用,且噻吩与2-乙基噻吩之间存在竞争吸附,而Ni2+可以增大Cu+-13X吸附剂对2-乙基噻吩的吸附选择性;负载的Ni可以作为一种助剂,增加Cu+-13X吸附剂对噻吩类硫化物的吸附量,在相同的实验条件下,经Ni2+改性后的Cu+-13X对噻吩和2-乙基噻吩的穿透吸附量和饱和吸附量分别增加了66.9%、35.5%和24.4%、18.2%。     

汽油火灾烟气净化碱性发泡液的性能及应用实验

为研究泡泡消烟技术在汽油火灾烟气净化中的有效性,水中添加质量分数1%月桂酰两性基二乙酸二钠(LAD)表面活性剂制备发泡液,并加入Na₂S₂O₃,Na₂SO₃,NaHCO₃,NaOH等碱性添加剂制成碱性发泡液。通过分析发泡液的表面张力、黏度、泡沫性能、pH值及汽油燃烧残留物(炭黑)沉降时间等性能指标,确定最优消烟发泡液为质量分数1%的LAD溶液添加质量分数0.4%Na₂SO₃碱性添加剂;使用自制烟气收集净化装置对发泡液的净烟效果测试发现,汽油烟气被包裹在泡泡中而难以溢散并被泡泡液缓慢吸附、中和,使得反应后溶液的pH值大幅降低;模拟隧道汽油火灾黑烟净化实验测得泡泡喷射作业150 s能使黑烟浓度降低97.8%。碱性发泡液能有效净化汽油火灾烟气。     

基于图像处理的EAN-13条码识别算法

重点介绍了EAN13条码的编码特点和基于图像技术的EAN-13条码识别算法,结合该算法给出了几种条码识别的测试结果,从而能够实现对纸基不平整导致印刷不好的条码识别。     

有机物添加剂对碱性锌电极的影响

通过腐蚀实验,测量了锌在碱性溶液中的腐蚀速度,比较了几种有机物添加剂的缓蚀效果。用恒电位极化的方法研究了锌的沉积电流随时间的变化。企图用该考查一些有机物添加剂对二次碱性锌电极枝晶生长的抑制作用。了多孔锌电极在含有各种有机物添加剂的碱液中的阴,阳极极化曲线。