胰蛋白酶有限水解蚕豆盐溶性蛋白的研究

研究了胰蛋白酶水解蚕豆盐溶蛋白的动力学及其水解物的水溶性。高压液相色谱的实验结果证实胰蛋白酶可以水解蚕豆盐溶蛋白。底物浓度5%、酶与底物之比(E/S)为10U/g蛋白质、pH8.0、温度45℃的酶反应条件下,水解6000s时的蚕豆盐溶性蛋白的水解度达到6.8。蚕豆盐溶蛋白经过胰蛋白酶有限水解后水溶性显著增加,与蚕豆盐溶性蛋白相比,pH8.0时水解度2.1%、4.5%、6.8%的蚕豆盐溶性蛋白水解物的水溶性分别提高350%、390%和510%。     

用激酶抑制剂法筛选球等鞭金藻抗肿瘤活性物质

酪蛋白激酶(Protein Tyrosine Kinases,PTKs)在细胞信号转导途径中起到关键作用,已成为新型抗肿瘤活性物质的重要靶点。实验采用激酶抑制剂法对球等鞭金藻(Isochrysis galbana)的乙酸乙酯、丙酮、正戊醇和水的溶剂萃取物进行检测,结果显示,正戊醇萃取物有较明显的激酶抑制剂活性,抑制率为38.94%;对该萃取物进行薄层层析分离,以丙酮-石油醚(1∶60,v/v)为展开系统,得到Rf值为0.6610的组分,该组分对PTKs具有抑制作用,抑制率为32.21%;对此组分进行硅胶柱层析,以丙酮作为洗脱剂得到的分离组分对PTKs具有强烈的抑制作用,抑制率为86.09%,该组分同时显示出较强的细胞毒活性,这个结果预示着该组分可能是球等鞭金藻中的目的活性物质;同时,激酶抑制剂法较细胞毒活性法方便快捷,灵敏度高,是一种极具潜力的高通量筛选抗肿瘤活性物质的模型。     

Cooking and pasteurizing evaluation of barramundi (Lates calcarifer) meats subjected to an emerging microwave-assisted induction heating (MAIH) technology

Microwave-assisted induction heating (MAIH) is a complex heating process characterized by rapid and uniform heating based on a combination of microwave heating (power: 1000 W; frequency: 2450 MHz) applied from above and electromagnetic induction heating (power: 1500 W) applied from below. In this study, we assessed the utility of MAIH in processing the flesh of barramundi (Lates calcarifer), an important aquaculture species in Asian countries. To determine the effects of different heating conditions on the microbial contamination and physicochemical qualities of barramundi meat, fresh barramundi meats (100 g) were sealed in heat-resistant crystallized polyethylene terephthalate containers containing 150 mL of saline solution, and were subsequently heated in MAIH to 90 °C or 70 °C and held to different time. The results revealed that in response to an increase in the duration of heating, there were reductions in the aerobic plate count, psychrotrophic bacteria count, hydrogen sulphide-producing bacteria count, and coliform count, along with lower contents of total volatile basic nitrogen, in treated samples. Conversely, with a prolongation of the time exposed to heat, we detected increases in the L* (lightness),W (whiteness), ΔE(colour difference), and texture (hardness and chewiness) of fish meat, whereas there was a reduction of a* (redness). When the samples were heated for at least 110 s to 90 °C or for at least 130 s to 70 °C, the barramundi meats obtained appeared to be fully cooked with microbial counts below the limits of detection. In addition, under both heating conditions, thermal imaging revealed a uniform distribution of temperature within treated samples. Furthermore, monitoring of temperature profiles at central points in fish samples revealed that maximum temperatures of 97 °C and 79 °C were reached in response to MAIH processing at 90 °C for 110 s and 70 °C for 130 s, respectively. Thus, on the basis of the quality considerations of appearance, microbial count, and texture, the recommended optimal heating conditions for barramundi meats produced using MAIH are 90 °C for 110 s and 70 °C for 130 s.Industrial relevanceThe MAIH equipment is a novel thermal processing technology and allows food to be heated and pasteurized simultaneously after the package is sealed, eliminates issues of secondary contamination due to the need for subsequent packaging, and extends the shelf life. MAIH technology, therefore, serves as a viable future alternative for thermal processing of manufacturing refrigerated ready-to-eat seafood.     

Stabilization for Schrödinger Equation with Internal Damping and Boundary Disturbance

In this paper, the stabilization for Schrödinger equation subject to internal damping and boundary disturbance at the control end is investigated. Due to its immeasurability, the nonlinear observer system is designed to obtain the state information, and the existence of weak solution and its convergence for the nonlinear observer system are proved. The feedback control is realized by the backstepping transformation. In addition, the adaptive disturbance rejection control is applied to estimate the disturbance. According to the observer and disturbance estimation, the feedback control is finally designed to stabilize the system asymptotically.

     

预制构件厂精益设计方案评价研究

作为新兴产业，预制构件厂的设计和运营是实现装配式建筑构件高效率、高质量生产和配送的关键前提要素。而精益设计可以帮助预制构件厂从源头消除浪费、提高生产效率，所以对预制构件厂构建精益设计方案并且评价实施后的效果无疑是一个重点问题。针对以上问题，本文从节约资金能力、生产能力、交付能力、持续改进能力等4个视角构建出了预制构件厂精益设计评价指标体系，采用了AHP-DEMATEL法确定了指标的权重，并用改进TOPSIS法得到最终结果，最后以某预制构件厂为例验证了精益设计评价指标体系的合理性和可行性。     

Dynamic behaviour and control strategy of high temperature proton exchange membrane electrolyzer cells (HT-PEMECs) for hydrogen production

A fast and safe dynamic process is a key issue during the start-stop and adjustment of high temperature proton exchange membrane electrolyzer cells (HT-PEMECs). In the paper, a 2D multi-physics model is developed to investigate the dynamic process in an HT-PEMEC. First, the dynamic responses of step scheme, multistep scheme and diagonal scheme are compared. It is found that the step scheme has the fastest dynamic response, but it may cause the problem of reactant starvation. The dynamic response speed of diagonal scheme is slower than the step scheme, but it can prevent the problem of reactant starvation. Subsequently, the dynamic process is optimized with a fast dynamic response without reactant starvation. This paper proposes a fast and safe dynamic process adjustment scheme and forms a basis for subsequent control of the HT-PEMEC stack and system.     

Synthesis conditions effect on the of photocatalytic properties of MnWO4 for hydrogen production by water splitting

This work aims to study the synthesis conditions effect on the photocatalytic properties of manganese tungstate (MnWO₄) for H₂ production by the water splitting reaction under visible light irradiation. This is achieved by relating the materials characterization and photocatalytic evaluation of MnWO₄ at different synthesis conditions. MnWO₄ was synthesized through a precipitation reaction between Mn²⁺ and (WO₄)^2- ionic species, while adding oleic acid (OA) as surfactant at two concentrations (0.1% and 1% V) and using three different stirring methods: magnetic stirring (AM), ultrasound (US) and high-shear stirring (UT). Characterization was carried out by TGA, XRD, BET surface area, UV–Vis spectroscopy and FESEM. XRD patterns confirm the wolframite structure of MnWO₄. BET surface area increased by using UT stirring. UV–Vis spectroscopy results revealed indirect transition Eg values of ≈2 eV, favorable for the MnWO₄ photoactivation under visible light irradiation. During the photocatalytic evaluation, sample 1%-UT produced the highest H₂ amount among all samples with a value of 72 μmolH₂g⁻¹, which was far higher compared to WO₃, which was taken as a reference photocatalyst.     

基于图游走的并行协同过滤推荐算法

针对目前协同过滤推荐算法存在的数据稀疏性问题和可扩展性问题,本文进行了相关研究。针对稀疏性问题,在传统的皮尔逊相关相似度中引入交占比系数计算用户间直接相似度,该方法缓解了用户间共同评分项的占比问题;提出一种基于图游走的间接相似度计算方法,该方法根据用户间的直接相似度建立用户网络图,在用户网络图上通过游走计算用户间的间接相似度,并进行推荐。在Spark平台上实现本文方法的并行化,缓解了数据规模增加带来的可扩展性问题。实验结果表明:本文提出的算法在不同数据集上均取得了良好效果,有效地提高了推荐准确度,并且在分布式环境下具有良好的可扩展性。     

农业机器人造型研究与设计

目的为更好地满足用户需求,完善农业机器人造型设计方法。方法采用形态分析法分析设计样本,提取农业机器人造型设计要素及其类目;通过层次分析法计算各造型要素及类目的权重值并进行设计决策,融合权重值不同的设计要素,形成新的造型设计方案集。最终,通过模糊综合评价法得出最优设计方案。以采摘机器人造型设计开发为例,验证了设计流程的科学性。结论作为现代农业智能机械化产品,运用模糊综合层次分析法进行设计决策将有助于提高农业机器人造型设计过程的科学性,形成符合用户需求的造型意象。     

取样方向对含单边裂纹牛卡纸拉伸断裂行为的影响

目的 探究取样方向对含单边裂纹牛卡纸拉伸断裂行为的影响,以期提高牛卡纸为原料制作的包装盒等成品的强度。方法 首先在不同取样方向上制备含单边裂纹的牛卡纸试样,然后基于数字图像相关(Digital Image Correlation, DIC)方法,结合显微张力测试台测得不同取样方向与拉伸断裂载荷的关系图,分析不同取样方向下裂纹尖端微观应变场,最后结合电镜扫描测试进行对比分析。结果 结果表明,通常情况下,含单边裂纹的牛卡纸依然符合纸张纵向拉伸载荷大于横向拉伸载荷的规律,取样方向越靠近横向,裂尖区域应变值越大,发生断裂时的拉伸载荷越小。结论 牛卡纸取样方向和纤维与纤维的结合强度是影响牛卡纸拉伸断裂行为的重要因素。