Cold Oxygen Plasma Treatments for the Improvement of the Physicochemical and Biodegradable Properties of Polylactic Acid Films for Food Packaging

The effects of cold plasma (CP) treatment on the physicochemical and biodegradable properties of polylactic acid (PLA) films were studied. The PLA films were exposed to CP for 40 min at 900 W and 667 Pa using oxygen as the plasma‐forming gas. The tensile, optical, and dynamic mechanical thermal properties, surface morphology, printability, water contact angle, chemical structure, weight change, and biodegradability properties of the films were evaluated during storage for up to 56 d. The tensile and optical properties of the PLA films were not significantly affected by CP treatment (CPT; P > 0.05). The surface roughness and water contact angle of PLA films increased by CPT and further increased during storage for 56 d. The printability of the PLA films increased following CPT and remained stable throughout the storage period. CP‐induced hydrophilicity was also sustained during the storage period. The PLA films lost 1.9% of their weight after CPT, but recovered 99.5% of this loss after 14 d in storage. Photodegradation, thermal, and microbial biodegradable properties of the films were significantly improved by CPT (P < 0.05). Accelerated biodegradation of CP‐treated PLA sachets with and without cheese was observed in compost. These results demonstrate the potential of CPT for modifying the stiffness, water contact angle, and chemical structure of PLA films and improving the printability and biodegradability of the films for food packaging.     

不同感官质量曲药在培曲过程中理化指标变化规律研究

从五粮液中温曲多批次曲药中选取感官质量差异较大的两个批次曲药作为研究对象,分别对其培曲过程中发酵力、糖化力、温度和水分等理化指标进行分析研究,为进一步优化培曲过程管理,提升曲药质量提供重要依据。结果表明：在培曲过程中,优质曲与普通曲的理化指标变化趋势大体一致,但变化过程存在差异。优质曲的糖化力整体偏低,平均值为300～400 mg/（g·h）;而普通曲糖化力整体较高,平均值为400～500 mg/（g·h）。优质曲的发酵力整体偏高,平均在400～500 mL/（g·72 h）之间;普通曲则整体偏低,平均在300 mL/（g·72 h）左右;优质曲酵母菌数量在培曲第8天左右可达到约107个/g曲药,约是普通曲的10倍。 关键词：中图分类号：TS262.3 文章编号：0254-5071（20１6）10-0116-04 doi:     

综采工作面推进速度与支架工作阻力的研究

为了使察哈素煤矿31201工作面在末采段的支架能够安全回撤,实现贯通时顶板无来压的目标,运用理论分析与现场实测,研究推进速度对支架工作阻力的影响。首先对支架工作阻力的确定方法进行介绍,其中包括3种方法;其次通过对推进速度与围岩应力的理论分析,得出随着综采面推进速度的增加,支架工作阻力减小;最后,将实测支架工作阻力与推进速度进行线性回归,得出随推进速度的增加,支架循环末阻力下降。掌握这一规律能够有效指导末采,保证支架安全回撤。     

基于模糊调整的矿井提升机速度控制方法

为了满足现场矿井提升机对不同工况的性能需求,研究了基于模糊调整的PI速度调节器,以转速和转矩作为模糊化输入。实验结果表明,系统在轻载和重载、低速和高速时均具有较好的控制性能,可以同时满足生产和检修运行需求。     

河北宣化“战国红”玛瑙的结构特征及颜色成因

宣化“战国红”玛瑙是指产于河北省张家口市宣化县塔儿村乡滴水崖、王千户一带的缟玛瑙,主要颜色为红色和黄色。以宣化“战国红”玛瑙原石为研究对象,利用偏光显微镜、环境扫描电子显微镜和拉曼光谱等测试技术对其结构特征进行测试与分析,并结合热处理实验探讨其颜色成因。宣化“战国红”玛瑙在正交偏光显微镜下主要有长纤维状结构、短纤维状结构、球粒状结构和晶质石英等。扫描电子显微镜图像显示晶粒大小约为0.5~5.0μm,晶粒呈大小不一的片状紧密堆积。能谱仪测试表明宣化“战国红”的主要成分为SiO2,并含有Fe、Al、Mg、Na、K、Ca等元素。结合拉曼光谱测试可知,红色条带可见较强的赤铁矿吸收峰,黄色条带可见较强的针铁矿特征吸收峰。对“战国红”玛瑙在200、300、400℃温度下进行热处理,热处理后玛瑙透明度下降,表面干涩,随着加热温度的升高,黄色条带中红色调越来越明显,400℃时黄色完全变成红色,这是由针铁矿失水转化为赤铁矿所致。结合拉曼光谱测试与热处理实验可知宣化“战国红”玛瑙红色主要由赤铁矿致色,黄色主要由针铁矿致色。     

Comparative analysis of phytochemicals and polar metabolites from colored sweet potato (Ipomoea batatas L.) tubers

Food Science and Biotechnology - We determined the phytochemical diversity, including carotenoids, flavonoids, anthocyanins, and phenolic acids, in sweet potatoes (Ipomoea batatas L.) with...     

Influence of Strontium Addition on Microstructure and Mechanical Properties of an Al–10Si–5Cu Alloy

The microstructure and mechanical properties of Al–10Si–5Cu cast alloys with micro-addition of alloying elements (V, Cr and Ni) were studied before and after strontium addition. Samples were examined using the X-Ray diffraction, the optical microscope, the scanning electron microscope and the energy dispersive spectrometer. The results indicated that the α-Al matrix, eutectic Si phase and Al₂Cu phase were the main constituent phases of Al–10Si–5Cu alloys before or after strontium addition. Strontium addition affected the refining of the α-Al grains and transforming the configuration of interdendritic phases. The un-modified alloy showed a brittle nature because of existing brittle and aggregated AlSiMnFe phases. Contributing to the alteration of microstructure in strontium modified alloy, the strength and elongation of the alloy were improved. In addition, the fracture mechanism and crack propagation process were investigated in both the alloys.     

上扬子地块黔北坳陷及周缘水文地质-地球化学特征与油气保存

从地下水化学-动力学角度对上扬子地块黔北坳陷及周缘油气保存条件进行了研究。结果表明：黔北坳陷及周缘自震旦纪以来共经历了3次重要的水文地质旋回,即加里东期、海西期-印支期和燕山期-喜马拉雅期。黔北坳陷及周缘在加里东期和海西期-印支期是两次主要的油气成藏期,但加里东末期和燕山期-喜马拉雅期运动使得区内原已形成的油气藏几乎被破坏殆尽。多次构造运动和多期大气水下渗作用使得现今黔中隆起埋深小于2 500 m、黔北坳陷埋深小于3 000 m的地层水矿化度低,处于自由交替带且底界尚不清楚,油气保存条件较差;川南坳陷在埋深800 m的浅部地层已进入交替阻滞带,油气保存条件相对较好。     

FS-ZD再启动控制器在胜利炼油厂的应用

FS-ZD再启动控制器属防"晃电"模块的一种,它可在一定时间范围内实现电动机的再启动过程,有效的保证生产的连续性。应用结果表明,该设备可提高生产装置相关电气设备的平稳运行水平,减轻晃电事故对装置安全生产的影响。     

乙醇汽油中添加剂及最佳乙醇比例的研究

参照ASTM D6422-99方法对12种单质型乙醇汽油添加剂对乙醇汽油相分离温度的改善效果进行了实验研究,筛选出9种可以使乙醇含量为10%(E10)的乙醇汽油相分离温度降低到-25℃以下的添加剂.在此基础上,采用正交实验法开发出6种复合添加剂,均可使E10乙醇汽油的相分离温度低于-30℃(添加剂用量为3%).并通过实验确定,当乙醇汽油中乙醇比例达到20%时,不加添加剂也可使其相分离温度在水含量为0.8%时低于-28℃,远高于国标中对乙醇汽油水含量的限制,有利于乙醇汽油的推广.