湿炼及油浸提两种方式对猪油品质的影响

以猪背脂为原料,采用110、120、130、140℃湿炼及油浸炼制猪油,测定了猪背脂出油率以及油脂的水分含量、酸价、丙二醛含量、过氧化值等理化指标,研究两种加工方式对猪油品质的影响.结果表明:在同一炼制温度条件下,达到最大出油率的时间湿炼比油浸提明显延长;随炼制温度提高出油率上升,140℃条件下的猪油提取率达到最高,为69%;除140、110℃湿炼外,其他加工条件所得猪油均达到国家一级食用猪油标准.     

地质统计学反演技术在薄储层预测中的应用

以厄瓜多尔南部H-N油田M1层薄储层为例,阐述了研究区M1层储层预测难点和存在问题,提出针对性的储层预测方法技术。经过储层和围岩地球物理特征分析,论证了储层预测条件,确定了运用以地质统计学反演为核心的储层预测技术对该区进行储层预测研究,来解决该区储层薄(1~25 ft)、横向变化大、隐蔽性强的薄储层的识别;通过以地震、稀疏脉冲反演、地质统计学反演不同数据体间砂体进行对比分析,精细解释出该区砂体分布;经过无井、盲井和新钻井校验,实现了薄层的高精度预测,提高了预测精度(垂向分辨率达到5 ft)。该预测结果经过在H-N油田的实际应用和新钻井钻探证实,砂层钻遇率为100%,钻探符合率达82%,实现了该区新井产能的突破。     

P2P网络中基于随时间推移的风险值评估的信任管理模型

针对现有的对等(P2P)网络信任管理模型中存在的问题:忽视短期交易时间与长期交易时间对信任值的不同影响以及缺少对交易对象资源的具体风险分析,在现有信任管理模型的基础之上,以不同用户对同一种类资源所提供的资源品质和风险作为关注点,引入风险值评估的概念,建立了基于随时间推移的风险值评估的信任管理模型。仿真结果表明,该模型使得恶意节点的行为得到有效控制,对交易资源的分析量化更加深入,进一步有效地帮助用户筛选出最优的交易者。     

一种增量式学习的语音字典构造方法

爆炸式增长的语音数据为存储与传输带来极大困难,现有方法难以实时应对海量语音频域数据.因此本文提出一种增量式学习的语音字典构造方法,该方法先将语音时域信号经短时傅里叶变换处理后转换为各窗频谱幅值,再将高维空间向量投影到低维空间,并以字典中的少数基向量线性拟合当前窗向量.进而通过存储基向量的标识和拟合系数完成对当前窗向量的存储,把无法拟合的窗向量经处理后加入字典,实现增量式学习.解压过程依据用户请求将字典中指定条目经线性拟合实现.实验结果表明,本方法能大幅度压缩语音频谱包络,适用于受带宽限制下实时高采样率的流式语音数据,与同类算法相比,在保证还原质量的情况下,能对信号的存储空间以及传输带宽进行大幅度的压缩.     

不同酵母和氮源对笃斯越橘果酒香气的影响

采用顶空固相微萃取与气相色谱-质谱联用技术,对不同酵母和氮源发酵的笃斯越橘果酒中的香气成分进行分析。结果表明,4?种果酒中共检测出86?种香气成分,包括酯类32?种、醇类18?种、萜烯类13?种、酸类10?种、醛酮类7?种,以及其他类6?种,有78?种香气成分是4?种酒共有的。添加不同酵母和氮源种类导致笃斯越橘果酒在香气化合物的种类和含量呈现出一定的差异性;采用酵母Red?Fruit和补充氮源磷酸氢二铵会促进笃斯越橘发酵进程,且果酒中异戊醇、异丁醇、乙酸乙酯以及乙偶姻等香气化合物含量较多,因此选择适宜的酵母和氮源会提升笃斯越橘果酒的香气。     

基于层次分析法的室内空气质量因素研究

为解决室内空气质量安全问题,分析了人、物以及环境3个总指标中的8项因素,确定因素的等级划分,采用层次分析法对室内环境质量安全进行评价。综合考虑确定影响室内空气质量安全的人的因素、物的因素、环境的因素为影响室内环境质量安全的主要因素,在此基础上把复杂因素看作一个系统。通过分析影响室内空气因素的特征属性、信息来源,划分出相互联系的有序层次,将决策经验量化,互相比较各因素间重要度,构造判断矩阵,计算得出基本指标的重要度并进行一致性检验。结果表明:二氧化碳、二氧化硫、氮氧化物为权重排序前三的影响因素。     

Vapor-deposited iron sulfide films as a novel hydrogen permeation barrier for steel: Deposition condition,defect effect,and hydrogen diffusion mechanism

Hydrogen embrittlement is a serious problem in the oil/gas industry. In this work, various iron sulfide (FeS) films, including iron monosulfide (FeS), pyrite (FeS₂), and pyrrhotite (Fe₇S₈), were synthesized in X80 steel by chemical vapor deposition at 200 °C, 300 °C, 400 °C, and 500 °C. The corrosion resistance and hydrogen permeation properties of the FeS films were investigated through electrochemical methods. Results indicated that FeS films significantly improved the hydrogen barrier properties of the X80 steel, which was closely related to the crystal structure type and defects of FeS films. Defects like microcracks and pinholes during deposition can increase the porosity of the film, resulting in the film properties decreased. Moreover, FeS film (at 300 °C), which had the smallest apparent hydrogen diffusivity (D ? 2.64 × 10^?7 cm²/s) and apparent subsurface concentration (C_app ? 1.12 μmol/cm³), had the best hydrogen barrier properties. The corrosion resistance of FeS film (300 °C) was excellent.     

基于热弹流模型的柴油机连杆小头轴承润滑研究

以某直列6缸柴油机为研究对象,建立活塞销-连杆-曲柄销柔性多体动力学分析模型。基于热弹性流体动力学(TEHD)润滑和微凸峰接触理论,建立连杆小头轴承的TEHD模型,分析了热负荷影响下轴承间隙和表面粗糙度对润滑性的影响规律。研究结果表明:计及热负荷影响,轴承最大油膜压力增加7.5%,最小油膜厚度降低8.1%,摩擦功耗增加10.1%,粗糙峰接触增加6.0%,轴承产生温升现象,最大温升为20.1℃;轴承间隙增加,轴承最大油膜压力增幅提高50%,最小油膜厚度减幅保持不变;表面粗糙度增加,轴承最大油膜压力增幅提高50%,最小油膜厚度减幅缩小55%。该热弹流模型研究方法为动力机械热负荷条件下摩擦副失效机理分析提供了一种可行的途径,研究结果对摩擦副滑动轴承加工精度制定具有一定的指导作用。     

Experimental Study of a Tailings Impoundment Dam Failure Due to Overtopping

The disastrous impact of a tailings dam failure is more far-reaching than that of a water retention dam failure. This paper analyzes the movement characteristics of mudflow during a tailings dam failure using physical models based on the Wadugou tailings impoundment. The physical models were built according to the similarity laws to investigate an overtopping dam failure under natural conditions and when additional protective measures were used. Based on the experimental results, the dam breach size, the breach flow discharge, flow velocity, downstream inundated area, and tailings deposition volume are all reduced by preferably protecting and maintaining the tailings dam embankment to mitigate the destructive effects of a potential dam failure. Finally, the time required for safe evacuation for the Wadugou tailings impoundment area is given.     

Effects of ultrasound on the physicochemical properties and microstructure of salted‐dried grass carp (Ctenopharyngodon idella)

Ultrasound treatment was used for accelerating drying process and shortening drying time of salted‐dried grass carp, in parallel with evaluation of physicochemical properties and microstructure. The grass carp blocks were salted with ultrasound‐assisted treatment at 0–480 W, 40 kHz for 120 min, then put into heat pump dryer for drying at 50% humidity, 30 °C for 50 hr. The moisture content results showed that ultrasound treatment could significantly promote water loss rate. As the ultrasound power increased, the hardness, the relative content of monounsaturated fatty acid and polyunsaturated fatty acid and total content of free amino acid decreased while the saturated fatty acid and sensory scores increased, respectively. Furthermore, microstructure of the dried‐salted grass carp was studied using paraffin sections and the scanning electron microscope to understand the change of microstructure. In general, ultrasound‐assisted salting significantly increased drying rate, and improved the quality of salted‐dried grass carp. This study shows the potential application of ultrasound in food drying process.

Practical applications

The ultrasound was applied in order to facilitate the traditional process to produce salted‐dried grass carp. And physicochemical properties and microstructure of salted‐dried fish were measured. The results showed that the application of ultrasound could significantly promote the mass transfer of water and improved the product's appeal for customers. The outcome of this study demonstrated a method for producing better quality dried‐salted fish products with a fast speed in the future and showed a great potential of ultrasound in food drying process.