四川省水资源可利用量与承载力初探

为了科学合理规划指导水资源的开发利用,根据四川省国民经济发展规划及各行业耗水情况,采用倒算法估算了四川省水资源的可利用量,并分析了各分区的水资源承载能力。从总量上看,四川省水资源可以满足社会经济发展的需求,但由于水资源分布与国民经济产业分布不匹配,部分地区还存在工程性缺水问题。为此,提出了积极建设全省水资源配置骨干网络,加快骨干水利工程建设,加大节水型社会建设力度等措施,以保障四川经济社会可持续发展。     

热处理工艺对ER7车轮钢力学性能的影响

ER7车轮钢经不同工艺热处理后,可获得珠光体片层间距以及铁素体含量不同的显微组织,并对不同工艺处理试样的拉伸性能及-20℃冲击性能进行了测试.结果表明,随冷却速度的增大,车轮钢铁素体含量增加,珠光体片间距和珠光体球团尺寸减小.增大冷却速率,会使车轮钢的屈服强度、抗拉强度、伸长率和断面收缩率都随之增加.随着珠光体片间距和...     

四种胺类捕收剂体系中两相泡沫和赤铁矿/石英三相泡沫的稳定性

选取赤铁矿和石英两种纯矿物,十二胺、十二烷基三甲基氯化铵、GE609、N-十二烷基乙二胺四种胺类捕收剂,研究了不同pH值和捕收剂浓度对两相泡沫稳定性的影响以及不同粒级的赤铁矿和石英对三相泡沫稳定性的影响。结果表明,除N-十二烷基乙二胺外,其余三种胺类捕收剂溶液的泡沫半衰期均随着捕收剂浓度的增加呈现先升高后降低的趋势,且泡沫稳定性总体呈现酸性>中性>碱性的规律。N-十二烷基乙二胺的泡沫半衰期随浓度的增加逐渐升高,泡沫稳定性呈现碱性>中性>酸性的规律;在四种胺类捕收剂体系中,加入不同粒级石英或者赤铁矿颗粒后均能够在一定程度上提高泡沫的稳定性,颗粒粒度越细,泡沫越稳定,-18μm粒级石英颗粒的影响尤为明显;石英提高泡沫稳定性的程度远高于赤铁矿,加入细粒级的石英颗粒能够大幅度提高泡沫稳定性。微细粒级石英是急剧提高胺类捕收剂浮选泡沫稳定性的关键因素。     

Antioxidant power,lipid oxidation,color, and viability of Listeria monocytogenes in beef bologna treated with gamma radiation and containing various levels of glucose

Ionizing radiation can be used to pasteurize ready-to-eat (RTE) meat products. Thermal processing of RTE meats that contain dextrose results in the production of antioxidants that may interfere with ionizing radiation pasteurization of RTE meat products. Beef bologna was manufactured with dextrose concentrations of 0, 2, 4, 6, and 8%. Antioxidant activity, as measured by the Ferric Reducing Antioxidant Power assay, increased with dextrose concentration but was unaffected by ionizing radiation. Lipid oxidation increased significantly in irradiated bologna (4 kGy) that contained dextrose. Hunter color analysis indicated that the addition of dextrose reduced the ionizing radiation-induced loss of redness (a-value) but promoted the loss of brightness (L-value). The radiation resistance, D10-value, of Listeria monocytogenes that was surface-inoculated onto bologna slices was not affected by dextrose concentration. L. monocytogenes strains isolated from RTE meats after listeriosis outbreaks were utilized. Increased antioxidant activity generated by thermal processing of dextrose in fine emulsion sausages does not present a barrier to radiation pasteurization of RTE meats. However, a high dextrose concentration in combination with gamma irradiation increases lipid oxidation significantly.     

纸浆模塑专用蜡的研制

为解决纸浆模塑制品真空吸附成型过程制品和模具的相粘问题,以改性蜡为原料,以复合乳化剂对其进行乳化,在一定工艺条件下制备出了纸浆模塑专用蜡。以乳液粒径为评价指标,选择乳化剂的加入量为考察因素,利用正交实验L9(33)筛选出复合乳化剂的最佳配比为:乳化剂E4加入量为3.5%、乳化剂E5加入量为3.6%、助乳化剂EA加入量为0.8%。考察了操作特性对乳液性能的影响,确定出最佳的乳化工艺条件为:搅拌速度1 000～1 600 r/min、乳化时间10～30 min、乳化温度85～95℃及固含量28%时用水相加入油相的方法、当固含量28%时采用油相加入水相的方法。据此所制得的乳液粒径0.1μm,其稳定性能很好,放置90 d以上不分层。产品的性能评价表明:研制的纸浆模塑专用蜡对纸质模塑材料成型润滑具有明显的效果,脱模效果好、产品成品率高、提高了生产效率。     

光伏废料制备Si3N4-SiC材料的抗氧化性和抗侵蚀性

将光伏废料经酸洗除杂后,与硅粉按85∶15的质量比配料,以聚乙二醇做结合剂,成型为10 mm×10 mm×20 mm的生坯后,在1380℃保温2 h氮化制成Si3N4-SiC材料,然后研究了该Si3N4-SiC材料的抗氧化性和抗侵蚀性。结果表明:1)制备的Si3N4-SiC材料在空气气氛中抗氧化性较好,主要是由于其氧化产物Si2N2O和SiO2填充气孔,促进烧结,提高了试样的致密度。2)在静态熔盐(Na3AlF6)中的抗侵蚀性能较好,主要是由于Na3AlF6渗入气孔中,使其显气孔率降低。3)在动态熔盐中的抗侵蚀性相对变差,主要是由于CO2气体的搅拌和对Si3N4、SiC的氧化二者共同作用的结果。     

135MW机组给水泵及其系统节能改造的研究与实践

对 1 35MW机组给水泵及其系统存在的泵运行效率低、出力不够、通流部分匹配不合理等问题进行了分析 ,提出了针对这些问题进行给水泵改造的主要技术措施。通过试验 ,选择了适当的给水泵设计参数 ;研究了给水泵的通流部件的最佳匹配 ;对叶轮和导叶型线进行了重新设计。最后分析了改造前后给水泵的性能比较、节能效果和经济效益     

降低富氧条件下汽油机NOX排放技术方案分析

稀燃技术由于可以改善发动机的经济性和排放已越来越受到人们的重视。然而，由于稀燃的富氧燃烧，使得N0x降低较小。本文介绍并分析了国内外降低富氧下稀燃汽油机N0x排放的几种技术。     

铸铁中最大石墨尺寸估计与疲劳强度预测

利用SEV极值统计方法预测不同体积的铸铁中最大石墨尺寸,进而预测疲劳强度。研究结果表明,随着母体体积的增大,预测的最大石墨尺寸增大,而疲劳强度降低。     

Quality of Fresh-cut Apple Slices as Affected by Low-dose Ionizing Radiation and Calcium Ascorbate Treatment

ABSTRACT: Although ionizing radiation effectively inactivates food-borne bacterial pathogens in fresh-cut fruits and vegetables, it may adversely affect product quality. In this study, the effects of calcium ascorbate (CaA) and ionizing radiation on quality of 'Gala' apple slices under modified atmosphere packaging were investigated. 'Gala' apple slices, treated with water or 7% CaA followed by either nonirradiation (0 kGy) or irradiation at 0.5 and 1.0 kGy, were stored at 10°C for up to 3 wk. The titratable acidity, pH, firmness, ascorbic acid content, color, and microflora population were measured weekly throughout storage. Irradiation did not affect titratable acidity and pH of sliced apples. Fruit slices softened during irradiation and storage, but this decrease in firmness during storage was reduced by the CaA treatment. Although the ascorbic acid content of apple slices treated with CaA decreased rapidly during storage, the ascorbic acid content was always higher in those treated samples than in the apple slices treated with water. Irradiation decreased both L * and hue values of apple slices. Hue values decreased during the entire storage period while L * increased during the 1st wk of storage, then decreased between 1 to 3 wk of storage. CaA increased L * and hue values of apple slices, suggesting CaA reduced browning, even in irradiated samples. The microflora population of apples slices was not affected by CaA, and CaA treatment did not alter the reduction in microflora by irradiation. The combination of CaA and irradiation enhanced microbial food safety while maintaining quality of fresh-cut apple slices.