共轭亚油酸对猪生产性能和胴体品质的影响     

艾薇 《保山师专学报》2006,25(2):25-28

对近年来有关共轭亚油酸在猪营养上的研究与应用进展进行综述,介绍了共轭亚油酸在猪生产上的应用,重点论述了共轭亚油酸对猪的生产性能和胴体品质的影响,以及分析了上述作用的潜在机制.  相似文献   

柠檬酸改性竹屑吸附亚甲基蓝的动力学和热力学分析   总被引：1，自引：0，他引：1  

龚新怀  卢小露  林维昇 《宜春学院学报》2012,34(8):47-50

为拓宽竹材剩余物的开发应用新途径。以竹屑为原料,柠檬酸为改性剂,制备了柠檬酸改性竹屑吸附剂,以亚甲基蓝（MB）为吸附对象,考察了pH、时间、吸附剂投量及吸附温度等对吸附剂吸附MB效果的影响,并对其吸附动力学和热力学进行了分析。结果表明：溶液pH增大,吸附剂对MB的吸附量增大,pH在5-9间变动,吸附剂对MB吸附量变化不大;染料初始浓度和吸附温度增加,吸附剂对MB吸附能力增强;在吸附120min,吸附达到平衡,吸附动力学过程符合二级动力学模型,吸附热力学过程符合Langmuir模型;在25℃、35℃、45℃时,吸附剂对MB的最大吸附量分别为106.38 mg/g、121.95 mg/g和125mg/g;竹屑吸附剂对MB的吸附过程是一个吸热的自发过程。  相似文献   

改性活化硅酸处理低温低浊水的应用研究     

陈亚萍 《杨凌职业技术学院学报》2012,(4):7-9

通过对难于处理的低温低浊水进行投加助凝剂改性活化硅酸进行试验研究,提出了改性活化硅酸使用中的最佳粘度、最佳投加量等具体参数;同时在试验中了解到改性活化硅酸活化时间短,保存时间长,助凝效果好,投药量少等最优性能。  相似文献   

A Three-Tier Diagnostic Test to Assess Pre-Service Teachers’ Misconceptions about Global Warming,Greenhouse Effect,Ozone Layer Depletion,and Acid Rain     

Harika Ozge Arslan  Ceyhan Cigdemoglu  Christine Moseley 《International Journal of Science Education》2013,35(11):1667-1686

This study describes the development and validation of a three-tier multiple-choice diagnostic test, the atmosphere-related environmental problems diagnostic test (AREPDiT), to reveal common misconceptions of global warming (GW), greenhouse effect (GE), ozone layer depletion (OLD), and acid rain (AR). The development of a two-tier diagnostic test procedure as described by Treagust constitutes the framework for this study. To differentiate a lack of knowledge from a misconception, a certainty response index is added as a third tier to each item. Based on propositional knowledge statements, related literature, and the identified misconceptions gathered initially from 157 pre-service teachers, the AREPDiT was constructed and administered to 256 pre-service teachers. The Cronbach alpha reliability coefficient of the pre-service teachers’ scores was estimated to be 0.74. Content and face validations were established by senior experts. A moderate positive correlation between the participants’ both-tiers scores and their certainty scores indicated evidence for construct validity. Therefore, the AREPDiT is a reliable and valid instrument not only to identify pre-service teachers’ misconceptions about GW, GE, OLD, and AR but also to differentiate these misconceptions from lack of knowledge. The results also reveal that a majority of the respondents demonstrated limited understandings about atmosphere-related environmental problems and held six common misconceptions. Future studies could test the AREPDiT as a tool for assessing the misconceptions held by pre-service teachers from different programs as well as in-service teachers and high school students.  相似文献   

无机高分子混凝剂聚硅硫酸铁处理印染废水的试验研究     

聂丽君  史博 《茂名学院学报》2010,20(1):18-20

采用一步法自行研制无机高分子混凝剂——聚硅硫酸铁（PSPFs）,采用正交试验法,通过对印染模拟废水的混凝试验,确定合成PSPFS的最佳条件是：Fe／Si摩尔比为1：1;活性硅酸聚合时间为10m／n;反应时间为10min;反应温度为90℃。用PSPFS处理模拟印染废水和实际印染废水的实验表明,PSPFS对印染废水色度具有较好的去除效果,而且优于商品PAC。  相似文献   

心率和血乳酸在中长跑训练中的应用     

李卫宁  巩清波  吴洪波 《湖北体育科技》2007,26(6):662-664

心率作为反映运动强度和生理负荷量的生理指标以实用性易测性等特点在运动中被普遍应用.但是心率极易受许多因素影响,因此影响到心率监控和评价的可靠性.乳酸是人体供能体系中的一个重要中间产物,运动时乳酸生成和乳酸清除的代谢变化是掌握运动强度的灵敏指标.通过心率与血乳酸结合的新角度提供一种利用无氧阈心率指导运动训练的方法.  相似文献   

Heuristic Reasoning in Chemistry: Making decisions about acid strength     

LaKeisha McClary 《International Journal of Science Education》2013,35(10):1433-1454

The characterization of students’ reasoning strategies is of central importance in the development of instructional strategies that foster meaningful learning. In particular, the identification of shortcut reasoning procedures (heuristics) used by students to reduce cognitive load can help us devise strategies to facilitate the development of more analytical ways of thinking. The central goal of this qualitative study was thus to investigate heuristic reasoning as used by organic chemistry college students, focusing our attention on their ability to predict the relative acid strength of chemical compounds represented using explicit composition and structural features (i.e., structural formulas). Our results indicated that many study participants relied heavily on one or more of the following heuristics to make most of their decisions: reduction, representativeness, and lexicographic. Despite having visual access to reach structural information about the substances included in each ranking task, many students relied on isolated composition features to make their decisions. However, the specific characteristics of the tasks seemed to trigger heuristic reasoning in different ways. Although the use of heuristics allowed students to simplify some components of the ranking tasks and generate correct responses, it often led them astray. Very few study participants predicted the correct trends based on scientifically acceptable arguments. Our results suggest the need for instructional interventions that explicitly develop college chemistry students’ abilities to monitor their thinking and evaluate the effectiveness of analytical versus heuristic reasoning strategies in different contexts.  相似文献   

补充谷氨酰胺对间歇性运动中血液LA、LDH等指标的动态影响   总被引：6，自引：0，他引：6  

严翊  田野  赵君军  丘卫  林燕 《北京体育大学学报》2004,27(1):46-49

通过两次用留置针对广东省田径队7名优秀男子短跑运动员连续采血7次,观察1)人体从事间歇性运动过程中血乳酸、乳酸脱氢酶、血气指标的动态变化规律;2)口服谷氨酰胺对人体从事间歇性运动过程中血乳酸、乳酸脱氢酶、血气指标的动态影响.结果发现:1)在三组间歇运动中每组血乳酸均较前一组有显著性增加.运动后6小时,乳酸就可恢复到运动前水平.LDH的变化趋势与血乳酸相似.血乳酸与血气指标的变化具有高度负相关(r＝-0.90).伴随着血乳酸的增加,血液缓冲能力下降;2)在间歇运动中伴随着血乳酸的增加,血液缓冲能力下降.外源性补充谷氨酰胺可以提高间歇运动中LDH活性,减少乳酸生成,增强血液缓冲能力,发挥缓解体内代谢性酸中毒的作用.  相似文献   

活性炭吸附酸性铬蓝 K 的研究简     

王冬华 《渭南师范学院学报》2014,(3):29-32

以小麦秸秆为原料。通过复合物理活化法制备高比表面积活性炭．用所得活性炭为吸附剂,研究了其对酸性铬蓝K的吸附行为,考察了吸附剂用量、pH值、初始浓度、温度与吸附时间对酸性铬蓝K的吸附容量与脱除效果的影响．结果表明。酸性铬蓝K在浓度50g／m^3、pH为2．02、温度320K、吸附剂用量0．1g与吸附时间40min时去除率达到99．9％．  相似文献   

小荚蛏软体部不同生理阶段脂肪酸的组成与变化     

吴爱春  ;张永普  ;应雪萍  ;贾守菊 《温州大学学报(社会科学版)》2009,(4):19-23

采用气相色谱仪测定了小荚蛏不同生理阶段（配子发生期、成熟期和排放期）软体部脂肪酸的组成．结果表明,小荚蛏软体部含有23种脂肪酸,其中饱和脂肪酸（SFA）5种,单不饱和脂肪酸（MUFA）5种,多不饱和脂肪酸（PUFA）13种．各生理阶段的SFA、MUFA和PUFA含量差异极显著,23种脂肪酸除C20：3含量无显著差异外,其余22种脂肪酸含量差异均显著;SFA含量以排放期为最高,配子发生期为最低;MUFA含量在配子发生期高于成熟期和排放期,PUFA含量在配子发生期和成熟期高于排放期．  相似文献