半微量重氮盐制备及偶合反应实验研究和体会

阐述了半微量重氮盐制备及偶合反应实验改进的出发点、操作及教学实践体会     

二次酸浸法提取煤灰中的氧化铝(英文)

目的:煤灰渣酸浸提铝通常效率不高,主要因为灰渣中存在含铝晶体矿物(如莫来石、尖晶石和长石等)。为解决含铝晶体不易与硫酸反应的问题,本文提出二次酸浸提铝法。创新点:基本实现铝硅分离,第一步酸浸实现非晶态铝的浸出,残渣经焙烧和水浸后,第二步酸浸实现剩余铝的浸出。方法:1.一次酸浸时,硫酸直接与煤灰渣反应浸出部分氧化铝,提铝残渣加碳酸钠焙烧后,含铝晶体遭到破坏;2.焙烧产物经水浸溶解出硅酸钠,水浸残渣做X射线衍射分析表明其主要为铝硅非晶体活性物质,此时可用硫酸在温和条件下浸出剩余的铝。结论:1.一次酸浸提铝在10 mol/L硫酸、120°C、2 h和1:2固液比的条件下,铝浸出率为81.72%;2.用5 mol/L硫酸二次酸浸时,20°C下铝浸出率已经达到87.31%,100°C下更是达到99.06%;3.综合两次酸浸结果,铝的浸出总效率在97%以上。     

The Mismatch between Students’ Mental Models of Acids/Bases and their Sources and their Teacher’s Anticipations thereof

The aim of this study is to compare the characteristics and sources of students’ mental models of acids and bases with a teacher’s anticipations and, based on this comparison, to explore some possible explanations why motivated students might fail to learn from a subject‐knowledgeable chemistry teacher. The study involves a chemistry teacher and her 38 ninth graders and focuses on the mental models of three high achievers and three low achievers who were interviewed in depth. Four students’ mental models of acid and base are identified. The mental models and sources of students’ conceptions of acids and bases that influenced the high achievers are compared to those of the low achievers. We find that the teacher in the study made accurate anticipations of her students’ mental models in the case of the high achievers but inaccurate anticipations of the low‐achievers’ mental models and the diverse sources influencing their mental models. In addition, the teacher incorrectly attributed the poor achievement of the low‐achieving students to their intuition and underestimated the effects of her teaching on the achievement of these students. As a result, the teacher’s instruction reinforced the low‐achievers’ incorrect mental models. Finally, the different approaches for teaching students with different achievements are emphasized according to the empirical data in this study.     

白灵菇及杏鲍菇子实体多糖含量的测定

采用苯酚-硫酸法，用精制白灵菇、杏鲍菇多糖对葡萄糖的换算因子，对白灵菇和杏鲍菇多糖含量进行测定。结果表明，白灵菇多糖的平均回收率为98％，相对标准偏差RSD为1．76％；杏鲍菇多糖的平均回收率为96．0％，相对标准偏差RSD=4．56％．白灵菇中多糖含量为7．58％，杏鲍菇多糖含量为6．00％．     

Activity of Hydrolytic Enzymes in Various Regions of Normal Human Brain Tissue

The activity of six hydrolytic enzymes-carboxyl esterase, acid phosphatase, alkaline phosphatase, β-galactosidase, β-glucosidase and β-hexosaminidase, were studied in different regions of the normal human brain tissue obtained at autopsy. Protein estimation and activities of the hydrolytic enzymes with respective substrates were assayed by spectrophotometric and spectroflourometric methods. Amongst the eight regions of the brain-frontal, parietal, occipital, temporal, thalamus, cerebellum and hippocampus, the pineal gland showed highest activity for all hydrolytic enzymes studied except for carboxyl esterase. Among six hydrolases studied, hexosaminidase exhibited highest activity in all regions of the human brain while alkaline phosphatase activity was the least amongst all regions studied. A majority of the enzymes studied showed higher activity in gray matter as compared to the white matter except acid phosphatase and β-glucosidase which exhibited higher activity in the white matter. The most significant finding in the present study was the high activity of all hydrolytic enzymes noted in the pineal gland as compared to all other regions of the human brain. Such a finding has not been hitherto reported earlier in human brain tissue samples. If the specific activities of these enzymes are to be considered as any functional index, then pineal gland may be more metabolically active tissue with respect to the hydrolytic function as compared to the other regions of the brain.     

二氧化钛薄膜光催化降解酸性品红

采用溶胶－凝胶法在玻璃表面制得TiO2(锐钛型）薄膜，研究了以254nm的紫外线为光源，酸性品红（AF）在TiO2薄膜上的光催化降解初始速率与溶液初始浓度、初始pH值及外加氧化剂H2O2的关系。结果表明，AF的光催化降解行为采用Langmuir-Hinshelwood(L-H)模型来解释，利用TiO2薄膜作为光催化剂光降有机物AF具有较好的应用前景。     

水质高锰酸盐指数酸性法测定过程中获得因素的影响分析

根据酸性高锰酸盐指数法的分析原理和测定分析过程,高锰酸盐指数的测定结果受到分析过程中多个获得性因素的影响,分析和讨论了样品的取样量、草酸钠溶液浓度、校准系数、加热温度和反应时间、滴定温度等对测定结果的影响。为了保证样品分析结果的准确性和可比性,样品的测定过程一定要严格遵守操作规程,严格控制实验条件。     

2-噻吩甲酸（5-氟尿嘧啶-1-基）甲酯的合成、晶体结构和热性质

报道了一种新的5-氟尿嘧啶衍生物2-噻吩甲酸（5-氟尿嘧啶-1-基）甲酯的合成.用1HNMR、13CNMR、IR对其进行了结构表征,通过单晶X射线衍射确定了晶体结构,同时分析了热性质.晶体属单斜晶系,空间群为P2/c,晶胞参数为：a=9.6134（14）,b=4.8381（7）,c=24.534（4）,α=90°,β=97.289（3）°,γ=90°;Z=4,F（000）=552,R1=0.0616.     

消除肌酐测定中两种干扰因素的探讨

目的：消除血红蛋白和胆红素两种因素对碱性苦味酸速率法测定肌酐的负干扰。方法：用苦味酸速率法测定未溶血、人为溶血、人为溶血后加0．88mol／L H2O2 37℃水浴20min、人为溶血后加0．88mol／L H2O2 37℃水浴30min、未溶血加0．88mol／L H2O2 37℃水浴20min五种处理的血液样品中肌酐值。结果：其他四组与第一组差异均有统计学意义（P〈0．01）;第三组与第二组、第五组测定结果有差别（P〈0．01或P〈0．05）,而第三组与第四组的测定结果则无差别（P〉0．05）。结论：用0．88mol／L H2O2处理溶血样品后,再进行肌酐测定。可消除血红蛋白和胆红素对肌酐测定的影响,使测定结果更真实。     

乳酸指标在运动员竞技状态监控中的解读与思考

血乳酸能够较准确地反映不同运动方式及运动强度下能量系统的供能情况,并且对人体的运动能力具有明显的影响.因此,目前血乳酸水平检测被广泛用于运动训练监控,并且取得了很好的效果.本文运用文献、逻辑、归纳等方法,说明乳酸监控在运动员竞技状态中的重要作用,为教练员、管理人员把握好运动员的训练、比赛提供科学依据.