SS-1型声速实验仪的研制

本文阐述了SS—1型声速实验仪的原理、结构和测量方法。波动学和分子物理学是物理学中的重要组成部分,"声速的测量"和"Y值的测量"两个实验有助于学生对波动相位的空间分布、谐振动的合成、李萨育图、能量按自由度均分原     

Accumulation of Zinc and Molar Ratio of Phytic Acid and Zinc during Maize Grain Maturation

Dynamics of the accumulation of total ash and zinc, and their relationships with total dry matter, crude proteins and phytic acid during maize grain maturation were investigated. The investigation was carried out on normal maize hybrids grown under the same topographical and agrotechnical conditions over two consecutive vegetation years.
The amount of total ash, expressed on fresh and dry matter bases, changed significantly (P = 0.05 and P = 0.01) during grain maturation depending on maturity stage and variety. The dynamics of the accumulation of ash in fresh grain matter during maturation as well as the ash amount in dry matter of mature grains were significantly affected by environmental conditions.
The accumulation of zinc in fresh matter of developing grain was significantly affected (P = 0.05 and P = 0.01) by the degree of grain maturity and by variety, and correlates significantly (P = 0.001) and positively with the deposition of total dry matter, crude proteins as well as with phytic acid in both vegetation years.
The molar ratio of phytic acid and zinc increased significantly during grain maturation indicating a possible decrease of zinc availability.     

3M纳米树脂修复乳磨牙龋110例临床疗效分析

目的比较不同材料修复乳磨牙龋的临床疗效.方法选择患儿110例,440个乳磨牙,采用随机对照方法,应用4种不同材料对其进行充填修复.结果经过1-2 a观察,银汞合金、光固化复合树脂、玻璃离子水门汀、3M钠米树脂组修复乳磨牙龋成功率分别为61.67%,67.00%,60.63%和91.40%.结论4种材料修复乳磨牙龋各具其优缺点,以3M钠米树脂修复乳磨牙龋临床效果较好.     

甲烷水合物在冰浆中的鼓泡生成特性

以水合物的形式储运天然气具有储存压力低、安全可靠等优点,但水合物在天然气储运技术领域的应用仍然受到储气量低、生成速度慢等因素的限制。以甲烷水合物为研究对象,通过试验研究了压力、恒温浴温度、表面活性剂SDS质量浓度以及甲烷气体进气时间对甲烷水合物在冰浆中鼓泡生成的作用规律。试验压力范围为4～6 MPa,恒温浴温度范围为-1～1℃,表面活性剂SDS质量浓度范围为100～800 mg/L。结果表明:压力变化对最终的储气体积摩尔浓度影响不大;当恒温浴温度由-1℃上升至1℃时,反应持续时间缩短11.5%～17.4%,储气体积摩尔浓度降低7.4%～8.5%;适当延长进气时间,有助于缩短诱导时间,提高甲烷水合物的生成速率和最终储气体积摩尔浓度。     

脲醛树脂胶粘剂的质量控制

对影响脲醛树脂胶粘剂质量的主要因素如摩尔比、PH值、二次尿素加入点、反应温度、反应时间及原料质量等进行了分析,评价并提出最佳控制范围。     

摩尔吸光系数法测定酱渣饼和大豆异黄酮产品中总异黄酮含量的研究

根据Lambert-Beer定律,分别以12种大豆异黄酮的摩尔吸光系数为标准,利用紫外分光光度法对酱渣饼、大豆异黄酮产品进行总异黄酮含量的测定。结果表明,与目前广泛应用的紫外分光光度法、高效液相色谱法等比较,测定数据具有一定的可靠性和准确性,其优点在于不用标准样品,降低研究成本,方法简便实用。     

中缅树鼩头骨及下臼齿几何形态与环境的关系

共选取分布于云南、贵州和广西地区的190个中缅树鼩头骨和32颗臼齿(第二、第三下臼齿),运用几何形态测量法对其头骨侧面、腹面、背面及下颌侧面的形态特征进行主成分分析、薄片样条分析,同时运用统计软件SPSS15.0对头骨和臼齿进行多维尺度分析,以探讨头骨及臼齿形态与环境之间的关系.结果表明,头骨侧面在研究多种群头骨形态时更适宜,更有参考价值;经过薄片样条法分析显示形变多集中在鼻骨和臼齿,这可能与中缅树鼩生存的气候和地理环境相适应;经多维尺度分析显示云南、贵州和广西地区的中缅树鼩头骨具有明显的地区差异,同时,对臼齿的分析显示,臼齿形态具有地区差异,这种变化可能与中缅树鼩生活环境的经度和纬度有关.综上,云南、贵州和广西地区的中缅树鼩的头骨具有形态变异,并且差异仅仅发生在种群水平,这可能反映了其对特定生态环境的形态适应.     

Short‐term response of the Ca cycle of a montane forest in Ecuador to low experimental CaCl2 additions

The tropical montane forests of the E Andean cordillera in Ecuador receive episodic Sahara‐dust inputs particularly increasing Ca deposition. We added CaCl₂ to isolate the effect of Ca deposition by Sahara dust to tropical montane forest from the simultaneously occurring pH effect. We examined components of the Ca cycle at four control plots and four plots with added Ca (2 × 5 kg ha^–1 Ca annually as CaCl₂) in a random arrangement. Between August 2007 and December 2009 (four applications of Ca), we determined Ca concentrations and fluxes in litter leachate, mineral soil solution (0.15 and 0.30 m depths), throughfall, and fine litterfall and Al concentrations and speciation in soil solutions. After 1 y of Ca addition, we assessed fine‐root biomass, leaf area, and tree growth. Only < 3% of the applied Ca leached below the acid organic layer (pH 3.5–4.8). The added CaCl₂ did not change electrical conductivity in the root zone after 2 y. In the second year of fertilization, Ca retention in the canopy of the Ca treatment tended to decrease relative to the control. After 2 y, 21% of the applied Ca was recycled to soil with throughfall and litterfall. One year after the first Ca addition, fine‐root biomass had decreased significantly. Decreasing fine‐root biomass might be attributed to a direct or an indirect beneficial effect of Ca on the soil decomposer community. Because of almost complete association of Al with dissolved organic matter and high free Ca²⁺ : Al³⁺ activity ratios in solution of all plots, Al toxicity was unlikely. We conclude that the added Ca was retained in the system and had beneficial effects on some plants.     

用头骨上齿隙鉴定布氏田鼠种群年龄的研究

本文在笔者前期工作的基础上，根据布氏田鼠15项生长指标的主分量分析结果，筛选出以头骨上齿隙作为划分布氏田鼠相对年龄组客观而简便实用的指标。该鼠的头骨上齿隙没有性别差异，对雌雄鼠可采用同一标准同时划分其年龄组。通过进一步分析，将其划分为五个年龄组：幼年组的上齿隙在6．49mm以下，亚成年组为6．50～7．33mm，成年一组为7．34～838mm，成年二组为8．39～9．43mm，老年组在9．44mm以上。此外，本文尚就年龄组成及其季节变化、年龄与繁殖等方面进行了分析。     

氯甲酸乙酯尾气综合利用的研究

氯甲酸乙酯生产过程中,光气过量约5％～20％,使用氯甲酸乙酯和乙醇混合物吸收尾气,通过调节反应温度、氯甲酸乙酯与乙醇配比、反应时间,吸收尾气制得的氯甲酸乙酯含量在98％以上.