北京市冬季PM2.5中碳组分的测量与分析

使用两台较先进的仪器,Aethalometer和Sunset碳分析仪(TOT),同时同地检测北京大气PM_2.5的碳组分。实验发现：两台仪器的监测结果有较好的线性相关性和一致性(R²=0.80);EC（Elemental Carbon）和OC（Organic Carbon）有较好的线性相关性(R²=0.82);OC/EC的比值白天较夜间高、正常天气较逆温天气较高、逆温天气下白天与夜间差别不大,OC/EC平均值约4.76;并分析了用OC/EC的比值大于2判断是否存在二次污染的片面性。     

OC曲面活塞数控加工系统动态特性研究及动力修改

ＯＣ曲面活塞以其优良的性能在内燃机上获得了广泛应用．作者所在单位研制开发了振动与数控技术相结合的ＯＣ曲面活塞数控加工车床．为了提供改进设计的理论依据，对加工系统进行了动态试验和结构改进，使系统的动态性能有了明显的改善．最后进行了切削验证，证明所设计的加工设备完全可以保证零件的加工要求．     

坯布、印染布外观监督抽查中的二次抽样方案

分析了纺织品外观监督检验的特点及目前使用的一次方案的特性．按照抽检特性与一次方案相一致，而平均抽样量小于一次方案的原则设计适用于坯布、印染布外观监督检验的二次抽样方案．检验结果表明，所设计的二次方案能保证检测的可靠性，平均抽样量仅相当于原一次方案样本量的２／３～３／４．文中还指出了使用二次方案应注意的几个问题．     

纳米SiO2的制备及性能研究

 用溶胶—凝胶法制备了纳米SiO₂,考察了溶胶的浓度和pH值对凝胶时间的影响,并用FT-IR,XRD和TEM研究了其在热处理过程中的物相及显微结构.结果表明:溶胶浓度和溶胶pH值对凝胶时间影响较大.在温度为600℃时,经过烧结晶化,可制得纳米二氧化硅,其平均粒径20nm,外观形状呈球形,且热稳定性良好.     

光正交码的码字特性

研究了光正交码的自相关和互相关特性，采用差分矩阵建立计算机模型，优化了算法，并对光正交码的容量进行分析，得出容量与码长、码重和相关系数之间的内在关系．     

高速低耗BiCMOS OC门及其线与逻辑系统

为了满足高速度、低功耗数字逻辑系统的应用需求,运用改进电路内部结构和优化选取器件参数的方法,设计了4种双极互补金属氧化物半导体集电极开路（BiCMOS OC）门,并且用它们构成了线与逻辑系统;藉助两个BiCMOS OC门线与系统推导出其上拉电阻RL的计算式;对所设计的4种BiCMOS OC门和一种传统的TTL OC门线与系统进行了仿真试验和硬件电路试验．长工验数据和分析结果表明,所设计的BiCMOS OC门线与系统的电源电压均可为2．6—4．0V,工作速度与TIL OC门线与系统相接近,在60MHz测试条件下它们的功耗比TTL OC门减少4．77—5．68mW,且它们的延迟一功耗积平均降低了45．5％．     

不锈钢基板上SiO_2涂膜研究

采用溶胶一凝胶法,以Si（C2H5）4为原料在不锈钢基板上进行SiO2涂膜．该层SiO2薄膜在400℃,1min的低温下制得．通过热重一差热话图和红外光谱等研究,证明SiO2涂膜不仅稳定、均匀、纯度高,且具较高硬度和抗腐蚀性．     

微波干燥脱水污泥性质变化及分析

在不同微波功率下,干燥脱水污泥,观察其微生物形态,并分析其TN/TP/OC、挥发分性质的变化。通过显微镜观察,微波1 min时,微生物缩水;2 min时失去活性;4 min时蛋白质变性。干化污泥TN/TP/OC、挥发份受微波功率影响显著,随微波时间延长,微波功率越大,TN呈一级"波浪式"下降趋势越明显,含量从22.5 mg/g降至13.0 mg/g;TP呈二级"阶梯式"上升趋势越明显,含量从1.25 mg/g上升至1.65 mg/g;OC先下降后上升的幅度越明显,含量从26.1 mg/g降至23.6 mg/g再上升至26.6 mg/g;挥发份呈一级"阶梯式"递减趋势越明显,含量从44.7%降至33.5%。     

Isotopic composition of organic carbon and elemental carbon in PM2.5 in Hangzhou, China

In order to identify the sources of organic carbon (OC) and elemental carbon (EC) in airborne PM2.5 in Hangzhou, OC and EC were oxidized to CO2 offline in two thermal steps, and their carbon isotope compositions were measured by mass spectrometer. Results showed that the average δ13COC values were -52.8‰, -48.1‰, -50.0‰ and -52.5‰ in spring, summer, autumn, and winter, respectively, and the annual average value was -50.9‰ (-85.0‰ to -35.6‰), whereas δ13CEC values were -26.4‰, -26.9‰, -26.7‰ and -25.9‰ in the four seasons, and its annual value was -26.5‰ (-30.5‰ to -23.8‰). Large differences were found between isotope compositions of the two types of carbon. δ13COC values were much smaller than those of δ13CEC, and varied in a large range, and the ratios in both spring and winter were the smallest. δ13CEC varied in a small range, and its mean values in four seasons were nearly the same. This suggests that the carbon isotope compositions of OC and EC in PM2.5 can provide useful information in distinguishing their sources.     

Phytolith carbon sequestration in bamboos of different ecotypes: a case study in China

Occlusion of carbon （C） within phytoliths （PhytOC） is becoming one of the most promising terrestrial C sequestration mechanisms. This study explored the production of PhytOC within 35 bamboo species belonging to three ecotypes using methods of microwave digestion. The aim of this study is to explore the present and potential C sequestration rate within phytoliths of bamboo species from three ecotypes. PhytOC content in bamboos of three ecotypes ranges from 0.07 % to 0.42 %. The mean PhytOC production flux decreases as： clustered bamboo （0.050 ± 0.016 t CO2 ha^-1 a^-1） ≈ mixed bamboo （0.049 ± 0.016 t CO2 ha^-1 a^-l） 〉 scattered bamboo （0.038 ± 0.020 t CO2 ha^-1 a^-1）. The phytolith carbon sequestration in Chinese bamboo is estimated to be 0.293±0.127 Tg （1 Tg = 1012 g） CO2 a^-1; approximately 75 %, 3 %, and 22 % of which is contributed from scattered, mixed and clustered bamboo, respectively. Taking the PhytOC production flux of 0.18 ± 0.12 t CO2 ha^-1 a^-1 and current annual area increasing rate of 3 %, global bamboo phytoliths would sequester 11.9 ± 7.9 Tg CO2 a^-1 by 2050. Consequently, bamboo forests have significant potential to mitigate the increasing concentration of atmospheric CO2 by maximizing PhytOC production flux and expanding bamboos.