生物破乳剂产生菌XH-1的发酵动力学

为了优化生物破乳剂生产的发酵过程,提高生物破乳剂的产量,对破乳剂产生菌Bacillus mojavensis XH-1的分批发酵过程进行了研究.根据破乳剂产生菌XH-1发酵过程的特点,在Logistic方程和Luedeking-Piret方程的基础上,建立了菌株XH-1发酵过程中菌体生长、基质消耗和蛋白类破乳剂形成的动力学方程.采用Origin 7.5软件对试验数据进行处理,得到了破乳菌XH-1的分批发酵动力学模型参数.结果表明:模型预测值和试验值吻合较好,所建立的方程能较好地预测其实际发酵过程,具有很好的适用性,对生物破乳剂的发酵生产具有一定的指导意义.     

黄土地区通过联合测定法确定界限含水率的商榷

黄土和黄土状土大多数为粉土,是工程建设经常遇到的土类之一,界限含水率是决定黄土性质的一个重要指标,对黄土的定名分类、划分状态、评价承载力、估计最优含水率、估算土的力学性质都有重要的意义。而联合测定法是确定界限含水率的重要途径,因此,探讨联合测定法的适用性具有重要的工程意义。     

浅谈数据挖掘

数据挖掘所得到的信息应具有先前未知、有效和可实用3个特性。文章简单介绍了数据挖掘技术、功能特性及它的实际应用。     

基于PIC16F873A的步进电机远程控制

PIC系列单片机是美国Microchip公司生产的高性能价格比的标志产品,CPU采用RISC结构.分别仅有33,35,58条指令,采用Harvard双总线结构,运行速度快,低工作电压,低功耗,较大的输入输出直接驱动能力,价格低,小体积.在办公自动化设备,消费电子产品、电讯通信、智能仪器仪表、汽车电子、金融电子、工业控制不同领域都有广泛的应用.     

蕨麻饮料的研制

采用野生植物蕨麻（Potentilla anserinaL.),配以胡萝卜,用正交试验得出蕨麻饮料配方的最佳组合。     

Preliminary evidence indicating Dome A （Antarctica） satisfying preconditions for drilling the oldest ice core

Lowest temperature and snow accumulation rate are preconditions for retrieving the oldest ice core from the polar ice sheets. The 10-m depth firn temperature at Dome A, the summit of the Antarctic Ice Sheet, recorded by an automatic weather station （AWS） was -58.3℃ in 2005 and -58.2℃ in 2006, respectively. The 10-m firn temperature is an approximation of the annual mean air temperature （AMAT）, and this is the lowest AMAT that has been recorded on the surface of the Earth. The stable isotopic ratios （δ^18O and δD） of surface snow at Dome A are also lower than at other ice sheet domes along the East Antarctic Ice Divide such as Dome C, Dome F, Dome B and Vostok. These facts indicate that Dome A is the ＂pole of cold＂ on the Earth. The total amount of snow accumulation rate in 2005 and 2006 was only 0.16 cm, equaling 0.016 m water equivalent per year, the lowest precipitation ever recorded from Antarctica. Preliminary evidences indicate that Dome A is a candidate site for recovering the oldest ice core.     

快变信道下OFDM系统的判决反馈信道估计

为了改善OFDM系统在快变信道下的传输性能,文中提出一种利用叠加训练序列进行时域信道估计的方案.基于时变信道抽头系数的指数基插值模型,利用一个符号内的叠加周期训练序列建立线性表达式,并根据最小二乘准则求出插值模型的相应参数,由此构造对应的时域响应矩阵和频域均衡矩阵.为进一步改善估计和均衡性能,将所得的符号判决作为已知的训练序列进行迭代信道参数估计,从而能有效地改善信道估计的性能并消除载波间干扰.实验结果表明文中算法在时间-频率双选择性信道下具有较好的性能.     

Novel concept of recycling sludge and dust to BOF converter through dispersedin-situ phase induced by composite ball explosive reaction

Recycling of iron and steelmaking dusts is a key issue in environmental protection efforts and to ensure efficient utilization. In this investigation, we developed a novel recovery process that uses a dispersedin-situ phase induced by an explosive reaction of composite balls of iron and steelmaking dusts. We designed and prepared composite balls for this function using a laboratory model batch-type balling disc (at 12 r/min) and optimized the feeding modes in 180-t and 260-t basic oxygen furnace (BOF) converters. The results indicate that feeding composite balls into BOF converters is an effective novel technology for recovering iron and steelmaking dusts. The period after hot metal charging and prior to the oxygen-blowing process is the most reasonable time to feed composite balls. Composite ball treatment is not appro-priate for steel production with sulfur requirements lower than 80 ppm. The maximum composite ball feeding amount is 40 kg/t and the iron yield rate is better than 95%. Compared with the conventional recycling process of sludge and dust, this novel technology is more convenient and efficient, saving up to 309 RMB per ton of steel. Further investigation of this novel recycling technology is merited.     

太原粉质粘土工程性质指标概率特征的分析和研究

以太原地区典型土层－粉质粘土为代表,根据２０个工程的勘察资料及室内一系列强度试验,对该地区粉质粘土工程性质指标的概率统计特征进行了研究探索,得出了其土性指标变异系数的变化规律和土的变异类型,建立了其设计参数的Ｂｅｔａ分布概率模型,拟合了其指标间的经验关系。