麝香体系结晶分离研究

研究了根据酮麝香、1,3-二甲基-2,4-二硝基-5-叔丁基苯晶体生长速度的不同,从对二者均达到饱和的溶液中分离得到1,3-二甲基-2,4-二硝基-5-叔丁基苯晶体的过程,计算了晶体生长速度并进行了实验验证。     

高速逆流色谱法分离β-谷甾醇和菜油甾醇的研究

利用高速逆流色谱法 ,并选用V(庚烷 )∶V(乙腈 )∶V(乙酸乙酯 ) =5∶5∶1溶剂体系 ,成功地分离了混合植物甾醇标准品中的 β 谷甾醇和菜油甾醇。经过HPLC检测 ,一次性分离可得到质量分数为 97%的 β 谷甾醇和质量分数为 91%的菜油甾醇产品 ,收率分别可达 5 6 %和 5 0 %。该方法简便、重现性好 ,可作为高纯度 β 谷甾醇和菜油甾醇标准品的制备分离方法     

Self‐regulation during e‐learning: using behavioural evidence from navigation log files

The current paper examined the relationship between perceived characteristics of the learning environment in an e‐module in relation to test performance among a group of e‐learners. Using structural equation modelling, the relationship between these variables is further explored in terms of the proposed double mediation as outlined by Ning and Downing. These authors initially proposed that motivation and self‐regulation strategies are mediators between the perception of the learning environment and performance. In our replication and extension study, we substituted self‐reported self‐regulation with behavioural indicators of self‐regulation using navigation log files and focused on test‐taking rather than general motivation. We proposed that navigational patterns captured using log files can also help deduce self‐regulation in e‐modules and provide information in the absence of self‐reports. Path analyses provide partial support for our navigational hypotheses and the model. Implications of our results for the use of e‐module data and conclusions based on navigation are discussed.     

Surface hydrolysis of filaments based on poly(trimethylene terephthalate) spun at high spinning speeds

The surface alkaline hydrolysis of fibers made from poly(trimethylene terephthalate) (PTT) was studied after extruding the polymer at high spinning speeds from 2000 to 6000 m/min and heat setting in the range of temperatures from 100 to 180°C. Fiber weight loss increased with an increasing heat‐setting temperature but it was also dependent on the spinning speed. Some of the partially hydrolyzed fibers had a well‐developed, hydrophilic surface, and pore size in the range of 0.69 to 1.20 μm. The optimum reaction and morphological conditions for increasing porosity in PTT fibers depends on spinning speed and heat‐setting temperature. A temperature of 180°C is the upper limit for heat‐setting PTT filaments but seems to be the most effective for making porous fibers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 1724–1730, 2004     

采用高速剪切反应器生产超细氧化铋工艺探讨

利用硝酸铋溶液和碳酸铵溶液为原料，采用高速剪切反应器，500℃煅烧后可以生产出高纯、超细的氧化铋粉末。该方法制备出的氧化铋平均粒度0．71μm且粒度范围分布窄，颗粒形貌为类球形，晶相为纯α相，指标达到电子压敏陶瓷要求。由于粒度细小，可以在电子压敏陶瓷球磨工艺减少球磨工艺，并具有更好的分散效果。本文对超细的氧化铋粉末形成机理也进行了探讨。     

Deformation Dynamics of a Reactive Medium During Gasless Combustion

Deformation during gasless combustion of 5Ti + 3Si and Ti + C samples was studied experimentally. The dynamics of motion of the material in a gasless combustion wave was studied using highspeed video recording (500 frames/sec) with a spatial resolution of the order of 10 m. It was shown that behind the combustion front, the medium was first expanded and then compressed. The dimensions of the expansion and compression zones were determined.     

锦纶6聚合中冷冻停车工艺的改进

以往锦纶6短丝车间冷冻停车工艺采用自然降温方式,导致停车过程中经常发生设备故障。通过工艺改进,采用自上而下的梯度式降温方式,避免了降温速度不均匀的问题。改进后的工艺克服了原工艺的不足,完全满足了生产技术要求,具有较高的实际应用价值。     

变频器在氯碱生产中的应用

介绍了交流电机变频调速的原理和注意事项,以便合理地使用变频器。     

带速度控制的能量高效的数据收集算法

无线传感网络中, 在保证节点能耗较低, 从而延长网络寿命的基础上, 减小数据收集时延是数据收集的核心问题。为此, 提出了一种带速度控制的能量高效的移动数据收集方法。该方法首先基于节点剩余能量进行动态分簇, 每个簇形成两个簇头来分担簇头能耗; 然后给小车装载双天线, 使得节点能够MIMO数据上传; 最后利用TSP问题找到一条最优路径, 并对移动小车的速度进行控制, 以便小车能够更快地收集数据。仿真实验结果表明, 该方法能够均衡网络流量, 延长网络寿命; 与其他算法相比, 数据收集时延较短。     

基于事件驱动方式的高速串口通信方案的设计

针对串口通信中系统资源利用不足的问题,提出了一种基于多线程技术和事件驱动方式的串口通信方案。该方案在读取串口数据、对串口通信的错误及通信事件进行监视时,用OVERLAPPED结构体中的hEvent参数指定I/O操作完成后所触发的事件对象。然后,用等待函数检查事件对象的当前状态。最后,当事件对象为有信号状态时完成后续操作。在Win7操作系统的Visual C++开发平台下,结合Windows通信API控制串口的编程方法进行仿真测试。测试结果表明该方案能有效解决采用查询方式时因数据高速涌入造成数据丢失的问题。