EFFECT OF SIMULATED WEIGHTLESSNESS ON THE RESPONSE CHARACTERISTICS OF HUMAN BRAIN

In order to systematically investigate the effects of simulated weightlessness on thefunction state of human brain, 15° head-down tilt (HDT) was used to simulate weightless-ness, and the response changes of event-related EEG power spectra, medium-frequencysynchronous potentials and slow-waves were examined in the present study. It was foundthat HDT had characteristic effects on the above EEG responses, suggesting that the ef-fects mainly occurred in the brain's regulatory system, therefore, resulting in changes ofthe brain function state.     

聚合物驱蚊剂的慢释放研究

本文研究了丙烯酸酯共聚物载体对驱蚊剂N,N-二乙基间甲苯酰胺(DETA)慢释放行为的控制,探讨了单体配比、共聚物分子量以及DETA含量对释放速率的影响。结果表明。增加亲水性单体丙烯酸(AA),可提高DETA的释放速率;降低共聚物数均分子量,会减少DETA的释放量;剂型中DETA含量与释放量存在线性正比关系,但DETA的含量增加并不导致释放有效时间的线性增加。本文还就共聚物膜的透湿性和碱溶性作了研究,亲水性单体AA的增加同样导致透湿性和碱溶性的增加。制备的聚合物驱蚊剂经现场应用试验,表明具有良好的长效驱蚊特性。     

Using Unfold‐PCA for batch‐to‐batch start‐up process understanding and steady‐state identification in a sequencing batch reactor

In chemical and biochemical processes, steady‐state models are widely used for process assessment, control and optimisation. In these models, parameter adjustment requires data collected under nearly steady‐state conditions. Several approaches have been developed for steady‐state identification (SSID) in continuous processes, but no attempt has been made to adapt them to the singularities of batch processes. The main aim of this paper is to propose an automated method based on batch‐wise unfolding of the three‐way batch process data followed by a principal component analysis (Unfold‐PCA) in combination with the methodology of Brown and Rhinehart 2 for SSID. A second goal of this paper is to illustrate how by using Unfold‐PCA, process understanding can be gained from the batch‐to‐batch start‐ups and transitions data analysis. The potential of the proposed methodology is illustrated using historical data from a laboratory‐scale sequencing batch reactor (SBR) operated for enhanced biological phosphorus removal (EBPR). The results demonstrate that the proposed approach can be efficiently used to detect when the batches reach the steady‐state condition, to interpret the overall batch‐to‐batch process evolution and also to isolate the causes of changes between batches using contribution plots. Copyright © 2007 John Wiley & Sons, Ltd.     

氮肥管理对夏玉米土壤CH4和N2O排放的影响

通过设置四个不同的氮肥管理措施, 即氮肥施用量300 kg N/ha (N300)和250 kg N/ha (N250)、改进的施肥模式(Optimized)以及施用缓释肥(SRU), 研究华北平原夏玉米生长季土壤与大气之间CH₄和N₂O的交换通量及相应措施的减排潜力. 结果表明, 在2008年整个夏玉米生长季, 土壤都是大气CH₄的净吸收库和N₂O的排放源. 夏玉米生长季土壤氧化吸收的CH₄总量从大到小依次为Optimized > N250 > SRU > N300, 对应的吸收总量依次为624.16、590.07、487.89以及316.02 g CH₄-C/ha, 各处理间氧化吸收的CH₄总量无显著差异. 与N300和N250这两个处理相比, 依据夏玉米对氮肥的需肥规律以及玉米根层土壤速效氮的供给能力而确定氮肥施用量, 同时再平衡施用磷肥和钾肥的改进施肥模式能够显著降低夏玉米生长季N₂O的排放. 施用聚乙烯包膜的尿素也能够显著降低夏玉米季N₂O的排放. 夏玉米生长季土壤排放的N₂O总量从大到小依次为N300 > N250 > Optimized > SRU, 对应的排放总量依次为3462.18、2340.07、1680.00以及911.91 g N2O-N/ha, 相应的N₂O排放系数分别为1.15%、0.94%、0.91%以及0.30%.     

Molecular dynamic study of dielectric polarization and ferroelectricity in a model polar polymer

Molecular dynamics simulations are used to explore the polarization response of a lamellar crystal consisting of folded chains of a highly simplified model polar polymer. The system is based on a united atom model of polyethylene with constrained bond lengths and bond angles, and it is endowed with artificial partial charges placed on the united atoms to give it a simple polar character. Simulations performed with various temperatures, electric field directions, and electric field application histories reveal a complicated sequence of reorientation processes, including pronounced ferroelectric behavior. The sequence includes a weak, temperature‐independent prompt response, and a slow‐rising delay regime with stretched exponential behavior and thermally‐activated reorientation parameters consistent with trans‐gauche (TG) barrier crossings in the amorphous phase. When the delay regime has progressed sufficiently, a primary large‐amplitude response due to organized rotation of large subsegments in the crystalline phase occurs in a rapid manner that requires relatively few TG barrier crossings. A final, extremely slow rise in residual polarization completes the sequence. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015 , 53, 740–759     

微机控制阶梯波慢扫描电路

本文介绍了在相对论电子束起初发射度测量系统中我们研制的微机控制阶梯波慢扫描电路工作原理     

不同US—SSY分子筛为基质的加氢处理催化剂的结构及性能

应用ＸＲＤ、ＸＰＳ、ＥＸＡＦＳ、ＩＲ－ＴＰＤ、ＮＨ３－ＴＰＤ和脉冲微反等多种物理和化学方法，研究了以冷急和自冷方法制备的ＵＳ－ＳＳＹ分子筛，在与γ－Ａｌ２Ｏ３制成混和载体时，两者之间的差异对金属组分在其上的分散和活性组分的形成产生的影响以及给加氢处理催化剂性能带来的变化，为制备高效催化剂提供了科学的依据。     

电介质的结构级别和性质

用组合系综说明了慢效应中的剩余极化．从时域介电谱的慢分量可计算出驻极体中冷冻极化的理论曲线，其结果和实验一致．慢极化属于非马尔可夫过程，其历史记忆效应使电动力学中除麦克斯韦场方程之外还要补充源方程．证明了线性介电响应中存在复介电常数的充分和必要条件为极化过程是马尔可夫过程．在聚合物的β转变中，二级和三级结构运动的恢复力系数出现抛物线型软化．     

Bursting and synchronization transition in the coupled modified ML neurons

Bursting is an important electrical behavior in neuron’s firing. In this paper, based on the fast/slow dynamical bifurcation analysis and the phase plane analysis, two types of bursting are presented in the modified Morris–Lecar neuronal model, and the associated bifurcation mechanisms of switching between the active phase and the silent phase are analyzed. For two coupled bursters, it is found that the same type of coupled bursters may have different synchronization transition path from that of two different types of coupled bursters. The analysis of bursting types and the transition to synchronization may provide us with better insight into neuronal encoding and information transmission.     

Locally one-dimensional difference schemes for the fractional order diffusion equation

Locally-one-dimensional difference schemes for the fractional diffusion equation in multidimensional domains are considered. Stability and convergence of locally one-dimensional schemes for this equation are proved.