Measurements and correlation of effect of cosolvents on the solubilities of complex molecules in supercritical carbon dioxide

A new transparent microscale circulation-type high pressure equilibrium cell with on-line sampling was devised. With this apparatus, experimental solubility of molecularly complex species such as steroids (cholesterol, stigmasterol and ergosterol) and fatty acids (palmitic acid and stearic acid) in supercritical carbon dioxide(sc-C0₂) were measured. Also, to find an appropriate substance for enhancing both the polarity and the solubility power of the SC-CO₂ solvent, we arbitrarily selected three polar substances such as acetone, methanol and water and the effect of these cosolvents on the solubility of solutes in SC-CO₂ are examined. The supercritical phase equilibrium data of solute-cosolvent-sc-CO₂ systems were quantitatively correlated using a new equation of state based on the lattice fluid theory incorporated with the concept of multibody interaction. We found that the addition of tracer amount of acetone or methanol to SC-CO₂ enhances the solubility of all solutes about thirty to sixty times when compared with the case of pure sc-CO₂ However, for the case of cosolvent water, no further enhancement of the solubility of solutes was realized. Also, the versatile fittability of the equation of state proposed in this work was demonstrated with the newly measured ternary supercritical equilibrium data.     

Suppressive effect of corticosteroids on the gene expression of interleukin-5 and eosinophil activation in asthmatics

Although cortico steroids are effective anti-inflammatory agents in ameliorating asthma symptoms and bronchial hperreactivity, their mechanism of action is unknown. Interleukin (IL)-5 is known to play a key role in regulating eosinophil proliferation and activation. Therefore, we examined the changes of IL-5 mRNA expressions in PBMC semi-quantitatively with RT-PCR as well as serum ECP levels and MCH-PC20 values in asthmatics before and after being treated with corticosteroids. The results revealed that there were significant decrease in the level of IL-5 mRNA and serum ECP concentration after therapy (P < 0.05) and there was remarkable improvement in the values of MCH-PC20 and FEV1% (P < 0.05). It was also found that the changes of serum ECP levels or MCH-PC20 values were accompanied by a reduction in IL-5 mRNA expression (r = 0.5426 or 0.4857, P < 0.05). These results suggested that the therapeutic effects of corticosteroids in asthma may result from modulation of IL-5 gene expression with consequent inhibition of eosinophil activation.     

威海市污水处理深海排放工程的设计

威海市污水处理深海排放工程是为改善其水域环境而建设的一英包括市区排水系统，污水预处理厂，输水管道和海洋放流管系统在内的完整而典型的工程，因此其工程设计扣的经验将会对同类项目的设计与工程建设有所借鉴。     

Selection of network and learning parameters for an adaptive neural robotic control scheme

This paper presents the results of a study in the design of a neural network based adaptive robotic control scheme. The neural network used here is a two hidden layer feedforward network and the learning scheme is the well-known backpropagation algorithm. The neural network essentially provides the inverse of the plant and acts in conjunction with a standard PD controller in the feedback loop. The objective of the controller is to accurately control the end position of a single link manipulator in the presence of large payload variations, variations in the link length and also variations in the damping constant. Based on results of this study, guidelines are presented in selecting the number of neurons in the hidden layers and also the parameters for the learning scheme used for training the network. Results also indicate that increasing the number of neurons in the hidden layer will improve the convergence speed of learning scheme up to a certain limit beyond which the addition of neurons will cause oscillations and instability. Guidelines for selecting the proper learning rate, momentum and fast backpropagation constant that ensure stability and convergence are presented. Also, a relationship between the r.m.s. error and the number of iterations used in training the neural network is established.     

A new hybrid active power filter (APF) topology

In this paper, a new hybrid active power filter topology is presented. A higher-voltage, low-switching frequency insulated gate bipolar transistor (IGBT) inverter and a lower-voltage high-switching frequency metal oxide semiconductor field effect transistor (MOSFET) inverter are used in combination to achieve harmonic current compensation. The function of the IGBT inverter is to support utility fundamental voltage and to compensate for the fundamental reactive power. The MOSFET inverter fulfills the function of harmonic current compensation. To further reduce cost and to simplify control, the IGBT and MOSFET inverters share the same DC-link via a split capacitor bank. With this approach harmonics can be cancelled over a wide frequency range. Compared to the conventional APF topology, the proposed approach employs lower dc-link voltage and generates less noise. Simulation and experimental results show that the proposed active power filter topology is capable of compensating for the load harmonics     

Motivations for the San Fernando Valley Secession Movement: The Political Dynamics of Secession

I argue that the motivation for the San Fernando Valley secession movement can be explained as a desire for local control based on democratic ideals, but I emphasize that the movement is also motivated in part by the tangible benefits that accompany such autonomy. After a brief look at possible economic and racial motivations behind the secession movement, I look for a political divide between the city and the Valley, based on literature that has found political divisions between urban and suburban areas. Evidence of a political divide is mixed, but does indicate that the Valley lacks representation in comparison to the rest of the city. Valley residents may also fear increasing minority political power, which could erode the dominance of Valley whites at the polls. There is also evidence that those who favor secession are most dissatisfied with representation and most concerned with getting their fair share of services from the city, indicating a strong desire for more local control. Images of a smaller, more democratic government, and a more engaged local civic community are prime motivations in the Valley’s quest for autonomy, though the possibility of reduced taxes, land use control, and increased political power do offer secessionists clear substantive benefits in addition to more democratic goals.     

Chemical leaching and magnetic properties of non-equilibrium Al(Co–Cu) powders produced by rod milling

We report upon the chemical leaching and magnetic properties of nanoscale crystalline Al_0.6(Co₂₅Cu₇₅)_0.4 alloy powders produced by rod milling. X-Ray diffractometry (XRD), transmission electron microscopy, differential scanning calorimetry, vibrating sample magnetometry, and superconducting quantum interference device magnetometry were used to characterize the as-milled and leached specimens. After 400 h of milling, only the b.c.c. phase of the intermetallic compound γ-Al_3.892Cu_6.10808 was detected by XRD. After annealing the leached specimen at 600 °C for 1 h, the nanoscale crystalline phase was transformed into the f.c.c. Cu phase, and this was accompanied by a change in the magnetic properties. The peaks of the magnetization shifted towards lower temperature with increasing external field. The temperature behavior at T_f (45 K) for direct current (d.c.) magnetic susceptibility measurements was quite different for field cooling and zero-field cooling. After cooling the leached specimen from 800 °C, magnetization increased gradually.     

Theory and design of a tapered line distributed photodetector

We present the theory and design of a tapered line distributed photodetector (TLDP). In the previously demonstrated velocity-matched distributed photodetector (VMDP), high electrical bandwidth is achieved by proper termination in the input end to absorb reverse traveling waves, sacrificing one-half of the quantum efficiency. By utilizing the tapered line structure and phase matching between optical waves and microwaves in our analyzed structure, a traveling-wave photodetector is more realizable and ultrahigh bandwidth can be attained due to removal of the extra input dummy load that sacrifices one-half of the total quantum efficiency. To investigate the advantages of TLDP over VMDP, we calculate their electrical bandwidth performances by using an analytic photodistributed current model. We adopted low-temperature-grown (LTG) GaAs-based metal-semiconductor-metal (MSM) traveling-wave photodetectors as example unit active devices in the analytic bandwidth calculation for their high-speed and high-power performances. Both VMDP and TLDP in our simulation are assumed to be transferred onto glass substrates, which would achieve high microwave velocity/impedance and make radiation loss negligible. The simulated bandwidth of a properly designed LTG GaAs MSM TLDP is /spl sim/325 GHz, which is higher than the simulated bandwidth of the LTG GaAs MSM VMDP with an open-circuit input end (/spl sim/240 GHz) and is almost comparable to the simulated bandwidth of an input-terminated LTG GaAs MSM VMDP (/spl sim/330 GHz). This proposed method can be applied to the design of high-bandwidth distributed photodetectors for radio-frequency photonic systems and optoelectronic generation of high-power microwaves and millimeter waves.     

吐丝圈径对大规格高碳盘条组织性能的影响

计算与分析了斯太尔摩冷线上盘条的吐丝圈径、搭接密度及"佳灵"装置横向布风曲线之间的关系,研究了吐丝圈径的大小对大规格82B盘条组织和性能的影响,确定了大规格82B盘条最小吐丝圈径应为980mm.