Atmospheric icing in a coastal mountainous terrain. Measurements and numerical simulations, a case study

Icing on structures occurs as rime ice, clear ice or wet snow deposit. Reliable forecasts of duration and intensity of this icing require prognoses of standard meteorological parameters, in addition to more specific parameters such as the density (ρ_LWC) of cloud Liquid Water Content (LWC). Icing conditions on the mountain Brosviksåta (723 m a.s.l., 61° 2′ N, 5° 9′ E), on the western coast of Norway were investigated from March 21–24, 2003. A non-rotating vertical steel rod mounted on a scale was used to measure the accumulated ice load. Air temperature, relative humidity and wind were measured at three levels along the mountain slope. The maximum build-up of ice, in this case study, was measured to 4.5 kg on a 1 m high 0.14 m diameter rod. Comparison of measured ice-growth rate and calculated ρ_LWC gave a correlation coefficient of 0.85.A mesoscale atmospheric model (MM5) has also been tested at a high horizontal resolution (1 km) in order to evaluate its ability to reproduce weather conditions where freezing occurs. Comparison from the direct measurements and calculations, with results from MM5, gave 58% of the measured accumulated ice growth. Further studies of real-time cases on a real-time system at a coarser model resolution will reveal its capability for forecasting freezing events.     

USS及S7-300在恒压供水中的应用

本文着重介绍了USS在实际中的应用，以及如何解决PJD调节中随动性与稳定性的矛盾。     

在MM5中实现IKAWA参数自适应选择

在"大规模科学计算在生态环境研究中的应用"项目的研究中,我们移植国际上比较成熟的软件MM5进行气象数据场的计算.在实际计算时,由于初始数据采集误差较大等原因,MM5中采用了很多固定的平滑因子,造成MM5不能模拟复杂多变环境现象,而我国地形、环境的多样性,使得数值计算结果不能令人满意.为了解决这个问题,我们引入自适应算法对软件中IKAWA参数进行自适应选择.由于是并行计算,改进引起的额外时间开销是可接受的.最后给出算例分析改进的有效性.     

基于网格运算实现MM5模式中Web Service

论文介绍了基于网格运算实现MM5模式的实验环境和实现的方法,实验结果具有一定的实用价值。     

基于LIN总线的汽车后视镜控制模块设计

以MC9S12DG128为主控单元、MM908E622为后视镜单元,采用单主多从的总线控制方式,设计了一种基于LIN总线的汽车后视镜控制模块。主控单元以单片机MC9S12DG128为核心,通过LIN收发器MC33661实现对总线数据的收发,同时将液晶触摸信号转换为LIN指令以达到对后视镜单元的整体控制。后视镜单元以MM908E622作为从单元控制器,内置LIN收发器和电机驱动电路,具有优异的调控能力,适用于控制汽车高端后视镜。设计中体现了汽车车身电子的智能化和网络化,在汽车工业中有较高的应用价值。     

Flexible Expectile Regression in Reproducing Kernel Hilbert Spaces

Expectile, first introduced by Newey and Powell in 1987 Newey, W. K., and Powell, J. L. (1987), “Asymmetric Least Squares Estimation and Testing,” Econometrica, 55, 819–847.[Crossref], [Web of Science ®] , [Google Scholar] in the econometrics literature, has recently become increasingly popular in risk management and capital allocation for financial institutions due to its desirable properties such as coherence and elicitability. The current standard tool for expectile regression analysis is the multiple linear expectile regression proposed by Newey and Powell in 1987 Newey, W. K., and Powell, J. L. (1987), “Asymmetric Least Squares Estimation and Testing,” Econometrica, 55, 819–847.[Crossref], [Web of Science ®] , [Google Scholar]. The growing applications of expectile regression motivate us to develop a much more flexible nonparametric multiple expectile regression in a reproducing kernel Hilbert space. The resulting estimator is called KERE, which has multiple advantages over the classical multiple linear expectile regression by incorporating nonlinearity, nonadditivity, and complex interactions in the final estimator. The kernel learning theory of KERE is established. We develop an efficient algorithm inspired by majorization-minimization principle for solving the entire solution path of KERE. It is shown that the algorithm converges at least at a linear rate. Extensive simulations are conducted to show the very competitive finite sample performance of KERE. We further demonstrate the application of KERE by using personal computer price data. Supplementary materials for this article are available online.     

Identification of a potential proton donor to the linking oxygen atom in a three-metal ion assisted catalysis pathway catalyzed by Fructose-1, 6-bisphosphatase

In this paper, the dephosphorylation mechanism of FBP to F6P catalyzed by the Fructose-1, 6-bisphosphatase (St-Fbp) from Sulfolobus tokodaii was studied using quantum mechanical/molecular mechanical (QM/MM) approach. Based on the experimental results, total five possible catalytic mechanisms (path1-path4′) were designed. The most possible dephosphorylation reaction follows a two-step mechanism (path2): a dephosphorylation process (with D12 being an base of W6 and residue K133 being the proton donor of the linking FBP:O4) and a proton exchange process (between K133 and the water W1). Furthermore, the three-step of path4 is also possible: a dephosphorylation process (with D54 being the base of W6 and residue K133 being the proton donor of the linking FBP:O4) and two proton exchange processes (first between residues D54 and D12 then between K133 and the water W1). The relative low energy of this pathway suggests that D54 might also be a base except D12. Our calculations indicate that K133 is the preferred proton donor during the breaking of the phosphate bond O4-P1, with the W1 being an alternative proton donor to access to a more stable product. Findings here give a new insight into the understanding of catalytic mechanism of FBPase.     

Binding mode analysis,dynamic simulation and binding free energy calculations of the MurF ligase from Acinetobacter baumannii

MurF ligase catalyzes the final cytoplasmic step of bacterial peptidoglycan biosynthesis and, as such, is a validated target for therapeutic intervention. Herein, we performed molecular docking to identify putative inhibitors of Acinetobacter baumannii MurF (AbMurF). Based on comparative docking analysis, compound 114 (ethyl pyridine substituted 3-cyanothiophene) was predicted to potentially be the most active ligand. Computational pharmacokinetic characterization of drug-likeness of the compound showed it to fulfil all the parameters of Muegge and the MDDR rule. A molecular dynamic simulation of 114 indicated the complex to be stable on the basis of an average root mean square deviation (RMSD) value of 2.09 Å for the ligand. The stability of the complex was further supported by root mean square fluctuation (RMSF), beta factor and radius of gyration values. Analyzing the complex using radial distribution function (RDF) and a novel analytical tool termed the axial frequency distribution (AFD) illustrated that after simulation the ligand is positioned in close vicinity of the protein active site where Thr42 and Asp43 participate in hydrogen bonding and stabilization of the complex. Binding free energy calculations based on the Poisson-Boltzmann or Generalized–Born Surface Area Continuum Solvation (MM(PB/GB)SA) method indicated the van der Waals contribution to the overall binding energy of the complex to be dominant along with electrostatic contributions involving the hot spot amino acids from the protein active site. The present results indicate that the screened compound 114 may act as a parent structure for designing potent derivatives against AbMurF in specific and MurF of other bacterial pathogens in general.     

Molecular insights into inclusion complexes of mansonone E and H enantiomers with various β-cyclodextrins

The structural dynamics and stability of inclusion complexes of mansonone E (ME) and H (MH) including their stereoisomers with various βCDs (methylated- and hydroxypropylated-βCDs) were investigated by classical molecular dynamics (MD) simulations and binding free energy calculations. The simulation results revealed that mansonones are able to form inclusion complexes with βCDs. The guest molecules are not completely inserted into the host cavity, their preferably positions are nearby the secondary rim with the oxane ring dipping into the hydrophobic inner cavity. The encapsulation process leads to a higher rigidity of the βCDs enhancing the intramolecular hydrogen bond formation ability and decreasing the chance of glucopyranose rotation. According to the MM-PBSA binding free energy calculation, all considered inclusion complexes are stable and the binding energies are mainly caused by van der Waals interactions. Moreover, the free energy calculations showed significant differences in the complexation energies for the stereoisomers, which could enable the separation of the isomers by analytical techniques for further pharmaceutical applications.     

带反射腔开式套筒天线方向图计算

采用电磁场数值域中的矩量法对带反射腔开式套筒天线进行分析，并通过计算机编制程序计算出了该天线的方向图以及半功率波瓣宽度，结果与有单位提供的实测基本吻合。