Abstract: Efficient Z-transform implementa-tion of the complex frequency-shifted perfectly matched layer (CFS-PML) based on the stretched coordinate PML (SC-PML) formulations and the D-B formulations is proposed for truncating meta-material finite-difference time-domain (FDTD) lattices. In the proposed PML formulations, the Z-transform method is incorporated into the CFS-PML FDTD implementation. The main advantage of the proposed formulations can allow direct FDTD implementation of the Maxwell’s equations in the PML regions. A numerical test has been carried out in a three dimensions (3-D) FDTD domain to validate the proposed formulations. It is shown that the proposed formulations with CFS scheme are efficient in holding good absorbing performances.
Abstract: A double-mesa hetero-junction bipolar structure of NPN type microwave power device is used. The Si is chosen for emitter and collector, and Si1-xGex alloy is for base. Based on some experiment data, a numerical method is used to get an equation about forbidden band Eg via the variety composition of Ge at 300K using MATLAB, which is more precise than linearization. We also calculate the collector current density JC via the variety of VBE and the obtained equation is consistent with the experiment result. An optimum Ge composition value was found. It has practical significance for the device design and simulation.
Abstract: In this paper, activated carbon fibers were modified by different chemical reagents. The modified adsorbents were used to investigate adsorption and separation performance of CO2/CH4 gases mixture, and then it could get the best modified adsorbent. The experimental results show that amine can't great grafting on activated carbon fiber. Compared with blank activated carbon fibers, the adsorption property of CO2 did not have much influence on the activated carbon fiber modified by amine. However, it can increase the nitrogen functional groups and the specific surface area on the surface of activated carbon fiber that were modified with nitric acid and ammonia. The above two points were conductive to the adsorption and separation of CO2/CH4 mixture gases.
Abstract: The pipe heat transfer models were constructed, respectively, to simulate the cryogenic insulated structure, nonlinear partial differential equations was obtained considering the temperature-dependent variation in thermal conductivity of insulation materials. In order to get the temperature profile of insulation layer, Kirchhoff integral method was introduced to process, program, and iteratively calculate the simplified energy equations. The influence of heat-transfer process related to the thermal conductivities of four cold insulators was analyzed. Results indicate that phenolic foam, hydrophobic perlite, and RPUR have superior low-temperature insulation at cryogenic environment, while foam glass has better low-temperature insulation at normal temperature. The thickness of inner cryogenic-insulation layer can be reduced largely by using a multicomponent cold insulator in the discharge pipe of LNG stations, which can save both materials and costs. Meanwhile, it offers a new method to solve variable thermal conductivities.
Abstract: As the unique properties of semiconductor material, it is made of many semiconductor Hall devices. Semiconductor Hall device has the advantages of simple structure, small volume, long service life, sensitive to magnetic field induction, strong frequency response and large variable voltage output. Hall Effect of semiconductor material is one kind of electromagnetic effects, which has practical significance. It is widely used in measurement technology, electronic technology, automation technology and so on.
Abstract: In order to gain insight into the specific function of the cassava cell wall invertase 6 (MeCWINV6), the promoter sequence of MeCWINV6 gene was cloned using the PCR amplification approach. 118 bp CDS sequence and 1042 bp potential promoter sequence of MeCWINV6 gene were obtained. PlantCARE analyzed the putative cis-elements in silico revealed that these elements can be grouped into five classes: basic transcription elements (CAAT box and TATA box), light responsive elements (ACE, AE-box, ATCT-motif, AT1-motif, Box 4, GAG-motif, GT1-motif and Sp1), phytohormone responsive motifs (GARE-motif, TATC-box, TGACG-motif and TCA-element), defense and stress responsive element (TC-rich repeats and HSE), wounding and pathogen responsive elements (W-box and WUN-motif). This data demonstrate that it might be associated to regulate the cell wall invertase gene function in source-sink relations of cassava starch accumulation and response to internal and environmental stimuli.
Abstract: Since the composition of crude bio-oil was complex, model compounds were usually used in the study of cracking to simulate the actual bio-oil. However, the cracking of pure model compound mixture generated an inferior oil phase which had a high content of oxygenated byproducts. When ethanol was adopted as the co-reactant, the reactant conversion, yield and quality of oil phase were obviously improved. The conversions of the reactants were 100% and the selectivity of the oil phase was 31.5wt% when the concentration of model compound mixture in the feed reached 30%. Meanwhile, the oil phase also had a superior quality which was entirely composed of aliphatic and aromatic hydrocarbons.
Abstract: A new composite electrolyte for lithium-ion batteries (LIBS) was prepared by combining N-methyl-N-propylpyrrolidinium bis (trifluoromethanesulfonyl) imide (PYR13TFSI), N-methyl-N-pr-opylpiperidinium bis (trifluoromethanesulfonyl) imide (PP13TFSI) and lithium difluoro (oxalate) bor-ate (LiDFOB). Graphite electrode was tested in the LiDFOB-containing electrolyte, exhibiting higher reversible charge/discharge capacity and better cyclic stability. An initial charge capacity of 351.5 mAh⋅g-1 is obtained and a stable capacity of above 332.8 mAh⋅g-1 is retained after 30 cycles. The coulombic efficiency remains high above 99.3%. The outstanding cell performance was associ-ated with the formation of stable solid electrolyte interface (SEI) film on the surface of electrodes derived from LiDFOB.
Abstract: Systematic research on monomolecular layer of symmetrically substituted copper (II) phthalocyanine (CuPc) derivatives bas been done. An attention is focused upon final determination of the transfer pressure in an ordered nanoassembly film of CuPc by comparing different methods about surface pressure-area (-A) isotherm, morphology observation and thickness measurement by transmission electron microscopy (TEM) . The present study and improvement methods provide new insight into the choice of transfer pressure for mono molecule layer .