Relationships among the signal coherence-time of matched-field processing （MFP）, the acoustic frequency, the source-receiver range, and the sound speed standard deviation （STD） caused by internal waves in shallow water, are numerically investigated based on oceanographic data from two shallow water experiments. It is found that the coherence-time can be fitted with an inverse square-root power of range, a near inverse 1 power of frequency, and inverse 1.3 power of sound speed STD.
Two polythiophene derivatives using fluorine atoms and hexyl or hexyloxy group as electron-withdrawing and donating substituents have been synthesized. The introduction of fluorine atoms to the polythiophene backbones simultaneously lowers the HOMO and narrows the bandgap, and the stronger electron-donating ability of hexyloxy side chain further reduces the bandgap. As a result, poly[3-hexylthiophene-2,5-diyl-alt-3,4-difluorothiophene] （PHTDFT） shows HOMO and bandgap of -5.31/1.83 eV and poly[3,4-dihexyloxythiophene-2,5-diyl-alt-3,4-di- fluorothiophene] （PDHOTDFT） shows HOMO and bandgap of -5.14/1.68 eV, both are lower than --4.76/2.02 eV of P3HT. Benefiting from the lower HOMO, PHTDFT：PC61BM （1 ＂ 1） polymer solar cells obtain a power conversion efficiency of 1.11% and an impressed open-circuit voltage of 0.79 V under solar illumination AM1.5 （100 mW/cm2）.
Linquan HuangDong YangQiang GaoYan LiuShengmei LuJian ZhangCan Li
Responses of caryopsis germination, seedling emergence, and development of Agropyron cristatum （L.） Gaertn. （Gramineae） and Bromus inermis Leyss. （Gramineae）, two dominant perennial grasses in the Otindag Sandland of China, to different sand water content （SWC; 1%, 2%, 3%, 4%, 6%, 8%, 12%, 16%, and 20%） were studied comparatively. The results showed that the germination responses of the two grasses to SWC were similar （i.e. caryopses could not germinate when the SWC was below 3%; at SWC ranging from 3% to 12%, the higher the SWC, the higher the germination percentage; and at a SWC of 12%-20%, germination reached similarly high percentages）. At a sand burial depth of 0.5 cm, the threshold of SWC for seedling emergence was 6% forA. cristatum and 8% forB. inermis; at 12%-20% SWC, the seedling emergence of both species reached similarly high percentages. The seedling growth responses of these two species to SWC gradients were different. For A. cristatum, the biomass of seedlings increased with SWC from 6% to 12%, and decreased with SWC from 12% to 20%. For B. inermis, the biomass of seedlings always increased with SWC from 8% to 20%. The results also showed that the seedlings of both species allocated more biomass to the roots with decreases in SWC. The SWC changes from April to October in natural microhabitats of both species suggested that the SWC may play an important role in caryopsis germination, seedling emergence, and the growth characteristics of the two grasses. The responses of caryopsis germination, seedling emergence, and the growth characteristics of these two species to SWC may determine their distribution pattems in the Otindag Sandland.
Hui-Ling YANGXuan-Wei ZHUMing DONGZhen-Ying HUANGZhi-Ping CAO
Transformation optics offers remarkable control over electromagnetic fields and has recently opened an exciting gateway to design ＇field rotator devices＇. We propose a distributed field rotator with open windows based on composite transformation optics, which consists of a central circular region and several isolated components. The number, position and size of the components can be controlled freely by the design purpose. Full-wave simulations are performed to demonstrate its function, which is equivalent to a classic field rotator. However, such a distributed rotator makes it much easier to access and make use of the rotated field in the central region, compared to the closed classic field rotator, especially in the case of 3D situations.
We have further investigated Turing patterns in a reaction-diffusion system by theoretical analysis and numerical simulations. Simple Turing patterns and complex superlattice structures are observed. We find that the shape and type of Turing patterns depend on dynamical parameters and external periodic forcing, and is independent of effective diffusivity rate σ in the Lengyel Epstein model Our numerical results provide additional insight into understanding the mechanism of development of Turing patterns and predicting new pattern formations.
WU Yan-Ning WANG Ping-Jian HOU Chun-Ju LIU Chang-Song ZHU Zhen-Gang
The Jovian magnetosphere is modulated by the solar wind and centrifugal force. The configuration of the magnetic field in the previous model of the magnetosphere including the centrifugal force is consistent with the observations at low magnetic latitude （Λ〈50°）, while there is a substantial difference between the results of the model and the observations at high magnetic latitude （Λ≥50°）, especially in the distant magnetotail. Based on the previous model, a new configuration of the Jovian magnetosphere in the night side is suggested by a three-step transformation in this study. The new magnetosphere obtained by the transformation method is flattened in the z-direction and stretched in the x-direction in distant magnetotail, which agree with general knowledge.
Composite materials with interpenetrating network structures usually exhibit unexpected merit due to the cooperative interaction. Locally resonant phononic crystals （LRPC） exhibit excellent sound attenuation performance based on a periodical arrangement of sound wave scatters. Inspired by the interpenetrating network structure and the LRPC concept, we develop a locally network anechoic coating （LNAC） that can achieve a wide band of underwater strong acoustic absorption. The experimental results show that the LNAC possesses an excellent underwater acoustic absorbing capacity in a wide frequency range. Moreover, in order to investigate the impact of the interpenetrating network structure, we fabricate a faultage structure sample and the network is disconnected by hard polyurethane （PU）. The experimental comparison between the LNAC and the fanltage structure sample shows that the interpenetrating network structure of the LNAC plays an important role in achieving a wide band strong acoustic absorption.
By crossing bread wheat cultlvar GC8901 with the 1D monosonlc line of Xiaoyan No. 6 and backcrosslng the offsprlng with the Xlaoyan No. 6 1D monosonlc llne for 5 years, high-molecular-welght glutenin subunlts 1Dx5＋1Dy10 from GC8901 have been transferred Into wheat cultivar Xiaoyan No. 6. The BC5F1 offspring lines had been detected by using methods of cytology, marker, molecular marker and six elite single plants with high molecular-welght glutenin subunlts： lAx1, 1Bx14＋1 By15, 1Dx5＋1 Dy10 were Identified. Those lines have high-yleld potential with better agronomic characters and have been used In high quality wheat breeding processes as well.
