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A new structure of short training sequence for symbol synchronization in OFDM-PON system is proposed in this paper. By adjusting the subcarrier allocation scheme of short training sequence in a wireless LAN, it makes the mean of short training sequence signal in time domain from non-zero to zero mean and solves the receiving data demodulation interference caused by the wrong trail of the non-zero mean short training sequence in time-domain. Data demodulation simulation and experimental results show that the improved method can effectively reduce the training sequence interference errors caused by tailing.

The optically pure ethyl nipecotate is an important drug intermediates. It was used for a variety of synthesis of APIs and pharmaceutical intermediates. In this paper we launched a study of the split of ethyl nipecotate. An efficient resolution of (±)-nipecotic acid has been achieved by the fractional crystallization with good yield and high enatio. The compound (S)-ethyl-1-(2-thiopheneacetyl)-3-piperidine-carboxylate is an investigational immune potentiating agent targeting direct stimulation of immune cells, useful for the prevention of infectious diseases in livestock.

Calcium ions, magnesium ions, and silicate were the main reasons for the high silting density index (SDI) of natural waters. Therefore, they posed serious membrane fouling problems in the nanofiltration (NF) system, which restricted the wide application of this excellent drinking water treatment technology. In this study, the sand filtration and the micro-flocculation/sand filtration hybrid process were investigated as the pretreatment process of NF for SDI reduction. Compared with the sand filtration, the hybrid process of micro-flocculation/sand filtration was more effective for SDI reduction. When polyaluminium chloride (PAC) was used as the flocculant at a dose of 10 mg/L and the filtration rate of the sand filter was controlled at 10 m/h, the SDI value in the effluent of the pretreatment process maintained below 3. As a result, the subsequent NF system stably ran for one year. 68% CODMn was removal by NF. The membrane fouling during the operation was quite slight as the transmembrane pressure (TMP) increased by 17% after one-year use. Chemical cleaning with sodium tripolyphosphate (2%) and sodium dodecyl benzene sulfonate (0.25%) at 6 months interval could effectively recover the flux loss of the NF membrane.

An effective resolving agent, (D)-dibenzoyl tartaric acid (2b), was screened to yield direct resolution of (S)- ethyl nipecotate (1) with high optical purity and yield. Molecular recognition was studied by 1H NMR, IR, DSC and single crystal diffraction of the pair of diastereomeric salts. The less-soluble salt formed a supra molecular structure by enantio differentiating self-assembly.

The rheological behavior of PA1010/POE/OMMT nanocomposites was studied by using XLY-Ⅱ rheometer. The curves of lgτω～lgγ’ω, lgηa～lgγ’ω, lgηa～1/T were obtained. The experimental results showed that PA1010/POE/OMMT nanocomposites were pseudoplastic fluid. The apparent viscosity of the blends reduced with the increase of the shearing stress．Compared with PA1010/POE blends, the addition of OMMT increased the apparent viscosity. The viscous activation energy of PA1010/POE/OMMT blends declined as the increase of shearing stress, which indicated that the PA1010/POE/OMMT blends could be processed over a wide temperature at a high shearing stress.

A synthetic approach to synthesize 3,4-ethylenedioxyfuran from a common precursor Diglycolic acid is reported. Starting from ethylene diglycol, a six-step synthesis afforded EDOF in 10% overall yield. The procedure described herein offers several advantages, including high product yields, easy purification.

Heterocyclic electron-poor monomer [1,2,5]thiadiazolo[3,4-c]pyridine have been synthesized in high yields over five steps from readily available starting materials. The new deficient acceptor has good solubility in organic solvents so as to permit an appropriate coating process.

Heterocyclic monomers based on 2,1,3-benzothiadiazole bearing solubilizing side chains have been synthesized in high yields over four steps from readily available starting materials. A multistep synthesis of the electron-poor 6, 7-dihydro-1, 4-dioxino-[2, 3-f][2,1,3]-benzothiadiazole are presented. The new dificient acceptor has good solubility in organic aolvents to permit an appropriate coating process.

Watermarking technique has widely developed prospects in information protection, digital right authentication and electronic commerce. This paper describes the basic concept, character, classify of watermarking technique. The function of watermarking technique in digital information security and protection is analyzed in detail.

A mide, simple and efficient synthetic procedure for the preparation of 2,7-dibromo-2′,3′,6′,7′-tetra(2-methylbutyloxy)spirobifluorene and key intermediates, tetra(2-methlbutyloxy)biphenyl ，2-bromo-4,5,3′,4′-tetra(2-methylbutyloxy)biphenyl, 2,7-Dibromo-2′,6,3′,7′--tetra(2-methylbutyloxy)biphenyl-9-Fluorenol, has been developed. The procedure described herein offers several advantages, including high product yields, easy purification, and large scale production. Ether protected 2,7-dibromo-9,9′-spirobifluorene has good solubility in organic aolvents to permit an appropriate coating process, ability to achieve various colors so as to make full color display elements possible.

nylon 11 nanocomposites with different montmorillonite loadings were successfully prepared by melt compounding. XRD and TEM show the exfoliated nanocomposites are formed at low montmorillonite concentration(less than 2wt%) and the intercalated nanocomposites are obtained at higher montmorillonite contents. TGA shows that the thermal stability of the nanocomposites is improved by 27°C when the montmorillonite content is only 2wt%. Mechanical testing shows that the Izod impact strength of all nanocomposites are higher than that of the neat nylon 11, but the tensile strength of the nanocomposites decrease at low nanofiller concentrations (less than 8wt%) and than increased, when the montmorillonite content is 10wt% ,the tensile strength of the nanocomposite is 5% improved than neat nylon 11. This is may be due to the strong interaction between the nylon 11 matrix and the montmorillonite interface.