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With the goal of achieving high stability and reliability to support underwater point-to-point communications and code division multiple access (CDMA) based underwater networks, a direct sequence spread spectrum based underwater acoustic communication system using dual spread spectrum code is proposed. To solve the contradictions between the information data rate and the accuracy of Doppler estimation, channel estimation, and frame synchronization, a data frame structure based on dual spread spectrum code is designed. A long spread spectrum code is used as the training sequence, which can be used for data frame detection and synchronization, Doppler estimation, and channel estimation. A short spread spectrum code is used to modulate the effective information data. A delay cross-correlation algorithm is used for Doppler estimation, and a correlation algorithm is used for channel estimation. For underwater networking, each user is assigned a different pair of spread spectrum codes. Simulation results show that the system has a good anti-multipath, anti-interference, and anti-Doppler performance, the bit error rate can be smaller than 10−6 when the signal-to-noise ratio is larger than −10 dB, the data rate can be as high as 355 bits/s, and the system can be used in the downlink of CDMA based networks.

Tire pyrolysis char (TPC) was used as a carrier to prepare Ni/TPC catalyst by homogeneous precipitation method. The characteristic of synthetic catalyst was determined by EDX, SEM, XRD, TG and BET. Meanwhile, the performance of Ni/TPC catalyst including reforming temperature, holding time, nickel loading and usage time on the straw pyrolysis gas reforming was investigated in a tube furnace. The results showed that TPC was rich in char and metal. Ni was well loaded on TPC which had a good thermal stability with a specific surface area of 62 m2/g. The Ni/TPC catalyst could obviously improve the burning gas content. The highest catalytic efficiency was obtained at reforming temperature of 750°C and 10 min holding time with 30% Ni loading. The content of H2 in the gas was high and relatively increased by 50% after using the catalyst for 850 min. The Ni3ZnC0.7 active component structure converted to FeNi3 after long-term used with high and stable catalytic activity. TPC had the ability to be a new type of carrier for nickel catalyst.

Waste sediment generated during tunnel construction is applied to prepare synchronous grouting material, where the influences of fly ash, slag powder, and bentonite on the rheological properties (such as consistency, fluidity, setting time, drainage rate, and stone rate) are studied. The results show that adding fly ash content increases the initial consistency, setting time, and fluidity of grouting material, but also increases its drainage rate and decreases its stone rate. The addition of slag powder results in a slight increase in the setting time and fluidity of the grouting material, yet a decrease in the initial consistency value. In contrast, with the addition of bentonite, both the initial consistency and fluidity of the grouting material decrease. Finally, the optimal mix ratio of high-performance and low-cost grouting materials is fixed to be 30% fly ash, 50% slag powder, and 10% bentonite. Therefore, the fluidity of grouting material can be 170 mm, with an initial consistency of 122 mm, setting time of 1050 min, stone rate of 96.2%, drainage rate of 1.5%, and 28-day compressive strength of 8.3 MPa.

High dropping non vibration concrete is widely used in high-rise steel tube concrete construction. In this paper, a high dropping non vibration self-compacting concrete with high mobility, low slump loss, and good anti-segregation ability is developed by mixing addition of PCA superplasticizer and SCC composite expansive admixture. The test results showed that the admixture and cement used in the test possess sound compatibility. The slump flow of self-compacting concrete prepared are more than 660mm, T500 of 2.8~7.5s, 1h slump flow loss of less than 10%, and the segregation rate of less than 7.5%. Through strictly control production and dropping construction, supplemented by field ultrasonic detection measures, the high dropping self-compacting concrete in steel tube achieved successful application for a high-rise building.

On the basis of experimental research about PVA fiber concrete, combined with the technology measures such as expansive belt, construction quality monitoring, the jointless design and construction is successfully carried out for an industry tank. The water storage test results showed that impervious performances can meet the requirements of specification and achieved desired effects.

Effect and benefits of a product or service could be analyzed and evaluated by life cycle assessment during the whole life cycle. Urban sewage treatment plants could improve and control urban water pollution escalating, but it also had certain harm to environment. Effect and benefits of urban wastewater treatment plant A and B were analyzed and evaluated, 13 factors were selected, and comprehensive benefits were researched quantificationally using the method of analytic hierarchy process. It found that urban wastewater treatment plant A who applied A/O process had better benefits than urban wastewater treatment plant B who applied BIOLAK process.

Two unsymmetrical complexes, [NiL1]ClO4 (1) and [NiL2]ClO4 (2) have been synthesized and characterized by IR, UV, ES-MS and single crystal X-ray diffraction, where HL1 and HL2 are, respectively, the [1+1] condensation products of 2,6-diformyl-4-X-phenol (X = F or CH3) with N 1-(2-aminoethyl)-N 2-(4-nitrobenzyl) ethane-1,2-diamine. The coordination geometry of the metal in both complexes can be approximately described as square planar with a mean plane deviation of 0.032 A in complex 1 and 0.027 A in complex 2, respectively. The binding activities of the complexes toward calf-thymus DNA have been analyzed by spectroscopy and viscosity methods. The binding constants of 1 and 2 obtained from UV spectroscopic studies are 5.43 × 105 and 1.83 × 105 M−1, respectively, while the linear Stern–Volmer quenching constants obtained from fluorescence spectroscopic studies are 0.83 × 103 and 0.71 × 103 M−1, respectively. The cyclic voltammograms of the complexes show a pseudo-reversible electrochemical process.

For the purpose of developing an effective Fe2O3-doped nickel-based catalysts to be used in biomass gasification, Fe2O3nanoparticles were prepared by homogeneous precipitation method involving an aqueous solution of Fe (NO3)3·9H2O and urea as precipitator. Different approaches, such as XRD and SEM, were used to characterize the products. Meanwhile, the effects of various technical parameters in preparation process on the yield of products were investigated, and optimal conditions for preparing Fe2O3nanoparticles were found as follows: the molar ratio of urea to Fe (NO3)3·9H2O for 5:1, temperature of precipitation reaction for 125°C, concentration of iron salt for 0.20mol/L. The Fe2O3nanoparticles prepared under the optimal conditions were spherical in shape and well dispersed; they had high purity and a fine crystal phase of cubic syngony with a mean particle size of about 28nm.

nanoAl2O3 has been synthesized by homogeneous precipitation method using dodecyl trimethyl ammonium bromide (DTAB) as surfactant. The as-prepared powder was characterized by FT-IR, XRD, TEM and SEM. The results indicate the surfactant existence in the precursors but disappeared in the products. This is mainly due to the combination of precursor and surfactant, which results in particles of nanosize. The nucleation and growth rate during the precipitation has also been controlled by the addition of surfactant. During the calcination process, the surfactant has decomposed and volatilized into air. The XRD characterization shows the calcined powders were γ-Al2O3 particles with mean size of 27 nm, which was in accordance with TEM characterization. The morphology of the prepared alumina particles has also been investigated by SEM and showed that the powder has a spherical morphology with a uniform particle size.

NiO nanoparticles were successfully prepared by decomposing the predecessor bis(glycinato)nickel(II)dihydrate in the presence of oleylamine and triphenylphosphine (TPP), and different approaches including Fourier transforms infrared spectrometry(FT-IR), X-ray diffraction(XRD) and transmission electron microscopy (TEM) were used to characterize the NiO nanoparticles. Meanwhile, the effects of TPP concentration and reaction time on the size and yield of NiO nanoparticles derived from precursors were thoroughly investigated in this paper. The analysis results indicated that the prepared NiO nanoparticles were found spherical in shape and demonstrated weak agglomeration. They had generally high purity and a fine crystal phase of cubic syngony. Furthermore, the effects of the TPP concentration and reaction time on the size and yield of NiO nanoparticles are very crucial, higher concentration of TPP would results in reduction of both the mean size and yield of NiO particles. However both yields and particles size of NiO nanoparticles continuously increased as increasing reaction time, after more than 60 minutes, the size and yield of NiO nanoparticles kept hardly change.

For the purpose of developing a novel and effective nano-CeO2catalyst used in biomass gasification for tar removal, nanocrystalline CeO2particles were successfully prepared by the homogeneous precipitation method, and different approaches including TG, FT-IR, XRD and SEM were used to characterize the CeO2nano-particles and precursors in this study. The analysis results indicated that the synthesized precursor was hydrated cerium basic carbonates and its formula was identified as Ce2O(CO3)2•nH2O, and it can completely transform into nanocrystalline CeO2particles below 400 °C under the air atmosphere. The prepared CeO2nano-particles were found spherical in shape and well dispersed; they had high purity and a fine crystal phase of cubic syngony structure with a mean size of 13 nm.

To evaluate the molluscicidal effect of black plastic mulching in mountainous areas of Yunnan Province.In Leqiu Village, Nanjian County, Yunnan Province, the terraced fields with Oncomelania hupensis snails were divided into A, B, C, D, E groups, and of which, A, B, C, D groups, as the experimental groups, were administered with simple black plastic mulching for 30 days, 60 days, 90 days and 120 days respectively; Group E, as the control group, was administered with 50% niclosamide ethanolamine salt wettable powder spraying.In Group C and D (simple black film mulching for 90 days and 120 days), no snails were found after the administration, the average density of living snails decreased by 100%, and the cost of one year was similar to that of the control group.The molluscicidal effect of black plastic mulching is good in mountainous areas.

We utilized the strategy of ‘borrowing SERS activity’, by chemically coating several atomic layers of a Pt-group metal on highly SERS-active Au nanoparticles, to obtain the first SERS (also Raman) spectra of surface water on Pt and Pd metals, and propose conceptual models for water adsorbed on Pt and Pd metal surfaces.

Wang, F.; Zong, Y.Q.; Li, J.F.; Tian, L.Z.; Shang, Z.W.; Chen, Y.S.; Jiang, X.Y.; Yang, J.L.; Yang, B., and Wang, H., 2016. Recent sedimentation dynamics indicated by 210Pbexc and 137Cs records from the subtidal area of Bohai Bay, China. To determine sedimentation rate changes across an open marine area along the west coast of Bohai Bay, more than 50 short sediment cores were collected and analyzed with their sedimentation rates estimated by excess 210Pb (210Pbexc) and 137Cs in the sediment. The surveys enabled us to explore the relationship between sediment supply changes from the rivers and the spatial/temporal deposition patterns in the shallow marine areas. Several core records show that sedimentation rates can be overestimated by the conventional constant initial concentration model based on the 210Pbexc curves alone. The overestimation was caused by a change of 210Pbexc in the top layers of these cores and this is confirmed by comparing 210Pbexc curves with the respective 137Cs curves. This...