Combustion synthesis of LaSi3N5:Eu2+ phosphor powders

LaSi₃N₅:Eu²⁺ phosphor powders were prepared by a highly efficient combustion synthesis method. It was found that the compositions of the raw powder mixtures had great influences on the phase compositions and particle morphologies of the synthesized powders. By selecting appropriate starting compositions and combustion parameters, single phase LaSi₃N₅:Eu²⁺ phosphors could be synthesized. When excited by a UV light, the LaSi₃N₅:Eu²⁺ phosphors emitted green light. The wavelength and intensity of the emission spectra were affected by the amount of Eu²⁺ dopant. With increasing amount of Eu²⁺ dopant, concentration quenching could occur and emission spectra shifted to longer wavelengths.     

五脉相通——南京中胜公路客运站设计

通过对南京中胜公路客运站设计的分析和研究,探讨和总结了公路客运站在选址、规划布局、交通组织、内部坪面组织等方面的规律和特点.     

Influence of cooling rate after homogenization on microstructure and mechanical properties of aluminum alloy 7050

The influence of cooling rate (0.009?C220 °C/s) after homogenization on the microstructure and mechanical properties of high strength aluminum alloy 7050 was investigated by tensile testing, optical microscope, X-ray diffraction, scanning electron microscope, and transmission electron microscope. A lower cooling rate after homogenization resulted in lower mechanical properties after aging. The drop in strength was significant when the cooling rate was decreased from 0.5 °C/s to 0.1 °C/s. A lower cooling rate gave rise to a larger amount of remnant S(Al₂CuMg) phase and a higher fraction of recrystallization after solution heat treatment. Consequently, the increase in strength after aging due to precipitation hardening and substructure hardening was less significant in the case of slow cooling. This was supposed to be responsible for the lower mechanical properties due to a lower cooling rate after homogenization.     

Real-Time Path Planning Based on the Situation Space of UCAVs in a Dynamic Environment

This paper aims to find a reliable, collision-free path in a dynamic environment for highly maneuverable unmanned combat air vehicles (UCAVs). Given the real-time nature of the operational scenario, quick and adaptable reactions of UCAVs are necessary for updates in situational awareness. Therefore, we propose a three dimensional (3D) path planning approach based on the situational space to provide the tactical requirements of UCAVs for tracking targets and avoiding collisions. First, to ensure reliable nonlinear measurements, the interacting multiple model (IMM) algorithm based on a cubature Kalman filter (CKF) is chosen for the tracking and prediction algorithm. A constraint reference frame combining the kinematic model of constant acceleration (CA) is developed to solve the problem of arrival point generation. Second, by analyzing the relative motion between the UCAV and the moving objects, we define the situation space and give the corresponding calculation method. In tracking the moving target, the guidance vector contains the fusion information of displacement and velocity. At the same time, taking advantage of the one-step situation space as the judgment of the threat, we further plan the collision avoidance strategy. Third, as the safety in a practically reachable trajectory of the UCAV possesses the absolute priority, the collision avoidance acceleration accounts for this dominant factor in path planning. Simulations and experimental results prove that the proposed approach can plan a smooth and flyable path in 0.008 s under the premise of soft-landing target tracking.     

新钢10#高炉异常炉况快速恢复

江西新钢10#高炉在强化冶炼的过程中炉况发生异常，通过采取活化炉缸，发展中心为主导气流，加强炉前管理等措施，大大缩短了高炉的恢复时间，将损失降低到了最低水平。     

外墙渗漏的主要原因及预防措施

外墙渗漏直接影响到建筑物的使用功能,也严重影响建筑物的观感效果,是工程质量长期治理的顽症之一。文章以某学校教学楼墙面渗漏为例,全面分析了引起渗漏的原因,并提出防治墙面渗漏的具体措施。     

Cr12MoV冷作模具失效分析

对Cr12MoV作模具开裂的原因进行了分析。结果表明:模具锻造不充分,残留了带状碳化物,使模具淬火加热时奥氏体成分不均匀,淬火冷却时产生过大的组织应力和热应力,造成模具早期开裂。     

Development of microbial fuel cell with anoxic/oxic design for treatment of saline seafood wastewater and biological electricity generation

BACKGROUND: Sustainable technologies need to be developed to treat saline seafood wastewater (SSW) efficiently. This study focused on the feasibility of a continuously operated microbial fuel cell (MFC) with modified anoxic/oxic (A/O) architecture (A/O–MFC) for power generation and treatment of SSW simultaneously. RESULTS: Hydraulic retention time (HRT) was shown to have an impact on polarization and power output of the A/O–MFC and the maximum power density of 16.2 W m^?3 was obtained at a current density of 41.7 A m^?3 and HRT of 4.2 h. High salinity together with advective flow mode enabled a low and constant internal resistance of approximately 100 Ω throughout the experiments. Besides, pH of waste stream in both compartments was found always near neutral level. Increasing HRT could improve eliminability of soluble chemical oxygen demand (sCOD) and biological nitrification. CONCLUSIONS: This study provides a proof‐in‐concept demonstration to utilize an MFC for effective and sustainable treatment of SSW along with recovery of electrical energy. Copyright © 2010 Society of Chemical Industry     

Evaluation of fly‐ash additive for removal of dissolved organic matter during soil aquifer treatment of wastewater treatment plant Peffluent

BACKGROUND: Fly‐ash (FA) additive was evaluated for enhanced removal of organic matter during soil aquifer treatment (SAT) of a wastewater treatment plant (WWTP) effluent in five 0.50 m length columns (diameter 0.1 m) in parallel. RESULTS: The characteristic behavior of dissolved organic matter (DOM) was examined for the stratum matrix configurations of both natural soil and a mixture of soil and FA. Incubation and fractionation experiments indicated that FA additive within the SAT columns would enhance the bulk adsorption of hydrophobic fractions, but decrease the biodegradation of the hydrophilic fraction simultaneously. The configuration design of an upper 0.25 m soil layer and a mixture of FA and soil underneath could make use of the functions of both FA adsorption and biodegradation within soil, which could lead to a further fractional removal of dissolved organic carbon (DOC) and trihalomethane formation potential (THMFP). Moreover, FA additive in the SAT columns could result in a significant decrease of tryptophan‐like aromatic proteins and fulvic‐like components (C?C and C?O related), while the setting of the top 25 cm soil layer would lead to a further reduction of oxygen‐containing functional groups. CONCLUSIONS: Based on the results, FA might serve as a supplementary material for enhancing the reduction of DOM during SAT operation. Copyright © 2010 Society of Chemical Industry     

In situ crosslinking of hyperbranched polyglycerol in casting solutions and its effect on the structure and properties of porous PVDF membranes

Porous membranes were prepared via phase inversion process from casting solutions composed of poly(vinylidene fluoride), hyperbranched polyglycerol (HPG), and N,N‐dimethylacetamide. To seek a stable presence of HPG in the resulting membranes, it was crosslinked in the casting solutions using 4,4′‐oxydiphthalic anhydride as the crosslinking agent. The membranes were characterized in terms of morphology, surface and bulk chemical compositions, water contact angle, porosity, water flux, and bovine serum albumin (BSA) adsorption experiments. The effects of HPG content and crosslinking degree on the membrane structure and properties were investigated. The increasing of crosslinking degree resulted in a significant improvement in HPG stability in the membrane matrix, and a remarkable enrichment of the crosslinked HPG at the separation surface was observed when the membrane was shaken in water at a relatively high temperature (60°C). This enrichment led to a decrease in the value of water contact angle and an improvement in fouling‐resistance. To optimize the membrane performance, a small amount of poly(vinylpyrrolidone) (PVP) was used as an additive, and it was found that the addition of PVP led to a considerable increase in water flux. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010