多环芳烃生物降解及转化途径的研究进展

多环芳烃(PAHs)作为一种持久性有机污染物,因其危害性突出备受关注,微生物降解作为一种高效的修复手段,逐渐成为环境修复领域的研究热点,综述PAHs生物降解及转化途径的国内外研究进展,以期为今后深入分析PAHs降解机理奠定理论基础。以萘(Nap)、菲(Phe)、苯并［a］芘(BaP)等典型PAHs作为研究对象,并结合微生物的生长环境,阐述好氧微生物与厌氧微生物对PAHs的生物降解和转化途径。研究表明,细菌、真菌及古菌对PAHs均有一定的降解效能,其中,细菌对PAHs降解能力优于真菌和古菌,而且可通过双加氧酶氧化过程及羧化、甲基化或羟化等还原途径实现PAHs降解。     

ZSM-5/MgO质量比对复合催化剂物化性质及合成甲硫醇反应的影响

采用介孔碱性MgO对微孔酸性ZSM-5分子筛进行复合改性,利用液相沉淀包覆技术制备了ZSM-5/MgO复合催化剂,研究了ZSM-5与MgO质量比对复合催化剂物化性质和合成甲硫醇催化性能的影响。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、比表面积及孔隙分析仪(BET)和化学吸附分析仪(CO₂/NH₃-TPD)等手段对不同复合催化剂的晶相组成、微观形貌、孔结构及表面酸碱性进行分析表征。结果表明：ZSM-5/MgO质量比对ZSM-5/MgO复合催化剂的物化性质和催化性能影响较大。过高或过低ZSM-5/MgO质量比制得复合催化剂中MgO结晶度都有所降低,且未形成包覆相结构;ZSM-5/MgO质量比为1/3时制得复合催化剂形成了均匀包覆相结构和微 介孔结构(总比表面积为162 m²/g,总孔体积0.46 cm³/g),同时具有酸碱特性;在反应压力1.0 MPa、反应温度370  ℃、H2S/CH₃OH摩尔比2/1、N₂流速80 mL/min、H₂S流速4.9 mL/min反应条件下合成甲硫醇,复合催化剂表现出优越的催化性能、稳定性及寿命,CH₃OH转化率、CH₃SH选择性和CH₃SH收率分别达到90.48%、90.04%和81.47%,催化剂寿命达到18 h。与单一ZSM-5分子筛相比,复合催化剂寿命延长了7 h,CH₃SH收率提高了13.97百分点。     

Inorganic–organic hybrid material containing β-cage: {[H2(en)]Co2(ox)(V4O12)}n

By using an organic ligand, a new inorganic–organic hybrid compound of cobalt oxalate-vanadate, {[H₂(en)]Co₂(ox)(V₄O₁₂)}_n 1, where en = ethylenediamine, ox = oxalic acid, has been synthesized hydrothermally from V₂O₅,CoCl₂·6H₂O,H₂C₂O₄·2H₂O and en. Crystal data 1, orthorhombic, Cmcm space group, a=11.624(2), b=9.968(2), c=14.900(3) Å, R1=0.0298, wR2=0.1172. Compound 1 possesses a three-dimensional open-framework with β-cage and is an antiferromagnetic matter.     

Formation and properties of Zr48Nb8Cu14Ni12Be18 bulk metallic glass

Zr₄₈Nb₈Cu₁₄Ni₁₂Be₁₈ bulk metallic glass (BMG) with excellent glass-forming ability was prepared by water quenching method. The BMG exhibits high glass transition temperature T_g and onset crystallization temperature T_x, compared with Zr₄₁Ti₁₄Cu_12.5Ni₁₀Be_22.5 BMG. The crystallization processes, change of elastic constants, and density and hardness in the crystallization process were studied by using X-ray diffraction, differential scanning calorimetry and acoustic method. The shear modulus, Poisson ratio, density and hardness are found to be sensitive to the crystallization process. A striking softening of long-wavelength transverse acoustic phonons in the BMG relative to its crystallized state is observed. The linear expansion coefficient, determined by a dilatometer method, is α_TG=1.04×10⁻⁵ K⁻¹ (300–656 K) for the BMG and α_TC=1.11×10⁻⁵ K⁻¹ (356–890 K) for the crystalline alloy. The Mie potential function and the equation of state of the BMG are determined from the expansion coefficient and acoustic experiments.     

Out-of-plane deflection of nonprismatic curved beam structures solved by DQEM

The differential quadrature element method (DQEM) is used to solve the out-of-plane deflections of nonprismatic curved beam structures. The extended differential quadrature is used to discretize the governing differential equations defined on all elements, the transition conditions defined on the inter-element boundary of two adjacent elements and the boundary conditions. Numerical results obtained by DQEM are presented. They demonstrate the developed numerical solution procedure.     

黔北正安区块牛栏组基于叠后地震属性的多尺度裂缝预测

黔北正安地区安场向斜石牛栏组为一套深水陆棚沉积的泥灰岩地层,前期钻探显示,石牛栏组气藏分布与裂缝发育程度密切相关,为典型的裂缝型气藏。为进一步对安场向斜石牛栏组储层的裂缝平面展布规律进行研究,该文通过岩心、成像测井等资料分析目的层的裂缝发育特征,优选裂缝预测敏感地震属性,基于地震像素处理的裂缝增强属性对石牛栏组裂缝分布进行了预测。研究结果表明:利用常规的地震曲率属性预测裂缝识别能力有限,而基于地震像素处理的地震数据能够有效改善小断层及构造形变特征成像,在此基础上开展的裂缝增强属性可大大提高裂缝的识别能力,经实钻井验证,基于叠后地震属性裂缝分布预测方法的结果与钻井泥浆漏失点综合吻合率达83.3%以上,预测结果较为可靠,该研究为石牛栏组区带优选及钻井风险预警提供了技术支撑。     

抑烟除味剂对SMA-13沥青混合料路用性能影响评价

选用SMA-13级配,通过添加抑烟除味剂来改善热拌沥青施工环境,研究其对沥青及其混合料性能影响,并评价了抑烟除味剂对于沥青烟的降解效果。结果表明,抑烟除味剂的添加降低了施工、拌和温度并且减少了烟气的排放,同时其沥青及混合料的路用性能均满足热拌沥青混合料相关规范要求。     

Shielding behaviour of conducting polymer-coated fabrics in X-band,W-band and radio frequency range

Electromagnetic interference response of conducting polyaniline-coated fabrics in the microwave range, W-band, RFI range as well as in UV–Vis–NIR range has been studied. In the radio frequency range from 100 to 1000 MHz, conducting polyaniline-coated fabrics shows a shielding effectiveness in the range 30–40 dB. Shielding effectiveness of the conducting fabrics in W-band region at 101 GHz shows an attenuation of 35.61 dB. The microwave reflectance studies of the coated fabrics in 8–12 GHz range shows that conducting fabrics gives shielding effectiveness value of −3 to −11 dB. The reflectance studies of conducting polyaniline-coated fabric shows that 98% of the energy is absorbed in the UV–Vis–NIR range and 2% is reflected back. In polypyrrole-coated fabric 96% of energy is absorbed and 4% is reflected back, whereas in substituted polythiophene-coated fabric, 82% of the energy is absorbed and 18% is reflected back.     

Self-organization processes in semiconductor under photo-induced Gunn effect

Theoretical investigation of self-organization of non-equilibrium carriers system in n-GaAs under photo-stimulated Gunn effect was performed. It was shown that the behavior of carrier system could be controlled using incident light intensity resulting in different oscillation regimes. Results obtained allow us to predict application ranges for devices working on the phenomena investigated.