生活污水脱氮的A/O/N工艺和A/O工艺对比试验研究

为提高传统生物脱氮工艺的脱氮水平,在分析传统生物脱氮工艺局限性的基础上提出了传统A/O工艺的改良工艺即A/O/N工艺。通过采取相同能耗条件下最佳工艺参数的对比试验研究,试验结果表明两工艺对CODCr去除效果均较好,A/O/N工艺对NH3-N和TN的去除效果明显优于A/O工艺,且耐NH3-N冲击负荷更强。     

O1/A1/O2/A2工艺处理焦化废水试验研究

通过对短程硝化反硝化工艺的研究,开发了好氧/厌氧/好氧/缺氧(O1/A1/O2/A2)生物脱氮新工艺并用于焦化废水的处理。考察了NH4+-N、COD、TN对反应器运行效果影响。结果表明,当进水COD平均为3 012.9 mg/L,NH4+-N、TN、挥发酚、总氰平均质量浓度分别为590.5、608.4、361.8、34.5 mg/L;出水COD平均为81.7 mg/L,出水NH4+-N、TN、挥发酚、总氰的平均质量浓度分别为0.1、9.9、0.1、0.1 mg/L,出水指标达到国家污水综合排放一级标准,A/O工艺处理这种焦化废水TN偏高,而用O1/A1/O2/A2工艺可以解决这一问题,实现了TN脱除。考察了温度、DO、pH对短程硝化影响。结果表明,在DO质量浓度为1.0～1.5 mg/L、温度在30～35℃、pH 7.5～8.0,系统能够进行稳定短程硝化反硝化。     

应用A/A/O工艺改造焦化厂废水处理站

以萍乡钢铁有限责任公司焦化厂焦化废水处理站改造为例,比较了在焦化废水生物脱氮中应用最广泛的A/O工艺和A/A/O工艺,介绍了应用A/A/O工艺对对焦化厂焦化废水处理站进行生物脱氮改造的方案及其主要特点。投产后的进出水水质分析结果表明应用A/A/O工艺处理后的焦化废水能达到排放标准。     

厌氧/好氧/缺氧(A/O/A)工艺处理焦化废水的试验研究

考察了厌氧/好氧/缺氧(A/O/A)工艺处理焦化废水对COD和NH3-N的去除效果。连续试验表明,焦化废水进水CODCr、NH3-N平均浓度分别为2 450 mg/L、121 mg/L,在经过系统稳定运行处理后出水浓度分别为115 mg/L、10.6 mg/L,去除率分别为95.3%、91.2%,达到了《污水综合排放标准》的二级标准。将厌氧池和缺氧池内的出气作为气源放回曝气池中,在缺氧环境下形成气升循环。好氧池为气提升三相循环流化床结构,不设沉淀池,MLSS高达10~12 g/L。     

废报纸粉填充聚丙烯材料的研究

本文介绍废报纸粉填充聚丙烯（ＰＰ）的研制。通过在体系中加入高分子偶联剂马来酸酐（ＭＡＨ）接枝ＰＰ（ＭＡＰＰ）来改善纸粉与ＰＰ基体的相容性，并针对纸粉填充后材料变脆的问题，用乙丙橡胶（ＥＰＤＭ）和乙烯醋酸乙烯共聚物（ＥＶＡ）对材料进行增韧，均取得显著的效果。所制材料的纸粉填充量（质量分数）可高达５０％～６０％，价廉、质轻、其主要性能好于桑塔纳轿车用木粉填充ＰＰ板，可望有较好的应用前景。当纸粉填充量（质量分数）为４０％～５０％时，主要性能：弯曲强度６９．０１～７４．８３ＭＰａ，杨氏弯曲模量２６４０～２９９６ＭＰａ，冲击强度１３．２５～１３．５０ｋＪ／ｍ２。     

A new NOx storage-reduction electrochemical catalyst

A new NO_x storage-reduction electrochemical catalyst has been prepared from a polycrystalline Pt film deposited on 8 mol% Y₂O₃-stabilized ZrO₂ (YSZ) solid electrolyte. BaO has been added onto the Pt film by impregnation method. The NO_x storage capacity of Pt-BaO/YSZ system was investigated at 350 °C and 400 °C under lean conditions. Results have shown that the electrochemical catalyst was effective for NO_x storage. When nitric oxides are fully stored, the catalyst potential is high and reaches its maximum. On the other hand, when a part of NO and also NO₂ desorb to the gas phase, the catalyst potential remarkably drops and finally stabilizes when no more NO_x storage occurs but only the reaction of NO oxidation into NO₂. Furthermore, the investigation has clearly demonstrated that the catalyst potential variation versus temperature or chemical composition is an effective indicator for in situ following the NO_x storage-reduction process, i.e. the storage as well as the regeneration phase. The catalyst potential variations during NO_x storage process was explained in terms of oxygen coverage modifications on the Pt.     

A Novel Lead Titanate, PbTi3O7

The TiO₂-rich side of the system PbO-TiO₂ was investigated by X-ray diffraction techniques, and a new compound PbTi₃O₇ was found. It has a bimolecular monoclinic unit Cell with a = 10.732 A, b = 3.812 A, c = 6.578 A, and β= 98° 05'. The PbTi₃O₇ decomposes into PbTiO_s and rutile at temperatures above 850°C. The overall decomposition proceeds according to first-order kinetics with an apparent activation energy of about 170 kcal mole^-1.     

A~2/O工艺在高原地区污水处理工程中的应用

根据西藏藏木水电站营地特殊的地理环境和气候特征以及生活污水水质特点和处理要求,经过污水处理方案对比分析,采用A2/O工艺和重力无阀滤池处理该营地的生活污水,污水单位投资为0.52万元/m3,污水单位处理成本为0.73元/m3,污水经过处理达标后全部回用。     

焦化废水生物处理A/O/H/O工艺中氰化物的去除特性

针对焦化废水处理工程设计过程中极少涉及基于氰化物浓度变化与考察分析的实际问题,通过对已经运行的广东韶钢集团焦化废水处理工程统计数据的辨析,提出实现总氰化物高效去除的技术与运行强化方法。分析数据发现,在降解的过程中,氰化物滞后于酚类代表的有机物,络合氰的降解比游离氰慢,生物处理过程中由水力停留时间控制的碳源利用与金属离子的存在影响氰化物的降解,而A/O₁/H/O₂工艺在有效分配除碳过程与脱氮过程中实现了氰化物的高效降解。进一步工程实践证明,焦化废水处理全部指标达标的高效性可以通过充分考虑复杂组分降解动力学的协同与优化操作条件加以实现。     

A New Low-Loss Microwave Dielectric Ceramic Sr4LaTiNb3O15

A high dielectric constant and low-loss ceramic with composition Sr₄LaTiNb₃O₁₅ has been prepared by the conventional solid-state ceramic route. This compound adopts an A₅B₄O₁₅ cation-deficient hexagonal perovskite structure and crystallizes in the trigonal system with unit cell parameters a =5.6307(2), c =11.3692(3) Å, V =312.16(2) ų, and Z =1. The dielectric properties of dense ceramics sintered in air at 1460°C have been characterized at microwave frequencies. The results show that the material affords a relatively high dielectric constant ɛ_r∼43, a high quality factor Q × f ∼44 718 GHz, and a low temperature coefficient of resonant frequency TC_f∼13 ppm/°C.     

A New Ternary Nanolaminate Carbide: Ti3SnC2

We report on the synthesis of Ti _{n +1}SnC _n (MAX phases) by hot isostatic pressing starting with titanium, tin, and carbon powders. In addition to the already known Ti₂SnC compound (211 MAX phase), a new 312 MAX phase, Ti₃SnC₂, is formed. Its lattice parameters, deduced from Rietveld analysis of X-ray diffraction patterns, are found to be a =0.31366 nm and c =1.8650 nm.     

Swelling of Hot-Pressed A12O3

Fully dense aluminas, prepared by hot-pressing, were found to swell during annealing at 1600°C in air, but not during annealing in a reducing atmosphere (po₂= 10^-7 Pa). The reaction followed the relation p - po = -K log t, where p_o and p are the initial and final densities, respectively, t is the time, and AT is a constant. The rate of swelling was enhanced by MgO solute. The reduction in density resulted from the nucleation and growth of grain-boundary pores. Pore formation was attributed to the reaction of carbon and sulfur impurities at the boundaries with oxygen, which had diffused down the grain boundaries from the ambient, to form CO/CO₂ and SO₂ gas at high pressures. Preliminary results indicate that this reaction can be avoided by preannealing powders in flowing oxygen prior to hot-pressing. The consequences of internal gas-forming reactions to other processes such as high-temperature creep and sintering are also discussed.     

Ba8ZnTa6O24: A New High Q Dielectric Perovskite

The hexagonal perovskite, Ba₈ZnTa₆O₂₄, was prepared in single-phase form and was found to be a stable secondary phase, formed as a result of the loss of ZnO from Ba(Zn_1/3Ta_2/3)O₃ microwave dielectrics. The experimental and calculated X-ray patterns of Ba₈ZnTa₆O₂₄ indicate it is isostructural with Ba₈Ta₆NiO₂₄ with an 8H (cchc)₂ close-packed BaO₃ stacking sequence and the lattice parameters, a =10.0825(14), c =19.0587(38)Å. High-density ceramics of Ba₈ZnTa₆O₂₄ could be prepared at temperatures considerably lower (1400°C) than those used to sinter pure Ba(Zn_1/3Ta_2/3)O₃, and exhibit very good microwave dielectric properties with ɛ=30.5, Q _f=62 300, and τ_f=+36 ppm/°C at 8.9 GHz.     

A Chemical Route to BiNbO4 Ceramics

The liquid phase sintering of fine BiNbO₄ powders allows to obtain dense ceramics with excellent microwave dielectric properties (ɛ=44–46; Q × f =16,500–21,600 GHz) at T ≥700°C. The thermal decomposition of freeze-dried precursors results in the crystallization of a metastable β'-BiNbO₄ polymorph that transforms into a stable orthorhombic α-modification at T ≥700°C. The dependence of sinterability on the powder synthesis temperature shows the maximum at 600°C, corresponding to the formation of crystalline BiNbO₄ powders with a grain size 80–100 nm. Sintering temperature reduction to 700°C prevents the deterioration of silver contacts during co-firing with BiNbO₄ ceramics. In situ scanning electron microscopy observation of the morphological evolution during sintering shows that the intense shrinkage soon after the appearance of a CuO–V₂O₅ eutectics-based liquid phase is accompanied by complete transformation of the ensemble of primary BiNbO₄ particles.     

AS／EVA／NBR共混体系研究

本文研究了ＡＳ／ＥＶＡ／ＮＢＲ共混体系性能与组成比，形态结构的关系；并研究了ＮＢＲ组成对共混体系性能的影响。结果表明ＥＶＡ可作为ＡＳ与ＮＢＲ的相容剂；适量ＥＶＡ可以大幅度提高共混物的冲击韧性，且可改善制品外观；共混物具有优良的常，低温冲击韧性。较好的其它力学性能性。ＴＥＭ观察结果揭示ＥＶＡ的加入可使ＮＢＲ颗粒分布均匀，粒径变小；部分ＥＶＡ处于ＮＢＲ颗粒与ＡＳ基本相界面上，起着相容的作用。     

Identification of BaO. A12O3.5TiO2 in the Ternary System BaO. A12O3-TiO2

A new identification and indexing for the phase BaAl₂Ti₅O₁₄ were accomplished using an X-ray diffraction technique. The new lattice parameters for the tetragonal lattice structure are: a₀=9.990 × 10^-10 m and c₀=12.264 × 10^-10 m, with a corresponding volume 1.224 × 10^-27 m³. The data provided by the Joint Committee on Powder Diffraction Standards are inconsistent both in lattice parameter values and Miller indices. The X-ray powder diffraction pattern of BaAl₂Ti₅O₁₄ was indexed using the LSUCR (least-squares unit cell refinement) computer program.     

Nanogold/Polyaniline/Penicillin G Nanoconjugates: A Novel Nanomedicine

A novel strategy was developed for one-step synthesis of PANI/gold nanoconjugates to develop new resistant penicillin G molecules. Spherical monodispersed PANI/gold colloids were prepared by a photochemical reaction between aqueous gold chloride solution and acidic polyaniline solution. Functionalized PANI/gold colloids were then grafted to the C3 carboxyl group of the β lactam ring of penicillin in the presence of N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide hydrochloride (EDAC) with a conjugation yield of 175 µg mg^?1. These novel gold penicillin G nanoconjugates showed a very good growth inhibition against β lactam resistant Staphylococcus aureus (gram positive). This work thus describes a novel strategy for one step synthesis of PANI/gold colloids to develop resistant antibiotic nanoconjugates as novel bactericidal materials.     

A Theoretical Estimate of Solution-Precipitation Creep in MgO-Fluxed Si3N4

The creep rate in MgO-fluxed hot-pressed Si₃N₄ is calculated by means of a model which assumes a solution-precipitation mechanism, and by using the kinetic data for the dissolution rate of β-Si₃N₄ in an Mg-Si-O-N glass (which was obtained in independent experiments). Despite simplifying assumptions, the predictions match quite favorably with experimental measurements of creep in hot-pressed Si₃N₄.     

Preparation of Cubic Perovskites A(B2/5W3/5)O3 (A=Ba or Sr, B=Na or Li)

Pure cubic perovskites Ba(Na_2/5W_3/5)O₃, Sr(Na_2/5W_3/5)l5)O₃, and Sr(Li_2/5W_3/5)O₃ were prepared by solid-state reaction at 600° to 650°C in air, by starting with oxides or carbonates of the various elements. The cubic forms have an ordered arrangement of the B cations in the ABO₃ structure, and the lattice constants are a =0.8324 nm [Ba(Na_2/5W_3/5)O₃], 0.8136 nm Sr(Na_2/5W_3/5)O₃], and 0.7958 nm [Sr(Li_2/5W_3/5)O₃]     

Al2TiO5-ZrTiO4-ZrO2 Composites: A New Family of Low-Thermal-Expansion Ceramics

The characterization and properties of ceramic composites containing the phases Al₂TiO₅, ZrTiO₄, and ZrO₂ are described. The range of compositions investigated gives very low average thermal expansions (α_24–1000°C as low as −2.0 × 10⁻⁶°C⁻¹) and excellent high-temperature stability. The low thermal expansions are apparently due to a combination of microcracking by the titanate phases and a contractive phase transformation by the ZrO₂. The crystal chemistry and microstructure of the product are processing dependent. Although the composites represent a complex microcracking system, the low thermal expansions and high-temperature stability make them potential candidates for commercial applications requiring thermal shock resistance.