水热法制备Cu_2O微球

以氯化铜和氢氧化钠为原料,抗坏血酸为还原剂,用水热法制备了Cu2O微球。用X射线衍射(XRD)和扫描电子显微镜(SEM)对产物的结构和形貌进行了表征,结果表明抗坏血酸含量对产物有很大影响。当反应温度为100℃、反应时间为8h、氯化铜和抗坏血酸摩尔比为3:1时,所制备的产物约为300～500nm的类球形颗粒。     

稠油污水膜法资源化预处理技术研究

为解决稠油污水膜法资源化的预处理问题,采用气浮和生物接触氧化除油、砂滤除悬浮物和超滤去除大分子污染物的工艺作为反渗透的预处理工艺。结果表明,气浮可有效去除悬浮油,保证生化进水含油量小于20 mg/L;生物接触氧化可以将含油量降到1 mg/L以下,COD稳定在100 mg/L以下;砂滤的最佳过滤压力为0.6 MPa,砂滤出水的悬浮物小于5 mg/L;超滤的运行压力为0.3 MPa,超滤出水SDI小于3,浊度小于0.2 NTU。     

Porphyrins modified with a low-band-gap chromophore for dye-sensitized solar cells

Two novel porphyrin dyes (PMBTZ and PHBTZ) modified with alkyl-thiophene and 2,1,3-benzothiadiazole (BTZ) moieties were designed and synthesized. The optical and electrochemical properties were characterized by UV-visible, fluorescence spectroscopy and cyclic voltammetry. With the introduction of the low-band-gap chromophore onto the porphyrins, the absorption spectra of the two porphyrin dyes in the range of 450-600 nm were broadened and the maximum wavelength was red-shifted compared with P_Zn as expected. The first oxidation potentials (E_ox1) were altered to the negative, which lowered from 1.27 to 1.11 and 1.15 eV, respectively. For a typical solar cell device based on dye PMBTZ, the maximal monochromatic incident photon-to-current conversion efficiency (IPCE) can reach to 65%, with a broad respondent region of 350-800 nm. Under standard global AM 1.5 solar condition, the dye-sensitized solar cell (DSSC) based on the dye PMBTZ showed the best photovoltaic performance: a short-circuit photocurrent density (J_sc) of 14.11 mA/cm², an open-circuit photo voltage (V_oc) of 0.59 V, and a fill factor (ff) of 0.66, corresponding to solar-to-electric power conversion efficiency (η) of 5.46%.     

黑曲霉HQ-1产羧甲基纤维素酶的发酵条件优化

采用单因素试验和响应面法对黑曲霉(Aspergillus niger)HQ-1产羧甲基纤维素酶(CMC酶)的固体发酵条件进行了优化。结果表明,产酶的最佳发酵条件为:玉米秸秆粉6.0 g、麦麸6.0 g(、NH4)2SO4 1.5 g、KH2PO4 1.6 g、Mg-SO4.7H2O 0.8 g、含水量73.9%、起始pH3.93、培养温度和培养时间分别为34.1℃和96 h。优化后,菌株产CMC酶活力最高为317.103 U/g,比未优化的酶活力最高值(65.507 U/g)提高了3.84倍。     

SmAlO3-modified (K0.5Na0.5)0.95Li0.05Sb0.05Nb0.95O3 lead-free ceramics with a wide sintering temperature range

Lead-free ceramics (1 − x)(K_0.5Na_0.5)_0.95Li_0.05Sb_0.05Nb_0.95O₃-xSmAlO₃ (KNLNS-xSA) were prepared by conventional sintering technique. The phase structure, dielectric and piezoelectric properties of the ceramics were investigated. All compositions show a main perovskite structure, exhibiting room-temperature symmetries of tetragonal at x ≤ 0.0075, of pseudo-cubic at x = 0.0100. The Curie temperature of KNLNS-xSA ceramics decreases with increasing SmAlO₃ content. Moreover, the addition of SmAlO₃ can effectively broaden the sintering temperature range of the ceramics. The KNLNS-xSA ceramic with x = 0.0050 has an excellent electrical behavior of piezoelectric coefficient d₃₃ = 226 pC/N, planar mode electromechanical coupling coefficient k_p = 38%, dielectric loss tan δ = 3.0%, mechanical quality factor Q_m = 60, and Curie temperature T_C = 327 °C, suggesting that this material could be a promising lead-free piezoelectric candidate for piezoelectric applications.     

Facile synthesis and crystal growth dynamics study of MgAl2O4 nanocrystals

Well-dispersed MgAl₂O₄ nanocrystalline was prepared by a convenient salt-assistant combustion process using low-toxic glycine as fuel, low-cost Mg(NO₃)₂·6H₂O and Al(NO₃)₃·9H₂O as raw materials. By changing the reaction condition such as glycine dosage, the amount of inert-salt, inert-salt types and calcinations temperature, the optimal conditions to synthesize MgAl₂O₄ nanocrystalline were explored. The obtained results showed that parameters inert-salt and fuel dosage in the process have an important effect on the structure properties of samples. The obtained products were characterized by XRD and TEM. TEM images revealed that the products were composed of well-dispersed cube-like nanocrystals with the size of 60–80 nm. The synthesis mechanism of MgAl₂O₄ nanocrystals was discussed. The crystal growth dynamics of MgAl₂O₄ nanocrystals was studied and the activation energy of MgAl₂O₄ nanocrystals was 39.1 kJ/mol.     

一类解决Job Shop问题的禁忌搜索算法

针对Job shop问题，设计了一种改进的禁忌搜索算法（MTS算法）。MTS算法从多个初始解开始，将传统禁忌搜索算法由串行搜索结构变为并行搜索结构；采用互换和交叉两种邻域搜索函数，既有利于新邻域的探索又有利于交换信息；基于目标值的禁忌表保证了群体的多样性。实验表明，MTS算法克服了传统禁忌搜索算法的缺陷，具有较高的求解质量和鲁棒性。     

解决无等待流水线调度问题的变邻域搜索算法

提出了解决无等待流水线调度问题的变邻域搜索调度算法。采用基于自然数编码的工件序列表达问题的解，采用多重Insert移动邻域和多重Swap移动邻域作为变邻域搜索的两种邻域结构。多重移动有利于算法向包含较优解的区域搜索，因而有较高的求解质量和效率。仿真实验证明了变邻域搜索算法的有效性。     

Electrosyntheses and characterizations of novel electrochromic and fluorescent copolymers based on 2,2′-bithiophene and pyrene

Poly (2,2′-bithiophene-co-pyrene), a novel copolymer, is successfully achieved by electrochemical oxidation of the monomer mixtures of 2,2′-bithiophene (BT) and pyrene in acetonitrile (ACN) containing sodium perchlorate (NaClO₄). FT-IR and ¹H NMR characterizations support that the obtained copolymers contain both pyrene and BT units. A series of experiments are carried out to investigate the properties of the copolymers obtained from 0.2 M NaClO₄/ACN with different monomer feed ratios. The electrochemical properties of the obtained copolymers are studied by cyclic voltammetry (CV). Compared with polypyrene, the copolymers perform reversible redox process. Elemental analyses results indicate that the ratio of BT/pyrene units in copolymers increases as the feed ratio of BT/pyrene increases. The obtained copolymers also present properties of tunable electrochromism, good thermal stability and smooth morphology. The UV-vis absorption peaks of the copolymers exhibit obvious red-shift. Fluorescence spectra studies reveal that the copolymer is a good green-light emitter.     

The degradation and prestabilization of acrylonitrile copolymers

The degradation and prestabilization of polyacrylonitrile (PAN) were investigated with differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). The initial temperature, initial loss‐weight temperatures, and loss‐weight were significantly lowered when ammonium itaconate (AIA) was used as comonomer. One exothermal peak of PAN (homopolymer) was shown in the DSC curves, while there were four exothermal peaks of poly(AN‐AIA). FTIR spectra results confirm the degradation process of NH groups. During the heating process, NH groups (3030 cm^?1) were changed into NH (2955 cm^?1) and then NH groups (2920 cm^?1). The dissociated H⁺ could initiate the cyclization reactions of C?N companied with heat released. The effect of ammonia on degradation and prestabilization of PAN was also studied. It was found that ammonia could accelerate prestabilization of acrylic precursors. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010