无线智能网技术

本介绍CDMA无线智能网（WIN）的产生背景、技术标准、提供的业务、与GSM移动智能网技术上的差异以及它在实际工程中的应用，最后对WIN的发展进行展望。     

燃烧—气体容量法测定冶金石灰中的二氧化碳

冶金石灰是石灰石经过工业煅烧的产品。其二氧化碳含量低，且经过高温煅烧后基本不含有机物。无需按照《石灰石、白云石化学分析国家标准中二氧化碳的化学分析方法》中用酸进行试样分解，只需在1200℃高温中灼烧，使石灰中残留的或煅烧后吸收空气中二氧化碳而形成的碳酸盐分解，象通常测定含碳耐火材料中二氧化碳那样，采用气体容量法进行测定。     

MoSi2发热体在熔铝炉中的运用

以电阻熔铝炉技术改造实践为例，介绍一种高效、节能、不渗铁的新型熔铝炉——二硅化钼熔铝炉的设计。     

用环境友好催化剂合成丙酸异丁酯的研究

报道了以固载杂多酸盐TiSiW12O40/TiO2为环境友好催化剂，对以丙酸和异丁醇为原料合成丙酸异丁酯的反应条件进行了研究。实验表明：TiSiW12O40/TiO2是合成丙酸异丁酯的良好催化剂，最佳反应条件为：n（醇）：n(酸）=1.2:1，催化剂用量为反应物料总质量的2.0%。反应时间1.0h，反应温度106-125℃，上述条件下，丙酸异丁酯的收率可达79.1%。     

Morphology and properties of poly[2‐methoxy‐5‐(2′‐ethyl‐hexyloxy)‐para‐phenylene vinylene]/silica nanoparticle hybrid films

Poly[2‐methoxy‐5‐(2′‐ethyl‐hexyloxy)‐para‐phenylene vinylene] (MEH‐PPV)/silica nanoparticle hybrid films were prepared and characterised. Three kinds of materials were compared: parent MEH‐PPV, MEH‐PPV/silica (hybrid A films), and MEH‐PPV/coupling agent MSMA/silica (hybrid B films), in which MSMA is 3‐(trimethoxysilyl) propyl methacrylate. It was found that the hybrid B films could significantly prevent macrophase separation, as evidenced by scanning electron and fluorescence microscopy. Furthermore, the thermal characteristics of the hybrid films were largely improved in comparison with the parent MEH‐PPV. The UV‐visible absorption spectra suggested that the incorporation of MSMA‐modified silica into MEH‐PPV could confine the polymer chain between nanoparticles and thus increase the conjugation length. The photoluminescence (PL) studies also indicated enhancement of the PL intensity and quantum efficiency by incorporating just 2 wt% of MSMA‐modified silica into MEH‐PPV. However, hybrid A films did not show such enhancement of optoelectronic properties as the hybrid B films. The present study suggests the importance of the interface between the luminescent organic polymers and the inorganic silica on morphology and optoelectronic properties. Copyright © 2004 Society of Chemical Industry     

Colour Centres and Energy Transfer in BaF2-xClx:Eu2+ Phosphors

The optical absorption spectra of BaF2-xClx:Eu2 after ultraviolet (UV) light excitation were investigated.The differences between the absorption spectra after and before excitation (DAS) were observed.The DAS increase at both the high and the low energy side of F band in BaF2-xClx:Eu2 after 245 nm UV light excitation.The bleach effect of UV light and the absorption of electrons in the valence band may account for the former and the formation of Fa centres (association of F(Cl-) centres), whose absorption band matches the HeNe laser better, may explain the latter.In the write-in process, the transfer of electrons is via tunneling.In the readout process, the transfer of electrons captured in F(F-) and Fa centres is more likely via tunneling, and that of F(Cl-) centres is more likely via conduction band.     

数据包络分析模型及其应用研究

通过对传统的C^2R模型进行研究并加以改进，建立了C2RHZ模型,利用有色金属矿采选业1993-2001年科技创新的相关数据进行了计算分析。说明了C^2RHZ模型的应用价值．     

直流无刷电机驱动芯片LB11820M的原理及应用

LB11820M是日本SANYO(三洋)公司开发的三相直流无刷电机驱动芯片。它具备开环三相电机控制所需的全部有效功能，并且具有比较完善的保护电路。文中介绍了LB11820M的特点、功能和工作原理，给出了其典型应用电路。     

Synthesis of LiFePO4 with fine particle by co-precipitation method

LiFePO₄ is a potential candidate for the cathode material of the lithium secondary batteries. A co-precipitation method was adopted to prepare LiFePO₄ because it is simple and cheap. Nitrogen gas was needed to prevent oxidation of Fe²⁺ in the aqueous solution. The co-precipitated precursor shows the high reactivity with the reductive gas, and the single phase of LiFePO₄ is successfully synthesized with the aid of carbon under less reductive conditions. LiFePO₄ fine powder prepared by co-precipitation method shows high rate capability, impressive specific capacity and cycle property.     

Effects of gallia additions on sintering behavior of gadolinia-doped ceria

The effects of gallia additions on the sintering behavior of gadolinia-doped ceria were systematically investigated from the following aspects: the variation in sintered density, the variation in grain size, and the existing forms of Ga₂O₃ in CeO₂.Sintered density increased with increasing Ga₂O₃ content up to 5 mol.% and then it decreased with further addition of Ga₂O₃. Grain size also increased with increasing Ga₂O₃ content up to 5 mol.% and then decreased with further addition of Ga₂O₃. Decrease in grain size was caused by a pinning effect of Ga₂O₃ precipitation at grain boundaries. Lattice constant decreased with increasing Ga₂O₃ content up to 5 mol.%. This decrease will be due to the substitution of smaller Ga³⁺ ions for Ce⁴⁺ ions in the CeO₂ structure. According to the results obtained from scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses, the solubility limit of Ga₂O₃ in Ce_0.8Gd_0.2O_1.9 ceramics can be estimated to be nearly 5 mol.%. The addition of Ga₂O₃ up to the solubility limit was found to promote the sintering properties of Gd₂O₃-doped CeO₂.