地板辐射采暖地面散热量的简化计算方法

对加装了地板辐射采暖设施的空间采用三维稳态湍流模型,进行空气流动和传热特性的数值研究,并在与实验数据相比较的基础上,提出了一个便于实施计算的地板表面散热量的简化计算方法.提出的简化计算方法的思路即是对原计算公式中难以确定的房间内非加热表面的面积权重平均温度值Tp,用室温的修正量来代替.研究结果表明,数值结果和实验数据吻...     

Improved electrical and reliability characteristics in metal/oxide/nitride/oxide/silicon capacitors with blocking oxide layers formed under the radical oxidation process

We propose a Metal-Oxide-Nitride-Oxide-Silicon (MONOS) structure whose blocking oxide is formed by radical oxidation on the silicon nitride (Si3N4) layer to improve the electrical and reliability characteristics. We directly compare the electrical and reliability properties of the MONOS capacitors with two different blocking oxide (SiO2) layers, which are called a "radical oxide" grown by the radical oxidation and a "CVD oxide" deposited by chemical vapor deposition (CVD) respectively. The MONOS capacitor with a radical oxide shows a larger C-V memory window of 3.6 V at sweep voltages from 9 V to -9 V, faster program/erase speeds of 1 micros/1 ms at bias voltages of -6 V and 8 V, a lower leakage current of 7 pA and a longer data retention, compared to those of the MONOS capacitor with a CVD oxide. These improvements have been attributed to both high densification of blocking oxide film and increased nitride-related memory traps at the interface between the blocking oxide and Si3N4 layer by radical oxidation.     

Fe-C-Cr-V高铬堆焊合金的M7C3型碳化物及耐磨性

采用药芯焊丝埋弧堆焊方法制备含有0.9%~3.0%C,15%~20%Cr,2.0%~3.0%V的高铬合金.借助光学显微镜、扫描电镜和X射线衍射等手段,研究其显微组织及碳化物分布形貌.结果表明,其显微组织由马氏体+铁素体+奥氏体+初生M7C3+(Fe,Cr)3C+TiC等相组成.通过优化药芯焊丝组份及调整堆焊速度,获得了沿堆焊表面垂直方向定向分布的初生M7C3型碳化物,电子能谱分析显示该碳化物为(Fe,Cr,V)7C3.此外,考察了碳含量对高铬堆焊合金硬度及耐磨粒磨损性能的影响.表明其耐磨性优良,其中15~25μm M7C3型初生碳化物颗粒有效阻碍磨粒的显微切削运动,显著改善了耐磨性.     

A template-free alcoholthermal route to Ti(Sn)-doped ZnO nanorods

Ti(Sn)-doped single-crystalline ZnO nanorods with an average diameter of 20 nm and length up to nearly 1 μm were synthesized by a facile ultrasonic irradiation-assisted alcoholthermal method without involving any templates. Photoluminescence spectra of the Ti-doped ZnO nanorods were measured at room temperature and three emitting bands, being a violet emission at 400-415 nm, a blue band at 450-470 nm and a green band at around 550 nm, were detected. The emission intensities of the Ti-doped ZnO nanorods enhance gradually with increasing the doping concentrations. As to the Sn-doped ZnO nanorods, the green emission shifts to 540 nm and the emission intensities increase first but decrease later with increasing the doping concentrations.     

A facile synthesis of novel nanorod-assembling hollow nanowires of cadmium sulfide/DBTU nanocomposite

Novel nanorod-assembling hollow nanowires of cadmium sulfide/DBTU (N,N′-dibutylthiourea) nanocomposite were synthesized by reacting CdCl₂ with in situ produced H₂S from reaction of butylamine and carbon disulfide at molar ratio 3:3 of CS₂:BuNH₂ at 50 °C. This product was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SEAD), energy dispersive X-ray spectroscopy (EDAX), thermogravimetric (TG), Fourier transform infrared (FTIR) and UV-vis absorption spectra. A plausible mechanism that the extending DBTU molecules in solvent of CS₂ induce the formation of CdS/DBTU nanorods by coordinating with the formed CdS particles, and construct these nanorods to hollow nanowires via molecular interactions is proposed and discussed on the basis of experimental results. Photoluminescence (PL) of CdS/DBTU nanocomposite exhibits increasing emission intensity largely.     

Effect of Boron Precipitation Behavior on the Hot Ductility of Boron Containing Steel

The effect of boron (B) precipitation behavior on the hot ductility of B containing steel was investigated. Hot ductility of B containing steel was sensitive to the cooling rate (CR) in the range of 1 to 20 K/s (1 to 20 °C/s), whereas that of B-free steel showed little change with CR. Increased CR causes deepening and widening of the ductility trough in B containing steel. Particle tracking autoradiography (PTA) analysis and transmission electron microscope (TEM) image of the samples show that boron nitride (BN) particles form along prior austenite grain boundaries, and that as CR increases, these particles become smaller and more numerous. This increase in the number of small BN precipitates may promote intergranular fracture, leading to a decrease in hot ductility in the lower austenite temperature region (1173 to 1273 K (900 to 1000 °C)). Furthermore, the formation of filmlike ferrite at ~1123 K (850 °C) causes a decrease in the hot ductility of this steel regardless of B addition and CR.     

不同干燥方式对枣粉品质的影响

通过对变温压差膨化干燥、真空干燥、热风干燥和真空冷冻干燥4 种干燥方式所得枣粉的物理特性和营养成分的分析测定,研究不同干燥方式对枣粉品质的影响。结果表明：在物理特性方面：真空干燥和真空冷冻干燥枣粉呈现较好色泽,真空冷冻干燥枣粉溶解性差于其他3 种枣粉,吸湿性无明显差异,变温压差膨化干燥和热风干燥枣粉复水性较好,真空冷冻干燥枣粉的粒径和堆积密度最小;在营养成分方面：4 种枣粉的营养成分较鲜样均有不同程度的降低,变温压差膨化干燥和真空冷冻干燥枣粉的还原糖和总糖含量相对较高,真空干燥枣粉总酸含量最高,真空干燥和真空冷冻干燥枣粉的VC和黄酮含量较高,真空冷冻干燥和变温压差膨化干燥枣粉的环磷酸腺苷含量稍高于其他两种。枣粉的综合评分结果显示,真空冷冻干燥枣粉品质最佳,其次是真空干燥枣粉和变温压差膨化干燥枣粉,热风干燥枣粉品质最差。真空冷冻干燥和真空干燥生产成本高,变温压差膨化干燥枣粉品质较好,且所需干燥时间短,生产效率高、成本低,适宜在枣粉加工产业推广。     

声发射累计差量指标在采空区失稳预报中的应用

提出了评价地下工程稳定性的声发射事件率累计差量指标,该指标综合考虑一段时间内的声发射波动情况,能更准确地进行采场、采空区失稳预测。基于灰色理论建立声发射事件率累计差量指标的GM(1,1)预测模型,并应用于佛子冲铅锌矿104号矿体采空区失稳预报中,预测结果与实际情况具有良好的一致性。     

古交煤层气项目勘探开发现状及前景

根据区域地质构造、含煤地层、煤质及项目施工的煤层气钻井、生产试验井等方面的分析研究,总结了古交区块储层含气性、渗透性、生产数据等方面的成果,指出古交煤层气勘探目标和前景。     

石煤钒矿全湿法提钒技术中沉钒工艺研究

以钒反萃取液(主要成分五氧化二钒浓度99.30 g/L, 铁浓度3.15 g/L)为原料, 研究了钒反萃取液酸度、沉钒pH值、溶液电位等条件对沉钒率和产品五氧化二钒质量的影响。试验结果表明: 针对含铁较高的上述钒反萃取液, 为了获取优质五氧化二钒产品, 沉钒分二段进行。第一段沉钒是先用硫酸调整钒反萃液酸度为1.5 mol/L, 60 ℃水浴下加氯酸钠, 控制溶液电位为1 000 mV, 用15%的氨水调pH值在0.5以内, 90 ℃下搅拌1 h, 该段沉钒率为85%, 其产品五氧化二钒含量达99%以上, 铁含量在0.3%以下。第二段沉钒是将上述滤液接着用氨水调pH值至2.0并于90 ℃下搅拌1 h, 两段总沉钒率达99%, 第二段沉钒产品铁含量达1.5%, 需后处理, 经30%氢氧化钠溶液除铁后再次沉钒, 其产品五氧化二钒含量达99%以上, 铁含量在0.1%以下。