28×9-15 14PR叉车轮胎的设计

介绍28×9-15 14PR叉车轮胎的设计。结构设计:外直径690 mm,断面宽228 mm,行驶面宽度210mm,行驶面弧度高0,胎圈着合直径387mm,胎圈着合宽度178mm,断面水平轴位置(H_1/H_2) 0. 942 3,花纹深度18 mm,花纹周节数24,花纹饱和度77%。施工设计:胎面采用两方三块结构,胎体采用4层1400dtex/3V_1和2层1400dtex/3V_2锦纶6浸胶帘布,缓冲层采用2层930dtex/2V_3锦纶6浸胶帘布,轮胎采用半芯轮式成型机成型、胶囊硫化机硫化。成品性能检测结果表明,轮胎的充气外缘尺寸和物理性能符合相关设计和国家标准要求。     

Anti-reflective nano- and micro-structures on 4H-SiC for photodiodes

In this study, nano-scale honeycomb-shaped structures with anti-reflection properties were successfully formed on SiC. The surface of 4H-SiC wafer after a conventional photolithography process was etched by inductively coupled plasma. We demonstrate that the reflection characteristic of the fabricated photodiodes has significantly reduced by 55% compared with the reference devices. As a result, the optical response I _illumination/I _dark of the 4H-SiC photodiodes were enhanced up to 178%, which can be ascribed primarily to the improved light trapping in the proposed nano-scale texturing.     

汽车涂膜质量的多重保证手段

介绍了汽车涂装车间涂装质量的保证手段,着重介绍了工艺参数管理、过程质量控制、现场材料质量监控和售后质量改进等。     

低变质粉煤热解过程研究

在管式电炉上研究了碱房沟、王家沟、孙家岔煤热解过程中温度变化对其热解产物收率和性能的影响。研究结果表明,管式炉电加热25 min温度达到500℃左右,热解气体大量析出,且随温度的升高,煤样失重率、煤气收率呈递增趋势,焦油收率基本不变;加热终温为800℃时,除CO外三种煤热解气体成分变化趋势基本一致,这和煤样的组织结构有关。     

Facile synthesis of an up-conversion luminescent and mesoporous Gd2O3 : Er3+@nSiO2@mSiO2 nanocomposite as a drug carrier

In this paper, we report the facile synthesis of a bifunctional inorganic nanocomposite which is composed of core-shell structured mesoporous silica coated with up-conversion Gd2O3?:?Er3+ particles. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 adsorption/desorption, and photoluminescence (PL) spectra were used to characterize the samples. The results indicate that the nanocomposite with general 50 nm shell thickness and 300 nm core size shows typical ordered mesoporous characteristics (2.3 nm) and has spherical morphology with smooth surface and narrow size distribution. The bifunctional system shows unique green up-conversion emission under 980 nm NIR laser excitation even after loading with drug molecules. In addition, biocompatibility tests on L929 fibroblast cells using an MTT assay reveals low cytotoxicity of the system. Drug release tests suggest that the nanocomposite has a controlled drug release property with ibuprofen (IBU) as the model drug. Interestingly, the up-conversion emission intensity of the bifunctional carrier increases with the released amount of model drug, thus allowing the release process to be monitored and tracked by the change of up-conversion luminescence intensity. This composite can potentially act as a functional drug carrier system.     

An analysis of CH4/N2 rich biogas production, fuel treatment process and microturbine application

Biogas usually contains CH₄ and CO₂ as main components with the ratio of 6: 4, and its composition varies with wide range depending on digester conditions. In addition to concentration change of each constituent, biogas composition could be changed due to the variations in the organic matter treatment process. The aim of the study is to analyze the production and application to a microturbine system of CH₄/N₂ rich biogas produced from Gong-Ju wastewater treatment plant. CH₄/N₂ rich biogas is produced due to the internal wastewater recirculation. The internal wastewater recirculation is intended to enhance NO₃ ^? removal without additional carbon source input. As a result, the digester was shown to be the highest contributor for nitrogen removal and average CH₄ concentration was lowered compared to the typical biogas composition. Nitrate removal rate was influenced by the internal recirculation ratio. Content of N₂ has no effect on biogas clean-up system performance. Besides, adaptability of CH₄/N₂ rich biogas to microturbine was satisfactory with very low NOx and SO₂ concentration in microturbine exhaust gas. Influence of high N₂ concentration of biogas on NOx concentration was limited due to the low combustion temperature.     

水热温度对SiC–C/C复合材料表面水热电泳沉积SiCn–MoSi2复合抗氧化涂层的影响

采用水热电泳沉积法在SiC–C/C复合材料表面制备了纳米碳化硅和二硅化钼的复相(SiCn–MoSi2)抗氧化涂层。采用X射线衍射和扫描电子显微镜等对制备涂层的晶相组成、表面及断面微观结构进行了表征。研究了水热温度对制备涂层的结构及高温抗氧化性能的影响,分析了涂层在1 600℃静态氧化行为及失效机理。结果表明:外涂层主要由MoSi2和β-SiC晶相组成。复相外涂层的致密程度、厚度及抗氧化性能随着水热温度的升高而提高。SiCn–MoSi2/SiC复合涂层具有较好的抗氧化和抗热震能力,在1 600℃氧化80 h后氧化质量损失为3.6×10–3 g/cm2。复合涂层在1 600℃的氧化失效主要是由于经过长时间氧化后SiO2玻璃膜层不能及时有效填补涂层中的缺陷,涂层中出现贯穿性的裂纹和孔洞导致的。     

Electrospinning-derived Tb2(WO4)3:Eu(3+) nanowires: energy transfer and tunable luminescence properties

One-dimensional Tb(2)(WO(4))(3) and Tb(2)(WO(4))(3):Eu(3+) nanowires have been prepared by a combination method of sol-gel process and electrospinning. X-Ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence (PL), low voltage cathodoluminescence (CL) and time-resolved emission spectra as well as kinetic decays were used to characterize the resulting samples. The as-obtained precursor samples present fiber-like morphology with uniform size, and Tb(2)(WO(4))(3) and Tb(2)(WO(4))(3):Eu(3+) nanowires were formed after annealing. Under ultraviolet excitation and low-voltage electron beams excitation into WO(4)(2-) and the f-f transition of Tb(3+), the Tb(2)(WO(4))(3) samples show the characteristic emission of Tb(3+) corresponding to (5)D(4)-(7)F(6, 5, 4, 3) transitions due to an efficient energy transfer from WO(4)(2-) to Tb(3+), while Tb(2)(WO(4))(3):Eu(3+) samples mainly exhibit the characteristic emission of Eu(3+) corresponding to (5)D(0)-(7)F(0, 1, 2) transitions due to an energy transfer occurs from WO(4)(2-) and Tb(3+) to Eu(3+). The increase of Eu(3+) concentration leads to the increase of the energy transfer efficiency from Tb(3+) to Eu(3+). The PL color of Tb(2)(WO(4))(3):x mol% Eu(3+) phosphors can be tuned from green to red easily by changing the doping concentration (x) of Eu(3+), making the materials have potential applications in fluorescent lamps and color display fields.     

纤维增强热塑树脂基复合材料界面问题

界面在高分子复合材料中占有很大比例,界面相互作用力的强弱决定着高分子复合材料的性能和应用,因此高分子复合材料的界面改性研究有着十分重要的意义。本文对树脂基复合材料中的结晶型热塑树脂复合材料界面和非结晶型热塑树脂复合材料界面问题进行了讨论和总结。     

Study of the preasphaltenes of coal liquefaction and its hydro-conversion kinetics catalyzed by SO4/ZrO2

The investigation of hydro-conversion behavior of the heavy intermediate products derived from coal direct liquefaction is advantageous to optimize the technological conditions of direct coal liquefaction and improve the oil yield. In this paper, the hydro-conversion of preasphaltenes catalyzed by SO₄²⁻/ZrO₂ solid acid was investigated based on the structural characterization of preasphaltenes and its hydro-conversion products, and the determination of products distribution and the kinetics of preasphaltenes hydro-conversion. The results indicated that the content of condensed aromatic rings increased, and the contents of hydrogen, oxygen and aliphatic side chains of preasphaltenes decreased with the increase of coal liquefaction temperature. The preasphaltenes showed higher hydro-conversion reactivity while SO₄²⁻/ZrO₂ solid acid was used as catalyst. Higher temperature and longer time were in favor of increasing the conversion and the oil + gas yield. The conversion of preasphaltenes hydro-conversion under 425 °C, for 40 min reached 81.3% with 51.2% oil + gas yield. SO₄²⁻/ZrO₂ solid acid was in favor of the catalytic cracking rather than the catalytic hydrogenation in the hydro-conversion of preasphaltenes. The activation energy of preasphaltenes conversion into asphaltenes was 72 kJ/mol. The regressive reactions were only observed at a higher temperature.