29.5R25全钢工程机械子午线轮胎的研究与开发

介绍全钢工程机械子午线轮胎的设计特点和29.5R25无内胎全钢工程机械子午线轮胎的设计。结构设计:外直径1868mm,断面宽732mm,行驶面宽度630mm,胎圈着合直径628mm,花纹深度48mm。施工设计:胎面采用两方三块结构,胎体采用7×7×0.22+0.15HT钢丝帘线,带束层采用3+9+15×0.22+0.15HT钢丝帘线,胎体、带束层和钢丝圈的安全倍数均大于7,成型采用两鼓一次法成型机,硫化采用单模定型硫化机。成品轮胎试验结果表明,充气轮胎外缘尺寸和水压爆破试验结果符合标准要求。     

Polyaniline/carbon black composite as Pt electrocatalyst supports for methanol oxidation: Synthesis and characterization

Core/shell composites of polyaniline (PANI) and Vulcan XC‐72 Carbon (VC), in which the carbon represents the core and PANI forms the shell, were synthesized by in situ chemical oxidation polymerization. Platinum (Pt) particles were then deposited on the PANI/VC composites by chemical reduction method. The highest conductivity is obtained when a mass ratio of PANI/VC equals to 0.28, as proved by Fourier transform infrared spectra. And it is also proved that there are some reactions happened between PANI and VC. Scanning electron microscope, transmission electron microscope, and X‐ray diffraction measurements were performed to analyze their structure and surface morphology. It has been observed that the Pt particles are smaller in size and more uniformly distributed on these composite supports than on pure VC supports, considered as a reference. Methanol oxidation performed on the electrode modified by such a composite catalyst has been measured by cyclic voltammogram focusing on the attenuation of methanol oxidation current after 200 cycles. The attenuation degree for the composite catalyst is only one‐third of the one measured for a simple Pt/VC catalyst. It is proved that the composite catalyst better resist carbon monoxide poisoning in comparison with the Pt/VC catalyst, which may be due to the synergetic effects between the composite support and the Pt catalyst. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Thermoresponsive surface prepared by atom transfer radical polymerization directly from poly(vinylidene fluoride) for control of cell adhesion and detachment

Thermoresponsive surface was prepared from commercial poly(vinylidene fluoride) (PVDF) films via surface‐initiated atom transfer radical polymerization. The direct initiation of the secondary fluorinated site of PVDF facilitated grafting of the N‐isopropylacrylamide (NIPAAm) monomer. The PVDF surfaces grafted with poly(N‐isopropylacrylamide) [P(NIPAAm)] were characterized by X‐ray photoelectron spectroscopy. Kinetics study revealed that the P(NIPAAm) chain growth from the PVDF surface was consistent with a “controlled” process. The temperature‐dependent swelling behavior of the surfaces in aqueous solution was studied by atomic force microscope. At 37°C [above the lower critical solution temperature (LCST, about 32°C) of NIPAAm], the seeded cells adhered and spread on the NIPAAm grafted PVDF surface. Below the LCST, the cells detached from the P(NIPAAm)‐grafted PVDF surface spontaneously. The thermoresponsive surfaces are potentially useful as stimuli‐responsive adhesion modifiers in the biomedical fields.© 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

A simple method for identifying bubbling/jetting regimes transition from large submerged orifices using electrical capacitance tomography (ECT)

The bubbling–jetting transition regimes from large orifice submerged in water were investigated for various orifice diameters. A simple and fast way for identifying the regime transition was successfully developed using electrical capacitance tomography (ECT). In all the experiments deionised water was liquid phase and air was gas phase. Orifice gas velocity (V_N) and orifice diameter (d_o) were varied from 0.8 to 186 m/s and 4–21 mm, respectively. It was found that the V_N,trans. strongly depends on the orifice diameter. In the small orifice diameter (d_o < 10 mm), V_N,trans. greatly decreases with the increase of orifice diameter. However, in the large orifice diameter (d_o > 10 mm), the effect of orifice diameter on the transition velocity is insignificant. Finally, the data obtained by ECT compares with other works and the dimensionless orifice Reynolds number (Re_o ～11,000) is preferred to identify the bubbling–jetting transition regimes.     

电解铝液生产高品质6061铝合金圆铸锭工艺研究与实践

探讨了用电解铝液直接生产高品质6061铝合金圆铸锭工艺技术,主要在熔体处理、炉内精炼、晶粒细化、炉外在线净化、均匀化处理和生产设备等方面采取了相应的技术措施.结果表明,优化后的生产工艺制度能够满足高品质6061铝合金圆铸锭的质量要求,在均匀化过程中适宜的均匀化工艺为560℃×8h.     

Effect of graphite intercalation compounds in the interfacial zone on the mechanical and thermal properties of unidirectional carbon fiber reinforced spodumene composite

The interface in unidirectional carbon-fiber-reinforced β-spodumene matrix composite (UD-Cf/β-spodumene) significantly affected the thermal conductivity characteristics and mechanical properties due to the presence of a multi-layer interface. The mechanical and thermal properties of UD-Cf/β-spodumene composites with and without a multi-layer interface have been studied. The measured thermal conductivities, flexural strength and fracture toughness of composites with a multi-layer interface were much better than those composites with a clear interface. Interfacial layers with a multi-layer morphology originated from the diffusion of lithium from the β-spodumene matrix to the surface of the carbon fiber, which led to the formation of graphite intercalation compounds. The mechanical properties and thermal conductivity of UD-Cf/β-spodumene hot pressed at 1350 and 1400 °C were enhanced due to the textured interfacial microstructure and high thermal conductivity of graphite intercalation compounds. The textured interface decomposed at 1450 °C, resulting in the formation of a “strong” interface. Inevitably, the mechanical properties and thermal conductivity decreased.     

低游离甲醛脲醛树脂合成工艺研究

脲醛(UF)树脂是一种广泛应用于木材加工业的胶黏剂,文章采用碱-酸-碱合成工艺,探讨了甲醛与尿素的摩尔比、pH、反应温度及尿素加料方式等因素对UF树脂黏度及游离甲醛含量的影响,发展了制备低毒(游离甲醛含量0.13%)UF树脂的新工艺,并用IR对UF树脂进行了确证。     

A Chiral Salen-type Schiff Base Cu<Superscript>2+</Superscript> Complex for the Vinylic-type Polymerization of Norbornene

Abstract  

The chiral Salen-type Schiff base ligand H ₂ L (H ₂ L = (s)-(+)2,2′-bis(2-hydroxy-3-methoxybenzylideneamino)-1,1′-binaphthyl), was selected to obtain the new chiral Cu²⁺ complex CuL (1), which was found to catalyze the polymerization of norbornene (NBE). The complex shows the distinctively distorted geometry from a square-planar reactive center, this feature being suggested to account for the efficient catalysis on the vinylic-type polymerization of NBE, with moderate molecular weights and narrow molecular weight distributions.     

Enhancement of Polyunsaturated Fatty Acid Production by Selenium Treatment in Polyunsaturated Fatty Acid-Producing Fungus

The effect of selenium (Se) treatment on the content of intracellular polyunsaturated fatty acids (PUFA) was investigated. Selenium treatment could effectively increase the yields of arachidonic acid (AA) and linoleic acid (LA). When AA-producing Diasporangium jonesianum recombinant strain D-A1 was cultured in a medium containing 90 μg mL⁻¹ Se, the growth of D. jonesianum recombinant strain D-A1 was constrained, but the content of AA in the total fatty acids reached 9.3%, 1.7-fold higher than the control. The content of LA was also increased from 25.9 to 37.7%. Under various culture conditions, Se treatment (90 μg mL⁻¹) was generally beneficial to the yields of LA and AA. However, there was no significant increase in the contents of eicosapentaenoic acid (EPA) and γ-linolenic acid. Therefore, the use of Se is advantageous for regulating the content of intracellular PUFA in D. jonesianum recombinant strain D-A1, and could be good enhancer in the yields of AA and LA.     

双重密封坐便器的设计原理与特点

双重密封坐便器结构新颖独特,在系统中采用双重密封的方式,达到了既节约用水又保证密封效果的目的。通过详细介绍双重密封坐便器的设计原理与技术特色,并给出装配说明,阐述了其技术创新的意义。