陶瓷材料疏水性能的研究进展

本文简述了疏水性表面的基本原理,分别从低表面能物质修饰和表面微细粗糙结构的构建两个方面,对疏水性陶瓷材料的制备技术和最新的成果进行了总结,介绍了其潜在的应用并对未来的研究方向作了展望.     

凝胶改性基底微藻细胞黏附特性及热力学分析

为强化微藻生物膜成膜过程中藻细胞与基底黏附,同时解决藻细胞残留造成的基底重复利用性差的问题,用聚N-异丙基丙烯酰胺(PNIPAAm)温缩型凝胶修饰基底.傅里叶红外光谱分析改性表面化学特性;结合微藻培养温度给出适宜藻细胞黏附的基底浸润特性;通过构建热力学模型,明晰温度对藻细胞与温缩型凝胶改性基底界面作用自由能的影响规律,...     

高拱坝表深孔碰撞泄洪消能水力特性

高拱坝坝身宣泄洪水产生高速水流,水流下泄时会对水垫塘底板产生极大的冲击压力.为保证下游冲刷安全,在有足够的深水垫消刹能量的同时,还需通过水舌在空中消耗部分能量.通过表深孔同轴碰撞的泄洪消能布置方式,研究不同表深孔流量比工况下水流特性及底板动水压强等水力特性.结果表明,表深孔上下水舌在空中碰撞、掺气,削弱射流的集中强度,...     

Dielectric Properties Investigation of Metal–Insulator–Metal (MIM) Capacitors

This study presents the construction and dielectric properties investigation of atomic-layer-deposition Al₂O₃/TiO₂/HfO₂ dielectric-film-based metal–insulator–metal (MIM) capacitors. The influence of the dielectric layer material and thickness on the performance of MIM capacitors are also systematically investigated. The morphology and surface roughness of dielectric films for different materials and thicknesses are analyzed via atomic force microscopy (AFM). Among them, the 25 nm Al₂O₃-based dielectric capacitor exhibits superior comprehensive electrical performance, including a high capacitance density of 7.89 fF·µm⁻², desirable breakdown voltage and leakage current of about 12 V and 1.4 × 10⁻¹⁰ A·cm⁻², and quadratic voltage coefficient of 303.6 ppm·V⁻². Simultaneously, the fabricated capacitor indicates desirable stability in terms of frequency and bias voltage (at 1 MHz), with the corresponding slight capacitance density variation of about 0.52 fF·µm⁻² and 0.25 fF·µm⁻². Furthermore, the mechanism of the variation in capacitance density and leakage current might be attributed to the Poole–Frenkel emission and charge-trapping effect of the high-k materials. All these results indicate potential applications in integrated passive devices.     

提高BEST110型摩托车齿轮精度的措施

对BEST110型摩托车发动机离合器齿轮通过毛坯热处理、机械加工、和最后的热处理等结合在一起来提高齿轮的精度,解决了发动机异响较大的问题并实现了国产化。     

Precise Quantification of Molybdate In Vitro by the FRET-Based Nanosensor ‘MolyProbe’

Molybdenum (Mo) is an essential trace element in all kingdoms of life. Mo is bioavailable as the oxyanion molybdate and gains biological activity in eukaryotes when bound to molybdopterin, forming the molybdenum cofactor. The imbalance of molybdate homeostasis results in growth deficiencies or toxic symptoms within plants, fungi and animals. Recently, fluorescence resonance energy transfer (FRET) methods have emerged, monitoring cellular and subcellular molybdate distribution dynamics using a genetically encoded molybdate-specific FRET nanosensor, named MolyProbe. Here, we show that the MolyProbe system is a fast and reliable in vitro assay for quantitative molybdate determination. We added a Strep-TagII affinity tag to the MolyProbe protein for quick and easy purification. This MolyProbe is highly stable, resistant to freezing and can be stored for several weeks at 4 °C. Furthermore, the molybdate sensitivity of the assay peaked at low nM levels. Additionally, The MolyProbe was applied in vitro for quantitative molybdate determination in cell extracts of the plant Arabidopsis thaliana, the fungus Neurospora crassa and the yeast Saccharomyces cerevisiae. Our results show the functionality of the Arabidopsis thaliana molybdate transporter MOT1.1 and indicate that FRET-based molybdate detection is an excellent tool for measuring bioavailable Mo.     

含油制冷剂在小管径换热管内流动沸腾换热关联式

通过对现有关联式预测值与6.34 mm和2.50 mm小管径换热管内实验数据的对比分析,发现其对6.34 mm换热管的适用性明显高于2.50 mm的换热管.相对而言,Zurcher修正的Kat-tan-Thome-Favrat模型对于6.34 mm换热管适用性最好,该关联式80%的预测值与实验数据点的偏差在±30%内.但对于2.50 mm的换热管只有40%数据点偏差在±30%内.根据实验结果,开发了适用于小管径换热管的基于局部油浓度和制冷剂-润滑油混合物性的两相换热增强因子模型,该模型能较好地反映润滑油在制冷剂中的实际存在状态及对制冷剂换热的影响规律,且物理意义明确,对于6.34 mm和2.50 mm的两种换热管,其预测值与90%以上的实验数据的偏差均在±20%以内.     

Mg-4Sn-1Ce合金的组织及热压缩行为

本文采用光学金相显微镜(OM)、X射线衍射(XRD)、扫描电镜(SEM)以及热压缩实验对Mg-4Sn-1Ce合金的微观组织和热压缩行为进行了研究。结果表明,铸态合金主要由"岛"状的α-Mg、Mg_2Sn、Ce_4Sn_5和MgSnCe相组成。合金在250～450℃和0.001～1s~(-1)应变速率下进行热压缩,热变形激活能Q为162.03 kJ/mol,本构方程为■=1.3×10~(12)·[sinh (0.019σ)]~(5.6)exp[-162030/(RT)]。热压缩温度由250℃升高到450℃,合金显微组织由(扁平状晶粒+挤压流线)组织演变为再结晶等轴晶粒组织。     

3种工况下多功能太阳能热泵的热泵制热水性能

简要介绍一种多功能太阳能热泵(MSAHP)系统的基本原理及其可实现的功能模式.对MSAHP样机在3种不同工况下热泵制热水性能进行了实验研究和对比分析,系统最高性能系数为6.1,在低温环境下性能系数范围也能达到1.8～5.9,表明MSAHP在热泵制热水模式下具有明显的节能效果.     

统计不相关最佳鉴别矢量集的本质研究

Until recently the hydrogen molecule structural parameters are calculated with the methods of quantum mechanics. To achieve results close to experimental values, the wave function used is complicated and has no clear physical meaning. Because the distribution of the electron probability density is a statistical rule, the macro-time has actually been used in the concept on a electron cloud graph. Here are obtained three formulas with a classical mechanics method on the bond-length re , bond-energy De and force constant k of the ground state hydrogen molecule, which have a clear physical meaning but no artificial parameters, and compared with experimental values, the relative errors are respectively less than 1% , 2% and 4% .