稀土元素对钯室温电学性能的影响

研究了稀浓度(0.6at％以下)稀土元素(La、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Er、Yb)对钯的室温电学性能的影响。所有稀土元素均提高钯的电阻率(p)、降低电阻温度系数(α),实验结果与理论分析证明(p·α)_((?)d-RE)d=(p·α)_(Pd)。Gd以前的稀土元素降低钯的对铜热电势(ε),其余重稀土元素增大钯的对铜热电势。按0.1at％RE归一化处理的实验数据表明,轻稀土元素对钯电阻率的影响稍大于重稀土,但Ce、Eu、Yb呈反常影响,化合价和尺寸因素是影响电学性能的主要因素。     

企业文化需要追求个性创新发展

企业文化理论从20世纪80年代提出以来,经过20多年的实践,如今发展快、口号多、落地难,有的演变为企业文化的“作秀”。要提升企业核心竞争力,必须在塑造优秀企业文化中,追求企业个性,避免雷同,求得创新发展。     

粗粒料三轴试验橡皮膜嵌入量数值模拟

在粗粒料三轴试验中,橡皮膜嵌入量可造成显著的体积变形量测误差。本文针对颗粒材料的接触特点,利用Nagata Patch方法重建颗粒表面,基于重建曲面进行接触状态的判断和接触几何信息的计算,开发了高效的颗粒接触算法。该法采用dual mortar有限元方法处理颗粒与橡皮膜间的接触模拟,针对橡皮膜变形较大的特点,采用更新坐标的大变形计算格式,并根据重建的颗粒表面对颗粒-橡皮膜的距离进行几何修正,实现了颗粒-橡皮膜接触的精细化模拟,可较好地模拟计算“柔性”橡皮膜嵌入颗粒孔隙的过程。进行了Kramer钢球试验以及粗颗粒料和标准粗砂三轴试验橡皮膜嵌入过程的模拟计算,计算结果符合一般规律,与相应的试验结果吻合较好,验证了本文方法对于粗粒料膜嵌入问题的适用性。     

Isolation and Functional Characterization of a Salt-Responsive Calmodulin-Like Gene MpCML40 from Semi-Mangrove Millettia pinnata

Salt stress is a major increasing threat to global agriculture. Pongamia (Millettia pinnata), a semi-mangrove, is a good model to study the molecular mechanism of plant adaptation to the saline environment. Calcium signaling pathways play critical roles in the model plants such as Arabidopsis in responding to salt stress, but little is known about their function in Pongamia. Here, we have isolated and characterized a salt-responsive MpCML40, a calmodulin-like (CML) gene from Pongamia. MpCML40 protein has 140 amino acids and is homologous with Arabidopsis AtCML40. MpCML40 contains four EF-hand motifs and a bipartite NLS (Nuclear Localization Signal) and localizes both at the plasma membrane and in the nucleus. MpCML40 was highly induced after salt treatment, especially in Pongamia roots. Heterologous expression of MpCML40 in yeast cells improved their salt tolerance. The 35S::MpCML40 transgenic Arabidopsis highly enhanced seed germination rate and root length under salt and osmotic stresses. The transgenic plants had a higher level of proline and a lower level of MDA (malondialdehyde) under normal and stress conditions, which suggested that heterologous expression of MpCML40 contributed to proline accumulation to improve salt tolerance and protect plants from the ROS (reactive oxygen species) destructive effects. Furthermore, we did not observe any measurable discrepancies in the development and growth between the transgenic plants and wild-type plants under normal growth conditions. Our results suggest that MpCML40 is an important positive regulator in response to salt stress and of potential application in producing salt-tolerant crops.     

Hypoxia/Temperature/pH Triple Stimuli–Responsive Block Copolymers: Synthesis,Self-Assembly,and Controlled Drug Release

The amphiphilic block copolymer poly(methacrylic acid-co-2-nitroimidazole acrylate)-b-poly(2-(N,N-dimethylamino)ethyl methacrylate) (P(MAA-co-NIMA)-b-PDMAEMA) with the hypoxia/temperature/pH triple responsiveness is synthesized by reversible addition-fragmentation chain transfer polymerization (RAFT), hydrolysis, and 3-(3-dimethylaminopropyl)-1-ethylcarbodiimide (EDC) reactions, and successfully self-assembled into micelles. The hypoxia response in vitro is realized, and then the sensitivity of the self-assembled micelles to the hypoxia condition is studied by controlling the grafting amount of aminated 2-nitroimidazole. Because 2-(N,N-dimethylamino) ethyl methacrylate (DMAEMA) is a typical material sensitive to temperature and pH conditions, the self-assembled micelles are also responsive to temperature and different acidic/basic conditions. In addition, the cumulative release rate of doxorubicin (DOX) at 42 °C, pH = 6.0, and hypoxic conditions increases significantly, and verifies the synergistic promotion effect of the above stimulations. This intelligent polymer with triple response mechanism improves the controllability and efficiency of drug release, and is expected to be a drug carrier for cancer treatment.     

Room-Temperature Solid-State Lithium Metal Batteries Using Metal Organic Framework Composited Comb-Like Methoxy Poly(ethylene glycol) Acrylate Solid Polymer Electrolytes

Solid polymer electrolyte with good thermal stability and flexibility is an excellent candidate for solid-state lithium metal batteries, while its low ionic conductivity caused by high crystallinity limits its application at ambient temperature. Here a metal organic framework (zeolitic imidazolate framework-8, ZIF-8) composited comb-like methoxy poly(ethylene glycol) acrylate polymer electrolyte (MCPE) with high ionic conductivity (9.96 × 10⁻⁵ S cm⁻¹ at 30 °C) is prepared by an in situ UV polymerization method. The as-prepared MCPE exhibits improved mechanical property due to the introduction of porous ZIF-8 nanofillers, which is beneficial to suppress the growth of lithium dendrites. Consequently, the LiFePO₄||MCPE||Li cells show a high capacity of 116 mAh g⁻¹ at 30 °C and 0.5 C, and maintain 89.4% of initial capacity after 150 cycles with the average Coulombic efficiency of 99.9%. These results demonstrate that the MCPE shows great potential in solid-state lithium metal batteries near room temperature.     

等效岩体三维随机节理网络模型构建及其在两河口水电站中的应用

节理的存在对水电高陡岩质边坡的力学性质有重要影响,如何构建反映三维节理分布特征的等效岩体计算模型,是分析与评价岩体力学特性的关键。本文基于损伤力学和统计强度理论,在三维岩石破裂过程分析（RFPA3D）软件的基础上,提出了一种计算等效岩体三维随机节理网络模型的新方法。首先,基于Baecher模型和Monte-Carlo方法,在RFPA3D软件中实现了三维随机离散节理网络（Discrete fracture network,DFN）模型的重构。然后,利用RFPA3D软件内嵌DFN模型,赋予节理和岩石不同的力学参数,构建了工程尺度等效岩体三维随机节理网络模型,实现了三维随机节理岩体破裂过程、变形和强度等力学性质的分析。最后,以两河口水电站左岸边坡坝址区下游节理岩体为研究对象,验证了三维随机DFN模型的准确性,开展了研究区内节理岩体尺寸效应研究,并获得了研究区内岩体的表征单元体（Representative elementary volume,REV）和等效力学参数。该研究成果为等效岩体力学行为分析提供一种新方法。      

THEORETICAL INVESTIGATION ON BY-ONLY-CURRENT ELECTROMAGNETIC SEPARATION OF INCLUSION FROM MOLTEN METALS

The electromagnetic field under applied AC and DC current in round and rectangular pipe was systematically investigated, then a concept of "equivalent current density" was proposed for evaluating the inhomogeneous electromagnetic pinch force, and the mono-component removal efficiency and the overall removal efficiency of inclusion were formulated. It is founded that flat pipe is superior to round pipe for the electromagnetic removal of inclusion, and DC current can get a higher removal efficiency than A C current due to absence of skin phenomenon. Under usual condition, a removal efficiency of 52% for 10μm inclusion or more than 92% for 20μm inclusion can be achieved by imposing a current density of 3×106A/m2 in a flat pipe.     

陶瓷喷砂嘴的冲蚀磨损特性及其损坏机理

采用热压烧结工艺制备了Al2O3/TiC、Al2O3/(W,Ti)C和B4C陶瓷喷砂嘴.以SiC和Al2O3为冲蚀磨料进行了喷砂冲蚀试验.结果表明纯B4C陶瓷材料的烧结温度高、保温时间长、致密度低、晶粒粗,抗弯强度和断裂韧性低,但硬度最高;而Al2O3/TiC和Al2O3/(W,Ti)C陶瓷材料的烧结温度和保温时间比纯B4C陶瓷大大减小,致密度高,抗弯强度和断裂韧性比纯B4C陶瓷高1倍以上,但硬度相对低.对陶瓷喷砂嘴在磨料冲蚀下的应力状态进行了有限元分析,结果表明陶瓷喷嘴入口处所受的应力最大,出口次之,中间区域最小.B4C陶瓷喷砂嘴的最佳入口锥角为11°,而Al2O3/(W,Ti)C陶瓷喷砂嘴的最佳入口锥角为16°.陶瓷喷嘴入口和出口处的磨损机理主要表现脆性断裂;而中间区域的磨损机理主要表现为磨料颗粒对喷嘴内壁表面的研磨、抛光和微切削作用.     

用原料添加法提高钼粉粒度的探讨

叙述了在钼粉的工业化生产条件下采用原料添加法来提高最终粉末粒度，改善原料工艺性能的试验。研究表明：在钼酸铵原料中添加一定组份的钥粉，能有效地改善钼酸铵在动态焙解还原时的分散性和流动性，选择不同的添加量和添加粉粒度，可有效地把钼粉的ＦＳＳＳ粒度从２．５μｍ提高到４．２μｍ，从而可根据用粉要求，选择合适的添加工艺，来制取理想的钼粉。