一类实奇芽等价的充要条件

给定一自反的Ｂａｎａｃｈ空间Ｘ．在ｃ^∞函数芽环∈（Ｘ）中,任何在原点Ｏ∈Ｘ的实奇芽ｆ,若其二阶Ｆｒｅｃｈｅｔ导数ｆ″（０）＝Ｔ是一个Ｆｒｅｄｈｏｌｍ算子,则它同构于形如：1/2+g(v)的一个芽．如果代替ｇ以一个与之同构的芽ｇ_１,显然得到一个与原来的芽同构的芽．然而,其逆是否真呢？本文将证明其逆命题亦真     

Investigating particle and volatile evolution during pulverized coal combustion using high-speed digital in-line holography

Devolatilization is an important process in pulverized coal combustion because it affects the ignition, volatile combustion, and subsequent char burning and ash formation. In this study, high-speed digital in-line holography is employed to visualize and quantify the particle and volatile evolution during pulverized coal combustion. China Shanxi bituminous coal particles sieved in the range of 105–154 µm are entrained into a flat flame burner through a central tube for the study. Time-resolved observations show the volatile ejection, accumulation, and detachment in the early stage of coal combustion. Three-dimensional imaging and automatic particle extraction algorithm allow for the size and velocity statistics of the particle and stringy volatile tail. The results demonstrate the smaller particle generation and coal particle swelling in the devolatilization. It is found that the coal particles and volatiles accelerate due to the thermal buoyancy and the volatiles move faster than the coal particles. On average, smaller particles move faster than the larger ones while some can move much slower possibly because of the fragmentation.     

四种藏药成方制剂中铅、砷含量的湿法消化-流动注射氢化物发生-原子吸收光谱法测定研究

选择藏族地区常用的四种藏药成方制剂安置精华散、当佐、仁青常觉和七十味珍珠丸作为研究对象,通过优化消化条件和测定条件,探索建立其铅、砷含量测定的湿法消化与流动注射氢化物发生-原子吸收光谱(FI-HAAS)联用分析方法,并对其铅砷含量进行精确测定。在优化的工作条件下,铅和砷的检出限分别为：0.067和0.012 μg·mL-1;定量限分别为：0.22和0.041 μg·mL-1;线性范围分别为：25～1 600 ng·mL-1(r=0.999 5),12.5～800 ng·mL-1(r=0.999 4);精密度(RSD)分别为：2.0%和3.2%;加标回收率范围分别为：98.00%～99.98%和96.67%～99.87%。四种藏药成方制剂的铅、砷含量测定结果如下,安置精华散中铅砷含量分别为：0.63～0.67和0.32～0.33 μg·g-1;当佐为：42.92～43.36和24.67～25.87 μg·g-1;仁青常觉为：1 611.39～1 631.36和926.76～956.52 μg·g-1;七十味珍珠丸为：1 102.28～1 119.27和509.96～516.87 μg·g-1。本研究建立了藏药成方制剂中铅、砷检测方法,并测定了四种藏药成方制剂中铅、砷含量,为其在临床安全有效使用提供了参考依据。     

CMOS-compatible light-emitting devices based on thin aluminum nitride film containing Al nanocrystals

Electroluminescence (EL) from Al-rich AlN thin films grown on p-type Si substrate by radio frequency (RF) magnetron sputtering has been observed at room temperature. The light-emitting structure based on the thin films can be driven by an electrical pulse as short as 10⁻⁵ s. No obvious change in the light emission intensity was observed after 10⁶ pulse cycles. It has been found that the light emission intensity increases with the Al concentration. It is shown that the phenomenon is due to the enhancement of the percolative conduction via the Al nanocrystals distributed in the AlN matrix as a result of the increase in Al concentration.     

沉积速率和氧分压对HfO2薄膜残余应力的影响

采用ZYGO MarkIII-GPI数字波面干涉仪对以K9玻璃为基底的电子束蒸发方法制备的HfO₂薄膜中的残余应力进行了研究,讨论了沉积速率、氧分压这两种工艺参量对HfO₂薄膜残余应力的影响.实验结果表明：在所有的工艺条件下,薄膜的残余应力均为张应力;随着沉积速率的升高,氧分压的减小,薄膜的堆积密度逐渐增大,而残余应力呈减小趋势.同时用X射线衍射技术测量分析了不同工艺条件下HfO₂薄膜的晶体结构,探讨了HfO₂薄膜晶体 关键词： 残余应力 2薄膜')" href="#">HfO₂薄膜 沉积速率 氧分压     

纳升电喷雾毛细管液相色谱-串联质谱鉴定K562细胞株中混合蛋白质

用标准蛋白质混合物建立了一种适用于低丰度混合蛋白质及其异构体分离与鉴定的蛋白质组学方法。通过IPG胶条等电聚焦分离蛋白质,染色后进行混合胶内酶切,采用纳升电喷雾毛细管液相色谱一串联质谱“散弹法（shot-gun）”分析酶切产物,并进行数据库检索鉴定蛋白质。运用该方法从K562细胞株样品中鉴定出14种具有重要功能的蛋白质,部分蛋白质同时在多个条带中出现,可能是异构体。肽段及其碎片离子的平均质量偏差小于0．05U,综合得分大都远远超过有效值。该方法灵敏、准确度高、分辨率高、省时、便于操椎存苍宗罾白甩异构体青而右优势．     

Efficient production of poly-gamma-glutamic acid by Bacillus subtilis ZJU-7

A strain with high poly-gamma-glutamic acid (gamma-PGA) production was isolated from fermented bean curd, a traditional Chinese food. The strain was named Bacillus subtilis ZJU-7 according to 16s rDNA sequencing and its taxonomic characters. The culture conditions for gamma-PGA production were evaluated. The most suitable carbon and nitrogen sources were sucrose and tryptone, respectively. Exogenous L-glutamic acid was necessary for gamma-PGA production, and the production of gamma-PGA increased on the addition of L-glutamic acid to the medium. In the medium containing 60 g/L of sucrose, 60 g/L of tryptone, 80 g/L of L-glutamic acid, and 10 g/L of NaCl, the yield of gamma-PGA reached 54.4 g/L after cultivation at 37 degrees C for 24 h, which was the highest gamma-PGA production compared with values reported in the literature. The average molecular mass of gamma-PGA produced was about 1.24 x 106 Daltons. B. subtilis ZJU-7 is genetically stable and can synthesize levan instead of gamma-PGA without the addition of L-glutamic acid to the medium.     

构元组集损伤断裂模型及其与内聚区模型的比较

结构的响应实质上是材料的响应,宏观结构损伤至断裂的发展过程也是材料性质不断演化的结果.构元组集模型从材料的微观物理变形机制出发,基于对泛函势理论和Cauchy-Born准则,抽象出两种构元:弹簧束构元和体积构元.在微观层次上,结构损伤和断裂的实质都是原子间键合力减弱和丧失的结果,而弹簧束构元是同一方向上的原子键的抽象,因此损伤可以通过弹簧束构元的响应曲线来反映.组集两种构元的响应,建立了材料的弹性损伤本构关系,从而能一致描述材料从弹性到损伤、破坏的发展过程.将构元组集模型的本构关系嵌入ABAQUS的用户材料单元子程序UMAT,实现对结构响应的数值模拟.论文模拟了包含中心预制裂纹三点弯曲梁的裂纹扩展过程,并与内聚区模型比较,给出了内聚区模型所假设的应力-位移关系曲线,并从材料损伤演化的角度对材料裂纹扩展过程做出了物理解释.     

幂指数小于2的无标度网络的性质

很多现实的复杂网络都具有无标度特性,其节点度具有幂律分布的规律。主要讨论幂指数γ<2的无标度网络的性质,指出当γ<2时,网络中最小度的节点数以及网络的平均度都与网络大小N有某种数量关系。通过与γ≥2的无标度网络对比,该类特殊网络呈现出不同的性质和行为,网络的边与节点相比呈现快速增长,具有更大的平均度,网络中有更多的边,网络不再稀疏。     

Modelling alkali metal emissions in large-eddy simulation of a preheated pulverised-coal turbulent jet flame using tabulated chemistry

The numerical modelling of alkali metal reacting dynamics in turbulent pulverised-coal combustion is discussed using tabulated sodium chemistry in large eddy simulation (LES). A lookup table is constructed from a detailed sodium chemistry mechanism including five sodium species, i.e. Na, NaO, NaO₂, NaOH and Na₂O₂H₂, and 24 elementary reactions. This sodium chemistry table contains four coordinates, i.e. the equivalence ratio, the mass fraction of the sodium element, the gas-phase temperature, and a progress variable. The table is first validated against the detailed sodium chemistry mechanism by zero-dimensional simulations. Then, LES of a turbulent pulverised-coal jet flame is performed and major coal-flame parameters compared against experiments. The chemical percolation devolatilisation (CPD) model and the partially stirred reactor (PaSR) model are employed to predict coal pyrolysis and gas-phase combustion, respectively. The response of the five sodium species in the pulverised-coal jet flame is subsequently examined. Finally, a systematic global sensitivity analysis of the sodium lookup table is performed and the accuracy of the proposed tabulated sodium chemistry approach has been calibrated.