阳离子化淀粉的结构分析与性能表征方法

介绍了红外光谱、1HNMR光谱、13C NMR光谱、空间排阻色谱-激光散射法、气相色谱、X-光散射、X-光衍射、显微镜等多种测试手段在阳离子化淀粉的官能团、取代度、区域选择性、相对分子质量、晶型和粒子形态等结构分析上的应用。并详细介绍了微分扫描热量测定和热重分析法在阳离子化淀粉溶胀温度、溶胀焓和热降解行为等性能表征上的应用。同时介绍了阳离子化淀粉应用性能表征的研究进展。     

Conformal Invariance and Noether Conserved Quantities of First-Order Lagrange Systems

In this paper the conformal invariance by infinitesimal transformations of first-order Lagrange systems is discussed in detail. The necessary and sufficient conditions of conformal invariance by the action of infinitesimal transformations being Lie symmetry simultaneously are given. Then we get the conserved quantities of conformal invariance by the infinitesimal transformations. Finally an example is given to illustrate the application of the results.     

STUDY OF DOPING EFFECT ON THE Bi2Sr2Ca2Cu3Oy SUPERCONDUCTOR

We have systematically investigated the doping effect on the Bi₂Sr₂Ca₂Cu₃O_y superconductive material. After entering into the crystal lattice, Pb and/or Sb atoms cause not only variations of the temperature condition during the sample preparation process, but also variations of structures and superconductivity. By analyzing the experimental results, we have come to the conclusion that the Pb and/or Sb atoms enter into the Bi-O planes, preferably occupy the sites of Bi ions, regulate the crystal structures and the distribution of oxygen ions in Bi-O planes and nearby lattice sites, thus benefiting the formation of the high-T_c phase and improving the superconductivity.     

海带碳点对斑马鱼胚胎发育的影响

以水产养殖常见的藻类海带为原料, 通过水热法绿色、便捷、高效地合成了生物质碳点, 全程实现了从原料选择到材料合成的绿色环保无污染。选择斑马鱼模式生物作为研究对象, 研究不同浓度碳点在斑马鱼胚胎发育过程中的荧光成像以及代谢情况。并通过研究碳点对斑马鱼胚胎发育的影响, 包括孵化率、心率和成鱼存活率等指标, 评价了制备的海带碳点的生物安全性。     

Upwind sail aerodynamics: A RANS numerical investigation validated with wind tunnel pressure measurements

The aerodynamics of a sailing yacht with different sail trims are presented, derived from simulations performed using computational fluid dynamics. A Reynolds-averaged Navier–Stokes approach was used to model sixteen sail trims first tested in a wind tunnel, where the pressure distributions on the sails were measured. An original approach was employed by using two successive simulations: the first one on a large domain to model the blockage due to the wind tunnel walls and the sails model, and a second one on a smaller domain to model the flow around the sails model. A verification and validation of the computed aerodynamic forces and pressure distributions was performed. The computed pressure distribution is shown to agree well with the measured pressures. The sail surface pressure was correlated with the increase of turbulent viscosity in the laminar separation bubble, the flow reattachment and the trailing edge separation. The drive force distribution on both sails showed that the fore part of the genoa (fore sail) provides the majority of the drive force and that the effect of the aft sail is mostly to produce an upwash effect on the genoa. An aerodynamic model based on potential flow theory and a viscous correction is proposed. This model, with one free parameter to be determined, is shown to fit the results better than the usual form drag and induced drag only, even if no friction drag is explicitly considered.     

Coulomb Explosion and Energy Loss of Energetic C20 Clusters in Dense Plasmas

The molecular dynamics （MD） method is used to simulate the interactions of energetic C20 clusters with the dense plasma targets within the framework of the linear Vlasov-Poisson theory. The influences of various clusters （H2, N2, C20 and C60 respectively） on stopping power are discussed. The simulation results show that the vicinage effects in the Coulomb explosion dynamics and the stopping power are strongly affected by the variations in the cluster speed and the plasma parameters. Coulomb explosions are found to proceed faster for higher speeds, lower plasma densities and higher electron temperatures. In addition, the cluster stopping power is strongly enhanced in the early stages of Coulomb explosions due to the vicinage effect, but this enhancement eventually diminishes, after the cluster constituent ions are sufficiently separated. For the large and heavy clusters, the stopping power ratio reaches much higher values in the early stage of Coulomb explosion owing to the constructive interferences in the vicinage effect.     

Conformal Invariance and Noether Conserved Quantities of First-Order Lagrange Systems

In this paper the conformal invariance by infinitesimal transformations of first-order Lagrange systems is discussed in detail. The necessary and sumeient conditions of conformal invariance by the action of infinitesimal transformations being Lie symmetry simultaneously are given. Then we get the conserved quantities of conformal invariance by the infinitesimal transformations. Finally an example is given to illustrate the application of the results.     

Analysis of hydrodynamic behaviors of multiple net cages in combined wave–current flow

Numerical simulation is performed to analyze the hydrodynamic response of a net cage and submerged mooring grid system exposed to waves and current. A series of experiments are conducted to validate the numerical model of net cage and grid mooring system. The numerical results of this model correspond with those obtained from experimental observations. Then, the numerical simulation of a multi-cage and mooring system under the action of waves combined with current is conducted. The influence of waves and current directions and the length of grid lines on the cage responses are discussed. The twin mooring system and the orthogonal mooring system are compared. Results show that for the orthogonal mooring system, the maximum tension force on the anchor line of the four-cage system is less than four times of that of the single-cage system, when both waves and current travel along the x-axis. The minimum net cage volume holding coefficient of the single-cage system is smaller than that of the four-cage system. The amplitude of the mooring line tension force for the twin mooring system is larger than the orthogonal mooring system.     

M_n~(k)(a_n,f,x)在L_p[0,1]中的逼近

本文引进了推广的Bernstein-Kantorvich多项式M_n~((k))(a_n,f,x)并且估计了它在空间L,[0,1]中的逼近阶。     

高效液相色谱串联质谱法同时测定水产品中24种性激素

建立了同时测定24种性激素的高效液相色谱串联质谱法,包括:睾酮、甲基睾酮、诺龙、苯丙酸诺龙、群勃龙、康力龙、勃地酮、雄烯二酮、美雄酮、炔诺酮、乙酸甲孕酮、乙酸甲羟孕酮、乙酸氯地孕酮、17α羟基孕酮、21α羟基孕酮、甲羟孕酮、左炔诺孕酮、雌酮、雌二醇、雌三醇、炔雌醇、己烷雌酚、己烯雌酚、双烯雌酚。乙酸乙酯提取2次,硅胶柱净化。采用甲醇、水作为流动相,经过CAPCELLPAK C18色谱柱分离后,采用APCI离子源,外标法定量。方法定量限为0.5～2μg/kg,加标回收率为80%～102%,相对标准偏差为6%～10%。方法实现了3类性激素的同时定量及确证分析。