Jensen’s Inequality for Backward Stochastic Differential Equations

Abstract Under the Lipschitz assumption and square integrable assumption on g, the author proves that Jensen’s inequality holds for backward stochastic differential equations with generator g if and only if g is independent of y, g(t, 0) ≡ 0 and g is super homogeneous with respect to z. This result generalizes the known results on Jensen’s inequality for g- expectation in [4, 7–9]. *Project supported by the National Natural Science Foundation of China (No.10325101) and the Science Foundation of China University of Mining and Technology.     

An implicit method for linear ill‐posed problems with perturbed operators

An implicit iterative method is applied to solving linear ill‐posed problems with perturbed operators. It is proved that the optimal convergence rate can be obtained after choosing suitable number of iterations. A generalized Morozov's discrepancy principle is proposed for the problems, and then the optimal convergence rate can also be obtained by an a posteriori strategy. The convergence results show that the algorithm is a robust regularization method. Copyright © 2006 John Wiley & Sons, Ltd.     

Laser-induced site-selective silver seeding on polyimide for electroless copper plating

Ag particles were generated on Ag⁺-doped polyimide film by laser direct writing, followed by selective copper deposition using the metallic silver particles as seeds. Laser irradiation caused in situ reduction and agglomeration of silver on the polyimide film. The copper lines were less uniform and compact with higher scanning velocity and the width of the deposited copper line could reach 25 μm. Equations of the relationship between scanning velocity and connectivity of the deposited copper patterns have been derived. The process was characterised by AFM, XPS, SEM, and semiconductor characterisation system.     

Spin-transfer switching in MgO magnetic tunnel junction nanostructures

Spin-transfer driven switching was observed in MgO based magnetic tunnelling junctions (MTJ) with tunnelling magnetoresistance ratio of up to 160% and the average intrinsic switching current density (J_c0) down to 2 MA/cm², which are the best known results reported in spin-transfer switched MTJ nanostructures. Based on a comparison of results both from MgO and AlO_x MTJs, further switching current decrease via MgO dual structures with two pinned layers is discussed.     

Electrical and magnetic properties of CoFeAlO thin films

Influences of oxygen-partial pressure and annealing on the electrical and magnetic properties of CoFeAlO thin films were systematically investigated by means of resistivity, permeability, magnetization and ferromagnetic resonance (FMR) measurements. It was found that, with increasing oxygen-partial pressure or under annealing, the electrical resistivity of the film increased and the magnetic softness decreased, which is attributed to the microstructural change of the film. Interestingly, an as-deposited Co_45.30Fe_20.65Al_19.34O_14.71 film was found to exhibit an inverted hysteresis loop with negative coercivity, and this peculiar phenomenon disappeared upon effects of oxygen-partial pressure and annealing. It was also found that the as-deposited films owned a narrow FMR line width that increased with increasing oxygen-partial pressure or under annealing.     

Kuhn-Tucker条件与线性规划的对偶性

证明了线性规划的K uhn-Tucker条件蕴含着它的对偶问题,解释了L agrange乘子的意义.进而显示了K-T条件中的互补松驰性与对偶线性规划的互补松紧定理之间的联系.     

Formation of functional groups on graphite during oxygen plasma treatment

Improved sample wettability was obtained by oxygen plasma functionalization of pyrolytic graphite. The samples were exposed to highly dissociated oxygen plasma with the density of 1 × 10¹⁶ m⁻³, the electron temperature of about 5.5 eV and the density of neutral oxygen atoms of 8 × 10²¹ m⁻³ for 20 s. The surface wettability was measured by a contact angle of water drop. The contact angle dropped from original 112° down to about 1°. The functional groups were detected by XPS analyses. The survey spectrum showed a substantial increase of oxygen concentration on the surface, while high-resolution analyses showed additional oxygen was bonded onto the graphite surface in the form of C-O polar functional group responsible for the increase of the surface energy.     

Application of Electron-Shelving Detection via 423 nm Transition in Calcium-Beam Optical Frequency Standard

A new scheme of small compact optical frequency standard based on thermal calcium beam with application of 423 nm shelving detection and sharp-angle velocity selection detection is proposed. Combining these presented techniques, we conclude that a small compact optical frequency standard based on thermal calcium beam will outperform the commercial caesium-beam microwave dock, like the 5071 Cs clock （from Hp to Agilent, now Symmetricom company）, both in accuracy and stability.     

Two New Eremophilenolides from Ligularia muliensis

Many Ligularia species have long been used as traditional folk medicine for theirantibiotic, antiphlogistic and antitussive activities1, and were found to be an importantsource of eremophilane. In the course of our search for bioactive sesquiterpenoids, w…     

Frequency Selectivity Behaviour in the Auditory Midbrain： Implications of Model Study

By numerical simulations on frequency dependence of the spiking threshold, i.e. on the critical amplitude of periodic stimulus, for a neuron to fire, we find that bushy cells in the cochlear nuclear exhibit frequency selec- tivity behaviour. However, the selective frequency band of a bushy cell is far away from that of the preferred spectral range in human and mammal auditory perception. The mechanism underlying this neural activity is also discussed. Further studies show that the ion channel densities have little impact on the selective frequency band of bushy cells. These findings suggest that the neuronal behaviour of frequency selectivity in bushy cells at both the single cell and population levels may be not functionally relevant to frequency discrimination. Our results may reveal a neural hint to the reconsideration on the busily cell functional role in auditory information processing of sound frequency.