Dendritic side-branching with anisotropic viscous fingering

We studied dendritic side-branching mechanism in the experiment of anisotropic viscous fingering. We measured the time dependence of growth speed of side-branch and the envelop of side-branches. We found that the speed of side-branch gets to be faster than one of the stem and the growth exponent of the speed changes at a certain time. The envelope of side-branches is represented as Y ~ X^1.47.Comment: 8 pages, 8 figures, to submited in J. Crystal Growt

Heterogeneous Exits: Evidence from New Firms

This paper explores heterogeneous exits—bankruptcy, voluntary liquidation, and merger—by focusing on new firms. Using a sample of approximately 16,000 firms founded in Japan during 1997–2004, we examine the determinants of new-firm exit according to forms of exit. Regarding industry-specific characteristics, our findings indicate that new firms in capital-intensive and R&D-intensive industries are less likely to go bankrupt. In industries characterized by large amounts of capital and low price–cost margins, new firms are more likely to exit through voluntary liquidation and merger. Region-specific characteristics, such as regional agglomeration and unemployment rate, have significant effects on the hazards of exit, and their effects vary across different forms of exit. Moreover, we provide evidence that firm-specific characteristics, such as the number of employees, and entrepreneur-specific characteristics, such as educational background and age, play significantly different roles in determining each form of exit.New firm; exit; bankruptcy; voluntary liquidation; merger; competing risks proportional hazards model.

Binomial multiplicative model of critical fragmentation

We report the binomial multiplicative model for low impact energy fragmentation. Impact fragmentation experiments were performed for low impact energy region, and it was found that the weighted mean mass is scaled by the pseudo control parameter multiplicity. We revealed that the power of this scaling is a non-integer (fractal) value and has a multi-scaling property. This multi-scaling can be interpreted by a binomial multiplicative (simple biased cascade) model. Although the model cannot explain the power-law of fragment-mass cumulative distribution in fully fragmented states, it can produce the multi-scaling exponents that agree with experimental results well.Comment: 10 pages, 6 figures, A typo in Eq.(6b) was improved in Ver.

GaN HEMT DC I-V Device Model for Accurate RF Rectifier Simulation

Recently, various high-efficiency RF rectifiers have been proposed. In this article, to improve the simulation accuracy of RF active rectifier circuits, a new device model for GaN HEMTs is proposed that improves the reproducibility of ID-VDS characteristics in the third-quadrant region (both drain voltage and drain current are negative). Based on measured characteristic data of an actual GaN HEMT, the device parameters for this model have been decided, and the advantage of the new device model has been confirmed