Awaking the Sleeping Dragon: The Evolving Chinese Patent Laws and its Implications for Pharmeceutical Patents

Part I of this Comment will discuss the development of the Chinese IP system and discuss why it has been ineffective in protecting pharmaceutical patents by comparing it to the US patent system. Part II analyzes the third amendment to the Chinese patent law and how it protects patents, particularly pharmaceutical ones, and deters counterfeiters from infringing upon the patents. Part II also presents different views on the effectiveness of the third amendment to protect patents. Part III argues that even though the third amendment is a great leap forward, pharmaceutical counterfeiting will continue to happen if the local governments do not cooperate with the central government in enforcing patent protection laws

Swimming of a Waving Plate

The purpose of this paper is to study the basic principle of fish propulsion. As a simplified model, the two-dimensional potential flow over a waving plate of finite chord is treated. The solid plate, assumed to be flexible and thin, is capable of performing the motion which consists of a progressing wave of given wave length and phase velocity along the chord, the envelope of the wave train being an arbitrary function of the distance from the leading edge. The problem is solved by applying the general theory for oscillating deformable airfoils. The thrust, power required, and the energy imparted to the wake are calculated, and the propulsive efficiency is also evaluated. As a numerical example, the waving motion with linearly varying amplitude is carried out in detail. Finally, the basic mechanism of swimming is elucidated by applying the principle of action and reaction

On the finiteness of the classifying space for the family of virtually cyclic subgroups

Given a group G, we consider its classifying space for the family of virtually cyclic subgroups. We show for many groups, including for example, one-relator groups, acylindrically hyperbolic groups, 3-manifold groups and CAT(0) cube groups, that they do not admit a finite model for this classifying space unless they are virtually cyclic. This settles a conjecture due to Juan-Pineda and Leary for these classes of groups

Hydromechanics of swimming propulsion. part 1. Swimming of a two-dimensional flexible plate at variable forward speeds in an inviscid fluid

The most effective movements of swimming aquatic animals of almost all sizes appear to have the form of a transverse wave progressing along the body from head to tail. The main features of this undulatory mode of propulsion are discussed for the case of large Reynolds number, based on the principle of energy conservation. The general problem of a two-dimensional flexible plate, swimming at arbitrary, unsteady forward speeds, is solved by applying the linearized inviscid flow theory. The large-time asymptotic behaviour of an initial-value harmonic motion shows the decay of the transient terms. For a flexible plate starting with a constant acceleration from at rest, the small-time solution is evaluated and the initial optimum shape is determined for the maximum thrust under conditions of fixed power and negligible body recoil

Generation of upstream advancing solitons by moving disturbances

This study investigates the recently identified phenomenon whereby a forcing disturbance moving steadily with a transcritical velocity in shallow water can generate, periodically, a succession of solitary waves, advancing upstream of the disturbance in procession, while a train of weakly nonlinear and weakly dispersive waves develops downstream of a region of depressed water surface trailing just behind the disturbance. This phenomenon was numerically discovered by Wu & Wu (1982) based on the generalized Boussinesq model for describing two-dimensional long waves generated by moving surface pressure or topography. In a joint theoretical and experimental study, Lee (1985) found a broad agreement between the experiment and two theoretical models, the generalized Boussinesq and the forced Korteweg de Vries (fKdV) equations, both containing forcing functions. The fKdV model is applied in the present study to explore the basic mechanism underlying the phenomenon. To facilitate the analysis of the stability of solutions of the initial-boundary-value problem of the fKdV equation, a family of forced steady solitary waves is found. Any such solution, if once established, will remain permanent in form in accordance with the uniqueness theorem shown here. One of the simplest of the stationary solutions, which is a one-parameter family and can be scaled into a universal similarity form, is chosen for stability calculations. As a test of the computer code, the initially established stationary solution is found to be numerically permanent in form with fractional uncertainties of less than 2% after the wave has traversed, under forcing, the distance of 600 water depths. The other numerical results show that when the wave is initially so disturbed as to have to rise from the rest state, which is taken as the initial value, the same phenomenon of the generation of upstream-advancing solitons is found to appear, with a definite time period of generation. The result for this similarity family shows that the period of generation, T[sub]S, and the scaled amplitude [alpha] of the solitons so generated are related by the formula T[sub]S = const [alpha]^-3/2. This relation is further found to be in good agreement with the first-principle prediction derived here based on mass, momentum and energy considerations of the fKdV equation

Water waves generated by the translatory and oscillatory surface disturbance

The problem under consideration is that of two-dimensional gravity waves in water generated by a surface disturbance which oscillates with frequency Ω/2π and moves with constant rectilinear velocity U over the free water surface. The present treatment may be regarded as a generalization of a previous paper by De Prima and Wu (Ref. 1) who treated the surface waves due to a disturbance which has only the rectilinear motion. It was pointed out in Ref. 1 that the dispersive effect, not the viscous effect, plays the significant role in producing the final stationary wave configuration, and the detailed dispersion phenomenon clearly exhibits itself through the formulation of a corresponding initial value problem. Following this viewpoint, the present problem is again formulated first as an initial value problem in which the surface disturbance starts to act at a certain time instant and maintains the prescribed motion thereafter. If at any finite time instant the boundary condition is imposed that the resulting disturbance vanishes at infinite distance (because of the finite wave velocity), then the limiting solution, with the time oscillating term factored out, is mathematically determinate as the time tends to infinity and also automatically has the desired physical properties. From the associated physical constants of this problem, namely Ω, U, and the gravity constant g, a nondimensional parameter of importance is found to be a = 4ΩU/g. The asymptotic solution for large time shows that the space distribution of the wave trains are different for 0 1. For 0 1, two of these waves are suppressed, leaving two waves in the downstream. At a = 1, a kind of "resonance" phenomenon results in which the amplitude and the extent in space of one particular wave both increase with time at a rate proportional to t^(1/2). Two other special cases: (1) Ω → 0 and U > 0, (2) U = 0, Ω > 0 are also discussed; in these cases the solution reduces to known results

A wake model for free-streamline flow theory. Part 1. Fully and partially developed wake flows and cavity flows past an oblique flat plate

A wake model for the free-streamline theory is proposed to treat the two-dimensional flow past an obstacle with a wake or cavity formation. In this model the wake flow is approximately described in the large by an equivalent potential flow such that along the wake boundary the pressure first assumes a prescribed constant under-pressure in a region downstream of the separation points (called the near-wake) and then increases continuously from this under-pressure to the given free-stream value in an infinite wake strip of finite width (the far-wake). Application of this wake model provides a rather smooth continuous transition of the hydrodynamic forces from the fully developed wake flow to the fully wetted flow as the wake disappears. When applied to the wake flow past an inclined flat plate, this model yields the exact solution in a closed form for the whole range of the wake under-pressure coefficient

Hydromechanics of swimming propulsion. Part 2. Some optimum shape problems

The optimum shape problems considered in this part are for those profiles of a two-dimensional flexible plate in time-harmonic motion that will minimize the energy loss under the condition of fixed thrust and possibly also under other isoperimetric constraints. First, the optimum movement of a rigid plate is completely determined; it is necessary first to reduce the original singular quadratic form representing the energy loss to a regular one of a lower order, which is then tractable by usual variational methods. A favourable range of the reduced frequency is found in which the thrust contribution coming from the leading-edge suction is as small as possible under the prescribed conditions, outside of which this contribution becomes so large as to be hard to realize in practice without stalling. This optimum solution is compared with the recent theory of Lighthill (1970); these independently arrived-at conclusions are found to be virtually in agreement. The present theory is further applied t0 predict the movement of a porpoise tail of large aspect-ratio and is found in satisfactory agreement with the experimental measurements. A qualitative discussion of the wing movement in flapping flight of birds is also given on the basis of optimum efficiency. The optimum shape of a flexible plate is analysed for the most general case of infinite degrees of freedom. It is shown that the solution can be determined to a certain extent, but the exact shape is not always uniquely determinate