颞颌关节功能紊乱综合征的分类

关于颞颌关节功能紊乱综合征国内外报道较多,而对发病因素及治疗方法皆各抒已见。

Prediction of Instability Separation Modes and Its Application in Practical Dynamic Security Region

The transient critical boundary of dynamic security region (DSR) can be approximated by a few hyper planes correlated with instability separation modes. A method to fast predict instability separation modes is proposed for DSR calculation in power injection space. The method identifies coherent generation groups by the developed K-medoids algorithm, taking a similarity matrix derived from the reachability Grammian as the index. As an experimental result, reachability Grammian matrices under local injections are approximately invariant. It indicates that the generator coherency identifications are nearly consistent for different injections. Then instability separation modes can be predicted at the normal operating point, while average initial acceleration is considered as the measure of the critical generator group to amend the error. Moreover, based on these predicted instability separation modes, a critical point search strategy for DSR calculation is illustrated in the reduced injection space of the critical generators. The proposed method was evaluated using New England Test System, and the computation accuracy and speed in determining the practical DSR were improved.

Marine Accident Analysis with GIS

In this study, marine casualties which are recorded Global Integrated Shipping Information System （GISIS） in 2007-2011, result in death, injury, economic loss and environmental pollution are discussed. The studied types of ships are container, bulk dry, general cargo, roro, ropax, passenger and tankers. The information contained in GISIS system is textual format and it is difficult to systematically analyze this information. For this reason, by creating a new data base, which is Microsoft Excel-based, ship accidents are classified according to name, flag state and type of ship, type, size and coordinates of the accidents that are evaluated by entering the Geographical Information System（GIS）. In the study, all marine areas having been separated into ranges in ArcGIS 10 program, the marine areas with intensive marine accidents have been determined and marine accident chart has been created. As a result of the study, high risk marine areas are Strait of Dover and Hamburg in the North Europe, Belfast Shores in Ireland, the seas surrounding Great Belt, Kattegat and Copenhagen in Baltic Sea, In far east, Kanmon Strait, Urage Channel and Bungo Strait in Japan, Shanghai, Ningbo and Hong Kong in China.

Philosophy of Science and Post-theoretical Life-World

Philosophy of science has arisen as alternative to epistemology, because scientific development wanted another kind of explanation than traditional epistemological one. The latter kind of explanation is theoretically loaded and based on latent ontological assumptions. Epistemology offers science a ＂road map＂ for researcher＇s thinking. Thus epistemology knows what science should be, and philosophy of science take science for granted--existing as an empirical fact. Philosophy of science had always been a reflective and critical discipline that didn＇t want any a-priory knowledge. The main distinction between these fields of knowledge is as follows： epistemology is theoretical and projective kind of knowledge whereas philosophy of science is a non-theoretical, or better, a ＂post-theoretical＂ discipline. All facts and statements arising from philosophy of science lie within the heterogeneous space, where there is continuous transit of pre-theoretical, theoretical and post-theoretical versions of knowledge. The inevitability of conservation and utilization of human thought products is recognized, which is supplemented by the need to study the impact of theoretical thinking upon social practices.

A simple method to design non-collision relative orbits for close spacecraft formation flying

A set of linearized relative motion equations of spacecraft flying on unperturbed elliptical orbits are specialized for particular cases, where the leader orbit is circular or equatorial. Based on these extended equations, we are able to analyze the relative motion regulation between a pair of spacecraft flying on arbitrary unperturbed orbits with the same semi-major axis in close formation. Given the initial orbital elements of the leader, this paper presents a simple way to design initial relative orbital elements of close spacecraft with the same semi-major axis, thus preventing collision under non-perturbed conditions. Considering the mean influence of J_2 perturbation, namely secular J_2 perturbation, we derive the mean derivatives of orbital element differences, and then expand them to first order. Thus the first order expansion of orbital element differences can be added to the relative motion equations for further analysis. For a pair of spacecraft that will never collide under non-perturbed situations, we present a simple method to determine whether a collision will occur when J_2 perturbation is considered. Examples are given to prove the validity of the extended relative motion equations and to illustrate how the methods presented can be used. The simple method for designing initial relative orbital elements proposed here could be helpful to the preliminary design of the relative orbital elements between spacecraft in a close formation, when collision avoidance is necessary.