M8891、3M4650精研机流球道改造

介绍N8891、3M4650精研机流球道改造。将原来钢板、钢筋焊接式结构改为胶木钢板组合式，避免钢球表面因与金属接触摩擦产生划伤，同时提高流球道定位精度，避免钢球与研磨盘沟槽棱边碰撞造成缺陷。

Expansion Plans for the Port of Durban： What Are the Issues for the City of Durban？

The Port of Durban is one of the largest ports in the Southern Hemisphere and is the main port for the Southern African region. However, the port is reaching its capacity limit and it is apparent that for South Africa＇s economic growth this port needs to expand. In order to expand the port needs to not only expand its waterside infrastructure but it would need to provide new logistics corridors though the city of Durban. The city of Durban has completely surrounded the port making expansion options difficult and intertwined with the planning of the city. This paper examines the various options and timelines for port expansion as well as the issues from the city perspective. Areas of possible conflict in this process revolve around traffic capacity and related road/rail infrastructure, environmental issues, social and economic impacts.

Tropical Pacific Decadal Variability in Subsurface Temperature

The nature decadal variability of the equatorial Pacific subsurface temperature is examined in the control simulation with the Geophysical Fluid Dynamics Laboratory coupled model CM2.1.The dominant mode of the subsurface temperature variations in the equator Pacific features a 20-40 year period and is North-South asymmetric about the equator.Decadal variations of the thermocline are most pronounced in the southwest of the Tropical Pacific.Decadal variation of the north-south asymmetric Sea Surface wind in the tropical Pacific,especially in the South Pacific Convergence,is the dominant mechanism of the nature decadal variation of the subsurface temperature in the equatorial Pacific.

Channel flow of the lower crust and its relation to large-scale tectonic geomorphology of the eastern Tibetan Plateau

The Tibetan Plateau is a large-scale tectonic geomorphologic unit formed by the interactions of plates.It has been commonly believed that convective removal of the thickened Tibetan lithosphere,or lateral flow of the lower crust beneath the Tibetan plateau plays a crucial role in the formation of the large-scale tectonic geomorphologic features.Recent geological and geo-physical observations have provided important evidence in support of the lower crustal channel flow model.However,it re-mains unclear as how the geometry of lower crustal channel and the lateral variation of crustal rheology within the lower crust channel may have affected spatio-temporal evolution of the tectonic geomorphologic unit of the Tibetan Plateau.Here,we use numerical methods to explore the mechanical relations between the lower crustal channel flow and the tectonic geomorpho-logic formation around the eastern Tibetan plateau,by deriving a series of governing equations from fluid mechanics theory.From numerous tests,our results show that the viscosity of the channeled lower crust is about(1-5)×1018 to(1-4)×1020 Pa s(Pa.s) beneath the margin of the eastern Tibetan Plateau,and increases to about 1022 Pa s beneath the Sichuan Basin and the southern region of Yunnan Province.Numerical tests also indicate that if channel flows of the lower crust exist,the horizontal propagation and the vertical uplifting rate of the eastern Tibetan Plateau margin could be accelerated with the time.Thus,the present results could be useful to constrain the rheological structure of the crust beneath the eastern Tibetan plateau,and to understand the possible mechanics of rapid uplift of the eastern Tibetan Plateau margin,especially since its occurrence at 8Ma as revealed by numerous geological observations.

Research on the transfers to Halo orbits from the view of invariant manifolds

This paper discusses the evolutions of invariant manifolds of Halo orbits by low-thrust and lunar gravity. The possibility of applying all these manifolds in designing low-thrust transfer, and the presence of single-impulse trajectories under lunar gravity are also explained. The relationship between invafiant manifolds and the altitude of the perigee is investigated using a Poincare map. Six types of single-impulse transfer trajectories are then attained from the geometry of the invariant manifolds. The evolutions of controlled manifolds are surveyed by the gradient law of Jacobi energy, and the following conclusions are drawn. First, the low thrust （acceleration or deceleration） near the libration point is very inefficient that the spacecraft free-flies along the invariant manifolds. The purpose is to increase its velocity and avoid stagnation near the libration point. Second, all con- trolled manifolds are captured because they lie inside the boundary of Eatlh＇s gravity trap in the configuration space. The evo- lutions of invariant manifolds under lunar gravity are indicated from the relationship between the lunar phasic angle and the altitude of the perigee. Third and last, most of the manifolds have preserved their topologies in the circular restricted three-body problem. However, the altitudes of the perigee of few manifolds are quite non-continuous, which can be used to generate single-impulse flyby trajectories.

VARIATIONAL PROPERTIES OF THE INTEGRATED MEAN CURVATURES OF TUBES IN SYMMETRIC SPACES

Let Pt denote the tubular hypersurface of radius t around a given compatible submanifold in a symmetric space of arbitrary rank. The authors will obtain some relations between the integrated mean curvatures of P, and their derivatives with respect to f. Moreover, the authors will emphasize the differences between the results obtained for rank one and arbitrary rank symmetric spaces.

The causal sequence investigation of the ring current ion-flux increasing and the magnetotail ion injection during a major storm

Comprehensive records are available in ENA data of ring current activity recorded by the NUADU instrument aboard TC-2 on 15 May, 2005 during a major magnetic storm （which incorporated a series of substorms）. Ion fluxes at 4-min temporal resolution derived from ENA data in the energy ranges 50-81 and 81-158 keV are compared with in situ particle fluxes measured by the LANL-SOPA instruments aboard LANL-01, LANL-02, LANL-97, and LANL-84 （a series of geostationary satellites that encircle the equatorial plane at -6.6 RE）. Also, magnetic fields measured simultaneously by the magetometers aboard GOES-10 and GOES-12 （which are also geostationary satellites） are compared with the particle data. It is demonstrated that ion fluxes in the ring current were enhanced during geomagnetic field tailward stretching in the growth phases of substorms rather than after Earthward directed dipolarization events. This observation, which challenges the existing concept that ring current particles are injected Earthward from the magnetotail following dipolarization events, requires further investigation using a large number of magnetic storm events.