An efficient in vitro plant regeneration system from leaves of Ophiorrhiza japonica Blume was established for the first time. Callus formation rate was more than 90.4 % from leaf segments on Murashige and Skoog (MS) supplemented with either α-naphthaleneacetic acid (NAA) alone or in combination with 6-benzyladenine (BA). The highest shoot regeneration (78.9 %) was achieved on MS medium containing 2.0 mg dm -3 BA and 0.2 mg dm -3 NAA, with an average of 9.4 shoots developed per leaf segment. Shoot regeneration was also improved when the leaf explants were cultured in MS basal medium supplemented with 0.5 % (m/v) polyvinylpyrrolidone (PVP). The leaf explants from seedlings with age of about 18 -27 d showed the highest shoot regeneration. The regenerated shoots were rooted on half-strength basal MS medium supplemented with 0.5 mg dm -3 indole-3-butyric acid (IBA), which averagely produced 24.8 roots per shoot. The plantlets were transferred to soil, where 100 % survived after 1 month of acclimatization.

To investigate whether shallow hinge joint fracture was caused by shear stress or flexural stress, during the demolition and reconstruction of Xiaojiang River bridge, two original girders were collected and shipped to the lab, and the shallow hinge joint between the two girders was rebuilt. Tests were performed to investigate the cracking load, failure mode, and force transmission performance of the hollow slab girder and shallow hinge joint under vehicle load. The test result shows that under eccentric load, when the load increases to 365 kN, the midspan bottom slab of the testing girder starts to fracture; as the load increases to 560 kN, the roof slab of the testing girder starts to fracture; the hinge joint has a maximum horizontal opening of 0.153 mm and vertical relative displacement of 0.201 mm; during the entire test loading process, the shallow hinge joint structure does not develop fracture and shear failure; and the shallow hinge structure demonstrates excellent shear stress transmission performance. In addition, based on hinge slab theory, the hinge joint internal force under vehicle load was calculated. Based on ACI 318-05 specification, CAN/CSA-S6-00, and JTG D61-2005, the hinge joint shear bearing capacity was calculated. Hinge joint stress resistances calculated from the three specifications all exceed the internal force. Among them, the calculation results from ACI 318-05 and CAN/CSA-S6-00 are similar, while the result from JTG D61-2005 specification significantly exceeds the internal force, which is mainly because the designed concrete direct shear strength fvd in the Chinese specification does not consider factors such as bonding surface coarseness, concrete pouring sequence, and material properties. Theoretical calculations and tests show that the actual failure mode of the shallow hinge joint in prefabricated hollow slab girder bridges is not caused by shear stress.

A review of terramechanics terrain models and discuss on their application in link-terrain, wheel-terrain and tire-terrain interaction are taken. Three kinds of pressure–sinkage relationship proposed by Bekker and Reece are studied. The loading and unloading is introduced in the model. And the relationship between the maximum shear stress and applied normal pressure is derived. The link tractive effort and drawbar pull at a given slip of an assumed shape and mass are deduced. Also the link moves in two dimensions. At last, the relationship of terrain sinkage vs. time, terrain pressure vs. sinkage and drawbar pull vs. slip for the link-terrain interface are simulated. The simulation is in good agreement with that got by Bekker.

JiaoJiang second bridge is a 5-span continuous cable-stayed bridge with double pylons and double cable planes whose main span is 480m. The main girder’s cross section has used a new type of composite beams --Semi-enclosed steel box composite girder, this article describes the design concept ofto this new type of composite girder, researched and analyzed the overall mechanical behavior of the composite girder, the spatial bearing behavior of the composite girder’s connecting piece, the segmental assembling technology of the composite girder and the mechanical behavior of its connecting piece by means of experiment and finite element calculation, then looks forward to the popularization and application prospect of this new type of composite girder.

The arm system of concrete pump truck is the most important because the rationality of the arm directly influences the performance and pouring position of the truck. For the arm system of the concrete pump truck, the movement of the arm system and the hydraulic cylinder are analyzed respectively with multi-body dynamic theory. By using numerical arithmetic to resolve the dynamic equation, the terminal track of the arms is analyzed. It shows that the kinetic equation built by multi-body dynamics can describe the dynamic characteristics of pump truck exactly.