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A chemoselective and diastereoselective synthesis of fused oxazolidines was achieved by a three-component cascade reaction of tetrahydroisoquinolines (THIQs), α,β-unsaturated aldehydes, and diethyl 2-oxomalonate. Probably due to the reactivity difference between the aldehyde and the ketone, the reaction proceeded through the condensation of THIQs with α,β-unsaturated aldehydes and 1,3-dipolar cycloaddition of the generated azomethine ylide intermediate with 2-oxomalonate. The key features are easily available starting materials, mild reaction conditions, broad substrate scope, and high chemo- and diastereoselectivity.

The calculation of sliding cable is difficult because it can dynamically pass through prescribed nodes and the length is variable. In order to solve the above problem, a calculation method based on tension distribution and temperature compensation for sliding cables was put forward. At first, the sliding cable was supposed to be fixed cable and the internal force of each cable segment was calculated. Then, the unbalanced tensions between neighboring cable segments were distributed to make the tensions equal. And then different temperatures were applied to the corresponding cable segments, which could cause temperature stress to compensate the unbalanced tensions between the initial calculated tensions and distributed tensions. At last the calculation was carried on again after applying the temperature to each cable segment. Moreover, an example was presented to verify the precision and validity of this method. The results show that the calculation method based on tension distribution and temperature compensation for sliding cables is effective.

The construction of stay cable is the key technology problem in large span spatial structures. This paper carried out a study on the construction scheme of stay cables based on the practical project of Shiyan stadium roof. The loss of tensile force caused by the seven steel wring with different construction order is summarized according to the experimental construction, and the tensile force slacken analysis method was used to calculate the stress of construction. Moreover, the loss of tensile force caused by anchor and relaxation is considered too. Then, the control tensile force of construction, which is used to realize the tensile construction one time, is obtained. Results of the engineering test show that the construction process is simplified and he construction scheme is economic under the condition of allowed precision. The method can provide reference for similar projects.

The tree-like structure is a branch of space bionic structures,belonging to the Bionic Architectural Structures. Cast-steel joints with branches are the keys to build the tree-like structures.They are used widely,and the most common joints in our projects are cast-steel joints with two、three and four branches. The cast-steel joints with two branches are planar,while the joints with three and four branches are spatial.Until now,the basic theoretical researches about the cast-steel joints with branches are also relatively scarce.This paper did researches about mechanical properties, calculation methods and structural optimization of the cast-steel joints with three branches deeply and systematically. The result shows that the bending moment has a big influence on the value of the max stress. And the three main failure modes of the cast-steel joint with three branches are yield of the main tubular along the axial direction, local buckling at the connection of the main tubular and branches, and the tearing out of the branches.

Basing on the practical engineering of elliptic paraboloid roof structural design in Qinyang Stadium, four structural schemes such as suspend-dome, single-layer latticed shell, double-layer latticed shell and rigid suspend-dome, are calculated and designed respectively. After satisfying the requirements of strength, stiffness and stability, the quantity of steel is compared. The advantages and disadvantages on mechanical performance, construction and cost of four schemes are discussed. Results of comparison provide the accordance for the final decision of structural schemes of Qinyang Stadium and can be referenced by other similar practical engineers.

In the title coordination polymer, {[Zn(C(9)H(7)NO(4))(C(10)H(14)N(4))]·2H(2)O}(n), the Zn(II) ion displays a distorted tetra-hedral geometry with two imidazole N atoms from two 1,1'-(butane-1,4-di-yl)bis-(imidazole) (bbi) ligands and two carboxyl-ate O atoms from two 2,6-dimethyl-pyridine-3,5-dicarboxyl-ate (dpdc) ligands. The bbi and dpdc ligands bridge the Zn(II) ions, forming layers parallel to (011). O-H⋯O and O-H⋯N hydrogen bonds and π-π inter-actions between the imidazole rings [centroid-centroid distance = 3.807 (5) Å] connect the layers. Two of the three uncoordinated water mol-ecules are disordered, each over two 0.25-occupancy positions.

In the title coordination polymer, {[Zn(C(9)H(7)NO(4))(C(10)H(14)N(4))]·2H(2)O}(n), the Zn(II) ion displays a distorted tetra-hedral geometry with two imidazole N atoms from two 1,1'-(butane-1,4-di-yl)bis-(imidazole) (bbi) ligands and two carboxyl-ate O atoms from two 2,6-dimethyl-pyridine-3,5-dicarboxyl-ate (dpdc) ligands. The bbi and dpdc ligands bridge the Zn(II) ions, forming layers parallel to (011). O-H⋯O and O-H⋯N hydrogen bonds and π-π inter-actions between the imidazole rings [centroid-centroid distance = 3.807 (5) A] connect the layers. Two of the three uncoordinated water mol-ecules are disordered, each over two 0.25-occupancy positions.