Syntheses,Structures and Properties of Two New Coordination Polymers with Flexible Ligands as Linkers

Two new coordination polymers,[ZnL1]n（1,H2L1 = 5-（4-pyridyl）-methoxyl isophthalic acid） and[Ni（L2）2（H2O）4]n（2,HL2 = 4-（pyridin-4-ylmethoxy）benzolic acid）,have been synthesized and characterized by elemental analysis,PXRD,IR spectra,and single-crystal X-ray diffraction.Compound 1 has a three-dimensional framework constructed by 6-bridged L1^2- anions connecting the Zn2（O2C）4 paddlewheel-like units.Compound 2 contains a mononuclear molecular unit,and the central nickel atom adopts a slightly distorted octahedral geometry by two nitrogen atoms from different L2^- ligands and four oxygen atoms from water molecules.These molecular units link each other via four types of O-H…O hydrogen bonds to form an extended three-dimensional（3D） supramolecular network.The thermal and photoluminescent properties of 1 and 2 have also been investigated.

Dynamic modeling and simulation for the flexible spacecraft with dynamic stiffening

A rigid flexible coupling physical model which can represent a flexible spacecraft is investigated in this paper. By applying the mechanics theory in a non-inertial coordinate system,the rigid flexible coupling dynamic model with dynamic stiffening is established via the subsystemmodeling framework. It is clearly elucidated for the first time that,dynamic stiffening is produced by the coupling effect of the centrifugal inertial load distributed on the beamand the transverse vibration deformation of the beam. The modeling approach in this paper successfully avoids problems which are caused by other popular modeling methods nowadays： the derivation process is too complex by using only one dynamic principle; a clearly theoretical explanation for dynamic stiffening can＇t be provided. First,the continuous dynamic models of the flexible beamand the central rigid body are established via structural dynamics and angular momentumtheory respectively. Then,based on the conclusions of orthogonalization about the normal constrained modes,the finite dimensional dynamic model suitable for controller design is obtained. The numerical simulation validations showthat： dynamic stiffening is successfully incorporated into the dynamic characteristics of the first-order model established in this paper,which can indicate the dynamic responses of the rigid flexible coupling system with large overall motion accurately,and has a clear modeling mechanism,concise expressions and a good convergence.

Syntheses,Structures,and Properties of Three New Polymers Based on Flexible and Rigid Ligands

Three new supramolecular polymers, [（IP）（H2SO4）（H2O）]（1）, [（H2SDC）（BPA）]（2） and [Mn（SDC）（IP）2]n （3）, have been constructed by three modes（rigid IP, rigid SDC ＋ flexible BPA, rigid IP ＋ rigid SDC）. Polymers 1 and 2 are supramolecular structures, assembled by hydrogen bonds and π···π interactions. X-ray structure analysis of 3 shows waved 1D chains which form a 3D supramolecular network by hydrogen bonds and π···π interactions. Solid-state properties of thermal stability, luminescent properties, and X-ray powder diffractions for these crystalline materials have also been investigated, and polymer 3 is considered to be a good stable luminescence material.

THEORETICAL ANALYSIS OF COORDINATES MEASUREMENT BY FLEXIBLE 3D MEASURING SYSTEM

The system mathematical model of flexible 3D measuring system is built by theoretical analysis, and the theoretical formula for measuring space point coordinate is also derived. Frog-jumping based coordinate transform method is put forward in order to solve measuring problem for large size parts. The frog-jumping method is discussed, and the coordinate transform mathematical model is method of the space point coordinate compared to original value, and an advanced method is provided, Form the space point coordinate transform formula can derive the calculation measuring method for measuring large size parts.