Structural Synthesis of Compliant Metamorphic Mechanisms Based on Adjacency Matrix Operations

A compliant metamorphic mechanism attributes to a new type of metamorphic mechanisms evolved from rigid metamorphic mechanisms. The structural characteristics and representations of a compliant metamorphic mechanism are different from its rigid counterparts, so does the structural synthesis method. In order to carry out its structural synthesis, a constraint graph representation for topological structure of compliant metamorphic mechanisms is introduced, which can not only represent the structure of a compliant metamorphic mechanism, but also describe the characteristics of its links and kinematic pairs. An adjacency matrix representation of the link relationships in a compliant metamorphic mechanism is presented according to the constraint graph. Then, a method for structural synthesis of compliant metamorphic mechanisms is proposed based on the adjacency matrix operations. The operation rules and the operation procedures of adjacency matrices are described through synthesis of the initial configurations composed of s＋1 links from an s-link mechanism （the final configuration）. The method is demonstrated by synthesizing all the possible four-link compliant metamorphic mechanisms that can transform into a three-link mechanism through combining two of its links. Sixty-five adjacency matrices are obtained in the synthesis, each of which corresponds to a compliant metamorphic mechanism having four links. Therefore, the effectiveness of the method is validated by a specific compliant metamorphic mechanism corresponding to one of the sixty-five adjacency matrices. The structural synthesis method is put into practice as a fully compliant metamorphic hand is presented based on the synthesis results. The synthesis method has the advantages of simple operation rules, clear geometric meanings, ease of programming with matrix operation, and provides an effective method for structural synthesis of compliant metamorphic mechanisms and can be used in the design of new compliant metamorphic mechanisms.

Adding Sub-chain Method for Structural Synthesis of Planar Closed Kinematic Chains

For at least the past five decades,structural synthesis has been used as a main means of finding better mechanisms with some predefined function.In structural synthesis,isomorphism identification is still a problem unsolved well,and to solve this problem is very significant to the design of new mechanisms.According to the given degree of freedom（DOF） and link connection property of planar closed chain mechanisms,vertex assortment is obtained.For solving the isomorphism problem,a method of the adding sub-chains is proposed with the detailed steps and algorithms in the synthesizing process.Employing this method,the identification code and formation code of every topological structure are achieved,therefore many isomorphic structures could be eliminated in time during structural synthesis by comparing those codes among different topological graphs,resulting in the improvement of synthesizing efficiency and accuracy,and the approach for eliminating rigid sub-chains in and after the synthesizing process is also presented.Some examples are given,including how to add sub-chains,how to detect simple rigid sub-chains and how to obtain identification codes and formulation codes et al.Using the adding sub-chain method,the relative information of some common topological graphs is given in the form of table.The comparison result is coincident with many literatures,so the correctness of the adding sub-chain method is convinced.This method will greatly improve the synthesizing efficiency and accuracy,and has a good potential for application.

Structural Synthesis of a Class of 2R2T Hybrid Mechanisms

Conventional overconstrained parallel manipulators have been widely studied both in industry and academia,however the structural synthesis of hybrid mechanisms with additional constraints is seldom studied,especially for the four degrees of freedom（DOF） hybrid mechanisms.In order to develop a manipulator with additional constraints,a class of important spatial mechanisms with coupling chains（CCs） whose motion type is two rotations and two translations（2R2T） is presented.Based on screw theory,the combination of different types of limbs which are used to construct parallel mechanisms and coupling chains is proposed.The basic types of the general parallel mechanisms and geometric conditions of the kinematic chains are given using constraint synthesis method.Moreover,the 2R2T motion pattern hybrid mechanisms which are derived by adding coupling chains between different serial kinematic chains（SKCs） of the corresponding parallel mechanisms are presented.According to the constraint analysis of the mechanisms,the movement relationship of the moving platform and the kinematic chains is derived by disassembling the coupling chains.At last,fourteen novel hybrid mechanisms with two or three serial kinematic chains are presented.The proposed novel hybrid mechanisms and construction method enrich the family of the spatial mechanisms and provide an instruction to design more complex hybrid mechanisms.

Structural Synthesis of 3T2R Five-Degree-of-Freedom Hybrid Mechanism

The structural synthesis of mechanisms is a prerequisite of mechanical design,thereby,it is necessary to pay attention to the structural synthesis of mechanisms,especially for the type synthesis of hybrid mechanisms.A very simple yet very effective method was presented for the structural synthesis of hybrid mechanisms based on the set theory.The basic concept and mathematical operation of G_F set were firstly introduced.Based on the G_F set,a type synthesis principle for serial mechanisms,parallel mechanisms and hybrid mechanisms was presented,especially,a detailed algorithm of type synthesis for hybrid mechanisms was proposed as well.It is shown that type synthesis of hybrid mechanisms can be developed by the combination of elements of G_F set and rotation axis transfer theorem.Further investigation shows that structures of 3T2R fivedegree-of-fteedom(DoF) hybrid mechanism only have one category,i.e.,G_F^I.Finally structural synthesis of 3T2R hybrid mechanism for this category is illustrated with example to demonstrate the applicability of the type synthesis principle.

Structural Synthesis and Workspaces of Serial Robotic Chains with 7 Axes

Redundant serial robot kinematic chains with seven axes are an extension of classical 6-axis ones. The structural synthesis of these structures is useful to provide a working basis, including for the promotion of new structures with 7 axes, besides some already existing and applied structures. This paper summarizes kinematic chain structures using a combinatorial method by listing all possible variants of the structures with 7 axes, obtained by adding a rotational or translational coupling, in a parallel or perpendicular position, against the guiding structure with 6 axes consisting of two distinct modules： positioning module （3 axes） and orientation module （3 axes）. Representation of proper workspaces can help the designer in choosing the structure with maximum functionality for a given application.

Autonomy-subnet based structural synthesis and liveness guarantying policy of Petri net model of flexible manufacturing system

In this paper, an autonomous subnet based structural methodology forbottom-up synthesis of Petri Nets for Flexible Manufacturing Systems is proposed.Furthermore, the theoretical analysis of the model constructed by the method is carried byintensively using model's structural information, such as invariants, siphons, etc.. As aresult, the analysis leads us to draw the general conclusion that the model obtained isconservativeness and thus bound, and characterize its liveness in terms of zero-markingminimal siphons. It is based on model's structural information that distinguishes ourmethod from others. in line of this thought, a liveness guarantying policy for the obtainedmodel is proposed. Some control subnets are merged into the original model according tothe proposed synthesis rules in this paper to ensure that no minimal siphons are emptiedin any state, therefore the liveness is guaranteed. As a result, a live, conservative andrevertible Petri Nets is obtained. A practical example is also presented to demonstrate theeffectiveness of this method.

SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF IN-COMPLETE CUBANE CLUSTER C(MoCu_3S_3) (O)(μ-dtp)(PPh_3)_3]

A new mixed-metal sulfido incomplete cubane cluster [(MoCuS3) (O) (μ-dtp) (PPh3)3] Cdtp = S2P (OC2H5)2] has been prepared by reaction of (NH4)2MoOS3 with Cu(dtp) (PPh3)2 in dimethylformamide solution. It crystallizes in the triclinic space group P1, a = 13.810(5), b = 19. 753(5), c=11. 719(4) A. α=99. 42(2), β=107. 24(3),γ=88. 05(3)°, V = 3012(2)A3, Dc = l. 51g/cm3and Z = 2. Final R=0. 046, Rw = 0. 056 for 7700 unique intensity data(I≥3σ(I)). The central unit [MoCu3S3]3+ can be described as a distorted incomplete cube with one missing corner. The Mo atom is tetrahedrally coordinated by three μ3-S atoms and one terminal O atom. Two Cu atoms are tetrahedrally coordinated whereas the third Cu atom has a highly distorted trigonal environment. The mean Mo - Cu bond length is 2. 752A. The Cu...Cu distances are in the range of 3. 200(1) -3. 740(1) A which are too long to form bonds.

Synthesis and Structural Investigation of （LaO）_3BO_3 with Eu^（3＋） as Luminescent Probe

Europium (Eu￣(3+)) doped polycrystalline (LaO)_3BO_3 has been synthesized by solid state reaction with Li_2CO_3 as flux at 1200℃ for 10 h in air. X- ray powder diffraction shows that ( LaO)_3BO_3 crystallizes in a monoclinic cell [a= 0. 69214 (9)nm , b=1. 2929(3) nm , c=1. 4590 (3 ) nm . β= 99. 35 (2)°,V= 1. 2882(4 ) nm￣3 and Z= 8] with a possible space group of P2_1/m or P2_1. The predominance of electric-dipole transition ￣5D_0→ ￣7F_2 in the fluorescence spectrum , as well as the splitting of the￣7F_j ground states of Eu￣(3+) reveals that the lanthanum atoms distribute in the sites with C_1 or C_s symmetry in this structure.

Topology Structure Synthesis and Analysis of Spatial Pyramid Deployable Truss Structures for Satellite SAR Antenna

Many attentions for structural synthesis are paid to planar linkages and parallel mechanisms, while design novel pyramid deployable truss structure（PDTS） of satellite SAR mainly depends on experience of designer. To design novel configuration of PDTS, a two-step topology structure synthesis and analysis approach is proposed. Firstly, a conceptual configuration of PDTS is synthesized. Weighted graph and weighted adjacency matrix are established to realize topological description for PDTS. Graph properties are then summarized to distinguish differentia between PDTS and other type structures. According to graph properties, a procedure for synthesis conceptual configuration of PDTS is presented. Secondly, join relationship of components in a PDTS is analyzed. Kinematic chain and corresponding incidence/adjacency matrix are employed to analyze join relationship of PDTS. Properties and simplified rules of kinematic chain are extracted to construct kinematic chain. A procedure for construction kinematic chain of PDTS is then established. Finally, with this two-step approach all 11 rectangular pyramid deployable structures whose folded state is planar are discovered and their kinematic chains are constructed. Based on synthesis results, a novel deployable support structure for satellite SAR is designed. The proposed research can be applied to obtain some novel PDTSs, which is of great importance to design some novel deployable support structures for satellite SAR antenna.

STRUCTURE SYNTHESIS OF 4-DOF PARALLEL ROBOT MECHANISMS BASED ON SCREW THEORY

Structural synthesis for 4-DOF parallel manipulators using screw theory issystematically studied. Motion properties and constraint conditions of 4-DOF parallel manipulatorsaccording to the relationship between screw and reciprocal screw are analyzed. Mathematicalexpressions for constraint screws and twist screws of moving platform are constructed, and allpossible limbs, which provide one or more force constraints, are enumerated. Finally, a parallelmanipulator with 3-rotation-DOF and 1-translation-DOF is used as an example to describe thesynthesis procedure for symmetrical and non-symmetrical 4-DOF parallel manipulators.

Synthesis,Crystal Structure and Thermal Decomposition of a New Energetic Potassium Salt of Bis(dinitromethyl)difurazanyl Ether

A new energetic organic potassium salt bis（dinitromethyl）difurazanyl ether potas- sium salt [K2（BDFE）] was synthesized, and structurally characterized by elemental analysis, IR spectra, t3C NMR and single-crystal X-ray diffraction. K2（BDFE） crystallizes in monoclinic system, space group C2/c with a = 17.342（3）, b = 12.6943（17）, c = 8.0972（11） A, β = 110.630（2）°, V = 1668.3（4） A3, Z = 4, Dc = 2.000 g/cm3, F（000） = 1000,μ= 0.675 mm-1, S = 1.058, the final R = 0.0499 and wR = 0.1452. The K ion is eight-coordinated with eight O atoms from one water molecule and four bis（dinitromethyl）difurazanyl ethers （BDFE）, forming a distorted dodecahedral structure. Thermal decomposition of the title complex was studied by using DSC and TG-DTG. There are primarily two exothermic decomposition processes between 200 and 370 ℃.

Synthesis,Crystal Structure,DFT Studies and Biological Activity of a Novel Schiff Base Containing Triazolo[4,3-a]pyridine Moiety

The novel Schiff base（E）-8-chloro-NA-（4-（dimethylamino）benzylidene）-[1,2,4]triazolo[4,3-a]pyridine-3-carbohydrazide was synthesized and characterized by ^1H NMR,MS,elemental analysis and X-ray diffraction.The compound crystallizes in the monoclinic space group P2_1/c with a = 7.091（2）,b = 10.750（3）,c = 21.380（6） A,β = 96.299（6）°,V = 1619.7（8） A^3,Z = 4 and R = 0.0351.Theoretical calculation of the title compound was carried out with the B3LYP/6-31 G basis set.The frontier orbital energy and atomic net charges were discussed.It is found that the experimental data show good agreement with the calculated values.And the compound exhibits good antifungal activity against Stemphylium lycopersici（Enjoji） Yamamoto.

ISOLATION, STRUCTURE ELUCIDATION AND SYNTHESIS OF A NEW PRENYLATED FLAVONOL, MAACKIAFLAVONOL, FROM MAACKIA TENUIFOLIA

A new prenylated flavonol, maackiaflavonol, was isolated from the ethanol extract of the roots of Maackia tenuifolia. Its structure was elucidated as 7-hydrox-8-prenylflavonol by means of spectroscopic analysis (UV, IR, MS, NMR and 1H-1H COSY) and confirmed by total synthesis.

Synthesis,Crystal Structure,DFT Studies and Antifungal Activity of 5-(4-Cyclopropyl-5-((3-fluorobenzyl)sulfonyl)-4H-1,2,4-triazol-3-yl)-4-methyl-1,2,3-thiadiazole

5-（4-Cyclopropyl-5-（（3-fluorobenzyl）sulfonyl）-4H-1,2,4-triazol-3-yl）-4-methyl-1,2,3-thiadiazole was synthesized and recrystallized from Et OH. The compound was characterized by ^1H NMR,MS,elemental analysis and X-ray diffraction. The structure-active relationship and the antifungal activity based on density functional theory calculation（DFT） and antifungal activities were investigated. The compound crystallizes in the monoclinic space group P121/n1 with a = 8.929（3）,b=12.715（4）,c=15.161（5） A°,β = 106.142（3）o,V = 1653.3（9） A°3,Z = 4 and R = 0.0393 for 3930 observed reflections with I 〉 2σ（I）. Theoretical calculation of the title compound was carried out with B3LYP/6-31G（d,p）. The full geometry optimization was carried out using the 6-31G（d,p） basis set.The frontier orbital energy and atomic net charges were discussed. The observed results of the compound have been compared with theoretical results and the experimental data show good agreement with the calculated values. The compound exhibits good antifungal activity.

Synthesis,Crystal Structure and Properties of A Triphenyltin Schiff Complex with Salicylidene-2-aminophenol

The triphenyltin complex with salicylidene-2-aminophenol （C31H24NO2Sn, 1） has been synthesized and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, and X-ray single-crystal diffraction. The complex crystallizes in monoclinic system, P21/c space group with a = 1.09515（8）, b = 1.17739（8）, c = 2.29075（14） nm, β = 117.070（4）°, V = 2.6302（3） nm3, Z = 4, Dc = 1.417 g/cm3, ？ = 0.999 mm–1, F（000） = 1123, R = 0.0472 and wR = 0.1169. X-ray single-crystal diffraction showed that 1 demonstrates a one-dimensional chain structure. The quantum chemical calculation of 1 has been investigated. Complex 1 emits fluo- rescence at 558 nm and exhibits certain inhibitory activity against NCI-H460, A549 and MCF-7.

Synthesis,Crystal Structure and Antifungal Activity of 8-Chloro-3-((4-chlorobenzyl)-thio)[1,2,4]triazolo[4,3-a]pyridine

The title compound 8-chloro-3-（（4-chlorobenzyl）thio）-[1,2,4]triazolo[4,3-a]pyridine was prepared from 1-chloro-4-（chloromethyl）benzene and 8-chloro-[1,2,4]triazolo[4,3-a]pyridine-3（2H）-thione in the presence of Na OH, and its structure was determined by X-ray diffraction analysis. The crystal is of triclinic system, space group P1 with a = 6.8264（6）, b = 7.5890（4）, c = 13.0960（7） A, α = 93.447（4）, β = 98.772（6）, γ = 92.615（6）o, V = 668.26（8） A3, Z = 2, the final R = 0.035 and wR = 0.09 for 2259 observed reflections with I 〉 2σ（I）. The preliminary biological test showed that the title compound has activities against Stemphylium lycopersici（Enjoji） Yamamoto, Fusarium oxysporum. sp. cucumebrium, and Botrytis cinerea with inhibitory to be 51.19%, 62.02% and 15.56%, respectively.

Synthesis and Crystal Structure of 3-(2-Hydroxybenzly)-4-(4-Hydroxybenzylideneamino)-(1H) -1,2,4-Triazole-5-Thione and Its Antibacterial Activities

The title compound C15H12N4O2S was synthesized by the reaction of 3-（2-hydroxybenzyl）-4-amino-（1H）-1,2,4-triazole-5-thione with 4-hydroxybenzaldehyde in ethanol and characterized by IR, ^1H NMR spectra and elemental analysis. Its structure has been determined by X-ray diffraction analysis. The crystal belongs to monoclinic, space group C2/c with a = 27.990（3）, b = 13.1326（14）, c = 7.9770（8） A, β= 105.787（2）°, V = 2821.6（5）A^3, Z = 8, Mr= 312.35,μ= 0.243 mm^-1, Dc = 1.471 g/cm^3 and F（000） = 1296. The structure was solved by direct methods.and refined to a Rint value of 0.0388. The crystal structure involving in intermolecular N-H…S and O-H…S hydrogen bonds is observed, meanwhile intramolecular O-H…N hydrogen bond is also found. Their biological activities have been measured. The results show that this type of compound has certain antibacterial activity for Staphylococous aureus and Bacillus subtilis.

Synthesis,Crystal Structure and Plant Growth Regulatory Activity of 1-(3-Amino-[1,2,4]triazol-1-yl)-3,3-dimethyl-butan-2-one

The title compound 1-（3-amino-[1,2,4]triazol-1-yl）-3,3-dimethyl-butan-2-one（3） was synthesized by Hofmann-alkylation reaction of 1-chloro-3,3-dimethyl-butan-2-one（1） and ~1H-[1,2,4]triazol-3-ylamine（2） with equal amount of K_2CO_3 as acid acceptor. The structure of compound 3 was characterized by ~1H NMR, 13 C NMR, HRMS and single-crystal X-ray diffraction. The compound crystallizes in the monoclinic system, space group P21/n with a = 5.7227（8）, b = 27.924（4）, c = 6.2282（7） ？, β = 101.892（11）°, V = 973.9（2） ？~3, Z = 4, T = 180.00（10） K, μ（MoKα） = 0.087 mm^（-1）, Dc = 1.243 g/cm^3, 3832 reflections measured（3.648≤θ≤26.022°）, 1916 unique reflections（Rint = 0.0359, Rsigma = 0.0572） used in all calculations. The final R = 0.0557（I 〉 2σ（I）） and w R = 0.1276（all data）. Bioassay showed that 3 displayed excellent activity as plant growth regulator with inducing lateral root formation and enhancing primary root elongation at 0.27 mmol/L（50 ppm） in soybeen（He Feng-50）. Good water solubility was found with 50 mg in 1 m L of water. Therefore, application of 3 in agriculture is more environmentally friendly due to cosolvent-free condition, and results in improved abiotic-stress tolerance by affecting the root growth. And furthermore, it can be used as a precursor to investigate the function of regulating plant root growth.

Synthesis,characterization,and antioxidant activity of carboxymethyl chitosan derivatives containing sulfonium salt

To improve the solubility and bioactivity of chitosan,a new class of carboxymethyl chitosan derivatives possessing sulfonium salts was successfully designed and synthesized,including Methyl sulfi de carboxymethyl chitosan(MCMCS),Ethyl sulfi de carboxymethyl chitosan(ECMCS),Propyl sulfi de carboxymethyl chitosan(PCMCS),and Butyl sulfi de carboxymethyl chitosan(BCMCS).To determine the structure of the new class of the derivatives,methods of the Fourier transform infrared spectroscopy(FT-IR),^(1)H nuclear magnetic resonance spectrometer(^(1)H NMR),and^(13)C nuclear magnetic resonance spectrometer(^(13)C NMR)were used.Moreover,the antioxidant activity of the derivatives for three types of free radicals,i.e.,hydroxyl radical,superoxide radical,and 1,1-diphenyl-2-picrylhydrazyl(DPPH)radical was evaluated in vitro.In addition,the L929 cells were adopted to test the cytotoxicity of chitosan and its derivatives by CCK-8 assay.The class of the carboxymethyl chitosan derivatives showed a strong scavenging ability against the three free radicals at 1.6 mg/mL,with scavenging rate of over 70%and some up to 100%.At this high rate,the overall cell viability in the toxicity test reached more than 80%,indicating that the synthetic derivative had a little cytotoxicity.The results show that the introduction of carboxymethyl group to chitosan increased the water-solubility of chitosan,and the combination of sulfonate ions with diff erent chain lengths further enhanced the antioxidant activity of chitosan.Therefore,the sulfonium-containing carboxymethyl chitosan derivatives had excellent bioactivity with good application prospects in food,biomedicine,and medical fi elds.

Synthesis, Structure and Antimicrobial Activity of 9,9-Dimethyl-9,10-dihydrospiro[benzo[a]-xanthene-12,3'-indoline]-2',11(8H)-dione

One novel spiro-compound（C_（26）H_（21）NO_3） has been synthesized and characterized by means of NMR spectroscopy,elemental analyses and X-ray diffraction. The single crystal belongs to the monoclinic system,space group P21/c with a = 8.8039（7）,b = 24.123（2）,c = 10.0751（9） ？,β = 108.403（3）°,M3r = 395.44,V = 2030.3（3） ？~3,Z = 4,D_c = 1.294 g/cm,F（000） = 832.0,μ = 0.085 mm^（-1）,R = 0.0801 and wR = 0.2228. The title compound shows good activities against Micrococcus tetragenus,Bacillus cereus,Bacillus subtilis,Staphylococcus aureus,S.albus and Escherichia coli.