Structure of the Intermetallic Compound Ni_3Al Synthesized under Compression of the Powder Mixture of Pure Elements Part Ⅰ: Phase Composition and Microstructure of Main Phase

It was shown by TEM and X-ray analysis that there are four types of grains of the main Ni3Al phase in the structure of the intermetallic obtained by the self-propagation high temperature method (SHS). Every type of grains has its own domain and dislocation structure. There are mono- and polydomains with and without dislocations. The grains of the main phase of monoand polydomains without dislocations and polydomains with dislocations were formed by diffusion in the solid phase. In these conditions NiAl3 phase is located on the grain boundary of the main phase. The Ni2Al3 phase is located at the triple joints of the main phase.

TOUGHENING OF IN SITU SYNTHESIZED MoSi_2-SiC COMPOSITE AT ROOM TEMPERATURE

The in situ synthesized MoSi2-SiC composite is proved to be of higher fracture toughness than the monolithic MoSi2. The TEM and HREM study reveals that the interface between MoSi2/SiC is of direct atomic bonding without any amorphous glassy phase, such the SiO2 structure. Based on the fractography and the observation of crack propagation path from indentation, it is concluded that the toughening of such composite at room temperature can be attributed to the high interfacial binding energy, the refinement of the MoSi2 matrix and the deflection and bridging behavior in the crack propagation.

Preparation and Luminescence Properties of Terbium-Sal Complex In-situ Synthesized in Silica Matrix by a Two-Step Sol-Gel Process

In-situ synthesis of terbium complex with saiicylic acid (Sal) in silica matrix was made by a two-step sol-gel process. The terbium complex with salicylic acid was formed in sol-gel derived silica gel, and confirmed by the luminescence excitation spectra and infrared(IR) spectra. As compared to the pure terbium complex powder, the silica gel containing terbium complex exhibits its characteristic emission and presents a longer fluorescence lifetime than that for the pure complex. The luminescence properties of the complex containing silica gel were investigated and compared with that of both terbium doped the silica gel and the pure complex powder. The reasons leading to the above results were also discussed.

Structure of the Intermetallic Compound Ni_3Al Synthesized under Compression of the Powder Mixture of Pure Elements Part Ⅱ: Influence of Alloying by Boron on the Phase Composition and the Microstructure of Grains of the Main Phase

The Ni3B phase was formed when boron （0.5 at. pct B） was added to the intermetallic of sto- ichiometric and off-stoichiometric （Ni-24 at. pct Al） compounds. In the alloy of stoichiometric composition the particles of Ni3B phase has the size around 0.1μm and is located on the grain boundary of the main phase. The decreasing of concentrations of Al in the ofF-stoichiometric alloy leads to increase in the degree of the long-range order parameter, increasing the concen- trations of boron in the solid solution and decreasing its localization on the grain boundary. Microalloying of boron leads to increasing in the fraction of grain monodomains with disloca- tions up to 0.7 in the alloy of the off-stoichiometric composition and up to 1 in the alloy of the stoichiometric composition. It was established the correlation between the degree of the concentration inhomogeneity, average density of the dislocations and the average long range-order parameter.

Use of the Newly Synthesized Aqueous Polyurethane Acrylate Binders for Printing Cotton and Polyester Fabrics

The use of the four new synthesized polyurethane acrylate binders in the pigment print paste for screen printing cotton and polyester fabrics and pigment fixation through the polymerization process of the binder by using the thermofixation technique as well as the UV curing technique was studied. The effect of changing time and temperature of thermofixation, and the time of UV curing on the color strength, and prints fastness properties were also studied. The results showed that, the newly synthesized polyurethane acrylate binders could be successfully used for pigment fixation on cotton and polyester using the two fixation techniques and in general their prints possessed better color strength values as compared to those obtained upon using the selected commercial binders.

STRUCTURE AND BINDING STATE OF CN_x FILMS SYNTHESIZED BY FACING TARGETS SPUTTERING

CN x films were made by a facing targets sputtering ( FTS) systemon the  Si(100) substrate under different  N 2 partial pressure.  XRD, XPS, FTIR and Raman Spectroscopy( RS) were measured to investigate the structure and the binding state of the film. The films are amorphous and the  N/C increases with the  N 2 partial pressure increasing and reaches 0 46 when the  N 2 pressure is 100%. The N incorporated  C forms N sp 2C and N sp 3C mainly and there is a small amount of  C≡N.

Nano-composite Particles Synthesized by a Hydrogen Arc Plasma

Nano-composite particles can be synthesized by a hydrogen arc plasma method, which possesses the advantages of high productivity, controllable size distribution and low electric energy consumption comparing with conventional gas condensation method. With this method, not only the nanoparticles of metals and alloys, but also the nano-composite particles with shell structure can be synthesized. The microstructures, compositions and the formation mechanism of the nano composite particles were

Synthesized Optimization of Triangular Mesh

Triangular mesh is often used to describe geometric object as computed model in digital manufacture,thus the mesh model with both uniform triangular shape and excellent geometric shape is expected.But in fact,the optimization of triangu- lar shape often is contrary with that of geometric shape.In this paper,one synthesized optimizing algorithm is presented through subdividing triangles to achieve the trade-off solution between the geometric and triangular shape optimization of mesh model.The result mesh with uniform triangular shape and excellent topology are obtained.

Synthesized flavanoid-derived ligand reduced dengue virus type-2 replication in vitro

Objective: To investigate the antiviral property of a lead ligand, YK51 that was synthesized based on the flavanoid of a natural product toward dengue virus type-2(DENV2)replication.Methods: c RNA was isolated from HepG2 cells inoculated with 1 000 median tissue culture infective dose of DENV2 and treated with different doses of the ligand followed by RT-PCR to quantify the virus gene copies. Confocal microscopy of actin and tubulin redistribution was also performed.Results: The quantitative RT-PCR result showed reduction of the DENV2 gene copies as the ligand concentration was increased. The confocal microscopy result showed increase in the tubulin intensity(79.6%) of infected BHK21 cells treated with the ligand,compared with the non-treated cells(54.8%). The 1.5-fold increase in the intensity of tubulin suggested that the ligand inhibitory effect stabilized the cellular microtubule structure.Conclusions: The synthesized ligand YK51 reduced DENV2 viral load by inhibiting virus replication thus is highly potential to be developed as antiviral agent.

Consolidation and Compression Property of Nanocrystalline NiAl Synthesized by Mechanical Alloying

The mixture of pure nickel and aluminum powders in the composition of Ni50AI50 was subjected to high energy ball milling. The high energy ball milling to 30 h resulted in the formation of a nanocrystalline NiAl with a grain size of about 10 nm. The as-milled NiAl powder was hot-pressed and the compact with a density of 90% was obtained. It was showed that heating to900℃ and holding for more than 2 h failed to induce the coarsening of the fine nanocrystalin the material, the tendency of grain growth was weak. Compression testing showed that thecompression ductility at room temperature reached about 7%. The ductility increased with theexperimental temperature while the strength decreased drastically at elevated temperature.

Crystallization Behaviour of Laser Synthesized Nanometric Amorphous Si_3N_4 Powders

The crystallization behaviour of the laser synthesized nanometric amorphous Si3N4 powders with the particle size of 15 nm in diameter has been studied between 1200° and 1700℃ by XRD,TEM and FTIR techniques. A small amount of β-Si3N4 formed at 1250℃ and increased slowly until the α- β transformation happened at 1700℃, whereas α-Si3N4 appeared at 1300℃ andincreased rapidly between 1500-1600℃. The formation of β phase at the lower temperature was caused by the nitridation of free Si due to the preexisted β-nuclei in the Si3N4 particles, whereasthe α phase was formed by solid crystallization from the amorphous matrix. There were α and β SiC formed at 1700℃ due to the presence of Sio and Co gases in the system. FTIR analysis shows that two new IR absorption at 1356 and 1420 cm-1, and an overall strong absorption in wide wavenumber range resulted from the powders annealed at 1600 and 1700℃

Characterization of Nanocrystalline Intermetallic Compound NiAl Synthesized by Condensation

Nanocrystalline intermetallic compound NiAl was Synthesized by evaporating NiAl master alloy in inert-gas followed by in situ compaction, and its structure was studied by means of X-ray diffractometry and transmission electron microscope. Experimental results reveal that the assynthesized nanocrystalline sample has a mean grain size of less than 10 nm and it is dominantly composed of the cubic structure phase NiAl. However, nanocrystalline Ni3Al as a trace phase mixed in NiAl phase, was also detected by transmission electron microscope observation.

Synthetic Biochemistry and Synthesized Consciousness

The aim of the study is the possibility of synthesis and study of the properties of“synthetic consciousness”by modifying various chemical elements of the genome of synthetic biochemistry.We have proposed a new approach to synthesize“synthetic consciousness”using synthetic biochemistry.

Antibacterial screening of silver nanoparticles synthesized by marine micro algae

Objective:To explore the biosynthesis of silver nanoparticles synthesized by marine microalgae. Methods:Marine microalgae was collected from Central Marine Fisheries Research Institute (CMFRI,tuticorin) and cultured in the lab.Silver nanoparticles synthesis were observed in normal and microwave irradiated microalgae and screened against human pathogens for the presence of antimicrobials.Results:The presence of silver nanoparticle was confirmed by UV-Visible spectroscopy at 420 nm by the presence of plasmon peak.Further confirmation was done by scanning electron microscope(SEM).Conclusions:These results not only provide a base for further research but are useful for drug development in the present and future.

Microstructural evolution and mechanical behavior of in situ synthesized MgAl_(2)O_(4)whiskers reinforced 6061 Al alloy composite after hot extrusion and annealing

In situ synthesized MgAl2O4whiskers reinforced 6061 Al alloy composites were fabricated by a powder metallurgy method.Nano-sized MgAl2O4spinel whiskers distributed uniformly in 6061 Al alloy matrix without any interfacial product and laid along the extrusion direction after hot extrusion.As-extruded composite samples were annealed at 530,580,600 and 630℃for 1 h and examined by electron backscattered diffraction to investigate the recrystallization behavior of obtained composites.Microstructure and texture evolution was investigated,and it is found that the recrystallization process is inhibited by whiskers because of Zener pinning.Slender fibrous grains remain until 630℃,and deformation textures still exist even in specimen annealed at 630℃.Hardness and tensile tests show that the completely recrystallized sample has an ultimate tensile strength of 218 MPa and a hardness of HV52 compared with 283 MPa and HV 69 of the unannealed sample.Mechanical properties of the annealed samples decline slightly with annealing temperature increasing up to 600℃.

Rapid changes of microsatellite flanking sequence in the allopolyploidization of new synthesized hexaploid wheat

It was suggested that the rapid changes of DNA sequence and gene expression oc- curred at the early stages of allopolyploid formation. In this study, we revealed the microsatellite (SSR) differences between newly formed allopolyploids and their donor parents by using 21 primer sets specific for D genome of wheat. It was indicated that rapid changes had occurred in the “shock” process of the allopolyploid formation between tetraploid wheat and Aegilops tauschii. The changes of SSR flanking sequence resulted in appearance of novel bands or disappearance of parental bands. The disappearance of the parental bands showed much higher frequencies in comparison with that of appearance of novel bands. Disappearance of the parental bands was not random. The frequency of disappearance in tetraploid wheat was much higher than in Ae. tauschii, i. e. the disappearance frequency in AABB genome was much higher than in D genome. Changes of SSR flanking sequence occurred at the early stage of F1 hybrid or just after chro- mosome doubling. From the above results, it can be inferred that SSR flanking sequence region was very active and was amenable to change in the process of polyploidization. This suggested that SSR flanking sequence probably had special biological function at the early stage of ploy- ploidization. The rapid and directional changes at the early stage of polyploidization might con- tribute to the rapid evolution of the newly formed allopolyploid and allow the divergent genomes to act in harmony.

Studying the urban hierarchical pattern and spatial structure of China using a synthesized gravity model

The Gravity Model(GM), one of the most classic models adopted by the domain of social sciences from physics, has been widely used to study the interactions between social identities. Previous research that has used the Gravity Model to study the interactions among cities have mostly used a single variable, such as population or GDP, to represent a city, which does not provide a comprehensive depiction of a city's influence. This paper develops a Synthesized Gravity Model(SGM) based on the traditional Gravity Model to study the evolution of the hierarchy of the Chinese urban system since the mid-1990 s. Under this model, socioeconomic variables are synthesized and are represented by the Influential Factor, while the Function Distance is derived from a Network Analysis that is based on multiple transportation methods. As an improvement on the GM, the SGM is used to accurately establish and represent the nodal structure of China's urban system, the evolution of its hierarchical structure,and the relationships that exist between the nodal structure and socioeconomic factors. The results based on the SGM indicate that China's national urban system is characterized by the emergence of urban clusters with stronger inter-city interactions since the 1990 s. However, the development among cities within certain urban clusters is not even, although the general pattern indicates a lessening inequality amongst cities. Spatially, while most cities at the top of the hierarchy are located in Eastern China, cities in the center and the west of the country are also gaining higher positions in the hierarchy over time. This paper is dedicated to improving the traditional GM in the applications of urban studies, while the system of Chinese cities is used to validate the SGM.

The first protein ever synthesized in vitro—a personal reminiscence of the total synthesis of crystalline insulin

The total synthesis of crystalline bovine insulin started in 1958 was fully accomplished in 1965. This formidable task was a collaboration of the Institute of Biochemistry in Shanghai,

Challenges and advances in genome mining of ribosomally synthesized and post-translationally modified peptides (RiPPs)

Ribosomally synthesized and post-translationally modified peptides(RiPPs)are a class of cyclic or linear peptidic natural products with remarkable structural and functional diversity.Recent advances in genomics and synthetic biology,are facilitating us to discover a large number of new ribosomal natural products,including lanthipeptides,lasso peptides,sactipeptides,thiopeptides,microviridins,cyanobactins,linear thiazole/oxazole-containing peptides and so on.In this review,we summarize bioinformatic strategies that have been developed to identify and prioritize biosynthetic gene clusters(BGCs)encoding RiPPs,and the genome mining-guided discovery of novel RiPPs.We also prospectively provide a vision of what genomics-guided discovery of RiPPs may look like in the future,especially the discovery of RiPPs from dominant but uncultivated microbes,which will be promoted by the combinational use of synthetic biology and metagenome mining strategies.