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.

A 1-GHz Charge Pump PLL Frequency Synthesizer for IEEE 1394b PHY

The design procedure of an 1-GHz phase-locked loop （PLL）-based frequency synthesizer used in IEEE 1394b physical （PHY） system is presented in this paper. The PLL＇s loop dynamics are analyzed in depth and theoretical relationships between all loop parameters are clearly described. All the parameters are derived and verified by Verilog-A model, which ensures the accuracy and efficiency of the circuit design and simulation. A 4-stage ring oscillator is employed to generate 1-GHz oscillation frequency and is divided into low frequency clocks by a feedback divider. The architecture is a third-order, type-2 charge pump PLL. The simulated settling time is less than 4μs. The RMS value of period jitter of the PLL＇s output is 2.1 ps. The PLL core occupies an area of 0.12 mm2, one fourth of which is occupied by the MiM loop capacitors. The total current consumption of the chip is 16.5 mA. The chip has been sent for fabrication in 0.13 μm complementary metal oxide semiconductor （CMOS） technology.

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.

B-C Bond in Diamond Single Crystal Synthesized with h-BN Additive at High Pressure and High Temperature

The synthesis of diamond single crystal in the Fe64Ni36-C system with h-BN additive is investigated at pressure 6.5 GPa and temperature range of 1300-1400℃. The color of the obtained diamond crystals translates from yellow to dark green with increasing the h-BN addition. Fourier-transform infrared （FTIR） results indicate that sp2 hybridization B-N-B and B-N structures generate when the additive content reaches a certain value in the system. The two peaks are located at 745 and 1425cm-1, respectively. Fhrthermore, the FTIR characteristic peak resulting from nitrogen pairs is noticed and it tends to vanish when the h-BN addition reaches 1.1 wt%. Furthermore, Raman peak of the synthesized diamond shifts down to a lower wavenumber with increasing the h-BN ~ddition content in the synthesis system.

Optimization of Gas Sensing Performance of Nanocrystalline SnO_2 Thin Films Synthesized by Magnetron Sputtering

Tin oxide （SnO2） is one of the most promising transparent conducting oxide materials, which is widely used in thin film gas sensors. We investigate the dependence of the deposition time on structural, morphologicaJ and hydrogen gas sensing properties of SnO2 thin films synthesized by dc magnetron sputtering. The deposited samples are characterized by XRD, SEM, AFM, surface area measurements and surface profiler. Also the H2 gas sensing properties of SnO2 deposited samples are performed against a wide range of operating temperature. The XRD analysis demonstrates that the degree of crystallinity of the deposited SnO2 films strongly depends on the deposition time. SEM and AFM analyses reveal that the size of nanoparticles or agglomerates, and both average and rms surface roughness is enhanced with the increasing deposition time. Also gas sensors based on these SnO2 nanolayers show an acceptable response to hydrogen at various operating temperatures.

Structure and Tribological Property of TiBN Nanocomposite Multilayer Synthesized by Ti-BN Composite Cathode Plasma Immersion Ion Implantation and Deposition

A Ti-BN complex cathode is made from Ti and h-BN powders by the powder metallurgy technology, and TiBN coating is obtained by plasma immersion ion implantation and deposition with this Ti-BN composite cathode. The TiBN coating shows a self-forming multilayered nanocomposite structure while with relative uniform elemental distributions. High resolution transmission electron microscopy images reveal that the multilayered structure is derived from different grain sizes in the nanocomposite. Due to the existence of h-BN phase, the friction coefficient of the coating is about 0.25.

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 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 Ni_3B 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 Ni_3B 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.

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 studied

Influence of Impurity Na2O on Crystalline Structure of Cordierite Synthesized from Aluminum Sludge

Waste aluminum sludge, talc powder and clay were used to synthesize cordierite in this research. The impurities, such as Fe2O3, CaO, K2O and Na2O, in the raw materials have some influence on the structures and properties of the materials. In this paper, we mainly discuss the impact of impurity Na2O on the structure of cordierite, based on which the permitted amount of Na2O was determined. The results show that Na2O with the amount less than 0.6% has little influence on the cordierite formation; while when its amount increasing from 0.6% to 0.7%, the content of cordierite decreases from 86% to 84% and the permitted amount for Na2O in the raw materials is less than 6% with the best amount less than 0.3%. X’pert plus software analysis results show the impurity Na2O has no influence on the cordierite space group and only the lattice parameters vary slightly; but it has much influence on the structure of Mg-Al spinel and the lattice parameters are much changed.

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.

AN EASY ROUTE TO SYNTHESIZE COPPER(I) COMPLEXES Cu_2(Ph_2PCH_2PPh_2)_2(NO_a)_2 AND Cu(Ph_2PCH_2CH_2PPh_2)(NO_a). THEIR CHARACTERIZATION AND ELECTROCHEMISTRY

Binuclear Cu(Ⅰ) complex [Cu(dppm)(NO_3)]2 (dppm=Ph_2PCH_2PPh_2) and mononuclear Cu(Ⅰ) complex [Cu(dppe)(NO_3)] (dppe=Ph_2PCH_2CH_2PPh_2) have been synthesized by the ligand-reduction reaction of cupric nitrate with dppm and dppe in methanol and characterized by means of ICP, elemental analyses, molecular weight determination, TG, ^(31)P-NMR, IR and Raman spectra; their electronic conductivities and CV waves have also been measured. Results show that dppm coordinates to the Cu(Ⅰ) atoms as a bridging bidentate ligand and dppe as a chelating bidentate ligand, (NO_3)^(-1) behaves as a chelating bidentate ligand in both of the newly prepared complexes.

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.

PROPERTIES OF （Y．Gd） BO_3： Eu^（3＋）PHOSPHORS SYNTHESIZED BY MICROWAVE HEATING METHOD

In this peper we have synthesized powder crystal form (Y,Gd) BO3:Eu(3+)Phosphors by microwave heating method. ItS structure belongs to hexagonal system with lattice parameters a=0.3796,c=0. 8835. Its excitation spetra peaks at 239.0nm and 240. 0nm monitored at the emission of 589nm and 612nm respectively, the half peak width is 40nm. Under 240nm excitation the phosphors show a strons oranse-red luminescence, the fluorescent intensity ratio for I589/I612 is 1.9/1

Frequency Synthesizer of Short-Wave SFH/MFSK System

The technology of DDS-driven PLL is introduced and a new scheme of frequency synthesizer which is suitable for SW SFH/MFSK System is presented in this paper. Based on the special requirement of SW communication, a model of the scheme is given and the results show that the frequency synthesizer has small frequency insteval (≤0.1 Hz), short switch pierod (<200 ms) and high frequency stability as crystal oseillator.

BIT COMMITMENT USING PSEUDO-RANDOM SYNTHESIZER

This paper presents two practical message commitment schemes: one is suitable for committing many bits, and another is useful for committing any bit-long message. They are provably secure based on pseudo-random synthesizers. In these schemes, the sender may be unbounded to polynomial time and the receiver is bounded. The advantage of these schemes is that the secure parameter may be small.

KINETIC STUDY OF SPINEL LiMn_2O_4 SYNTHESIZED BY SOLID REACTION WITH SOFT-CHEMICAL METHOD

The differential thermal analysis （DTA） curves were measured at different heating rates in flowing air for studying the synthesis of the spinel LiMn2O3 with Li2CO3 and MnO2, The reaction began at about 503K, and finished at about 873K. The apparent activation energy of Kissinger method was about 122.77kJ.mol^-1, the reaction orderwas 1.67, the frequency factor was 7.81×10^9, and therefore the dinetic epuation was dδ/dt=A·exp（- E/RT）·（1-δ）^n=7.81×10^9, exp（-122770/RT）·（l-δ）^1.67 . Coats-Redfem integral method was used to analyze the DTA curves of the samples at different heating rates, and the calculated apparent activation energy and frequency factor were 112. 13kJ· mol^-1 and 1.18 × 10^9, respectively, rather close to that of Kissinger method. X-ray diffraction （XRD） and scanning electron microscope （SEM） results shown that the synthesized LiMn2O3 possesses pure phase, regular shape and normal particle distribution.

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℃ respectively

Thermal Characteristics of PVA-PANI-ZnS Nanocomposite Film Synthesized by Gamma Irradiation Method

Gamma irradiation is employed for in situ preparation of PVA-PANI-ZnS nanocomposite. The irradiation dose is varied from 10 to 40 kGy at 10 kGy intervals. The XRD result confirms the formation of crystalline phases corresponding to ZnS nanoparticles, PVA and PANI. Field emission scanning electron microscopy shows the formation of agglomerated PANI along the PVA backbone, within which the ZnS nanoparticles are dispersed.UV-visible spectroscopy is conducted to measure the transmittance spectra of samples revealing the electronic absorption characteristics of ZnS and PANI nanoparticles. Photo-acoustic（PA） setup is installed to investigate the thermal properties of samples. The PA spectroscopy indicates a high value of thermal diffusivity for samples due to the presence of ZnS and PANI nanoparticles. Moreover, at higher doses, the more polymerization and formation of PANI and ZnS nanoparticles result in enhancement of thermal diffusivity.