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A series of copolymers were synthesized by the ring-opening bulk polymerization of e-caprolactone (CL) and 2-phenyl-5,5-bis(hydroxymethyl) trimethylene carbonate (PTC) with tin(II) 2-ethylhexanoate as a catalyst. These copolymers were further reduced with a palladium/carbonate catalyst to obtain partly deprotected copolymers. The two types of copolymers that were obtained were characterized with 1H-NMR, Fourier transform infrared spectroscopy, UV, gel permeation chromatography, differential scanning calorimetry, and automatic contact-angle measurements. The influences of the monomer feed molar ratio, catalyst concentration, and reaction time as well as the reaction temperature on the copolymerization process were also studied. The copolymerization of CL and PTC monomers was a nonideal copolymerization, and the copolymerization reactivity ratio of CL was higher than that of PTC in the polymerization process. In vitro degradation tests indicated that the partly deprotected copolymers possessed faster degradation rates and greater hydrophilicity than the unreduced copolymers. In vitro release profiles of fluorouracil from the copolymers showed that these two types of copolymers had steady drug-release rates and good controlled-release properties. Moreover, the partly deprotected copolymers had faster drug-release rates than the unreduced copolymers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Reactions of O2 with the four-membered cyclic complexes {(Me2N)[(Me3Si)2N]M[N(SiMe3)SiMe2CH2]}2 (M = Zr (1a), Hf (1b)), containing both M−C and M−N bonds, give the five-membered cyclic complexes {(Me2N)[(Me3Si)2N]M[N(SiMe3)SiMe2CH2O]}2 (M = Zr (2a), Hf (2b)) with rarely observed selective O insertion into the M−C bonds. Both dimeric products exist as interesting cis and trans isomers.

A series of polycarbonate copolymers were synthesized by microwave-assisted ring-opening polymerization of ɛ-caprolactone (CL) and 2-phenyl-5,5-bis(oxymethyl) trimethylene carbonate (PTC) with Tin (II) 2-ethylhexanoate as a catalyst. These copolymers obtained were detected by 1H NMR, FT-IR, UV, gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and automatic contact angle meter. The influences of the feed molar ratio of monomers, catalyst concentration, reaction time and reaction temperature, as well as microwave irradiation power on the copolymerization process were also studied. In vitro degradation tests indicated that these polycarbonate copolymers possess the slow degradation rates and strong hydrophobicity. In vitro release profiles of 5-Fu from copolymers showed that copolymers have the steady drug release rates and good controlled release properties.

Group 4 amide chloride complexes (Me2N)2Hf[N(SiMe3)2]Cl (1b), [(Me3Si)2N]2MCl2Li(THF)3Cl (M = Zr, 2a; Hf, 2b), and [(Me3Si)2N]2MCl2(THF) (M = Zr, 3a; Hf, 3b) and their X-ray crystal structures are reported. An improved synthesis of {[(Me3Si)2N]Ti(μ-NSiMe3)Cl}2 (4) and its use to prepare amide imide {[(Me3Si)2N]Ti(μ-NSiMe3)(NMe2)}2 (5) are also presented. X-ray crystal structures of 5 and previously reported complexes (Me2N)2Zr[N(SiMe3)2]Cl (1a), [(Me3Si)2N]2TiCl2 (6), and [(Me3Si)2N]ZrCl3(THF)2 (7) have been determined. Both 1a and 1b are dimers {[(Me3Si)2N]-(Me2N)2M(μ-Cl)}2 (M = Zr, Hf) in the solid state.

Surface-initiated atom-transfer radical polymerization (ATRP) of 4-vinylpyridine (4VP) on a pretreated Si(100) surface was carried out. The composition and topography of the Si(100) surface modified by poly(4-vinylpyridine) (P4VP) were characterized by XPS and atomic force microscopy (AFM), respectively. The P4VP layer on the Si(100) surface was used not only as chemisorption sites for the palladium complexes without prior sensitization by SnCl2 solution during the electroless plating, but also as an adhesion promotion layer for the electrolessly deposited copper. The electrolessly deposited copper on the Si–P4VP surface exhibited a 180° peel adhesion strength above 6 N/cm. The adhesion strength was much higher than that of the electrolessly deposited copper to the pristine silicon surface. Copyright © 2008 John Wiley & Sons, Ltd.

Lanthanide-organic complexes of the general type Ln[N(SiMe(3))(2)](3) (Ln = La, Sm, Y, Lu) serve as effective precatalysts for the rapid, exoselective, and highly regioselective intramolecular hydroalkoxylation/cyclization of primary and secondary alkynyl alcohols to yield the corresponding exocyclic enol ethers. Conversions are highly selective with products distinctly different from those generally produced by conventional transition metal catalysts, and turnover frequencies as high as 52.8 h(-1) at 25 degrees C are observed. The rates of terminal alkynl alcohol hydroalkoxylation/cyclization are significantly more rapid than those of internal alkynyl alcohols, arguing that steric demands dominate the cyclization transition state. The hydroalkoxylation/cyclization of internal alkynyl alcohols affords excellent E-selectivity. The hydroalkoxylation/cyclization of the SiMe(3)-terminated internal alkynyl alcohols reveals interesting product profiles which include the desired exocyclic ether, a SiMe(3)-eliminated exocyclic ether, and the SiMe(3)-O-functionalized substrate. The rate law for alkynyl alcohol hydroalkoxylation/cyclization is first-order in [catalyst] and zero-order in [alkynyl alcohol], as observed in the intramolecular hydroamination/cyclization of aminoalkenes, aminoalkynes, and aminoallenes. An ROH/ROD kinetic isotope effect of 0.95(0.03) is observed for hydroalkoxylation/cyclization. These mechanistic data implicate turnover-limiting insertion of C-C unsaturation into the Ln-O bond, involving a highly organized transition state, with subsequent, rapid Ln-C protonolysis.

Polyaniline–palladium (PANi-Pd) composite microflakes were synthesized through an immiscible organic/inorganic biphasic system in the presence of poly(ethylene glycol) with molecular weight 4,000 (PEG4000). Aniline was oxidized by PdCl2 in the interface polymerization system, yielding PANi microflakes and elemental Pd nanoparticles simultaneously. Palladium nanoparticles were uniformly dispersed in the microflakes of PANi. The results of FTIR spectra suggested that the oxidation degree of PANi was affected by the initial ratio of metal ions to monomer. The PANi-Pd composites were characterized using X-ray photoelectron spectroscopy and the conductivity of the composite was measured by conventional four-probe method. Scanning and transmission electron microscopy were used to show the morphology of the composites.

Poly(ether imide) (PEI) was chloromethylated by a simple one-step method under mild conditions to provide surface benzyl chloride groups as the active initiators for the surface-initiated atom-transfer radical polymerization (ATRP). Functional hydrophilic polymer brushes of poly(ethylene glycol) monomethacrylate and sodium 4-styrenesulfonate, as well as their block copolymer brushes, were synthesized via surface-initiated ATRP from the chloromethylated PEI membrane surfaces. The surface-modified membranes were studied by X-ray photoelectron spectroscopy. Using the bovine serum albumin solution adsorption test, the grafted PEI membranes showed great antifouling properties compared to the pristine PEI surface. Thus, the chloromethylated PEI membranes with the active ATRP initiators opens up opportunities for the functionalization of membranes via surface molecular design.

Surface modification of polyimide (PI) films were first carried out by chloromethylation under mild conditions, followed by surface-initiated atom-transfer radical polymerization (ATRP) of 4-vinylpyridine (4VP) from the chloromethylated PI surfaces. The composition and topography of the PI surfaces modified by poly(4-vinylpyridine) (P4VP) were characterized by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM), respectively. The P4VP brushes with well-preserved pyridine groups on the PI surface was used not only as the chemisorption sites for the palladium complexes without prior sensitization by SnCl 2 solution during the electroless plating of copper, but also as an adhesion promotion layer to enhance the adhesion of the electrolessly deposited copper to the PI surfaces. The T-peel adhesion strength of the electrolessly deposited copper on the modified PI surface could reach about 6.6 N/cm. Effects of the polymerization time and the activation time in the PdCl 2 solution on the T-peel adhesion strength of the electrolessly deposited copper in the Sn-free process to the modified PI surface were also studied.

Reactions of MCl5 (M = Nb, Ta) with LiNMe2 have been found to yield M(NMe2)4(η2-MeNCH2NMe2) (M = Nb, 2a; Ta, 2b) containing a chelating ligand (dimethylaminomethylene)methylamide, as confirmed by NMR spectroscopy, DFT calculations, and their reactivity studies.

A series of polycarbonate copolymers were synthesized by the ring-opening bulk polymerization of 2-phenyl-5,5-bis(hydroxymethyl) trimethylene carbonate (PTC) and 5,5-dimethyl trimethylene carbonate (DTC) with tin(II) 2-ethylhexanoate and aluminum isopropoxide as initiators. The copolymers obtained were characterized by 1 H-NMR, Fourier transform infrared, and ultraviolet. The influence of the molar ratio of the monomers, the initiators, and their concentrations, the reaction time, and the reaction temperature on the copolymerization was also studied. The copolymerization of monomers DTC and PTC was a nonideal copolymerization, and the copolymerization reactivity ratio of the monomer DTC was higher than that of PTC in the copolymerization process. In vitro release profiles of fluorouracil from the copolymers showed that the copolymer had a steady drug-release rate and good controlled-release property.

Reaction of d0 Ta(NMe2)5 (1) with O2 yields two aminoxy complexes (Me2N)(n)Ta(eta2-ONMe2)(5-n) (n = 4, 2; 3, 3) as well as (Me2N)4Ta2[eta2-N(Me)CH2NMe2]2(mu-O)2 (4) and (Me2N)6Ta3[eta2-N(Me)CH2NMe2]2(eta2-ONMe2)(mu-O)3 (5) containing novel chelating (aminomethyl)amide-N(Me)CH2NMe2 ligands. The crystal structures of 2-5 have been determined by X-ray crystallography. (Me2N)4Ta(eta2-ONMe2) (2) converts to (Me2N)3Ta(eta2-ONMe2)2 (3) in its reaction with O2. In addition, the reaction of Ta(NMe2)5 with 3 gives 2 only at elevated temperatures. Density functional theory (DFT) calculations have been used to investigate the mechanistic pathways in the reactions of Ta(NMe2)5 (1) with triplet O2. Monomeric reaction pathways in the formation of 2-5 are proposed. A key step is the oxygen insertion into a Ta-N bond in 1 through an intersystem conversion from triplet to singlet energy surface to give an active peroxide complex (Me2N)4Ta(eta2-O-O-NMe2) (A4). The DFT studies indicate that the peroxide ligand plays an important role, including oxidizing an amide to an imine ligand through the abstraction of a hydride. Insertion of Me-N=CH2 into a Ta-amide bond yields the unusual -N(Me)CH2NMe2 ligands.

In merits of super-resolved resolution and fast speed of three-dimensional (3D) optical sectioning capability, structured illumination microscopy (SIM) has found variety of applications in biomedical imaging. So far, most SIM systems use monochrome CCD or CMOS cameras to acquire images and discard the natural color information of the specimens. Although multicolor integration scheme are employed, multiple excitation sources and detectors are required and the spectral information is limited to a few of wavelengths. Here, we report a new method for full-color SIM with a color digital camera. A data processing algorithm based on HSV (Hue, Saturation and Value) color space is proposed, in which the recorded color raw images are processed in the Hue, Saturation, Value color channels and then reconstructed to a 3D image with full color. We demonstrated some 3D optical sectioning results on samples such as mixed pollen grains, insects, micro-chips and the surface of coins. The presented technique is applicable to some circumstance where color information plays crucial roles, such as in materials science and surface morphology.

Preparation and characterization of novel alkyl alkylidyne (Me3SiCH2)3W(⋮CSiMe3)(PMe3) (1a) and bis-alkylidene (Me3SiCH2)2W(CHSiMe3)2(PMe3) (1b) and studies of the exchange between alkylidyne 1a an...

Cyclopentadienyl-free disilyl amide complexes [(Me2N)3M(SiButPh2)2]- (M = Zr, 1; Hf, 2 as [Li(THF)4]+ salts), K(18-crown-6)3/2{(Me2N)3M[(Me3Si)2Si-(CH2)2-Si(SiMe3)2]} (M = Zr, 3; Hf, 4), (Me2N)3Ta[Si(SiMe3)3]2 (5), (Me2N)3Ta(SiButPh2)2 (6), and (Me2N)3Ta(SiButPh2)[Si(SiMe3)3] (7) have been prepared. The structures of 1−4 have been determined by X-ray single-crystal diffraction. The two −Si(SiMe3)3- ligands in (Me2N)3Ta[Si(SiMe3)3]2 (5) were replaced sequentially by the −SiButPh2- anions to give (Me2N)3Ta(SiButPh2)[Si(SiMe3)3] (7) and (Me2N)3Ta(SiButPh2)2 (6). The silyl ligand in (Me2N)3Zr-Si(SiMe3)3 was found to undergo a reversible exchange with SiButPh2-, probably through a disilyl intermediate, to reach the following equilibrium: (Me2N)3ZrSi(SiMe3)3 + SiButPh2- ⇌ (Me2N)3ZrSiButPh2 + Si(SiMe3)3- with ΔH° = 4.6(0.5) kcal/mol and ΔS° = −7(2) eu. A similar exchange involving [(Me2N)3M(SiButPh2)2]- (M = Zr, 1; Hf, 2) was observed: (Me2N)3ZrSiButPh2 + SiButPh2- ⇌ 1 with the estimated free energy of activat...

Reactions of d0 amides M(NMe2)4 (M = Zr, 1; Hf, 2) with O2 have been found to yield unusual trinuclear oxo aminoxide complexes M3(NMe2)6(mu-NMe2)3(mu3-O)(mu3-ONMe2) (M = Zr, 3; Hf, 4) in high yields. Tetramethylhydrazine Me2N-NMe2 was also observed in the reaction mixtures. Crystal structures of 3 and 4 have been determined. Density functional theory calculations have been performed to explore the mechanistic pathways in the reactions of model complexes Zr(NR2)4 (R = H, 5; Me, 1) and [Zr(NR2)4]2 (R = H, 5a; Me, 1a) with triplet O2. Monomeric and dimeric reaction pathways in the formation of the Zr complex 3 are proposed.

Ammonolysis of previously reported Cl-M[N(SiMe3)2]3 (M = Zr, 1a; Hf, 1b) leads to the formation of peramides H2N-M[N(SiMe3)2]3 (M = Zr, 2a; Hf, 2b) which upon deprotonation by LiN(SiMe3)2 or Li(THF)3SiPh2But yields imides Li+(THF)n{HN(-)-M[N(SiMe3)2]3} (M = Zr, 3a; Hf, 3b). One -SiMe3 group in 3a-b undergoes silyl migration from a -N(SiMe3)2 ligand to the imide =NH ligand to give Li+(THF)2{Me3SiN(-)-M[NH(SiMe3)][N(SiMe3)2]2} (M = Zr, 4a; Hf, 4b) containing an imide =N(SiMe3) ligand. The kinetics of the 3a --4a conversion was investigated between 290 and 315 K and was first-order with respect to 3a. The activation parameters for this silyl migration are DeltaH++ = 13.3(1.3) kcal/mol and DeltaS++ = -34(3) eu in solutions of 3a (in toluene-d8 with 1.07 M THF) prepared in situ. THF in the mixed solvent promoted the 3a --4a reaction. The effect of THF on the rate constants of the conversion has been studied, and the kinetics of the reaction was 3.4(0.6)th order with respect to THF. Crystal and molecular structures of H2N-Zr[N(SiMe3)2]3 (2a) and 4a-b have been determined.

New transition metal silyl amide complexes (Me(2)N)(3)Ta[N(SiMe(3))(2)](SiPh(2)Bu(t)) (1) and (Me(2)N)M[N(SiMe(3))(2)](2)(SiPh(2)Bu(t)) (M = Zr, 2a, and Hf, 2b) were found to undergo gamma-H abstraction by the silyl ligands to give metallaheterocyclic complexes (3) and (M = Zr, 4a, and Hf, 4b), respectively. The conversion of 1 to 3 follows first-order kinetics with DeltaH() = 23.6(1.6) kcal/mol and DeltaS() = 3(5) eu between 288 and 313 K. The formation of 4a from (Me(2)N)Zr[N(SiMe(3))(2)](2)Cl (5a) and Li(THF)(2)SiPh(2)Bu(t) (6) involves the formation of the intermediate 2a, followed by gamma-H abstraction. Kinetic studies of these consecutive reactions, a second-order reaction to give 2a and then a first-order gamma-H abstraction to give 4a, were conducted by an analytical method and a numerical method. At 278 K, the rate constants k(1) and k(2) for the two consecutive reactions are 2.17(0.03) x 10(-)(3) M(-)(1) s(-)(1) and 5.80(0.15) x 10(-)(5) s(-)(1) by the analytical method. The current work is a rare kinetic study of the A + B --> C --> D (+ E) consecutive reactions. Kinetic studies of the formation of a metallaheterocyclic moiety have, to our knowledge, not been reported. In addition, gamma-H abstraction by a silyl ligand to give such a metallaheterocyclic moiety is new. Theoretical investigations of the gamma-H abstraction by silyl ligands have been conducted by density functional theory calculations at the Becke3LYP (B3LYP) level, and they revealed that the formation of the metallacyclic complexes through gamma-H abstraction is entropically driven. X-ray crystal structures of (Me(2)N)(3)Ta[N(SiMe(3))(2)](SiPh(2)Bu(t)) (1), (Me(2)N)Zr[N(SiMe(3))(2)](2)Cl (5a), and (M = Zr, 4a, and Hf, 4b) are also reported.

Studies from the authors' group of early-transition-metal silyl complexes and pathways in the reactions of silanes with transition-metal complexes are reviewed. Cyclopentadienyl-free, group 4 alkyl silyl, group 5 alkylidene silyl, group 6 alkylidyne silyl, and groups 4 and 5 amide and imide silyl complexes have been prepared and characterized. In the reactions of silanes with alkylidene and amide complexes, the MCH− π bonds and d−p π bonds in MNR2 were found to attack Si in silanes. The mechanistic studies here help in understanding the formation of mixtures of TiN and Si3N4 from the reactions of Ti(NMe2)4 and SiH4 as microelectronic diffusion barrier materials.

Reactions of Hg(II) salts with thioether carboxylic acids o -C 6 H 4 [CH(SCH 2 COOH) 2 ] 2 ( 1a ) and PhCH(SCH 2 COOH) 2 ( 3 ) in water were found to lead to the decomposition of these ligands with the formation of mercury(II) mercaptoacetate Hg(SCH 2 COOH) 2 ( 2 ) and aldehydes o -C 6 H 4 (CHO) 2 and PhCHO, respectively. A similar reaction was observed between Hg(NO 3 ) 2 and CH 3 (CH 2 ) 2 CH(SCH 2 COOH) 2 ( 4 ). The X-ray structure of Hg(SCH 2 COOH) 2 ( 2 ) shows a linear –S–Hg–S– moiety. The mechanism of the formation of 2 in the reactions between Hg 2+ and thioether carboxylic acids in water is discussed.

A new mixed-amido complex (Me2N)3Ta(Cl)[N(SiMe3)2] (1) was prepared from the reaction of (Me2N)3TaCl2 with 1 equiv. of LiN(SiMe3)2. The reactions of 1 with 1 equiv. of LiN(SiMe3)2 or (Me2N)3TaCl2 with 2 equiv. of LiN(SiMe3)2 gave (Me2N)3[Formula: see text] (2) with a four-membered metallaheterocyclic ring through γ-hydrogen abstraction. In the solid state, 1 adopts a distorted trigonal bipyramidal geometry with the -N(SiMe3)2 and -Cl ligands in the equatorial and axial positions, respectively. The X-ray structure of 2 reveals that it is in a distorted trigonal bipyramidal geometry with a planar metallaheterocyclic ring.Key words: tantalum, γ-hydrogen abstraction, C-H activation, amido complexes, metallacycle.

A solid-state reaction process has been developed to synthesize perovskite-type LaCoO 3 nanocrystals with grain diameters of 15-40 nm. In the first step of the preparation, ∼5 nm composite hydroxide nanoparticles are synthesized by the solid-state reaction of La(NO 3 ) 3 .nH 2 O and Co(NO 3 ) 2 .6H 2 O with KOH at ambient temperature. A perovskite-type rhombohedral LaCoO 3 phase appears at 550°C, after the hydroxide has been calcined at various temperatures. The phase transformation process is complete at ∼800°C, yielding a single-phase binary oxide. The results indicate that the new process is convenient, inexpensive, and effective for obtaining LaCoO 3 nanocrystals with high yield.

The synthesis and characterization of amido silyl complexes of tantalum(V) free of π-anionic ligands are reported. The amido silyl chloride complexes (Me2N)3Ta(SiR3)Cl [SiR3 = Si(SiMe3)3 (1a), SiPh2But (2)] were prepared from (Me2N)3TaCl2 and the corresponding silyllithium reagents Li(THF)3Si(SiMe3)3 and Li(THF)3SiPh2But. The amido silyl complexes (Me2N)4Ta(SiR3) [SiR3 = Si(SiMe3)3 (3), SiPh2But (4)] were synthesized by the reactions of (Me2N)4TaCl with Li(THF)3SiR3. Complex 3 was found to react with 1 equiv of O2 to give an oxidation product (Me2N)3Ta(η2-ONMe2)[OSi(SiMe3)3] (5), and the structure of 5 was confirmed by X-ray crystallography. The spectroscopic data and crystal structure determination reveal that the coordination geometry around Ta metal in 1a and 2−4 is trigonal bipyramid with silyl ligands in an equatorial position.

Low-refractive-index microparticles, such as hollow microspheres, have shown great significance in some applications, such as biomedical sensing and targeted drug delivery. However, optical trapping and manipulation of low-refractive-index microparticles are challenging, owing to the repelling force exerted by typical optical traps. In this paper, we demonstrated optical trapping and rotating of large-sized low-refractive-index microparticles by using quasi-perfect optical vortex (quasi-POV) beams, which were generated by Fourier transform of high-order quasi-Bessel beams. Numerical simulation was carried out to characterize the focusing property of the quasi-POV beams. The dynamics of low-refractive-index microparticles in the quasi-POV with various topological charges was investigated in detail. To improve the trapping and rotating performances of the vortex, a point trap was introduced at the center of the ring. Experimental results showed that the quasi-POV was preferable for manipulation of large-sized low-refractive-index microparticles, with its control of the particles' rotating velocity dependent only on the topological charge due to the unchanged orbital radius.

A new one-step solid-state reaction synthesis of tin oxide (SnO 2 ) nanoparticles has been developed. The process is a convenient, inexpensive and efficient preparation for SnO 2 nanomaterial with adjustable grain sizes in the range of 3–15 nm in high yield. They can be dispersed into EtOH or distilled water. The prepared SnO 2 nanoparticles have high sensitivities towards reducing gases.

Focusing and imaging through scattering media has been proved possible with high resolution wavefront shaping. A completely scrambled scattering field can be corrected by applying a correction phase mask on a phase only spatial light modulator (SLM) and thereby the focusing quality can be improved. The correction phase is often found by global searching algorithms, among which Genetic Algorithm (GA) stands out for its parallel optimization process and high performance in noisy environment. However, the convergence of GA slows down gradually with the progression of optimization, causing the improvement factor of optimization to reach a plateau eventually. In this report, we propose an interleaved segment correction (ISC) method that can significantly boost the improvement factor with the same number of iterations comparing with the conventional all segment correction (ASC) method. In the ISC method, all the phase segments are divided into a number of interleaved groups; GA optimization procedures are performed individually and sequentially among each group of segments. The final correction phase mask is formed by applying correction phases of all interleaved groups together on the SLM. The ISC method has been proved significantly useful in practice because of its ability to achieve better improvement factors when noise is present in the system. We have also demonstrated that the imaging quality is improved as better correction phases are found and applied on the SLM. Additionally, the ISC method lowers the demand of dynamic ranges of detection devices. The proposed method holds potential in applications, such as high-resolution imaging in deep tissue.

Remote-focusing microscopy has recently attracted a lot of interest due to its high-speed axial scanning capabilities. In this paper, we modeled remote-focusing microscopy, based on a pair of long working distance objective lenses. Three-dimensional intensity distributions of the point spread functions (PSFs) are calculated, and no significant spherical aberrations are introduced over a large volume of 100 μm×100 μm×150 μm. The validity of the scheme is verified by imaging biological samples and microelectronic chips at the imaging depth of 150 μm without introducing aberrations in the experiment.

A reflection mode digital holographic microscope with light emitting diode (LED) illumination and off-axis interferometry is proposed. The setup is comprised of a Linnik interferometer and a grating-based 4f imaging unit. Both object and reference waves travel coaxially and are split into multiple diffraction orders in the Fourier plane by the grating. The zeroth and first orders are filtered by a polarizing array to select orthogonally polarized object waves and reference waves. Subsequently, the object and reference waves are combined again in the output plane of the 4f system, and then the hologram with uniform contrast over the entire field of view can be acquired with the aid of a polarizer. The one-shot nature in the off-axis configuration enables an interferometric recording time on a millisecond scale. The validity of the proposed setup is illustrated by imaging nanostructured substrates, and the experimental results demonstrate that the phase noise is reduced drastically by an order of 68% when compared to a He–Ne laser-based result.

Polpyrrole (PPy)/silver nanocomposites with their size of around 80–120 nm were successfully synthesized at the interface of water and ionic liquid. High dispersed PPy/silver nanocomposites were obtained in the presence of polyvinylpyrrolidone (PVP) by controlling the reacting conditions. The morphology and structure of the resulting nanocomposites were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. It was also found that the electrical conductivity of PPy/silver nanocomposites was much higher than that of pure PPy. Cyclic voltammetric experiments further indicated that the nanocomposite had excellent redox ability: polypyrrole; silver; ionic liquid; interface synthesis; and nanocomposites.

Nano oxides (SiO2, CeO2, SnO2) were successfully synthesized by solid-state reactions at ambient temperature. The nanoparticles were characterized by X-ray powder diffraction, TEM, BET, and TGA-DTA. The SiO2 particles were also investigated using IR spectra. Effects of calcination on the nanoparticles were studied in this paper. The solid-state reaction technique is a convenient, inexpensive and an effective preparation method of monodisperse oxide nanoparticles in high yield. The mechanisms of the formation of nano materials by solid-state reactions at ambient temperature were primarily investigated.

The morphology and composition of the Ni–P–SiO 2 and Ni–P–CeO 2 electroless composite coatings were investigated by SEM, XPS, and AES. The surfaces of the coatings are homogeneous, polished, and with strong corrosion resistance. For the Ni–P–SiO 2 coating, the atomic percentages are Ni: 74.6%, P: 12.4%, Si: 2.77%, Fe: 2.32%, and O: 6.65%, and the compositions are Ni–P: 93.5%, SiO 2 : 3.27%, FeO: 1.56%, and Fe: 1.33%.

Polarization gratings can be recorded in bacteriorhodopsin films by an orthogonal pair of linearly or circularly polarized beams. If a linearly polarized auxiliary violet light is added during the grating formation, the grating becomes polarization-sensitive. A theoretical model based on the two-state photochromic theory is proposed to calculate the diffraction efficiency kinetics of these polarization gratings. In both cases, the additional linearly polarized auxiliary violet irradiation improves the steady-state diffraction efficiency and leads to a cosine modulation of the steady-state diffraction efficiency by the polarization orientation of the readout beam. Experiment results demonstrate the correctness of the theoretical model.

(Me3SiCH2)3(Me3SiC≡)W←O=PMe3 (1), an adduct between (Me3SiCH2)3W≡CSiMe3 (2) and O=PMe3, reacts with O2 to give O=W(OSiMe3)(CH2SiMe3)3 (3) and CO2. Reaction of 2 with H2O yields 3 and the trimer [(μ-O)W(CH2SiMe3)2(=O)(THF)]3 (4). In the reaction of D2O with 2, 3-d(n) and methane isotopologues CH2D2, CHD3 and CD4 have been observed.

The procedure provides products with olefinic positions which are different to those afforded by typical transition metal catalysts.

CeO2 ultrafine particles were prepared by solid-state reactions at room temperature. These particles were found to have very fine particle sizes (∼3 nm) with a fluorite structure (a= 5.42 A). BET measurements showed that the surface area of the particles was 96.2 m2/g. The use of two different precursors was found to affect the size of the CeO2 particles. We discuss the effect of calcination at different temperatures on the morphology, size, and BET surface area of CeO2 particles. A salt byproduct coating prevented agglomeration of the CeO2 particles.

The trisilyl dimeric zincate [K(18-crown-6)]2{[(Me3Si)2Si(CH2)2Si(SiMe3)2]2Zn2[μ-(Me3Si)2Si(CH2)2Si(SiMe3)2]} (1) is reported. In the structure of 1, each Zn center is bonded by one bridging disilyl ligand and one chelating disilyl ligand.

We propose a non-paraxial hollow accelerating beam, which is formed by incoherently superposing two well-designed coherent accelerating beams. Very interestingly, this incoherent superposition does not hamper the acceleration dynamics pertaining to the coherent ones, but results in a hollow intensity pattern in the cross section transverse to the circular accelerating trajectory. By a simple optimization, this hollow cross section pattern can be effectively extended to an angle close to 90°. The magnitude and the phase of the angular spectrum of the beam are given followed by a suggested scheme to generate the beam in practice. Such highly self-bending hollow beams may find applications in some fields such as optical manipulation.

Cylindrical vector (CV) beams have found increasing applications in physics, biology, and chemistry. To generate CV beams, interferometric technique is popularly adopted due to its flexibility. However, most interferometric configurations for the generation of CV beams are faced with system instability arising from external disturbance, limiting their practical applications. A common-path interferometer for the generation of radially and azimuthally polarized beams is proposed to improve the system stability. The optical configuration consists of a vortex phase plate acting to tailor the phase profile and a cube nonpolarizing beamsplitter to split the input beam into two components with mirror-like spiral phase distribution. The generated CV beams show a high quality in polarization and exhibit a better stability of beam profile than those obtained by noncommon-path interferometric configurations.

an improved and rapid three dimensional gerchberg-saxton (gs) algorithm based on the classic gs algorithm for computer generated holograms is proposed and applied to holographic optical tweezers. theoretical simulations and experimental results have demonstrated the rapidity and efficiency of the proposed algorithm. a robust holographic optical tweezers setup based on phase-only liquid-crystal spatial light modulator(slm) is built, and stable trapping and dynamic manipulation of yeast cells and silica beads with large array traps in three dimensions are demonstrated. two special traps, i.e., line trap with intensity gradient distribution and optical vortex trap, are generated to transport and rotate micro-particles respectively. the system is verified to be robust on particles manipulations, which provides a new and powerful tool for researches on biology, colloid physics and so on. © 2016, chinese laser press. all right reserved.

CeO2 ultrafine particles were prepared by solid-state reactions at room temperature. These particles were found to have very fine particle sizes (∼3 nm) with a fluorite structure (a= 5.42 A). BET measurements showed that the surface area of the particles was 96.2 m2/g. The use of two different precursors was found to affect the size of the CeO2 particles. We discuss the effect of calcination at different temperatures on the morphology, size, and BET surface area of CeO2 particles. A salt byproduct coating prevented agglomeration of the CeO2 particles.

A solid-state reaction process has been developed to synthesize perovskite-type LaCoO 3 nanocrystals with grain diameters of 15-40 nm. In the first step of the preparation, ∼5 nm composite hydroxide nanoparticles are synthesized by the solid-state reaction of La(NO 3 ) 3 .nH 2 O and Co(NO 3 ) 2 .6H 2 O with KOH at ambient temperature. A perovskite-type rhombohedral LaCoO 3 phase appears at 550°C, after the hydroxide has been calcined at various temperatures. The phase transformation process is complete at ∼800°C, yielding a single-phase binary oxide. The results indicate that the new process is convenient, inexpensive, and effective for obtaining LaCoO 3 nanocrystals with high yield.

Low generational polyamidoamine (PAMAM) dendrimers with triethylene glycol (TEG) core and ester groups at the surface have been synthesized and investigated as templates for preparation of gold nanoparticles (AuNPs), by reducing chloroauric acid (HAuCl4) with potassium borohydride (KBH4) in N,N-dimethylformamide (DMF). UV-vis absorption spectroscopy, fourier transform infrared (FT-IR) spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM) were used to confirm the formation of AuNPs. Stable gold nanoparticles with particle size around 10 nm were obtained and the interaction between the dendrimers and Au moieties is discussed.

The reaction of Nb(NMe(2))(5) with O(2) gives three complexes: monomeric (Me(2)N)(n)Nb(eta(2)-ONMe(2))(5-n) (n = 3, 4) and dimeric (Me(2)N)(4)Nb(2)[eta(2)-N(Me)CH(2)NMe(2)](2)(mu-O)(2). Nb(NEt(2))(5) was prepared in a mixture of pentane and THF, leading to its purification and characterization by single-crystal X-ray diffraction. Unlike Nb(NMe(2))(5), which adopts a square pyramidal structure, Nb(NEt(2))(5) is a distorted trigonal bipyramid. The reaction of Nb(NEt(2))(5) with O(2) gives an insoluble white solid.

A simple one-step method for the chloromethylation of polyethersulfone (PES) under mild conditions provided surface benzyl chloride groups as the active initiators for the surface-initiated atom-transfer radical polymerization (ATRP) to tailor the functionality of the PES membrane. Functional hydrophilic polymer brushes of poly(ethylene glycol)monomethacrylate (PEGMA) and sodium 4- styrenesulfonate (NaStS), as well as their block copolymer brushes, were prepared via surface initiated ATRP from the chloromethylated PES surfaces. X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were used to characterize the surface-modified membranes. The PEGMA-grafted PES membranes showed great protein resistance to protein adsorption compared to the pristine PES surface.