Volume Comparison of Conformally Compact Manifolds with Scalar Curvature <Emphasis Type="Italic">R</Emphasis> ≥ −<Emphasis Type="Italic">n</Emphasis> (<Emphasis Type="Italic">n</Emphasis> − 1)

In this paper, we use the normalized Ricci–DeTurk flow to prove a stability result for strictly stable conformally compact Einstein manifolds. As an application, we show a local volume comparison of conformally compact manifolds with scalar curvature R ≥ ?n (n ? 1) and also the rigidity result when certain relative volume is zero.     

Tightness and Convergence of Trimmed Lévy Processes to Normality at Small Times

For nonnegative integers r, s, let \(^{(r,s)}X_t\) be the Lévy process \(X_t\) with the r largest positive jumps and the s smallest negative jumps up till time t deleted, and let \(^{(r)}\widetilde{X}_t\) be \(X_t\) with the r largest jumps in modulus up till time t deleted. Let \(a_t \in \mathbb {R}\) and \(b_t>0\) be non-stochastic functions in t. We show that the tightness of \(({}^{(r,s)}X_t - a_t)/b_t\) or \(({}^{(r)}{\widetilde{X}}_t - a_t)/b_t\) as \(t\downarrow 0\) implies the tightness of all normed ordered jumps, and hence the tightness of the untrimmed process \((X_t -a_t)/b_t\) at 0. We use this to deduce that the trimmed process \(({}^{(r,s)}X_t - a_t)/b_t\) or \(({}^{(r)}{\widetilde{X}}_t - a_t)/b_t\) converges to N(0, 1) or to a degenerate distribution as \(t\downarrow 0\) if and only if \((X_t-a_t)/b_t \) converges to N(0, 1) or to the same degenerate distribution, as \(t \downarrow 0\).     

π‐Conjugated Microporous Polymer Films: Designed Synthesis,Conducting Properties,and Photoenergy Conversions

Conjugated microporous polymers are a unique class of polymers that combine extended π‐conjugation with inherent porosity. However, these polymers are synthesized through solution‐phase reactions to yield insoluble and unprocessable solids, which preclude not only the evaluation of their conducting properties but also the fabrication of thin films for device implementation. Here, we report a strategy for the synthesis of thin films of π‐conjugated microporous polymers by designing thiophene‐based electropolymerization at the solution–electrode interface. High‐quality films are prepared on a large area of various electrodes, the film thickness is controllable, and the films are used for device fabrication. These films are outstanding hole conductors and, upon incorporation of fullerenes into the pores, function as highly efficient photoactive layers for energy conversions. Our film strategy may boost the applications in photocatalysis, energy storage, and optoelectronics.     

Artificial luminescent protein as a bioprobe for time-gated luminescence bioimaging

An artificial luminescent protein, apoferritin-encapsulated luminescent europium complex, has been designed/fabricated and displays good biocompatibility and long-lived luminescence, which means it can be used as a bioprobe to image living cells with a time-gated mode.     

Tantalum compounds as heterogeneous catalysts for saccharide dehydration to 5-hydroxymethylfurfural

A new solid acid, based on tantalum hydroxide, was used to catalyze saccharide dehydration into 5-hydroxymethylfurfural (HMF) with high catalytic activity and excellent stability in a water-2-butanol biphasic system. Furthermore, good results were also obtained from Jerusalem artichoke juice with the catalyst under the same conditions.     

P-T stability conditions of methane hydrate in sediment from South China Sea

For reasonable assessment and safe exploitation of marine gas hydrate resource, it is important to determine the stability conditions of gas hydrates in marine sediment. In this paper, the seafloor water sample and sediment sample (saturated with pore water) from Shenhu Area of South China Sea were used to synthesize methane hydrates, and the stability conditions of methane hydrates were investigated by multi-step heating dissociation method. Preliminary experimental results show that the dissociation temperature of methane hydrate both in seafloor water and marine sediment, under any given pressure, is depressed by approximately -1.4 K relative to the pure water system. This phenomenon indicates that hydrate stability in marine sediment is mainly affected by pore water ions.     

Effect of composite supports on the methanation activity of Co-Mo-based sulphur-resistant catalysts

The effects of composite supports of CeO2-Al2O3,MgO-Al2O3,TiO2-Al2O3 or ZrO2-Al2O3 on the methanation activity of supported Co-Mo-based sulphur-resistant catalysts were investigated.The catalysts were further characterized by nitrogen adsorption measurement,X-ray diffraction and X-ray photoelectron spectroscopy.The catalyst of 5%CoO-15%MoO3 supported on CeO2-Al2O3,MgO-Al2O3,TiO2-Al2O3 or ZrO2-Al2O3 composite oxides,respectively,showed different catalytic performances of syngas methanation in the presence of hydrogen sulphide as compared with that of the 5%CoO-15%MoO3/Al2O3 catalyst.The Co-Mo/CeO2-Al2O3 catalyst shows the highest methanation activity among the tested catalysts.The enhanced methanation activity may be attributed to the improvement of the dispersion of active metal species and the inhibition of the formation of S6+.     

The Kinetics of the Coordination Transformation for Preparation of Nanosized CdS in a PVA Film

Research on the preparation kinetics of nanosized materials is considered. The layered diffusion model (LDM) for S^2? diffusing in a polymer–metal complex film, used for preparation of nanosized semiconductor metal sulfide by a coordination transformation method, is briefly introduced. An indirect measurement was employed to determine the concentration of residual S^2? in the solution during the diffusion in a PVA–Cd²⁺ complex film. The relationship between the diffusion amount and the diffusion time shows that the diffusion curves are independent of the amount of Cd²⁺ in the film when the total amount of S^2? is less than that of Cd²⁺. The experimental phenomena coincide basically with the theoretical curves deduced from LDM; thus they provide a proof for the LDM and the diffusion equations. The diffusion constant of S^2? diffusing in PVA–Cd²⁺ complex film is about 1.7×10^?3 cm²/s.     

Measurement of oligochitosan-tobacco cell interaction by fluorometric method using europium complexes as fluorescence probes

The interaction of oligochitosan and tobacco cells has been investigated by fluorometric method using two Eu³⁺ complexes as the probes in this work. Based on the reaction of tobacco cells with oligochitosan conjugated to a strongly fluorescent Eu³⁺ complex 4,4′-bis(1″,1″,1″,2″,2″,3″,3″-heptafluoro-4″,6″-hexanedion-6″-yl)chlorosulfo-o-terphenyl-Eu³⁺ (oligochitosan-BHHCT-Eu³⁺ conjugate), the binding kinetic process of oligochitosan-tobacco cells was fluorescently imaged. The results indicate that oligochitosan can be specifically bound to the walls as well as the membranes of tobacco cells. A sensitive and selective Eu³⁺ complex luminescence probe specific for singlet oxygen, [4′-(10-methyl-9-anthryl)-2,2′:6′,2″-terpyridine-6,6″-diyl]bis(methylenenitrilo)tetrakis (acetate)-Eu³⁺, was used for developing a new time-resolved fluorescence assay method for the determinations of indole-3-acetic acid (IAA) and peroxidase produced in the cells during the interaction of oligochitosan and tobacco cells. The assays are sensitive with the detection limits of 32 nM for IAA, and 1.2 nM for peroxidase, respectively. The concentration changes of IAA and peroxidase induced by oligochitosan in tobacco cells reveal that oligochitosan can effectively induce the increase of IAA concentration, accompanied by the decrease of peroxidase concentration. These results give a primary and reliable evidence to explain the growth-promoting mechanism of oligochitosan on the plants at molecular level.