Showing papers by "Xuzhou Institute of Technology published in 2015"
TL;DR: By selecting 3-methyl-2-vinylindoles as a class of competent dienophiles, this approach provides an efficient strategy to construct an enantioenriched chroman framework with three adjacent stereogenic centers in high yields and excellent stereoselectivities.
Abstract: The first catalytic asymmetric inverse-electron-demand (IED) oxa-Diels–Alder reaction of ortho-quinone methides, generated in situ from ortho-hydroxybenzyl alcohols, has been established. By selecting 3-methyl-2-vinylindoles as a class of competent dienophiles, this approach provides an efficient strategy to construct an enantioenriched chroman framework with three adjacent stereogenic centers in high yields and excellent stereoselectivities (up to 99 % yield, >95:5 d.r., 99.5:0.5 e.r.). The utilization of ortho-hydroxybenzyl alcohols as precursors of dienes and 3-methyl-2-vinylindoles as dienophiles, as well as the hydrogen-bonding activation mode of the substrates met the challenges of a catalytic asymmetric IED oxa-Diels–Alder reaction.
273 citations
TL;DR: The first catalytic enantioselective construction of a 3,3'-pyrrolidinyldispirooxindole scaffold has been established via organocatalytic asymmetric 1,3-dipolar cycloadditions of isatin-derived azomethine ylides with methyleneindolinones.
Abstract: The first catalytic enantioselective construction of a 3,3′-pyrrolidinyldispirooxindole scaffold has been established via organocatalytic asymmetric 1,3-dipolar cycloadditions of isatin-derived azomethine ylides with methyleneindolinones, which afforded structurally complex bis-spirooxindoles containing three contiguous and two quaternary stereogenic centers in generally high yields (up to 99%) and excellent diastereo- and enantioselectivities (up to >95:5 dr, 98% ee). This reaction also provides a good example for the application of catalytic asymmetric 1,3-dipolar cycloadditions in constructing enantioenriched bis-spirooxindole frameworks with structural complexity and rigidity.
158 citations
TL;DR: In this paper, the effect of high pressure processing (HPP) at different pressures and treatment times on microbial population, physicochemical parameters, bioactive compounds, total antioxidant activity and volatile compounds in green asparagus juice, in comparison with thermal processing (121°C/3 min) and control (no treatment).
Abstract: This study was conducted to investigate the effect of high pressure processing (HPP) at different pressures (200, 400 and 600 MPa) and treatment times (10 and 20 min) on microbial population, physicochemical parameters, bioactive compounds, total antioxidant activity and volatile compounds in green asparagus juice, in comparison with thermal processing (121 °C/3 min) and control (no treatment). The results indicated that HPP at 400 and 600 MPa for both treatment times decreased the total mesophilic bacteria to undetectable level as the thermal treatment did, thus ensuring the safety of asparagus juice. The pH value and soluble solids content of asparagus juice were not significantly affected by HPP treatments as compared to thermal processing and control. However, all HPP treatments retained significantly more ascorbic acid, rutin and total phenolic contents and higher total antioxidant activity than thermal treatment. The main volatile compounds in asparagus juice were aldehydes, alcohols and ketones. HPP treatments maintained significantly higher concentrations of aldehydes, alcohols and ketones than thermal treatment. These results suggest that HPP could be an effective alternative to conventional thermal processing for production of high quality green asparagus juice.
76 citations
TL;DR: The rheological, emulsification, thermostability and certain physicochemical properties of two purified exopolysaccharides from Bacillus amyloliquefaciens LPL061 were studied and EPS1 is the most promising one for applications in the industry, as it had high intrinsic viscosity, apparent Viscosity and thermostablity in aqueous solution, dense entangled structure and good emulsion activity.
68 citations
TL;DR: Findings indicate that TOP-2 exert antitumor activity in vivo potentially by improving immune function and could be empoldered as a potential supplementary agent for cancer treatment.
54 citations
TL;DR: In this paper, the effect of aluminum concentration on the microstructure, wettability, interfacial IMC and mechanical properties of Sn 0.7Cu lead-free solder alloy is investigated.
51 citations
TL;DR: In this article, the authors focused on the interaction between maintenance, buffer inventory, and spare parts inventory, to achieve the minimization of the long-term expected cost rate for a production system.
36 citations
TL;DR: A chiral phosphoric acid-catalyzed asymmetric reaction of 2-indolylmethanols with 3-alkylindoles has been established, which constructed a biologically important 2,2'-bisindolymethane scaffold in high yields and good enantioselectivities.
Abstract: A chiral phosphoric acid-catalyzed asymmetric reaction of 2-indolylmethanols with 3-alkylindoles has been established, which constructed a biologically important 2,2′-bisindolylmethane scaffold in high yields and good enantioselectivities (up to 98% yield, 94 : 6 er). This protocol not only provides an efficient method for constructing a 2,2′-bisindolylmethane framework in an enantioselective form, but also promotes the development of 2-indolylmethanol-involved catalytic asymmetric transformations.
35 citations
TL;DR: In this article, the authors characterize the boundedness and compactness of linear operators induced by products of these operators from logarithmic Bloch spaces to weighted-type spaces on the unit ball.
34 citations
02 Aug 2015
TL;DR: This paper analyzes the role of big data in supply chains and presents a novel framework of a supply chain risk management system for improving supply chain planning and supply network risk management under stochastic environments by using big data technologies and analytics.
Abstract: The trend of big data implies novel opportunities and challenges for improving supply chain management. In particular, supply chain risk management can largely benefit from big data technologies and analytic methods for collecting, analyzing, and monitoring both supply chain internal data and environmental data. Due to the increasing complexity, particular attention must not only be put on the processing and analysis of data, but also on the interaction between big data information systems and users. In this paper, we analyze the role of big data in supply chains and present a novel framework of a supply chain risk management system for improving supply chain planning and supply chain risk management under stochastic environments by using big data technologies and analytics. The process-oriented framework serves as a guideline to integrate and analyze big data as well as to implement a respective supply chain risk management system. As such, this paper provides a novel direction of utilizing big data in supply chain risk management.
34 citations
TL;DR: A novel strain of DPAB is described and the optimal conditions for nitrogen and phosphorus removal by this strain are described, and the denitrification rate was 89.96%.
TL;DR: In this paper, the authors derived an expression to describe the droplet size distribution, which is a function of the surface fraction, fractal dimension, and the maximum radius of droplets.
TL;DR: In this article, the authors investigated the behaviors of particle migration within fractures of coalbed methane (CBM) reservoirs using laboratory simulation technology, and a mathematical model was built to calculate the maximum water production of a CBM well that can be tolerated without damage to the reservoir.
TL;DR: In this article, the uniaxial compression tests for mudstone specimens are carried out with four different loading rates from room temperature to 400°C by using the Rock Mechanics Servo-controlled Testing System MTS810 and high temperature furnace MTS652.
Abstract: The uniaxial compression tests for mudstone specimens are carried out with four different loading rates from room temperature to 400 °C by using the Rock Mechanics Servo-controlled Testing System MTS810 and high temperature furnace MTS652.02. The mechanical properties of mudstone with various loading rates are studied under different temperature conditions. The results show that when temperature increases from room temperature to 400 °C and loading rate is less than 0.03 mm/s, the peak strength of mudstone specimen decreases as loading rate increases, while the various peak strengths show significant differences when loading rate exceeds 0.03 mm/s. At room temperature, the elastic modulus decreases at the first time and then increases with loading rate rising. When the temperature is between 200 and 400 °C, the elastic modulus presents a decreasing trend with increasing loading rate. With increasing the loading rate, the number of fragments in mudstone becomes larger and even the powder is observed in mudstone with higher loading rate. Under high loading rate, the failure mode of mudstone specimens under different temperatures is mainly conical damage.
TL;DR: In this paper, the effect of BaTiO3 nanoparticles on the microstructure, wettability, and mechanical properties of Sn-58Bi solder has been investigated, and the results show that the micro-structure of the Sn-Bi-x wt.%BaTiOO3 (x = 0.5, 1, 2, 3) composite solders is refined and homogeneous due to increasing heterogeneous nucleation sites in the solder matrix.
Abstract: The effect of BaTiO3 nanoparticles on the microstructure, wettability, and mechanical properties of Sn-58Bi solder has been investigated. The results show that the microstructure of the Sn-58Bi-x wt.%BaTiO3 (x = 0.5, 1, 2, 3) composite solders is refined and homogeneous due to increasing heterogeneous nucleation sites of BaTiO3 nanoparticles in the solder matrix. The best wettability with spreading coefficient of 0.86 was obtained for Sn-Bi-1 wt.%BaTiO3, increased by 10.24% compared with Sn-58Bi solder. High mechanical properties were achieved for Sn-58Bi solder with small addition (0.5 wt.% to 3 wt.%) of BaTiO3. The ultimate tensile strength (UTS) of Sn-58Bi is 44.7 MPa, and that of Sn-Bi-1%BaTiO3 is 59.1 MPa. Fracture surface analysis indicated that the microscopic fracture of Sn-Bi-1%BaTiO3 solder is composed of tearing marks and ductility is improved. Therefore, Sn-Bi-1%BaTiO3 composite solder is one of the candidates for packaging and interconnection applications.
TL;DR: The results show that the microstructure of Sn–Cu–Al solder alloy is refined by Al, and the superior mechanical properties of Sn-0.7Cu–0.075Al are guaranteed by the refined microst structure, the dispersed IMC and the uniform stress distribution.
TL;DR: In this article, the authors characterized the boundedness and compactness of a Stevic-Sharma operator from Hardy spaces to Bloch spaces, and showed that it can be computed in polynomial time.
Abstract: Let \(H(\mathbb{D})\) denote the space of all analytic functions on the unit disc \(\mathbb{D}\) of the complex plane ℂ, \(\psi_{1},\psi_{2}\in H(\mathbb{D}) \), and φ be an analytic self-map of \(\mathbb{D}\). In this paper, we characterize the boundedness and compactness of a Stevic-Sharma operator \(T _{\psi_{1},\psi_{2},\varphi}\) from Hardy spaces \(H^{p}\) (with \(1\leq p<\infty\)) to the logarithmic Bloch spaces \(\mathcal{B}_{\mathrm{log}}\).
TL;DR: This paper designs an filter such that the filtering error system is mean-square asymptotically stable and satisfies a prescribed performance level and a simulation example is given to illustrate the effectiveness of the proposed filtering scheme.
Abstract: This paper investigates the filtering problem for stochastic systems driven by Poisson processes. By utilising the martingale theory such as the predictable projection operator and the dual predictable projection operator, this paper transforms the expectation of stochastic integral with respect to the Poisson process into the expectation of Lebesgue integral. Then, based on this, this paper designs an filter such that the filtering error system is mean-square asymptotically stable and satisfies a prescribed performance level. Finally, a simulation example is given to illustrate the effectiveness of the proposed filtering scheme.
TL;DR: In this article, the effect of BaTiO3 on the microstructure and mechanical properties of the SAC lead-free solder is investigated, and the results show that the β-Sn is refined and the volume fraction of the eutectic phase is increased.
Abstract: Minor weight fraction of the BaTiO3 particle is doped into the Sn1.0Ag0.5Cu (SAC) lead-free solder by the mechanically mixing. The effect of BaTiO3 on the microstructure and mechanical properties of the SAC lead-free solder is investigated. The results show that the β-Sn is refined and the volume fraction of the eutectic phase is increased by adding BaTiO3. The β-Sn morphology is transformed from the block into the lamellar in the SAC + 0.2 wt% BaTiO3, and a Cu6Sn5 IMC layer with thickness of about 7.3 μm is obtained. The optimal spreadability of the SAC–0.2BaTiO3 is obtained, and the spreading coefficient reaches 0.7836, it is 23.48 % higher than that of the SAC solder. The ultimate tensile strength and the elongation are improved by the BaTiO3 addition. The fracture surface of the SAC–0.2BaTiO3 solder specimen consists of large amounts of dimples due to the highly ductile manner.
TL;DR: In this paper, the first asymmetric inverse-electron demand oxa-Diels-Alder reaction of ortho-quinone methides, generated in situ from Ortho-hydroxybenzyl alcohols, was described using 3-methyl-2-vinylindoles as dienophiles.
Abstract: The first examples of an asymmetric inverse-electron demand oxa-Diels—Alder reaction of ortho-quinone methides, generated in situ from ortho-hydroxybenzyl alcohols, is described using 3-methyl-2-vinylindoles as dienophiles.
TL;DR: In this article, the ultraviolet photoresponse properties of a n-ZnO nanorods/p-diamond heterojunction were investigated by studying the dark and photo I-V characteristics.
Abstract: The ultraviolet (UV) photoresponse properties of a n-ZnO nanorods/p-diamond heterojunction were investigated by studying the dark and photo I–V characteristics. It shows typical rectifying behavior with a rectification ratio of 3.2 and 8.8 at 5 V for the dark current and the photocurrent, respectively. The turn on voltage under UV illumination is three times lower than that under the dark current and the ideality factor of the device is decreased. The forward current under UV illumination is more than 4 times higher than the dark one at 10 V whereas the leakage current shows a little increase at −10 V. The electrical transport behaviors are investigated both under the dark current and the photocurrent. The photogenerated charges and their transfer processes were analyzed by surface photovoltage (SPV) measurements.
TL;DR: In this paper, a comprehensive study of influence of twist extrusion (TE) process on consolidating pure aluminum powder in tubes (PITs) by equal channel angular pressing and torsion (ECAPT) was conducted via three-dimensional finite element simulation, experimental investigation and theoretical analysis.
TL;DR: In this article, the boundedness and compactness of the Stevic type operator was characterized from an analytic self-map of the complex plane to the logarithmic Bloch spaces.
Abstract: Let $$H({\mathbb {D}})$$
denote the space of all analytic functions on the unit disc $${\mathbb {D}}$$
of the complex plane $$ {\mathbb {C}}$$
, $$\psi _1,\psi _2\in H({\mathbb {D}})$$
, and $$\varphi $$
be an analytic self-map of $$ {\mathbb {D}}$$
. In this paper, we characterize the boundedness and compactness of Stevic type operator $$T _{\psi _1,\psi _2,\varphi }$$
from $$H^\infty $$
space to the logarithmic Bloch spaces $${\mathcal {B}}_{\log }$$
(
$${\mathcal {B}}_{\log ,0}$$
).
TL;DR: In this article, Zhou et al. investigated the steady state of a general Markovian two-stage continuous flow system by solving a system of differential equations that describes the dynamics of the system.
Abstract: Series-parallel systems with intermediate buffers widely exist in reality. For example, a production line can have multiple production phases connected in series. Each phase can have several production units organised in parallel to enhance the performance of the system. Between these phases, some intermediate buffers are allocated to store work in process (WIP). These buffers can reduce the influence of the breakdown and maintenance of a subsystem on the production rate of the whole system. However, the effects of intermediate buffers also make the degradation process of the system more difficult to model. Some existing papers developed methods to evaluate the performance of the series-parallel or series system with intermediate buffers. Tan and Gershwin [20] investigated the steady-state of a general Markovian two-stage continuous-flow system by solving a system of differential equations that describes the dynamics of the system. After that, Tan and Gershwin [19] further applied their model to the steadystate analysis of more general situations, e.g. systems with multiple components in series or parallel in each subsystem. Alexandros and Chrissoleon[1] analysed the steady-state of a two-workstation onebuffer follow line by using the Markovian property of the system. Liu et al. [13] investigated a system similar to that in Ref. [1], which considers the asynchronous operations of independent parallel units. The system was modelled by a Quasi-Birth-Death (QBD) process that can be solved efficiently. When there are more than two subsystems (components) in a series-parallel (series) system, the above-mentioned performance evaluation approaches based on steady-state analysis become impractical. Besides methods using the Monte Carlo simulation [9], some approximate approaches e.g., the aggregation method [4, 8, 21] and the decomposition method [5, 12], are developed to evaluate the performance of the system analytically. Although the above papers addressed the performance evaluation of a series-parallel system, these papers assumed a predetermined maintenance strategy, while the maintenance strategy optimisation is not considered. Yifan Zhou Zhisheng ZhAng
TL;DR: In this paper, the structural, electronic, and optical properties of lithium niobate under pressure using the plane-wave pseudopotential density functional theory by CASTEP code were theoretically studied.
Abstract: We theoretically study the structural, electronic, and optical properties of lithium niobate under pressure using the plane-wave pseudopotential density functional theory by CASTEP code. It was found that there is a phase transition from the R3c structure to the Pnma structure at a pressure of 18.7 GPa. The Pnma structure was dynamically stable according to the calculation of phonon dispersion. From the charge density distributions, there exist covalent interactions along the Nb–O bond. The hybridization between O 2p and Nb 4d orbital in the Pnma phase increases with increasing pressure, while it is not changed in the R3c phase. With increasing pressure, the average Nb–O bond length decreases and the Nb–O bond population increases, indicating the increased covalent character between Nb and O atoms under high pressure at Pnma phase, which leads to the increased hybridization between O 2p and Nb 4d orbitals. Furthermore, the optical dielectric function, refractive index, extinction coefficient, electron energy, loss and reflectivity are calculated.
TL;DR: In this paper, Ni-based WC coatings were successfully fabricated on Ti6Al4V titanium alloy substrate by the air plasma spraying (APS) process, and they were remelted with a continuous wave CO2 laser.
Abstract: Ni-based WC coatings were successfully fabricated on Ti6Al4V titanium alloy substrate by the air plasma spraying (APS) process. The as-sprayed coatings were remelted with a continuous wave CO2 laser. The coatings were characterized using a scanning electron microscope (SEM), an energy dispersive spectrometer (EDS), an X-ray diffractometer (XRD), a Vickers microhardness tester, a ball-on-disc friction and wear tester, and a 3D measuring laser microscope. The results indicated that the laser-remelted coatings possessed a more homogeneous microstructure and lower porosity, were more dense, and bonded well with the substrate. The lamellar structure and microcracks of the as-sprayed coatings were eliminated after laser remelting. The average porosity markedly decreased to 1.3% from 9.7% of the as-sprayed coating. Many needle dendrites grew outward from the dissolution surface of the WC, while massive precipitates abundantly appeared around and away from the WC particles. The microhardness of the laser-remelted coating was enhanced to 884.7–1363.3 HV0.3, which was much higher than that of the as-sprayed coatings and nearly three times higher than that of the substrate. Under the same load, the wear volume of the substrate was nearly 13 times higher than that of the laser-remelted coating and five times higher than that of the as-sprayed coating. The wear mechanism of the laser-remelted coating and the as-sprayed coating was mainly abrasive wear; however, the wear mechanisms of the substrate were a combination of adhesive wear, micro-cutting, and delamination wear.
TL;DR: In this article, the removal rates of total nitrogen and ammonium nitrogen averaged 52.61 and 45.71% at a hydraulic retention time of 1 h, and the nitrite and nitrate nitrogen concentrations remained at low levels in influent and effluent throughout the experiment.
Abstract: Ceramic honeycombs were used as bio-carriers for removal of nitrogen from municipal wastewater by a bioreactor under aerobic conditions. Firstly, we investigated the removal rates of total nitrogen and ammonium, nitrite and nitrate forms of nitrogen. The experimental results demonstrated that the removal rates of total and ammonium nitrogen averaged 52.61 and 45.71% at a hydraulic retention time of 1 h, and the nitrite and nitrate nitrogen concentrations remained at low levels in influent and effluent throughout the experiment. Then, we investigated whether the nitrification and denitrification processes could occur simultaneously in a reactor using isolation and biological diversity analyses. Finally, the simultaneous nitrification and denitrification mechanisms in the bioreactor containing the ceramic honeycomb were analyzed. The conclusion was that the special structural feature of the ceramic honeycomb served as a bio-carrier, resulting in aerobic and anoxic zones co-existing in the system.
TL;DR: In this article, the photocatalytic activity of nanocrystalline N-modified CeO 2 was evaluated in the reduction of aqueous Cr 6+ under visible-light (λ > 420 ) irradiation.
01 Aug 2015
TL;DR: A refined hybrid particle swarm optimization by combining with bacterial foraging optimization is proposed for odor source localization of a swarm of robots that can find an odor source with higher success rate.
Abstract: Odor source localization is a challenging task for mobile robots in the real world. A refined hybrid particle swarm optimization by combining with bacterial foraging optimization is proposed for odor source localization of a swarm of robots. In the proposed algorithm, a chemotaxis operation is integrated into particle swarm optimization to lead robots to track a plume, and an elimination-dispersal operation is adopted to prevent particles trapping in local minim. Simulation results show that the proposed method can find an odor source with higher success rate.
TL;DR: Cai et al. as discussed by the authors applied a selenium and actived carbon (AC) catalyst for the selective reduction of nitroarenes to their corresponding amines respectively using sodium borohydride (NaBH4) as a reducing source un-der mild conditions.
Abstract: A selenium and actived carbon (AC) catalyst has been applied for the selective reduction of nitroarenes to their corresponding amines respectively using sodium borohydride (NaBH4) as a reducing source un-der mild conditions. Under the optimized conditions, efficient and selective reduction of nitroarenes into the corresponding aromatic amines occurred over a recyclable selenium catalyst. The catalyst can be easily recovered after catalytic reaction and readily reused for 4 cycles with consistent activity hence reduces the cost of the catalyst. © 2015 BCREC UNDIP. All rights reserved. Received: 3rd May 2015; Revised: 5th October 2015; Accepted: 5th October 2015 How to Cite : Cai, K.Y., Zhou, Y.M. (2015). Reduction of Nitroarenes to Aromatic Amines with Sodium Borohydride in the Presence of Selenium and Actived Carbon. Bulletin of Chemical Reaction Engineering & Catalysis , 10 (3): 275-280. (doi:10.9767/bcrec.10.3.8512.275-280) Permalink/DOI : http://dx.doi.org/10.9767/bcrec.10.3.8512.275-280