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101.
Qingzhao Yao Yuming Zhou Yanqing Sun Xiaoyun Ye 《Journal of Inorganic and Organometallic Polymers and Materials》2008,18(4):477-484
TiO2 hybrid molecular imprinted polymer (MIP) for ethofumesate using methacrylic acid (MAA) as the functional monomer and silane
coupling agent 3-(trimethoxysilyl) propylmethacrylate (KH570) as organic–inorganic connective bridge was synthesized via photo-excitation
method. Hydrogen bond was proved to act between MAA and ethofumesate for pre- and post-polymerization binding properties as
testified by UV spectrometric method. KH570 modified TiO2 nanoparticles were prepared via sonochemical reaction, which can accelerate hydrolysis, increase collision chance for the
reactive system and improve the dispersion of the nanoparticles. Scanning electron microscope (SEM), transmission electron
microscope (TEM), binding and the adsorption kinetics experiments as well as thermogravimetric analysis (TGA) were employed
for characterization. The results indicated that the hybrid MIP revealed a larger surface area and more ordered imprinting
cavities with improved thermal stability compared to organic-only MIP. Furthermore, faster adsorption kinetics and enhancive
adsorption capacity were achieved, which made it promising in chemical sensor applications. 相似文献
102.
Muhammad Maqbool Hugh H. Richardson Martin E. Kordesch 《Journal of Materials Science》2007,42(14):5657-5660
Thin films of Praseodymium doped AlN are deposited on silicon (111) substrates at 77 K and 950 K by rf magnetron sputtering
method. About 500–1000 nm thick films are grown at 100–200 watts RF power and 5–8 mTorr nitrogen, using a metal target of
Al with Pr. X-rays diffraction results show that films deposited at 77 K are amorphous and those deposited at 950 K are crystalline.
Cathodoluminescence studies are performed at room temperature and luminescence peaks are observed in a wide range from ultraviolet
to infrared region. The most intense peak is obtained in green at 526 nm from amorphous films as a result from 3P1→3H5 transition. In crystalline films the intense peak was obtain in red at 648 nm as a result from 3P0→3F2 transition. Films are thermally activated at 1300 K for half an hour in a nitrogen atmosphere. Thermal activation enhances
the intensity of luminescence. Two peaks at 488 nm and 505 nm merged after thermal activation, giving rise to a single peak
at 495 nm. 相似文献
103.
Zushu Li Kenneth C. Mills Malcolm McLean Kusuhiro Mukai 《Metallurgical and Materials Transactions B》2005,36(2):247-254
The densities of three Ni-based superalloys have been measured in both liquid and mushy states by both a modified sessile
drop method (MSDM) and a modified pycnometric method (MPM) for alloys CMSX-4 and CM186LC, and for CMSX-10 alloy by MSDM only.
The surface tensions of liquid CMSX-4, CM186LC, and CMSX-10 superalloys were measured using the sessile drop method. All measurements
were carried out in a highly purified argon atmosphere with the oxygen partial pressure of less than 10−19 MPa in the gas outlet. The densities of all superalloys in both liquid and mushy states were found to decrease with increasing
temperature. The volume thermal expansion of each superalloy in the mushy state was found to be higher than that in the liquid
state. The densities determined by different methods have been critically assessed and recommended values in both liquid and
mushy states are given as a linear function of temperature for the three Ni-based superalloys. The surface tension of liquid
CMSX-4 superalloy was found to decrease with increasing temperature, while that of liquid CMSX-10 superalloy increases with
increasing temperature. The wetting behavior of liquid CM186LC on the alumina substrate was found (1) to differ significantly
from that of CMSX-4 and CMSX-10 and (2) to vary with time. A HfO2-rich layer was found in the contact area of CM186LC with the alumina substrate, which could lead to some uncertainty in the
value obtained for the surface tension determined for CM186LC. 相似文献
104.
Application-level performance is a key to the adoption and success of the CDMA 2000. To predict this performance in advance,
a detailed end-to-end simulation model of a CDMA network is built to include application traffic characteristics, network
architecture, network element details using the proposed simulation methodology. We assess the user-perceived application
performance when a RAN and a CN adopt different transport architectures such as ATM and IP. To evaluate the user-perceived
quality of voice service, we compare the end-to-end packet delay for different vocoder schemes such as G.711, G.726 (PCM),
G.726 (ADPCM), and vocoder bypass scheme. By the simulation results, the vocoder bypass scenario shows 30% performance improvement
over the others. We also compare the quality of voice service with and without DPS scheduling scheme. We know that DPS scheme
keep the voice delay bound even if the service traffic is high. For data packet performance, HTTP v.1.1 shows better performance
than that of HTTP v.1.0 due to the pipelining and TCP persistent connection. We may conclude that IP transport technology
is better solution for higher FER environment since the packet overhead of IP is smaller than that of ATM for web browsing
data traffic, while it shows opposite effect to the small size voice packet in RAN architecture. We show that the 3G-1X EV-DO
system gives much better packet delay performance than 3G-1X RTT. The main conclusion is that end-to-end application-level
performance is affected by various elements and layers of the network and thus it must be considered in all phases of the
development process.
Jae-Hyun Kim He received the B.S., M.S., and Ph.D. degrees, all in computer science and engineering, from Hanyang University, Ansan, Korea,
in 1991, 1993, and 1996 respectively. In 1996, he was with the Communication Research Laboratory, Tokyo, Japan, as a Visiting
Scholar. From April 1997 to October 1998, he was a post-doctoral fellow at the department of electrical engineering, University
of California, Los Angeles. From November 1998 to February 2003, he worked as a member of technical staff in Performance Modeling
and QoS management department, Bell laboratories, Lucent Technologies, Holmdel, NJ. He has been with the department of electrical
engineering, Ajou University, Suwon, Korea, as an assistant professor since 2003. His research interests include QoS issues
and cross layer optimization for high-speed wireless communication. Dr. Kim was the recipient of the LGIC Thesis Prize and
Samsung Human-Tech Thesis Prize in 1993 and 1997, respectively. He is a member of the Korean Institute of Communication Sciences
(KICS), Korea Institute of Telematics and Electronis (KITE), Korea Information Science Society (KISS), and IEEE.
Hyun-Jin Lee received the B.S. degree in electrical engineering from Ajou University, Suwon, Korea, in 2004, and is working toward the
M.S. degree and Ph. D. degree in electrical engineering at Ajou University. He has been awarded Samsung Human-Tech Thesis
Prize in 2004. His research interests QoS, especially network optimization and wireless packet scheduling. He is a member
of the KICS.
Sung-Min Oh received the B.S. and M. S. degrees in electrical engineering form Ajou University, Suwon, Korea, in 2004, and is working
toward the Ph. D. degree in electrical engineering at Ajou University. His research interests QoS performance analysis and
4G network. He is a member of the KICS.
Sung-Hyun Cho received his B.S., M.S., and Ph.D. in computer science and engineering from Hanyang University, Korea, in 1995, 1997, and
2001, respectively. From 2001 to 2005, he has been with Samsung Advanced Institute of Technology, where he has been engaged
in the design and standardization of MAC and upper layers of B3G, IEEE 802.16e, and WiBro systems. He is currently a MAC part
leader in the telecommunication R&D center of Samsung Electronics. His research interests include 4G air interface design,
radio resource management, cross layer design, and handoff in wireless systems. 相似文献
105.
Is there a direct relationship between oral astringency and human salivary protein binding? 总被引:1,自引:0,他引:1
For decades, it is believed that astringency is due to the polyphenol-induced complexation of proline-rich salivary proteins
in the oral cavity. In order to compare for the first time the human sensory threshold concentrations and the salivary protein
binding activity of a series of astringent stimuli, human saliva protein was incubated for 5 min at 37 °C in the presence
of astringent food-derived compounds and, after micro-centrifugation, the amount of the target molecules in the supernatant
was quantitatively determined by HPLC-UV/Vis. Significant protein binding was observed for (−)-epigallocatechin-3-gallate,
(−)-gallocatechin-3-gallate, (+)-gallocatechin, and (−)-catechin-3-gallate, all of which containing at least one galloyl moiety
in the molecule and exhibiting rather high sensory thresholds of more than 200 μmol/L. In comparison, (+)-catechin and procyanidin
B2, both lacking in any galloyl function, showed only comparatively low binding activity and, most interestingly, quercetin-3-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside and 3-carboxymethyl-indole-1-N-β-d-glucopyranoside did not show any protein binding at all, although the later N- and O-glycosides exhibited extraordinarily low sensory threshold concentrations of less than 0.001 and 0.0003 μmol/L, respectively.
The data give some first evidence that the quantity of the non-bound, “free” astringent stimulus in the saliva liquid might
be more closely related to the sensory perception of astringency than the amount complexed or precipitated by proteins. It
is therefore questionable as to whether oral perception of astringency is related to the complexation and/or precipitation
of salivary proteins. 相似文献
106.
Jatuporn Wittayakun Pongtanawat Khemthong Sanchai Prayoonpokarach 《Korean Journal of Chemical Engineering》2008,25(4):861-864
Rice husk silica (RHS) in amorphous phase with 98% purity was prepared from a waste rice husk from rice milling by leaching
with hydrochloric acid and calcination. The RHS was used effectively as a silica source for the synthesis of zeolite Y in
sodium form (NaY). The zeolite in pure phase was obtained from a two-step synthetic route in which the starting gels were
mixed, aged for 24 h at room temperature and crystallized for 24 h at 90 °C. The diameter of single crystal particles from
a scanning electron microscope was approximately 1.0 μm, whereas the average particle diameter from laser diffraction particle
size analyzer was approximately 10 μm because of the agglomeration of small crystals. Longer crystallization time in this
route resulted in a mixed phase containing NaY and zeolite P in sodium form (NaP). In addition, a one-step synthetic route
(no aging) was studied and the product was also a mixed phase zeolite. 相似文献
107.
A novel method for the fabrication of highly ordered nanopore arrays with very small diameter of 14 nm was demonstrated by
using low-temperature anodization. Two-step anodization was carried out at 25 V, sulfuric acid concentration of 0.3 M, and
electrolyte temperature of −15 °C. After anodization, a regular pore array with mean diameter of 14 nm and interpore distance
of 65 nm was formed. The pore diameter and regular arrangement were confirmed by scanning electron microscopy (SEM) and fast
Fourier transformation (FFT), respectively. The present results strongly suggest that the diameter of pores in a highly ordered
alumina template can be reduced by lowering the anodization temperature. 相似文献
108.
In this work, the kinetics and mechanism of free-radical polymerisation of glycidyl methacrylate (GMA) using potassium peroxydisulphate
(PDS) as water soluble initiator in the presence of synthesized 1, 4-Bis (tributyl methyl ammonium) benzene dichloride (TBMABDC)
as multi-site phase transfer catalyst (MPTC) was studied. The polymerisation reactions were carried out under inert and unstirred
conditions at constant temperature of 60 ± 1°C in cyclohexane/water biphase media. The role of concentrations of monomer,
initiator, catalyst and volume fraction of aqueous phase, solvent polarity and temperature on the rate of polymerisation (Rp)
was ascertained. The order with respect to monomer and initiator was found to be unity. The order with respect to catalyst
was found to be 0.51. The rate of polymerisation is independent of ionic strength and pH of the medium. However, an increase
in the polarity of solvent has slightly increased the Rp value. Based on the results obtained, a suitable kinetic scheme has
been proposed to account for the experimental observations and its significance discussed. 相似文献
109.
In this paper, we present a general method to calculate the inverse and direct dynamic models of parallel robots. The models
are expressed in a closed form by a single equation in which all the elements needed are expressed. The solution is given
in terms of the dynamic models of the legs, the dynamics of the platform and some Jacobian matrices. The proposed method is
applied in this paper on two parallel robots with different structures.
Categories (2), (3). 相似文献
110.
Finite sample properties of estimators of spatial autoregressive models with autoregressive disturbances 总被引:1,自引:0,他引:1
The article investigates the finite sample properties of estimators for spatial autoregressive models where the disturbance
terms may follow a spatial autoregressive process. In particular we investigate the finite sample behavior of the feasible
generalized spatial two-stage least squares (FGS2SLS) estimator introduced by Kelejian and Prucha (1998), the maximum likelihood
(ML) estimator, as well as that of several other estimators. We find that the FGS2SLS estimator is virtually as efficient
as the ML estimator. This is important because the ML estimator is computationally burdensome, and may even be forbidding
in large samples, while the FGS2SLS estimator remains computationally feasible in large samples.
Received: 20 January 2001 / Accepted: 31 August 2001 相似文献