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81.
Recent theoretical advances have identified several computational algorithms that can be implemented utilizing quantum information
processing (QIP), which gives an exponential speedup over the corresponding (known) algorithms on conventional computers.
QIP makes use of the counter-intuitive properties of quantum mechanics, such as entanglement and the superposition principle.
Unfortunately it has so far been impossible to build a practical QIP system that outperforms conventional computers. Atomic
ions confined in an array of interconnected traps represent a potentially scalable approach to QIP. All basic requirements
have been experimentally demonstrated in one and two qubit experiments. The remaining task is to scale the system to many
qubits while minimizing and correcting errors in the system. While this requires extremely challenging technological improvements,
no fundamental roadblocks are currently foreseen. 相似文献
82.
Response of an elastic Bingham fluid to oscillatory shear 总被引:1,自引:0,他引:1
The response of an elastic Bingham fluid to oscillatory strain has been modeled and compared with experiments on an oil-in-water emulsion. The newly developed model includes elastic solid deformation below the yield stress (or strain), and Newtonian flow above the yield stress. In sinusoidal oscillatory deformations at low strain amplitudes the stress response is sinusoidal and in phase with the strain. At large strain amplitudes, above the yield stress, the stress response is non-linear and is out of phase with strain because of the storage and release of elastic recoverable strain. In oscillatory deformation between parallel disks the non-uniform strain in the radial direction causes the location of the yield surface to move in-and-out during each oscillation. The radial location of the yield surface is calculated and the resulting torque on the stationary disk is determined. Torque waveforms are calculated for various strains and frequencies and compared to experiments on a model oil-in-water emulsion. Model parameters are evaluated independently: the elastic modulus of the emulsion is determined from data at low strains, the yield strain is determined from the phase shift between torque and strain, and the Bingham viscosity is determined from the frequency dependence of the torque at high strains. Using these parameters the torque waveforms are predicted quantitatively for all strains and frequencies. In accord with the model predictions the phase shift is found to depend on strain but to be independent of frequency.Notation
A
plate strain amplitude (parallel plates)
-
A
R
plate strain amplitude at disk edge (parallel disks)
-
G
elastic modulus
-
m
torque (parallel disks)
-
M
normalized torque (parallel disks) = 2m/R
30
-
N
ratio of viscous to elastic stresses (parallel plates) =µ A/
0 ratio of viscous to elastic stresses (parallel disks) =µ A
R/0
-
r
normalized radial position (parallel disks) =r/R
-
r
radial position (parallel disks)
-
R
disk radius (parallel disks)
-
t
normalized time = t — /2
-
t
time
-
E
elastic strain
-
P
plate strain (displacement of top plate or disk divided by distance between plates or disks)
-
PR
plate strain at disk edge (parallel disks)
-
0
yield strain
-
E
normalized elastic strain =
E/0
-
P
normalized plate strain =
P/0
-
PR
normalized plate strain at disk edge (parallel disks) =
PR/0
-
0
normalized plate strain amplitude (parallel plates) =A/
0 — normalized plate strain amplitude at disk edge (parallel disks) =A
R/0
-
phase shift between
P
andT (parallel plates) — phase shift between
PR
andM (parallel disks)
-
µ
Bingham viscosity
-
stress
-
0
yield stress
-
T
normalized stress =/
0
-
frequency 相似文献
83.
84.
85.
Iijima M Yoshimura M Tsuchiya T Tsukada M Ichikawa H Fukumori Y Kamiya H 《Langmuir : the ACS journal of surfaces and colloids》2008,24(8):3987-3992
A novel thermo- and pH-sensitive nanogel particle, which is a core-shell structured particle with a poly(N-isopropylacrylamide) (p(NIPAAm)) hydrogel core and a poly(ethylene glycol) monomethacrylate grafted poly(methacrylic acid) (p(MMA-g-EG)) shell, is of interest as a vehicle for the controlled release of peptide drugs. The interactions between such nanogel particles and artificial mucin layers during both approach and separation were successfully measured by using colloid probe atomic force microscopy (AFM) under various compression forces, scan velocities, and pH values. While the magnitudes of the compression forces and scan velocities did not affect the interactions during the approach process, the adhesive force during the separation process increased with these parameters. The pH values significantly influenced the interactions between the nanogel particles and a mucin layer. A large steric repulsive force and a long-range adhesive force were measured at neutral pH due to the swollen p(MMA-g-EG) shell. On the other hand, at low pH values, the steric repulsive force disappeared and a short-range adhesive force was detected, which resulted from the collapse of the shell layer. The nanogel particles possessed a pH response that was sufficient to protect the incorporated peptide drug under the harsh acidic conditions in the stomach and to effectively adhere to the mucin layer of the small intestine, where the pH is neutral. The relationships among the nanogel particle-mucin layer interactions, pH conditions, scan velocities, and compression forces were systemically investigated and discussed. 相似文献
86.
Yoshimura T Chen ZN Itasaka A Abe M Sasaki Y Ishizaka S Kitamura N Yarovoi SS Solodovnikov SF Fedorov VE 《Inorganic chemistry》2003,42(16):4857-4863
Hexarhenium(III) complexes with terminal isothiocyanate ligands, [(n-C(4)H(9))(4)N](4)[Re(6)(mu(3)-S)(8)(NCS)(6)] (1) and (L)(4)[Re(6)(mu(3)-Se)(8)(NCS)(6)] (L(+) = PPN(+) (2a), (n-C(4)H(9))(4)N(+) (2b)), have been prepared by three different methods. Complex 1 was prepared by the reaction of [(n-C(4)H(9))(4)N](4)[Re(6)(mu(3)-S)(8)Cl(6)] with molten KSCN at 200 degrees C, while 2b was obtained by refluxing the chlorobenzene-DMF (2:1 v/v) solution of [Re(6)(mu(3)-Se)(8)(CH(3)CN)(6)](SbF(6))(2) and [(n-C(4)H(9))(4)N]SCN. The [Re(6)(mu(3)-Se)(8)(NCS)(6)](4)(-) anion was also obtained from a mixture of Cs(2)[Re(6)(mu(3)-Se)(8)Br(4)] and KSCN in C(2)H(5)OH by a mechanochemical activation at room temperature for 20 h and isolated as 2a. The X-ray structures of 1 and 2a.4DMF have been determined (1, C(70)H(144)N(10)S(14)Re(6), monoclinic, space group P2(1)/n (No. 14), a = 14.464(7) A, b = 22.059(6) A, c = 16.642(8) A, beta = 113.62(3) degrees, V = 4864(3) A(3), Z = 2; 2a.4DMF, C(162)H(144)N(14)O(4)P(8)S(6)Se(8)Re(6), triclinic, space group P1 (No. 2), a = 15.263(2) A, b = 16.429(2) A, c = 17.111(3) A, alpha = 84.07(1) degrees, beta = 84.95(1) degrees, gamma = 74.21(1) degrees, V = 4098.3(8) A(3), Z = 1). All the NCS(-) ligands in both complexes are coordinated to the metal center via nitrogen site with the Re-N distances in the range of 2.07-2.13 A. The redox potentials of the reversible Re(III)(6)/Re(III)(5)Re(IV) process in acetonitrile are +0.84 and +0.70 V vs. Ag/AgCl for [Re(6)(mu(3)-S)(8)(NCS)(6)](4)(-) and [Re(6)(mu(3)-Se)(8)(NCS)(6)](4)(-), respectively, which are the most positive among the known hexarhenium complexes with six terminal anionic ligands. The complexes show strong red luminescence with the emission maxima (lambda(max)/nm), lifetimes (tau(em)/micros), and quantum yields (phi(em)) being 745 and 715, 10.4 and 11.8, and 0.091 and 0.15 for 1 and 2b, respectively, in acetonitrile. The data reasonably well fit in the energy-gap plots of other hexarhenium(III) complexes. The temperature dependence of the emission spectra and tau(em) of 1 and [(n-C(4)H(9))(4)N](4)[Re(6)(mu(3)-S)(8)Cl(6)] are also reported. 相似文献
87.
The formation of tetragonal Zr(0.5)Ce(0.5)O(2) solid solution nanocrystallites of 5 +/- 1 nm size by a hydrothermal method at 120 degrees C for 6 h was confirmed by careful Raman and XRD studies for the first time. It was characterized as the t' '-form with an axial ratio of c/a = 1 but with oxygen ion displacements. The as-prepared sample was hydrous in nature, which is responsible for the lattice expansion. However, most of the water held in the structure can be expelled by heating the sample above 600 degrees C. Above 1050 +/- 50 degrees C the t' '-form of tetragonal Zr(0.5)Ce(0.5)O(2) solid solution dissociates into two phases, cubic phase and the t-form of tetragonal phases. 相似文献
88.
A simple method for the rapid and simultaneous analysis of dichlorvos (DDVP), malathion, carbaryl, and 2,4-dichlorophenoxy acetic acid (2,4-D) in citrus fruit, which uses flow-injection ion spray ionization tandem mass spectrometry, has been developed for the first time. The method involves the combined use of stable isotopically labeled internal standards (DDVP-d6, malathion-d10, carbaryl-d7, and 2,4-D-d5) and a multiple reaction monitoring technique. The average recoveries for the pesticides at the same concentrations as their tolerance levels (DDVP: 0.1-0.2 μg g−1; malathion: 0.5-4.0 μg g−1; carbaryl: 1.0 μg g−1; 2,4-D: 1.0-2.0 μg g−1) ranged from 90 to 119% with the relative standard deviation (R.S.D.) ranging from 1.0 to 13.1% (n = 5). Analysis time, including sample preparation and determination, was only 15 min. The present method is effective for screening DDVP, malathion, carbaryl, and 2,4-D in citrus fruit. 相似文献
89.
Sakai K Umezawa S Tamura M Takamatsu Y Tsuchiya K Torigoe K Ohkubo T Yoshimura T Esumi K Sakai H Abe M 《Journal of colloid and interface science》2008,318(2):440-448
The adsorption and micellization behavior of novel sugar-based gemini surfactants (N,N(')-dialkyl-N,N(')-digluconamide ethylenediamine, Glu(n)-2-Glu(n), where n is the hydrocarbon chain length of 8, 10 and 12) has been studied on the basis of static/dynamic surface tension, fluorescence, dynamic light scattering (DLS) and cryogenic transmission electron microscope (cryo-TEM) data. The static surface tension of the aqueous Glu(n)-2-Glu(n) solutions measured at the critical micelle concentration (cmc) is observed to be significantly lower than that of the corresponding monomeric surfactants. This suggests that the gemini surfactants, newly synthesized in the current study, are able to form a closely packed monolayer film at the air/aqueous solution interface. The greater ability in the molecular association is supported by the remarkably (approximately 100-200 times) lower cmc of the gemini surfactants compared with the corresponding monomeric ones. With a combination of the fluorescence and DLS data, a structural transformation of the Glu(n)-2-Glu(n) micelles is suggested to occur with an increase in the concentration. The cryo-TEM measurements clearly confirm the formation of worm-like micelles of Glu(12)-2-Glu(12) at the concentration well above the cmc. 相似文献
90.