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51.
Using a variational approach, we have calculated the donor impurity related photoionization cross-section and impurity binding in GaAs/GaAlAs quantum-well wires under different temperature and hydrostatic pressure conditions. Our calculation have revealed the dependence of the photoionization cross-section and the impurity binding on temperature and hydrostatic pressure. 相似文献
52.
The rotational spectrum of a new monobridged isomer of Si(2)H(4), denoted here as H(2)Si(H)SiH, has been detected by Fourier transform microwave spectroscopy of a supersonic molecular beam through the discharge products of silane. On the basis of high-level coupled cluster theory, this isomer is calculated to lie only 7 kcalmol above disilene (H(2)SiSiH(2)), the most stable isomeric arrangement of Si(2)H(4), and to be fairly polar, with a calculated dipole moment of mu = 1.14 D. The rotational spectrum of H(2)Si(H)SiH exhibits closely spaced line doubling, characteristic of a molecule undergoing high-frequency inversion. Transition state calculations indicate that inversion probably occurs in two steps: migration of the bridged hydrogen atom to form silylsilylene, H(3)SiSiH, and then internal rotation of the SiH(3) group, followed by the reverse process. The potential energy surface for this type of inversion is quite shallow, with a barrier height of only 2-3 kcalmol. Searches for the rotational lines of silylsilylene, calculated to be of comparable stability to H(2)Si(H)SiH but about five times less polar (mu = 0.23 D), have also been undertaken, so far without success, even though strong lines of H(2)Si(H)SiH have been detected. The favorable energetics and high polarity of monobridged Si(2)H(4) with respect to either disilene or silylsilylene make it a plausible candidate for radioastronomical detection in sources such as IRC + 10216, where comparably large silicon molecules such as SiS, SiC(3), and SiC(4) have already been discovered. 相似文献
53.
From the aerial parts of Papaver triniifolium Boiss. (Papaveraceae) collected from Erzincan (Eastern Anatolia), two new benzylisoquinoline alkaloids, miltanthoridine and miltanthoridinone were isolated. Their structures were established through the use of UV, EIMS, and NMR techniques. 相似文献
54.
We have studied the magnetic field effects on the diamagnetic susceptibility and binding energy of a hydrogenic impurity in a quantum well-wire by taking into account spatially dependent screening. Using the effective-mass approximation within a variational scheme, binding energy and diamagnetic susceptibility of donor are obtained as a function of the magnetic field, length of the square quantum well-wire for different impurity positions. It is shown that the magnetic field effects on diamagnetic susceptibility can be more important for donors in quantum well-wires over a large range of wire dimensions. 相似文献
55.
Sari Lasanen Lassi Roininen Janne M.J. Huttunen 《Stochastic Processes and their Applications》2018,128(11):3607-3627
Linear second order elliptic boundary value problems (BVP) on bounded Lipschitz domains are studied in the case of Gaussian white noise loads. The challenging cases of Neumann and Robin BVPs are considered.The main obstacle for usual variational methods is the irregularity of the load. In particular, the Neumann boundary values are not well-defined.In this work, the BVP is formulated by replacing the continuity of boundary trace mappings with measurability. Instead of variational methods alone, the novel BVP derives also from Cameron–Martin space techniques.The new BVP returns the study of irregular white noise to the study of -loads. 相似文献
56.
E. Kasapoglu C. A. Duque H. Sari I. Sökmen 《The European Physical Journal B - Condensed Matter and Complex Systems》2011,82(1):13-17
By using the compact-density matrix approach, the effect of a nonresonant
intense laser field on the linear and nonlinear optical absorptions based on
intersubband transitions and the refractive index changes in an asymmetric
semiconductor quantum well have been presented. Our results show that the
peak position of the absorption coefficient is sensitive to intense laser
field, the absorption maximum shifts towards lower energies for increasing
intense laser field value. Also we observe as the intense laser field
strength increases, the total refractive index change has been increased in
magnitude and also shifted towards lower energies. The results indicate that
linear and nonlinear optical properties of the low dimensional semiconductor
heterostructures can be adjusted in a desired energy range by using intense
laser field. 相似文献
57.
C. A. Duque M. E. Mora-Ramos E. Kasapoglu H. Sari I. Sökmen 《The European Physical Journal B - Condensed Matter and Complex Systems》2011,81(4):441-449
In this work are studied the intense laser effects on the impurity states in GaAs-Ga1−
x
Al
x
As quantum wells under applied electric and magnetic fields. The electric field is taken oriented along the growth direction
of the quantum well whereas the magnetic field is considered to be in-plane. The calculations are made within the effective
mass and parabolic band approximations. The intense laser effects have been included through the Floquet method by modifying
the confinement potential associated to the heterostructure. The results are presented for several configurations of the dimensions
of the quantum well, the position of the impurity atom, the applied electric and magnetic fields, and the incident intense
laser radiation. The results suggest that for fixed geometry setups in the system, the binding energy is a decreasing function
of the electric field intensity while a dual monotonic behavior is detected when it varies with the magnitude of an applied
magnetic field, according to the intensity of the laser field radiation. 相似文献
58.
This study investigated the properties of immobilized β-galactosidase on polymeric beads having Schiff base. Polystyrene microspheres attached L-Alanine (FMPS-Ala) was synthesized from (4-formyl-3-methoxyphenoxymethyl)polystyrene (FMPS) and L-alanine by condensation. A coordinasyon polymer involving Ni2+(FMPS-Ala-Ni) was produced with the template method and characterized. β-galactosidase was immobilized onto the (FMPS), (FMPS-Ala) and (FMPS-Ala-Ni) complexes via covalent bonds. The Km/Vmax values were calculated as 0.343 mM/0.0259 mM min?1for free β-galactosidase and 0.104 mM/0.0126 mM min?1, 0.0617 mM/0.0417 mM min?1and 0.210 mM/0.0287 mM min?1for β-galactosidase immobilized to the (FMPS), (FMPS-Ala) and (FMPS-Ala-Ni) supports, respectively. The storage stability of (FMPS-Ala-Ni) was determined to be higher than that of the (FMPS) and (FMPS-Ala) polymers. 相似文献
59.
Sari Mkinen Jaakko Hiidenhovi Xin Huang Amanda dos Santos Lima Luciana Azevedo Jari Setl Anna-Liisa Vlimaa Pirjo Mattila Daniel Granato 《Molecules (Basel, Switzerland)》2022,27(18)
This study aimed to produce bioactive protein hydrolysates from undervalued fish, namely Baltic herring, and its filleting by-products. Protein hydrolysates were produced with Alcalase and Flavourzyme to achieve effective hydrolysis. The hydrolysates were evaluated for chemical composition, molecular weight distribution, antioxidant capacity, dipeptidyl-peptidase 4 (DPP4) inhibitory activity, effects on cell proliferation and surface hydrophobicity. The protein content of the hydrolysates was high, from 86% to 91% (dm), while the fat content was low, from 0.3% to 0.4% (dm). The hydrolysates showed high DPP4 inhibition activities with IC50 values from 5.38 mg/mL to 7.92 mg/mL. The scavenging activity of the hydrolysates towards DPPH was low, but an intermediate Folin–Ciocalteu reducing capacity and Cu2+ chelating ability was observed. The solid phase extraction with Sep-Pak C18 cartridges increased the DPP4 inhibition activity and antioxidant capacity, indicating peptides’ crucial role in the bioactivities. The cytotoxicity of the hydrolysates was evaluated on the HCT8, IMR90, and A549 cell lines. The hydrolysates inhibited cell growth in the cancer and normal cells, although they did not reduce cell viability and were not lethal. Overall, our results indicate that protein hydrolysates from Baltic herring have potential as health-promoting foods and nutraceuticals, especially for enhancing healthy blood glucose regulation. 相似文献
60.
Naciye Bihter Taylan Bekir Sari Halil Ibrahim Unal 《Journal of Polymer Science.Polymer Physics》2010,48(12):1290-1298
This study covers the synthesis of conducting polyindole (PIN) homopolymer, poly(vinyl chloride)/polyindole (PVC/PIN) composites, and preparation of their freestanding films. PIN and composites were synthesized chemically by radicalic mechanism using FeCl3 as an initiator. Films of PVC and PVC/PIN composites were prepared by casting on glass Petri dishes. Mechanical properties of films were examined by stress–strain experiments. From FTIR spectra of polymers, it was revealed that polymerization reaction occurred by 2–3 mechanism. The conductivities of polymers at different temperatures were also measured by four‐probe technique and found in the range 10?4 to 10?5 S cm?1. Magnetic properties of the polymers were analyzed by Gouy scale measurements and were found that their conducting mechanisms are of polaron and bipolaron natures. Thermal properties of polymers were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) and found that they had shown adequate thermal stability. X‐ray diffraction (XRD) spectra showed the amorphous nature of the polymers. Scanning electron microscopy (SEM) was used for microstructural analysis. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 1290–1298, 2010 相似文献