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991.
Let M be an open manifold with a symplectic form Ω, and N a manifold with dimN<dimM. We prove that submersions with symplectic fibres satisfy the h-principle. Such submersions define Dirac manifold structures on the given manifold. As an application to this result we show that CPn?CPk−1 admits a submersion into R2(2k−n) with symplectic fibres for n/2<k?n. 相似文献
992.
Natural convection boundary layer laminar flow from a horizontal circular cylinder with uniform heat flux in presence of heat generation has been investigated. The governing boundary layer equations are transformed into a non-dimensional form and the resulting non-linear systems of partial differential equations, which are solved numerically by two distinct methods namely: (i) implicit finite difference method together with the Keller-box scheme and (ii) perturbation solution technique. The results of the surface shear stress in terms of local skin-friction and the rate of heat transfer in terms of local Nusselt number, velocity distribution, velocity vectors, temperature distribution as well as streamlines, isotherms and isolines of pressure are shown by graphically for a selection of parameter set consisting of heat generation parameter. 相似文献
993.
Euaggelos E. Zotos Wei Chen Md Sanam Suraj Rajiv Aggarwal Charanpreet Kaur 《Journal of Nonlinear Modeling and Analysis》2020,2(4):551-564
The scope of this work is to reveal, by means of numerical methods, the escape process in a Hamiltonian system with five exits which describes
the problem of rearrangement multichannel scattering. For determining the
influence of the energy on the nature of the orbits we classify starting conditions of orbits in planes of two dimensions. All the complex basins of escape,
associated with the five escape channels of the system, are illustrated by using
color-coded diagrams. The distribution of time of the escape is correlated with
the corresponding escape basins. The uncertainty (fractal) dimension along
with the (boundary) basin entropy are computed for quantifying the degree of
fractality of the dynamical system. 相似文献
994.
Md.?MaqbulEmail authorView authors OrcID profile 《Mediterranean Journal of Mathematics》2018,15(4):179
In this paper, we study the existence and uniqueness of Stepanov-almost periodic mild solution to the non-autonomous neutral functional differential equation in a Banach space \(\mathbb {X},\) where the family of linear operators A(t) satisfies the ‘Acquistapace–Terreni’ conditions, the evolution family generated by \(A(t),t\in \mathbb {R},\) is exponentially stable, \((\gamma -A(\cdot ))^{-1}\) and \(\alpha (\cdot )\) are almost periodic, and F and G are Stepanov-almost periodic continuous functions.
相似文献
$$\begin{aligned} \frac{{\hbox {d}}}{\hbox {d}t}[u(t)-F(t,u(t-\alpha (t)))]= & {} A(t)[u(t)-F(t,u(t-\alpha (t)))]\\&+\,G(t,u(t),u(t-\alpha (t))),\quad t\in \mathbb {R}, \end{aligned}$$
995.
Iman Hassaninia Rahim Ghayour Habib Abiri Mohammad H. Sheikhi 《Central European Journal of Physics》2009,7(4):813-820
The effect of noise on the performance of Schottky Barrier Carbon Nanotube Field Effect Transistors (SB-CNTFETs) has been
investigated under various bias conditions. In order to calculate the noise power spectral density, the Non-Equilibrium Green’s
Function formalism (NEGF) is used to obtain the transmission coefficient and the number of carriers inside the channel. Results
are presented in two sections: In the first section the Hooge’s empirical rule is used to investigate the flicker noise properties
of SB-CNTFETs with defects in the gate oxide region, while in the second section the thermal and shot noise properties of
SB-CNTFETs are studied. Finally, the best bias points in the ON and OFF states have been suggested according to the total
noise power spectral density and the device signal to noise ratio.
相似文献
996.
Rakesh K. Sindhu Rishu Verma Twinkle Salgotra Md. Habibur Rahman Muddaser Shah Rokeya Akter Waheed Murad Sidra Mubin Parveen Bibi Safaa Qusti Eida M. Alshammari Gaber El-Saber Batiha Micha Tomczyk Hayder M. Al-kuraishy 《Molecules (Basel, Switzerland)》2021,26(17)
Breast cancer persists as a diffuse source of cancer despite persistent detection and treatment. Flavonoids, a type of polyphenol, appear to be a productive option in the treatment of breast cancer, because of their capacity to regulate the tumor related functions of class of compounds. Plant polyphenols are flavonoids that appear to exhibit properties which are beneficial for breast cancer therapy. Numerous epidemiologic studies have been performed on the dynamic effect of plant polyphenols in the prevention of breast cancer. There are also subclasses of flavonoids that have antioxidant and anticarcinogenic activity. These can regulate the scavenging activity of reactive oxygen species (ROS) which help in cell cycle arrest and suppress the uncontrolled division of cancer cells. Numerous studies have also been performed at the population level, one of which reported a connection between cancer risk and intake of dietary flavonoids. Breast cancer appears to show intertumoral heterogeneity with estrogen receptor positive and negative cells. This review describes breast cancer, its various factors, and the function of flavonoids in the prevention and treatment of breast cancer, namely, how flavonoids and their subtypes are used in treatment. This review proposes that cancer risk can be reduced, and that cancer can be even cured by improving dietary intake. A large number of studies also suggested that the intake of fruit and vegetables is associated with reduced breast cancer and paper also includes the role and the use of nanodelivery of flavonoids in the healing of breast cancer. In addition, the therapeutic potential of orally administered phyto-bioactive compounds (PBCs) is narrowed because of poor stability and oral bioavailability of compounds in the gastrointestinal tract (GIT), and solubility also affects bioavailability. In recent years, creative nanotechnology-based approaches have been advised to enhance the activity of PBCs. Nanotechnology also offers the potential to become aware of disease at earlier stages, such as the detection of hidden or unconcealed metastasis colonies in patients diagnosed with lung, colon, prostate, ovarian, and breast cancer. However, nanoformulation-related effects and safety must not be overlooked. This review gives a brief discussion of nanoformulations and the effect of nanotechnology on herbal drugs. 相似文献
997.
H. D. A. Chathumal Jayaweera Md. Mamdudur Rahman Perry J. Pellechia Mark D. Smith Dmitry V. Peryshkov 《Chemical science》2021,12(31):10441
Carbon atom functionalization via generation of carbanions is the cornerstone of carborane chemistry. In this work, we report the synthesis and structural characterization of free ortho-carboranyl [C2B10H11]−, a three-dimensional inorganic analog of the elusive phenyl anion that features a “naked” carbanion center. The first example of a stable, discrete C(H)-deprotonated carborane anion was isolated as a completely separated ion pair with a crown ether-encapsulated potassium cation. An analogous approach led to the isolation and structural characterization of a doubly deprotonated 1,1′-bis(o-carborane) anion [C2B10H10]22−, which is the first example of a discrete molecular dicarbanion. These reactive carbanions are key intermediates in carbon vertex chemistry of carborane clusters.Free three-dimensional carborane carbanions, which are inorganic siblings of deprotonated aryls with the “naked” anionic carbon atom are reported. 相似文献
998.
A macrocyclic dinuclear copper complex, [Cu2II(1)Br4]·2H2O has been synthesized and characterized by X-ray crystallography, in which each metal ion is pentacoordinated in a square pyramidal environment and the macrocycle is folded to form a boat-shaped empty cavity. As studied by an indicator displacement assay, the dinuclear complex shows strong selectivity for phosphate over sulfate, nitrate, perchlorate and halides in water at physiological pH. 相似文献
999.
Moradian F Khajeh K Naderi-Manesh H Ahmadvand R Sajedi RH Sadeghizadeh M 《Applied biochemistry and biotechnology》2006,134(1):77-87
Two Bacillus sp. strains, HR-08 and KR-8102, isolated from soil of the west and north parts of Iran were screened on gelatin agar medium
for their ability to produce alkaline protease. The enzymes were active in a wide pH range (6.0–11.0) and stable in the alkaline
range (7.0–12.0). The optimum temperatures for the protease from HR-08 and KR-8102 were 65 and 50°C, respectively. The irreversible
thermoinactivation of HR-08 and KR-8102 proteases showed that the stability of HR-08 enzyme was higher than that of KR-8102
and the half-lives of these enzymes were 95 and 32 min at 50°C, respectively. In the presence of 10 mM Ca2+, HR-08 retained 100, 90, and 20% of its initial activity after heating for 30 min at 50, 60, and 70°C, respectively. Enzymes
were inhibited by phenylmethylsulfonyl fluoride and iodoacetate. After inhibition by iodoacetate, both enzymes were reactivated
by dithiothreitol. These data show that the enzymes seem to be thiol-dependent serine alkaline proteases. The enzymes especially
from HR-08 were stable in the presence of H2O2, surfactants, and local detergents; their activities were enhanced in the presence of 5 mM Fe2+; and the presence of 5mM metal ions such as Mg2+, Cu2+, and Mn2+ produced almost no effect. 相似文献
1000.
Md Rafiqul Islam K. SugitaM. Horie A. HashimotoA. Yamamoto 《Journal of Crystal Growth》2009,311(10):2817-2820
The Mg doping behavior of MOVPE indium gallium nitride (InGaN), such as secondary ion mass spectrometry (SIMS) Mg profile, crystalline quality and n–p conversion of the films are described and discussed in this paper. The SIMS analysis reveals that the memory effect of Cp2Mg as a doping source deteriorates the controllability of Mg doping level and profile, especially for thin (−0.4 μm) InGaN. The high residual donors (1019–1020 cm−3) in InGaN with In content from 0.05 to 0.37 can be compensated by Mg doping and p-type conduction is obtained for those with In content up to 0.2. It is found that a higher Cp2Mg flow rate is needed to get p-type conduction in InGaN with a higher In content x; for example, Cp2Mg/(TEG+TMI)≈0.5% for x=0 (GaN), ≈2% for x=0.05 and ≈4% for x=0.2. Such a high Cp2Mg flow rate is needed due to the high residual donor concentration (1019–1020 cm−3) of InGaN films and the low activation efficiency of Mg. The crystalline quality of InGaN is deteriorated with increasing In content as well as Mg doping level. To achieve a p-type InGaN with a lower Mg doping, it is essential to improve the crystalline quality of non-doped InGaN. For this purpose, the use of a thicker GaN interlayer is effective. 相似文献