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排序方式: 共有399条查询结果,搜索用时 218 毫秒
111.
T.C. Sharma L.W. Swenson K.S. Krane P. Varghese D.K. McDaniels H.A. Thiessen N. Tanaka R.R. Silbar M. Greenfield C.F. Moore 《Nuclear Physics A》1980,333(3):461-476
A singles measurement of the quasielastic scattering of 255 MeV pions by 27Al and 208Pb has been made. The measured values for the ratio R of π+ and π? induced cross section, averaged over all measured angles of 2.2 ± 0.2 and 1.5 ± 0.1 for 27Al and 208Pb respectively are substantially below the classical impulse approximation value of 11. A semiclassical nucleon charge exchange model is described for singles and coincidence measurements and is compared with the measured proton spectra. The comparison indicates that the singles proton spectra are dominated by events other than the quasielastic process whereas the coincidence data reported earlier and compared with the present calculations support the quasielastic interpretation. A strongly decreasing dependence of R on A for coincidence measurements may be interpreted as supporting the view that recoil nucleon charge exchange plays an important role in the quasielastic knockout process. 相似文献
112.
The influence of static magnetic field of strength 0.75 T on the nucleation of calcium carbonate crystals has been investigated. Particle size analysis shows that magnetic field can cause marked difference in distribution. One of the major impacts of magnetic exposure is the increase in number of the critical nuclei formed. Also, magnetic field promotes the formation of parallelepipedic calcite crystals and the dissolution of the smaller crystals by Ostwald ripening mechanism. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
113.
Single crystals of the title compound Ca (C4H5O5)2.10H2O are grown in silica gel using controlled chemical reaction method. Multifaceted single crystals of size up to 8 × 4 × 2 mm3 are obtained. Powder X‐ray Diffraction (XRD) pattern of the grown crystal and the Fourier Transform Infra‐Red (FTIR) spectrum in the range 400–4000 cm–1 are recorded. The vibrational bands corresponding to different functional groups are assigned. Thermal decomposition stages observed in the Thermo‐gravimetric (TG) and Differential Thermal Analysis (DTA) studies are discussed. A six‐stage thermal decomposition scheme is proposed for the compound. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
114.
Hema Tresa Varghese C. Yohannan Panicker Daizy Philip 《Journal of Raman spectroscopy : JRS》2007,38(3):309-315
IR, Raman and surface‐enhanced Raman scattering (SERS) spectra of 5‐sulphosalicylic acid were recorded and analysed. The vibrational wavenumbers were computed by density functional theoretical (DFT) method using B3LYP/6–31G* basis. The bands due to the stretching modes CO, C S and SO2 are intense in the SERS spectrum. The C H stretching mode also appears in the SERS spectrum. The molecule is found to adsorb through both the carboxyl and sulphonyl groups. A possible tilted orientation of the molecule is suggested. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
115.
S. Aruna G. Bhagavannarayana M. Palanisamy Preema C. Thomas Babu Varghese P. Sagayaraj 《Journal of Crystal Growth》2007,300(2):403-408
Optically good quality single crystal of l-argininium perchlorate (abbreviated as LARPCL), a promising analog of LAP was successfully grown by slow solvent evaporation technique at room temperature. The unit cell parameters and the morphology of LARPCL single crystals were determined by single crystal XRD. The Vickers microhardness measurements were carried out on the grown crystals to estimate the mechanical properties. The dielectric constant and dielectric loss of the crystal were measured as a function of frequency and temperature, and the results are discussed. 相似文献
116.
Maria Varghese Rae S. Rokosh Carolyn A. Haller Stacy L. Chin Jiaxuan Chen Erbin Dai Ruiqing Xiao Elliot L. Chaikof Mark W. Grinstaff 《Chemical science》2021,12(38):12719
Anticoagulant therapeutics are a mainstay of modern surgery and of clotting disorder management such as venous thrombosis, yet performance and supply limitations exist for the most widely used agent – heparin. Herein we report the first synthesis, characterization, and performance of sulfated poly-amido-saccharides (sulPASs) as heparin mimetics. sulPASs inhibit the intrinsic pathway of coagulation, specifically FXa and FXIa, as revealed by ex vivo human plasma clotting assays and serine protease inhibition assays. sulPASs activity positively correlates with molecular weight and degree of sulfation. Importantly, sulPASs are not degraded by heparanases and are non-hemolytic. In addition, their activity is reversed by protamine sulfate, unlike small molecule anticoagulants. In an in vivo murine model, sulPASs extend clotting time in a dose dependent manner with bleeding risk comparable to heparin. These findings support continued development of synthetic anticoagulants to address the clinical risks and shortages associated with heparin.Heparin mimicking sulfated poly-amido-saccharides (sulPASs) are anticoagulants resistant to heparanases and reversed by protamine sulfate. In an in vivo murine model, sulPASs extend clotting time without the increased risk of bleeding. 相似文献
117.
Varghese Mathew Lizymol Xavier C. K. Mahadevan K. E. Abraham 《Journal of Thermal Analysis and Calorimetry》2011,105(1):123-127
Thermal decomposition of manganese malonate dihydrate single crystals grown by gel method has been studied using the TG-DTA
and DSC techniques. The presence of water molecules and the dehydration stages are discussed. Dielectric constant, dielectric
loss, and AC conductivity have been estimated as a function of temperature in the range of 40–120 °C for four different frequencies.
Thermal studies reveal that the material is thermally stable up to123 °C. The dielectric measurements indicate that the dielectric
parameters increase with the increase in temperature. Also, the dielectric constant and dielectric loss factor values decrease
whereas the electrical conductivities increase with the increase in frequency of the AC applied. 相似文献
118.
Kaloor S. Harikrishnan Nithiyanandan Krishnan Nilima Manoj Kumar Anusree Krishna Gowtham Raj Devanathan Perumal Jemshiya Kalathil Jithu Krishna Dr. Reji Varghese 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(56):14100-14107
Two major hurdles in NP-based catalysis are the aggregation of the NPs and their recycling. Immobilization of NPs onto a 2D support is the most promising strategy to overcome these difficulties. Herein, amphiphilicity-driven self-assembly of galactose-hexaphenylbenzene-based amphiphiles into galactose-decorated 2D nanosheet is reported. The extremely dense decoration of reducing sugar on the surface of the sheets is used for the in situ synthesis and immobilization of ultrafine catalytically active AgNPs by using Tollens’ reaction. The potential of the system as a catalyst for the reduction of various nitroaromatics is demonstrated. Enhanced catalytic activity is observed for the immobilized AgNPs when compared to the corresponding discrete AgNPs. Recovery of the catalytic system from the reaction mixture by ultrafiltration and its subsequent recycling for several cycles without dropping its activity is shown. This is the first report demonstrating the in situ synthesis and immobilization of ultrafine AgNPs onto a 2D nanosheet that exhibits excellent catalytic performance for the reduction of nitroaromatics. 相似文献
119.
Shaji Varghese Chokkalinkam Anand Dattatray Dhawale Ajayan ManoVeerappan V. Balasubramanian George Allen Gnana RajSamuthira Nagarajan Mohammad A. WahabAjayan Vinu 《Tetrahedron letters》2012,53(42):5656-5659
A novel mesoporous catalyst, CuAl-SBA-15, with a hexagonally ordered porous structure prepared via a soft-templating approach in a highly acidic medium is used for tandem C-C and C-O bond formation between phenols and allylic alcohols to afford a variety of dihydrobenzopyrans in good yields. The catalyst is also found to be highly active for the synthesis of vitamin E and can be recycled several times without significant loss of its activity. 相似文献
120.
FakhrEldin O. Suliman Beena Varghese 《Journal of inclusion phenomena and macrocyclic chemistry》2018,91(3-4):179-188
The inclusion complexes of the proton pump inhibitor (PPI) pantoprazole sodium (PNZNa) with β-cyclodextrin (βCD) and cucurbit[7]uril (CB[7]) have been investigated. Fluorescence spectroscopy and electrospray ionization mass spectrometry (ESI-MS) were used to characterize these complexes. The fluorescence intensity of PNZNa was remarkably enhanced by both hosts, indicating the formation of the complexes. Nevertheless, the two hosts are of comparable cavity size their effect on the fluorescence of PNZNa was quite different. The ESI-MS data on the other hand confirmed the formation of a 1:1 PNZNa: host inclusion complexes for the two hosts. We further utilized molecular dynamics to shed more light on the mechanism of complexation and on the stability of these complexes in aqueous media. The complexes were stabilized over the 20 ns of simulation time mainly via hydrogen bonding interactions in addition to hydrophobic effects and van der Waals interactions. Snapshots collected during the simulations for both complexes have clearly shown that the mode of insertion of PNZ into the two host’s cavities are different which explain the difference in fluorescence enhancement of PNZ obtained in presence of each of these hosts. 相似文献