1,556 research outputs found
Carbon Dot as Visible-Light Photoredox Catalysts for a Myriad of Organic Transformations
No full textMetal-free catalysts for various organic transformations are of high demand now. In this study, we present a new carbon dot as an efficient metal-free nanophotocatalyst for carrying out a series of organic bond formation reactions. Using a single photocatalyst carbon dot, Csp2-Csp2, Csp2-B, Csp2-S, Csp2-Se, and C-P bond formation reactions were performed with a high yield of the corresponding products. Moreover, Csp2-H activation of the aromatic ring was achieved by merging the carbon dot photocatalyst with a transition metal. Interestingly, these carbon nanodot-based catalysts show good recyclability a few times without any significant loss of catalytic activity. The development of catalytic systems based on carbon dots has its merits vested in the advantageous properties of this nanomaterial, such as a robust chemical nature and cheap cost of preparation. This report demonstrates that a carbon dot indeed holds the potential to replace expensive metal-based catalysts as well as organic dyes in five different photoredox reactions
Synthesis and X-ray crystallographic characterization of copper and iron complexes with tetradentate-N-4 ligands: Reactivity towards catechol oxidation
No full textThe reaction of copper chloride dihydrate and ferric chloride hexahydrate with a tripodal N-4 ligand (ntb) under mild conditions affords two novel complexes [Cu(ntb)Cl](2)[CuCl4] (.) 2H(2)O (1) and [Fe(ntb)Cl-2]Cl (.) 3H(2)O (2). The reaction of ferric chloride with another N-4 ligand, bispicpn, forms an octahedral mononuclear complex, [Fe(bispicpn)Cl-2]Cl (3). Single-crystal X-ray structural Studies of 1, 2 and 3 reveal the formation of hydrogen-bond sustained 3D, 2D and 1D networks, respectively, involving (N-(HO)-O-...) and (N-(HCl)-Cl-...) interactions. The packing arrangement in 2 further reveals the existence of hexagonal channels with helical propagation along the diagonal of the crystallographic b- and c-axes. The reactions of these complexes with 3,5-di-tert-butyl-catechol have been studied in dimethylformamide. NMR techniques have been used to identify the reaction products
Rotational and vibrational cooling in pulsed high-pressure molecular beam expansions from 3 bar into the supercritical regime.
No full textExperiments employing pulsed high-pressure ( S(1)(0-0) transition by an asymmetric-top/free-internal-rotor simulation and compared with the results of a simpler rigid-rotor asymmetric-top tit. The experiments show that average rotational temperatures of ca. K in argon and 13-15 K in CO(2) can he reached at the highest pressures studied. The population of higher vertical bar m vertical bar torsional levels of p-fluorotoluene is clearly demonstrated by the appearance of characteristic features on the blue edge of the contours, which are more pronounced in the warmer CO(2) expansions. While the rotational temperatures in nitrogen expansions compare well with estimated CO(2) dynamical terminal translation temperatures, there are Considerable differences in the case of CO(2). Still, the degree of internal cooling reached with CO(2) is sufficiently low, so that a setup of this kind :bight provide good opportunities for future studies of thermally labile low-volatile molecules to cool them to cryogenic temperatures low enough to achieve a sufficient amplification of their spectra.University of Bristo
Steatoda cingulata
No full text<i>Steatoda cingulata</i> (Thorell, 1890) <p> <i>Stethopoma cingulatum</i> Thorell, 1890: 289 (♁ ♀).</p> <p> <i>Steatoda cingulata</i> Namkung, 1964: 34, fig. 10; Zhu, 1998: 329, fig. 220A–E (♁ ♀).</p> <p> <i>Steatoda panja</i> Barrion, Barrion-Dupo & Heong, in Barrion <i>et al.</i>, 2013: 39, fig. 45A–E. <b>syn. nov.</b></p> <p>For a complete list of taxonomic references see World Spider Catalog (2023).</p> <p> <b> Type material of <i>Steatoda panja</i> (examined).</b> Holotype ♁ (coll. No. SO 31), <b>CHINA:</b> Hainan Island, Panja, Songtao Reservoir, 3.IV.2011, leg. A. T. Barrion <i>et al.</i></p> <p> <b>Description and diagnosis.</b> See Zhu (1998) for a redescription and diagnosis of both sexes.</p> <p> <b>Distribution.</b> China (Anhui, Guangdong, Guangxi, Hainan, Hunan, Sichuan, Guizhou, Gansu, Taiwan, Zhejiang), India, Korea, Vietnam, Laos, Japan and Indonesia.</p> <p> <b>Comments.</b> The holotype male of <i>S. panja</i> was examined and found to be consistent with the morphology of <i>S. cingulata</i>. Thus, we consider <i>S. panja</i> <b>syn. nov.</b> to be a junior synonym of <i>S. cingulata.</i></p>Published as part of <i>Lin, Yejie, Wu, Lingbing, Cai, Ducheng, Li, Shuqiang, Barrion, Alberto Tomas & Heong, Kong-Luen, 2023, Review of 43 spider species from Hainan Island, China (Arachnida, Araneae), pp. 501-533 in Zootaxa 5351 (5)</i> on page 522, DOI: 10.11646/zootaxa.5351.5.1, <a href="http://zenodo.org/record/8392152">http://zenodo.org/record/8392152</a>
Impact of permeability heterogeneity on geothermal battery energy storage
Get PDFIn the emergence of new technologies to harness renewable energy, industrial-scale storage of heated water in a geothermal system is a promising technique. A porous, permeable medium, bounded by a poorly thermally conductive/convective overburden and underburden, can be used for transient subsurface thermal storage. The reservoir in this concept forms a geothermal battery. As a very simplified scenario, consider a single well injecting and producing hot water diurnally or seasonally. The source of the hot water could be solar-heated water, for example, or possibly even water heated from the excess regional electricity supply. For that situation, this study investigates the influence of spatial permeability heterogeneity on heat recovery, and the distributions of temperature and pressure inside the reservoir. Four heterogeneous models are created from lognormal distributions of permeability by varying the standard deviations while keeping the mean absolute permeability at 100 mD. The injection pressure experienced while pumping into a candidate formation is affected by heterogeneity; higher bottom hole pressure is required to inject water into a more heterogeneous reservoir. The spatial distribution of temperature is less affected by permeability heterogeneity. In the simulations carried out, 91% of the heat is recovered after the 30th cycle of injection/production operation in all cases proving less impact of heterogeneity on heat recovery for fixed injection and production rates.Cited as: Panja, P., McLennan, J., Green, S. Impact of permeability heterogeneity on geothermal battery energy storage. Advances in Geo-Energy Research, 2021, 5(2): 127-138, doi: 10.46690/ager.2021.02.0
Conformationally induced vibronic transitions in S<SUB>0</SUB>←S<SUB>1</SUB> spectra of n-propylbenzene
No full textDispersed fluorescence spectra(S0←S1) of two conformational isomers of n-propylbenzene have been measured in a supersonic free jet expansion. The results show that the vibronic features in emission from the S1 zero-point levels in two conformers are significantly different, and most notably, the transitions due to ring-chain torsional mode are active only in the spectra of the gauche conformer. Relative stability of the conformers in the ground state has been reinvestigated by the ab initio quantum chemistry method at the MP2/6-311++G(d,p) and MP2/ccpVTZ levels of theory. In contrast to earlier reports, the present theoretical studies predict that the gauche conformer is ∼2.5 kJ/mol more stable [MP2/6-311++G(d,p)] than the trans. The effects of propyl substitution on phenyl ring vibrational modes have been analyzed by comparing the calculated (ab initio, DFT/B3LYP/6-31G* *) displacements of ring atoms for different normal modes with those of the vibrational modes of unsubstituted benzene. The implications of spectral dissimilarity of the conformers on their excited state lifetimes [Borst et al., J. Chem. Phys. 116, 7057 (2002)] have been discussed
Probing color coherence effects in pp collisions at √s = 7 TeV
Get PDFOpen Access This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the
source are credited. Funded by SCOAP3 / License Version CC BY 4.0.A study of color coherence effects in pp collisions at a center-of-mass energy of 7TeV is presented. The data used in the analysis were collected in 2010 with the CMS detector at the LHC and correspond to an integrated luminosity of 36 pb-1. Events are selected that contain at least three jets and where the two jets with the largest transverse momentum exhibit a back-to-back topology. The measured angular correlation between the second- and third-leading jet is shown to be sensitive to color coherence effects, and is compared to the predictions of Monte Carlo models with various implementations of color coherence. None of the models describe the data satisfactorily.BMWF and FWF (Austria); FNRS and FWO(Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil);MES
(Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia); RPF(Cyprus); MoER, SF0690030s09 and ERDF (Estonia); Academy of Finland, MEC, and HIP (Finland);
CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NIH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF and WCU (Republic of
Korea); LAS (Lithuania); CINVESTAV, CONACYT, SEP, andUASLPFAI (Mexico); MBIE (New Zealand); PAEC (Pakistan); MSHE and NSC (Poland); FCT (Portugal); JINR (Dubna); MON, RosAtom, RAS and RFBR(Russia);MESTD (Serbia); SEIDI and CPAN(Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); ThEPCenter, IPST, STAR and NSTDA (Thailand); TUBITAK and TAEK (Turkey); NASU (Ukraine); STFC (United Kingdom); DOE and NSF (USA)
From interpolative contractive mappings to generalized Ciric-quasi contraction mappings
Get PDF[EN] In this article we consider a restricted version of Ciric-quasi contraction mapping for showing that this mapping generalizes several known interpolative type contractive mappings. Also here we introduce the concept of interpolative strictly contractive type mapping T and prove a fixed point theorem for such mapping over a T-orbitally compact metric space. Some examples are given in support of our established results. Finally we give an observation regarding (λ, α, β)-interpolative Kannan contractions introduced by Gaba et al.First and second authors acknowledge financial support awarded by the Council of Scientific and Industrial Research, New Delhi, India, through research fellowship for carrying out research work leading to the preparation of this manuscript.Roy, K.; Panja, S. (2021). From interpolative contractive mappings to generalized Ciric-quasi contraction mappings. Applied General Topology. 22(1):109-120. https://doi.org/10.4995/agt.2021.14045OJS109120221C. B. Ampadu, Some fixed point theory results for the interpolative Berinde weak operator, Earthline Journal of Mathematical Sciences 4 no. 2 (2020), 253-271. https://doi.org/10.34198/ejms.4220.253271S. Banach, Sur les opérations dans les ensembles abstraits et leur application aux équations intégrales, Fund. Math. 3 (1922), 133-181. https://doi.org/10.4064/fm-3-1-133-181L. B. Ciric, A generalization of Banach's contraction principle, Proc. Amer. Math. Soc. 45, no. 2 (1974), 267-273. https://doi.org/10.2307/2040075H. Garai, L. K. Dey and T. Senapati, On Kannan-type contractive mappings, Numerical Functional Analysis and Optimization 39, no. 13 (2018), 1466-1476. https://doi.org/10.1080/01630563.2018.1485157L. B. Ciric, Generalized contractions and fixed-point theorems, Publ. Inst. Math. 12 (1971), 19-26.Y. U. Gaba and E. Karapinar, A new approach to the interpolative contractions, Axioms 8, no. 4 (2019), 110. https://doi.org/10.3390/axioms8040110E. Karapinar, Revisiting the Kannan type contractions via interpolation. Adv. Theory Nonlinear Anal. Appl. 2, no. 2 (2018), 85-87. https://doi.org/10.31197/atnaa.431135E. Karapinar, R. P. Agarwal and H. Aydi, Interpolative Reich-Rus-Ciric type contractions on partial metric spaces, Mathematics 6, no. 11 (2018), 256. https://doi.org/10.3390/math6110256E. Karapinar, O. Alqahtani and H. Aydi, On interpolative Hardy-Rogers type contractions, Symmetry 11, no. 1 (2018), 8. https://doi.org/10.3390/sym11010008A. F. Roldán López de Hierro, E. Karapinar and A. Fulga, Multiparametric contractions and related Hardy-Roger type fixed point theorems, Mathematics 8, no. 6 (2020), 957. https://doi.org/10.3390/math806095
Measurement of the prompt J/ψ and ψ(2S) polarizations in pp collisions at s=7 TeV
Get PDFThis is the pre-print version of the final published paper that is available from the link below.The polarizations of prompt J/ψ and ψ(2S) mesons are measured in proton-proton collisions at s=7 TeV, using a dimuon data sample collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 4.9 fb. The prompt J/ψ and ψ(2S) polarization parameters λ, λ, and λ, as well as the frame-invariant quantity λ~, are measured from the dimuon decay angular distributions in three different polarization frames. The J/ψ results are obtained in the transverse momentum range 14<p<70 GeV, in the rapidity intervals |y|<0.6 and 0.6<|y|<1.2. The corresponding ψ(2S) results cover 14<p<50 GeV and include a third rapidity bin, 1.2<|y|<1.5. No evidence of large polarizations is seen in these kinematic regions, which extend much beyond those previously explored
Measurement of the differential and double-differential Drell-Yan cross sections in proton-proton collisions at root s=7 TeV
Get PDFMeasurements of the differential and double-differential Drell-Yan cross sections are presented using an integrated luminosity of 4.5 (4.8) fb−1 in the dimuon (dielectron) channel of proton-proton collision data recorded with the CMS detector at the LHC at s√ = 7 TeV. The measured inclusive cross section in the Z-peak region (60–120 GeV) is σ(ℓℓ) = 986.4 ± 0.6 (stat.) ± 5.9 (exp. syst.) ± 21.7 (th. syst.) ± 21.7 (lum.) pb for the combination of the dimuon and dielectron channels. Differential cross sections dσ/dm for the dimuon, dielectron, and combined channels are measured in the mass range 15 to 1500 GeV and corrected to the full phase space. Results are also presented for the measurement of the double-differential cross section d2σ/dm d|y| in the dimuon channel over the mass range 20 to 1500 GeV and absolute dimuon rapidity from 0 to 2.4. These measurements are compared to the predictions of perturbative QCD calculations at next-to-leading and next-to-next-to-leading orders using various sets of parton distribution functions
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