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Journal of Rare Earths 2010年第5期28卷 760-764页

作者： Umesh Chand Kamlesh Yadav Anurag gaur varma g d department of Physics Indian Institute of Technology department of Physics National Institute of Technology

We investigated the effect of different synthesis techniques on the structural, magnetic and magneto-transport properties of Pr0.7Sr0.3MnO3 (PSMO) samples. The samples were synthesized by three different techniques: solid state reaction, sol-gel and chemical Co-precipitation method. XRd studies confirmed the single phase formation of PSMO by all three techniques. It was also found that the magnetotransport properties of PSMO strongly depended on the synthesis techniques. A substantial decrease in the insula...

关键词： magnetoresistance electrical transport grain boundary rare earths

Wetting of MXenes and Beyond

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Nano-Micro Letters 2023年第8期15卷 141-153页

作者： Massoud Malaki Rajender S.varma department of Mechanical Engineering Isfahan University of TechnologyDaneshgah e Sanati HwyKhomeyni ShahrIsfahan 84156‑83111Iran Regional Centre of Advanced Technologies and Materials Palacky University in OlomoucŠlechtitelů2778371 OlomoucCzech Republic

MXenes are a class of 2d nanomaterials with exceptional tailormade properties such as mechano-ceramic nature,rich chemistry,and hydrophilicity,to name a ***,one of the most challenging issues in any composite/hybrid system is the interfacial *** a superior integrity of a given composite system is a direct consequence of the proper *** wetting is a fundamental feature,dictating many physical and chemical attributes,most of the common nanomaterials possesses poor affinity due to hydrophobic nature,making them hard to be easily dispersed in a given *** to low contact angle,MXenes can offer themselves as an ideal candidate for manufacturing different nano-hybrid *** this review,it is aimed to particularly study the wettability of *** terms of the layout of the present study,MXenes are first briefly introduced,and then,the wettability phenomenon is discussed in *** reviewing the sporadic research efforts conducted to date,a particular attention is paid on the current challenges and research pitfalls to light up the future *** is strongly believed that taking the advantage of MXene’s rich hydrophilic surface may have a revolutionizing role in the fabrication of advanced materials with exceptional features.

关键词： MXene Wetting Hydrophilicity Composites 2d material

Water and nutrient recovery from urine:A lead up trail using nano-structured In_(2)S_(3)photo electrodes

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Chinese Physics B 2021年第5期30卷 531-535页

作者： R Jayakrishnan T R Sreerev Adith varma department of Physics University of KeralaThiruvananthapuramKerala 695581India Photovoltaic Research Laboratory Christian College Chenagnnur 689122India

developments of economic systems are critical for bio-regenerative life support systems in manned space *** this work we report on the feasibility of using two direct sunlight powered processes sequentially for the recovery of water and nutrients from *** work presents experimental evidence on nutrient and water recovery achieved using the proto-type designed and *** report the design and testing of a solar still which would serve on the nutrient recovery *** cooled condensate from the solar still is fed into a solar powered electrolysis unit where nano-structured indium sulphide(In_(2)S_(3))thin films coated over fluorine doped tin oxide(SnO_(2):F)substrate serve as one of the working *** electrolysis takes place in the absence of an electrolyte which manifests as a technical achievement of our *** results show that the COd level in the recycled water is very *** In_(2)S_(3)photo-electrodes are stable without any physical damage after the process.

关键词： semiconductors water quality thin film structure and morphology electrolysis

Nitration of Jharia basin coals,India:a study of structural modifications by XRd and FTIR techniques

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International Journal of Coal Science & Technology 2021年第5期8卷 1034-1053页

作者： Prabal Boral Atul K.varma Sudip Maity CSIR-Central Institute of Mining and Fuel Research PO:FRIDhanbad 828108India department of Applied geology Indian Institute of Technology(ISM)Dhanbad826004India

Four coal samples from Jharia basin,India are treated with nitric acid in glacial acetic acid and aqueous media to find out the chemical,petrographic and spatial structure of the organic mass by X-ray diffraction(XRd)and Fourier Transform Infrared Spectroscopy(FTIR)techniques.X-ray parameters of coal like interlayer spacing(d_(002)),crystallite size(L_(c)),aroamticity(f_(a)),average number of aromatic layers(N_(c)),and coal rank(I_(26)/I_(20))have been determined using profilefitting *** variation is observed in treated coals in comparison to the demineralized *** d_(002)values of treated coals have increased in both the media showing increase in disordering of organic moieties.A linear relationship has been observed between d_(002)values with the volatile matter of the ***,the d_(002)values show linear relationship with C_(dmf) contents for demineralized as well as for the treated coals in both the *** L_(c) and N_(c) values have decreased in treated coals corresponding to demineralized *** present study shows that nitration in both the media is capable of removing the aliphatic side chains from the coals and aromaticity(f_(a))increases with increase in rank and shows a linear relationship with the vitrinite *** corresponding I_(26)/I_(20)values are least for treated coals in glacial acetic acid medium followed by raw and then to treated coals in aqueous *** studies show that coal arenes of the raw coals are converted into nitro-arenes in structurally modified coals(SMCs)in both the media,the corresponding bands at 1550-1490 and 1355-1315 cm^(-1) *** study confirms that nitration is the predominant phenomenon,though,oxidation and nitration phenomena takes place simultaneously during treatment with nitric acid to form *** comparison to raw coals,the SMCs show higher aromaticity and may be easily converted to coal derived products like activated carbon and specialty carbon materials

关键词： Coal Micro-structure Nitration XRd FTIR

Effect of nano-and micron-sized K0.5Na0.5NbO3 fillers on the dielectric and piezoelectric properties of PVdF composites

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Journal of Advanced Ceramics 2016年第4期5卷 92-页

作者： Bharathi PONRAJ Rajasekhar BHIMIREddI K.B.R.varma Materials Research Centre Indian Institute of Science Bangalore-560012 India

Polymer nanocrystal composites were fabricated by embedding polyvinylidene fluoride (PVdF) with K0.5Na0.5NbO3 (KNN) nanocrystallites of different volume fraction using the hot-pressing *** comparison,PVdF-KNN microcrystal composites of the same compositions were also fabricated which facilitated the studies of the crystallite size (wide range) effect on the dielectric and piezoelectric *** structural,morphological,dielectric,and piezoelectric properties of these nano and micro crystal composites were *** incorporation of KNN fillers in PVdF at both nanometer and micron scales above 10 vol％ resulted in the formation of polar β-form of *** room temperature dielectric constant as high as 3273 at 100 Hz was obtained for the PVdF comprising 40 vol％ KNN nanocrystallites due to dipole-dipole interactions (as the presence of β-PVdF is prominent),whereas it was only 236 for the PVdF containing the same amount (40 vol％) of micron-sized crystallites of KNN at the same *** theoretical models were employed to predict the dielectric constants of the PVdF-KNN nano and micro crystal *** PVdF comprising 70 vol％ micron-sized crystallites of KNN exhibited a d33 value of 35 pC/N,while the nanocrystal composites of PVdF-KNN did not exhibit any piezoelectric response perhaps due to the unrelieved internal stress within each grain,besides the fact that they have less domain walls.

关键词： polyvinylidene fluoride (PVdF) K0.5Na0.5NbO3 (KNN) composites β-PVdF nanocrystallites

Relief from vascular occlusion using photothermal ablation of tlhrombus with a multimodal perspective

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Nano Research 2016年第8期9卷 2327-2337页

作者： Nitesh Singh Anand varma Ashish Verma Babu N. Maurya debabrata dash department of Biochemistry Institute of Medical Sciences Banaras Hindu University Varanasi 221005 India department of Radiodiagnosis and Imaging Institute of Medical Sciences Banaras Hindu University Varanasi 221005 India

Fibrinolytic therapy for arterial or venous thrombotic disorders involves the systemic administration of thrombolytics such as streptokinase, which is associated with serious bleeding complications. With this study, we provide a proof-of-concept of photothermal thrombus ablation with gold nanorods exposed to near-infrared irradiation, both in vitro using materials generated from purified fibrinogen or plasma and in vivo in murine blood vessels. This is the first report of the application of photothermal therapy as an anti-thrombotic measure. Remarkably, the addition of streptokinase had a multimodal additive effect with regard to acceleration of photothermal lysis of thrombi even at a dose significantly below the therapeutic concentration, thus minimizing the life- threatening side effects and adverse complications. This combinatorial approach exhibits great promise for lysing pathological clots while effectively overcoming the drawbacks of existing therapies.

关键词： platelet fibrin near-infrared laser photothermal therapy thrombolysis streptokinase

Superconductivity in the cuprates： deduction of mechanism for d-wave pairing through analysis of ARPES

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Frontiers of physics 2011年第4期6卷 440-449页

作者： Han-Yong Choi Chandra M. varma Xing-jiang Zhou department of Physics and Institute for Basic Science Research Sung Kyun Kwan University Suwon 440-746 Korea department of Physics and Astronomy University of California Riverside California 92521 USA National Laboratory for Superconductivity Institute of Physics Chinese Academy of Sciences Beijing 100190 China

In the Eliashberg integral equations for d-wave superconductivity, two different functions （α2F）n（ω, θ） and （α2F）p,d（ω） determine, respectively, the ＂normal＂ self-energy and the ＂pairing＂ self-energy, w is the frequency of fluctuations scattering the fermions whose momentum is near the Fermi-surface and makes an angle θ to a chosen axis. We present a quantitative analysis of the high-resolution laser based Angle Resolved Photoemission Spectroscopy （ARPES） data on a slightly under doped cuprate compound Bi2212 and use the Eliashberg equations to deduce the w and dependence of （α2F）n（ω, θ） for T just above Tc and below Tc. Besides its detailed w dependence, we find the remarkable result that this function is nearly independent of θ between the （π; π）-direction and 25 degrees from it, except for the dependence of the cut-off energy on 8. Assuming that the same fluctuations determine both the normal and the pairing self-energy, we ask what theories give the function （α2F）p,d（ω） required for the d-wave pairing instability at high temperatures as well as the deduced （α2F）n（θ, w）. We show that the deduced （α2F）n（θ, w） can only be obtained from antiferromagnetic （AFM） fluctuations if their correlation length is smaller than a lattice constant. Using （α2F）p,d（W） consistent with such a correlation length and the symmetry of matrix-elements scatter- ing fermions by AFM fluctuations, we calculate Tc and show that AFM fluctuations are excluded as the pairing mechanism for d-wave superconductivity in cuprates. We also consider the quantumcritical fluctuations derived microscopically as the fluctuations of the observed loop-current order discovered in the under-doped cuprates, and which lead to the marginal Fermi-liquid properties in the normal state. We show that their frequency dependence and the momentum dependence of their matrix-elements to scatter fermions are consistent with the θ and w dependence of the deduced （α2F）n（ω, θ）. The pairing kernel （α2F）p,d（W） calculated using

关键词： high temperature superconductivity mechanisms of superconductivity

Polytene chromosomes of an Indian Himalayan black fly Simulium (Nevermannia) praelargum (diptera:Simuliidae)

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Current Zoology 2010年第4期56卷 437-444页

作者： Willie HENRY Subrata Kumar dEY Rakesh varma Sachin THAPA William S PROCUNIER Rg. department of Zoology Darjeeling Government College Darjeeling West Bengal 734101 India School of Biotechnology West Bengal University of TechnologyBF-142 Sector 1Salt Lake City Kolkata 700064 West Bengal India Consultant North Bay Ontario P1B 5W6 Canada

High quality polytene chromosome maps （n=3） of a Himalayan Simuliid Simulium praelargum datta, 1973 are presented and represent the first cytological description of a taxon found in the feuerborni group, subgenus Nevermannia. Polytene chromosomes one （I） and two （II） are metacentric, chromosome three （III） is submetacentric with the length of each chromosome occupying 37.25 %, 31.36 % and 31.34 % of the total complement length, respectively. Typical simuliid diagnostic intergeneric chromosomal markers are found within the polytene complement of this species. The nucleolar organizer （N.O.） is found at the base of the short arm of chromosome one （IS）, the Ring of Balbiani （R.B.）, double bubble （d.B.） and triad occur in the short arm of chromosome two （IIS）, the Parabalbiani Ring （EB.） and grey band （gb） occur in the long arm of chromosome two （IIL） and the Blister （BL） and Capsule （Ca） occur in the short arm of chromosome three （IIIS）.Terminal bands at the end of IIIS are heterochromatinized and present atypically with respect to other simuliid fauna. Populations studied so far are unique among the Simuliidae in that they exhibit chromosome structural monomorphism. These high resolution polytene chromosome maps will form the basis for future cytological characterization and phylogenetic comparisons amongst members of the feuerborni group

关键词： Black fly Feuerborni group Simulium praelargum Polytene chromosome maps Monomorphism

Measurement and comparison of gas holdup in Rushtontank at higher impeller speeds and larger gas fluxes with γ-CT

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Measurement and comparison of gas holdup in Rushtontank at h...

An adaptive supervised wide-area backup protection scheme for transmission lines protection

第三届全国化学工程与生物化工年会

作者： Shaibal Roy Rajneesh varma CREL department of Chemical Engineering Washington University in St．LouisMOUSA63130 CREL department of Chemical Engineering Washington University in St．LouisMOUSA63130

＜正＞Three gas dispersion states in liquid in a standard Rushton stirred tank（20cm i.d.）-cup dispersion, critical dispersion and full dispersion were observed in experiments for air-water system. Only those gas dispersion states over the critical dispersion were of significations both in laboratory researches and in industrial applications. However this situation couldn’t be distinguished in the flow map regime established on gas-filled cavity structures usually used to judge gas dispersion states in liquid in Rushton stirred tank. The distributions of gas holdups at 3/4 dimensionless static liquid height of tank

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Protection and Control of Modern Power Systems 2017年第1期2卷 229-244页

作者： B.Mallikarjuna P.V.Vardhan varma S.d.Samir M.Jaya Bharata Reddy d.K.Mohanta department of Electrical and Electronics Engineering National Institute of TechnologyTiruchirappalliTamilnaduIndia. department of Electrical and Electronics Engineering Birla Institute of TechnologyMesraRanchiIndia.

Maloperation of conventional relays is becoming prevalent due to ever increase in complexity of conventional power *** are dominant during power system contingencies like power swing,load encroachment,voltage instability,unbalanced loading,*** these situations,adaptive supervised wide-area backup protection(ASWABP)plays a major role in enhancing the power system reliability.A balance between security and dependability of protection is essential to maintain the *** paper proposes multi-phasor measurement units(MPMU)based ASWABP scheme that can function effectively during faults besides power system *** is an extended version of Phasor Measurement Unit(PMU).It is an intelligent electronic device which estimates the synchronized predominant harmonic phasors(100Hz and 150Hz)along with the fundamental phasors(50Hz)of three phase voltages and currents with high *** proposed ASWABP scheme can detect the fault,identify the parent bus,determine the faulty branch and classify the faults using MPMU measurements at System Protection Center(SPC).Based on these MPMU measurements(received at phasor data concentrator(PdC)at SPC)the appropriate relays will be supervised to enhance the overall reliability of the power *** case studies are conducted on WSCC-9 bus and IEEE-14 bus systems to illustrate the security and dependability attributes of proposed ASWABP scheme in MATLAB/Simulink ***,comparative studies are performed with the existing conventional distance protection(Mho relays)for corroborating the superiority of the proposed scheme regarding security and *** studies have shown that the proposed scheme can be used as adaptive supervised wide-area backup protection of conventional distance protection.

关键词： Adaptive supervised wide-area backup protection(ASWABP) Multi-phasor measurement unit(MPMU) Security dependability