2,131 research outputs found
Dynamic absorption of carbon dioxide on microporous carbons
Adsorption of carbon dioxide on microporous carbon
Study and modification of the reactivity of carbon fibers
The reactivity to air of polyactylonitrile-based carbon fiber cloth was enhanced by the addition of metals to the cloth. The cloth was oxidized in 54 wt% nitric acid in order to increase the surface area of the cloth and to add carbonyl groups to the surface. Metal addition was then achieved by soaking the cloth in metal acetate solution to effect exchange between the metal carbon and hydrogen on the carbonyl groups. The addition of potassium, sodium, calcium and barium enhanced fiber cloth reactivity to air at 573 K. Extended studies using potassium addition showed that success in enhancing fiber cloth reactivity to air depends on: extent of cloth oxidation in nitric acid, time of exchange in potassium acetate solution and the thoroughness of removing metal acetate from the fiber pore structure following exchange. Cloth reactivity increases essentially linearly with increase in potassium addition via exchange
Statistical investigation through stratified random sampling for apple production in Himachal Pradesh
The present study focuses on standardization of sampling technique and comparison of different types of sample allocation methods in combination with various stratification tools (optimum strata boundaries, number of strata and optimum sample size etc.) for obtaining efficient estimators of area and production of apple in Himachal Pradesh. Forth is purpose, various aspects involved in optimum stratification with reference todata collected from the selected or chardists in district Shimla, during the year 2011-12 have been analyzed. The variable "Area under Apple" was chosen as the stratification variable as it had high correlation(r=0.96) with the estimation variable "Production of Apple". Four methods of construction of strata viz., equalization of strata total, equalization of cumulative of ?f(y) , equalization of cumulative of ½{r(y)+f(y)} and equalization of cumulative of were used and their relative efficiencies for estimating total production of apple in the study district of the state have been analyzed. The critical examination of the result revealed that with the increase in number of strata from 2 to 4 and sample size from 10 to 40, equalization of cumulative of method along with Neyman allocation resulted in least variance (0.89) and maximum percentage gain in efficiency (20418.16). Thus, equalization of cumulative of method with L>2 can profitably be applied for the estimation of apple production in the study district of the state Himachal Pradesh, India
Adsorption Isotherms of Carbon Dioxide at 273°K on Adsorbent Carbons & Evaluation of Microporosity using Dubinin Equation
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Genetic divergence evaluation of apple germplasm by D2 multivariate analysis
Genetic divergence was worked out in the new germplasm of apple (Malus × domestica Borkh.) including 42 genotypes. Mahalanobis's D2 statistics was applied for identifying the potential parents to be involved in the hybridization programme for trait specific improvement or selecting better segregants. On the basis of performance for various traits, genotypes were grouped into three clusters and maximum numbers of genotypes i.e. 28 were accommodated in cluster I , while 10 and 4 genotypes were arranged in cluster II and III respectively. The average intra cluster distance was maximum in cluster II (2.214) and minimum in cluster III (1.212). Inter cluster distance was maximum between cluster II and III (5.077) indicating that hybridization between genotypes from cluster II and III can be utilized for getting the superior recombinants in segregating generations. On the basis of cluster means for various characters , cluster II was found superior for shoot thickness (0.34cm), inter - nodal length (2.38cm), number of lenticels (62.10) and leaf blade length (8.79cm) whereas cluster III was found superior for leaf blade width (5.10cm), petiole length (2.64cm) and leaf blade ratio (3.62). Hence, hybridization between parents from cluster II and cluster III for these characters can produce better recombinants in segregating generations
Epigenetic reprogramming of cell cycle genes by ACK1 promotes breast cancer resistance to CDK4/6 inhibitor
Hormone receptor-positive, HER2-negative advanced breast cancers exhibit high sensitivity to CDK4/6 inhibitors such as palbociclib. However, most patients inevitably develop resistance, thus identification of new actionable therapeutic targets to overcome the recurrent disease is an urgent need. Immunohistochemical studies of tissue microarray revealed increased activation of non-receptor tyrosine kinase, ACK1 (also known as TNK2) in most of the breast cancer subtypes, independent of their hormone receptor status. Chromatin immunoprecipitation studies demonstrated that the nuclear target of activated ACK1, pY88-H4 epigenetic marks, were deposited at cell cycle genes, CCNB1, CCNB2 and CDC20, which in turn initiated their efficient transcription. Pharmacological inhibition of ACK1 using its inhibitor, (R)-9b dampened CCNB1, CCNB2 and CDC20 expression, caused G2/M arrest, culminating in regression of palbociclib-resistant breast tumor growth. Further, (R)-9b suppressed expression of CXCR4 receptor, which resulted in significant impairment of metastasis of breast cancer cells to lung. Overall, our pre-clinical data identifies activated ACK1 as an oncogene that epigenetically controls the cell cycle genes governing the G2/M transition in breast cancer cells. ACK1 inhibitor, (R)-9b could be a novel therapeutic option for the breast cancer patients that have developed resistance to CDK4/6 inhibitors
Electronic Structure and Heavy Fermion Behavior in LiV_2O_4
First principles density functional calculations of the electronic and
magnetic properties of spinel-structure LiVO have been performed
using the full potential linearized augmented planewave method. The
calculations show that the electronic structure near the Fermi energy consists
of a manifold of 12 bands derived from V states, weakly hybridized
with O p states. While the total width of this active manifold is approximately
2 eV, it may be roughly decomposed into two groups: high velocity bands and
flatter bands, although these mix in density functional calculations. The flat
bands, which are the more atomic-like lead to a high density of states and
magnetic instability of local moment character. The value of the on-site
exchange energy is sensitive to the exact exchange correlation parameterization
used in the calculations, but is much larger than the interaction between
neighboring spins, reflecting the weak coupling of the magnetic system with the
high velocity bands. A scenario for the observed heavy fermion behavior is
discussed in which conduction electrons in the dispersive bands are weakly
scattered by local moments associated with strongly correlated electrons in the
heavy bands.This is analogous to that in conventional Kondo type heavy
fermions, but is unusual in that both the local moments and conduction
electrons come from the same d-manifold.Comment: 6 Revtex pages, Postscript figs embedded. Revision: figure 4 replaced
with a better version, showing the band character explicitel
Beat-wave generation of plasmons in semiconductor plasmas
It is shown that in semiconductor plasmas, it is possible to generate large
amplitude plasma waves by the beating of two laser beams with frequency
difference close to the plasma frequency. For narrow gap semiconductors (for
example n-type InSb), the system can simulate the physics underlying beat wave
generation in relativistic gaseous plasmas.Comment: 11 pages, LaTex, no figures, no macro
The electronic structure of the heavy fermion metal
The electronic structure of the first reported heavy fermion compound without
f-electrons LiV_2O_4 was studied by an ab-initio calculation method. In the
result of the trigonal splitting and d-d Coulomb interaction one electron of
the configuration of V ion is localized and the rest partially fills
a relatively broad conduction band. The effective Anderson impurity model was
solved by Non-Crossing-Approximation method, leading to an estimation for the
single-site Kondo energy scale T_K. Then, we show how the so-called exhaustion
phenomenon of Nozi\`eres for the Kondo lattice leads to a remarkable decrease
of the heavy-fermion (or coherence) energy scale (D
is the typical bandwidth), comparable to the experimental result.Comment: 4 pages, RevTeX; 3 figures in format .eps. submitted to PR
Impurity in a d-wave superconductor: Kondo effect and STM spectra
We present a theory for recent STM studies of Zn impurities in the
superconductor BSCCO, using insights from NMR experiments which show that there
is a net S=1/2 moment on the Cu ions near the Zn. We argue that the Kondo spin
dynamics of this moment is the origin of the low bias peak in the differential
conductance, rather than a resonance in a purely potential scattering model.
The spatial and energy dependence of the STM spectra of our model can also fit
the experiments.Comment: 4 pages, 2 color figures. Found improved saddle-point with d-wave
correlations near the impurity; onset of Kondo screening now occurs at a
significantly smaller coupling, but there is little qualitative change in
other features. Noted connection to STM of Kondo impurities in normal metals.
Final version as publishe
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