752 research outputs found
3,3-Diphenyl-2-Morpholinone Derivatives Of 2-Amino-2-Deoxy-D-Allose.
A new cyclic protective group has been fused to the cis amino alcohol group of benzyl 2-amino-3,5-o-benzylidene-2-deoxyβ-D-Allopyranoside, by way of a unique rearrangements mechanism. To establish the 2-morpholinone structure, chemical studies, such as reduction and acetylation were conducted.
Comparative spectroscopic studies using ir, pmr, and C-13 nmr confirmed the assigned structures.
The 2-morpholinone ring was cleaved by mild alkaline hydrolysis and could be closed again with acetic anhydride in pyridine. An oxazolidinone derivation of benzyl 2-amino-4,6-o-benzylidene-2-deoxyβ-D-allopyranoside was prepared in a quantitative yield by a modification of a known method.
Protective group properties of the oxazolidinone were studied prior to the examination of the 2-morpholinone cyclic protective group. The selective removal of the benzyl aqlycon was achieved in excellent yield by catalytic hydrogenation, for both morpholinone and oxazolidinone protected benzyl-β-D-Allopyranoside. The selective removal of the 4,6-o-benzylidone group in presence of a 2-morpholinone ring was possible in high yield. The cleavage of the 2-morpholinone protective group was accomplished in two steps. Mild alkaline hydrolysis cleaved the ester function of the ring and mild acidic hydrolysis cleaved its amino function
High-spin triaxial strongly deformed structures and quasiparticle alignments in 168Hf
This dissertation research consists of two parts: (i) investigation of quasiparticle alignments at high-spins and (ii) identification of triaxial strongly deformed structures in 168Hf. A γ-ray spectroscopy study was carried out, as well as lifetime measurements using the Doppler-shift Attenuation Method (DSAM). The two data sets used for this research were obtained from experiments at Argonne National Laboratory employing the reaction 96Zr(76Ge, 4n). The decay γ-rays were measured with the Gammasphere Compton-suppressed Ge spectrometer array. A self-supporting 96Zr foil ( thin target ) was used in the first experiment, while in the second experiment the 96Zr target material was evaporated onto a thick Au backing ( backed target or thick target ) to stop the recoiling nuclei for lifetime measurements. All previously known rotational bands have been extended to higher spins. Seven new normal-deformed bands, of which three are high-K bands, have been discovered. Neutron alignments were observed in all bands, and the proton alignments observed in several bands at the highest spin region (rotational frequency 0.55 - 0.6 MeV). The results are interpreted within the framework of the cranked shell model (CSM). Intrinsic configurations for the new bands, up to six quasiparticles, are proposed. The co-existing coupling schemes, deformation and rotation alignment, involving identical orbitals at high spin are discussed for the high-K bands. Possible decay pathways associated with three previously proposed candidates for triaxial strongly deformed (TSD) structures in 168Hf have been investigated. The spin and excitation energy of the bandhead for the strongest band, TSD1, were determined approximately based on γ-ray coincidence relationships. Discrete links were established for the second band. The overall agreement between the observed properties of the bands and cranking calculations using the Ultimate Cranker code provides strong support for an interpretation where band TSD1 is associated with a TSD minimum, (ε2, γ) ~ (0.43, 20°), involving the π(i13/2)2 and the ν(j15/2) high-j orbitals. This constitutes the first identification of a TSD band in Hf isotopes, long-predicted by theoretical studies. The second band is understood as being associated with a near-prolate shape and a deformation enhanced with respect to the normal deformed bands. It is proposed to be built on the π(i13/2 h9/2)ν(i13/2)2 configuration. The Doppler-shift attenuation method was used to measure lifetimes of yrast states. The deformation extracted from this measurement fits well with predictions from theoretical calculations
Diaspora : Dislocation,Development and Drawback
This study focuses on diasporas painful feelings and bitter experiences while they are living in the host land. It stresses on their efforts to maintain connections with people back in their homeland. Besides, the research talks about diasporas's attempt to assimilate, acculturate and integrate in the host countries in their dislocated and unhomely state. the study also explore the changing attitude of intellectuals, writers, journalists and politicians of host countries towards diasporas, that they have recognized diasporas' positive culture and economic contribution to host societies. Gradually and cautiously more host societies and their governments are accepting diaspora members' affiliations as legitimate and sought for their permanence. Moreover, in some host countries, and in liberal circles, membership of in such entities has been regarded as exciting and advantageous but not as an obstacles. Yet, the migrants are backed by criticisms and detriments. They establish networks back in their country of origin and try to influence homeland's politics and sometimes support the violent activities. On top of that, the continued migration and increase in remittances encourage chain of migration and brain drain, and create instability in homeland economics.
High-spin triaxial strongly deformed structures and quasiparticle alignments in 168Hf
This dissertation research consists of two parts: (i) investigation of quasiparticle alignments at high-spins and (ii) identification of triaxial strongly deformed structures in 168Hf. A γ-ray spectroscopy study was carried out, as well as lifetime measurements using the Doppler-shift Attenuation Method (DSAM). The two data sets used for this research were obtained from experiments at Argonne National Laboratory employing the reaction 96Zr(76Ge, 4n). The decay γ-rays were measured with the Gammasphere Compton-suppressed Ge spectrometer array. A self-supporting 96Zr foil ( thin target ) was used in the first experiment, while in the second experiment the 96Zr target material was evaporated onto a thick Au backing ( backed target or thick target ) to stop the recoiling nuclei for lifetime measurements. All previously known rotational bands have been extended to higher spins. Seven new normal-deformed bands, of which three are high-K bands, have been discovered. Neutron alignments were observed in all bands, and the proton alignments observed in several bands at the highest spin region (rotational frequency 0.55 - 0.6 MeV). The results are interpreted within the framework of the cranked shell model (CSM). Intrinsic configurations for the new bands, up to six quasiparticles, are proposed. The co-existing coupling schemes, deformation and rotation alignment, involving identical orbitals at high spin are discussed for the high-K bands. Possible decay pathways associated with three previously proposed candidates for triaxial strongly deformed (TSD) structures in 168Hf have been investigated. The spin and excitation energy of the bandhead for the strongest band, TSD1, were determined approximately based on γ-ray coincidence relationships. Discrete links were established for the second band. The overall agreement between the observed properties of the bands and cranking calculations using the Ultimate Cranker code provides strong support for an interpretation where band TSD1 is associated with a TSD minimum, (ε2, γ) ~ (0.43, 20°), involving the π(i13/2)2 and the ν(j15/2) high-j orbitals. This constitutes the first identification of a TSD band in Hf isotopes, long-predicted by theoretical studies. The second band is understood as being associated with a near-prolate shape and a deformation enhanced with respect to the normal deformed bands. It is proposed to be built on the π(i13/2 h9/2)ν(i13/2)2 configuration. The Doppler-shift attenuation method was used to measure lifetimes of yrast states. The deformation extracted from this measurement fits well with predictions from theoretical calculations
DeepFuse: A Deep Unsupervised Approach for Exposure Fusion with Extreme Exposure Image Pairs
We present a novel deep learning architecture for fusing static
multi-exposure images. Current multi-exposure fusion (MEF) approaches use
hand-crafted features to fuse input sequence. However, the weak hand-crafted
representations are not robust to varying input conditions. Moreover, they
perform poorly for extreme exposure image pairs. Thus, it is highly desirable
to have a method that is robust to varying input conditions and capable of
handling extreme exposure without artifacts. Deep representations have known to
be robust to input conditions and have shown phenomenal performance in a
supervised setting. However, the stumbling block in using deep learning for MEF
was the lack of sufficient training data and an oracle to provide the
ground-truth for supervision. To address the above issues, we have gathered a
large dataset of multi-exposure image stacks for training and to circumvent the
need for ground truth images, we propose an unsupervised deep learning
framework for MEF utilizing a no-reference quality metric as loss function. The
proposed approach uses a novel CNN architecture trained to learn the fusion
operation without reference ground truth image. The model fuses a set of common
low level features extracted from each image to generate artifact-free
perceptually pleasing results. We perform extensive quantitative and
qualitative evaluation and show that the proposed technique outperforms
existing state-of-the-art approaches for a variety of natural images.Comment: ICCV 201
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