1,429 research outputs found
Syntheses, Structures, and Electroluminescence of New Blue/Green Luminescent Chelate Compounds: Zn(2-py-in)<sub>2</sub>(THF), BPh<sub>2</sub>(2-py-in), Be(2-py-in)<sub>2</sub>, and BPh<sub>2</sub>(2-py-aza) [2-py-in = 2-(2-pyridyl)indole; 2-py-aza = 2-(2-pyridyl)-7-azaindole]
No full textFour novel blue/green luminescent compounds, Zn(2-py-in)2(THF) (1), BPh2(2-py-in) (2), Be(2-py-in)2 (3), and BPh2(2-py-aza) (4), where 2-py-in = 2-(2-pyridyl)indole and 2-py-aza = 2-(2-pyridyl)-7-azaindole, have been synthesized and fully characterized. The 2-py-in ligand and 2-py-aza ligand in the new
compounds are chelated to the central atom. Compounds 2−4 are air stable and readily sublimable, with a
melting point above 250 °C. In the solid state, compounds 1−4 have an emission maximum at λ 488, 516,
490, and 476 nm, respectively. The structures of compounds 2 and 4 are similar. The blue shift of emission
energy displayed by compound 4, in comparison to that of 2, is attributed to the presence of an extra nitrogen
atom in the 2-py-aza ligand as confirmed by ab initio calculations on compounds 2 and 4. Electroluminescent
devices of compounds 3 and 4 were fabricated by using N,N‘-di-1-naphthyl-N,N‘-diphenylbenzidine (NPB) as
the hole transporting layer, Alq3 (q = 8-hydroxyquinolato) as the electron transporting layer, and compound
3 or 4 as the light emitting layer. At 20 mA/cm2 the EL device of 3 has an external efficiency of 1.06 cd/A
while the EL device of 4 has an external efficiency of 2.34 cd/A, demonstrating that compounds 3 and 4 are
efficient and promising emitters in electroluminescent devices
Control of dTTP pool size by anaphase promoting complex/cyclosome is essential for the maintenance of genetic stability
No full textCarbonic anhydrase II deficiency syndrome)osteopetrosis with renal tubular acidosis and brain calcification):Novel mutations in CA2 identified by direct sequencing expand the opportunity for genotype-phenotype correlation
No full textSeven novel mutation in carbonic anhydrase II deficiency syndrome identified by SSCP and direct sequencing analysis
No full textSeven novel mutation in carbonic anhydrase II deficiency syndrome identified by SSCP and direct sequencing analysis
No full textClinical and histological changes of a free radial forearm flap transplanted into the oral cavity- a case report
No full textEnhanced outdoor visual localization using Py-Net voting segmentation approach
Full text linkCamera relocalization determines the position and orientation of a camera in a 3D space. Althouh methods based on scene coordinate regression yield highly accurate results in indoor scenes, they exhibit poor performance in outdoor scenarios due to their large scale and increased complexity. A visual localization method, Py-Net, is therefore proposed herein. Py-Net is based on voting segmentation and comprises a main encoder containing Py-layer and two branch decoders. The Py-layer comprises pyramid convolution and 1 × 1 convolution kernels for feature extraction across multiple levels, with fewer parameters to enhance the model’s ability to extract scene information. Coordinate attention was added at the end of the encoder for feature correction, which improved the model robustness to interference. To prevent the feature loss caused by repetitive structures and low-texture images in the scene, deep over-parameterized convolution modules were incorporated into the seg and vote decoders. Landmark segmentation and voting maps were used to establish the relation between images and landmarks in 3D space, reducing anomalies and achieving high precision with a small number of landmarks. The experimental results show that, in multiple outdoor scenes, Py-Net achieves lower distance and angle errors compared to existing methods. Additionally, compared to VS-Net, which also uses a voting segmentation structure, Py-Net reduces the number of parameters by 31.85% and decreases the model size from 236MB to 170 MB
Microstrain in pyrope-grossular garnet solid solution at high pressure: a case study of Py(90)Gr(10) and Py(10)Gr(90) up to 15 GPa
No full textSingle-phase, well-sintered, translucent polycrystalline garnets with compositions of Py(90)Gr(10) and Py(10)Gr(90) were synthesized at 6 GPa and 1400 degrees C using a multi-anvil apparatus. X-ray diffraction (XRD) data for these garnet solid solutions were collected with both high-resolution synchrotron X-ray and standard laboratory X-ray sources. Analysis of the FWHM of the XRD peaks using Williamson-Hall plot yields microstrains around 0.12% for Py(90)Gr(10) and 0.09% for Py(10)Gr(90). The FWHM of Py(10)Gr(90) garnet as well as the derived microstrain remains constant up to 11 GPa, followed by a continuous increase to the experimental peak pressure 15 GPa caused by elastic strain in response to deviatoric/anisotropic stresses. The FWHM and microstrain for Py(90)Gr(10) remain constant to the measurement limit at 7 GPa. The microstrain of pyrope-grossular garnets exhibits a nonlinear dependence on composition, showing two peaks near Py(20)Gr(80) and Py(80)Gr(20), which may be associated with local structural heterogeneities arising from Mg and Ca substitution. Using a third-order Birch-Murnaghan equation of state, the bulk modulus is constrained to be Ie (0) = 171.8 +/- 2.1 GPa (with K-0(') fixed to 5.92) for Py(10)Gr(90) and Ie (0) = 174.3 +/- 2.5 GPa (with K-0(') fixed to 4.4) for Py(90)Gr(10), both of which are much larger than that for intermediate composition close to Py(50)Gr(50) but comparable to that for their corresponding end members. The relatively larger microstrain and higher bulk moduli for Py(10)Gr(90) and Py(90)Gr(10) garnets could be related to short-range ordering of Mg and Ca cations in garnet structure due to substitution, which results in different local environments for Mg and Ca cations along the pyrope-grossular solid solution.DOE/NNSA [DE-NA0002907]; NSF [EAR1524078]SCI(E)ARTICLE6377-3884
Single-Photon Ionization Induced New Covalent Bond Formation in Acrylonitrile(AN)Pyrrole(Py) Clusters
No full textThe formation of nitrogen-containing organic compounds
is crucial
for understanding chemical evolution and the origin of life in the
interstellar medium (ISM). In this study, we explore whether acrylonitrile
(AN) and pyrrole (Py) can form new nitrogen-containing compounds after
single-photon ionization in their gaseous clusters by vacuum ultraviolet
(VUV)-infrared (IR) spectroscopy and theoretical calculations. The
results show that a strong linear H-bond is formed in neutral AN-Py,
while cyclic or bicyclic H-bonded networks are formed in the neutral
AN-Py2 cluster. It is found that the structure containing
a new C–C covalent bond between two moieties in (AN-Py)+ is formed besides the formation of H-bonded structures after
AN-Py is ionized by VUV light. In (AN-Py2)+ cluster
cations, new C–C or C–N covalent bonds tend to be formed
between two Py, with (Py)2+ as the core in the
cluster. The results reveal that new covalent bonds are more likely
to be formed between two Py species when AN and Py are present in
the cationic clusters. These results provide spectroscopic evidence
of the formation of new nitrogen-containing organic compounds from
AN and Py induced by VUV, which are helpful for our understanding
of the formation of diverse prebiotic molecules in interstellar space
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