215 research outputs found
High-efficiency photoelectric detector based on a p-n homojunction of monolayer black phosphorus
We numerically investigate the high-efficiency photovoltaic effect in lateral
p-n homojunction based on monolayer black phosphorus (MBP) by using the
non-equilibrium Green's function combined with the density functional theory.
Due to the built-in electric field of the p-n junction and the wrinkle
structure of MBP, the photocurrent excited by either linearly or elliptically
polarized light is significantly enhanced in a wide photon energy range.
Moreover, because of the electron-photon interaction, the photocurrent is
related to atomic orbitals through the polarizing angle of polarized light.
Therefore, we can read the orbital information of the band structure from the
polarizing angular distribution of photocurrent. These findings suggest the
promising application of MBP-based p-n homojunction in high-efficiency
photoelectric devices and orbital-resolved photovoltaic detection
Liver Damage in Patients with HCV/HIV Coinfection Is Linked to HIV-Related Oxidative Stress
HIV infection aggravates the progression of liver damage in HCV-coinfected patients, with the underlying pathogenesis being multifactorial. Although high level of oxidative stress has been observed frequently in patients infected with HIV or HCV, the status of oxidative stress in HIV/HCV coinfection and its contribution to HCV liver damage have not been determined. This study involved 363 HBsAg-negative, anti-HCV-positive former blood donors recruited from a village in central China in July 2005; of these, 140 were positive for HIV. Of these 363 subjects, 282 were successfully followed up through July 2009. HIV/HCV-coinfected subjects had higher rates of end-stage liver disease-related death than those monoinfected with HCV. Liver ultrasound manifestations were poor in HIV-positive than in HIV-negative individuals, in both chronic HCV carriers and those with resolved HCV. Serum concentrations of total glutathione (tGSH), malondialdehyde (MDA), glutathione peroxidase (GSH-Px), GSSG, and reduced GSH were higher in HIV-positive than HIV-negative subjects. GSSG concentrations were higher in HIV-infected subjects with abnormal ALT/AST levels than in those with normal ALT/AST levels and were associated with poorer liver ultrasound manifestations. These finding indicated that HIV infection accelerated HCV-associated liver damage in HIV/HCV-coinfected individuals. Increased oxidative stress, induced primarily by HIV coinfection, may contribute to aggravated liver damage
Construction and Evaluation of Mandarin Multimodal Emotional Speech Database
A multi-modal emotional speech Mandarin database including articulatory
kinematics, acoustics, glottal and facial micro-expressions is designed and
established, which is described in detail from the aspects of corpus design,
subject selection, recording details and data processing. Where signals are
labeled with discrete emotion labels (neutral, happy, pleasant, indifferent,
angry, sad, grief) and dimensional emotion labels (pleasure, arousal,
dominance). In this paper, the validity of dimension annotation is verified by
statistical analysis of dimension annotation data. The SCL-90 scale data of
annotators are verified and combined with PAD annotation data for analysis, so
as to explore the internal relationship between the outlier phenomenon in
annotation and the psychological state of annotators. In order to verify the
speech quality and emotion discrimination of the database, this paper uses 3
basic models of SVM, CNN and DNN to calculate the recognition rate of these
seven emotions. The results show that the average recognition rate of seven
emotions is about 82% when using acoustic data alone. When using glottal data
alone, the average recognition rate is about 72%. Using kinematics data alone,
the average recognition rate also reaches 55.7%. Therefore, the database is of
high quality and can be used as an important source for speech analysis
research, especially for the task of multimodal emotional speech analysis
Semiquantum key distribution using initial states in only one basis without the classical user measuring
From the perspective of resource theory, it is interesting to achieve the
same quantum task using as few quantum resources as possible. Semiquantum key
distribution (SQKD), which allows a quantum user to share a confidential key
with a classical user who prepares and operates qubits in only one basis, is an
important example for studying this issue. To further limit the quantum
resources used by users, in this paper, we constructed the first SQKD protocol
which restricts the quantum user to prepare quantum states in only one basis
and removes the classical user's measurement capability. Furthermore, we prove
that the constructed protocol is unconditionally secure by deriving a key rate
expression of the error rate in the asymptotic scenario. The work of this paper
provides inspiration for achieving quantum superiority with minimal quantum
resources.Comment: 13 pages, 3 figure
Tolerance of transgenic Arabidopsis thaliana overexpressing apple MdAGO4.1 gene to drought and salt stress
The regulatory role of apple MdAGO4.1 gene in plant drought and salt resistance is unclear. In this study, transgenic A. thaliana in which the apple MdAGO4.1 gene was over-expressed was used to analyze the regulatory effects of the MdAGO4.1 gene on plant drought and salt resistance, to verify the function of the apple MdAGO4.1 gene. The seed germination rate, seedling fresh weight and root length of transgenic Arabidopsis strains in MS medium containing different concentrations of NaCl and mannitol were better than those of the wild type. The transgenic A. thaliana seedlings were more resistant to drought than wild type under drought stress. The transgenic strains were less affected by salt stress than thewild type. Exposure to drought and salt stress reduced the relative elektrolyte leakage, malondialdehyde (MDA), superoxide anion (O2-), and hydrogen peroxide (H2O2) levels of the transgenic strain significantly compared with the levels in the wild type. The levels of proline, protective enzyme activities, and the expression of genes related to drought and salt stress resistance were significantly higher than those of the wild type. These results indicate that MdAGO4.1 overexpression improved drought and salt tolerance in transgenic Arabidopsis. This study can provide a theoretical basis for future research on stress tolerance mechanisms and breeding new varieties of fruit trees resistant to drought and salt
Plasma beam dumps for the EuPRAXIA facility
Beam dumps are indispensable components for particle accelerator facilities to absorb or dispose beam kinetic energy in a safe way. However, the design of beam dumps based on conventional technology, i.e., energy deposition via beam–dense matter interaction, makes the beam dump facility complicated and large in size, partly due to the high beam intensities and energies achieved. In addition, specific methods are needed to address the radioactive hazards that these high-power beams generate. On the other hand, the European Plasma Research Accelerator with eXcellence in Application (EuPRAXIA) project can advance the laser–plasma accelerator significantly by achieving a 1–5 GeV high-quality electron beam in a compact layout. Nevertheless, beam dumps based on the conventional technique will still produce radiation hazards and make the overall footprint less compact. Here, a plasma beam dump will be implemented to absorb the kinetic energy from the EuPRAXIA beam. In doing so, the overall compactness of the EuPRAXIA layout could be further improved, and the radioactivity generated by the facility can be mitigated. In this paper, results from particle-in-cell simulations are presented for plasma beam dumps based on EuPRAXIA beam parameters
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