599 research outputs found
Statistically study the optimal local sources for cosmic ray nuclei and electron
The local sources, such as Geminga SNR, may play important role for the
anomaly of proton, electron and anisotropy in the past works. In fact, there
exists twelve SNRs around solar system within kpc. One question is that can
other SNRs also possibly contribute the spectra of nuclei and electron and
explain the special structure of anisotropy? In this work, under the
spatial-dependent propagation, we systematically study the contribution of all
local SNRs within 1 kpc around solar to the spectra of nuclei and electron, as
well as the energy dependence of anisotropy. As a result, only Geminga,
Monogem, and Vela SNRs have quantitive contribution to the nuclei and electron
spectra and anisotropy. Here, Geminga SNR is the sole optimal candidate and
Monogem SNR is controversial due to the tension of anisotropy between model
calculation and observations. The Vela SNR contributes a new spectral structure
beyond TeV energy, hinted by HESS, VERITAS, DAMPE and CALET measurements. More
interesting is that the electron anisotropy satisfies the Fermi-LAT limit below
TeV energy, but rises greatly and reaches at several TeV. This new
structure will shed new light to check our model. We hope that the new
structure of electron spectrum and anisotropy can be observed by space-borne
DAMPE and HERD and ground-based HAWC and LHAASO experiments in the near future.Comment: 11 pages, 8 figures, accepted by AP
A new understanding of nuclei spectra properties with propagation model
The AMS-02 experiment has observed new properties of primary cosmic rays
(CRs) categorized into two groups: He-C-O-Fe and Ne-Mg-Si-S, which are
independent of CR propagation. In this study, we investigate the unexpected
properties of these nuclei using a spatial propagation model. All nuclei
spectra are accurately reproduced and separated into primary and secondary
contributions. Our findings include: 1. Primary CR spectra are identical. 2.
Our calculations align with AMS-02 results for primary-dominated nuclei within
a 10\% difference, but show significant discrepancies for the
secondary-dominated nuclei. 3. The primary element abundance is presented for
the first time. We anticipate that the DAMPE and future HERD experiments will
provide observations of nuclei spectra above TeV energy.Comment: 8 pages, 8 figures. accepted by PR
Risk for Gestational Diabetes Mellitus and Adverse Birth Outcomes in Chinese Women with Polycystic Ovary Syndrome
Objective. To examine the association of polycystic ovary syndrome (PCOS) in early pregnancy with gestational diabetes mellitus (GDM) and adverse birth outcomes. Methods. In this retrospective cohort study including 2389 pregnant women, the medical records of 352 women diagnosed with PCOS were evaluated. Outcomes included GDM, preterm birth, low birth weight, macrosomia, and being small and large for gestational age. Multivariable logistic regression models were used to examine the association of the risk for GDM and adverse birth outcomes with PCOS after adjusting for confounders. Results. Women previously diagnosed with PCOS had a higher risk of GDM (adjusted odds ratio [OR] 1.55, 95% confidence interval [CI]: 1.14–2.09). A strong association was seen between PCOS and preterm birth (adjusted OR 1.69, 95% CI: 1.08–2.67). On stratified analysis, the adjusted OR for GDM among women with PCOS undergoing assisted reproductive technology was 1.44 (95% CI: 1.03–1.92) and among women with PCOS who conceived spontaneously was 1.60 (1.18–2.15). No increased risk for other adverse birth outcomes was observed. Conclusions. Women with PCOS were more likely to experience GDM and preterm birth
Mobile defects as mediated states for charge-carrier trapping in metal halide perovskites quantum dots
The migration motion of defects in metal halide perovskites quantum dots
(MHPQDs) results in charge-carrier trapping become more complicated. We study
two-step trapping mediated by mobile defects between the ground state of MHPQDs
and a fixed-depth defect using a full-configuration defect method, where all
possible trapping processes mediated by these mobile defects could be
reproduced and the fastest channels among them are picked out. We find that
these two-step trapping processes could keep more one order of magnitude faster
than these direct ones as mobile defect with the appropriate localization
strength, which implies that these indirect trapping should play the crucial
rule to determine the non-radiative recombination losses. These results provide
the significant explanation for studying non-radiation processes of carriers in
the presence of the migration defects in recent experiments. Moreover, this
model will be available to analyze some key performance related defects in
electronic devices.Comment: 5 pages, 3 figure
Microscopic theory of Raman scattering for the rotational organic cation in metal halide perovskites
A gap exists in microscopic understanding the dynamic properties of the
rotational organic cation (ROC) in the inorganic framework of the metal halide
perovskites (MHP) to date. Herein, we develop a microscopic theory of Raman
scattering for the ROC in MHP based on the angular momentum of a ROC exchanging
with that of the photon and phonon. We systematically present the selection
rules for the angular momentum transfer among three lowest rotational levels.
We find that the phonon angular momentum that arising from the inorganic
framework and its specific values could be directly manifested by Stokes (or
anti-Stokes) shift. Moreover, the initial orientation of the ROC and its
preferentially rotational directions could be judged in Raman spectra. This
study lays the theoretical foundation for the high-precision resolution and
manipulation of molecular rotation immersed in many-body environment by Raman
technique
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