The In-Flight Realtime Trigger and Localization Software of GECAM

Realtime trigger and localization of bursts are the key functions of GECAM,an all-sky gamma-ray monitor launched on 2020 December 10.We developed a multifunctional trigger and localization software operating in the CPU of the GECAM Electronic Box.This onboard software has the following features:high trigger efficiency for real celestial bursts with a suppression of false triggers caused by charged particle bursts and background fluctuation,dedicated localization algorithm optimized for both short and long bursts,and low time latency of the trigger information which is downlinked through the Global Short Message Communication service of the global BeiDou navigation system.This paper provides a detailed description of the design and development of the trigger and localization software system for GECAM.It covers the general design,workflow,the main functions,and the algorithms used in the system.The paper also includes on-ground trigger tests using simulated gamma-ray bursts generated by a dedicated X-ray tube,as well as an overview of the performance for real celestial bursts during its in-orbit operation.

3D-Slicer软件在神经内镜经鼻蝶入路垂体腺瘤手术中的应用

目的探讨3D-Slicer软件辅助神经内镜经鼻蝶入路垂体腺瘤手术的疗效与价值。方法28例垂体腺瘤患者行头颅CT和头颅MRI检查,将影像数据输入3D-Slicer软件,对蝶窦、鞍区骨性结构、垂体腺瘤及颈内动脉、视神经结构进行三维重建,并行术前规划,判断神经血管和肿瘤的空间关系,模拟磨除鞍底的过程,将重建图像与术中图像进行比较,评价两者吻合程度,记录术后并发症和疗效。结果所有患者的三维重建图像中,蝶窦、鞍区骨性结构、垂体腺瘤及神经血管均可清晰显示,与术中内镜下实际图像高度匹配,能准确识别重要结构,并规划出鞍底骨窗的合适范围。所有患者手术过程顺利,术后均未发生严重并发症。结论3D-Slicer软件运用于神经内镜下经鼻蝶入路垂体腺瘤手术,有助于术前明确显示蝶窦、蝶鞍、肿瘤与神经血管的空间关系,可帮助提高手术安全性与手术效率。

Simulation of GaN micro-structured neutron detectors for improving electrical properties

Nowadays,the superior detection performance of semiconductor neutron detectors is a challenging task.In this paper,we deal with a novel GaN micro-structured neutron detector(GaN-MSND)and compare three different methods such as the method of modulating the trench depth,the method of introducing dielectric layer and p-type inversion region to improve the width of depletion region(W).It is observed that the intensity of electric field can be modulated by scaling the trench depth.On the other hand,the electron blocking region is formed in the detector enveloped with a dielectric layer.Furthermore,the introducing of p-type inversion region produces new p/n junction,which not only promotes the further expansion of the depletion region but also reduces the intensity of electric field produced by main junction.It can be realized that all these methods can considerably enhance the working voltage as well as W.Of them,the improvement on W of GaN-MSND with the p-type inversion region is the most significant and the value of W could reach 12.8μm when the carrier concentration of p-type inversion region is 10^17 cm^-3.Consequently,the value of W is observed to improve 200%for the designed GaN-MSND as compared with that without additional design.This work ensures to the researchers and scientific community the fabrication of GaN-MSND having superior detection limit in the field of intense radiation.

Effect of Au/Ni/4H–SiC Schottky junction thermal stability on performance of alpha particle detection

Au/Ni/n-type 4H-SiC Schottky alpha particle detectors are fabricated and annealed at temperatures between 400℃ and 700 ℃ to investigate the effects of thermal stability of the Schottky contact on the structural and electrical properties of the detectors. At the annealing temperature of 500 ℃, the two nickel silicides （i.e., Ni31Sil2 and Ni2Si） are formed at the interface and result in the formation of an inhomogeneous Schottky barrier. By increasing the annealing temperature, the Ni31Sil2 transforms into the more stable Ni2Si. The structural evolution of the Schottky contact directly affects the electrical properties and alpha particle energy resolutions of the detectors. A better energy resolution of 2.60% is obtained for 5.48-MeV alpha particles with the detector after being annealed at 600 ℃. As a result, the Au/Ni/n-type 4H-SiC Schottky detector shows a good performance after thermal treatment at temperatures up to 700℃.

Design and performance study of the HEPP-H calorimeter onboard the CSES satellite

The China Seismo-Electromagnetic Satellite(CSES) will investigate iono-magnetospheric disturbance and will monitor the temporal stability of the inner Van Allen radiation belts.In particular,the mission aims at confirming the existences of a temporal correlation between the occurrence of earthquakes and the observation of electromagnetic disturbances, plasma fluctuations and anomalous fluxes of high-energy particles precipitating from the inner Van Allen belt in space.The high energy detector of the High Energy Particle Package(HEPP-H) is a payload onboard CSES and is designed for detecting electrons(2–50 MeV) and protons(20–200 MeV) in its 500 km orbit above Earth.CSES was launched in February 2018.In this paper, the instrumentation and development of the HEPP-H calorimeter are described.The calibration with beam particles(electrons and protons) is discussed in detail.

Timing analysis of the black hole candidate EXO 1846–031 with Insight-HXMT monitoring

We present the observational results from a detailed timing analysis of the black hole candidate EXO 1846-031 during its outburst in 2019 with the observations of Insight-HXMT,NICER and MAXI.This outburst can be classified roughly into four different states.Type-C quasi-periodic oscillations(QPOs)observed by NICER(about 0.1-6 Hz)and Insight-HXMT(about 0.7-8 Hz)are also reported in this work.Meanwhile,we study various physical quantities related to QPO frequency.The QPO rms-frequency relationship in the energy band 1-10 keV indicates that there is a turning pointing in frequency around2 Hz,which is similar to that of GRS 1915+105.A possible hypothesis for the relationship above may be related to the inclination of the source,which may require a high inclination to explain it.The relationships between QPO frequency and QPO rms,hardness,total fractional rms and count rate have also been found in other transient sources,which can indicate that the origin of type-C QPOs is non-thermal.

Effects of policies and containment measures on control of COVID- 19 epidemic in Chongqing

BACKGROUND Coronavirus disease 2019(COVID-19)is an emerging,rapidly evolving disease that spreads through the respiratory system and is highly contagious.In March 2020,the World Health Organization declared the COVID-19 outbreak a pandemic.In China,the pandemic was controlled after 2 mo through effective policies and containment measures.Describing the detailed policies and containment measures used to control the epidemic in Chongqing will provide a reference for the prevention and control of COVID-19 in other areas of the world.AIM To explore the effects of different policies and containment measures on the control of the COVID-19 epidemic in Chongqing.METHODS Epidemiological data on COVID-19 in Chongqing were prospectively collected from January 21 to March 15,2020.The policies and prevention measures implemented by the government during the epidemic period were also collected.Trend analysis was performed to explore the impact of the main policy measures on the effectiveness of the control of COVID-19 in Chongqing.As of March 15,the cumulative incidence of COVID-19 in Chongqing was 1.84/100000(576 cases)and the infection fatality rate was 1.04%(6/576).The spread of COVID-19 was controlled by effective policies that involved establishing a group for directing the COVID-19 epidemic control effort;strengthening guidance and supervision;ensuring the supply of daily necessities and medical supplies and equipment to residents;setting up designated hospitals;implementing legal measures;and enhancing health education.Medical techniques were implemented to improve the recovery rate and control the epidemic.Policies such as“the lockdown of Wuhan”,“initiating a first-level response to major public health emergencies”,and“implementing the closed management of residential communities”significantly curbed the spread of COVID-19.Optimizing the diagnosis process,shortening the diagnosis time,and constructing teams of clinical experts facilitated the provision of“one team of medical experts for each patient”treatment for severe patients,which significantly improved the recovery rate and reduced the infection fatality rate.CONCLUSION The prevention policies and containment measures implemented by the government and medical institutions are highly effective in controlling the spread of the epidemic and increasing the recovery rate of COVID-19 patients.

Relationship between quality of life and adolescent glycolipid metabolism disorder:A cohort study

BACKGROUND The prevalence of glucolipid metabolic disorders(GLMDs)in children and adolescents has a recognized association with cardiovascular diseases and type 2 diabetes mellitus in adulthood.Therefore,it is important to enhance our understanding of the risk factors for GLMD in childhood and adolescence.AIM To explore the relationship between quality of life(QoL)and adolescent GLMD.METHODS This study included 1956 samples in 2019 from a cohort study established in 2014.The QoL scale and glycolipid indexes were collected during follow-up;other covariates of perinatal factors,physical measures,and socioeconomic indicators were collected and adjusted.A generalized linear regression model and logistic regression model were used to analyse the correlation between QoL and GLMD.RESULTS Higher scores of QoL activity opportunity,learning ability and attitude,attitude towards doing homework,and living convenience domains correlated negatively with insulin and homeostasis model assessment insulin resistance(IR)levels.Psychosocial factors,QoL satisfaction factors,and total QoL scores had significant protective effects on insulin and IR levels.Activity opportunity,learning ability and attitude,attitude towards doing homework domains of QoL,psychosocial factor,and total score of QoL correlated positively with high density lipoprotein.In addition,the attitude towards doing homework domain was a protective factor for dyslipidaemia,IR>3,and increased fasting blood glucose;four factors,QoL and total QoL score correlated significantly negatively with IR>3.In subgroup analyses of sex,more domains of QoL correlated with insulin and triglyceride levels,dyslipidaemia,and IR>3 in females.Poor QoL was associated with an increased prevalence of GLMD,and the effect was more pronounced in males than in females.Measures to improve the QoL of adolescents are essential to reduce rates of GLMD.CONCLUSION Our study revealed that QoL scores mainly correlate negatively with the prevalence of GLMD in adolescents of the healthy population.The independent relationship between QoL and GLMD can be illustrated by adjusting for multiple covariates that may be associated with glycaemic index.In addition,among females,more QoL domains are associated with glycaemic index.

Paired quasi-periodic pulsations of hard X-ray emission in a solar flare

We investigate high time resolution data obtained by the Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor(GECAM)during the flare event on 2022 April 21 at 01:52 UT.Several subpeaks with durations of 4-6 s have been detected in the hard X-ray precursor phase,and the key feature is that they appear in pairs and seem like double-peak struc-tures.These subpeaks are rarely observed in hard X-ray band and confirmed by the microwave obtained by Nobeyama Radio Polarimeters(NoRP)and Radio Solar Telescope Network(RSTN).While an exponential function can describe the continuum component of the time profile from the precursor to part of the impulsive phase.The periods of quasi-periodic pulsations(QPPs)are detected to be about 7.3 and 12.8 s for the precursor and impulsive phase,respectively,with at least 95%confidence level.The paired QPPs are assumed to be double-peak QPPs and then the scenario of current loop coalescence model is found to be in good agreement with our observation.The precursor phase can be interpreted as the oscillating coalescence of two islands,while the impulsive phase can be interpreted as more islands to coalesce one by one to form larger islands.