Possible Habitats for NH_(3),NH_(2)D,H^(13)CN,HC^(15)N,SO,and C^(18)O in the Initial Conditions of High-mass Star Formation

The initial condition of high-mass star formation is a complex area of study because of the high densities(n_(H_(2))>106cm^(-3))and low temperatures(T_(dust)<18 K)involved.Under such conditions,many molecules become depleted from the gas phase by freezing out onto dust grains.However,the N-bearing and deuterated species could remain gaseous under these extreme conditions,suggesting that they may serve as ideal tracers.In this paper,using the Plateau de Bure Interferometer and Very Large Array observations at 1.3 mm,3.5 mm,and 1.3 cm,we investigate the possible habitats for NH_(3),NH_(2)D,H^(13)CN,HC^(15)N,SO,and C^(18)O in eight massive precluster and protocluster clumps G18.17,G18.21,G23.97N,G23.98,G23.44,G23.97S,G25.38,and G25.71.We found that the NH3cores are in good agreement with the 3.5 mm peak emission,but the NH_(3)is much more extended than the 3.5 mm emission structure.The SO distributions agree well with the 3.5 mm peaks for the evolved star formation stage,but we did not detect any SO emission in the four earliest star formation sources.C^(18)O is a poor tracer in conditions of the cold(■18 K)and dense(■10^(4)cm^(-3))cores,e.g.,the prestellar cores.We also found that the NH_(2)D cores are mainly located in the temperature range of 13.0-20.0 K,and the NH_(2)D lines may be strongly depleted above 20 K.

Implementation of FPGA Based MPPT Techniques for Grid-Connected PV System

Global energy demand is growing rapidly owing to industrial growth and urbanization.Alternative energy sources are driven by limited reserves and rapid depletion of conventional energy sources(e.g.,fossil fuels).Solar photovol-taic(PV),as a source of electricity,has grown in popularity over the last few dec-ades because of their clean,noise-free,low-maintenance,and abundant availability of solar energy.There are two types of maximum power point track-ing(MPPT)techniques:classical and evolutionary algorithm-based techniques.Precise and less complex perturb and observe(P&O)and incremental conduc-tance(INC)approaches are extensively employed among classical techniques.This study used afield-programmable gate array(FPGA)-based hardware arrange-ment for a grid-connected photovoltaic(PV)system.The PV panels,MPPT con-trollers,and battery management systems are all components of the proposed system.In the developed hardware prototype,various modes of operation of the grid-connected PV system were examined using P&O and incremental con-ductance MPPT approaches.

Detecting HI Galaxies with Deep Neural Networks in the Presence of Radio Frequency Interference

In the neutral hydrogen(H I)galaxy survey,a significant challenge is to identify and extract the H I galaxy signal from the observational data contaminated by radio frequency interference(RFI).For a drift-scan survey,or more generally a survey of a spatially continuous region,in the time-ordered spectral data,the H I galaxies and RFI all appear as regions that extend an area in the time-frequency waterfall plot,so the extraction of the H I galaxies and RFI from such data can be regarded as an image segmentation problem,and machine-learning methods can be applied to solve such problems.In this study,we develop a method to effectively detect and extract signals of H I galaxies based on a Mask R-CNN network combined with the PointRend method.By simulating FAST-observed galaxy signals and potential RFI impact,we created a realistic data set for the training and testing of our neural network.We compared five different architectures and selected the best-performing one.This architecture successfully performs instance segmentation of H I galaxy signals in the RFI-contaminated time-ordered data,achieving a precision of 98.64%and a recall of 93.59%.

The Chromatic Point-spread Function of Weak Lensing Measurement in the Chinese Space Station Survey Telescope

Weak gravitational lensing is a powerful tool in modern cosmology.To accurately measure the weak lensing signal,one has to control the systematic bias on a small level.One of the most difficult problems is how to correct the smearing effect of the Point-Spread Function(PSF)on the shape of the galaxies.The chromaticity of PSF for a broad-band observation can lead to new subtle effects.Since the PSF is wavelength-dependent and the spectrum energy distributions between stars and galaxies are different,the effective PSF measured from the star images will be different from those that smear the galaxies.Such a bias is called color bias.We estimate it in the optical bands of the Chinese Space Station Survey Telescope from simulated PSFs,and show the dependence on the color and redshift of the galaxies.Moreover,due to the spatial variation of spectra over the galaxy image,another higher-order bias exists:color gradient bias.Our results show that both color bias and color gradient bias are generally below 0.1%in CSST.Only for small-size galaxies,one needs to be careful about the color gradient bias in the weak lensing analysis using CSST data.

Fabrication of a model specimen for understanding micro-galvanic corrosion at the boundary ofα-Mg andβ-Mg17Al12

A model specimen with a single boundary of theα/βphase simulating Mg-Al alloys was successfully fabricated by spark plasma sintering.A small electrode area ofαphase orβphase was prepared using the model specimen,and the OCPs(open-circuit potentials)of each phase and a small electrode area containing theα/βphase boundary in 0.1 M NaCl at pH 8.0 were compared:theβphase exhibited a higher potential,and theαphase showed a lower potential.The OCP of the small area containing theα/βphase boundary was the intermediate value of these phases.In a small area containingα/βphase boundary,discoloration and gas bubbles were observed on theαphase,but no bubble generation was detected on theβphase.The gas bubbles were initially generated on theαphase near theβphase,but as the discoloration(corrosion)of theαphase approached theβphase,the bubbles were generated on theβphase.In micro-galvanic corrosion of theαandβphases,theβphase did not always function as the preferred cathode.Theαphase partially corroded(or discolored)and became the anodes,so that the surrounding areas were most likely to be the cathodes.When corroded areas(anodes)in theαphase approached theβphase,theβphase would become cathodes.In addition to the micro-galvanic corrosion mechanism,the role of Al in corrosion resistance at theα/βphase boundary was determined by surface analysis.

A Simulation of Calibration and Map-making Errors of the Tianlai Cylinder Pathfinder Array

The Tianlai cylinder array is a pathfinder for developing and testing 21 cm intensity mapping techniques.In this paper,we use numerical simulation to assess how its measurement is affected by thermal noise and the errors in calibration and map-making process,and the error in the sky map reconstructed from a drift scan survey.Here we consider only the single frequency,unpolarized case.The beam is modeled by fitting to the electromagnetic simulation of the antenna,and the variations of the complex gains of the array elements are modeled by Gaussian processes.Mock visibility data are generated and run through our data processing pipeline.We find that the accuracy of the current calibration is limited primarily by the absolute calibration,where the error comes mainly from the approximation of a single dominating point source.We then studied the m-mode map-making with the help of Moore-Penrose inverse.We find that discarding modes with singular values smaller than a threshold could generate visible artifacts in the map.The impacts of the residue variation of the complex gain and thermal noise are also investigated.The thermal noise in the map varies with latitude,being minimum at the latitude passing through the zenith of the telescope.The angular power spectrum of the reconstructed map show that the current Tianlai cylinder pathfinder,which has a shorter maximum baseline length in the North-South direction,can measure modes up to l■2πb_(NS)/λ~200 very well,but would lose a significant fraction of higher angular modes when noise is present.These results help us to identify the main limiting factors in our current array configuration and data analysis procedure,and suggest that the performance can be improved by reconfiguration of the array feed positions.

Robust Fault Detection and Isolation Based on Finite-frequency H__/H_∞ Unknown Input Observers and Zonotopic Threshold Analysis

This work proposes a robust fault detection and isolation scheme for discrete-time systems subject to actuator faults,in which a bank of H_/H∞ fault detection unknown input observers(UIOs) and a zonotopic threshold analysis strategy are considered. In observer design, finite-frequency H_ index based on the generalized Kalman-Yakubovich-Popov lemma and H∞ technique are utilized to evaluate worst-case fault sensitivity and disturbance attenuation performance, respectively. The proposed H_/H∞ fault detection observers are designed to be insensitive to the corresponding actuator fault only, but sensitive to others.Then, to overcome the weakness of predefining threshold for FDI decision-making, this work proposes a zonotopic threshold analysis method to evaluate the generated residuals. The FDI decision-making relies on the evaluation with a dynamical zonotopic threshold. Finally, numerical simulations are provided to show the feasibility of the proposed scheme.

MPPT Design Using PSO Technique for Photovoltaic System Control Comparing to Fuzzy Logic and P&O Controllers

The Maximum Power Point Tracker (MPPT) is the optimum operating point of a photovoltaic module. It plays a very important role to obtain the maximum power of a solar panel as it allows an optimal use of a photovoltaic system, regardless of irradiation and temperature variations. In this research, we present a novel technique to improve the control’s performances optimization of the system consisting of a photovoltaic panel, a buck converter and a load. Simulations of different parts of the system are developed under Matlab/Simulink, thus allowing a comparison between the performances of the three studied controllers: “Fuzzy TS”, “P&O” and “PSO”. The three algorithms of MPPT associated with these techniques are tested in different meteorological conditions. The obtained results, in different operating conditions, reveal a clear improvement of controlling performances of MPPT of a photovoltaic system when the PSO tracking technique is used.

Manifestations of bright points observed in G-band and CaⅡH by Hinode/SOT

An algorithm was developed for identifying and tracking a magnetic bright point, or bright point （BP） for short, observed in both the photosphere （G-band） and chromosphere （Ca II H）, as well as for pairing a photospheric BP （PBP） with its conjugate chromospheric BP （CBP）. Two sets of data observed by Hinode/SOT in the quiet Sun near the disk center were analyzed. About 278 PBP-CBP pairs were identified and tracked. Lifetimes of both the PBPs and CBPs follow an exponential distribution with average lifetimes of 174 s and 163 s, respectively. We found that the differences in appearance time, in disappearance time and in lifetime of the two kinds of BPs all follow Gaussian distributions,which may indicate that the mechanisms of PBP and CBP formation/disintegration are different. However, the lifetimes of PBPs and CBPs are positively correlated with one another, with a correlation coefficient of 0.8. Furthermore, we calculated the horizontal displacement between the PBP and its conjugate CBP, which follows a Gaussian function with an average and standard deviation of （67.7 ± 38.5）km. We also calculated the amplitude of the flux tube shape change which might be caused by MHD waves propagating along the flux tube, and found that it follows an exponential distribution very well.

中医理筋正骨手法配合Ponseti方法治疗低龄小儿先天性马蹄内翻足临床观察

目的:研究中医理筋正骨手法配合Ponseti方法治疗低龄小儿先天性马蹄内翻足的临床疗效。方法:将60例诊断为低龄小儿先天性马蹄内翻足患儿,随机分为观察组和对照组,各30例。观察组采用中医理筋正骨手法配合Ponseti方法治疗,对照组单用Ponseti方法治疗。观察和比较2组患儿的踝关节被动跖屈度、跟腱延长长度和临床疗效。结果:治疗后3、6、12、24个月,2组患儿的踝关节跖屈度、跟腱延长长度较治疗前明显改善(P<0.05),且观察组改善效果优于对照组(P<0.05)。2组在各时间段均具有临床疗效,且观察组均优于对照组(P<0.05)。结论:采用中医理筋正骨手法配合Ponseti方法治疗低龄小儿先天性马蹄内翻足,能够延长患足跟腱长度,增大患足跖屈度,矫正马蹄内翻畸形,疗效显著,值得临床推广。

DOPS在静脉采血技术考核中的应用实践

目的探索医学检验技术实训考核中合适的客观评价方法。方法以医学检验技术专业核心技能静脉采血技术为例,采用操作技能直接观察评估(DOPS)为评量工具,设计DOPS评量表和评价标准,DOPS评量表评分设计一般采用6级分法,1~2分为未达到标准,3分为接近标准,4分为达到标准,5~6分为超过标准。对96名医学检验技术学生在岗前训练前进行操作强化培训,使用DOPS评量工具考核。结果经过培训考核,所有学生达到预期考核目标,99.0%的学生认为DOPS考核有助于对核心技能的掌握;100.0%的同学一致认可DOPS及时有效的反馈形式;95.8%的学生认为DOPS考核可以培养自己积极的学习态度,提高自主学习的能力。结论 DOPS促进了教师和学生之间的良性互动,既有助于学生找到自己实训操作中的薄弱环节,又促使教师不断完善实训教学计划。因此,DOPS评价方法可以提高学生的临床技能的学习效果及操作水平。

“observe”病情观察技术在临床应用中的效果评价

目的:探讨应用"observe"病情观察技术在临床中的应用及效果评价。方法:随机将168名护士分为实验组(84名)和对照组(84名),对应实验组和对照组患者各90例。对照组予患者施行传统的护理观察技术,实验组予患者施行"observe"技术,即对患者生命体征、临床表现、临床生化检查、引流管及药物的应用等的评判性观察能力的培训。比较两组护士的理论操作考核成绩和两组患者抢救时间、成功率、死亡率、并发症后遗症、护理缺陷、入住ICU时间、费用指标。结果:(1)培训完毕,针对基础理论、危急值知识、引流管知识、药理知识、急救技术、护理记录问题发生率及护理缺陷发生率进行了理论考试,考核成绩显示实验组明显优于对照组,差异有统计学意义(P﹤0.05);(2)比较实验组和对照组患者的抢救时间、抢救成功率、死亡率、并发症发生率、护理缺陷发生率、入住ICU时间、医疗费用等指标,显示实验组优于对照组,差异有统计学意义(P﹤0.05)。结论:"observe"病情观察技术是确保疾病转归良好的有效技能。

Re-POT技术在经皮冠状动脉介入分叉病变双支架术式中的应用

目的探讨两次近段优化(Re-POT)技术在经皮冠状动脉介入(PCI)分叉病变双支架术式中的应用效果。方法选取2018年1月-2019年9月拟在丰城市人民医院行PCI治疗的110例冠状动脉分叉病变患者,按手术方式不同分为观察组(55例)和对照组(55例)。对照组行常规双支架挤压(crush)/裙裤(Culotte)术式治疗,观察组行改良的Re-POT技术治疗,比较2组手术效果、术后血管再狭窄率、术后心血管不良事件发生率和心脏超声结果。结果2组手术成功率均为100%,观察组对吻球囊扩张(KBI)成功率高于对照组,手术时间短于对照组,造影剂使用量、住院费用、术后血管再狭窄率和心血管不良事件发生率均低于对照组,差异有统计学意义(P<0.05);2组术后3个月和12个月左心房内径(LAD)、左心室舒张末期内径(LVEDd)低于术前,左心室射血分数(LVEF)高于术前,且观察组LAD、LVEDd低于对照组,LVEF高于对照组,差异有统计学意义(P<0.05)。结论在冠状动脉分叉病变患者PCI中使用Re-POT技术能够缩短手术用时,提高KBI成功率,减少造影剂使用,改善心功能,减少心血管不良事件、血管再狭窄率发生,利于减轻患者经济负担。

A new multi-wavelength solar telescope: Optical and Near-infrared Solar Eruption Tracer (ONSET)

A new multi-wavelength solar telescope, the Optical and Near-infrared Solar Eruption Tracer （ONSET） of Nanjing University, has been constructed. It was fabricated at the Nanjing Institute of Astronomical Optics ＆ Technology, and the oper- ation is jointly administered with Yunnan Astronomical Observatory. ONSET is able to observe the Sun in three wavelength windows： He I 10830 A, Ha and white-light at 3600 A and 4250 A, which are selected in order to simultaneously record the dynam- ics of the corona, chromosphere and photosphere respectively. Full-disk or partial-disk solar images with a field of 10~ at three wavelengths can be obtained nearly simultane- ously. It is designed to trace solar eruptions with high spatial and temporal resolutions. This telescope was installed at a new solar observing site near Fuxian Lake in Yunnan Province, southwest China. The site is located at E102N24, with an altitude of 1722 m. The seeing is stable and has high quality. We give a brief description of the scientific objectives and the basic structure of ONSET. Some preliminary results are also pre- sented.

Recent Progress in Atmospheric Observation Research in China

Recent progress in atmospheric observation techniques, observational systems and their application in China are reviewed. According to different observational platforms, the review is presented in three sections, i.e., satellite remote sensing （SRS）, ground-based observation technologies and applications, and aircraft/balloon measurements. The section ＂satellite remote sensing＂ presents advances in SRS techniques, SRS of clouds and aerosols, and SRS of trace gases and temperature/moisture profiles. The section ＂groundbased observation technologies and applications＂ focuses on research such as lidar systems and applications, sun/sky radiometer and broadband radiation observations, weather radar and wind profilers, GPS measurements, and some new concept systems. The section ＂aircraft/balloon measurements＂ presents some newly developed aircraft- and balloon-based sounding techniques.

Portable adaptive optics for exoplanet imaging

The portable adaptive optics(PAO)device is a low-cost and compact system,designed for 4-meter class telescopes that have no adaptive optics(AO)system,because of the physical space limitation at the Nasmyth or Cassegrain focus and the historically high cost of conventional AO.The initial scientific observations of the PAO are focused on the direct imaging of exoplanets and sub-stellar companions.This paper discusses the concept of PAO and the associated high-contrast imaging performance in our recent observational runs.PAO deliver a Strehl ratio better than 60%in H band under median seeing conditions of 1".Combined with our dedicated image rotation and subtraction(IRS)technique and the optimized IRS(O-IRS)algorithm,the averaged contrast ratio for a 5≤V_(mag)≤9 primary star is 1.3×10^(-5)and3.3×10^(-6)at angular distance of 0.36"with exposure time of 7 minutes and 2 hours,respectively.PAO has successfully revealed the known exoplanet ofκAnd b in our recent observation with the 3.5-meter ARC telescope at Apache Point Observatory.We have performed the associated astrometry and photometry analysis of the recoveredκAnd b planet,which gives a projected separation of 0.98"±0.05",a position angle of 51.1°±0.5°and a mass of 10.15_(-1.255)^(+2.19) MJup.These results demonstrate that PAO can be used for direct imaging of exoplanets with medium-sized telescopes.

基于变长观察法载波同步的OQPSK全数字解调器

在应用于非协同通信的自适应盲接收机系统中,OQPSK信号的解调是一个难点。本文通过对数字同步技术的研究,提出了一种新的OQPSK全数字解调器。该解调器能够在恶劣信号条件下对OQPSK信号进行解调,对Eb/N0、载波频偏、时钟偏差等有很大的宽容度。本文在解调器数字锁相环的研究中提出了“变长观察法”,很好地解决了数字锁相环频率捕捉范围和相位稳定度对观察长度不同要求之间的矛盾,从而显著扩大了低Eb/N0 条件下数字锁相环的频率捕捉范围。

Particle swarm optimization based space debris surveillance network scheduling

The increasing number of space debris has created an orbital debris environment that poses increasing impact risks to existing space systems and human space flights. For the safety of in-orbit spacecrafts, we should optimally schedule surveillance tasks for the existing facilities to allocate re- sources in a manner that most significantly improves the ability to predict and detect events involving affected spacecrafts. This paper analyzes two criteria that mainly affect the performance of a scheduling scheme and introduces an artificial intelligence algorithm into the scheduling of tasks of the space debris surveillance network. A new scheduling algorithm based on the particle swarm optimization algorithm is proposed, which can be implemented in two different ways： individual optimization and joint optimiza- tion. Numerical experiments with multiple facilities and objects are conducted based on the proposed algorithm, and simulation results have demonstrated the effectiveness of the proposed algorithm.

Distributed Robust Containment Control of Linear Heterogeneous Multi-Agent Systems:An Output Regulation Approach

In this paper,we consider the robust output containment problem of linear heterogeneous multi-agent systems under fixed directed networks.A distributed dynamic observer based on the leaders’measurable output was designed to estimate a convex combination of the leaders’states.First,for the case of followers with identical state dimensions,distributed dynamic state and output feedback control laws were designed based on the state-coupled item and the internal model compensator to drive the uncertain followers into the leaders’convex hull within the output regulation framework.Subsequently,we extended theoretical results to the case where followers have nonidentical state dimensions.By establishing virtual errors between the dynamic observer and followers,a new distributed dynamic output feedback control law was constructed using only the states of the compensator to solve the robust output containment problem.Finally,two numerical simulations verified the effectiveness of the designed schemes.