An experimental review of open heavy flavor and quarkonium production at RHIC

Open heavy flavors and quarkonia are unique probes of the hot–dense medium produced in heavy-ion collisions. Their production in p+p collisions also constitutes an important test of QCD. In this paper, we review selected results on the open heavy flavors and quarkonia generated in the p+p and heavy-ion collisions at the Relativistic Heavy Ion Collider. The physical implications are also discussed.

OCTA检测高度近视患者视网膜脉络膜厚度及血流变化的研究进展

高度近视是指近视度数在-6.00D以上的一种屈光不正状态。由于高度近视常常伴随多种眼底病理性改变,因此高度近视患者的视功能受到不同程度损害。光学相干断层扫描血管成像(OCTA)作为一种新兴的眼科辅助检查手段,可以高效、无创地得到视网膜、脉络膜的微血管分层图像,并对血流信号进行量化分析。自OCTA问世以来,运用OCTA观察高度近视眼底改变的研究层出不穷。本文通过对OCTA检测高度近视患者视网膜脉络膜厚度及血流变化的研究现状进行综述,以期揭示高度近视与视网膜脉络膜厚度、血流密度以及中心凹无血管区面积等参数的相关性,为科研人员深入探索高度近视发生机制,延缓高度近视发生发展提供思路。

Multiplicity dependence of charged particle,? meson, and multistrange particle productions in p + p collisions at s^(1/2) = 200 GeV from PYTHIA simulation

We report the multiplicity dependence of charged particle production for the n~±, K~±, p, , and ? mesons at |y|<1:0 in p + p collisions at s^(1/2) = 200 GeV from a PYTHIA simulation. The impact of multiple parton interactions and gluon contributions is studied and found to be a possible source of the splitting of the particle yields as a function of p_T with respect to the multiplicity. No obvious particle species dependence of the splitting is observed.The multiplicity dependence of the ratios Kˉ/πˉ, K^+/π^+,/πˉ, p/π^+, and K_s^0 at mid-rapidity in p+ p collisions is found to follow a tendency similar to that in Au t Au collisions at (s_(NN))^(1/2) = 200 GeV at the Relativistic Heavy Ion Collider, indicating similar underlying initial production mechanisms despite the differences in the initial colliding systems.

Non-extensive statistical distributions of charmed meson production in Pb-Pb and pp(p)collisions

The mid-rapidity transverse momentum spectra of charmed mesons in Pb–Pb and pp(p)collisions are analyzed using the Tsallis–Pareto distribution derived from non-extensive statistics.We provide uniform descriptions of both small and large systems over a wide range of collision energies and hadron transverse momenta.By establishing the relationship between the event multiplicity and Tsallis parameters,we observe that there is a signifi-cant linear relationship between the thermal temperature and Tsallis q parameter in Pb–Pb collisions at √sNN=2.76 TeV and 5.02 TeV.Further,the slope of the T–(q-1)parameter plot is positively correlated with the hadron mass.In addition,charmed mesons have a higher thermal temperature than light hadrons at the same q-1,indicat-ing that the charm flavor requires a higher temperature to reach the same degree of non-extensivity as light flavors in heavy-ion collisions.The same fit is applied to the trans-verse momentum spectra of charmed mesons in pp(p)collisions over a large energy range using the Tsallis–Pareto distribution.It is found that the thermal temperature increases with system energy,whereas the q parameter becomes saturated at the pp(p)limit,q-1=0.142±0.010.In addition,the results of most peripheral Pb–Pb collisions are found to approach the pp(p)limit,which suggests that more peripheral heavy-ion collisions are less affected by the medium and more similar to pp(p)collisions.

Extraction of inclusive photon production at mid-rapidity in p+p and Au+Au collisions at√SNN=200GeV

We present a comprehensive study on the individual sources of an inclusive photon production during high-energy hadronic collisions.The cross section and invariant yields of inclusive photons are obtained as a function of pT at mid-rapidity(|y|<0.5)in p+p and Au+Au collisions at√SNN=200GeVrespectively.These results provide crucial inputs to separate measurements of open bottom and charm hadron yield suppression in heavyion collisions,which are used to test the mass hierarchy of the parton energy loss in the quark gluon plasma created during these collisions.The procedure developed in this study can also be applied to other measurements of electrons from an open heavy-flavor hadron decay,such as the collective flow in the RHIC beam energy scan program.

Region coverage control for multiple stratospheric airships with combined self-/event-triggered mechanism

The region coverage control problem of multiple stratospheric airships system is firstly addressed in this paper.Towards it,we propose a two-layer control framework with the artificial potential field(APF)-based region coverage control law and the adaptive tracking control law.The APF-based region coverage control law ensures the coverage task is achieved until every single stratospheric airship ends up performing station keeping where near the respective global minimum point,in which an innovative solution to the local minimum problem is put forward.The adaptive tracking control law is designed to realize motion control using tracking the desired velocity and angular velocity given by coverage control law,with the consideration of several practical control problems as unknown individual differences and external disturbances.To save resources,the combined self-/event-triggered mechanism designed therein significantly reduces the times of state information transmission and control law calculation.The effectiveness of the proposed control framework is verified through simulations.

基于伏邪理论探讨幽门螺旋杆菌感染

幽门螺旋杆菌是临床常见感染之一。本文通过梳理古今伏邪相关理论,并将伏邪理论与现代感染病学知识进行联系,得出伏邪与幽门螺旋杆菌都具有潜伏性、消耗性、复发性等特性;伏邪的发病和幽门螺旋杆菌的感染都与机体正邪状态相关;伏邪“直中”胃腑与幽门螺旋杆菌经消化道感染的发病方式相类似等结论。探讨幽门螺旋杆菌与伏邪的关系可为中医学深入认识及防治幽门螺旋杆菌相关性疾病提供新的诊疗思路。

Cleaning of carbon-contaminated optics using O2/Ar plasma

Cleaning of carbon-contaminated beamline optics was studied by RF plasma discharge process using O_2/Ar. Carbon-coated samples were prepared, and through their cleaning processes key parameters were determined,such as the optimal RF output power, mixing rates of O_2/Ar, and chamber vacuum. Considerations were made against possible adverse effects in cleaning the beamline optics, such as comparing the roughness of samples before and after cleaning, and possible detrimental kinetic effects on cable insulation. Under the cleaning parameters to clean the beamline optics, the thickness of removed carbon film and the change in beamline photon flux were analyzed.

Fabrication and characterization of Al–Mn superconducting films for applications in TES bolometers

Superconducting transition edge sensor(TES)bolometers require superconducting films to have controllable transition temperatures T_(c)in different practical applications.The value of T_(c)strongly affects thermal conductivity and thermal noise performance of TES detectors.Al films doped with Mn(Al-Mn)of different concentrations can accomplish tunable T_(c)A magnetron sputtering machine is used to deposit the Al-Mn films in this study.Fabrication parameters including sputtering pressure and annealing process are studied and their influences on T_(c)and superconducting transition widthΔT_(c)are optimized.The Al-Mn films withΔT_(c)below 1.0 mK for T_(c)in a range of 520 mK-580 mK are successfully fabricated.

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.

Applying the Kalman filter particle method to strange and open charm hadron reconstruction in the STAR experiment

We applied KF Particle, a Kalman Filter package for secondary vertex finding and fitting, to strange and open charm hadron reconstruction in heavy-ion collisions in the STAR experiment. Compared to the conventional helix swimming method used in STAR, the KF Particle method considerably improved the reconstructed Λ, Ω, and D~0 significance. In addition, the Monte Carlo simulation with STAR detector responses could adequately reproduce the topological variable distributions reconstructed in real data using the KF Particle method, thereby retaining substantial control of the reconstruction efficiency uncertainties for strange and open charm hadron measurements in heavy-ion collisions.

ASICla contributes to the symptom of pain in a ra＇ model of chronic prostatitis

This study aims to validate our hypothesis that acid-sensing ion channels （ASICs） may contribute to the symptom of pain in patients with chronic prostatitis （CP）. We first established a CP rat model, then isolated the L5-S2 spinal dorsal horn neurons for further studies. ASICla was knocked down and its effects on the expression of neurogenic inflammation-related factors in the dorsal horn neurons of rat spinal cord were evaluated. The effect of ASICla on the Ca2＋ ion concentration in the dorsal horn neurons of rat spinal cord was measured by the intracellular calcium （[Ca~＊]i） intensity. The effect of ASICla on the p38/mitogen-activated protein kinase （MAPK） signaling pathway was also determined. ASICla was significantly upregulated in the CP rat model as compared with control rats. Acid-induced ASICla expression increased [Ca2＋]i intensity in the dorsal horn neurons of rat spinal cord. ASICla also increased the levels of neurogenic inflammation-related factors and p-p38 expression in the acid-treated dorsal horn neurons. Notably, ASICla knockdown significantly decreased the expression of pro-inflammatory cytokines. Furthermore, the levels of p-p38 and pro-inflammatory cytokines in acid-treated dorsal horn neurons were significantly decreased in the presence of PcTx-1, BAPTA-AM, or SB203580. Our results showed that ASIC1a may contribute to the symptom of pain in patients with CP, at least partially, by regulating the p38/MAPK signaling pathway.

Current efficiency of Ga electrodeposition under different anions concentrations

The gallium electrodeposition from alkaline solution has a very low current efficiency, the reason for which is still not quite understood. The effects of electrode materials used for gallium electrodeposition, as well as the effects of NaOH concentration and the anions concentrations in the solution, including 5042-, SiO32-, CO32-, AlO2-, F-, and CI-, on the deposition were analyzed in this study. The suitable materials of SUS316-SUS316 were suggested for the gallium electrodeposition. Based on the electrode couples, the NaOH concentration of 4 mol.L-1 for gallium electrodeposition exhibits the greatest current efficiency. Moreover, the current efficiency would decrease in the electrolyte along with the increasing concentration of the anions, except that, 0.2 mol-L-1 C1- in the solution slightly improves the current efficiency of gallium elec- trodeposition. Moreover, the gallium deposited on the cathode from the solution with 0.6 mol.L-1 SiO32- appears tiny black in color and coarse. Meanwhile, SUS304 is shown to be not suitable to be used as cathode for the gallium electrodeposition from the alkaline solution.

Enhanced visible-light photoelectrochemical performance via chemical vapor deposition of Fe2O3 on a WO3 film to form a heterojunction

A heterojunction photoanode of Fe2O3 loaded on a WO3 film on a fluorine-doped tin oxide substrate(FTO-WO3/Fe2O3)was prepared via a simple hydrothermal and chemical vapor deposition(CVD)growth method.The photoanode showed higher photoelectrochemical(PEC)water-splitting activity than that of the pristine FTO-WO3 under simulated sunlight because of the synergistic effect of Fe2O3 and WO3.The as-synthesized material was characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and X-ray photoelectron spectroscopy(XPS).The photocurrent density was estimated by linear sweep voltammetry and further confirmed using intensity-modulated photocurrent spectra.Experiments demonstrated that the coated Fe2O3 enhanced the separation and migration efficiencies of the photoinduced electrons and holes,improving the PEC water-splitting properties.The FTO-WO3/Fe2O3 photoanode showed a 1.25 times enhancement in photocurrent density compared with FTO-WO3.This result suggests that facile chemical vapor deposition growth is an effective way to fabricate heterojunctions and improve the properties of WO3 photoanodes for PEC water-splitting applications.

Cooperative Supramolecular Polymerization of Propeller-Shaped Triphenylamine Cyanostilbenes for Explosive Detection

Self-assembly ofπ-conjugated compounds into supramolecular polymers has received considerable attention because of their intrinsic scientific interests and technological applications.As compared toπ-conjugated rods,discotics,and macrocycles,propeller-shapedπ-conjugated molecules have been less exploited to form long-range-ordered supramolecular polymers.Herein a novel type of supramolecular polymers has been constructed on the basis of propeller-shaped triphenylamine cyanostilbenes.The designed compound adopts nucleation-elongation cooperative mechanism for the supramolecular polymerization process,because of the participation of three-fold hydrogen bonds between the neighbouring monomers.The supramolecular polymeric state displays amplified chirality and enhanced emission than those in the monomeric state.The resulting supramolecular polymers exhibit severe emission quenching upon addition of 2,6-dinitrotoluene,ascribed to photoinduced electron transfer from the triphenylamine cyanostilbenes to the explosive analyte.The current study proves the feasibility to supramolecular polymerize propeller-likeπ-conjugated molecules,serving as a promising type of explosive sensor owing to their guest encapsulation and signal amplification capabilities.

Effect of Soda Ash on Properties of Mold Flux and Mineralogical Structures of Flux Film

During continuous casting,properties of mold flux and mineralogical structures of flux film play important roles in controlling steel quality.The effect of soda ash on the physical properties and crystallization characteristics of mold flux was investigated using process mineralogy,including polarizing microscopy,X-ray diffraction,and electron microprobe,etc.Mold flux was mainly prepared using cement clinker and industrial mineral materials under laboratory conditions,and the mineralogical structures of the flux film were systematically identified and quantitatively analyzed.The results showed that,by increasing the soda ash content from 10mass% to 18mass%,the crystallization temperature,critical cooling rate and crystallization ratio of the flux film decreased,but the crystallization ratio still reached 75% after adding soda ash,and the mineral compositions and microstructures of the flux film changed slightly.When the soda ash content exceeded 14mass%,the critical cooling rate and the crystallization ratio decreased slightly,whereas the mineral content of the flux film changed evidently,with a large amount of cuspidine precipitation and a significant decrease in the wollastonite content until it reached zero,which resulted in deterioration of the lubrication of the flux film.

Insight-HXMT on-orbit thermal control status and thermal deformation impact analysis

Purpose The Hard X-ray Modulation Telescope is China’s first X-ray astronomy satellite launched on June 15,2017,dubbed Insight-HXMT.Active and passive thermal control measures are employed to keep devices at suitable temperatures.In this paper,we analyzed the on-orbit thermal monitoring data of the first 5 years and investigated the effect of thermal deformation on the point spread function(PSF)of the telescopes.Methods We examined the data of the on-orbit temperatures measured using 157 thermistors placed on the collimators,detectors and their support structures and compared the results with the thermal control requirements.The thermal deformation was evaluated by the relative orientation of the two star sensors installed on the main support structure.Its effect was estimated with evolution of the PSF obtained with calibration scanning observations of the Crab nebula.Conclusion The on-orbit temperatures met the thermal control requirements thus far,and the effect of thermal deformation on the PSF was negligible after the on-orbit pointing calibration.

Five-year in-orbit background of Insight-HXMT

Purpose We present the five-year in-orbit background evolution of Insight-HXMT since the launch,as well as the effects of the background model in data analysis.Methods The backgrounds of the three main payloads,i.e.,low-energy telescope,medium-energy telescope,and high-energy telescope,are described.The evolution of the background over time is obtained by simply comparing the background in every year during the in-orbit operation of Insight-HXMT.Results The major observational characteristics of the Insight-HXMT in-orbit background are presented,including the light curve,spectrum,geographical distribution,and long-term evolution.The systematic error in background estimation is investigated for every year.Conclusion The observational characteristics of the five-year in-orbit background are consistent with our knowledge of the satellite design and the space environment,and the background model is still valid for the latest observations of Insight-HXMT.

In-orbit performance of HE onboard Insight-HXMT in the first 5 years

Purpose The high-energy X-ray telescope(HE),one of the three main payloads of the Insight-HXMT mission,is composed of eighteen NaI(Tl)/CsI(Na)phoswich detectors,where NaI(Tl)serves as the primary detector covering 20–250 keV,and CsI(Na)is used as an active shield detector to suppress the background of NaI(Tl)and also serves as an all-sky gammaray burst monitor covering 0.2–3MeV.In this paper,we review the in-orbit performance of HE in the first 5 years since Insight-HXMT was launched on June 15,2017.Methods The major performances we concern include the gain and energy resolution of NaI(Tl)and CsI(Na)detectors,the performance of pulse shape discriminator(PSD)and system dead time.In this work,we investigate these performances mainly using the data of blank-sky observations and the data when the telescope is in earth occultation.Results The overall performance of HE/NaI(Tl)is very stable in the first 5 years,whereas the gain of HE/CsI(Na)shows a continuously increasing trend and should be calibrated regularly.Conclusion In general,HE is still in good health and well-calibrated status after five-year’s operation.The in-orbit performance of HE has no significant deviation from expectation.HE is expected to be in operation healthily for another several years of extended mission life.