预拉伸对聚丁二酸丁二醇酯/碳纳米管复合材料结晶行为及力学性能影响

以熔融共混法制备了碳纳米管(CNTs)增强的聚丁二酸丁二醇酯(PBS)复合材料,研究了预拉伸对PBS/CNTs复合材料结晶行为及力学性能的影响。CNTs的加入在复合材料中起到了异相成核作用,促进了PBS的结晶,提高了复合材料的力学性能。单轴预拉伸使CNTs与PBS分子链的有序程度同时增加,有序排列的CNTs进一步增加了PBS晶体的取向度,预拉伸与CNTs对复合材料的增强实现了协同作用。然而,加入CNTs以及在不同温度、不同拉伸应变下的预拉伸均未导致PBS晶体结构发生转变。经在60℃预拉伸500%的PBS/CNTs(质量分数5%)复合材料,其拉伸强度达到286.1 MPa、弹性模量达2.9 GPa,实现了对PBS的增强。

Macadam’s theory in RGB laser display

We have developed Macadam’s theory to deal with RGB laser display, which can well describe the color gamut display system varying with the laser bandwidth. By calculating the volume of R¨osch–Macadam color solid of laser display system under the Rec.2020 standard, we can obtain that the volume of chromatic stereoscopic at 30-nm laser spectral linewidth is about 90% of that at 1 nm laser spectral linewidth, which is important in laser display system to trade off the color gamut and the suppression of laser speckles. Moreover, we can also calculate the color gamut volume with different primary numbers and different primary wavelengths.

Passive, Stable and Order-Adjustable SBS Q-Switching Fiber Laser

We propose a new method to separate different orders of an all-fiber passive Q-switching stimulated Brillouin scattering（SBS） laser. We use two fiber Bragg gratings connected by two circulators for the filtering. We obtain a stabilized pulse laser and measure the pulse width of different orders. The first order of SBS has a central wavelength of 1549.75 nm, an average output power of 9 mW, and a pulse width of 400 ns. The pulse width of SBS is reduced by the higher-order signals with the larger fluctuations.

CAS and CEA in the Treatment of Severe Internal Carotid Artery Stenosis

Objective:To explore the clinical value of carotid artery stent implantation(CAS)and carotid endarterectomy(CEA)in the treatment of patients with severe internal carotid artery stenosis.Methods:88 patients with severe carotid artery stenosis who underwent CAS and CEA in the First People's Hospital of Changde City(hereafter referred as "our hospital")from January 2018 to December 2020 were selected as the research objects and divided into CAS group(n=43)and CEA group(n=45).To understand the clinical application value and feasibility of the two surgical schemes by comparing the general situation,cerebral blood flow,MMSE scale,MOCA scale score and serum miR-145,IGF1R levels of the two surgical schemes.Conclusions:CAS and CEA in the treatment of patients with severe internal carotid artery stenosis,have good curative effect,can effectively improve the patient's cerebral blood flow,regulate serum miR-145,IGF 1R levels,promote the recovery of cognitive function,but relatively speaking,the incidence of stroke and hypotension after CAS is higher,and the incidence of hypertension after CEA is higher.

Application of an atmospheric pressure plasma jet in a rat model of ischaemic stroke:Design,optimisation,and characteristics

Recent studies have shown the in vitro neuro-protective functions of atmospheric pressure plasma(APP)against multiple pathological injuries during ischaemic stroke(IS).However,whether APP treatment exerts a therapeutic effect on a rat IS model remains unclear.Here,on the basis of needle-to-ring dielectric barrier discharge,an atmospheric pressure plasma jet(APPJ)was designed,with the Helium as the working gas which was driven by a sinusoidal voltage.Then,the treatment conditions were optimised for IS rat model treatment and the characteristics of this APPJ were further diagnosed.Subsequently,the rat IS model was established through 90 min middle cerebral artery occlusion(MCAO),and plasma was intermittently inhaled by rats via the nasal cavity for a 2 min period at 60 min of MCAO process.The therapeutic effects of this plasma jet device were then evaluated using biomedical analyses.According to our results,intermittent APP inhalation in the MCAO rats increased the serum NO content,improved the neurological function,enhanced regional cerebral blood flow,lowered brain infarction,and reduced the cell apoptosis in brain tissues of MCAO rats.Collectively,our data provides a novel potential strategy for IS treatment by using atmospheric-pressure plasma inhalation.

一种用于高速气流瞬态测温的快速响应热电偶

为准确测量气体高速流动过程中温度的变化情况,人们对温度传感器的快速响应特性提出了更高的要求.为此,采用直径为30μm的铜丝和康铜丝,利用可控脉冲放电装置焊接制作了T型快速响应热电偶,并测定了热电偶动态响应特性,得到该热电偶时间常数约为40 ms.考虑到热电偶丝对感温结点附近流体状态的影响,以及热电偶的铠装结构对测点附近流场的影响,快速响应热电偶使用新型铠装结构,感温结点裸露,具有更高的可靠性和更好的动态响应特性.

The efficacy assessment of convalescent plasma therapy for COVID-19 patients:a multi-center case series

Convalescent plasma(CP)transfusion has been indicated as a promising therapy in the treatment for other emerging viral infections.However,the quality control of CP and individual variation in patients in different studies make it rather difficult to evaluate the efficacy and risk of CP therapy for coronavirus disease 2019(COVID-19).We aimed to explore the potential efficacy of CP therapy,and to assess the possible factors associated with its efficacy.We enrolled eight critical or severe COVID-19 patients from four centers.Each patient was transfused with 200–400mL of CP from seven recovered donors.The primary indicators for clinical efficacy assessment were the changes of clinical symptoms,laboratory parameters,and radiological image after CP transfusion.CP donors had a wide range of antibody levels measured by serology tests which were to some degree correlated with the neutralizing antibody(NAb)level.No adverse events were observed during and after CP transfusion.Following CP transfusion,six out of eight patients showed improved oxygen support status;chest CT indicated varying degrees of absorption of pulmonary lesions in six patients within 8 days;the viral load was decreased to a negative level in five patients who had the previous viremia;other laboratory parameters also tended to improve,including increased lymphocyte counts,decreased C-reactive protein,procalcitonin,and indicators for liver function.The clinical efficacy might be associated with CP transfusion time,transfused dose,and the NAb levels of CP.This study indicated that CP might be a potential therapy for severe patients with COVID-19.

Self-starting passively mode-locked all fiber laser based on carbon nanotubes with radially polarized emission

We demonstrate an all fiber passively mode-locked laser emitting a radially polarized beam by using a few-mode fiber Bragg grating to achieve mode selection and spectrum filtering. An offset splicing of single-mode fiber with four-mode fiber is utilized as a mode coupler in the laser cavity. Carbon nanotubes are introduced into the laser cavity as the saturable absorber to achieve self-start mode locking. The laser operates at 1547.5 nm with a narrow spectrum width of 0.3 nm at 30 d B. The emitted mode-locked pulses have a duration of 22.73 ps and repetition of10.61 MHz. A radially polarized beam has been obtained with high mode purity by adjusting the polarization in the laser cavity.

Detecting the neutrinos mass hierarchy from cosmological data

The neutrino oscillations imply that at least two neutrinos have non-zero masses[1].However,up to now,we only measure the differences of neutrino mass squares in a standard scenario with three massive eigenstates[2],i.e.

Design and analysis of a range-extended acidity detector based on a Nile red laser with tandem cuvette system

A range-extended acidity detector based on Nile red was designed and analyzed in this work. In light of the good lasing property and solvatochromism characteristic of Nile red/ethanol solution, we have obtained laser spectra of sulfuric acid in different concentrations doped in this substrate. Moreover, to expand the acidity detection range, we proposed a tandem cuvette system containing rhodamine 6G/ethanol and Nile red/ethanol. Consequently, the detection range could be enlarged from 26 nm to 40 nm, by changing not only the wavelength peak but also by the intensity ratio of dual-wavelength laser output. In addition, by changing the detection and substrate materials, the whole detection range could be expanded, and therefore a wide range of applications in polarity and acidity detection could be implemented via this method.

How will our knowledge of short gamma-ray bursts affect the distance measurement of binary neutron stars?

Gravitational waves from binary neutron stars associated with short gamma-ray bursts have drawn considerable attention due to their prospect in cosmology.For such events,the sky locations of sources can be pinpointed with techniques such as identifying the host galaxies.However,the cosmological applications of these events still suffer from the problem of degeneracy between luminosity distance and inclination angle.To address this issue,a technique was proposed in previous study,i.e.,using the collimation property of short gamma-ray bursts.Based on the observations,we assume that the cosine of inclination follows a Gaussian distribution,which may act as a prior in the Bayes analysis to break the degeneracy.This paper investigates the effects of different Gaussian priors and detector configurations on distance measurement and cosmological research.We first derive a simplified Fisher information matrix for demonstration,and then conduct quantitative analyses via simulation.By varying the number of third-generation detectors and the scale of prior,we generate four catalogs of 1000 events.It is shown that,in the same detecting period,a network of detectors can recognize more and farther events than a single detector.Besides,adopting tighter prior and employing multiple detectors both decrease the error of luminosity distance.Also considered is the performance of a widely adopted formula in the error budget,which turns out to be a conservative choice in each case.As for cosmological applications,for theΛCDM model,500,200,600,and 300 events are required for the four configurations to achieve 1%H;accuracy.With all 1000 events in each catalog,H;and?;can be constrained to(0.66%,0.37%,0.76%,0.49%),and(0.010,0.006,0.013,0.010),respectively.The results of the Gaussian process also show that the gravitational wave standard siren can serve as a probe of cosmology at high redshifts.

Epidemiological and Clinical Characteristics of COVID-19 in Adolescents and Young Adults

BACKGROUND Adolescents and young adults might play a key role in the worldwide spread of Coronavirus Disease 2019(COVID-19)because they are more likely to be involved in overseas study,business,work,and travel.However,the epidemiological and clinical characteristics remain unknown.