Thermal comfort in a building with Trombe wall integrated with phase change materials in hot summer and cold winter region without air conditioning

Trombe wall and phase change materials(PCMs)are two effective ways to regulate indoor thermal comfort.However,Trombe wall surfers from overheating in summer and PCMs suffer from low heat transfer rate caused by the limited thermal conductivity.To compensate the shortcomings of the two methods,this paper proposed a Trombe wall system integrated with PCMs.Based on a light-weight building envelope in Changsha,China,the thermal comfort of 10 kinds of Trombe wall systems with PCMs with a melting temperature of 18-28℃ were studied.Taking the integrated indoor discomfort duration(I_(D)),integrated indoor discomfort degree-hour(I_(DH)),indoor air temperature(T_(in)),PCM liquid fraction(γ)and heat flux across wall(q)as evaluation indexes,the indoor thermal comfort was assessed in hot summer and cold winter region.Results show that the Trombe wall helped PCMs complete the phase change process effectively.Trombe wall with PCM25 next to the wall inner surface possessed the lowest annual I_(D) and I_(DH),as 2877 h and 12,974℃·h,respectively.Compared with the values in a traditional building,the I_(D) and I_(DH) were reduced by 7.01% and 14.14%.In order to give full play to the heat storage and heat release of the Trombe wall with PCMs,PCMs with phase change temperature 7℃ lower than the peak ambient temperature in summer or 8℃ higher than the winter night temperature was recommended according to regional climate conditions.

Free cash flow productivity among Chinese listed companies:A comparative study of SOEs and non-SOEs

This paper investigates the free cash flow productivity of SOEs compared with non-SOEs and examines its possible determinants.We find that SOEs have slightly weak free cash flow productivity but significantly stronger than non-SOEs.Similar performance exists among commercial class I and II SOEs and public-benefit SOEs.Further analyses suggest that firm size,age,sales growth,ownership concentration,government subsidies,and industry monopoly factors cannot explain this phenomenon.The common driver for all types of SOEs to generate stronger free cash flows than non-SOEs is their stronger expense control capability.

^(18)F-FDG PET/CT在新型冠状病毒肺炎诊断中的应用

新型冠状病毒肺炎(COVID-19)被发现以来,迅速蔓延,其早期诊断有利于患者的及时救治和疾病进一步传播的有效控制。目前,诊断的依据是流行病史、临床表现、影像学特征和逆转录聚合酶链式反应(RT-PCR)检测结果,其中RT-PCR检测到新型冠状病毒核酸阳性是COVID-19确诊的主要依据,影像学特征尤其是肺部高分辨率CT表现则是诊断该病的重要临床依据。作为一种被广泛应用的影像学方法,^(18)F-FDG PET/CT在COVID-19中的价值仍未可知。笔者分析了^(18)F-FDG PET/CT在COVID-19中的诊断和鉴别诊断的价值,以及评估COVID-19患者纵隔淋巴结受累情况方面的潜在应用,讨论了COVID-19患者肺外器官和组织受累可能出现的^(18)F-FDG PET/CT影像学表现。

An artificial neural network chip based on two-dimensional semiconductor

Recently,research on two-dimensional(2D)semiconductors has begun to translate from the fundamen-tal investigation into rudimentary functional circuits.In this work,we unveil the first functional MoS2 artificial neural network(ANN)chip,including multiply-and-accumulate(MAC),memory and activation function circuits.Such MoS2 ANN chip is realized through fabricating 818 field-effect transistors(FETs)on a wafer-scale and high-homogeneity MoS2 film,with a gate-last process to realize top gate structured FETs.A 62-level simulation program with integrated circuit emphasis(SPICE)model is utilized to design and optimize our analog ANN circuits.To demonstrate a practical application,a tactile digit sensing recognition was demonstrated based on our ANN circuits.After training,the digit recognition rate exceeds 97%.Our work not only demonstrates the protentional of 2D semiconductors in wafer-scale inte-grated circuits,but also paves the way for its future application in AI computation.

The earlier,the better?A review of neoadjuvant immunotherapy in resectable non-small-cell lung cancer

Immune checkpoint inhibitors(ICIs)have revolutionized the approach to advanced and locally advanced non-small-cell lung cancer(NSCLC).Antibodies blocking inhibitory immune checkpoints,such as programmed death 1(PD-1)and its ligand(PD-L1),have remarkable antitumor efficacy and have been approved as a standard first-or second-line treatment in non-oncogene-addicted advanced NSCLC.The successful application of immunotherapy in advanced lung cancer has motivated researchers to further evaluate its clinical role as a neoadjuvant setting for resectable NSCLC and for improved long-term overall survival and curative rates.In this review,we discuss the efforts that incorporate ICIs into the treatment paradigm for surgically resectable lung cancer.We reviewed the early-phase results from neoadjuvant clinical trials,the landscape of the majority of ongoing phase III trials,and discuss the prospects of ICIs as a curative therapy for resectable lung cancer.We also summarized the potential biomarkers and beneficiaries involved in the current study,as well as the remaining unresolved challenges for neoadjuvant immunotherapy.

New form of geodetic coordinate system taking two length quantity as coordinate parameters

A new form of geodetic coordinate system based on geodesic coordinates instead of geodetic longitude and latitude was proposed.The vertical and horizontal geodesic coordinates measured with length were defined as coordinate parameters,but the two families of coordinate curves were still meridians and parallel circles.The first fundamental form on the ellipsoidal surface and its three coefficients were deduced by the geodesic coordinate.The formula for the latitudinal scale factor of length for geodetic parallel lines was derived,by which the obtained result conformed to that standard value calculated from geodetic latitude,and it is applicable in the range of 400 km from north to south.Therefore,it lays the foundation for establishing the differential equation and differential relationship based on this type of coordinate parameters;and consequently,it is convenient and accurate enough to operate on the ellipsoidal surface in this new form of geodetic coordinate system.

Thermal performance of a lightweight building with phase change material under a humid subtropical climate

The use of phase change materials(PCMs)in building enclosures is an efficient way to reduce the heat gain and/or loss in summer and winter.It was evident that the thermal performance of buildings with PCMs was affected by the outdoor air temperature significantly.However,the influence of humidity,which was serious in the humid subtropical climate was unclear.To explore the effect of PCMs under a humid subtropical climate,the thermal performance of a lightweight building outfitted with PCMs with a melting temperature of 25°C was investigated.The actual outdoor air temperature with a humidity of 40-90 RH%and wind velocity of 2-6 m/s blowing from the east,west,south,and north was assumed for the performance assessment.A simulated model was developed using EnergyPlus and verified against experimental data.The energy savings by using PCMs was reduced from 3.9%to 2.6%when the outdoor humidity increased from 40 to 90 RH%in summer.However,the savings was not obvious in winter.Annual energy savings decreased from 1.64%to 1.32%with humidity increasing from 40 to 90 RH%.For annual condition,the average energy savings was reduced from 1.43%to 0.92%when the wind speed increased from 2 m/s to 6 m/s.From an economic point of view,the investment payback period was less than 10 years when the PCM price was lower than 18.0 Yuan/kg.

Non-Ischemic, Non-Hypoxic Myocardial Injury, and Long-Term Mortality in Patients with Coronavirus Disease 2019: A Retrospective Cohort Study

Objective:Cardiac damage is commonly reported in patients with coronavirus disease 2019(COVID-19)but its prevalence and impact on the long-term survival of patients remain uncertain.This study aimed to explore the prevalence of myocardial injury and assess its prognostic value in patients with COVID-19.Methods:A single-center,retrospective cohort study was performed at the Affiliated Hospital of Jianghan University.Data from 766 patients with confirmed COVID-19 who were hospitalized from December 27,2019 to April 25,2020 were collected.Demographic,clinical,laboratory,electrocardiogram,treatment data and all-cause mortality during follow-up were collected and analyzed.Results:Of the 766 patients with moderate to critically ill COVID-19,86(11.2%)died after a mean follow-up of 72.8 days.Myocardial injury occurred in 94(12.3%)patients.The mortality rate was 64.9%(61/94)and 3.7%(25/672)in patients with and without myocardial injury,respectively.Cox regression showed that myocardial injury was an independent risk factor for mortality(hazard ratio:8.76,95%confidence interval:4.76–16.11,P<0.001).Of the 90 patients with myocardial injury with electrocardiogram results,sinus tachycardia was present in 29,bundle branch block in 26,low voltage in 10,and abnormal T-wave in 53.Conclusions:COVID-19 not only involves pneumonia but also cardiac damage.Myocardial injury is a common complication and an independent risk factor for mortality in COVID-19 patients.