森林康养步道设计理论探讨

森林康养步道是森林康养空间体系的重要组成部分,对于开展森林康养活动具有不可或缺的作用。本文结合了与森林康养步道设计相关的森林环境保健因子、环境心理学、运动医学和道路生态学等理论,阐述了森林康养步道的概念、功能及构成要素,希望为森林康养步道的空间布局提供理论依据。最后对森林康养步道设计需要进一步研究的问题进行了探讨。

Extracorporeal Membrane Oxygenation Therapy for Critically Ill Coronavirus Disease 2019 Patients in Wuhan,China:A Retrospective Multicenter Cohort Study

Currently,little in-depth evidence is known about the application of extracorporeal membrane oxygenation(ECMO)therapy in coronavirus disease 2019(COVID-19)patients.This retrospective multicenter cohort study included patients with COVID-19 at 7 designated hospitals in Wuhan,China.The patients were followed up until June 30,2020.Univariate and multivariate logistic regression analyses were performed to identify the risk factors associated with unsuccessful ECMO weaning.Propensity score matching was used to match patients who received veno-venous ECMO with those who received invasive mechanical ventilation(IMV)-only therapy.Of 88 patients receiving ECMO therapy,27 and 61 patients were and were not successfully weaned from ECMO,respectively.Additionally,15,15,and 65 patients were further weaned from IMV,discharged from hospital,or died during hospitalization,respectively.In the multivariate logistic regression analysis,a lymphocyte count≤0.5×10^(9)/L and D-dimer concentration>4×the upper limit of normal level at ICU admission,a peak PaCO_(2)>60 mmHg at 24 h before ECMO initiation,and no tracheotomy performed during the ICU stay were independently associated with lower odds of ECMO weaning.In the propensity scorematched analysis,a mixed-effect Cox model detected a lower hazard ratio for 120-day all-cause mortality after ICU admission during hospitalization in the ECMO group.The presence of lymphocytopenia,higher D-dimer concentrations at ICU admission and hypercapnia before ECMO initiation could help to identify patients with a poor prognosis.Tracheotomy could facilitate weaning from ECMO.ECMO relative to IMV-only therapy was associated with improved outcomes in critically ill COVID-19 patients.

Experimental and Numerical Study on the Gas Explosion in Urban Regulator Station

Regulator station is an important part in the urban gas transmission and distribution system.Once gas explosion occurs,the real explosion process and consequences of methane gas explosion in the regulator station were not revealed systematically.In this study,a full-scale experiment was carried out to simulate the regulator station explosion process,and some numerical simulations with a commercial CFD software called FLACS were conducted to analyze the effect of ignition and vent conditions on the blast overpressure and flame propagation.The experimental results demonstrated that the peak overpressure increased as the distance from the vent increased within a certain distance.And the maximum overpressure appeared 3 m away from the door,which was about 36.6 kPa.It was found that the pressure-time rising curves obtained from the simulation are basically the same as the ones from the experiment,however,the time of reaching the peak pressure was much shorter.The numerical simulation results show that the peak overpressures show an increase trend as the ignition height decreased and the vent relief pressure increased.It indicates that the damage and peak overpressure of gas explosion could be well predicted by FLACS in different styles of regulator station.In addition,the results help us to understand the internal mechanism and development process of gas explosion better.It also offers technical support for the safety protection of the urban regulator station.

老挝民众对“一带一路”倡议的态度及对策建议——基于对老挝进行的实证调研分析

从通过调查问卷、实地访谈等方式了解老挝民众对共建"一带一路"倡议的认知与态度情况来看,老挝民众整体对中国认知度和认可度高,普遍对中国国际影响力持积极评价态度,支持中老共建"一带一路"。但调查也显示,少数民众表达出拆迁补偿不合理、就业机会不均衡、生态环境被破坏等不满情绪。建议中老两国在共建"一带一路"的过程中,加强宣传沟通,构建"双轨"对话机制,促进中老民心相通;两国政府应在全面把握民意的基础上,加强基础设施领域的合作,保障项目沿线民众切身利益,使更多老挝民众共享发展成果。

Convergence mechanism of mindfulness intervention in treating attention deficit hyperactivity disorder:Clues from current evidence

This paper reviews the underlying evidence for various aspects of the convergence mechanism of mindfulness intervention in attention deficit hyperactivity disorder(ADHD).There may be compatibility among various ADHD remission models and the therapeutic mechanism of mindfulness intervention in ADHD may be mainly via the convergence mechanism.However,neuroimaging-based analysis of the mechanisms of mindfulness intervention in treating ADHD is lacking.Differences in the efficacy of various subtypes of mindfulness intervention,and corresponding specific imaging changes need further investigation.Future research may focus on the neuroimaging features of specific mindfulness intervention subtypes.

Secret Data-Driven Carrier-Free Secret Sharing Scheme Based on Error Correction Blocks of QR Codes

In this paper,a novel secret data-driven carrier-free(semi structural formula)visual secret sharing(VSS)scheme with(2,2)threshold based on the error correction blocks of QR codes is investigated.The proposed scheme is to search two QR codes that altered to satisfy the secret sharing modules in the error correction mechanism from the large datasets of QR codes according to the secret image,which is to embed the secret image into QR codes based on carrier-free secret sharing.The size of secret image is the same or closest with the region from the coordinate of(7,7)to the lower right corner of QR codes.In this way,we can find the QR codes combination of embedding secret information maximization with secret data-driven based on Big data search.Each output share is a valid QR code which can be decoded correctly utilizing a QR code reader and it may reduce the likelihood of attracting the attention of potential attackers.The proposed scheme can reveal secret image visually with the abilities of stacking and XOR decryptions.The secret image can be recovered by human visual system(HVS)without any computation based on stacking.On the other hand,if the light-weight computation device is available,the secret image can be lossless revealed based on XOR operation.In addition,QR codes could assist alignment for VSS recovery.The experimental results show the effectiveness of our scheme.

Security Analysis of Secret Image Sharing

Differently from pure data encryption,secret image sharing(SIS)mainly focuses on image protection through generating a secret image into n shadow images(shares)distributed to n associated participants.The secret image can be reconstructed by collecting sufficient shadow images.In recent years,many SIS schemes are proposed,among which Shamir’s polynomial-based SIS scheme and visual secret sharing(VSS)also called visual cryptography scheme(VCS)are the primary branches.However,as the basic research issues,the security analysis and security level classification of SIS are rarely discussed.In this paper,based on the study of image feature and typical SIS schemes,four security levels are classified as well as the security of typical SIS schemes are analyzed.Furthermore,experiments are conducted to evaluate the efficiency of our analysis by employing illustrations and evaluation metrics.

Clarity Corresponding to Contrast in Visual Cryptography

The visual quality of the recovered secret image is usually evaluated by contrast in visual cryptography (VC). Precisely, the reconstructed secret image can be recognized as the original secret image when contrast is greater than zero. It is important for the user to know the clarity of the revealed secret image corresponding to different contrast values. In this paper, the clarity corresponding to contrast is investigated through conducting subjective evaluation scores and objective evaluation indexes, which can be extended to general applications.

乡村振兴背景下农村公共文化服务体系建设的困境与优化路径

文化振兴是乡村振兴的灵魂所在,加快推进农村公共文化体系建设是实现乡村文化振兴、激发乡村全面振兴内生动力的重要着力点。农村公共文化服务在促进乡风文明建设、带动乡村经济发展、实现乡村生态宜居等方面发挥着重要作用。然而,目前农村公共文化体系建设存在诸多问题,制约了农村公共文化服务效能的发挥。因此,需要从思想观念、机制体制、财政资金、人才队伍、硬件设施等方面着手,优化农村公共文化服务体系,高效发挥文化在推动乡村振兴中的应有功能。

Reversible light-driven magnetic switching of salen cobalt complex

Spin-crossover(SCO)metal complexes are expected to be widely used in data storage materials,display devices and sensors.Although a lot of spin-crossover photoswitches have been developed,the reversible photomodulation cases that work at room temperature are limited.Herein,a novel cobalt complex o-1-Co(II)wherein the salen unit bridges with bis-diarylethene has been designed as switch to construct"off-on"logic operation at room temperature.The complex o-1-Co(II)displays an abrupt,reversible and hysteretic spin crossover(T1/2↓=166 K,T1/2↑=177 K,andΔT1/2=11 K)between the high-spin(HS)and low-spin(LS)states.Meanwhile,photocyclization of o-1-Co(II)with UV light produces a photoresponsive closed form c-1-Co(II),which always stays at low-spin without SCO at all.Moreover,the magnetic switching of the complex can also be achieved with redox reactions between Co(II)and Co(III).