3D MERGE与3D SPACE STIR序列在腰椎间盘突出症检查中的应用比较

目的:对比三维多回波恢复梯度回波(3D MERGE)、三维可变反转角快速自旋回波(3D SPACE STIR)序列在腰椎间盘突出症(LDH)检查中的应用效果。方法:选择2020年1月~2022年11月收治的135例LDH患者,回顾性分析患者临床和磁共振成像(MRI)资料,所有患者均接受常规MRI扫描及3D MERGE、3D SPACE STIR序列扫描,对比3D MERGE、3D SPACE STIR序列测量神经根直径的一致性,评价两种序列的图像质量参数[信噪比(SNR)、对比噪声比(CNR)]、图像清晰度评分。结果:3D MERGE和3D SPACE STIR序列测量的L3~S1神经根直径比较差异无统计学意义(P>0.05),且两组序列测量的L3、L4、L5和S1直径均显示出较高相关性(r=0.957,0.986,0.975,0.972,P<0.05);3D MERGE序列的SNR及CNR均高于3D SPACE STIR序列,神经根显示分级、图像清晰度评分优于3D SPACE STIR序列,差异有统计学意义(P<0.05)。结论:3D MERGE、3D SPACE STIR序列在LDH神经根直径测量中具有极高一致性,3D MERGE序列较3D SPACE STIR序列能够更清晰显示神经跟的解剖形态,图像质量更好。

Synthesis of Nanosized NaY Zeolite by Confined Space Method

Nanosized NaY crystals have been prepared from metakaolin and sodium silicate by confined space synthesis with starch additive. It is found that the product has a narrow crystal size distribution (50-100 nm), high Si/Al ratio (Si/Al=4.6-6.1), high surface area (1090 m2/g) and the average diameter of nanosized NaY (75 nm) synthesized is 30 nm, it is smaller than that of without starch additive.

Analysis of temporal and spatial distribution characteristics of ammonium chloride smoke particles in confined spaces

In response to the demand for short-range detection of anti-smoke environment interference by laser fuzes,this study proposes a smoke environment simulation of non-uniform continuous point source diffusion and investigates an experimental laboratory smoke environment using an ammonium chloride smoke agent.The particle size distribution,composition,and mass flow distribution of the smoke were studied.Based on a discrete phase model and a kεturbulence model,a numerical simulation was developed to model the smoke generation and diffusion processes of the smoke agent in a confined space.The temporal and spatial distribution characteristics of the smoke mass concentration,velocity,and temperature in the space after smoke generation were analyzed,and the motion law governing the smoke diffusion throughout the entire space was summarized.Combined with the experimental verification of the smoke environment laboratory,the results showed that the smoke plume changed from fan-shaped to umbrella-shaped during smoke generation,and then continued to spread around.Meanwhile,the mass concentration of smoke in the space decreased from the middle outward;the changes in temperature and velocity were small and stable.In the diffusion stage(after 900 s),the mass concentration of smoke above 0.8 m was relatively uniform across an area of smoke that was 12 m thick.The concentration decreased over time,following a consistent decreasing trend,and the attenuation was negligible in a very short time.Therefore,this system was suitable for conducting experimental research on laser fuzes in a smoke environment.Owing to the stability of the equipment and facilities,the setup could reproduce the same experimental smoke environment by artificially controlling the smoke emission of the smoke agent.Overall,this work provides a theoretical reference for subsequent research efforts regarding the construction of uniform smoke environments and evaluating laser transmission characteristics in smoky environments.

我国研究生学术素养研究热点分析(2013—2023年)——基于Cite Space的可视化分析研究

从中国知网数据库检索2013—2023年底国内发表的研究生学术素养研究相关文献,共筛选出259篇相关文献。将文献纳入Cite Space中,分别对作者、机构、关键词等进行可视化分析,并通过Excel绘制年发文量折线图,发现年发文量总体呈现下降趋势。发文作者为教育学领域的居多,发文机构大部分来自于各学校研究所等。高频关键词有研究生、学术道德、学术不端、学术规范、学术素养,并形成了“研究生”“学术道德”“学术不端”“治理”“学术规范”“学术素养”“博士生”“道德理论”“中心和导向”9个聚类。研究者近年来对学术素养相关研究整体呈现下降状态;研究机构以及研究人员结构单一,国家机构对学术素养相关研究较少;但关于“研究生”“学术道德”“学术不端”以及“学术理论”的研究仍有较高热度。

国内“大思政课”研究的现状、热点与展望--基于CiteSpace的核心期刊论文可视化分析

“大思政课”是近年的一个新议题。自习近平总书记作出关于“大思政课”的重要论述以来,“大思政课”建设在全国积极推进,成为新时代用党的创新理论铸魂育人的重要抓手。学界对这一领域的研究成果持续涌现。借助Cite Space文献计量软件对中国知网CNKI数据库中2021-2023年间350篇核心期刊论文的发文量、作者、机构、关键词进行可视化分析,近三年学界的研究热点聚焦“大思政课”的本体论、认识论、价值论、方法论以及一体化等方面。未来,学界还应以多学科交叉和多主体融合实现“大思政课”研究的系统化,以理论和实践结合提升“大思政课”研究的科学化,以破解技术遮蔽与AI赋能强化“大思政课”研究的数字化,以研究反哺教学,不断增强“大思政课”立德树人实效。

Numerical simulation of detonation of an explosive atmosphere of liquefied petroleum gas in a confined space

The detonation of an explosive atmosphere from liquefied petroleum gas disseminated in air in a confined space is studied using numerical modeling with software product ANSYS AUTODYN.

Modeling and analysis of a catastrophic oil spill and vapor cloud explosion in a confined space upon oil pipeline leaking

Oil spill-induced vapor cloud explosions in a confined space can cause catastrophic consequences.In this work,investigation was conducted on the catastrophic pipeline leak,oil spill,and the resulting vapor cloud explosion accident occurring in China in 2013 by modeling analysis,field surveys,and numerical simulations.The total amount of the spilled oil was up to2044.4 m3 due to improper disposal.The long residence time of the oil remaining in a confined space permitted the formation of explosive mixtures and caused the vapor cloud explosion.A numerical model was developed to estimate the consequence of the explosion based on volatilization testing results.The results show that the death-leading zone and the glass-breaking zone could be 18 m and 92 m,respectively,which are consistent with the field investigation.The severity of the explosion is related to the amount of the oil spill,properties of oil,and volatilization time.It is recommended that a comprehensive risk assessment be conducted to analyze the possible consequences upon oil spilling into a confined space.Prompt collection and ventilation measures should be taken immediately after the spill occurs to reduce the time for oil volatilization and prevent the mixture from reaching its explosive limit.

基于Cite Space对螺旋藻藻蓝蛋白的研究进展与热点分析

螺旋藻(Spirulina)藻蓝蛋白具有独特的理化特性及生理功能,是药物、食品和化妆品的天然原料,具有较大的开发潜力。为探讨螺旋藻藻蓝蛋白的研究现状与发展前景,对中国知网和Web of Science数据库中1990—2023年发表的文献进行检索并筛选,使用Cite Space软件对文章发文量、研究团队及研究热点进行图谱分析。综合分析可知,国内年发文量偏少,呈平稳趋势;国外年发文量持续上升,尤其近几年发文量迅速增长,且发文量超过了100篇;国外研究热点集中于藻蓝蛋白在食品、医药行业的应用方面,而国内研究热点集中在提取纯化、稳定性、功能活性的研究与应用,下一步应结合研究现状开发适合规模化生产的提取纯化工艺,进一步加强藻蓝蛋白研究的广度与深度;国内外研究群体主要是高校的相关生物技术学院或研究机构等,总体来讲,学者间存在较为密切的合作,但研究机构间尚未形成紧密的合作关系,在地域上比较分散,各大高校和研究机构应突破地区或机构间的各种限制,促进该研究领域的深度融合和快速发展,深入挖掘藻蓝蛋白在各个领域的潜在应用。

Fabrication of Cu^(+) sites in confined spaces for adsorptive desulfurization by series connection double-solvent strategy

Cu^(+)-containing materials have shown various application prospects especially in adsorption and catalysis,because they are versatile,nontoxic and low cost.To date,developing a mild and controllable approach for the fabrication of Cu^(+) sites has remained a pronounced challenge.Herein,we report a series connection double-solvent strategy(SCDS) for fabricating Cu^(+)sites within MIL-101(Cr),a typical metal–organic framework.By employing the SCDS in which vitamin C is chosen as the environmentally benign reducing agent,Cu^(2+) was incorporated in the pores and then transformed to Cu^(+) in the confined spaces.Compared to the conventional high-temperature autoreduction method conducted under harsh environment(700°C for 12 h) with a low Cu^(+) yield(less than 50%),SCDS can selectively reduce Cu^(2+)to Cu^(+) at room temperature without generating any CuO.The resulting Cu^(+)modified MIL-101(Cr) exhibits good desulfurization performance in view of both uptake and recyclability.

基于CiteSpace的红色文创设计可视化分析与方法研究

目的基于CiteSpace概述国内红色文创设计的发展状况,梳理关于红色文创设计的相关方法与理论模型,探讨未来红色文创设计发展的趋势,为研究者提供相关设计思路与发展动向。方法通过对国内相关文献的研究,梳理了红色文创设计的概念与发展现状,归纳了当前红色文创设计中包括文化转译维度、文化层次理论、叙事性设计的三种主要方法与理论模型。结论目前红色文创设计方法较为单一,很难满足用户的不同需求,且缺乏具体针对性的完整理论体系与设计方法。在今后的红色文创设计中,可以综合运用叙事性及文化转译维度等设计理论和手段,对红色文创设计和方法加以探究和创新,打造具有中国特色的红色文创产品,使红色文化得到更好的普及和弘扬。

Mitigation effects on the reflected overpressure of blast shock with water surrounding an explosive in a confined space

The mitigation of blast shock with water has broad application prospects. Understanding the mitigation effects on the reflected overpressure of the explosion shock with water surrounding an explosive in a confined space is of great significance for military explosives safety applications. To estimate the effects of the parameters on the reflected overpressure of blasted shock wave, a series of experiments were carried out in confined containers with spherical explosives immersed in a certain thickness of water,and numerical simulations were conducted to explore the corresponding mechanisms. The results reveal that the reflected overpressure is abnormally aggravated at a small scaled distance. This aggravation is due to the high impulse of the bulk accelerated water shell converted from the explosion. With increasing scaled distance, the energy will be gradually dissipated. The mitigation effects will appear with the dispersed water phase front impacting at a larger scaled distance, except in the case of a dense water phase state. A critical scaled distance range of 0.7-0.8 m/kg^(1/3) for effective mitigation was found. It is suggested that the scaled distance of space walls should be larger than the critical value for a certain water-to-explosive weight ratio range(5-20).

Tandem Lewis acid catalysis for the conversion of alkenes to 1,2‐diols in the confined space of bifunctional TiSn‐Beta zeolite

The generation of multifunctional isolated active sites in zeolite supports is an attractive method for integrating multistep sequential reactions into a single‐pass tandem catalytic reaction.In this study,bifunctional TiSn‐Beta zeolite was prepared by a simple and scalable post‐synthesis approach,and it was utilized as an efficient heterogeneous catalyst for the tandem conversion of alkenes to 1,2‐diols.The isolated Ti and Sn Lewis acid sites within the TiSn‐Beta zeolite can efficiently integrate alkene epoxidation and epoxide hydration in tandem in a zeolite microreactor to achieve one‐step conversion of alkenes to 1,2‐diols with a high selectivity of>90%.Zeolite confinement effects result in high tandem rates of alkene epoxidation and epoxide hydration as well as high selectivity toward the desired product.Further,the novel method demonstrated herein can be employed to other tandem catalytic reactions for sustainable chemical production.

Compressed wormlike chain moving out of confined space: A model of DNA ejection from bacteriophage

The molecular biomechanics of DNA ejection from bacteriophage is of interest to not only fundamental biological understandings but also practical applications such as the design of advanced site-specific and controllable drug delivery systems. In this paper, we analyze the viscous motion of a semiflexible polymer chain coming out of a strongly confined space as a model to investigate the effects of various structure confinements and frictional resistances encountered during the DNA ejection process. The theoretically predicted relations between the ejection speed, ejection time, ejection length, and other physical parameters, such as the phage type, total genome length and ionic state of external buffer solutions, show excellent agreement with in vitro experimental observations in the literature.

基于Cite Space可视化分析我国多发伤急救研究热点及趋势

目的梳理国内多发伤急救相关研究文献,分析研究现状、热点和趋势,为我国多发伤急救研究提供借鉴和指导。方法检索中国知网数据库中2011—2021年关于多发伤急救的相关文献,使用Cite Space 6.1.R3可视化软件对该领域的年发文量、机构、作者、关键词进行分析。结果最终纳入多发伤急救研究文献2519篇,整体发文数量较平稳,以2016年为小高峰;发文量最高的机构是华中科技大学附属同济医院。多发伤急救研究热点包括院前急救、并发症护理、风险因素分析和预后效果评估,研究前沿包括不同多发伤人群的诊断、治疗、手术和护理体会等方面。结论本文通过可视化分析国内多发伤急救研究的热点及趋势,指明了多发伤目前研究存在的问题和未来研究发展的方向,为进一步完善多发伤急救卫生服务和管理体系提供指导。

Separation of Oil Phase from Dilute Oil/Water Emulsion in Confined Space Apparatus

A miniature process for separating the oil phase from dilute oil/water emulsion is developed.This process applies a confined space apparatus,which is a thin flow channel made of two parallel plastic plates.The space between the two plates is rather narrow to improve the collisions between oil droplets and the plate surface.Oil droplets have an affinity for the plate surface and thus are captured,and then coalesce onto the surface.The droplet size distribution of the residual emulsion resulted from the separation process is remarkably changed.The oil layer on the plate weakens the further separation of oil droplets from the emulsion.Three types of plate materials,polypropylene(PP),polytetrafluoroethylene(PTFE) and nylon 66,were used.It is found that PP is the best in terms of the oil separation efficiency and nylon 66 is the poorest.The interaction between droplets in the emulsion and plate surface is indicated by the spreading coefficient of oil droplet on the plate in aqueous environment,and the influences of formed oil layer and plate material on the separation efficiency are discussed.

基于CiteSpace知识图谱的智慧养老领域研究文献综述

“十四五”规划将发展智慧养老产业上升为国家战略高度。文章借助Cite Space和Vosviewer绘图软件对2012-2022年国内外智慧养老领域研究的发文量、突现词等进行可视化分析。发现国内外研究都经历了三个发展阶段,国外研究起步早,研究成果丰富;国内研究虽然起步较晚,但进展快速。总结出“智慧养老内涵”“智慧养老模式”“智慧养老产业”“智慧养老平台”“智慧养老产品”“智慧养老用户”六大国内外都重点关注的研究议题,发现技术赋能智慧养老发展是近年来国内外共同关注的研究热点,大数据、物联网、养老金融、数字技术、区块链等成为围绕智慧养老文献的关键词。

Accidents during Tanker Accident in Confined Spaces

One of the major hazards when working onboard Tankers is working in confined spaces, improving the procedures in working in such spaces is obvious, but developing the equipments used in rescue operation is rare to happen, that＇s why this paper is focusing on differentiating between the manual ＆ more developed equipments used specially in rescuing the crew in such an adequate time, to save the workers＇ life. The manual way is called ＂MUCKY CRANE＂ which is used for rescue purposes onboard tankers, in any of the confined spaces, should be replaced by excel crane which is air or hydraulic driven machine, to achieve better results. As safety precautions measures taken in such tasks are not enough for the required objective achievement. Such safety procedures have been discussed and critical situations have been pointed out.

Blast performance of layered charges enveloped by aluminum powder/rubber composites in confined spaces

A layered charge composed of the JH-2 explosive enveloped by a thick-walled cylindrical casing(active aluminum/rubber and inert lithium fluoride/rubber composites) was designed and explosion experiments were conducted in a 1.3 m3tank and a 113 m3bunker.The blast parameters,including the quasistatic pressure(ΔpQS),special impulse(I),and peak overpressure(Δpmax),and images of the explosion process were recorded,and the influence of the Al content(30% and 50%) and Al particle size(1,10,and 50 μm) on the energy release of aluminum/rubber composites were investigated.The results revealed that the use of an active layer increased the peak overpressure generated by the primary blast wave,as well as the quasistatic pressure and special impulse related to fuel burning within tens of milliseconds after detonation.When the Al content was increased from 30% to 50%,the increases of ΔpQS and I were not obvious,and Δpmaxeven decreased,possibly because of decreased combustion efficiency and greater absorption of the blast wave energy for layers with 50% Al.Compared with the pure JH-2charge,the charge with 1 μm Al particles produced the highest Δpmax,indicating that better transient blast performance was generated by smaller Al particles.However,the charge with 10 μm Al particles showed the largest ΔpQSand I,suggesting that a stronger destructive effect occurred over a longer duration for charges that contained moderate 10 μm Al.

中国人才政策研究的现状与趋势——基于Cite Space的可视化分析

科学的人才政策是实现人才强国和科教兴国战略的重要保障。借助Cite Space量化分析软件,分别从发文作者、发文机构、高被引文献、关键词等方面对人才政策研究情况进行可视化分析,在整合既有研究基础上展望未来。研究表明:我国人才政策研究主要聚焦于人才政策本身、实施存在的问题、可行性路径三个维度。当前的研究热点主题为人才战略、人才开发、人才培养,已有关键词之间关联性不强,机构合作密度不高,缺少系统研究框架和强大理论支持。据此,今后人才政策的研究应该加强跨学科融合思考,建构具有中国特色的本土化研究架构,注重人才培养的硬环境和软环境建设。

基于CiteSpace对近10年国内外护理不良事件的可视化分析

为了解国内外近10年护理不良事件的研究热点与前沿,为医院管理和临床护士提供参考,保障患者安全,通过检索中国期刊全文数据库(CNKI)和Web of Science(WOS)数据库,检索时限为2012年1月—2022年8月,导入CiteSpace进行可视化分析。研究显示,从发文量看,国内外学者对护理不良事件的关注度整体较高,可视化分析结果并未发现作者之间、机构之间的联系。未来减少护理不良事件的方法一定会越来越紧贴科学技术,越来越多的新型信息化平台、App等会用于医疗行业,降低护理不良事件预防的难度,但护理人员仍要重视护理安全。