Failure behavior around a circular opening in a rock mass with non-persistent joints:A parallel-bond stress corrosion approach

The stability of underground excavations is influenced by discontinuities interspaced in surrounding rock masses as well as the stress condition. In this work, a numerical study was undertaken on the failure behavior around a circular opening in a rock mass having non-persistent open joints using PFC software package. A parallel-bond stress corrosion(PSC) approach was incorporated to drive the failure of rock mass around the circular opening, such that the whole progressive failure process after excavation was reproduced. Based on the determined micro parameters for intact material and joint segments, the failure process around the circular opening agrees very well with that obtained through laboratory experiment. A subsequent parametric study was then carried out to look into the influence of lateral pressure coefficient, joint dip angle and joint persistency on the failure pattern and crack evolution of the rock mass around the circular opening. Three failure patterns identified are step path failure, planar failure and rotation failure depending on the lateral pressure coefficient. Moreover, the increment of joint dip angle and joint persistency aggravates the rock mass failure around the opening. This study offers guideline on stability estimation of underground excavations.

Numerical simulations of failure behavior around a circular opening in a non-persistently jointed rock mass under biaxial compression

Pre-existing discontinuities change the mechanical properties of rock masses,and further influence failure behavior around an underground opening.In present study,the failure behavior in both Inner and Outer zones around a circular opening in a non-persistently jointed rock mass under biaxial compression was investigated through numerical simulations.First,the micro parameters of the PFC^(3D) model were carefully calibrated using the macro mechanical properties determined in physical experiments implemented on jointed rock models.Then,a parametrical study was undertaken of the effect of stress condition,joint dip angle and joint persistency.Under low initial stress,the confining stress improves the mechanical behavior of the surrounding rock masses;while under high initial stress,the surrounding rock mass failed immediately following excavation.At small dip angles the cracks around the circular opening developed generally outwards in a step-path failure pattern;whereas,at high dip angles the surrounding rock mass failed in an instantaneous intact rock failure pattern.Moreover,the stability of the rock mass around the circular opening deteriorated significantly with increasing joint persistency.

Suicide risk in juvenile open angle glaucoma patients

AIM:To investigate the association between juvenile open angle glaucoma(JOAG)and mental health among Koreans.METHODS:This study used nationally representative data from the 8th Korea National Health and Nutrition Examination Survey(KNHANES)2021.Glaucoma diagnosis followed the International Society of Geographical and Epidemiological Ophthalmology criteria based on glaucomatous structural defects,visual field defects,corrected vision,and intraocular pressure.As outcomes,suicidal behaviors,psychiatric counseling,and depression were evaluated through mental health questionnaires.Odds ratios(ORs)with 95%confidence intervals(CIs)were estimated using logistic regression models,adjusting for covariates.RESULTS:Among 7090 participants,3446 met the inclusion criteria for analysis,and 88(2.6%)were diagnosed with open angle glaucoma(OAG).After adjusting for age,sex,and best-corrected visual acuity(VA),participants with OAG were revealed to have significantly higher odds of suicidal behaviors(i.e.,ideation,planning,or attempts)compared with those without OAG(OR:2.70;95%CI:1.12-6.54;P=0.028).This association remained significant after further adjustments for socioeconomic status,lifestyle factors,and presence of chronic conditions(P=0.031 and 0.035,respectively).However,there was no significant difference for the other two outcomes,psychiatric counseling and depression.An age-stratified analysis revealed a stronger association between OAG and suicidal behaviors in younger JOAG participants(<40y)than in older OAG participants(≥40y;OR:3.80 vs 2.22;95%CI:0.79-18.22 vs 0.56-8.80,respectively).CONCLUSION:OAG patients show a higher risk of suicidal behaviors than those without glaucoma particularly in JOAG patients.

Finite Element Modelling of Steel Beams with Web Openings

Height limitations are not uncommon in multi-storey buildings due to economic requirements and esthetical considerations. Substantial spaces are normally required to enable the passage of large pipes and ducts beneath steel beams leading to uneconomic floor heights. The most adopted solution for this issue is the use of steel beam web openings to provide the required space for services. These openings could lead to a significant decrease of the beam load carrying capacity depending on the adopted openings shape, size and location. These aspects motivated the present study based on FE simulations calibrated against numerical and test results. The results accuracy enabled a comprehensive parametric analysis of beams with web openings to be made focused on the profile size, web opening location, among others. The study also investigated the efficiency of longitudinal stiffeners welded at the opening region and benefits of using an adequate edge concordance radius in beams with rectangular and square openings. The obtained results showed the need of using welded longitudinal stiffeners in order to increase the beams ultimate load carrying capacity. This adoption can double or even triple the ultimate load of beams with rectangular and square opening heights equal to 0.75 H, respectively.

Research on Open Block's Pedestrian System Based on the EnvironmentBehavior Theory: A Case Study of Shenzhen Oct-loft

In the context of banning gated communities, blocks returning to the human-oriented scale become the new normal, and pedestrian system design will be paid more attention in the urban planning field. Oct-Loft Creative Park is a template for open blocks in Shenzhen, with a convenient and humanized pedestrian system. This paper selects the creative park's pedestrian system as the research object, using the environment-behavior theory for analysis. Finally, optimization strategies of pedestrian system will be put forward.

Shear Behavior of Open Steel Tube Connectors in Steel⁃UHPC Composite Decks

Steel and ultra⁃high performance concrete(UHPC)composite decks are effective at reducing fatigue cracking and asphalt pavement damage.The shear behavior of innovative open steel tube(OST)connectors in steel⁃UHPC composite decks was investigated by conducting push⁃out tests.The test parameter is the presence of reinforcement in the deck.The load⁃slip curves and shear behavior of the push⁃out specimens were obtained and discussed.The test results indicate that as compared with plain concrete specimens,the limit slip of reinforced specimens decreased by 32%and the shear stiffness increased by 10%,but the ultimate shear capacity was almost the same.The use of UHPC influenced the failure process as it was observed that the OST connector was sheared off at its lower semi⁃tube,followed by the pull⁃out failure of the upper semi⁃tube.A finite element model was verified by tests and was then used to analyze the deformation and failure behaviors of the composite deck with open tubes.The model demonstrates that there is a stress concentration zone at the connector root,and the lower semi⁃tube is the main component that is subject to loads.

数字化转型、开放式创新有效性与企业核心技术突破

加速数字化转型和推进开放式创新作为企业提升创新能力的重要策略,对于企业推进制造领域的核心技术突破同样至关重要。文章在筛选匹配企业研发专利数据与制造领域核心技术专利IPC分类号的基础上,基于2013—2021年A股上市企业数据,实证检验数字化转型对企业核心技术突破的推进作用以及开放式创新是否为该过程的有效传导机制。研究结果表明:数字化转型有助于企业推进制造领域的核心技术突破,企业推进开放式创新的具体程度会在此过程中发挥中介效应机制,且技术供给方企业、非国有企业和东部地区企业推进开放式创新的有效性更高;而企业是否推进开放式创新可能受其策略性行为影响,并不是有效的中介机制。进一步研究发现,金融科技发展水平和知识产权保护水平越高的地区,数字化转型背景下的开放式创新对企业核心技术突破的推进作用越强。本文不仅为企业通过数字化转型推进制造领域核心技术突破提供了新的研究思路,也侧面证明在数字化转型背景下更为重要的是企业推进开放式创新的具体程度和有效性,以及金融科技、知识产权保护等创新辅助要素对“新型举国体制”的赋能作用,进而为实现国家科技自立自强提供了有益对策启示。

基于Open Inventor的虚拟数控培训系统开发

针对传统数控培训中存在的场地受限、经费不足等问题,结合虚拟现实与人机交互等技术,提出了一种基于Open Inventor的数控培训系统实现方案。阐述了虚拟数控培训系统的软硬件开发平台,给出了软件系统的结构框架及开发流程。重点研究了虚拟加工场景的绘制及其模型优化、数控代码编译处理,给出事件处理的编程模型,并以直线进给为例阐述了机床的运动行为仿真。运用Open Inventor工具包在Visual C++6.0环境下实现初步原型系统,该系统运行效果良好。

开放性公共场所人员疏散行为倾向分析

开放性公共场所人群聚集风险突出,常规的疏散措施不能有效缓解场所内外的人群聚集风险态势,需要掌握突发情况人员疏散行为特征。选择深圳东门步行街为研究区,开展人员疏散行为问卷调查,根据人群聚集状态拟定人员疏导服从性、聚集拥堵应对和应急疏散响应3类疏散行为倾向场景,并采用SPSS 25.0卡方检验分析性别、年龄段、群组等基本特征与人员疏散行为倾向之间的相关性。研究结果表明:步行街存在老幼群体、携带包裹、环境熟悉度低等影响疏散效率的因素;小部分人在面对疏导、遭遇聚集拥堵情形后可能采取继续停留拍照、长时间等候、围观等聚集行为,以及在被疏散至安全地带后围观甚至返回,这些行为可能导致场所内部聚集得不到有效缓解,并在外围形成新的人群聚集风险点;“男性、大群组、短期游客”三类群体的疏散行为表现不佳,聚集围观、停留以及返回的比例更高,尤其是同行人数4人及以上的大群组更可能采取往前挤这种危害行为。

打开同行评议的“黑匣子”:专家评审行为特征分析

传统同行评议制度由于数据不透明、缺乏监督等问题饱受诟病,开放同行评议为揭开同行评议的黑盒、加强同行评议过程监督、规范评审行为提供了契机。文章基于Open Review平台2017-2019年ICLR会议的2,534篇论文及7,602份专家评审意见,结合定量和定性的方法从专家自信度、评审模式和论文评议结果等3个维度分析专家的评审行为特征分布。研究发现:在专家自信度上,自信度高的评审专家更了解论文的研究内容,更能给出差异化的评审打分和针对性的评审意见;在评审模式上,相较于单盲评审,双盲评审模式下评审专家打分更加严格,更少提及论文语言表达方面的不足;在评审决议结果维度上,评审专家对论文核心内容的评价是决定论文最终评议的重要依据,在实验设计和原创水平方面得到更多正面评价的论文,更有可能获得更好的评审决议。文章从评审专家的遴选、评审模式的选择和评审指标的设置等3个方面提出建议,以提高同行评议质量、推动同行评议改革。

宁心解郁胶囊对慢性应激抑郁模型大鼠Open-Field行为的影响

[目的]探讨宁心解郁胶囊的抗抑郁作用及可能的机制。[方法]以孤养加慢性轻度不可预见性应激方法建立大鼠抑郁模型,用Open-Field方法进行行为学评定,观察模型大鼠给药前后的行为学变化。[结果]经过孤养加慢性轻度不可预见性应激方法造模后的大鼠,Open-Field行为学评定中模型组大鼠的总路程、平均速度、中央活动路程、中央活动时间、各角的活动路程和时间均较空白组有统计学差异(P<0.05)。治疗后大鼠的总活动路程、平均速度、中央活动时间、中央活动路程、下边活动路程、下边活动时间、各角的活动路程和时间均较模型组有统计学差异(P<0.05),活动路程较模型组增加,活动时间较模型组增加,且以中剂量组效果显著。[结论]宁心解郁胶囊具有抗抑郁作用,对大鼠抑郁行为有明显改善。

应用OpenSees计算双钢管高强砼柱的水平力—位移滞回曲线

应用OpenSees计算外方内圆复合钢管高强混凝土柱(简称双钢管高强混凝土柱)的水平力—位移滞回曲线。分析了双钢管高强混凝土柱的单元和截面纤维划分。钢管材料采用双线性模型Steel02,混凝土模型采用Concrete02,圆钢管内和钢管之间的混凝土采用Susantha模型,考虑钢管对混凝土的约束作用,计算得到的水平力—位移滞回曲线与试验结果符合较好。在此基础上,应用OpenSees对双钢管高强混凝土柱进行参数影响分析,讨论了轴压比、方钢管壁厚(宽厚比)、径宽比、径厚比对双钢管高强混凝土柱抗震性能的影响。结果表明:增大轴压比,延性降低;增大方钢管壁厚(减小宽厚比),水平承载力增大;增大圆钢管直径和壁厚,有助于提高双钢管高强混凝土柱的竖向和水平承载力能力,增大耗能能力。

资本市场开放与企业策略性创新行为——基于外部监督的分析

文章立足于“沪港通”的制度背景,选取2010—2022年沪深A股非金融上市公司为研究对象,研究资本市场开放与企业策略性创新行为的关系。实证研究发现:第一,资本市场开放能提高授权专利中发明专利的占比,显著改善企业专利结构,提高专利质量;第二,从外部监督的角度机制分析发现,资本市场开放会通过增加监管机构和媒体监督产生聚光灯效应,进而减少通过策略性创新的市值管理行为;第三,动机分析发现,在资本市场开放下,企业出于防范崩盘风险和向市场传递特质性信息的目的,会减少策略性创新行为,提高专利质量;第四,资本市场开放对非国有企业和信息不对称较高的企业策略性创新行为抑制作用更加明显。本研究对于充分利用资本市场开放助力实体经济发展,推动企业实质性创新具有借鉴意义。

基于行为树的组网服务管控架构及调度方法

传统互联网为实现端到端安全、可靠、实时的网络业务保障,需要在网元节点部署多类组网服务。然而,现有大多数网络设备只提供网络接入和路由等服务功能,缺乏安全、可靠、实时的服务设计。基于开源网络操作系统(software for open networking in the cloud,SONiC)、容器技术和行为树设计一种组网服务管控架构及调度方法,实现面向网络业务保障的组网服务部署,将组网服务部署可编程网络设备进行统一管理和调度,并进行仿真测试。所述组网服务管控架构及调度方法进一步增强了网络设备能力,利用行为树高效协调管控调度过程中的状态转化,保障组网服务的交付质量。

面向社区生活圈的行为—设施时空匹配度评价--以南京市中心城区为例

从居民日常行为视角评估设施供需关系,是诊断生活圈范围内设施布局不合理问题的重要手段。已有研究主要从空间视角入手,较少考虑时间维度上的动态变化。基于居民行为活动差异进行时间段划分,利用POI数据和手机信令数据,提出一种面向社区生活圈的行为—设施时空匹配度评价思路,并以南京市中心城区为例进行研究。结果表明:尽管空间维度上设施供给、居民活动表现为显著的正相关,但时间维度上,二者出现明显的时空分异,部分时间段出现匹配错位情况。提出既可评估设施布局和居民活动的空间匹配模式,也可反映时间维度变化的方法,更综合地识别设施供需匹配上存在的问题,从而支撑设施时空配置和居民活动引导的策略。

短期大量摄入酒精对树鼩行为学及运动机能的影响

目的:探讨短期大量摄入酒精对树鼩行为学及运动机能的影响,为后续神经科学研究奠定基础。方法:用不同体积的50%乙醇溶液构建树鼩酒精暴饮模型。将20只雄性滇西树鼩随机分为对照组、低剂量组、中剂量组与高剂量组,每组5只。采用旷场试验、步态分析试验综合评价树鼩饮酒前后的行为学基本特征,比较3个剂量组的运动总距离、平均速度、最高速度、穿越中央区次数以及步态线性度Δα、交替系数β、步长规律系数σ。结果:旷场试验显示,与对照组相比,中、高剂量组的运动总距离、平均速度、最高速度均显著降低(均P<0.01),3个剂量组树鼩穿越中央区次数均显著减少(均P<0.01),且高剂量组的变化最为明显。步态分析显示,与对照组相比,中、高剂量组树鼩的步态线性度Δα均显著升高(均P<0.01),3个剂量组的交替系数β、步长规律系数σ均显著升高(均P<0.01),且高剂量组升高最为明显。结论:树鼩短期大量摄入酒精对其身体产生明显的镇静作用,表现为探索欲望降低,步态紊乱,甚至共济失调。

开放式创新平台激励与约束机制对用户创新行为的影响

平台的开放共享特征促使用户更主动地参与到价值创造活动中,企业吸纳用户参与创新过程成为其提升创新能力的重要途径。从认知—情感双重视角出发,以创新自我效能感、情感承诺为中介变量,以主动型人格为调节变量,探究开放式创新平台激励与约束机制对用户创新行为的影响机制及边界条件。结果显示,开放式创新平台激励机制、约束机制对用户创新行为均具有正向影响;创新自我效能感与情感承诺分别在开放式创新平台激励机制、约束机制与用户创新行为间发挥部分中介作用;主动型人格分别在开放式创新平台激励机制、约束机制与用户创新行为间发挥正向调节作用。

基于深度学习的复合材料开孔板拉伸失效行为预测

为研究复合材料开孔板在拉伸载荷下的失效行为,基于开孔板的拉伸试验建立了高精度的有限元仿真模型,并批量生成了拉伸载荷-位移曲线的数据集。提出了一种双长短时记忆(Long short-term memory,LSTM)神经网络模型用于预测载荷-位移曲线,其中第1个LSTM模型进行输入特征的提取,第2个LSTM模型直接给出载荷-位移曲线的预测。结果表明:这一模型能够高效、准确地预测开孔板的拉伸载荷-位移曲线,在测试集上的决定系数R2可以达到0.9755,关键特征如初始刚度E0的预测误差仅为1.85%,极限载荷Fmax的预测误差仅为2.16%。

基于三方演化博弈的科学数据开放共享主体行为策略分析

科学数据的开放共享既是开放科学的本质特征,也是中国大数据战略实施的重要环节。构建由科学数据的需求者、开放共享平台和提供者三方参与的博弈模型,系统探究了各主体间的合作竞争关系,并通过MATLAB软件仿真了系统策略的演化过程。重点分析了科学数据开放共享直接收益、科学数据寻求时间成本和科学数据开放共享平台收益3个关键变量的作用效果。结果表明:需求者为自身所需科学数据付费是促进科学数据开放共享的关键策略;平台监督机制以及给予提供者奖励与罚金的高低是影响科学数据提供方策略选择的重要因素。由此提出可以通过建立科学数据开放共享合理的付费机制,加强科学数据开放共享全生命周期安全监管,建立科学数据开放共享奖惩制度可以提升科学数据开放共享水平,推动中国科学数据开放共享进程。

促乙醇脱氢酶活性的小麦肽制备及其醒酒功效评价

为制备高醒酒活性的小麦肽,采用不同蛋白酶对小麦面筋蛋白进行酶解,以模拟胃肠道消化后对乙醇脱氢酶(alcohol dehydrogenase,ADH)激活率为指标进行酶解工艺研究。利用超滤和乙醇溶解分离技术,制备高促ADH活性的小麦肽,并通过动物实验进行醒酒功效评价。结果表明,胰蛋白酶酶解制备的小麦肽对ADH激活作用最显著,响应面优化得到最佳酶解条件为酶质量分数(E/S)0.5%、小麦面筋蛋白质量浓度7.0 mg/mL、酶解时间2.3 h;采用超滤分离获得分子质量为1~3 ku组分对ADH激活率最高,达到85.49%,进一步采用体积分数40%的乙醇溶解分离,其醇溶组分经模拟胃肠道消化处理后对ADH激活率达到120.3%;小鼠翻正反射及旷场精细行为实验表明,制备的小麦肽具有一定的醒酒功效,对小鼠酒后不适感,具有缓解作用。本研究可为小麦面筋蛋白醒酒肽的制备提供参考。