Vote-Based Feature Selection Method for Stratigraphic Recognition in Tunnelling Process of Shield Machine

Shield machines are currently the main tool for underground tunnel construction. Due to the complexity and variability of the underground construction environment, it is necessary to accurately identify the ground in real-time during the tunnel construction process to match and adjust the tunnel parameters according to the geological conditions to ensure construction safety. Compared with the traditional method of stratum identifcation based on staged drilling sampling, the real-time stratum identifcation method based on construction data has the advantages of low cost and high precision. Due to the huge amount of sensor data of the ultra-large diameter mud-water balance shield machine, in order to balance the identifcation time and recognition accuracy of the formation, it is necessary to screen the multivariate data features collected by hundreds of sensors. In response to this problem, this paper proposes a voting-based feature extraction method (VFS), which integrates multiple feature extraction algorithms FSM, and the frequency of each feature in all feature extraction algorithms is the basis for voting. At the same time, in order to verify the wide applicability of the method, several commonly used classifcation models are used to train and test the obtained efective feature data, and the model accuracy and recognition time are used as evaluation indicators, and the classifcation with the best combination with VFS is obtained. The experimental results of shield machine data of 6 diferent geological structures show that the average accuracy of 13 features obtained by VFS combined with diferent classifcation algorithms is 91%;among them, the random forest model takes less time and has the highest recognition accuracy, reaching 93%, showing best compatibility with VFS. Therefore, the VFS algorithm proposed in this paper has high reliability and wide applicability for stratum identifcation in the process of tunnel construction, and can be matched with a variety of classifer algorithms. By combining 13 features selected from shield machine data features with random forest, the identifcation of the construction stratum environment of shield tunnels can be well realized, and further theoretical guidance for underground engineering construction can be provided.

数据安全防护体系在高校校园网中的应用

在高校网络的基本组成结构中,校园网具有保障高校数据信息得以安全稳定传输的重要作用,校园网目前已成为高校师生赖以实现沟通联系的基础设施支撑。目前在网络技术的快速转型以及发展趋势作用下,高校校园网日益存在更加突出的网络数据安全威胁,进而体现全面防范以及科学预测校园网数据安全隐患的必要性。文章主要探讨高校校园网构建数据安全防护体系的实践价值,合理改进校园网现有的数据传输安全保障机制。

儿童青少年高尿酸血症患病情况及相关因素分析

目的:调查内蒙古包头市区儿童青少年高尿酸血症(HUA)患病情况及相关因素。方法:收集2021年1月至2022年6月就诊于包头市三区三级医院儿科、风湿免疫科的3~18岁儿童青少年资料,将其中符合研究标准的作为研究对象,整理资料并对结果进行统计分析。结果:不同性别、年龄段之间SUA水平差异有统计学意义(P<0.05);在3~6岁,7~9岁,10~18岁年龄段,男生HUA检出率分别为4.93%,3.21%,4.41%,女生HUA检出率分别为4.44%,3%,2%;在男生中,HUA组与正常组的尿素氮(BUN)、肌酐(Cr)、天门冬氨酸氨基转移酶(AST)、血糖(Glu)、血脂水平差异有统计学意义(P<0.05);在女生中,HUA组与正常组的AST水平差异有统计学意义(P<0.05)。相关性分析结果显示,男生SUA水平与尿素氮(BUN)、肌酐(Cr)、丙氨酸氨基转移酶(ALT)、甘油三酯(TG)、总胆固醇(TC)呈正相关(P<0.05);女生SUA水平与Glu呈负相关(P<0.05),与BUN、Cr、ALT呈正相关(P<0.05)。多因素Logistic回归分析结果显示,BUN、TC是男生HUA的影响因素,Glu是女生HUA的影响因素。结论:包头市区儿童青少年血尿酸水平在不同年龄和性别中存在差异,男生高尿酸血症检出率较女生高;高尿酸血症可引起BUN、Cr、AST、Glu、血脂水平变化;TC、BUN、Glu是儿童青少年高尿酸血症的影响因素。

疏解工艺对簕竹重组材力学性能及尺寸稳定性的影响

本文以簕竹为原料制备重组材,研究了不同疏解工艺对簕竹重组材力学性能和尺寸稳定性的影响,并通过与毛竹重组材对比,探讨其利用价值。结果表明:随着疏解程度的增加,竹束的载胶量增大,竹青竹黄的存在使竹束对胶黏剂的吸附能力下降;相同条件下,簕竹重组材与毛竹重组材水平剪切强度相当,弹性模量及静曲强度约为毛竹的2倍左右,经28 h循环水处理吸水厚度膨胀率约为毛竹的1/2;带青带黄疏解有利于提高簕竹重组材的抗弯性能,制备的重组竹静曲强度达215 MPa,弹性模量达28 GPa,分别高于常规疏解的8.64%和12.92%,但其水平剪切强度略有下降。竹青的存在可以提高簕竹表面的耐水性,簕竹青黄宽疏解在60 s时接触角仍能达到60°,较其余条件耐水性高。以簕竹开发制备重组材在工程应用上具有较大潜力。

一种自复位摇摆墙的改进Bouc-Wen滞回模型

Bouc-Wen模型是一种可表征结构及构件刚度、强度退化等的多功能非线性光滑滞回模型,可广泛应用于各类结构滞回行为的描述。自复位摇摆墙(Self-centering rocking wall, SCRW)结构由于其优越的抗震和自复位性能,滞回曲线呈“旗帜型”。为了更好地表征这种“旗帜型”滞回特性,在Bouc-Wen模型的基础上,建立一种具有较高精度和较好实用性的改进Bouc-Wen滞回模型。改进的Bouc-Wen模型参数是决定结构滞回性能力学特征的关键。由于该模型参数众多且选择范围不明确,为适应该类模型参数高效识别的需求,通过在MATLAB/Simulink环境中搭建程序框图,实现了对该理论模型控制参数的定性及定量分析,并运用遗传算法对10个SCRW试验结果进行参数识别,对识别结果进行统计分析,建立各参数与滞回曲线关键点的关系式,基于统计结果给出了各参数的建议取值范围;最后,通过SCRW拟静力试验对改进的滞回模型和参数取值范围进行了验证。结果表明:这种单自由度改进的Bouc-Wen滞回模型能较好地反映SCRW在往复荷载作用下无残余变形和强度、刚度退化特点的“旗帜型”滞回特性。所提出的参数取值范围显著提升了改进Bouc-Wen模型的识别精度与效率,识别过程对类似模型的参数识别具有参考价值。

不同血液分离结果的多发性骨髓瘤骨病患者骨代谢水平研究

目的:探讨不同血液分离结果的骨髓瘤骨病(MBD)患者骨代谢指标对病情评估及疗效监测的临床意义。方法:纳入2016年3月至2020年3月河北省沧州中西医结合医院收治的134例初诊MM患者,根据血液离心结果,分为对照组119例(样本自上而下依次为血清、胶体、红细胞),异常组15例(样本自上而下依次为血清、红细胞、胶体、红细胞),根据影像学表现将MBD分为0-4级,0-2级为骨病较轻者,3-4级为骨病较重者,分析两组患者MBD的分级情况,并对不同血液分离结果的MBD患者进行疗效评价,分析治疗前后血液分离结果及骨代谢指标水平的变化,采用Pearson相关分析法分析β2-微球蛋白(MG)与骨代谢指标水平的相关性。结果:对照组0-2级69例,3-4级50例;异常组0-2级5例,3-4级10例,比较差异具有统计学意义(P<0.05)。异常组血清β2-MG、Ⅰ型胶原羧基端肽β特殊序列(β-CTX)水平显著高于对照组,而Ⅰ型前胶原氨基端前肽(P1NP)、骨钙素(OC)水平显著低于对照组(均P<0.001)。对照组95例疗效≥部分缓解(PR),其血液分离结果未改变;24例疗效<PR,其中5例血液分离结果转为异常。异常组9例疗效≥PR,血液分离结果均转为正常;6例疗效<PR,其中5例血液分离结果仍为异常。与治疗前相比,对照组疗效≥PR的患者β-CTX、β2-MG水平显著降低,而P1NP、OC水平显著升高(均P<0.001);异常组疗效≥PR的患者β-CTX、β2-MG水平亦显著降低(P<0.001,P<0.01),而P1NP、OC水平显著升高(P<0.001,P<0.01)。两组疗效<PR的患者各指标水平与治疗前相比无明显变化(P>0.05)。与疗前相比,对照组治疗后血液分离结果未改变的患者β-CTX、β2-MG水平显著降低(均P<0.001),P1NP、OC水平显著升高(P<0.01,P<0.001),而血液分离结果转为异常的患者各指标水平无明显变化(P>0.05);异常组治疗后血液分离结果转为正常的患者β-CTX、β2-MG水平显著降低(均P<0.01),P1NP、OC水平显著升高(P<0.001,P<0.01),而血液分离结果未改变的患者各指标水平无明显变化。Pearson相关分析显示,患者血清β2-MG与β-CTX水平呈正相关(r=0.709,P<0.001),与P1NP、OC水平呈负相关(r=-0.410、-0.412,均P<0.001)。结论:存在血液异常分离结果的MBD患者骨病分级较高、预后较差,与骨吸收指标β-CTX水平显著升高,骨形成指标P1NP、OC水平显著降低,引起更严重的骨代谢动态平衡紊乱密切相关。血液分离结果联合骨代谢指标水平的变化可作为MBD患者病情、疗效监测及预后评估的综合预测指标之一。

基于分布参数模型的摇摆墙-框架结构协同性能分析

为了研究自复位摇摆墙-框架(rocking wall-moment frame,RWMF)结构的协同工作性能,利用所提出的分布参数模型对自复位RWMF结构的协同工作原理与基本影响规律进行研究,建立并求解了完整的静力和动力方程;得到RWMF结构的侧移、内力和各阶动态响应的闭合解,通过参数分析研究框架与摇摆墙(rocking wall,RW)之间的刚度特征值λ和RW底部旋转约束R_(f)对协同性能的影响,并采用层间位移集中系数(inter-story drift concentration factor,DCF)量化RW与框架之间的协同性能。结果表明:RW的设计应满足λ<10,否则,RW对协同性能的影响将微乎其微;当λ值适中时,RW底部约束可以增进协同作用,R_(f)>5后,其约束的继续增大不会再增进RW与框架间的协同效果;当λ和R_(f)取1≤λ≤5∩0.1<R_(f)≤10时,自复位RWMF结构可以在分布均匀性和减小主体框架损伤之间实现平衡,达到最优的协同性能。

不同玉米秸秆还田方式对土壤化学性质及烤烟产量的影响

玉米秸秆还田不仅可以使农业废弃物高效资源化利用,还可以有效改善烤烟种植过程中田间管理不合理导致的土壤肥力下降和功能退化的状况。本试验共设4个处理(分别为秸秆深埋、深松、粉垄30 cm、粉垄50 cm处理),探究了不同玉米秸秆还田方式对土壤化学性质及烤烟产量的影响。结果表明:粉垄50 cm处理土壤有机质、硝态氮、铵态氮、速效钾、土壤碳氮比提升效果最好;各处理烟叶氮、磷元素含量差异不显著,深松与粉垄50 cm处理烟叶产量较高;粉垄50 cm处理烟株上等烟比例最大,深松、粉垄50 cm处理烟叶产值较高。因此,粉垄50 cm玉米秸秆还田方式可以有效提高土壤营养元素含量,提升烟叶品质,显著增加烟叶产值。

基于改进阻性下垂控制的分布式储能系统SOC均衡策略

低压微电网运行时,由于各分布式储能单元初始状态不一致和输出线路阻抗差异,采用传统阻性下垂控制易出现荷电状态(state of charge,SOC)不平衡问题,由此提出一种基于改进阻性下垂控制的储能系统SOC均衡策略。该策略首先引入动态虚拟复阻抗,消除各逆变器输出线路阻抗差异,实现阻性下垂控制功率解耦和有功功率精确均分。然后改进传统阻性下垂控制方程,通过各分布式储能单元的SOC变化自适应调整下垂系数,确保低压微电网各储能单元在充放电过程的SOC平衡,并对下垂控制过程中的电压与频率偏差进行补偿,进一步提升系统稳定性。最后,通过搭建仿真模型验证了所提策略的有效性。

Resilient performance of self-centering hybrid rocking walls with curved interface under pseudo-static loading

Frame and rocking wall(FRW)structures have excellent resilient performance during earthquakes.However,the concrete at interfacial corners of rocking walls(RWs)is easily crushed due to local extreme compression during the rocking process.An innovative RW with a curved interface is proposed to prevent interfacial corners from producing local damage,enhancing its earthquake resilient performance(ERP).The precast wall panel with a curved interface is assembled into an integral self-centering hybrid rocking wall(SCRW)by two post-tensioned unbonded prestressed tendons.Moreover,two ordinary energy dissipation steel rebars and two shear reinforcements are arranged to increase the energy dissipation capacity and lateral resistance.Two SCRW specimens and one monolithic reinforced concrete(RC)shear wall(SW)were tested under pseudo-static loading to compare the ERPs of the proposed SCRW and the SW,focusing on studying the effect of the curved interface on the SCRW.The key resilient performance of rocking effects,failure modes,and hysteretic properties of the SCRW were explored.The results show that nonlinear deformations of the SCRW are concentrated along the interface between the SCRW and the foundation,avoiding damage within the SCRW.The restoring force provided by the prestressed tendons can effectively realize self-centering capacity with small residual deformation,and the resilient performance of the SCRW is better than that of monolithic SW.In addition,the curved interface of the SCRW makes the rocking center change and move inward,partially relieving the stress concentration and crush of concrete.The rocking range of the rocking center is about 41.4%of the width of the SCRW.

A 1-bit electronically reconfigurable beam steerable metasurface reflectarray with multiple polarization manipulations

A 1-bit electronically controlled metasurface reflectarray is presented to achieve beam steering with multiple polarization manipulations. A metsurface unit cell loaded by two PIN diodes is designed. By switching the two PIN diodes between ON and OFF states, the isotropic and anisotropic reflections can be flexibly achieved. For either the isotropic reflection or the anisotropic reflection, the two operation states achieve the reflection coefficients with approximately equal magnitude and 180°out of phase, thus giving rise to the isotropic/anisotropic 1-bit metasurface unit cells. With the 1-bit unit cells, a 12-by-12 metasurface reflectarray is optimally designed and fabricated. Under either y-or x-polarized incident wave illumination, the reflectarray can achieve the co-polarized and cross-polarized beam scanning, respectively, with the peak gains of 20.08 d Bi and 17.26 d Bi within the scan range of about ±50°. With the right-handed circular polarization(RHCP) excitation, the left-handed circular polarization(LHCP) radiation with the peak gain of 16.98 d Bic can be achieved within the scan range of ±50°. Good agreement between the experimental results and the simulation results are observed for 2D beam steering and polarization manipulation capabilities.

Meiotic nuclear divisions 1 suppresses the proliferation and invasion of pancreatic cancer cells via regulating H2A.X variant histone

Introduction:Among all malignant tumors of the digestive system,pancreatic carcinoma exhibits the highest mortality rate.Currently,prevention and effective treatment are urgent issues that need to be addressed.Methods:The study focused on meiotic nuclear divisions 1(MND1),integrating data from the Gene Expression Profiling Interactive Analysis(GEPIA)database with prognostic survival analysis.Simultaneously,experiments at cellular level were employed to demonstrate the effect of MND1 on the proliferation and migration of PC.The small-molecule inhibitor of MND1 was used to suppress the migration of PC cells by knocking down MND1 using small interfering RNA(siRNA)in Patu-8988 and Panc1 cell lines.Results:The results of Cell Counting Kit-8 indicated that the suppression of MND1 resulted in a decrease in cell proliferation.Wound healing and Transwell assays revealed that MND1 knockdown reduced cell migration and invasion.Flow cytometry revealed that inhibiting MND1 hindered the cell cycle.Furthermore,MND1 could stimulate the proliferation,migration,and invasion of Patu-8988 and Panc1 cells by increasing the expression of MND1.Notably,MND1 had a positive effect on H2AFX expression in PC cells.Elevated MND1 expression suggests the low overall survival rate of individuals diagnosed with PC.Conclusion:These findings suggest that MND1 has the potential to be a gene with the ability to accurately diagnose and treat PC.

Low-Carbon Dispatch of an Integrated Energy System Considering Confidence Intervals for Renewable Energy Generation

Addressing the insufficiency in down-regulation leeway within integrated energy systems stemming from the erratic and volatile nature of wind and solar renewable energy generation,this study focuses on formulating a coordinated strategy involving the carbon capture unit of the integrated energy system and the resources on the load storage side.A scheduling model is devised that takes into account the confidence interval associated with renewable energy generation,with the overarching goal of optimizing the system for low-carbon operation.To begin with,an in-depth analysis is conducted on the temporal energy-shifting attributes and the low-carbon modulation mechanisms exhibited by the source-side carbon capture power plant within the context of integrated and adaptable operational paradigms.Drawing from this analysis,a model is devised to represent the adjustable resources on the charge-storage side,predicated on the principles of electro-thermal coupling within the energy system.Subsequently,the dissimilarities in the confidence intervals of renewable energy generation are considered,leading to the proposition of a flexible upper threshold for the confidence interval.Building on this,a low-carbon dispatch model is established for the integrated energy system,factoring in the margin allowed by the adjustable resources.In the final phase,a simulation is performed on a regional electric heating integrated energy system.This simulation seeks to assess the impact of source-load-storage coordination on the system’s low-carbon operation across various scenarios of reduction margin reserves.The findings underscore that the proactive scheduling model incorporating confidence interval considerations for reduction margin reserves effectively mitigates the uncertainties tied to renewable energy generation.Through harmonized orchestration of source,load,and storage elements,it expands the utilization scope for renewable energy,safeguards the economic efficiency of system operations under low-carbon emission conditions,and empirically validates the soundness and efficacy of the proposed approach.

冬奥会徽图像符号对国家形象建构价值研究

文章以图像符号学的视角切入,通过对历届冬奥会徽图案的解读与分析,继而将冬奥会徽分为抽象几何图案类型、客观具象图案类型、融汇装饰图案类型、现代创意图案类型,并从中解析冬奥会徽图案设计理念对国家形象建构的价值功能。研究表明:冬奥会徽记载自然地理事物和国家领土空间,强化公民对国家兴衰负有的历史责任与使命担当;冬奥会徽传达了一个国家的声音,蕴含了一个民族的精神风貌,对激发爱国热情与情感联结,树牢民族共同体意识有聚焦作用;会徽记录着民族危难、唤醒公民铭记历史情怀,为国家形象的建构奠定共同而稳定的人民基础。

基于OBE理念的“模拟电子线路”课程混合式教学改革——以兰州大学为例

文章基于OBE理念,结合兰州大学的办学定位和专业特色,充分利用线上、线下教学优势,以学生学习成果为导向,遵循反向设计、正向实施的原则,深入研究了“模拟电子线路”课程的教学目标、教学内容、混合式教学实施方案以及考核与评价细则。结合自建的SPOC平台资源,创设适切的教学环境,注重因材施教,强化课程育人,不断探索“利于学”的教学新模式,引导学生主动参与学习,实现全过程、全方位考核,以提升课程的高阶性、创新性和挑战度。

远程手术创新的现状和进展

远程手术是指外科医师使用无线网络和机器人技术为远在异地的患者做手术,属于远程医疗的一部分。远程手术不仅可以缓解区域外科医师短缺的情况,而且能打破空间壁垒,及时、有效地开展手术,降低医疗成本和患者转运风险。远程手术的发展需要5G网络技术和手术机器人技术的双重辅助。本文分析了5G网络技术和计算机辅助技术在远程手术中的应用与限制,总结了远程手术创新发展的现状和进展,为远程手术的发展提供更多思路。

基于改进蚁群动态规划的光储微网容量优化配置

为降低并网光储微网的综合发电成本,并提高优化容量配置性能,该文研究基于改进蚁群动态规划算法的光储微网容量优化配置方法。针对传统启发式算法容易陷入局部最优以及早熟收敛的问题,首先将蚁群算法与动态规划算法结合,简化计算过程;进而,将迭代次数有关的衰减参数引入调节因子中,提高其全局搜索能力;最后,将Boltzmann选择机制引进蚁群搜索过程,并在蚁群信息素更新过程中采用偏转角度因子与拐点参数进行修正,从而大幅提高算法的优化性能。通过对海宁某小区实际数据进行仿真分析,验证了该算法的实用性和优越性。

缓慢加热条件下壳装PBX炸药响应特性研究

为了研究弹药在热刺激作用下的响应规律,进行了壳装PBX炸药慢速烤燃试验,获得了1 K/min升温速率下壳体内部的压力-时间曲线,壳体内部压力变化过程表现为炸药热分解产气段、点火燃烧段和壳体破裂段3个阶段。提出了一种模拟计算慢速烤燃时壳装PBX炸药发生低等级响应过程的理论方法,首先计算炸药点火前的温度场分布,引入热分解系数k描述炸药热分解消耗的程度,在此基础上建立改进的内弹道方程组,模拟计算了因炸药点火燃烧导致壳体内部压力快速上升的行为,理论值和试验值吻合良好,随后应用LS-DYNA软件模拟了壳体在内部压力作用下的破裂行为。计算了1.0~10.0 K/min之间6种不同升温速率条件下炸药点火后的压力-时间曲线,当升温速率为1.0 K/min时,炸药点火后压力增长速率明显高于其他工况。

基于胜任力模型的后勤管理队伍全流程培养体系构建与实践

目的基于胜任力模型建立符合医院后勤管理者培养、考核、评价、晋升全流程综合培养体系。方法以文献研究、岗位说明书、STAR访谈及专家讨论结果为依据构建后勤管理者胜任力模型,将其7大维度24个胜任力要素作为标准体系进行实际应用,衍生出识别与筛选、培养与发展、考核与评价、淘汰与晋升四个模块,具体结合360度评价、KPI评价等方法,反馈回标准体系形成闭环。结果构建基于胜任力模型的后勤管理者绩效考核体系。结论经实践证明,以胜任力模型为基础的综合培养体系不仅提升了后勤管理者的综合能力,也保证了管理业绩的持续实现,是契合医院后勤变革发展的有效路径。

基于C5.0算法对以太坊中非法账户的分析与预测

针对加密货币的匿名性使得非法交易行为难于跟踪分析的问题,以以太坊交易数据为数据源,以被标记的非法账户和未标记的正常账户数据集作为训练集,基于C5.0算法,对其中包含多种类型的非法账户进行预测。实验过程采用多倍交叉验证,预测准确率达到了90.06%,感受者曲线下面积数值的评估度量达到了0.945。所提方案能够较为准确地预测以太坊交易平台上存在的非法行为,有效改善了基于区块链的交易环境。