Fluorinated semi-interpenetrating polymer networks for enhancing the mechanical performance and storage stability of polymer-bonded explosives by controlling curing and phase separation rates

Herein, the effect of fluoropolymer binders on the properties of polymer-bonded explosives(PBXs) was comprehensively investigated. To this end, fluorinated semi-interpenetrating polymer networks(semiIPNs) were prepared using different catalyst amounts(denoted as F23-CLF-30-D). The involved curing and phase separation processes were monitored using Fourier-transform infrared spectroscopy, differential scanning calorimetry, a haze meter and a rheometer. Curing rate constant and activation energy were calculated using a theoretical model and numerical method, respectively. Results revealed that owing to its co-continuous micro-phase separation structure, the F23-CLF-30-D3 semi-IPN exhibited considerably higher tensile strength and elongation at break than pure fluororubber F2314 and the F23-CLF-30-D0 semi-IPN because the phase separation and curing rates matched in the initial stage of curing.An arc Brazilian test revealed that F23-CLF-30-D-based composites used as mock materials for PBXs exhibited excellent mechanical performance and storage stability. Thus, the matched curing and phase separation rates play a crucial role during the fabrication of high-performance semi-IPNs;these factors can be feasibly controlled using an appropriate catalyst amount.

Rock Mass Quality Rating Based on the Multi-Criteria Grey Metric Space

Assessment of rock mass quality significantly impacts the design and construction of underground and open-pit mines from the point of stability and economy.This study develops the novel Gromov-Hausdorff distance for rock quality(GHDQR)methodology for rock mass quality rating based on multi-criteria grey metric space.It usually presents the quality of surrounding rock by classes(metric spaces)with specified properties and adequate interval-grey numbers.Measuring the distance between surrounding rock sample characteristics and existing classes represents the core of this study.The Gromov-Hausdorff distance is an especially useful discriminant function,i.e.,a classifier to calculate these distances,and assess the quality of the surrounding rock.The efficiency of the developed methodology is analyzed using the Mean Absolute Percentage Error(MAPE)technique.Seven existing methods,such as the Gaussian cloud method,Discriminant method,Mutation series method,Artificial neural network(ANN),Support vector machine(SVM),Grey wolf optimizer and Support vector classification method(GWO-SVC)and Rock mass rating method(RMR)are used for comparison with the proposed GHDQR method.The share of the highly accurate category of 85.71%clearly indicates compliance with actual values obtained by the compared methods.The results of comparisons showed that the model enables objective,efficient,and reliable assessment of rock mass quality.

电动叶菜收获机速度协同控制系统设计与试验

针对电动叶菜收获机切割、输送和行走三者速度不协调导致的叶菜损伤率高、功耗大和收获效率低等问题,开发了一种电动叶菜收获机速度协同控制系统。系统以可编程逻辑控制器为核心,利用信息传感模块对割刀电机的电流、电压和转速进行数据采集;主控模块根据速度协同控制算法对采集信号进行处理,得到负载信息并协同切割、输送和行走三者速度。田间试验结果表明:系统稳定可靠,能够根据收获情况动态协同各部件速度参数,叶菜损伤率为8.88%;与传统定速控制方法相比,收获机功耗降低了13.1%,收获效率提升了33.4%。

一种新的P2P系统中基于双ratings的声誉管理机制

声誉系统的效率取决于回馈的质量,现有P2P系统中的声誉模型不能处理合谋、不递交ratings等攻击,并且对无过失节点还存在不公平性.针对这些问题,提出了一个新的基于双ratings的声誉管理机制.采用两个度量来评价节点:服务信任和回馈信任.服务信任反映server提供服务的可靠性;回馈信任反映consumer汇报ratings的可信度.一次交易后,要求服务双方都递交ratings,依据这两个ratings对server的服务信任和consumer的回馈信任进行更新,并且server的服务信任更新与consumer的回馈信任紧密相关.为了防止恶意节点反复实施恶意行为或不递交rating,还提出了一个惩罚机制,作为对声誉模型的补充.仿真表明,提出的声誉管理机制能够抵制上述恶意攻击,减少不公平性.

基于主题模型的(Aspect,Rating)摘要生成方法研究

提出基于短语参数学习的主题模型TMPP(Topic Model based on Phrase Parameter)对在线评论中被评价实体的aspect和与之对应的rating进行抽取.TMPP具有三个特点:1)评论用"短语袋"表示;2)将标准的LDA中表示文档-主题的参数扩展为(aspect,rating)集;3)融合了先验知识.介绍了TMPP模型参数的物理含义、模型的生成过程以及先验知识的获取和表示方法;阐述了在TMPP模型中引入方面集聚类使用先验知识的原因与好处、TMPP模型提取(方面,等级)对形成(aspect,rating)摘要的原理.以真实的在线产品评论数据集为实验对象,在实验过程中引入先验知识的方面识别分析和等级预测精度分析,列出了五类产品相关方面和对立的情感词的实验结果.通过与已有的基线方法比较,实验表明若评论集中每篇评论有一个总体等级,TMPP能产生高质量的(aspect,rating)摘要.

基于双目视觉技术的茶叶嫩芽定位方法研究

进一步提升茶叶嫩芽定位的准确性及茶叶嫩芽采摘的作业效率,选取双目视觉技术作为切入点,针对其识别、定位、采摘等环节展开设计研究。考虑茶叶嫩芽采摘的基础特征和双目视觉技术的应用条件,合理搭建双目视觉模型,选用立体匹配的核心定位算法,完成茶叶嫩芽的定位方法与采摘功能优化,并布置相应的试验机构,展开定位采摘验证试验。结果表明:基于双目视觉技术的茶叶嫩芽定位方法应用具有显著的优越性,较普通定位方法而言,识别误匹配率可降低至4.01%,平均漏采率为3.20%,嫩芽采摘完整率达93.40%,可以很好地促进茶叶嫩芽的后续处理加工,是采摘茶叶嫩芽的品质化的重要基础保障。

Structure design and simulation of MEMS vibrating ring gyroscope

MEMS gyroscope is a new inertial navigation sensor,which can measure the input angular rate of sensitive axis using Coriolis effect.Compared to the conventional gyroscope,it owns many unique advantages.A novel structure of vibrating ring gyroscope is proposed and the finite element model of the oscillator is established based on MEMS technology.Through the modal analysis,the natural frequency and mode shapes of the oscillator are obtained.By analyzing the effects of the structural parameters on the mode shapes and frequency of the harmonic oscillator,the optimal design parameters are got.The frequency difference between the operating mode and the other modes is greater than 1kHz after optimization,which can avoid the frequency coupling of the operating mode and other vibrating modes of the oscillator.The simulation results show that the performance parameters of the ring structure meet the design requirements and have obvious advantages.

钻孔联合地质剖面探测施工中若干问题探讨

基于《活动断层探测》GB/T 36072—2018、《活动断层探查钻探》DB/T 92—2022等现行规范规程,对跨隐伏活动断层的钻孔联合地质剖面探测施工的基本要求和存在的主要问题进行了探讨,认为现行技术标准存在的问题有:(1)对岩芯采取率的要求偏低;(2)对横跨隐伏逆断层的钻孔深度和钻孔之间距离的要求偏低.提出了下列改进措施:(1)各类岩土的岩芯采取率应大于现行技术标准要求的数值;其中,黏土的岩芯采取率应不小于99%;(2)对横跨隐伏逆断层的钻孔深度应大于现行技术标准要求的孔深;在第四系厚度较薄时,在逆断层上断点附近,位于逆断层上盘的钻孔在钻遇上盘的前第四系后,还应继续钻进,钻孔深度应达到能够揭露逆断层下盘的前第四系的深度;(3)当隐伏逆断层在第四系中的断距较小时,逆断层上断点两侧的2个相邻钻孔间距就需要1~3 m甚至更小的数值.补充了钻孔联合地质剖面探测中的钻孔布设方式、隐伏断层产状的求取方法.分析了在钻孔联合地质剖面探测的断层识别中存在的一些不确定性因素,并提出了相应对策.指出钻孔联合地质剖面探测施工是基于动态设计的信息化施工,现场技术负责人及其施工现场技术管理在钻孔联合地质剖面探测工作中起着重要作用.

Analysis of the Sensitivity of Probe EUB338 for Enumerating Eubacterial Cells

[Objective] This paper aimed to improve the detection rate of probe EUB338 for eubacteria.[Methods] Sixteen strains were used as materials for the experiment and analyzed through fluorescence in situ hybridization.[Result] The average detection rate of probe EUB338 was 63.9%,which can be increased to 71.3% through modified FISH.[Conclusion] This research was able to provide scientific basis for the detection of eubacteria in soil from the perspective of molecular biology.

基于大数据技术的大蒜品质智能化调控研究

以进一步提升大蒜种植的智能性、品质性为目标,选取大数据处理及应用技术,针对大蒜种植过程的调控系统展开设计。考虑大蒜种芽、种植土壤条件等基础特点,结合不同种植调控下的大蒜培育状况,基于大数据架构平台组成,搭建用于智能化品质大蒜调控的数据处理模型。设计布局大数据应用的软件控制模块,配置相应的系统硬件结构,重点针对种芽朝向进行调控。展开品质化作业试验,结果表明:基于大数据技术的大蒜品质智能化调控系统设计,能够很好地运用数据计算与处理算法对大蒜种植运动过程各数据进行准确监测,通过及时的调控措施满足种芽朝向调整正确率要求,单粒合格率可达到95.40%,蒜芽漏充率可降低至3.15%,种植效率相对提升了6.37%,具有很好的推广价值。

Machine learning applications in healthcare clinical practice and research

Machine learning(ML)is a type of artificial intelligence that assists computers in the acquisition of knowledge through data analysis,thus creating machines that can complete tasks otherwise requiring human intelligence.Among its various applications,it has proven groundbreaking in healthcare as well,both in clinical practice and research.In this editorial,we succinctly introduce ML applications and present a study,featured in the latest issue of the World Journal of Clinical Cases.The authors of this study conducted an analysis using both multiple linear regression(MLR)and ML methods to investigate the significant factors that may impact the estimated glomerular filtration rate in healthy women with and without non-alcoholic fatty liver disease(NAFLD).Their results implicated age as the most important determining factor in both groups,followed by lactic dehydrogenase,uric acid,forced expiratory volume in one second,and albumin.In addition,for the NAFLD-group,the 5th and 6th most important impact factors were thyroid-stimulating hormone and systolic blood pressure,as compared to plasma calcium and body fat for the NAFLD+group.However,the study's distinctive contribution lies in its adoption of ML methodologies,showcasing their superiority over traditional statistical approaches(herein MLR),thereby highlighting the potential of ML to represent an invaluable advanced adjunct tool in clinical practice and research.

围绝经期评定量表Menopause Rating Scale(MRS)中文版信度及效度分析

[目的]测定围绝经期评定量表(MRS)中文版的信度和效度。[方法]应用MRS中文版对126例围绝经期女性进行测量,对测定结果进行信度和效度分析。[结果]MRS中文版总的Cronbach′sα系数为0.890,3个维度的Cronbach′sα系数为0.731～0.868;总问卷的重测信度为0.887,3个维度的重测信度为0.661～0.883;探索性因子分析表明MRS中文版包括3个因子,共11个条目;3个因子可以解释总方差的73.68%;验证性因子分析显示数据拟合良好(χ2/df为1.170,近似误差均方根(RMSEA)为0.050,规范拟合指数(NFI)为0.894。[结论]MRS中文版具有良好的信度和效度,适合测量中国围绝经期妇女的生活质量。

替代率对某船用中速双燃料发动机性能的影响

为了改善某船用中速柴油机的燃油经济性和排放特性,对进气歧管加装天然气喷射装置的柴油/天然气双燃料发动机进行研究。基于仿真软件GT-Power,在螺旋桨推进特性的工况下,分析了某船用双燃料发动机纯柴油模式和双燃料模式下的缸内压力、燃油经济性和排放特性。结果表明:与纯柴油模式相比,双燃料模式的气缸峰值压力和NO_(x)排放量有所减少,NO_(x)排放量最多减少41.3%;随着天然气替代率的增加,发动机的燃油经济性最多提高了16.08%。综合来看,双燃料模式下发动机性能得到提升。

DYNAMIC CHARACTERISTICS OF LARGE FLOW RATING ELECTROHYDRAULIC PROPORTIONAL CARTRIDGE VALVE

A kind of cartridge servo proportional valve is discussed, which can be used for controlling large flow rate with high performance. By analyzing the structure principle of the valve, the transfer fimction of the valve is derived. With the transfer function, some structure elements that may affect its performance are investigated. Through the numerical simulation and test study, some principles of optimality and effective methods for improving the dynamic performance of the valve are proposed. The test results conform to the results of the theoretical analysis and simulation, which proves the correctness of the study and simulation works. The paper provides theoretical basis for engineering applications and series expanding design works

Physical simulation and theoretical analysis of migrating rate of inclusions in aluminum melt in electromagnetic field

Simulation law and physical simulation were used to study the kinematic behavior of inclusions in electromagnetic separation. It was found that velocity of spherical non metallic particles shares different functions in different Reynolds number range. The function of spherical particle’s velocity has been got by confirming the relationship between Reynolds number and resistance coefficient when Reynolds number is 0.2 ～10. For non spherical particles, the moving behavior is influenced by shape and orientation while spherical coefficient has nothing to do with the velocity of irregular particles. The influence of orientation of cuboid particle on the electromagnetic expulsive force has been indicated by numerical computation. [

Rating Curve Estimation of Surface Water Quality Data Using LOADEST

Measurement of the nutrient concentrations in the stream is usually done on weekly, biweekly or monthly basis due to limited resources. There is need to estimate concentration and loads during the period when no data is available. The objectives of this study were to test the performance of a suite of regression models in predicting continuous water quality loading data and to determine systematic biases in the prediction. This study used the LOADEST model which includes several predefined regression models that specify the model form and complexity. Water quality data primarily nitrogen and phosphorus from five monitoring stations in the Neuse River Basin in North Carolina, USA were used in the development and analyses of rating curves. We found that LOADEST performed generally well in predicting loads and observation trends with general tendency/bias towards overestimation. Estimated Total Nitrogen (TN) varied from observation (“true” load) by -1% to 9%, but for the Total Phosphorus (TP) it ranged from -2% to 27%. Statistical evaluation using R2, Nash-Sutcliff Efficiency (NSE) and Partial Load Factor (PLF) showed a strong correlation in prediction.

腹部推拿对阈下抑郁大学生自主神经功能调控的临床研究

目的:探究腹部推拿对阈下抑郁大学生自主神经功能的调控作用。方法:选取2022年9月~2023年12月于湖南中医药大学招募的阈下抑郁大学生64例,并随机分为腹部推拿组与对照组各32例;最终完成试验的受试者为,腹部推拿组31例,对照组29例。腹部推拿组以摩腹、按揉腹部、振腹三种手法进行操作,对照组则在腹部予以静止性触摸,每周一、三、五各干预1次,每次25 min,共6周。观察两组受试者干预前后及1个月随访时汉密尔顿抑郁量表17项版(HAMD-17)评分,干预前后心率变异性(HRV)时域指标SDNN、RMSSD、pNN50及频域指标VLF、LF、HF、LF/HF的变化,以及两组临床疗效。结果:治疗后,腹部推拿组患者HAMD-17评分较治疗前显著降低(P<0.01),对照组患者HAMD-17评分较治疗前降低(P<0.05),且腹部推拿组患者HAMD-17评分显著低于对照组(P<0.01);1个月随访时,腹部推拿组HAMD-17评分仍维持治疗后水平,且显著低于对照组(P<0.01):而对照组HAMD-17评分逐渐回升,与治疗前相比差异无统计学意义(P>0.05)。治疗后,腹部推拿组SDNN、RMSSD、pNN50较治疗前显著升高(P<0.01),对照组SDNN、RMSSD、pNN50较治疗前有升高趋势,但差异无统计学意义(P>0.05),且腹部推拿组SDNN、RMSSD、pNN50均高于对照组(P<0.01)。治疗后,腹部推拿组VLF、LF较治疗前升高(P<0.01)、HF较治疗前升高(P<0.05),LF/HF较治疗前降低(P<0.05);对照组VLF、LF、HF较治疗前有升高趋势,LF/HF较治疗前有降低趋势,但差异均无统计学意义(P>0.05);且腹部推拿组VLF、LF均显著高于对照组(P<0.01),HF高于对照组(P<0.05)、LF/HF低于对照组(P<0.05)。腹部推拿组总有效率高于对照组(P<0.01)。结论:腹部推拿能够改善抑郁情绪,并能调控自主神经功能,尤其是激活副交感神经。

Modification of rock mass rating system:Interbedding of strong and weak rock layers

Rock mass classification systems are the very important part for underground projects and rock mass rating(RMR) is one of the most commonly applied classification systems in numerous civil and mining projects. The type of rock mass consisting of an interbedding of strong and weak layers poses difficulties and uncertainties for determining the RMR. For this, the present paper uses the concept of rock bolt supporting factor(RSF) for modification of RMR system to be used in such rock mass types. The proposed method also demonstrates the importance of rock bolting practice in such rock masses. The geological parameters of the Shemshak Formation of the Alborz Tunnel in Iran are used as case examples for development of the theoretical approach.

STABILIZATION OF VIBRATING BEAM BY VELOCITY FEEDBACK CONTROL

A flexible structure consisting of a Euler-Bernoulli beam with co-located sensors and actuators is considered. The control is a shear force in proportion to velocity. It is known that uniform exponential stability can be achieved with velocity feedback. A sensitivity asymptotic analysis of the system's eigenvalues and eigenfunctions is set up. The authors prove that, for K-1 epsilon (0, + infinity), all of the generalized eigenvectors of A form a Riesz basis of H. It is also proved that the optimal exponential decay rate can be obtained from the spectrum of the system for 0 < K-1 < + infinity.

Accelerating Effect of Wetting-Drying Cycles on Steel Bar Corrosion in Concrete

Raining and sun-shining processes in natural climate were simulated by water spraying and infrared lightshining alternately as wetting-drying cycles in accelerated durability test. The accelerating effects of the wet-ting-drying cycles and the variation of corrosion current density and corrosion potential of steel bar in concrete undersuch conditions were studied. The result shows that the main reason leading to accelerating corrosion of steel bar inconcrete is the wetting-drying cycles, which can cause the increase of corrosion potential difference between the an-ode and cathode of steel bar corrosion cell and the decrease of concrete resistance. Corrosion rate of the steel bar inconcrete under four typical conditions, including wetting-drying cycle, long time submerging in water, long time ex-posure to indoor and outdoor environment were measured and compared. The test results indicate that the corrosionrates under the four typical conditions are in the order of spraying and infrared light shining cycles, outdoor environ-ment, indoor environment, and submerging in water, respectively.