RESEARCH ON A NEW TYPE OF MACHINABLE BIOACTIVE GLASS-CERAMICS

A new type of machinable bioactive glass-ceramics for bone substitution has been developed in the glass system SiO_2-MgO-K_2O-F^--CaO-P_2O_5, which contains Mg- muscovite [K_2Mg_5 (Si_8O_(20)) F_4] and fluorapatite as the two main crystal phases. The phase separation and the crystallization of the glass have been studied. A series of tests have showed that the material is good at mechanical property and bioactivity. Espe- cially, by analysing the structure of the interface layer between the material and the bone of animal with scanning electron microscope, electron probe, etc., it has been found that the new bone hydroxya- patite is formed on the surface of the material so that the material is connected firmly with the bone.

A research on building block type miniature harvester

In this invention, the procedure of cutting, conveying, threshing and transporting stalks are carried out by a set of conveying chains ( see figure). The axis of the main drum 2 is placed horizontally transverse (vertical to the forward direction). The upper and the lower conveying chains 8, 10 as well as cutterbar 11 are mounted in the lower part of the axial feed opening. Several star well 9 and plastic stalk-pressing rod are filled at the front of the lower conveying chain, and a spring stalk pressing assembly at the rear. The residue after threshing is discharged by star seels 18, 34. The staiks are placed near the cutterbar 11. Once the stalks are cut off by the cutterbar, they

A research on invasion of different types of meningeomas to their surrounding tissue

Objective To explore the invasion of different types of meningeoma to their surrounding tissue. Methods The specimen from 124 patients with meningeomas,who underwent surgery in Southern Hospital from April 2009 to June 2010 were used to analyze the invasion of different types of meningeomas to their surrounding tissue. All the tumors were resected in the standard of Simposon I. We referred to WHO 2007

海洋环境下铝合金腐蚀与防护的研究进展探析

铝合金因具有较好的耐蚀性能和加工性能,并且本身也具有质量轻、强度好等优点,在海洋船舶和海洋工程装备等领域得到了非常广泛的应用。随着对海洋资源的探索,船舶及海洋工程装备领域迎来了快速发展时期。由于海洋环境的特殊性和复杂性,在深海或者极端环境下铝合金也有广泛应用的可能性,在深海油气勘探和极地航行船舶等设备中,铝合金可以作为结构材料,因其质量轻、耐腐蚀性能好,得到了广泛应用,但存在着诸多腐蚀铝合金的因素,给船舶及海洋工程装备的发展造成严重的影响。基于国内外最新相关研究进展,针对铝合金的种类、腐蚀类型、腐蚀监测技术以及腐蚀防护技术进行了综合分析,探究铝合金在海洋环境中的腐蚀行为以及不同的防腐技术,为将来铝合金在深海或极端海洋工程领域的应用以及改善和提高铝合金防腐技术研究提供借鉴。

The heterogeneous impact of China-Europe railway express on the efficiency of logistics industry in node cities

Purpose-The spatiotemporal compression effect of China-Europe Railway Express(CR-Express)can reduce the filow costs of resources between China's node cities.Additionally,it can break through the limitations of low-added-value marine products,significantly impacting the logistics industry efficiency.However,there are few literature verifying and analyzing its heterogeneity.This study explores the impact of CR-Express on the efficiency of logistics industry in node cities and analyzes the heterogeneity.Design/methodology/approach-First,this study uses panel data to measure the efficiency of node city logistics industry.Secondiy,this study discusses the impact of the opening of CR-Express on the efficiency of logistics industry in node cities based on the multi-period differential model.Finally,according to the node city difference,the sample city experimental group is grouped for heterogeneity analysis.Findings-The results show that CR-Express can promote the urban logistics industry efficiency,with an average effect of 4.55%.According to the urban characteristics classification,the heterogeneity analysis shows that the efficiency improvement effect of logistics industry in inland cities is more obvious.The improvement effect of node cities and central cities in central and western China is stronger,especially in the sample of megacities and type I big cities.Compared with non-value chain industrial products,the CR-Express has significant promotion effects on the logistics efficiency of the cities where main goods are value chain products.Originality/value-Under the background of double cycle development,this paper can provide a scientific basis for the investment benefit evaluation of CR-Express construction and the follow-up route planning.

Risk assessment of high-speed railway CTC system based on improved game theory and cloud model

Purpose-In order to solve the problem of inaccurate calculation of index weights,subjectivity and uncertainty of index assessment in the risk assessment process,this study aims to propose a scientific and reasonable centralized traffic control(CTC)system risk assessment method.Design/methodologylapproach-First,system-theoretic process analysis(STPA)is used to conduct risk analysis on the CTC system and constructs risk assessment indexes based on this analysis.Then,to enhance the accuracy of weight calculation,the fuzzy analytical hierarchy process(FAHP),fuzzy decision-making trial and evaluation laboratory(FDEMATEL)and entropy weight method are employed to calculate the subjective weight,relative weight and objective weight of each index.These three types of weights are combined using game theory to obtain the combined weight for each index.To reduce subjectivity and uncertainty in the assessment process,the backward cloud generator method is utilized to obtain the numerical character(NC)of the cloud model for each index.The NCs of the indexes are then weighted to derive the comprehensive cloud for risk assessment of the CTC system.This cloud model is used to obtain the CTC system's comprehensive risk assessment.The model's similarity measurement method gauges the likeness between the comprehensive risk assessment cloud and the risk standard cloud.Finally,this process yields the risk assessment results for the CTC system.Findings-The cloud model can handle the subjectivity and fuzziness in the risk assessment process well.The cloud model-based risk assessment method was applied to the CTC system risk assessment of a railway group and achieved good results.Originality/value-This study provides a cloud model-based method for risk assessment of CTC systems,which accurately calculates the weight of risk indexes and uses cloud models to reduce uncertainty and subjectivity in the assessment,achieving effective risk assessment of CTC systems.It can provide a reference and theoretical basis for risk management of the CTC system.

Study on the pattern of train arrival headway time in high-speed railway

Purpose-The design goal for the tracking interval of high-speed railway trains in China is 3 min,but it is difficult to achieve,and it is widely believed that it is mainly limited by the tracking interval of train arrivals.If the train arrival tracking interval can be compressed,it will be beneficial for China's high-speed railway to achieve a 3-min train tracking interval.The goal of this article is to study how to compress the train arrival tracking interval.Design/methodologylapproach-By simulating the process of dense train groups arriving at the station and stopping,the headway between train arrivals at the station was calculated,and the pattern of train arrival headway was obtained,changing the traditional understanding that the train arrival headway is considered the main factor limiting the headway of trains.Findings-When the running speed of trains is high,the headway between trains is short,the length of the station approach throat area is considerable and frequent train arrivals at the station,the arrival headway for the first group or several groups of trains will exceed the headway,but the subsequent sets of trains will havea headway equal to the arrival headway.This convergence characteristic is obtained by appropriately increasing the running time.Originality/value-According to this pattern,there is no need to overly emphasize the impact of train arrival headway on the headway.This plays an important role in compressing train headway and improving high-speedrailwaycapacity.

Optimization study of station track utilization in high-speed railroad based on constraints of control in random origin and process

Purpose-The purpose of this paper is to eliminate the fluctuations in train arrival and departure times caused by skewed distributions in interval operation times.These fluctuations arise from random origin and process factors during interval operations and can accumulate over multiple intervals.The aim is to enhance the robustness of high-speed rail station arrival and departure track utilization schemes.Design/methodologylapproach-To achieve this objective,the paper simulates actual train operations,incorporating the fluctuations in interval operation times into the utilization of arrival and departure tracks at the station.The Monte Carlo simulation method is adopted to solve this problem.This approach transforms a nonlinear model,which includes constraints from probability distribution functions and is difficult to solve directly,into a linear programming model that is easier to handle.The method then linearly weights two objectives to optimize the solution.Findings-Through the application of Monte Carlo simulation,the study successfully converts the complex nonlinear model with probability distribution function constraints into a manageable linear programming model.By continuously adjusting the weighting coefficients of the linear objectives,the method is able to optimize the Pareto solution.Notably,this approach does not require extensive scene data to obtain a satisfactory Pareto solution set.Originality/value-The paper contributes to the field by introducing a novel method for optimizing high-speed rail station arrival and departure track utilization in the presence of fluctuations in interval operation times.The use of Monte Carlo simulation to transform the problem into a tractable linear programming model represents a significant advancement.Furthermore,the method's ability to produce satisfactory Pareto solutions without relying on extensive data sets adds to its practical value and applicability in real-world scenarios.

分“门”别类:博士生师门组织类型及其特征的质性研究

师门组织是博士生成长的主要微观环境。师门通常由导师领导和管理,承载着师生、学生之间的学术交流、情感互动等,是区别于院系、研究所等正式组织进行博士生培养的非正式组织。运用质性研究方法,通过对“双一流”高校不同学科的博士生进行深度访谈发现:博士生师门存在理性密集型、理性松散型、自然密集型、自然松散型四种类型;各类师门组织在组织管理方式、组织结构、人员密度、组织氛围、培养成效方面存在差异。相较之下,密集型师门组织比松散型更有利于博士生及时获得指导与支持,师门组织管理过于正式或非正式都不利于博士生成长。良好的师门组织建设只有充分发挥导师的主导作用,注重学科差异和文化建设,才能打造有利于导生共同发展、相互成就的学术共同体。

科研人员探索式搜索任务类型与特征研究

[目的/意义]随着科技创新进程的加速与深入,科研人员的知识需求逐渐呈现出深度化、模糊化等特征,其知识搜索也大多表现为一种探索性的搜索过程。研究科研人员探索式搜索任务类型与特征有利于细粒度揭示科研人员信息需求特征,为科技信息服务平台的精准化知识服务提供理论依据,从而促进科技知识共享,加快科技创新进程。[方法/过程]以集成电路领域为例,文章采用关键事件技术法和在线问卷调查法进行数据收集,同时基于多重信息搜寻时段模型进行内容分析和编码,并进行数据统计分析。[结果/结论]集成电路领域探索式搜索包括两种任务类型(学习型和研究型)及其13种任务子类型,其中,来源、搜索频率、知识储备需要、复杂度的知识维度和认知维度5个任务属性与任务子类型显著相关,同时各任务属性间的共现结果体现了最常见的任务属性组合。本研究将为更好地理解科研人员的领域知识需求,以及开展后续的科研人员信息搜索行为研究和搜索系统优化提供一定参考。

带存储的系统的可靠性研究综述

系统可靠性是度量各个系统服务质量的重要指标之一,其可靠性得到越来越多的学者关注。首先总结了带存储的系统在排队系统、制造系统、生产系统、生产库存系统、能源存储系统等不同研究类型中的研究热点;然后利用Citespace软件对不同研究类型中的关键词进行分析,得出目前关键词主要的聚类单元为预防性维护、负荷波动率、任务成功概率等;最后根据目前的研究情况说明了现有研究的主要问题,并给出了研究展望。

美国人工智能研究院研发组织和运营模式研究

2020年以来,美国政府组建系列国家人工智能研究院,其研发组织与运营模式代表了未来新型研发组织的发展方向。研究定位上,面向研究时间长、前沿交叉学科且需多机构合作完成的人工智能领域;组织和运营模式上,从组织架构、支持资金、成果转化和决策模式4个方面进行了创新。中国人工智能新型研发机构在实际运行中仍然存在不足,应充分发挥政府统筹协调作用;支持建立开放协作的产业生态,研发与应用端融合,加快迭代速度;帮助企业培育初期市场,减少企业创新的市场不确定性。

惯质黏性阻尼器对悬索桥隧道锚减振的影响

为研究隧道锚(tunnel-type anchor,简称TTA)锚岩接触面对动荷载影响的敏感性,寻求一种适用于散索鞍至锚碇缆索处的减振装置。首先,利用有限差分软件建立隧道锚数值模型,监测并分析锚岩接触面共9个测点的速度位移响应;其次,利用滚珠丝杠构件的位移转换放大原理,提出一种适用于前锚室处的惯质黏性阻尼器;最后,利用能量耗散守恒方法,模拟并检验安装该阻尼器后隧道锚的减振效果。结果表明:在动荷载作用下,锚塞体两底角部位测点响应明显大于顶部测点,中部锚岩接触面位移增长较前部与后部更为迅速;隧道锚受低幅值动荷载影响更为明显,动力系数约为1.3,随着荷载幅值的增加,动荷载对于隧道锚的影响会减弱;振动前期较为剧烈,加载0~1 s内剪应变增量增幅明显,后期增量基本不变;设置阻尼器后,锚岩接触面速度位移响应减小,位移减小幅度接近20%,速度响应在1 s内基本衰减至0;阻尼器的减振效果与荷载幅值有关,锚塞体处于中低载荷时,设置阻尼器所带来的减振效果最好,减小效果可以达到24%。

输电塔斜材不同节点型式下的受压承载力

为研究节点约束下输电塔斜材受压承载力的计算方法,通过对120根等边角钢的偏心受压承载力试验,分析其最小轴、平行轴布置时的破坏模式、承载力及变形形态,研究不同约束刚度、节点型式对其承载力的影响;结合现行行标公式,针对不同节点连接型式(A、B、C类),提出输电塔斜材受压长细比的计算公式.研究结果表明:长细比小于120时,构件承载力主要受偏心控制,偏心越大,承载力越低;而长细比大于120时,构件承载力主要受约束刚度控制,约束刚度越大,承载力越高;A、C类连接在不同长细比时各具优势,但B类连接的承载力始终低于A、C类连接;国内外规范计算值与试验值均存在较大的偏差,具有一定的局限性,体现在小长细比构件偏心及大长细比构件约束修正不足等方面;所提出长细比修正公式的计算结果与试验结果吻合良好,可用于指导工程设计.

高效多刀位推进式全自动坚果取仁装置应用研究

坚果取仁是坚果加工过程中一道重要工序,取仁装置是该工序的主要设备。传统取仁装置分为人工取仁和人工协同取仁装置取仁,存在费时费力、自动化程度低、进料不均、效率低、质量差、易堵塞、不防滑等缺点。根据坚果取仁工艺存在的问题,研制出了多刀位推进式全自动坚果取仁装置,具有进料均匀、全自动、取仁效率高、取仁质量好、省时省力、不易堵塞和打滑等优点,经济效益和社会效益较好,有显著的推广应用前景。

地浸砂岩型铀矿松散岩层单动双管取心钻具的研制与试验

为解决单管钻具取心工艺方法在深部目的层/矿层等松散岩层取心中存在的取心质量差、取心效率低和操作难度大的问题,开展了地浸砂岩型铀矿松散岩层单动双管钻具的研制和试验。通过设计和改进单动机构、断心结构、液力退心机构和快拆机构,研制了两类分别具有可直接液力退心和快速拆卸功能的SD型单动双管钻具。试验结果表明:SD110型双管钻具可在免拆内管的情况下实现地表快速液力退心,提高双管钻具退心效率;SDKC110型钻具可快速拆装更换内管,实现退心和钻进平行作业。与单管钻具相比,SD系列单动双管钻具在松散岩层的平均回次长度提高28.62%,平均机械钻速提高11.61%;与常规单动双管钻具相比,退心操作时间降低了32.69%。SD系列单动双管钻具适用于在松散破碎地层进行取心钻进应用,可有效提高岩心采取效率和岩心质量。

基于新型泳池式研究堆BNCT中子束流装置方案设计研究

本研究基于新型泳池式研究堆设计方案,开展了硼中子俘获治疗(BNCT)能谱可变中子束流装置的初步方案设计。根据新型泳池堆堆芯结构,采用屏蔽体及准直器组合方式,对BNCT的中子慢化层、热中子吸收层、伽马屏蔽层以及中子准直器进行了分析计算及优化,在不增加中子引出束流孔道数量的前提下,实现了超热中子及热中子BNCT束流的切换,通过理论计算分析确定了两种装置的中子束流特性,超热/热中子通量密度、单位快中子剂量、单位光子剂量、热中子通量占比等参数均符合IAEA-TECDOC-1223报告的BNCT推荐参考标准,可用于不同能量需求的硼中子俘获治疗,为新型多功能泳池堆的应用及推广提供了技术支持。

月球科研站基本型能源系统方案设计与关键技术研究

调研了国内外无线传能技术和燃料电池技术的研究现状,在探月四期工程的整体规划框架下,对月球科研站基本型能源系统任务需求进行分析研究;提出了月球科研站基本型的能源系统组成,对能源系统的功能、工作原理和工作模式进行分析,给出了主要技术指标;对能源系统涉及到的关键技术进行初步分析,包括热电一体化能源综合利用技术、可再生燃料电池高可靠及高效控制技术、小型化高效远场激光无线传能技术、千瓦级近场无线传能技术和复杂多源能源系统稳定性建模与分析技术;基于方案设计和关键技术分析,对后续工作进行探讨,给出了下一步工作建议。

论涉网新型诈骗犯罪治理下的情报研判

当前,犯罪分子使用了大量的诈骗技术手段,使得涉网新型诈骗犯罪手法不断翻新,传统骗术没落,刷单、虚假交易诈骗突出。诈骗手法紧蹭社会热点,新型骗术层出不穷,“局中局”“骗中骗”,复合式刷单陷阱横行。但公安机关情报研判部门存在情报精准研判水平较低、情报研判制度不完善,情报互通困难等问题,情报研判队伍的水平有待整体提高。基于此,树立以情报研判为中心的观念,组建高水平情报研判人才队伍,加强与各部门之间的联系,健全完善情报研判流程是当前迫切之需。未来,公安机关应转变思路,重视运用大数据技术,以研判为核心推进侦查信息化发展,加强资源集成,努力达成数据资源的整合应用。

育肾养卵方治疗肾虚型高龄卵巢储备功能减退的临床研究

目的观察育肾养卵方治疗肾虚型高龄卵巢储备功能减退的临床疗效。方法将90例肾虚型高龄卵巢储备功能减退患者,按照随机数字表法分为治疗组和安慰剂组,每组45例。治疗组予口服育肾养卵方,安慰剂组予口服安慰剂,连续治疗3个月经周期。观察2组患者血清基础性激素(FSH、LH、E2、FSH/LH)、抗缪勒管激素(AMH)、窦卵泡计数(AFC)、中医证候积分、卵巢动脉血流的变化和安全性指标。结果治疗后2组间比较,治疗组血清FSH、LH、FSH/LH水平明显低于安慰剂组(P<0.05),血清E2、AMH水平高于安慰剂组(P<0.05);治疗组窦卵泡数明显高于安慰剂组(P<0.05);治疗组中医证候积分明显低于安慰剂组(P<0.05);治疗组PI、RI明显低于安慰剂组(P<0.05),PSV高于安慰剂组(P<0.05)。结论育肾养卵方治疗肾虚型高龄卵巢储备功能减退,临床疗效显著,可以有效改善患者的临床症状,增加窦卵泡数量,其作用机制可能与调节基础性激素水平,改善卵巢动脉血供有关。