放电等离子烧结纳米复合Ti(C,N)基金属陶瓷

采用放电等离子技术（SPS）烧结制备出纳米复合Ti（C，N）基金属陶瓷材料。用光学显微镜、扫描电镜和能谱仪等对烧结体的孔隙率、微观组织和断口形貌等进行了观察，并对不同条件下材料的力学性能进行了对比分析。结果表明：直接升温到1250℃保温8min可获得较好的力学性能；在显微结构中，除了黑芯／白环的结构外，还存在着白芯／黑环结构；孔洞和大颗粒硬质相为主要的断裂源，断裂方式以沿晶断裂为主，同时存在着解理断裂和穿晶断裂。     

碳纳米管预处理及其对Ti(C,N)基金属陶瓷性能的影响

利用化学沉积方法对表面改性后的碳纳米管进行进行镍包覆,在Ti(C,N)基金属陶瓷中添加不同含量的碳纳米管作为增强相,采用粉末冶金法制备了碳纳米管增强的Ti(C,N)基金属陶瓷材料;研究了碳纳米管的表面改性、加入量及烧结温度对金属陶瓷性能的影响。结果表明:当pH值为4.5时得到的镍镀层比pH值为9时得到的镍镀层连续光滑;当碳纳米管含量由0增加到0.5%(质量分数)时,Ti(C,N)基金属陶瓷的抗弯强度随碳纳米管含量的增加而升高,1 420℃烧结时,其抗弯强度最大。     

双重润滑条件下的刀具切削特性研究

为实现清洁切削技术,将Al2 O3包覆CaF2复合粉体作为添加相,采用真空热压烧结工艺制备了一种Ti(C,N)基自润滑金属陶瓷刀具(TMC刀具),研究了Ti(C,N)基金属陶瓷刀具在微量润滑作用下切削300M钢的切削性能,结果表明:双重润滑与干切削方式相比,其三向切削力FX、FY、FZ分别减小了36.8％、13.1％和...     

AlN含量对Ti(C,N)基金属陶瓷组织和性能的影响

研究了AlN添加量(0,1%,2%,3%,质量分数)对Ti(C,N)基金属陶瓷硬度、抗弯强度以及抗氧化性能的影响。结果表明:不同AlN添加量下的金属陶瓷主要由Ti(C,N)、Ni3Al和镍相组成;随着AlN添加量增加,金属陶瓷的硬度增大,抗弯强度先增大后减小,AlN添加量为2%时达到峰值;与未添加AlN相比,添加2%AlN金属陶瓷的氧化质量增加较慢,氧化膜结构更致密,抗氧化性能更好。     

氮化碳基陶瓷刀具材料的制备与力学性能研究

采用热压烧结工艺,以Ti(C, N)为添加相,以Mo、Ni和Co为金属相,成功制备了氮化碳(C₃N₄)基陶瓷刀具材料,测量了其断裂韧度、抗弯强度和维氏硬度,分析了其微观组织。结果表明,在烧结温度为1600℃、保温时间为45 min和烧结压力为32 MPa的工艺条件下,Ti(C, N)质量分数为35%、Ni-Co质量分数为8%的C₃N₄基陶瓷刀具材料力学性能最优。合适的Ti(C, N)含量能细化C₃N₄晶粒、提高烧结密度、改善力学性能,合适的Ni-Co含量能使微观组织细小均匀。     

Ti(C,N )基金属陶瓷粉末注射成形技术研究概述

概述了Ti(C，N)基金属陶瓷粉末注射成形的粉末特性、粘结剂体系、喂料制备、注射成形、脱脂技术、烧结与致密化；分析表明：粉末注射成形技术在制备复杂几何形状、均匀组织结构和高性能高精度近净成形Ti(C，N)基金属陶瓷材料产品方面具有独特的技术优势和发展潜力。     

Ti(C,N)基金属陶瓷刀具与纳米改性

介绍了Ti(C,N)基金属陶瓷刀具材料的特点及适用范围，分析了如何用纳米技术对Ti(C,N)基金属陶瓷刀具材料进行改性，以提高其强韧性，同时简述了其制备的工艺过程，进行了切削试验，并指出其合适的加工材料。     

WC和Mo_2C的添加对Ti(C,N)基金属陶瓷高温显微硬度的影响

基于WC与Mo_2C对Ti(C,N)基金属陶瓷的组织优化和润湿性改善等方面具有相似的作用,研究了WC和Mo_2C的添加对Ti(C,N)基金属陶瓷在高温下显微硬度的影响。结果表明:随着温度的升高,添加WC和Mo_2C后金属陶瓷的高温显微硬度均呈下降趋势,在600~800℃范围内,添加WC后金属陶瓷的高温显微硬度略高于添加Mo_2C金属陶瓷的,当温度达到900℃时,两者的显微硬度几乎相同;随着温度的升高,两种金属陶瓷的压痕面积、平均压痕深度均逐渐增加;添加WC后金属陶瓷的高温真应变明显小于添加Mo_2C金属陶瓷的,但当温度达到900℃时,两种金属陶瓷的高温变形量接近。     

不同升温速率和烧结气氛对金属陶瓷刀片车削性能的影响

将Ti(C,N)基金属陶瓷在1350℃以上以不同的升温速率和烧结气氛工艺进行烧结，采用SEM、XRD等分析研究了合金性能的影响，并进行了45钢的车削性能测试。结果表明：不同烧结工艺可以获得不同的合金性能和外观形态，慢速烧结促进烧结过程的固溶程度，真空条件可以促进(200)择优，在连续切削45钢时具有更优异的耐磨性能。     

VC对微米级Ti(CN)基金属陶瓷微观结构和力学性能的影响

VC对于制备微米级的Ti(CN)基金属陶瓷,能够起到控制Ti(CN)晶粒长大的作用,并且能够使烧结体中晶粒粒度分布变得均匀。在液相烧结过程中,由于瓦尔德熟化效应使Ti(CN)晶粒长大,Ti(CN)晶粒的长大又分为连续长大和不连续长大。关于VC的抑制机理,目前还没有明确的结论,但有三种比较有代表性的说法:吸附机制、溶解机制和偏析机制。随着VC添加量的增加,Ti(CN)基金属陶瓷的抗弯强度呈现先升后降的趋势;VC的加入使材料的硬度减小。     

飞行时间质谱仪射频四极杆驱动器的研制

针对自制垂直引入式飞行时间质谱仪（orthogonal extraction time-of-flight mass spectrometer, O-TOFMS）的需要,运用直接数字频率合成 (direct digital frequency synthesis,DDS)技术,研制了射频四极杆的高压射频驱动电路装置。该驱动器频率可调范围为0.5~2 MHz,幅度最高达到1 000 Vp-p。该射频四极杆驱动器（radio frequency quadrupole driver,RFQ Driver）可用于分子离子反应器（molecule ion reactor,MIR）和RFQ驱动,其结构简洁、成本低、性能稳定可靠。     

Rapid one-of-a-kind production

To shorten the product development cycle time and reduce the cost at the same time, which is very critical for the survival of those small and mid-sized one-of-a-kind production (SMOKP) companies, various computer communication, simulation and computer aided engineering and management techniques have been widely used in these SMOKP companies. However, according to our study, the applications of these advanced computer technologies in these SMOKP companies are lack of system integration and synergy, which result in communication errors, reworks, duplications and hence a longer product development lead time and a higher cost. To solve this problem, an inter/intranet based computer aided rapid product development system is presented in this paper. This system consists of a number of inter/intranet based computer models or sub-systems for supporting rapid development of a one-of-a-kind product. It also employs a novel concurrent product development strategy called “prototype based incremental product development strategy” and an integrated product data structure called “product production structure”. Some industrial implementations of the proposed system, product development strategy and product data structure are also reported in the paper.     

Rapid one-of-a-kind production

To shorten the product development cycle time and reduce the cost at the same time, which is very critical for the survival of those small and mid-sized one-of-a-kind production (SMOKP) companies, various computer communication, simulation and computer aided engineering and management techniques have been widely used in these SMOKP companies. However, according to our study, the applications of these advanced computer technologies in these SMOKP companies are lack of system integration and synergy, which result in communication errors, reworks, duplications and hence a longer product development lead time and a higher cost. To solve this problem, an inter/intranet based computer aided rapid product development system is presented in this paper. This system consists of a number of inter/intranet based computer models or subsystems for supporting rapid development of a one-of-a-kind product. It also employs a novel concurrent product development strategy called “prototype based incremental product development strategy” and an integrated product data structure called “product production structure”. Some industrial implementations of the proposed system, product development strategy and product data structure are also reported in the paper.     

简介虚拟制造中的网络虚拟现实技术

介绍了网络虚拟现实建模语言（VRML），VRML具有动态对象描述和超链接、通用性、扩展性、易实现性等特点。VRML浏览器和生成VRML文件的工具广泛使用于多种平台的计算机，是虚拟制造VM与虚拟设计中的网络虚拟现实技术的基础。     

从光电容积图中提取脉搏率、呼吸率和心率的新方法

光电容积描记图(PPG)是一种利用光学技术无创检测人体心血管脉搏波的方法。PPG信号来源于MIMIC数据库,它含有许多生理信息。本文提出了将集合经验模态分解(EEMD)、倒谱、快速傅里叶变化和过零点检测相结合的方法,从PPG中可靠地估算脉搏率(PR)、心率(HR)和呼吸频率(RR)。首先,将PPG信号通过EEMD分解为有限个固有模态函数(IMF)。因为EEMD有自适应滤波特性,所以估算不同的生理参数时,可以用不同的IMF分量来重构信号。其次,估算脉搏率时,舍去低频含有伪迹的IMF,再通过过零点检测可以得到瞬时脉搏率。然后,估算心率时,用1 Hz~1.67 Hz(60次/分钟~100次/分钟)的IMF来重构信号,再求倒谱,选取反映心脏活动的频带来得到心率。最后,估算呼吸率时,用0.05 Hz~0.75 Hz(3次/分钟~45次/分钟)的IMF来重构信号,然后对呼吸信号求快速傅里叶变化得到频谱图,寻找频谱图中的峰值得到呼吸率。对来自MIMIC数据库的53个成人PPG信号进行了仿真。仿真结果表明使用该综合信号处理方法提取的生理参数与实际生理参数一致,且该方法有运算量小,精确度高的优点(误差不超过1.17%)。     

UPLC-MS/MS测定二苯甲烷二异氰酸酯

建立了二苯甲烷二异氰酸酯（MDI）的超高效液相色谱-串联质谱（UPLC-MS/MS）联用的分析方法。实验用甲醇作衍生试剂,将二苯甲烷二异氰酸酯衍生成二苯甲烷二氨基甲酸甲酯（MDC）,通过测定二苯甲烷二氨基甲酸甲酯来确定二苯甲烷二异氰酸酯的含量。实验采用Waters Acquity BEH C18超高效液相色谱柱,甲醇-0.1%甲酸作为梯度洗脱液,二苯甲烷二氨基甲酸甲酯在1.5 min内与其他化合物进行完全分离,经四极杆质谱选择离子监测模式检测。线性范围为2~100 μg/L,检出限为1 μg/L,相关系数0.999 4。考察了水、甲酸、甲酸铵流动相体系,以及进样量大小对样品的分离效果,发现甲酸流动相体系的分离效果优于其他两种流动相体系,同时发现在进样量大时出现平头峰。并且在优化条件下,对实际样品中游离的二苯甲烷二异氰酸酯进行了测定。     

血清AFP、CA199、GGT、ALP联检肝癌早期诊断价值

目的:探讨甲胎蛋白(AFP)、糖类抗原199(CA199)、谷氨酰转肽酶(GGT)和碱性磷酸酶(ALP)单独或联合检测对原发性肝癌(PHC)的早期诊断价值。方法:本研究为回顾性研究,筛选2016年-2019年本院87例原发性肝癌(PHC)患者、105例慢性乙肝患者及104例健康志愿者,收集不同组首次入院和体检外周血检测数据和其他临床资料。比较各血清指标在组间差异性,分析了血清学指标与入组PHC临床分期和病理分型的相关性,进一步利用ROC曲线法分析血清指标单项与联合诊断的灵敏度、特异度。结果:AFP、CA199、GGT、ALP检测均值在PHC组均明显高于慢乙肝组和健康体检组。AFP阳性检测值与PHC临床分期(r=0.9536)和病理分型(r=0.525)呈正相关性。AFP诊断PHC灵敏度和特异性分别为60.87%和77.97%、精准度AUC为0.726。联合四项指标检测灵敏度、特异度和AUC分别为75.36%、65.64%、0.806。结论:AFP、CA199、GGT、ALP四项指标联合检测可提高原发性肝癌早期诊断的准确率,操作性强且易于推广。     

Effect on crystalline structure of AISI M2 steel using tungsten–thorium electrode through MRR,EWR, and surface finish

To investigate on the crystalline structure of AISI M2 steel by using tungsten–thorium electrode in electrical discharge machining (EDM) process was studied. Furthermore, the investigation were carried out for finding the value of material removal rate (MRR), electrode wear rate (EWR) and surface roughness (SR) of tool steel material depending upon three variable input process parameters. On the basis of weight loss, the value of MRR and EWR were calculated at optimized process parameter. Subsequently, surface topography of the processed material were examined through different characterization techniques like scanning electron microscopy (SEM), Optical surface profiler (OSP) and Atomic force microscopy (AFM), respectively. In XRD study, broadening of the peak was observed which confirmed the change in material properties due to the homogeneous dispersion of the particles inside the matrix. Lowest surface roughness and MRR of 0.001208 mg/min was obtained. Minimum surface roughness was obtained 1.12 μm and 2.18427 nm by OSP and AFM study, respectively. Also, minimum EWR was found as 0.013986 mg/min.     

A novel virtual instrument for power quality surveillance based in higher-order statistics and case-based reasoning

This paper presents the performance results of a Virtual Instrument (VI) based in Case-Based Reasoning (CBR), conceived to online monitor the power-quality. The PC-based instrument receives data through a DAQ board and a differential probe, while maintaining economy by eliminating the extra network construction and hardware. Being flexible, presents an user-friendly interface and a large data storage capacity, since it uses the hard disk. The computational guts of the instrument are based in third and fourth-order statistics (along with the variance), which enhance detection capability and reject noise influence. A time-domain sliding window sweeps the register under test and offers a time-variation pattern which reflects the deviation of the statistical estimator with respect to the steady state. This three-valued time-series comprises variance, skewness and kurtosis evolution, and constitutes a triple input to the innovative CBR module, which in turn is capable of distinguishing electrical anomalies among five categories (the sixth is reserved to the healthy signal): non-50 Hz, 50-Hz-asymmetrical, 50-symmetrical non-sinusoidal, swell and sag. Online surveillance tests developed over the local electrical network show acceptable accuracy (96%).