Formation mechanism of bainitic ferrite and carbide

Superledges on the broad faces of bainitic ferrite plates have been observed with transmission electron microscope (TEM). The observed superledges, ranging from less than 1 to 24 nm in height, are imaged in three dimension by way of tilt operation under TEM. Also, an array of smaller superledges are observed to pile up in front of a secondary phase. Pileup of superledges in front of a barrier is indicative of the mobility of an individual superledge. The precipitation of carbide associated with bainitic ferrite is also studied. It is observed that a carbide of a wedgelike shape may exist in front of a superledge with its tip(i.e., thinner end) penetrating the austenite and its root (the other end) originating at α:γ boundary. This condition indicates that the observed carbides may nucleate at the austenite side of α:γ phase boundary and grow toward austenite matrix. This article is based on a presentation made at the Pacific Rim Conference on the “Roles of Shear and Diffusion in the Formation of Plate-Shaped Transformation Products,” held December 18-22, 1992, in Kona, Hawaii, under the auspices of ASM INTERNATIONAL’S Phase Transformations Committee.     

Simulation studies of inverted pendulum based on PID controllers

The inverted pendulum problem is one of the most important problems in control theory and has been studied excessively in control literatures. When a control system have more than two PID controllers, the adjustment of PID parameters is not an easy problem. In this paper, PID controllers are applied to the stabilization and tracking control of three types of inverted pendulum. The way how to design the PID controllers is given step by step in this paper. Simulation results prove that the way to design of PID controllers is very simple and effective. The system design not only can realize stabilization and tracking control of three types of inverted pendulum, but also have robustness to outer large and fast disturbances.     

A local experts organization model with application to face emotion recognition

This paper presents a novel approach for recognizing human facial emotion in order to further detect human suspicious behaviors. Instead of relying on relative poor representation of facial features in a flat vector form, the approach utilizes a format of tree structures with Gabor feature representations to present a facial emotional state. The novel local experts organization (LEO) model is proposed for the processing of this tree structure representation. The motivation for the LEO model is to deal with the inconsistent length of features in case there are some features failed to be detected. The proposed LEO model is inspired by the natural hierarchical model presented in natural organization, where workers (local experts) reports to their supervisor (fusion classifier), whom in turn reports to upper management (global fusion classifier). Moreover, an Asian emotion database is created. The database contains high-resolution images of 153 Asian subjects in six basic pseudo-emotions (excluding neutral expression) in three different poses for evaluating our proposed system. Empirical studies were conducted to benchmark our approach with other well-known classifiers applying to the system, and the results showed that our approach is the most robust, and less affected by noise from feature locators for the face emotion recognition system.     

负载缺位钨硅酸的有机无机复合光致变色薄膜

采用sol-gel技术, 利用缺位杂多酸中氧原子不饱和性, 将Keggin结构缺位杂多酸盐SiW₁₁以共 价键结合到SiO₂ 网络上, 制备了SiW₁₁/SiO₂/PVA复合薄膜. IR光谱表明, SiW₁₁在基体中基本保持Keggin结构, 与SiO₂网络上形成了W--O--Si 共价键. 由于W--O--Si键的生成, 造成Keggin结构SiW₁₁产生一定的形变. 此薄膜在紫外光照射下变蓝, 具有较好的光致变色性质.     

涡轮流量计故障分析与处理

在科威特27#集油站投产保运期间,外输轻质油流量计投用时发现差压流量计指示正常,而FC50系列涡轮流量计无指示,轻质油外输工艺流程如图1。FC50系列涡轮流量计为轻质油外输累积计量流量计,业主十分关注,需尽快解决。经自己认真检查、分析、处理,使问题得到了圆满解决,为公司赢得了荣誉。     

Pb(Mg1/3Nb2/3)O3-0.3PbTiO3单晶紫外可见近红外光学性质

通过温度依赖的透射和反射光谱研究了在准同型相界附近的Pb(Mg_(1/3)Nb_(2/3))O_3-0.3PbTiO_3(PMN-0.3PT)单晶光学性质.这种禁带宽度随温度范围不同变化规律不同现象,揭示了PMN-PT单晶温度依赖的复杂相结构.禁带宽度Eg在303 K是3.25 e V,临界点Ea是3.93 e V,临界点Eb是4.65 e V,它们随着温度的上升而下降,在453 K禁带宽度Eg是3.05 eV,临界点Ea是3.57 eV,临界点Eb是4.56 eV.这三个跃迁能量Eg、Ea、Eb分别对应从O 2p到Ti d、Ni d、Pb 6p轨道跃迁.它们随温度上升而下降的变化规律可以用晶格热膨胀和电子声子相互作用理论来解释.通过Tauc-Lorentz色散模型拟合得到了303 K到453 K温度范围的Pb(Mg_(1/3)Nb_(2/3))O3-0.3PbTiO_3单晶光学常数及其随温度的变化规律,发现折射率n随着温度的升高而升高.     

The phase structure and electric properties of low-temperature sintered (K,Na)NbO3-based piezoceramics modified by CuO

0.25 wt% CuO-doped (Li,K,Na)(Nb,Ta)O₃–AgSbO₃ lead-free piezoceramics with pure perovskite structure were successfully prepared at a sintering temperature below 1000 °C. The sintering temperature of KNN-based piezoceramics was effectively reduced by about 100 °C due to the enhanced densification process induced by the addition of CuO. Besides, the acceptable sintering temperature window was broadened by the addition of CuO. It is found that the CuO-doped samples show slightly higher tetragonal–orthorhombic phase transition point (T_T−O) but a lower Curie point (T_c), compared to undoped ones. The KNN-based piezoceramics became “hard” as CuO was added, supported by an increase of Q_m. Fairly good electrical properties of d₃₃^*=383 pm/V, ε_r=860, Q_m=188 and T_c=215 °C could be obtained in dense CuO-modified KNN-based piezoceramics sintered at 970 °C, demonstrating promising potential in practical applications.     

Prediction of the fretting fatigue resistance of various surface-modification layers on 1045 steel: the role of fretting maps

In this work, fretting maps of various surface modifications were established based on the friction logs of fretting experiments. The fretting fatigue resistance of the coatings was analyzed according to the features of the fretting maps of the coatings. The results showed clearly that fretting maps of materials are effective tools to predict the fretting fatigue properties of substrates and surface-modification coatings. It was also demonstrated that the fretting fatigue resistance of a 1045 steel substrate could be improved to different extents through surface modification. The fretting fatigue resistance of solid lubricating coatings was the best and the tendency for initiation and propagation of cracks in the substrate material could also be restrained by depositing hard coatings.