基于LMI的旋转起重机鲁棒控制器设计

悬绳和荷载组成的振动系统的固有频率变化会对控制系统的稳定性和控制性能产生影响,因此针对此问题提出一种低复杂度的鲁棒控制器设计方法。首先,采用干扰观测器导出起重机的线性模型。该模型对于关节摩擦,荷载质量以及旋转速度等参数变化具有鲁棒性。其次,基于该线性模型设计一个含有积分器的状态反馈控制器,其增益通过线性矩阵不等式(LMI)优化算法求出,并且该控制器对于绳长变化具有鲁棒性。最后,比较仿真和实验结果验证所提方法的有效性。通过使用此法可以实现在无测量绳长的传感器系统的情况下容易地操作起重机,从而大大地简化其结构和降低其安装成本。     

Catalytic activity of titanium oxide for oxygen reduction reaction as a non-platinum catalyst for PEFC

A non-platinum cathode electrocatalyst must have the stability and catalytic activity for the oxygen reduction reaction (ORR) in order to be used in polymer electrolyte fuel cells (PEFCs). Titanium oxide catalysts as the non-platinum catalyst were prepared by the heat treatment of titanium sheets in the temperature range from 600 to 1000 °C. The prepared catalysts were chemically and electrochemically stable in 0.1 mol dm⁻³ H₂SO₄. The titanium oxide catalysts showed different catalytic activities for the ORR. The ORR of the catalysts heat-treated at around 900 °C occurred at the potential of about 0.65 V versus RHE. It is considered that the deference in the catalytic activity for the ORR of the heat-treated titanium oxide catalysts was due to the fact that the heat-treatment condition changed the material property of the catalyst surface. In particular, it was found that the catalytic activity for the ORR of the Ti oxide catalysts increased with the increase in the specific crystalline structure, such as the TiO₂ (rutile) (1 1 0) plane and the work function. It is considered that a surface state change, such as the crystalline structure and work function, might affect the catalytic activity for the ORR.     

Rare Hereditary Gynecological Cancer Syndromes

Hereditary cancer syndromes, which are characterized by onset at an early age and an increased risk of developing certain tumors, are caused by germline pathogenic variants in tumor suppressor genes and are mostly inherited in an autosomal dominant manner. Therefore, hereditary cancer syndromes have been used as powerful models to identify and characterize susceptibility genes associated with cancer. Furthermore, clarification of the association between genotypes and phenotypes in one disease has provided insights into the etiology of other seemingly different diseases. Molecular genetic discoveries from the study of hereditary cancer syndrome have not only changed the methods of diagnosis and management, but have also shed light on the molecular regulatory pathways that are important in the development and treatment of sporadic tumors. The main cancer susceptibility syndromes that involve gynecologic cancers include hereditary breast and ovarian cancer syndrome as well as Lynch syndrome. However, in addition to these two hereditary cancer syndromes, there are several other hereditary syndromes associated with gynecologic cancers. In the present review, we provide an overview of the clinical features, and discuss the molecular genetics, of four rare hereditary gynecological cancer syndromes; Cowden syndrome, Peutz-Jeghers syndrome, DICER1 syndrome and rhabdoid tumor predisposition syndrome 2.     

Activity of oxygen reduction reaction on small amount of amorphous CeOx promoted Pt cathode for fuel cell application

Pt on ceria (CeO_x) particles supported on carbon black (CB) were synthesized using the combined process of hot precipitation and impregnation methods. During 30 cycles of cyclic voltammetry pre-treatment in the potential ranging from −0.2 to 1.3 V (V vs. Ag/AgCl), it was observed that a small amount of CeO_x, which consisted of the interface region between Pt and CeO_x, remained on Pt particles. Other free CeO_x particles were dissolved into H₂SO₄ aqueous solution. To develop the Pt-CeO_x/CB catalyst, the surface chemical states, the net chemical composition, morphology and electrochemical behavior in H₂SO₄ aqueous solution were characterized. Our microanalysis and electrochemical analysis indicate that the active CeO₂ with high specific surface area provides the continuous amorphous cerium oxide (Ce³⁺, Ce⁴⁺) layer with pores on the surface of Pt particles. It is concluded that the amorphous cerium oxide layer on Pt inhibits the oxidation of Pt surface and contributes to enhancement of the activity on Pt cathode. The single cell performance was also improved using the Pt-CeO_x/CB cathode. Based on all data, it is expected that the design based on characterization of the interface between Pt and small amount of amorphous cerium oxide layer could help in preparation of more active Pt catalyst.     

Effective thermal conductivity of MOX raw powder

The radial temperature distribution of plutonium and uranium mixed oxide powder loaded into a cylindrical vessel was measured in air and argon gas, and the effective thermal conductivity was calculated from the measured temperature distribution and the decay heat. The effective thermal conductivities were small values of 0.061-0.13 W m^-1 K^-1 at about 318 K, and changed significantly with O/M, bulk density and atmospheric gas. The results in this work were analyzed by the model of Hamilton and Crosser and a new model for the effective thermal conductivity of the powder was derived as functions of powder properties and thermal conductivity of atmospheric gas.     

Oxygen chemical diffusion in hypo-stoichiometric MOX

Kinetics of the oxygen-to-metal ratio change in (U_0.8Pu_0.2)O_2−x and (U_0.7Pu_0.3)O_2−x was evaluated in the temperature range of 1523-1623 K using a thermo-gravimetric technique. The oxygen chemical diffusion coefficients were decided as a function of temperature from the kinetics of the reduction process under a hypo-stoichiometric composition. The diffusion coefficient of (U_0.7Pu_0.3)O_2−x was smaller than that of (U_0.8Pu_0.2)O_2−x. No strong dependence was observed for the diffusion coefficient on the O/M variation of samples.     

Development of group 4 and 5 metal oxide-based cathodes for polymer electrolyte fuel cell

Partially oxidized zirconium, niobium, and tantalum carbonitrides were prepared to discuss a characteristic common to all. The onset potential for the ORR of partially oxidized carbonitrides reached above ca. 0.85 V. The XRD and XPS analyses suggested that both the crystalline structure and the chemical bonding state of the surface of the partially oxidized carbonitrides were very similar to those of the oxides. However, the partially oxidized carbonitrides had lower ionization potential than the oxides. The lower ionization potential indicated that the partially oxidized carbonitrides had some defects on the surface. From these results, the structure of oxides and the highest oxidation state of surface metal with some oxygen defects were essential to have high ORR activity for group 4 and 5 oxide-based compounds. Such oxygen defects might be responsible for the oxygen reduction capability by creating electronically favorable oxygen adsorption sites.     

Fuzzy servo control of an inverted pendulum system

In this paper, an application of fuzzy servo control for stabilizing inverted pendulum system will be discussed. The inverted pendulum system is a simple system that consists of pendulum and cart but has strong nonlinearity and inherent instability. It is used as benchmark problem for study the performance and effectiveness of new control method. The idea behind this control method is to divide the operating region of nonlinear system into small areas, and to treat as a collection of local linear servo systems by using Davison?CSmith method. The control rule of each local linear servo systems is calculated using pole assignment method proposed by Hikita. Fuzzy method is applied to each local linear servo system and combines it as new control rule. The simulations have been done and the comparisons have been made between the fuzzy servo control and linear servo control. The simulation to study the effect of reference r????0 is done. The comparisons between different values of weight matrix Q _n for fuzzy membership function and disturbance also have been done. The results show that the proposed method can stabilize the system better than linear servo control and follow the reference given. The effect of variant value of values of weight matrix Q _n for fuzzy membership function and disturbance also can be observed.     

Cationization of cellulose fabrics by polyallylamine binding

Novel anion exchange materials was prepared from cellulose fabrics (cotton‐ and rayon‐cloths) by binding polyallylamine to aldehyde groups introduced by partial oxidation of cellulose via sodium periodate treatment. Degree of oxidation (D.O.) was controlled to 2–8% by the amount of oxidant. Polyallylamine (MW: 60,000, 5000, and 1000) was bound to cellulose by reductive amidation via Schiff base formation. Amount of bound amino groups was determined by conductometric titration. With the same cellulose material and degree of oxidation, the level of cationization was strongly dependent on molecular weight of polyallylamine, its concentration, and the pH of reaction mixture. Influence of these factors could be interpreted based on the porous structure of cellulose and behavior of polyallylamine in the solution. In summary, the level of cationization could be maximized by using high concentration of low‐molecular weight polyallylamine under pH as high as possible. The maximum exchange capacity, ～2.5 meq/g, was obtained by a combination of rayon cloth, oxidation degree of 8%, polyallylamine (MW: 1000) concentration of 10% (w/w) in the reaction mixture, and at pH 11.6. The cationized cellulose showed an adsorption capacity of 1.5 g hemoglobin/g cellulose. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1668–1672, 2006