Mean Motions in Ptolemy’s <Emphasis Type="Italic">Planetary Hypotheses</Emphasis>

In the Planetary Hypotheses, Ptolemy summarizes the planetary models that he discusses in great detail in the Almagest, but he changes the mean motions to account for more prolonged comparison of observations. He gives the mean motions in two different forms: first, in terms of ‘simple, unmixed’ periods and next, in terms of ‘particular, complex’ periods, which are approximations to linear combinations of the simple periods. As a consequence, all of the epoch values for the Moon and the planets are different at era Philip. This is in part a consequence of the changes in the mean motions and in part due to changes in Ptolemy’s time in the anomaly, but not the longitude or latitude, of the Moon, the mean longitude of Saturn and Jupiter, but not Mars, and the anomaly of Venus and Mercury, the former a large change, the latter a small one. The pattern of parameter changes we see suggests that the analyses that yielded the Planetary Hypotheses parameters were not the elegant trio analyses of the Almagest but some sort of serial determinations of the parameters based on sequences of independent observations.     

高效快速多种燃气组分色谱分析法

采用热导检测器，通过几种柱的组合．采用多维柱切换系统，并自动完成阀的驱动和信号切换，实现性质不同的人工煤气和液化石油气主要成分一次进样全自动分析，该方法操作简便、分离效果好、灵敏度高、结果准确可靠．     

双周期Riemann边值问题解法的一个注记

解析函数的边值问题是复变函数的重要分支。许多工程技术、力学物理问题可转化为此类问题或奇异积分方程，而后者的求解又与这类问题有着密切的联系，因此它有广泛的应用价值。本文讨论了当G*∈L时双周期Riemann边值问题的求解方法与可解条件。     

Elementary Investigation of Increasing Polarization Performance of Air Electrode for CO2 Transfer

Air electrodes are the key components of Electrochemical carbon dioxide concentrating(EDC) cells. Therefore, the improvement of the polarization performance is beneficial to the increasing of CO2 transfer and cell stability .The preparing process of air electrode is improved by means of the pretreatment of active carbon(AC) and the selection of preparing method of platinum/carbon(Pt/C) powders. Besides, based on the analysis of orthogonal test results, the optimum preparing conditions of Pt/C powders in air electrode are achieved, that is, hydrazine hydrate concentration is 5%～10%, platinum capacity is 8mg/cm2, chloroplatinic acid concentration is 10.0mg/ml and water both temperature is 40℃.     

Performance analysis of optimal channel estimation and multiuser detection in a randomly-spread CDMA channel

<正> This paper analyzes performance of optimal channel estimation and multiuser detection(MUD) in a block-fading code-division multiple-access (CDMA) channel on the assumptions of randomspreading and large-system limit,by using the replica method developed in statistical mechanics.The authors find that the asymptotic spectral efficiency of the linear minimum mean-squared error(LMMSE) MUD which was proposed and analyzed by Evans and Tse in 2000 is indistinguishable fromthat of the optimal MUD for small system loads.Our results imply that performance of MUD scarcelyimproves even if one spends more computational cost than that of the LMMSE MUD,i.e.,at most thecube of the number of users,on the above-described conditions.     

Performance comparison of distributed state estimation algorithms for power systems

A newly proposed distributed dynamic state estimation algorithm based on the maximum a posteriori (MAP) technique is generalised and studied for power systems. The system model involves linear time-varying load dynamics and nonlinear measurements. The main contribution of this paper is to compare the performance and feasibility of this distributed algorithm with several existing distributed state estimation algorithms in the literature. Simulations are tested on the IEEE 39-bus and 118-bus systems under various operating conditions. The results show that this distributed algorithm performs better than distributed quasi-steady state estimation algorithms which do not use the load dynamic model. The results also show that the performance of this distributed method is very close to that by the centralized state estimation method. The merits of this algorithm over the centralized method lie in its low computational complexity and low communication load. Hence, the analysis supports the efficiency and benefits of the distributed algorithm in applications to large-scale power systems.     

Simulation study of SVM-based approach in extracting parameters for electromagnetic detection of buried object

In this paper, a new method for extracting the parameters of buried object is proposed. The center position and dielectric properties of 2-D buried object are estimated by means of a regression technique based on support vector machine (SVM). The proposed method, after a proper training procedure, is able to reconstruct the center position and dielectric properties of a buried object inside a given investigation domain. Numerical simulation results indicate that SVM-based approach shows higher accuracy than the back-propagation neural networks (BPNN) algorithm.     

Synthesis and characterization of bifunctional terbium complex-based nanoparticles

Novel bifunctional terbium complex-based nanoparticles were developed using a modified Stber method and a layer-by-layer assembly process. A magnetic core of Fe3O4 nanoparticles was coated with a silica shell to form the first layer. Then a ternary Tb3+ complex (TESPPA-Tb), which acted as a luminescent marker, was covalently bound to the silica surface by stable Si-O-Si bonds. The TESPPA monomer was synthesized by binding pyridine 2,6-dicarboxylic acid to 3-aminopropyltriethoxysilane, which was used as a ligand for coordination with the Tb3+ ions. An outer shell of silica was applied to the nanoparticles to allow for versatility with surface functionalization. The nanoparticles were characterized by X-ray powder diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, ultravioletvisible spectroscopy, vibration sample magnetometer, and photoluminescence spectroscopy. The bifunctional nanoparticles exhibited favorable superparamagnetic behavior and photoluminescence properties of Tb3+. These nanoparticles have potential applications in biolabeling, bioseparation, immunoassays, and pathogenic diagnosis.     

Research and Reflection: Potential Impact on the Professional Development of Undergraduate Occupational Therapy Students

In occupational therapy education in South Africa, community service (CS) focuses learning opportunities during fieldwork placements. CS therefore enabled the researcher to utilise successive small scale research projects to guide learning of students during fieldwork while simultaneously developing the occupational therapy service at a residential care facility. This community setting provided a powerful environment through which research, in combination with opportunities for reflection, contributed to nurturing skills needed by these future health professionals. A technical action research (AR) approach incorporated AR cycles and opportunities for structured reflection. Therefore situations were created for the students to embrace experiential learning. Experiential learning in the form of anticipatory reflection, reflection-in-action, reflection on reflection and retrospective reflection impacted on the quality of the students’ work. Besides encouraging unique leaning opportunities for students when engaging in research during their fieldwork placement, engagement in AR cycles simultaneously improved service delivery to residents in the facility. Key benefits of this investigation were that fieldwork education utilising AR cycles within a CS situation promoted students to identify voids in their theoretical background as well as practice skills; to apply reflective practice that could contribute to their personal and professional development; and to utilize learning opportunities optimally. Despite positive gains showed by this study, the role of power relations between the researcher as fieldwork educator and the students prohibited the AR cycles from being more emancipatory in nature and should be addressed in follow-up studies.     

Value of Access to Jobs and Amenities: Evidence from New Residential Properties in Beijing

<正>Introduction When households are faced with the choice of where to live in a city, one of the foremost concerns is the loca-tion’s accessibility to jobs and various other amenities, such as schools, hospitals, and parks[1]. A home in a city is a gateway to urban opportunities, and obviously