Japanese/English Cross-Language Information Retrieval: Exploration of Query Translation and Transliteration

Cross-language information retrieval (CLIR), where queriesand documents are in different languages, has of late become one ofthe major topics within the information retrieval community. Thispaper proposes a Japanese/English CLIR system, where we combine aquery translation and retrieval modules. We currently target theretrieval of technical documents, and therefore the performance of oursystem is highly dependent on the quality of the translation oftechnical terms. However, the technical term translation is stillproblematic in that technical terms are often compound words, and thusnew terms are progressively created by combining existing basewords. In addition, Japanese often represents loanwords based on itsspecial phonogram. Consequently, existing dictionaries find itdifficult to achieve sufficient coverage. To counter the firstproblem, we produce a Japanese/English dictionary for base words, andtranslate compound words on a word-by-word basis. We also use aprobabilistic method to resolve translation ambiguity. For the secondproblem, we use a transliteration method, which corresponds wordsunlisted in the base word dictionary to their phonetic equivalents inthe target language. We evaluate our system using a test collectionfor CLIR, and show that both the compound word translation andtransliteration methods improve the system performance.     

Dual frequency open-loop electric potential microscopy for local potential measurements in electrolyte solution with high ionic strength

Recent development of open-loop electric potential microscopy (OL-EPM) has enabled to measure local potential distribution at a solid/liquid interface. However, the operating environment of OL-EPM has been limited to a weak electrolyte solution (<1 mM). This has significantly limited its application range in biology and chemistry. To overcome this limitation, we have developed dual frequency (DF) mode OL-EPM. In the method, an ac bias voltage consisting of two frequency components at f(1) and f(2) is applied between a tip and sample. The local potential is calculated from the amplitudes of the f(1) and |f(1) - f(2)| components of the electrostatic force. In contrast to the conventional single frequency (SF) mode OL-EPM, the detection of the 2f(1) component is not required in DF mode. Thus, the maximum bias modulation frequency in DF mode is twice as high as that in SF mode. The high bias modulation frequency used in DF mode prevents the generation of electrochemical reactions and redistribution of ions and water, which enables to operate OL-EPM even in a strong electrolyte solution. In this study, we have performed potential measurements of nanoparticles on a graphite surface in 1 and 10 mM NaCl solution. The results demonstrate that DF mode OL-EPM allows measurements of local potential distribution in 10 mM electrolyte solution.     

High-intensity multi-bunch beam generation by a photo-cathode RF gun

A multi-bunch photo-cathode RF gun system has been developed as an electron source for the production of intense quasi-monochromatic X-rays based on inverse Compton scattering. The desired multi-bunch beam is 100 bunches/pulse with a total charge of 500 nC and a bunch spacing of 2.8 ns. We modified the gun cavity of a ‘BNL-type IV’ RF gun to allow a CsTe cathode plug in the end plate. The system uses a four-dipole chicane beam line to allow the injection of laser light normal to the cathode surface. We compensate the gun cavity beam loading caused by the high-intensity multi-bunch electron beam by injecting the laser pulse before RF power has filled the cavity. We have achieved a total intensity of 220 nC in 100 bunches with a bunch-to-bunch energy spread under 1.3% (peak-to-peak). This paper concentrates on experiments to generate the high-intensity multi-bunch beam with compensation of the bunch-to-bunch energy spread due to heavy beam loading.     

Oxygen permeation properties and surface modification of acceptor-doped CeO2/MnFe2O4 composites

The preparation and oxygen permeation properties of the (Ce_0.8Pr_0.2)O_2−δ − x vol% MnFe₂O₄ composites, where x = 0 to 35, have been investigated. The samples were prepared by the Pechini method. In the case of Ce_0.8Pr_0.2O_2−δ, an oxygen flux density of 6 μmol⋅cm⁻²⋅s⁻¹ (L = 0.0247 cm) and the maximum methane conversion of 50% were attained at 1000^∘C. Unlike composites consisting of Gd-doped CeO₂ and MnFe₂O₄, the oxygen permeability of the (Ce_0.8Pr_0.2)O_2−δ – x vol% MnFe₂O₄ composites was almost constant regardless of the volume fraction of MnFe₂O₄; however, the optimum volume fraction of MnFe₂O₄ was determined to be 5 to 25 in the context of the chemical and mechanical stabilities under methane conversion atmosphere. In addition, the surface modification of the (Ce_0.8Gd_0.2)O_2−δ – 15 vol% MnFe₂O₄ composite was performed by using the FePt nanoparticles. The catalyst loading of 2.8 mg/cm² on the both side of the 0.3 mm-thick (Ce_0.8Gd_0.2)O_2−δ – 15vol% MnFe₂O₄ composite increased the oxygen flux density from 0.30 to 0.76 μmol⋅cm⁻²⋅s⁻¹ in the case of He/air gradients; however, the effect seems to be reduced in the case of high oxygen flux density caused by a large pO₂ gradient. Moreover, the Langmuir-Blodgett film of the FePt nanoparticles were successfully prepared on the tape-cast (Ce_0.8Gd_0.2)O_2−δ – 15vol% MnFe₂O₄ composite. Hydrophobic treatments for the surface of the composite were crucial to achieve high transfer ratio for the deposition of the LB film.     

A novel chromatographic separation technique using tertiary pyridine resin for the partitioning of trivalent actinides and lanthanides

A novel chromatographic separation technique using a tertiary pyridine type resin has been applied to the partitioning of the trivalent actinides (An) and lanthanides (Ln) and several successful results have been shown. In an alcoholic hydrochloric acid system, the trivalent An were clearly separated from the Ln, while no such group separation was achieved in an alcoholic nitric acid system. On the other hand, the nitric acid system was more effective for the intragroup (i.e. individual) separation of the trivalent An and the Ln than the hydrochloric acid system. On the basis of these results, a novel concept for the partitioning of the trivalent An and Ln using the present separation technique and its flowchart have been proposed with its advantages and disadvantages.     

SCARA型机械手的鲁棒防振控制

对ＳＣＡＲＡ型机械手的防振控制进行研究，提出了两自由度鲁棒控制法，应用μ控制理论设计鲁棒反馈控制器，保证了系统的鲁棒稳定性及鲁棒性能指标；基于模型匹配法设计前馈控制器，组成两自由度控制系统，进一步改善了闭环系统的跟踪特性。仿真研究表明，与传统的ＰＤ控制相比，该控制系统能对机械手前端的残留振支进行有效的抑制，取得较好的轨迹跟踪特性。     

Narrow-beam divergence 1.3-μm multiple-quantum-well laser diodeswith monolithically integrated tapered thickness waveguide

This paper describes the optimum design, fabrication, and performance of a 1.3-μm multiple-quantum-well (MQW) laser diode monolithically integrated with a tapered thickness spot-size transformer. The dependence of the lasing characteristics on the thickness distribution of the core layer and on the current injection profile of the device were analyzed. This integrated laser with its optimized structure performed at a low threshold current of 22.2 mA, even at 85°C. The integrated spot-size transformer effectively reduced the lateral and vertical far-field FWHM's to 8° and 9°, respectively. A very long lifetime of over 1×10⁵ h was estimated at 85°C and 8 mW under CW operation     

Effect of atomic oxygen exposure on bubble formation in aluminum alloy

In order to investigate the effect of atomic oxygen exposure of an aluminum alloy on bubble formation during welding, electron beam welding was performed on the samples exposed to atomic oxygen produced by the oxygen plasma method. The change in the aluminum surface due to the exposure was analyzed by auger electron spectroscopy. Due to the exposure of atomic oxygen, the thickness of the aluminum oxide film increases on the surface, and pores are formed during welding. The pores can be formed by the formation of the Al₂O gas through the reaction between the aluminum oxide and aluminum in a high vacuum.     

Combinatorial pulsed laser deposition and thermoelectricity of (La1−xCax)VO3 composition-spread films

La_1−xCa_xVO₃ composition-spread film library was fabricated by combinatorial pulsed laser deposition and their thermoelectric properties were evaluated paralelly by the multi-channel probes of Seebeck coefficient and electric conductivity. Concurrent X-ray analysis verified the formation of solid soluted films in the full composition range (0x1) as judged from the linear variation of the lattice constants. The Seebeck coefficients of La_1−xCa_xVO₃ changed from a large negative value to almost zero with the increase of x, due presumably to the variation of valence in vanadium ions.The power factor in this library was as high as 0.6 μW/cm K², which was obtained at x=0, i.e. pure LaVO₃ grown at 800 °C.