ロックイン場幅器およびtックスカー積分器は,古くから,雑音に埋もれがちな微少信号の検出に用いられてL1る.その単純さと有用性ゆえに,物性研究で広く使われている基本測定器である.ここでは,その動作原理,利点,使用方法,および最近の動向を紹介する.

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Lock-in amplifier is a useful instrument for recovering small signals buried in noise. This paper describes the principle and an application example of the lock-in amplifier. In addition, it offers some advice on the selection and usage of signal amplifier.

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Features and principle of function generator and characteristics of ARB (Arbitrary Waveform). Examples of trigger oscillation and sequence oscillation with actual product. Brief explanation about typical application in laser field.

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広範囲な負荷や直流電源電圧の変動に対して応答特性が変わらないロバストなPWM電力増幅器が必要になってきている。この論文では、そのような要求を満たすことができるPWMパワーアンプのためのモード·スイッチングを備えたディジタルロバストコントローラーを提案をする。最初に電力増幅部, LCLフィルタ部とPWM信号発生部からなるPWM電力増幅器のノミナルモデルを線形近似する。次に制御対象は入力無駄時間を考慮した離散時間システムとし, 以前に提案された方法によってディジタル·コントローラーが設計することができることを示す。さらに、負荷範囲はモード切換によって広げることができる。モード切換を備えたディジタル制御器をDSPによって実現し実験によってこれを示す.

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雑音に埋もれた信号を測定せねばならないという場面に出くわす読者も多いであろう．干渉を利用して，微弱な信号を測定する方法であるホモダイン検出，ヘテロダイン検出，ロックイン検出について，その原理，特徴を光を題材とした測定例を交えて説明する．

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永久ゴマ加速装置の働きを理解するため,デジタルオシロスコープを用いて電圧の時間変化を測定し,解析を行なった。ベース-エミッタ間電圧においてトランジスタの電流増幅作用がOFFとなっている時間帯に-8V程度の定電圧が生じている。この定電圧は,トランジスタのベース-エミッタ間における電子なだれによるツェデー電圧のあらわれである。ベース-エミッタ間はツェナー電圧8Vのツェナーダイオードとして振舞う。

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A method is proposed for designing a robust controller for PWM power amplifiers, which are widely used as amplifiers themselves and power supplies. The main technical requirements imposed on PWM power amplifiers are linerarity in wide frequency range and well-damped fast dynamic response against extensive load and d. c. power supply variations. Therefore, in order to satisfy the design specifications-linearity in wide frequency range and no overshoots during the transients, an approximate 2-degree-of-freedom integral type control structure is proposed as well as a design procedure for the robust controller is discussed. It is clarified from some simulations and experiments that the designed controller shows highlighted good dynamic performances and effective disturbance rejection properties against external disturbances, i. e. load and power-supply variations.

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リチウムイオン二次電池の合剤スラリーにはPVDFがバインダーとして使われている。電池に要求される性能のパラダイムシフトに伴いPVDFのさらなる改善が求められている。しかしながら、PVDFの簡便な評価方法は見当たらない。本研究ではPVDFのNMP溶液の電気的物性について調査することを目的とし、交流インピーダンス法を使ってPVDFのNMP溶液の電気的物性について調査した。その結果、NMP単体とPVDFを溶解したNMPでは電気的物性が異なり、溶解したPVDFの種類によって低周波領域のインピーダンスに顕著な差が現れることを見出した。

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Harmonic interference problems generated by bulk semiconductor power converters become more serious in power systems as they are widely used in industrial applications. Shunt passive filters consisting of LC tuned filters or shunt active filters using PWM inverters have been used to suppress harmonic currents in distribution systems. In order to install the passive or active filters, it is necessary to exactly find a dominant harmonic source in distribution feeders. A harmonic power on each phase and order at a receiving terminal has been investigated by using a digital power meter including an FFT analyzer. However, the conventional detection method has such a problem that it is difficult to exactly discuss harmonic power flow because the detected harmonic power is much smaller compared with a fundamental active power at the receiving terminal. In this paper, the harmonic power in three phases, which can be detected on real time, is defined by applying the pq theory. Next, it is verified by a digital simulation that the proposed method can discuss harmonic flows more easily than the conventional method. As a result, it is more simple and precise to find the harmonic source. Moreover, measurement errors of the harmonic power is revealed quantitatively, and the validity of the proposed method is demonstrated by digital simulation.

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Loosening of cups is occurred by delamination of coating, wears on coating surfaces or osteolysis. If human bones are supported by artificial porous titanium, implants can be available for patients who are not eligible for application of the implant due to their deteriorated bone strength. It is necessary to investigate interfacial strength and fatigue behavior of coating in order to certify its durability to loading in gaits. This study conducts compression tests and fatigue tests of porous titanium coated by hydroxyapatite (HAp) Compression test revealed that interfacial strength of HAp coating was about 7 to 9 MPa, which was determined by intermittent collapse of trunks in porous titanium ( the region is called "plateau region") Fatigue limit of porous titanium was approximately 2 MPa. Displacements during fatigue processes rapidly increased only at the final stage of the f processesAE measurement detected delamination of HAp coating during the fatigue process, which exhibited cyclic damages in HAp coating at the stress amplitudes within elastic ranges of porous titanium.

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Damage to and fracture of dies of cold forward extrusion of a bolt part former was detected by use of a fractal property of acoustic emission (AE) during a practical manufacturing operation. Two conditions of lubrication, with and without vegetable oil, were employed. A fractal dimension m of AE amplitude was used to detect damage to and fracture of the die. The extrusion rate was set to 100 pcs./min. A decrease in m was observed after a certain number of repetitions of extrusion N under both conditions. Under the condition without vegetable oil, the die insert was completely ruptured by N = 2850. The m took a minimum value at N = 2807, and then increased. The progress of the defects on the surface of the workpiece showed good agreement with the change in m. Under the condition with vegetable oil, the die insert was completely ruptured by N = 11000. A decrease in m was observed at N = 9000. A fast overload fracture with a ratchet mark was mainly observed on the fractured surface of the die insert under the condition without vegetable oil. The region of stable crack propagation around the die radius was dominant under the condition of lubrication with vegetable oil.

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Commutation of a semiconductor power converter connected to distribution network triggers a notching oscillation current in the high frequency region due to system resonance. While the high frequency oscillation causes the power-factor improvement capacitor to produce noise, it is difficult to locate the oscillation source by conventional measurement. We have developed methods for locating the oscillation source and evaluating the extent of the problem by simulating an LC equivalence circuit for the distribution network. This is achieved by utilizing a transfer function and impulse response calculation techniques based on the state-space method.

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近年，医療技術の進歩と政府による医療費適正化計画により入院から退院までの在院日数が短くなっている傾向にあり，患者への負担が少ない低侵襲外科治療の需要は従来に増して増加していくと予想される．このような背景から従来よりも低侵襲な外科手術用エネルギーデバイスの需要が高まっている．よって，本研究では，微細な先端を有する非侵襲的かつ術者の感電や火傷が小さい電気メスの作製を目指す．

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