JPH06318118A - Inspecting device using nuclear magnetic resonance - Google Patents
Inspecting device using nuclear magnetic resonanceInfo
- Publication number
- JPH06318118A JPH06318118A JP6081838A JP8183894A JPH06318118A JP H06318118 A JPH06318118 A JP H06318118A JP 6081838 A JP6081838 A JP 6081838A JP 8183894 A JP8183894 A JP 8183894A JP H06318118 A JPH06318118 A JP H06318118A
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- Prior art keywords
- voltage
- magnetic field
- current
- magnetic resonance
- coil
- Prior art date
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- Magnetic Resonance Imaging Apparatus (AREA)
- Control Of Electrical Variables (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、核磁気共鳴現象を用
い、対象物体中の核スピンの密度分布あるいは緩和時間
分布などを非破壊的に計測する検査装置に係り、特に傾
斜磁場発生用電源の高効率化に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection apparatus for non-destructively measuring the density distribution or relaxation time distribution of nuclear spins in a target object using the nuclear magnetic resonance phenomenon, and more particularly to a gradient magnetic field generating power supply. It is related to high efficiency of.
【０００２】[0002]
【従来の技術】従来、人体などの内部構造を非破壊的に
検査する方法として、Ｘ線ＣＴや超音波撮像装置が広く
利用されて来ている。しかし、最近核磁気共鳴現象を用
い同様の検査を行う試みが成功し、Ｘ線ＣＴや超音波撮
像装置では得られない情報を取得できることが明らかに
なった。さて、このような検査装置においては、検査物
体からの信号を物体各部に対応させて分離・識別する必
要がある。その１つに、検査物体に傾斜磁場を印加し、
物体各部の置かれた静磁場を異ならせ、従って各部の共
鳴周波数を異ならせることで位置情報を得る方法があ
る。図１はその原理を説明するための図である。対象物
体１に傾斜磁場Ｇ1を印加すると、Ｇ1に垂直な線上にあ
る核スピンからの信号を積分した信号強度分布２が、静
磁場Ｈの関数として得られる。核磁気共鳴においては、2. Description of the Related Art Conventionally, an X-ray CT or an ultrasonic imaging apparatus has been widely used as a method for nondestructively inspecting an internal structure of a human body or the like. However, recently, an attempt to carry out a similar examination using the nuclear magnetic resonance phenomenon has succeeded, and it has become clear that information that cannot be obtained by an X-ray CT or an ultrasonic imaging apparatus can be obtained. Now, in such an inspection apparatus, it is necessary to separate / identify the signal from the inspection object in correspondence with each part of the object. One of them is to apply a gradient magnetic field to the inspection object,
There is a method of obtaining position information by making the static magnetic field placed on each part of the object different and thus making the resonance frequency of each part different. FIG. 1 is a diagram for explaining the principle. When the gradient magnetic field G 1 is applied to the target object 1, the signal intensity distribution 2 obtained by integrating the signals from the nuclear spins on the line perpendicular to G 1 is obtained as a function of the static magnetic field H. In nuclear magnetic resonance,
【０００３】[0003]
【数１】 ｆ＝γＨ／（２π） …（数１） の関係が成立するので、信号強度は共鳴周波数ｆの関数
でもある。ここでγは核磁気回転比であり、核に固有の
値である。次に傾斜磁場の印加方向を変えてＧ2を印加
すると、信号強度分布３が得られる。傾斜磁場の印加方
向を種々変化させて同様の信号強度分布すなわち射影デ
ータを求めれば、Ｘ線ＣＴと同様のアルゴリズムによ
り、元の物体１の核スピン密度分布などを知ることがで
きる。Since the relationship of f = γH / (2π) (Equation 1) holds, the signal strength is also a function of the resonance frequency f. Here, γ is the nuclear gyromagnetic ratio, which is a value peculiar to the nucleus. Next, by changing the application direction of the gradient magnetic field and applying G 2 , the signal intensity distribution 3 is obtained. If a similar signal intensity distribution, that is, projection data is obtained by variously changing the application direction of the gradient magnetic field, the nuclear spin density distribution of the original object 1 can be known by the same algorithm as the X-ray CT.
【０００４】このような位置によるＮＭＲ信号の識別の
方法は例えば、ジャーナル・オブ・フィジックス・イー
サイエンティフィック・インストラウメンツ（Ｊ．Ｐ
ｈｙｓ．Ｅ Ｓｃｉ．Ｉｎｓｔｒｕｍ）第１３巻第７４
７〜７５０頁（１９８０年）に掲載された論文に述べら
れている。ところで、このような射影データは、高周波
パルス磁場の印加直後に生じる自由歳差信号（ＦＩＤ）
をフーリエ変換することによって得られる。この時傾斜
磁場の印加方向を高速で切換える必要があり、それに要
する時間は、ＦＩＤの持続時間に比べ十分小さくなけれ
ばならない。この時間は通常１００μｓのオーダーであ
る。A method of discriminating an NMR signal based on such a position is described in, for example, Journal of Physics E Scientific Instruments (JP
hys. E Sci. Instrum) Vol. 13, Vol. 74
It is described in a paper published on pages 7 to 750 (1980). By the way, such projection data is a free precession signal (FID) generated immediately after the application of the high frequency pulsed magnetic field.
Is obtained by Fourier transform of. At this time, it is necessary to switch the application direction of the gradient magnetic field at high speed, and the time required for this must be sufficiently smaller than the duration of the FID. This time is usually on the order of 100 μs.
【０００５】高周波パルス磁場の印加直後の信号を検出
する方法以外に、エコー信号を観測する方法もある。こ
の場合には、傾斜磁場の切換えに要する時間は、ＦＩＤ
の持続時間ではなく、エコー信号の包絡線の減衰時間よ
りも十分小さければよい。通常１ｍｓｅｃ程度の切換え
時間が要求される。Besides the method of detecting the signal immediately after the application of the high frequency pulsed magnetic field, there is also a method of observing the echo signal. In this case, the time required to switch the gradient magnetic field is
Of the echo signal, which is sufficiently smaller than the decay time of the envelope of the echo signal. Normally, a switching time of about 1 msec is required.
【０００６】ところで、傾斜磁場を発生するコイルには
インダクタンスＬがあるため、コイルに流れる電流ｉが
変化したとき、その両端には（数２）で与えられる逆起
電圧Ｖがインダクタンスにより発生する。By the way, since the coil for generating the gradient magnetic field has the inductance L, when the current i flowing through the coil changes, the counter electromotive voltage V given by (Equation 2) is generated at the both ends of the coil due to the inductance.
【０００７】[0007]
【数２】 Ｖ＝−Ｌ（ｄｉ／ｄｔ） …（数２） また、コイルには抵抗Ｒもあるため、結局電流ｉが流れ
た時、コイルの両端に発生する電圧の絶対値の最大値
は、## EQU00002 ## V = -L (di / dt) (Equation 2) Further, since the coil also has a resistance R, the maximum absolute value of the voltage generated across the coil when the current i eventually flows. Is
【０００８】[0008]
【数３】 │Ｖ│＝√〔（Ｒ│ｉ│）2＋（Ｌ│ｄｉ／ｄｔ│）2〕 …（数３） となる。従って、コイルに流す電流を制御するために
は、その電源電圧として（数２）で与えられるＶよりも
大きな電圧が必要である。ところが、ｉが一定のときに
はｄｉ／ｄｔ＝０であるので、Ｖ＝Ｒ│ｉ│となる。一
般に、[Equation 3] | V | = √ [(R | i |) 2 + (L | di / dt |) 2 ] (Equation 3) Therefore, in order to control the current flowing through the coil, a voltage larger than V given by (Equation 2) is required as the power supply voltage. However, when i is constant, di / dt = 0, so V = R | i |. In general,
【０００９】[0009]
【数４】 Ｒ│ｉ│＜√〔（Ｒ│ｉ│）2＋（Ｌ│ｄｉ／ｄｔ│）2〕 …（数４） が成立するので、ｉが変化する時と、一定値をとる時と
では電源に要求される電圧が大幅に異なることになる。
このような条件を、最大電圧に対して満足するようにし
ておくと、電流が変化しない区間においてはコイルの両
端の電圧と最大電圧との差の電圧を電流増幅装置が負担
しなければならず、それ自体の消費電力が非常に大きな
ものとなるという欠点があった。[Equation 4] R | i | <√ [(R | i |) 2 + (L | di / dt |) 2 ] ... (Equation 4) holds, so that when i changes, it takes a constant value. The voltage required for the power supply differs greatly from time to time.
If such a condition is satisfied with respect to the maximum voltage, the current amplifier must bear the voltage difference between the voltage across the coil and the maximum voltage in the section where the current does not change. However, there is a drawback that the power consumption of itself becomes very large.
【００１０】[0010]
【発明が解決しようとする課題】本発明はこのような点
を鑑みてなされたもので、その目的は、傾斜磁場発生用
コイルを駆動する電流増幅装置への電源電圧を、コイル
に流れる電流の変化率に応じて切換え、増幅装置自体で
の損失を小さくして、その効率向上を達成した装置を提
供することにある。SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to supply a power supply voltage to a current amplifying device for driving a coil for generating a gradient magnetic field with a current flowing through the coil. An object of the present invention is to provide a device in which the efficiency is improved by switching according to the rate of change and reducing the loss in the amplifying device itself.
【００１１】[0011]
【課題を解決するための手段】交流電圧がトランスの１
次側端子に加えら、２次側端子に、巻線比に応じて電圧
が発生する。各端子にはトライアック、サイリスタなど
のスイッチング素子が接続される。制御回路により導通
状態か非導通状態かの制御を行ない、整流回路への供給
電圧を変化させる。整流回路の出力は電流増幅回路へ供
給され、電流増幅回路への入力電流波形に応じて傾斜磁
場発生用コイルへ電流を供給する。[Means for Solving the Problems] The AC voltage of the transformer 1
In addition to the secondary side terminal, a voltage is generated at the secondary side terminal according to the winding ratio. A switching element such as a triac or thyristor is connected to each terminal. The control circuit controls the conduction state or the non-conduction state, and changes the supply voltage to the rectifier circuit. The output of the rectifier circuit is supplied to the current amplification circuit, and the current is supplied to the gradient magnetic field generating coil according to the input current waveform to the current amplification circuit.
【００１２】[0012]
【作用】コイルの両端に逆起電圧が発生するのは、電流
値を急激に変化させる時であるから、その区間だけ電源
電圧を高め、他の区間ではより低い電圧に保つことで、
電流増幅装置での消費電力を減少させることが可能とな
る。しかも、電流の変化する時刻はあらかじめ知られて
いるのであるから、電流を変化させる前に電源電圧を変
化させれば、電源電圧の変動による電流増幅装置への干
渉を抑えることもできる。The counter electromotive voltage is generated at both ends of the coil when the current value is rapidly changed. Therefore, by increasing the power supply voltage only in that section and keeping the voltage lower in other sections,
It is possible to reduce the power consumption in the current amplification device. Moreover, since the time at which the current changes is known in advance, if the power supply voltage is changed before changing the current, it is possible to suppress interference with the current amplification device due to fluctuations in the power supply voltage.
【００１３】[0013]
【実施例】以下図を参照しながら本発明の実施例につい
て説明する。図２は本発明の一実施例である検査装置の
概略構成を示すものである。制御装置４は各装置へ種々
の命令を一定のタイミングで出力する。高周波パルス発
生器５の出力は電力増幅器６で増幅され、高周波磁場発
生用コイル７を励振する。該コイル７は同時に受信コイ
ルを兼ねており、該コイル７で検出された信号成分は増
幅器８を通り、検波器９で検波後、信号処理装置１０で
画像に変換・表示される。高周波パルス発生器５からの
出力は、検波器９で直角位相検波を行うときの基準信号
としても用いられる。Ｚ方向及びそれに垂直な方向の傾
斜磁場の発生は、傾斜磁場発生用コイル１１、１２、１
３で行ない、該コイルは電源１４、１５、１６で駆動さ
れる。検査対象である人体１７はベッド１８上に置か
れ、支持台１９上を移動する。静磁場は静磁場発生用コ
イル２０で発生させ、このコイルは電源２１で駆動され
る。Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows a schematic configuration of an inspection apparatus which is an embodiment of the present invention. The control device 4 outputs various commands to each device at a constant timing. The output of the high frequency pulse generator 5 is amplified by the power amplifier 6 to excite the high frequency magnetic field generating coil 7. The coil 7 also functions as a receiving coil at the same time. The signal component detected by the coil 7 passes through the amplifier 8, is detected by the wave detector 9, and is then converted and displayed as an image by the signal processor 10. The output from the high frequency pulse generator 5 is also used as a reference signal when the detector 9 performs quadrature phase detection. The generation of the gradient magnetic field in the Z direction and the direction perpendicular thereto is performed by the gradient magnetic field generating coils 11, 12, 1
3 and the coils are driven by power supplies 14, 15, 16. The human body 17 to be inspected is placed on the bed 18 and moves on the support 19. The static magnetic field is generated by the static magnetic field generating coil 20, and this coil is driven by the power supply 21.
【００１４】さて、ここで傾斜磁場発生用コイル１１を
駆動する電源１４について詳しく述べる。図３は駆動電
源１４の構成を示すものである。商用交流電圧がトラン
ス２２の１次側端子２３に加えられると、２次側端子２
４、２５には、それぞれの巻線比に応じて電圧が発生す
る。各端子にはトライアック、サイリスタなどのスイッ
チング素子２６、２７が接続されており、制御回路２
８、２９により導通状態か非導通状態になり、整流回路
３０への供給電圧を変化させる。整流回路３０を通った
出力は電流増幅回路３１へ供給され、電流増幅回路３１
への入力電流波形に応じてコイル１１へ電流を供給す
る。Now, the power supply 14 for driving the gradient magnetic field generating coil 11 will be described in detail. FIG. 3 shows the configuration of the driving power supply 14. When the commercial AC voltage is applied to the primary side terminal 23 of the transformer 22, the secondary side terminal 2
Voltages are generated in the coils 4 and 25 in accordance with the respective winding ratios. Switching devices 26 and 27 such as triacs and thyristors are connected to the respective terminals, and the control circuit 2
Conductive state or non-conductive state is caused by 8 and 29, and the supply voltage to the rectifier circuit 30 is changed. The output that has passed through the rectifier circuit 30 is supplied to the current amplifier circuit 31,
A current is supplied to the coil 11 according to the input current waveform to the coil.
【００１５】いまコイル１１へ流す電流波形を図４(a)
に示されるものとする。時刻ｔ0から電流が流れはじ
め、ｔ1でｉ0に達した後、ｔ2までその値を保ち、その
後減少してｔ3で零になるものである。このときコイル
１１の両端にインダクタンスＬにより発生する電圧Ｖは
図４(b)で示されるものとなり、直流抵抗分Ｒを考慮し
たコイルの両端の電圧は図４(c)で示されるものとな
る。ここで発生電圧の最大値をＶP、一定値となるとき
の値をＶSとする。従って、電流増幅回路３１へ供給さ
れる整流回路３０からの出力には少なくともＶP以上の
電圧が必要とされることになる。ところが、電流値が急
激に変化するｔ0〜ｔ1区間とｔ2〜ｔ3区間を除くと、電
流増幅回路３１への供給電圧はＶS以上であればよいこ
とになる。ところで従来までは電流増幅回路への供給電
圧ＶはＶP以上の一定値に固定されていたため、区間ｔ1
〜ｔ2に於てはその差Ｖ−ＶSを電流増幅回路３１が負担
することになり、増幅回路としての消費電力が極めて大
きくなり、装置も大規模とならざるを得なかった。The waveform of the current flowing through the coil 11 is shown in FIG. 4 (a).
Shall be shown in. The current starts to flow from time t 0 , reaches i 0 at t 1 , maintains that value until t 2 , then decreases and becomes zero at t 3 . At this time, the voltage V generated by the inductance L across the coil 11 is as shown in FIG. 4 (b), and the voltage across the coil considering the DC resistance R is as shown in FIG. 4 (c). . Here, the maximum value of the generated voltage is V P , and the value when it becomes a constant value is V S. Therefore, the output from the rectifier circuit 30 supplied to the current amplifier circuit 31 requires a voltage of at least V P or higher. However, except for the sections t 0 to t 1 and t 2 to t 3 where the current value changes abruptly, the voltage supplied to the current amplification circuit 31 may be V S or more. By the way, until now, the voltage V supplied to the current amplifier circuit was fixed at a constant value equal to or higher than V P , and therefore the interval t 1
~t is At a 2 will be the difference V-V S current amplification circuit 31 is borne, power consumption of the amplifier circuit becomes extremely large, device also unavoidably large.
【００１６】しかし、本発明においては、図３に示すト
ランス２２の２次側出力を、コイル１１へ流す電流波形
に応じて切換えることにより、そのような欠点を除去す
ることが可能となった。すなわち、図３においてスイッ
チング素子を制御する回路２８、２９には、このいずれ
かを選択する回路３２が接続されており、ゲート回路３
２にはＲＡＭあるいはＲＯＭ３３からの信号が加えられ
ている。このＲＡＭあるいはＲＯＭ３３には傾斜磁場発
生用コイルに流す電流波形に関係した図４(d)に示す波
形が記憶されている。この波形について簡単な説明を加
える。However, in the present invention, such a defect can be eliminated by switching the secondary side output of the transformer 22 shown in FIG. 3 according to the current waveform flowing to the coil 11. That is, in FIG. 3, a circuit 32 for selecting one of these is connected to the circuits 28 and 29 for controlling the switching elements, and the gate circuit 3 is connected.
A signal from the RAM or the ROM 33 is added to 2. The RAM or ROM 33 stores the waveform shown in FIG. 4 (d), which is related to the waveform of the current flowing through the gradient magnetic field generating coil. A brief description of this waveform will be added.
【００１７】図４(d)に示されるようにｔ0′（＜ｔ0）
の時刻においてｖhとなりｔ1′まで続く。その後はｖL
となり、次にｔ2′の時刻で再びｖhとなりｔ3′まで続
く。さて、このような波形がゲート回路３２に入力され
ると、このゲート回路３２はその値に応じて、制御回路
２８か２９のいずれかを選択し、スイッチング素子２６
か２７のいずれかを導通状態にする。これにより電流増
幅回路３１へ供給される電圧が図４(e)に示すように変
化するのである。As shown in FIG. 4D, t 0 ′ (<t 0 ).
At the time of, it becomes v h and continues until t 1 ′. Then v L
Then, at the time of t 2 ′, v h becomes again and continues until t 3 ′. Now, when such a waveform is input to the gate circuit 32, the gate circuit 32 selects either the control circuit 28 or 29 according to the value, and the switching element 26 is selected.
Either one of the two is brought into conduction. As a result, the voltage supplied to the current amplification circuit 31 changes as shown in FIG.
【００１８】しかも、傾斜磁場発生用コイルに流す電流
波形はあらかじめ知られているのであるから、スイッチ
ング素子を駆動するタイミングを、電流が急峻に変化す
る時点よりも前に選び、電流増幅回路３１への供給電圧
がコイルの駆動に十分な大きさになるように準備してお
くことも可能になってくる。Moreover, since the waveform of the current flowing through the gradient magnetic field generating coil is known in advance, the timing for driving the switching element is selected before the time when the current sharply changes, and the current amplification circuit 31 is selected. It is also possible to prepare so that the supply voltage of is large enough to drive the coil.
【００１９】図５は本発明の他の実施例であり、電流増
幅回路３１への供給電圧を変化させる方法として、交流
電圧を切換えるのではなく、整流回路３１′、３１″を
通った後でスイッチング素子２６、２７により電圧が切
換わるものである。なお、図３においてはトランス２２
の２次側端子を切換えるかわりに、１次側端子にタップ
を付加し、それを切換えても全く同様に動作することは
いうまでもない。FIG. 5 shows another embodiment of the present invention. As a method of changing the supply voltage to the current amplification circuit 31, instead of switching the AC voltage, after passing through the rectification circuits 31 'and 31 ". The voltage is switched by the switching elements 26 and 27. Incidentally, in FIG.
It goes without saying that, instead of switching the secondary side terminal of, the tap is added to the primary side terminal and the tap is switched, the same operation is performed.
【００２０】[0020]
【発明の効果】本発明によれば、傾斜磁場発生用コイル
を駆動する電流増幅器での消費電力を減少させるので、
装置の小型化、高信頼化、高効率化を達成することがで
きた。According to the present invention, since the power consumption of the current amplifier for driving the gradient magnetic field generating coil is reduced,
We were able to achieve downsizing, high reliability, and high efficiency of the device.
【図１】イメージングの原理を説明する図。FIG. 1 is a diagram illustrating the principle of imaging.
【図２】本発明の一実施例の検査装置の概略構成を示す
図。FIG. 2 is a diagram showing a schematic configuration of an inspection apparatus according to an embodiment of the present invention.
【図３】本発明の駆動電源の構成を示す図。FIG. 3 is a diagram showing a configuration of a driving power supply of the present invention.
【図４】傾斜磁場発生用コイルに流す電流波形とコイル
端子電圧を示す図。FIG. 4 is a diagram showing a waveform of a current passed through a coil for generating a gradient magnetic field and a coil terminal voltage.
【図５】本発明の他の実施例の回路図。FIG. 5 is a circuit diagram of another embodiment of the present invention.
４…制御装置、５…高周波パルス発生器、６…電力増幅
器、７…高周波磁場発生用コイル、１０…信号処理装
置、２１…電源。4 ... Control device, 5 ... High frequency pulse generator, 6 ... Power amplifier, 7 ... High frequency magnetic field generating coil, 10 ... Signal processing device, 21 ... Power supply.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 河野 秀樹 東京都国分寺市東恋ケ窪１丁目280番地 株式会社日立製作所中央研究所内 (72)発明者 津田 宗孝 茨城県勝田市市毛882番地 株式会社日立 製作所那珂工場内 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Hideki Kono 1-280, Higashi Koikekubo, Kokubunji City, Tokyo Metropolitan Research Laboratory, Hitachi, Ltd. in the factory
Claims (4)
場発生手段と、検査対象からの核磁気共鳴信号を検出す
る信号検出手段と、該信号検出手段による検出信号の演
算を行う計算機および該計算機による演算結果の出力手
段を有する核磁気共鳴を用いた検査装置において、あら
かじめ定められた時間変化をもつ電流波形の電流が傾斜
磁場発生用コイルに流され、前記電流波形の変化率に応
じて、前記傾斜磁場発生用コイルを駆動する電流増幅器
への供給電源の電圧を変化させる電圧制御手段を設けた
ことを特徴とする核磁気共鳴を用いた検査装置。1. A magnetic field generating means for static magnetic field, gradient magnetic field and high frequency magnetic field, signal detecting means for detecting a nuclear magnetic resonance signal from an inspection target, a computer for calculating a detection signal by the signal detecting means, and In an inspection apparatus using nuclear magnetic resonance having a means for outputting a calculation result by a computer, a current having a current waveform having a predetermined time change is passed through a gradient magnetic field generating coil, and the current waveform changes in accordance with the rate of change of the current waveform. An inspection apparatus using nuclear magnetic resonance, comprising voltage control means for changing a voltage of a power supply to a current amplifier for driving the gradient magnetic field generating coil.
時点よりも以前に、前記傾斜磁場発生用コイルの駆動を
可能とする電圧に、前記供給電源の電圧を変化させるこ
とを特徴とする請求項１に記載の核磁気共鳴を用いた検
査装置。2. The voltage control means changes the voltage of the power supply to a voltage that enables driving of the gradient magnetic field generating coil before the time when the change rate changes. An inspection apparatus using the nuclear magnetic resonance according to claim 1.
または２次側に設けられた端子であり、該端子の切換え
により、前記供給電源の電圧を変化させることを特徴と
する請求項１に記載の核磁気共鳴を用いた検査装置。3. The voltage control means is a terminal provided on a primary side or a secondary side of a power transformer, and the voltage of the power supply is changed by switching the terminal. An inspection apparatus using the nuclear magnetic resonance described in 1.
流増幅器への供給電源の電圧を制御するための、制御デ
ータを記憶する記憶手段を有することを特徴とする請求
項１に記載の核磁気共鳴を用いた検査装置。4. The kernel according to claim 1, further comprising storage means for storing control data, which is generated based on the current waveform and controls the voltage of a power supply to the current amplifier. Inspection device using magnetic resonance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6081838A JP2501179B2 (en) | 1994-04-20 | 1994-04-20 | Inspection equipment using nuclear magnetic resonance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP6081838A JP2501179B2 (en) | 1994-04-20 | 1994-04-20 | Inspection equipment using nuclear magnetic resonance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH06318118A true JPH06318118A (en) | 1994-11-15 |
| JP2501179B2 JP2501179B2 (en) | 1996-05-29 |
Family
ID=13757618
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6081838A Expired - Lifetime JP2501179B2 (en) | 1994-04-20 | 1994-04-20 | Inspection equipment using nuclear magnetic resonance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2501179B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09276251A (en) * | 1995-12-29 | 1997-10-28 | General Electric Co <Ge> | Gradient amplifier device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS51143817A (en) * | 1975-06-06 | 1976-12-10 | Kokusai Electric Co Ltd | Power supply for pulse motor |
-
1994
- 1994-04-20 JP JP6081838A patent/JP2501179B2/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS51143817A (en) * | 1975-06-06 | 1976-12-10 | Kokusai Electric Co Ltd | Power supply for pulse motor |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09276251A (en) * | 1995-12-29 | 1997-10-28 | General Electric Co <Ge> | Gradient amplifier device |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2501179B2 (en) | 1996-05-29 |
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