方形波

関: square pulse

WordNet

raise to the second power
(geometry) a plane rectangle with four equal sides and four right angles; a four-sided regular polygon; "you can compute the area of a square if you know the length of its sides" (同)foursquare
the product of two equal terms; "nine is the second power of three"; "gravity is inversely proportional to the square of the distance" (同)second power
make square; "Square the circle"; "square the wood with a file" (同)square_up
something approximating the shape of a square
a hand tool consisting of two straight arms at right angles; used to construct or test right angles; "the carpenter who built this room must have lost his square"
any artifact having a shape similar to a plane geometric figure with four equal sides and four right angles; "a checkerboard has 64 squares"
someone who doesnt understand what is going on (同)lame
a formal and conservative person with old-fashioned views (同)square toes
rigidly conventional or old-fashioned (同)straight
without evasion or compromise; "a square contradiction"; "he is not being as straightforward as it appears" (同)straightforward, straight
be compatible with; "one idea squares with another"
cause to match, as of ideas or acts
having four equal sides and four right angles or forming a right angle; "a square peg in a round hole"; "a square corner"
leaving no balance; "my account with you is now all square"
pay someone and settle a debt; "I squared with him"
position so as to be square; "He squared his shoulders"
an undulating curve (同)undulation
a persistent and widespread unusual weather condition (especially of unusual temperatures); "a heat wave"
set waves in; "she asked the hairdresser to wave her hair"
a movement like that of a sudden occurrence or increase in a specified phenomenon; "a wave of settlers"; "troops advancing in waves"
one of a series of ridges that moves across the surface of a liquid (especially across a large body of water) (同)moving ridge
(physics) a movement up and down or back and forth (同)undulation
the act of signaling by a movement of the hand (同)waving, wafture
a hairdo that creates undulations in the hair
something that rises rapidly; "a wave of emotion swept over him"; "there was a sudden wave of buying before the market closed"; "a wave of conservatism in the country led by the hard right"
a member of the womens reserve of the United States Navy; originally organized during World War II but now no longer a separate branch
having been made square

PrepTutorEJDIC

『正方形』;四角な物;(チェス・チェッカーなどの盤の,正方形の)目,ます目 / (四角い)『広場』(街路の交差点にあって,しばしば中央に植木や芝などが植えてあり,小公園になっている);《おもに英》広場の回りの建物(街路)(《略》Sq.) / (四方を街路で囲まれた方形の)一区画,ブロック / 直角定規,かね尺 / (数の)『2乗』,平方(《略》sq.) / 《俗》旧式な人 / 『正方形の』,四角な,直角の,直角をなす / 角ばった,がっかりした / 『平方の』,2乗の(《略》『sq.』) / 《補語にのみ用いて》対等の,五分五分の(even);貸し借りにない / 正直な(honest),公正な(fair),正しい(just) / 率直な,はっきりした,きっぱりした(direct) / 実質のある,十分な / 《俗》しゃちほこばった / =squarely / …‘を'正方形(四角)にする;直角にする / …‘を'正方形(四角)に区切る《+『off』+『名』,+『名』+『off』》 / 〈肩・ひじなど〉‘を'張る / (人と)〈勘定〉‘を'決済する,清算する《+『名』〈勘定〉+『with』+『名』〈人〉》 / (…と)…‘を'一致させる,適合させる《+『名』+『with』+『名』》 / 《受動態で》〈数〉‘を'2乗する;〈ある形・図形など〉‘の'平方積(面積)を求める / 〈人〉‘を'買収する,抱き込む,…‘に'わいろを使う / 〈試合の得点〉‘を'同点にする / (…と)一致する,適合する《+『with』+『名』》
(前後左右・上下に)『揺れる』,ひらめく,ひらひらする / (波形に)『起伏する』,うねる / (手・旗などを振って)『合図する』,手を振る;(…のために,…に向かって)手を振る《+in(to, at)+名》 / (に向かって)‘…を'振る,揺り動かす,ひらめかす《+名+at+名》 / 《方向を表す副詞[句]を伴って》(手・旗などを振って)〈人〉‘に'『合図する』 / ‘…を'起伏させる,うねらせる:〈頭髪〉‘を'ウエーブさせる / 『波』,波浪 / (…の)『波のような動き』,うねり《+of+名》 / (感情・景気などの一時的な)高まり,強まり;(寒暑の)急激な波《+of+名》 / (手・旗などを)振ること,振ってする合図;(…を)振ること《+of+名》 / (髪の)縮れ,ウエーブ / (光・音・電気などの)波

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2017/09/07 20:47:20」(JST)

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[Wiki en表示]

Sine, square, triangle, and sawtooth waveforms

A square wave is a non-sinusoidal periodic waveform (which can be represented as an infinite summation of sinusoidal waves), in which the amplitude alternates at a steady frequency between fixed minimum and maximum values, with the same duration at minimum and maximum. The transition between minimum to maximum is instantaneous for an ideal square wave; this is not realizable in physical systems. Square waves are often encountered in electronics and signal processing. Its stochastic counterpart is a two-state trajectory. A similar but not necessarily symmetric wave, with arbitrary durations at minimum and maximum, is called a pulse wave (of which the square wave is a special case).

The ratio of the high period to the total period of any rectangular wave is called the duty cycle. A true square wave has a 50% duty cycle (equal high and low periods). The average level of a rectangular wave is also given by the duty cycle, therefore by varying the on and off periods and then averaging these said periods, it is possible to represent any value between the two limiting levels. This is the basis of pulse width modulation.

Origin and uses

Square waves are universally encountered in digital switching circuits and are naturally generated by binary (two-level) logic devices. They are used as timing references or "clock signals", because their fast transitions are suitable for triggering synchronous logic circuits at precisely determined intervals. However, as the frequency-domain graph shows, square waves contain a wide range of harmonics; these can generate electromagnetic radiation or pulses of current that interfere with other nearby circuits, causing noise or errors. To avoid this problem in very sensitive circuits such as precision analog-to-digital converters, sine waves are used instead of square waves as timing references.

In musical terms, they are often described as sounding hollow, and are therefore used as the basis for wind instrument sounds created using subtractive synthesis. Additionally, the distortion effect used on electric guitars clips the outermost regions of the waveform, causing it to increasingly resemble a square wave as more distortion is applied.

Simple two-level Rademacher functions are square waves.

Definitions

The square wave in mathematics has many definitions, which are equivalent except at the discontinuities:

It can be defined as simply the sign function of a periodic function, an example being a sinusoid:

\ x(t)=\operatorname {sgn}(\sin[t])

\ v(t)=\operatorname {sgn}(\cos[t])

which will be 1 when the sinusoid is positive, −1 when the sinusoid is negative, and 0 at the discontinuities. Any periodic function can substitute the sinusoid in this definition.

A square wave can also be defined with respect to the Heaviside step function u(t) or the rectangular function ⊓(t):

\ x(t)=\sum _{n=-\infty }^{+\infty }\sqcap (t-nT)=\sum _{n=-\infty }^{+\infty }\left(u\left[t-nT+{1 \over 2}\right]-u\left[t-nT-{1 \over 2}\right]\right)

T is 2 for a 50% duty cycle. It can also be defined in a piecewise way:

\ x(t)={\begin{cases}1,&|t|<T_{1}\,&T_{1}<|t|\leq {1 \over 2}T\end{cases}}

when

\ x(t+T)=x(t)

In terms of sine and cosecant with period p and amplitude a:

y(x)=a\times \csc \left({\frac {2\pi }{p}}x\right)\left\vert \sin \left({\frac {2\pi }{p}}x\right)\right\vert

A square wave can also be generated using the floor function in the following two ways:

Directly:

y(x)=m\left(2\lfloor \nu x\rfloor -\lfloor 2\nu x\rfloor +1\right)

And indirectly:

y(x)=m\left(-1\right)^{\lfloor \nu x\rfloor },

where m is the magnitude and ν is the frequency.

Note: y = atan sin x + acot sin x

Fourier analysis

The six arrows represent the first six terms of the Fourier series of a square wave. The two circles at the bottom represent the exact square wave (blue) and its Fourier-series approximation (purple).

(Odd) harmonics of a 1000 Hz square wave

A square wave can be expressed as the limit case of an infinite series of sinusoidal waves, with fast convergence.

Using Fourier expansion with cycle frequency $f$ over time $t$ , we can represent an ideal square wave with an amplitude of 1 as an infinite series of the form

{\begin{aligned}x_{\text{square}}(t)&={\frac {4}{\pi }}\sum _{k=1}^{\infty }{\frac {\sin \left(2\pi (2k-1)ft\right)}{2k-1}}\\&={\frac {4}{\pi }}\left(\sin(2\pi ft)+{\frac {1}{3}}\sin(6\pi ft)+{\frac {1}{5}}\sin(10\pi ft)+\dots \right).\end{aligned}}

Additive square demo

220 Hz square wave created by harmonics added every second over sine wave

Problems playing this file? See media help.

The ideal square wave contains only components of odd-integer harmonic frequencies (of the form $2π(2 k - 1) f$ ). Sawtooth waves and real-world signals contain all integer harmonics.

A curiosity of the convergence of the Fourier series representation of the square wave is the Gibbs phenomenon. Ringing artifacts in non-ideal square waves can be shown to be related to this phenomenon. The Gibbs phenomenon can be prevented by the use of σ-approximation, which uses the Lanczos sigma factors to help the sequence converge more smoothly.

An ideal mathematical square wave changes between the high and the low state instantaneously, and without under- or over-shooting. This is impossible to achieve in physical systems, as it would require infinite bandwidth.

Animation of the additive synthesis of a square wave with an increasing number of harmonics

Square waves in physical systems have only finite bandwidth and often exhibit ringing effects similar to those of the Gibbs phenomenon or ripple effects similar to those of the σ-approximation.

For a reasonable approximation to the square-wave shape, at least the fundamental and third harmonic need to be present, with the fifth harmonic being desirable. These bandwidth requirements are important in digital electronics, where finite-bandwidth analog approximations to square-wave-like waveforms are used. (The ringing transients are an important electronic consideration here, as they may go beyond the electrical rating limits of a circuit or cause a badly positioned threshold to be crossed multiple times.)

Square wave sound sample

5 seconds of square wave at 1 kHz

Problems playing this file? See media help.

Characteristics of imperfect square waves

As already mentioned, an ideal square wave has instantaneous transitions between the high and low levels. In practice, this is never achieved because of physical limitations of the system that generates the waveform. The times taken for the signal to rise from the low level to the high level and back again are called the rise time and the fall time respectively.

If the system is overdamped, then the waveform may never actually reach the theoretical high and low levels, and if the system is underdamped, it will oscillate about the high and low levels before settling down. In these cases, the rise and fall times are measured between specified intermediate levels, such as 5% and 95%, or 10% and 90%. The bandwidth of a system is related to the transition times of the waveform; there are formulas allowing one to be determined approximately from the other.

External links

Square Wave Approximated by Sines Interactive demo of square wave synthesis using sine waves.
Flash applets Square wave.

,&T_{1}<|t|\leq {1 \over 2}T\end{cases}}}</annotation>

 </semantics>

</math>

when

<math xmlns="http://www.w3.org/1998/Math/MathML" > <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mtext> </mtext> <mi>x</mi> <mo stretchy="false">(</mo> <mi>t</mi> <mo>+</mo> <mi>T</mi> <mo stretchy="false">)</mo> <mo>=</mo> <mi>x</mi> <mo stretchy="false">(</mo> <mi>t</mi> <mo stretchy="false">)</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle \ x(t+T)=x(t)}</annotation> </semantics> </math>

In terms of sine and cosecant with period p and amplitude a:

<math xmlns="http://www.w3.org/1998/Math/MathML" > <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>y</mi> <mo stretchy="false">(</mo> <mi>x</mi> <mo stretchy="false">)</mo> <mo>=</mo> <mi>a</mi> <mo>×</mo> <mi>csc</mi> <mo>⁡</mo> <mrow> <mo>(</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mn>2</mn> <mi>π</mi> </mrow> <mi>p</mi> </mfrac> </mrow> <mi>x</mi> <mo>)</mo> </mrow> <mrow> <mo>|</mo> <mi>sin</mi> <mo>⁡</mo> <mrow> <mo>(</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mn>2</mn> <mi>π</mi> </mrow> <mi>p</mi> </mfrac> </mrow> <mi>x</mi> <mo>)</mo> </mrow> <mo>|</mo> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle y(x)=a\times \csc \left({\frac {2\pi }{p}}x\right)\left\vert \sin \left({\frac {2\pi }{p}}x\right)\right\vert }</annotation> </semantics> </math>

A square wave can also be generated using the floor function in the following two ways:

Directly:

<math xmlns="http://www.w3.org/1998/Math/MathML" > <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>y</mi> <mo stretchy="false">(</mo> <mi>x</mi> <mo stretchy="false">)</mo> <mo>=</mo> <mi>m</mi> <mrow> <mo>(</mo> <mn>2</mn> <mo fence="false" stretchy="false">⌊</mo> <mi>ν</mi> <mi>x</mi> <mo fence="false" stretchy="false">⌋</mo> <mo>−</mo> <mo fence="false" stretchy="false">⌊</mo> <mn>2</mn> <mi>ν</mi> <mi>x</mi> <mo fence="false" stretchy="false">⌋</mo> <mo>+</mo> <mn>1</mn> <mo>)</mo> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle y(x)=m\left(2\lfloor \nu x\rfloor -\lfloor 2\nu x\rfloor +1\right)}</annotation> </semantics> </math>

And indirectly:

<math xmlns="http://www.w3.org/1998/Math/MathML" > <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mi>y</mi> <mo stretchy="false">(</mo> <mi>x</mi> <mo stretchy="false">)</mo> <mo>=</mo> <mi>m</mi> <msup> <mrow> <mo>(</mo> <mo>−</mo> <mn>1</mn> <mo>)</mo> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mo fence="false" stretchy="false">⌊</mo> <mi>ν</mi> <mi>x</mi> <mo fence="false" stretchy="false">⌋</mo> </mrow> </msup> <mo>,</mo> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle y(x)=m\left(-1\right)^{\lfloor \nu x\rfloor },}</annotation> </semantics> </math>

where m is the magnitude and ν is the frequency.

Note: y = atan sin x + acot sin x

Fourier analysis

The six arrows represent the first six terms of the Fourier series of a square wave. The two circles at the bottom represent the exact square wave (blue) and its Fourier-series approximation (purple).

(Odd) harmonics of a 1000 Hz square wave

A square wave can be expressed as the limit case of an infinite series of sinusoidal waves, with fast convergence.

Using Fourier expansion with cycle frequency $f$ over time $t$ , we can represent an ideal square wave with an amplitude of 1 as an infinite series of the form

<math xmlns="http://www.w3.org/1998/Math/MathML" > <semantics> <mrow class="MJX-TeXAtom-ORD"> <mstyle displaystyle="true" scriptlevel="0"> <mrow class="MJX-TeXAtom-ORD"> <mtable columnalign="right left right left right left right left right left right left" rowspacing="3pt" columnspacing="0em 2em 0em 2em 0em 2em 0em 2em 0em 2em 0em" displaystyle="true"> <mtr> <mtd> <msub> <mi>x</mi> <mrow class="MJX-TeXAtom-ORD"> <mtext>square</mtext> </mrow> </msub> <mo stretchy="false">(</mo> <mi>t</mi> <mo stretchy="false">)</mo> </mtd> <mtd> <mi></mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>4</mn> <mi>π</mi> </mfrac> </mrow> <munderover> <mo>∑</mo> <mrow class="MJX-TeXAtom-ORD"> <mi>k</mi> <mo>=</mo> <mn>1</mn> </mrow> <mrow class="MJX-TeXAtom-ORD"> <mi mathvariant="normal">∞</mi> </mrow> </munderover> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mrow> <mi>sin</mi> <mo>⁡</mo> <mrow> <mo>(</mo> <mn>2</mn> <mi>π</mi> <mo stretchy="false">(</mo> <mn>2</mn> <mi>k</mi> <mo>−</mo> <mn>1</mn> <mo stretchy="false">)</mo> <mi>f</mi> <mi>t</mi> <mo>)</mo> </mrow> </mrow> <mrow> <mn>2</mn> <mi>k</mi> <mo>−</mo> <mn>1</mn> </mrow> </mfrac> </mrow> </mtd> </mtr> <mtr> <mtd /> <mtd> <mi></mi> <mo>=</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>4</mn> <mi>π</mi> </mfrac> </mrow> <mrow> <mo>(</mo> <mi>sin</mi> <mo>⁡</mo> <mo stretchy="false">(</mo> <mn>2</mn> <mi>π</mi> <mi>f</mi> <mi>t</mi> <mo stretchy="false">)</mo> <mo>+</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mn>3</mn> </mfrac> </mrow> <mi>sin</mi> <mo>⁡</mo> <mo stretchy="false">(</mo> <mn>6</mn> <mi>π</mi> <mi>f</mi> <mi>t</mi> <mo stretchy="false">)</mo> <mo>+</mo> <mrow class="MJX-TeXAtom-ORD"> <mfrac> <mn>1</mn> <mn>5</mn> </mfrac> </mrow> <mi>sin</mi> <mo>⁡</mo> <mo stretchy="false">(</mo> <mn>10</mn> <mi>π</mi> <mi>f</mi> <mi>t</mi> <mo stretchy="false">)</mo> <mo>+</mo> <mo>…</mo> <mo>)</mo> </mrow> <mo>.</mo> </mtd> </mtr> </mtable> </mrow> </mstyle> </mrow> <annotation encoding="application/x-tex">{\displaystyle {\begin{aligned}x_{\text{square}}(t)&={\frac {4}{\pi }}\sum _{k=1}^{\infty }{\frac {\sin \left(2\pi (2k-1)ft\right)}{2k-1}}\\&={\frac {4}{\pi }}\left(\sin(2\pi ft)+{\frac {1}{3}}\sin(6\pi ft)+{\frac {1}{5}}\sin(10\pi ft)+\dots \right).\end{aligned}}}</annotation> </semantics> </math>

Additive square demo

220 Hz square wave created by harmonics added every second over sine wave

Problems playing this file? See media help.

The ideal square wave contains only components of odd-integer harmonic frequencies (of the form $2π(2 k - 1) f$ ). Sawtooth waves and real-world signals contain all integer harmonics.

A curiosity of the convergence of the Fourier series representation of the square wave is the Gibbs phenomenon. Ringing artifacts in non-ideal square waves can be shown to be related to this phenomenon. The Gibbs phenomenon can be prevented by the use of σ-approximation, which uses the Lanczos sigma factors to help the sequence converge more smoothly.

An ideal mathematical square wave changes between the high and the low state instantaneously, and without under- or over-shooting. This is impossible to achieve in physical systems, as it would require infinite bandwidth.

Animation of the additive synthesis of a square wave with an increasing number of harmonics

Square waves in physical systems have only finite bandwidth and often exhibit ringing effects similar to those of the Gibbs phenomenon or ripple effects similar to those of the σ-approximation.

For a reasonable approximation to the square-wave shape, at least the fundamental and third harmonic need to be present, with the fifth harmonic being desirable. These bandwidth requirements are important in digital electronics, where finite-bandwidth analog approximations to square-wave-like waveforms are used. (The ringing transients are an important electronic consideration here, as they may go beyond the electrical rating limits of a circuit or cause a badly positioned threshold to be crossed multiple times.)

Square wave sound sample

5 seconds of square wave at 1 kHz

Problems playing this file? See media help.

Characteristics of imperfect square waves

As already mentioned, an ideal square wave has instantaneous transitions between the high and low levels. In practice, this is never achieved because of physical limitations of the system that generates the waveform. The times taken for the signal to rise from the low level to the high level and back again are called the rise time and the fall time respectively.

If the system is overdamped, then the waveform may never actually reach the theoretical high and low levels, and if the system is underdamped, it will oscillate about the high and low levels before settling down. In these cases, the rise and fall times are measured between specified intermediate levels, such as 5% and 95%, or 10% and 90%. The bandwidth of a system is related to the transition times of the waveform; there are formulas allowing one to be determined approximately from the other.

External links

Square Wave Approximated by Sines Interactive demo of square wave synthesis using sine waves.
Flash applets Square wave.

</raw> </toggledisplay>

English Journal

Preparation, characterization of Fe(3)O(4) at TiO(2) magnetic nanoparticles and their application for immunoassay of biomarker of exposure to organophosphorus pesticides.

Zhang X, Wang H, Yang C, Du D, Lin Y.SourceKey Laboratory of Pesticide and Chemical Biology of Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, PR China.
Biosensors & bioelectronics.Biosens Bioelectron.2013 Mar 15;41:669-74. doi: 10.1016/j.bios.2012.09.047. Epub 2012 Oct 12.
Novel Fe(3)O(4) at TiO(2) magnetic nanoparticles were prepared and developed for a new nanoparticle-based immunosensor for electrochemical quantification of organophosphorylated butyrylcholinesterase (BChE) in plasma, a specific biomarker of exposure to organophosphorus (OP) agents. The Fe(3)O(4) at
PMID 23122753

Triazole-acridine conjugates: redox mechanisms and in situ electrochemical evaluation of interaction with double-stranded DNA.

Pontinha AD, Sparapani S, Neidle S, Oliveira-Brett AM.SourceDepartamento de Química, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, 3004-535 Coimbra, Portugal.
Bioelectrochemistry (Amsterdam, Netherlands).Bioelectrochemistry.2013 Feb;89:50-6. doi: 10.1016/j.bioelechem.2012.08.005. Epub 2012 Sep 11.
Redox mechanisms and in situ electrochemical interaction with double-stranded DNA were investigated using a DNA-electrochemical biosensor for two disubstituted triazole-linked acridine compounds (GL15 and GL7), previously reporting as quadruplex DNA-binding molecules. The redox properties of GL15 an
PMID 23059201

Peroxidase immobilized on phospholipid bilayers supported on au (111) by DTT self-assembled monolayers: Application to dopamine determination.

Fritzen-Garcia MB, Zoldan VC, Oliveira IR, Soldi V, Pasa AA, Creczynski-Pasa TB.SourceGEIMM, Departamento de Ciências Farmacêuticas, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil; telephone: 55-48-3721-2212; fax: 55-48-3234-0599; Ciência e Engenharia de Materiais, Universidade Federal de Santa Catarina, Florianópolis, Santa Catarina, Brazil. maurifritzen@hotmail.com.
Biotechnology and bioengineering.Biotechnol Bioeng.2013 Feb;110(2):374-82. doi: 10.1002/bit.24721. Epub 2012 Sep 18.
In this work, horseradish peroxidase (HRP) was immobilized on dimyristoylphosphatidylcholine (DMPC) bilayers supported on Au (111) by dithiotreitol (DTT) self-assembled monolayers and used as a nanostructured electrochemical biosensor to dopamine determination. The morphology of the phospholipid bil
PMID 22949216

Japanese Journal

T_{\text{c}} Enhancement by Aliovalent Anionic Substitution in Superconducting BaTi

Nakano Kousuke,Yajima Takeshi,Takeiri Fumitaka,Green Mark A.,Hester James,Kobayashi Yoji,Kageyama Hiroshi
J Phys Soc Jpn 82(7), 074707-074707-5, 2013-07-15
… BaTi<inf>2</inf>Sb<inf>2</inf>O is a T_{\text{c}}=1.2 K superconductor with a d^{1} square lattice, and isovalent Bi substitution for Sb can increase its T_{\text{c}} to 4.6 K (BaTi<inf>2</inf>Bi<inf>2</inf>O), accompanied by the complete suppression of charge density wave (CDW) or spin density wave (SDW) transition. …
NAID 150000107718

Bifurcation Study of Three-Dimensional Solutions of the Curved Square-Duct Flow

Watanabe Takeshi,Yanase Shinichiro
J Phys Soc Jpn 82(7), 074402-074402-9, 2013-07-15
… Steady, periodic and traveling-wave solutions of the flow through a curved square duct are obtained numerically, and their linear stability to two- and three-dimensional disturbances is investigated. … It is found that a steady traveling-wave (STW) solution bifurcates from the symmetric steady solution branch and is linearly stable in the intermediate range between low and high pressure gradient regions. …
NAID 150000107705

円偏波用3周波共用小型マイクロストリップアンテナ(学生若手発表,学生若手発表および一般)

田中明賢,藤本孝文
映像情報メディア学会技術報告 37(4), 91-94, 2013-01-23
本稿では,方形パッチの各辺に2対のクランク状スリットを装荷した1点給電型円偏波用3周波共用マイクロストリップアンテナを提案している.クランク状スリットの長さおよび位置を調整することにより,3つの周波数および軸比が調整可能であることをシミュレーションにより明らかにしている.また,得られた設計手順によりGPS用3周波数(L1band, L2band, L5band)共用アンテナの設計を行っている.
NAID 110009594601