An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 232 Search : ist
nonexistence
  ناهستومندی، ناهستی   
nâhastumandi, nâhasti

Fr.: non existence   

Math.: The fact that no → solution exists for a given → problem. In mathematics, nonexistence usually is a matter of impossibility.

non-; → existence.

normal distribution
  واباژش ِ هنجارور   
vâbâžeš-e hanjârvar

Fr.: distribution normale   

A theoretical frequency distribution for a set of variable data, usually represented by a bell-shaped curve with a mean at the center of the curve and tail widths proportional to the standard deviation of the data about the mean. Same as → Gaussian distribution.

normal; → distribution.

nuclear statistical equilibrium (NSE)
  ترازمندی ِ آماری ِ هسته‌ای   
tarâzmandi-ye âmâri-ye haste-yi

Fr.: équilibre statistique nucléaire   

In → nucleosynthesis models, the condition in which all nuclear species are in equilibrium under exchange of → protons and → neutrons. Matter in nuclear statistical equilibrium is characterized by a large abundance of iron peak nuclei. In such equilibria abundance of each nuclide can be calculated from repeated application of → Saha equation.

nuclear; → statistical; → equilibrium.

nutritionist
  فارشگر   
fârešgar

Fr.: nutritioniste   

A person who is trained or expert in the science of nutrition.

nutrition; → -ist.

Nyquist formula
  دیسول ِ نیکویءیست   
disul-e Nyquist

Fr.: formule de Nyquist   

The mean square noise voltage across a resistance in thermal equilibrium is four times the product of the resistance, Boltzmann's constant, the absolute temperature, and the frequency range within which the voltage is measured. → Johnson-Nyquist noise.

Named after Harry Nyquist (1889-1976), a Swedish-born American physicist, who made important contributions to information theory. → Johnson-Nyquist noise; → formula.

Nyquist frequency
  بسامد ِ نیکویءیست   
basâmad-e Nyquist

Fr.: fréquence de Nyquist   

The highest frequency that can be determined in a Fourier analysis of a discrete sampling of data.

Nyquist formula; → frequency.

Nyquist-Shannon sampling theorem
  فربین ِ نمونان‌گیری ِ نیکویءیست-شانون   
farbin-e nemunân-giri-ye Nyquist-Shannon

Fr.: théorème d'échantillonnage de Nyquist-Shannon   

The minimum number of resolution elements required to properly sample a signal, such as a star image, without causing erroneous effects known as aliasing. For electronic imaging, this number is generally taken as 2 pixels across the seeing disk diameter at the half intensity points. Also called → Shannon's sampling theorem and → sampling theorem.

Named after Harry Nyquist (1889-1976), a Swedish-born American physicist, who made important contributions to information theory, and Claude Elwood Shannon (1916-2001), an American mathematician and pioneer of information theory; → theorem.

opportunist
  نیکواگرا   
nikvâgerâ

Fr.: opportuniste   

A person who adapts his actions, responses, etc, to take advantage of opportunities, circumstances, etc. (Dictionary.com).

opportune + → -ist.

organic chemistry
  شیمیِ ارگانیک، ~ ِ آلی   
šimi-ye orgânik, ~ âli

Fr.: chimie organique   

The study of compounds that contain carbon chemically bound to hydrogen.

organic; → chemistry.

perfectionist
  فرساختگرا، فرساختگر   
farsâxtgerâ, farsâxtgar

Fr.: perfectioniste   

1) A person who adheres to or believes in → perfectionism.
2) A person who demands perfection of himself, herself, or others (Dictionary.com).

perfection; → -ist.

perihelion distance
  اپست ِ پیراهوری   
apest-e pirâhuri

Fr.: distance au périhélie   

The distance between the → Sun and an → object in orbit around it when they are at their closest approach.

perihelion; → distance.

persist
  پریستادن   
paristâdan

Fr.: persister   

1) To continue steadfastly or firmly in some state, purpose, course of action, or the like, especially in spite of opposition, remonstrance, etc.
2) To last or endure tenaciously (Dictionary.com).

M.Fr. persister, from L. persistere "abide, continue steadfastly," from → per- "thoroughly" + sistere "come to stand, cause to stand still," → resist.

Paristâdan from par-, → per-, + istâdan "to stand," → resist.

persistence
  پریست   
parist

Fr.: persistance   

The act or fact of persisting; the quality of being persistent.

Verbal noun from → persist.

persistent
  پریستنده   
paristandé

Fr.: persistant   

Persisting, especially in spite of opposition, obstacles, discouragement, etc.; persevering (Dictionary.com).

Adjective from → persist.

phlogiston
  فلوژیستون   
fložiston (#)

Fr.: phlogiston   

A hypothetical substance that, prior to the discovery of → oxygen, was thought to be released during → combustion. → phlogiston theory.

From New Latin, from Gk. phlogiston, neuter of phlogistos "inflammable, burnt up," from phlogizein "to set on fire, burn," from phlox "flame, blaze;" from PIE root *bhel- "to shine, burn."

Fložiston, loan from Fr, as above.

phlogiston theory
  نگره‌ی ِ فلوژیستون   
negare-ye fložiston

Fr.: phlogistique   

An obsolete theory of combustion in which all flammable objects were supposed to contain a substance called → phlogiston, which was released when the object burned. The existence of this hypothetical substance was proposed in 1669 by Johann Becher, who called it terra pinguis "fat earth." For example, as wood burns it releases phlogiston into the air, leaving ash behind. Ash was therefore wood minus phlogiston. In the early 18th century Georg Stahl renamed the substance phlogiston. The theory was disproved by Antoine Lavoisier in 1783, who proved the principle of conservation of mass, refuted the phlogiston theory and proposed the oxygen theory of burning.

phlogiston; → theory.

photochemistry
  شید-شیمی، نور-شیمی   
šid-šimi, nur-šimi

Fr.: photochimie   

The study of the chemical and physical changes occurring when a molecule or atom absorbs photons of light.

photo- + → chemistry.

physical chemistry
  شیمی ِ فیزیکی   
šimi-ye fiziki (#)

Fr.: chimie physique   

The branch of chemistry dealing with the relations between the physical properties of substances and their chemical composition and transformations.

physical; → chemistry.

physicist
  فیزیکدان   
fizikdân (#)

Fr.: physicien   

A specialist in → physics.

From physic, → physics, + → -ist.

Fizikdân, from fizik, → physics, + -dân "knower," present stem of dânestan "to know," → science.

pincushion distortion
  چولگی ِ بالشتکی   
cowlegi-ye bâleštaki

Fr.: distorsion en coussinet   

An → aberration of a → lens  → system in which → magnification increases with → distance from the → optical axis, whereby → horizontal and → vertical lines bend inward toward the → center of the → field. Opposite of → barrel distortion.

Pincushion, from pin, from M.E. pinne, O.E. pinn "peg;" cf. D. pin, Ger. Pinne; perhaps from L. pinna "feather, quill" + cushion, M.E. cuisshin, O.Fr. coissin (Fr. coussin) a variant of V.L. *coxinum, either from L. coxa "hip, thigh," or from L. culcita "mattress;" → distortion.

Cowlegi, → distortion; bâleštaki, adj. of bâleštak, diminutive of bâlešt, variant bâleš "cushion, pillow," Mid.Pers. bâlišn, bâlên "cushion, pillow;" Av. barəiš- "pillow, cushion;" cf. Skt. barhis- "straw, a bed or layer of kusa grass strewed over the sacrificial ground."


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