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Evaluation of machine translation-Round-trip translation-While round-trip translation may be useful to generate a "surplus of fun," the methodology is deficient for serious study of machine translation quality. | milkshake721/2.1M-wiki-STEM |
Evaluation of machine translation-Human evaluation-This section covers two of the large scale evaluation studies that have had significant impact on the field—the ALPAC 1966 study and the ARPA study. | milkshake721/2.1M-wiki-STEM |
Evaluation of machine translation-Human evaluation-Automatic Language Processing Advisory Committee (ALPAC) One of the constituent parts of the ALPAC report was a study comparing different levels of human translation with machine translation output, using human subjects as judges. The human judges were specially traine... | milkshake721/2.1M-wiki-STEM |
Evaluation of machine translation-Human evaluation-The variables studied were "intelligibility" and "fidelity". Intelligibility was a measure of how "understandable" the sentence was, and was measured on a scale of 1–9. Fidelity was a measure of how much information the translated sentence retained compared to the orig... | milkshake721/2.1M-wiki-STEM |
Evaluation of machine translation-Human evaluation-The study showed that the variables were highly correlated when the human judgment was averaged per sentence. The variation among raters was small, but the researchers recommended that at the very least, three or four raters should be used. The evaluation methodology m... | milkshake721/2.1M-wiki-STEM |
Evaluation of machine translation-Human evaluation-Advanced Research Projects Agency (ARPA) As part of the Human Language Technologies Program, the Advanced Research Projects Agency (ARPA) created a methodology to evaluate machine translation systems, and continues to perform evaluations based on this methodology. The ... | milkshake721/2.1M-wiki-STEM |
Evaluation of machine translation-Human evaluation-The evaluation programme involved testing several systems based on different theoretical approaches; statistical, rule-based and human-assisted. A number of methods for the evaluation of the output from these systems were tested in 1992 and the most recent suitable met... | milkshake721/2.1M-wiki-STEM |
Evaluation of machine translation-Human evaluation-Comprehension evaluation aimed to directly compare systems based on the results from multiple choice comprehension tests, as in Church et al. (1993). The texts chosen were a set of articles in English on the subject of financial news. These articles were translated by ... | milkshake721/2.1M-wiki-STEM |
Evaluation of machine translation-Human evaluation-The idea of quality panel evaluation was to submit translations to a panel of expert native English speakers who were professional translators and get them to evaluate them. The evaluations were done on the basis of a metric, modelled on a standard US government metric... | milkshake721/2.1M-wiki-STEM |
Evaluation of machine translation-Human evaluation-Along with a modified form of the comprehension evaluation (re-styled as informativeness evaluation), the most popular method was to obtain ratings from monolingual judges for segments of a document. The judges were presented with a segment, and asked to rate it for tw... | milkshake721/2.1M-wiki-STEM |
Evaluation of machine translation-Human evaluation-Measuring systems based on adequacy and fluency, along with informativeness is now the standard methodology for the ARPA evaluation program. | milkshake721/2.1M-wiki-STEM |
Evaluation of machine translation-Automatic evaluation-In the context of this article, a metric is a measurement. A metric that evaluates machine translation output represents the quality of the output. The quality of a translation is inherently subjective, there is no objective or quantifiable "good." Therefore, any m... | milkshake721/2.1M-wiki-STEM |
Evaluation of machine translation-Automatic evaluation-The measure of evaluation for metrics is correlation with human judgment. This is generally done at two levels, at the sentence level, where scores are calculated by the metric for a set of translated sentences, and then correlated against human judgment for the sa... | milkshake721/2.1M-wiki-STEM |
Evaluation of machine translation-Automatic evaluation-While not widely reported, it has been noted that the genre, or domain, of a text has an effect on the correlation obtained when using metrics. Coughlin (2003) reports that comparing the candidate text against a single reference translation does not adversely affec... | milkshake721/2.1M-wiki-STEM |
Evaluation of machine translation-Automatic evaluation-Even if a metric correlates well with human judgment in one study on one corpus, this successful correlation may not carry over to another corpus. Good metric performance, across text types or domains, is important for the reusability of the metric. A metric that o... | milkshake721/2.1M-wiki-STEM |
Evaluation of machine translation-Automatic evaluation-Another important factor in the usefulness of an evaluation metric is to have a good correlation, even when working with small amounts of data, that is candidate sentences and reference translations. Turian et al. (2003) point out that, "Any MT evaluation measure i... | milkshake721/2.1M-wiki-STEM |
Evaluation of machine translation-Automatic evaluation-The aim of this subsection is to give an overview of the state of the art in automatic metrics for evaluating machine translation. | milkshake721/2.1M-wiki-STEM |
Evaluation of machine translation-Automatic evaluation-BLEU BLEU was one of the first metrics to report a high correlation with human judgments of quality. The metric is currently one of the most popular in the field. The central idea behind the metric is that "the closer a machine translation is to a professional huma... | milkshake721/2.1M-wiki-STEM |
Evaluation of machine translation-Automatic evaluation-NIST The NIST metric is based on the BLEU metric, but with some alterations. Where BLEU simply calculates n-gram precision adding equal weight to each one, NIST also calculates how informative a particular n-gram is. That is to say, when a correct n-gram is found, ... | milkshake721/2.1M-wiki-STEM |
Evaluation of machine translation-Automatic evaluation-Word error rate The Word error rate (WER) is a metric based on the Levenshtein distance, where the Levenshtein distance works at the character level, WER works at the word level. It was originally used for measuring the performance of speech recognition systems but... | milkshake721/2.1M-wiki-STEM |
Evaluation of machine translation-Automatic evaluation-A related metric is the Position-independent word error rate (PER), which allows for the re-ordering of words and sequences of words between a translated text and a reference translation. | milkshake721/2.1M-wiki-STEM |
Evaluation of machine translation-Automatic evaluation-METEOR The METEOR metric is designed to address some of the deficiencies inherent in the BLEU metric. The metric is based on the weighted harmonic mean of unigram precision and unigram recall. The metric was designed after research by Lavie (2004) into the signific... | milkshake721/2.1M-wiki-STEM |
Evaluation of machine translation-Automatic evaluation-LEPOR A new MT evaluation metric LEPOR was proposed as the combination of many evaluation factors including existing ones (precision, recall) and modified ones (sentence-length penalty and n-gram based word order penalty). The experiments were tested on eight langu... | milkshake721/2.1M-wiki-STEM |
Evaluation of machine translation-Overviews on Human and Automatic Evaluation Methodologies-There are some machine translation evaluation survey works, where people introduced more details about what kinds of human evaluation methods they used and how they work, such as the intelligibility, fidelity, fluency, adequacy,... | milkshake721/2.1M-wiki-STEM |
Evaluation of machine translation-Software for Automated Evaluation-Asia Online Language Studio - Supports BLEU, TER, F-Measure, METEOR BLEU F-Measure NIST METEOR TER TERP LEPOR hLEPOR KantanAnalytics - segment level MT quality estimation | milkshake721/2.1M-wiki-STEM |
Index mineral-Index mineral-An index mineral is used in geology to determine the degree of metamorphism a rock has experienced. Depending on the original composition of and the pressure and temperature experienced by the protolith (parent rock), chemical reactions between minerals in the solid state produce new mineral... | milkshake721/2.1M-wiki-STEM |
Index mineral-Index mineral-The concept traces its roots to 1912, when G. M. Barrow mapped zones of metamorphism in southern Scotland. Each zone is named for the index mineral that appears in it. E.g. the chlorite zone is named for chlorite. | milkshake721/2.1M-wiki-STEM |
Index mineral-Mineralogic zones-Mudrock, a fine-grained sedimentary rock often containing aluminium-rich minerals, produces these minerals after being metamorphosed, from low to high grade: Chlorite zone: quartz, chlorite, muscovite, albite Biotite zone: quartz, muscovite, biotite, chlorite, albite Garnet zone: quartz,... | milkshake721/2.1M-wiki-STEM |
Bathometer-Bathometer-A bathometer (also bathymeter) is an instrument for measuring water depth. It was previously used mainly in oceanographical studies, but is rarely employed nowadays. The term originates from Greek βαθύς (bathys), "deep" and μέτρον (métron), "measure". | milkshake721/2.1M-wiki-STEM |
Bathometer-History-The earliest idea for a bathometer is due to Leon Battista Alberti (1404–1472) who sunk a hollow sphere attached to some ballast with a hook. When the ball reached the bottom it detached from the ballast and resurfaced. The depth was determined (rather inaccurately) by the time it took to surface. Ja... | milkshake721/2.1M-wiki-STEM |
Harrison-Meldola Memorial Prizes-Harrison-Meldola Memorial Prizes-The Harrison-Meldola Memorial Prizes are annual prizes awarded by Royal Society of Chemistry to chemists in Britain who are 34 years of age or below. The prize is given to scientist who demonstrate the most meritorious and promising original investigati... | milkshake721/2.1M-wiki-STEM |
Harrison-Meldola Memorial Prizes-Harrison-Meldola Memorial Prizes-They were begun in 2008 when two previous awards, the Meldola Medal and Prize and the Edward Harrison Memorial Prize, were joined together. They commemorate Raphael Meldola and Edward Harrison. | milkshake721/2.1M-wiki-STEM |
Harrison-Meldola Memorial Prizes-Winners of the Harrison-Meldola Memorial Prizes-Source: Royal Society of Chemistry 2022 Volker Deringer, University of Oxford Marina Freitag, Newcastle University Paul McGonigal, Durham University 2021 Nicholas Chilton, University of Manchester Fernanda Duarte, University of Oxford Ceri... | milkshake721/2.1M-wiki-STEM |
Harrison-Meldola Memorial Prizes-Previous winners of the Meldola Medal and Prize-The Meldola Medal and Prize commemorated Raphael Meldola, President of the Maccabaeans and the Institute of Chemistry. The last winners of the prize in 2007 were Hon Lam from the University of Edinburgh, and Rachel O'Reilly of the Universi... | milkshake721/2.1M-wiki-STEM |
Harrison-Meldola Memorial Prizes-Previous winners of the Edward Harrison Memorial Prize-The Edward Harrison Memorial Prize commemorated the work of Edward Harrison who was credited with producing the first serviceable gas mask. The last winner of the prize was Katherine Holt of University College London. | milkshake721/2.1M-wiki-STEM |
Alder carr-Alder carr-An alder carr is a particular type of carr, i.e. waterlogged wooded terrain populated with alder trees. | milkshake721/2.1M-wiki-STEM |
Alder carr-Examples-Alder Carr, Hildersham Alderfen Broad Fawley Ford on the Beaulieu River Biebrza National Park Fen Alder Carr Harston Wood Holywells Park, Ipswich: Pond 5 is known as Alder Carr and is a biodiversity action plan habitat. Historically there was another Alder Carr in the Cobbold family estate in what i... | milkshake721/2.1M-wiki-STEM |
Seismic intensity scales-Seismic intensity scales-Seismic intensity scales categorize the intensity or severity of ground shaking (quaking) at a given location, such as resulting from an earthquake. They are distinguished from seismic magnitude scales, which measure the magnitude or overall strength of an earthquake, w... | milkshake721/2.1M-wiki-STEM |
Seismic intensity scales-Seismic intensity scales-Intensity scales are based on the observed effects of the shaking, such as the degree to which people or animals were alarmed, and the extent and severity of damage to different kinds of structures or natural features. The maximal intensity observed, and the extent of t... | milkshake721/2.1M-wiki-STEM |
Seismic intensity scales-Ground shaking-Ground shaking can be caused in various ways (volcanic tremors, avalanches, large explosions, etc.), but shaking intense enough to cause damage is usually due to rupturing of the earth's crust known as earthquakes. The intensity of shaking depends on several factors: The "size" ... | milkshake721/2.1M-wiki-STEM |
Seismic intensity scales-Ground shaking-Where an earthquake is not recorded on seismographs an isoseismal map showing the intensities felt at different areas can be used to estimate the location and magnitude of the quake. Such maps are also useful for estimating the shaking intensity, and thereby the likely level of d... | milkshake721/2.1M-wiki-STEM |
Seismic intensity scales-History-The first simple classification of earthquake intensity was devised by Domenico Pignataro in the 1780s. The first recognisable intensity scale in the modern sense of the word was drawn up by P.N.G. Egen in 1828. However, the first modern mapping of earthquake intensity was made by Rober... | milkshake721/2.1M-wiki-STEM |
5Beta-Scymnol-5Beta-Scymnol-5Beta-Scymnol, also known simply as scymnol, is a synthetic INCI-listed skin conditioning ingredient. The molecule is a steroid derivative that behaves as a hydroxyl radical scavenger and is used for the treatment of skin blemishes such as blocked pores and acne. | milkshake721/2.1M-wiki-STEM |
5Beta-Scymnol-History-The molecule was identified and isolated from shark tissues by Professor Takuo Kosuge, Shizuoka College of Pharmacy, Shizuoka, Japan during the 1980s. Based on usage as a traditional folk remedy, it was hypothesised the ingredient may be effective for the treatment of scalds, blemishes and acne. | milkshake721/2.1M-wiki-STEM |
5Beta-Scymnol-Traits-5Beta-Scymnol is a hydroxyl (OH) free radical scavenger. Scymnol's role in quenching free radicals may play a role in inhibiting acne. | milkshake721/2.1M-wiki-STEM |
Lighttpd-Lighttpd-lighttpd (prescribed pronunciation: "lighty") is an open-source web server optimized for speed-critical environments while remaining standards-compliant, secure and flexible. It was originally written by Jan Kneschke as a proof-of-concept of the c10k problem – how to handle 10,000 connections in paral... | milkshake721/2.1M-wiki-STEM |
Lighttpd-Premise-The low memory footprint (compared to other web servers), small CPU load and speed optimizations make lighttpd suitable for servers that are suffering load problems, or for serving static media separately from dynamic content. lighttpd is free and open-source software and is distributed under the BSD l... | milkshake721/2.1M-wiki-STEM |
Lighttpd-Application support-lighttpd supports the FastCGI, SCGI and CGI interfaces to external programs, allowing web applications written in any programming language to be used with the server. As a particularly popular language, PHP performance has received special attention. Lighttpd's FastCGI can be configured to ... | milkshake721/2.1M-wiki-STEM |
Lighttpd-Features-Load balancing, CGI, FastCGI, SCGI, HTTP proxy, Servlet AJP, WebSocket tunnel support chroot support Web server event mechanism performance – select(), poll(), and epoll() Support for more efficient event notification schemes like kqueue and epoll Conditional URL rewriting (mod_rewrite) TLS/SSL with S... | milkshake721/2.1M-wiki-STEM |
Lighttpd-Features-Authentication against an LDAP or DBI server RRDtool statistics Rule-based downloading with possibility of a script handling only authentication Server Side Includes support (but not server-side CGI from SSI) Flexible virtual hosting Modules support Lua programming language scripts via mod_magnet WebD... | milkshake721/2.1M-wiki-STEM |
Lighttpd-Features-HTTP/2 support since lighttpd 1.4.56 HTTP/2 WebSocket support since lighttpd 1.4.65 | milkshake721/2.1M-wiki-STEM |
Lighttpd-Limitations-Versions below 1.4.40 do not officially support sending large files from CGI, FastCGI, or proxies unless X-Sendfile is used. This limitation has been removed in lighttpd 1.4.40.
No HTTP/3 support | milkshake721/2.1M-wiki-STEM |
Lighttpd-Usage-Lighttpd was used in the past by several high-traffic websites, including Bloglines, xkcd, Meebo, and YouTube. The Wikimedia Foundation also once ran Lighttpd servers.
Due to relatively small size it's often used in embedded devices like GL.iNet and Turris Omnia.
It's also used by git as a HTTP server da... | milkshake721/2.1M-wiki-STEM |
Imidazolidinyl urea-Imidazolidinyl urea-Imidazolidinyl urea is an antimicrobial preservative used in cosmetics. It is chemically related to diazolidinyl urea which is used in the same way. Imidazolidinyl urea acts as a formaldehyde releaser. | milkshake721/2.1M-wiki-STEM |
Imidazolidinyl urea-Safety-Some people have a contact allergy to imidazolidinyl urea causing dermatitis. Such people are often also allergic to diazolidinyl urea. | milkshake721/2.1M-wiki-STEM |
Imidazolidinyl urea-Chemistry-Imidazolidinyl urea was poorly characterized until recently and the single Chemical Abstracts Service structure assigned to it is probably not the major one in the commercial material. Instead, new data indicate that the hydroxymethyl functional group of each imidazolidine ring is attached... | milkshake721/2.1M-wiki-STEM |
VER-3323-VER-3323-VER-3323 is a drug which acts as a selective agonist for both the 5-HT2B and 5-HT2C serotonin receptor subtypes, with moderate selectivity for 5-HT2C, but relatively low affinity for 5-HT2A. It has potent anorectic effects in animal studies. | milkshake721/2.1M-wiki-STEM |
Lanthanum hexaboride-Lanthanum hexaboride-Lanthanum hexaboride (LaB6, also called lanthanum boride and LaB) is an inorganic chemical, a boride of lanthanum. It is a refractory ceramic material that has a melting point of 2210 °C, and is insoluble in water and hydrochloric acid. It is extremely hard, with a Mohs hardnes... | milkshake721/2.1M-wiki-STEM |
Lanthanum hexaboride-Uses-The principal use of lanthanum hexaboride is in hot cathodes, either as a single crystal or as a coating deposited by physical vapor deposition. Hexaborides, such as lanthanum hexaboride (LaB6) and cerium hexaboride (CeB6), have low work functions, around 2.5 eV. They are also somewhat resista... | milkshake721/2.1M-wiki-STEM |
Bunt (sail)-Bunt (sail)-The bunt of a sail is the middle part of it, which is purposely formed into a kind of curved bag, or cavity, so that the sail might receive more wind. It is chiefly used in topsails, for courses are for the most part cut square, or at least with a small allowance, for bunt or compass.
Sailors wo... | milkshake721/2.1M-wiki-STEM |
Goulac-Goulac-Goulac, also known as Glutrin, is a core binder developed from wood pulping. It is made from lignin pitch.The material has a dark colour and is soluble in water.Goulac water was used to make Gallagher sharp sand. It was trademarked in the 1940s. It prevents a chemical reaction between lead arsenate and li... | milkshake721/2.1M-wiki-STEM |
Logical matrix-Logical matrix-A logical matrix, binary matrix, relation matrix, Boolean matrix, or (0, 1)-matrix is a matrix with entries from the Boolean domain B = {0, 1}. Such a matrix can be used to represent a binary relation between a pair of finite sets. It is an important tool in combinatorial mathematics and t... | milkshake721/2.1M-wiki-STEM |
Logical matrix-Matrix representation of a relation-If R is a binary relation between the finite indexed sets X and Y (so R ⊆ X ×Y ), then R can be represented by the logical matrix M whose row and column indices index the elements of X and Y, respectively, such that the entries of M are defined by mi,j={1(xi,yj)∈R,0(xi... | milkshake721/2.1M-wiki-STEM |
Logical matrix-Matrix representation of a relation-Example The binary relation R on the set {1, 2, 3, 4} is defined so that aRb holds if and only if a divides b evenly, with no remainder. For example, 2R4 holds because 2 divides 4 without leaving a remainder, but 3R4 does not hold because when 3 divides 4, there is a r... | milkshake721/2.1M-wiki-STEM |
Logical matrix-Other examples-A permutation matrix is a (0, 1)-matrix, all of whose columns and rows each have exactly one nonzero element.
A Costas array is a special case of a permutation matrix.
An incidence matrix in combinatorics and finite geometry has ones to indicate incidence between points (or vertices) and l... | milkshake721/2.1M-wiki-STEM |
Logical matrix-Some properties-The matrix representation of the equality relation on a finite set is the identity matrix I, that is, the matrix whose entries on the diagonal are all 1, while the others are all 0. More generally, if relation R satisfies I ⊆ R, then R is a reflexive relation.
If the Boolean domain is vie... | milkshake721/2.1M-wiki-STEM |
Logical matrix-Lattice-Let n and m be given and let U denote the set of all logical m × n matrices. Then U has a partial order given by when 1.
In fact, U forms a Boolean algebra with the operations and & or between two matrices applied component-wise. The complement of a logical matrix is obtained by swapping all zero... | milkshake721/2.1M-wiki-STEM |
Logical matrix-Logical vectors-If m or n equals one, then the m × n logical matrix (mij) is a logical vector or bit string. If m = 1, the vector is a row vector, and if n = 1, it is a column vector. In either case the index equaling 1 is dropped from denotation of the vector.
Suppose (Pi),i=1,2,…,m and (Qj),j=1,2,…,n... | milkshake721/2.1M-wiki-STEM |
Logical matrix-Logical vectors-A reordering of the rows and columns of such a matrix can assemble all the ones into a rectangular part of the matrix.Let h be the vector of all ones. Then if v is an arbitrary logical vector, the relation R = v hT has constant rows determined by v. In the calculus of relations such an R ... | milkshake721/2.1M-wiki-STEM |
Logical matrix-Logical vectors-Consider the table of group-like structures, where "unneeded" can be denoted 0, and "required" denoted by 1, forming a logical matrix R. | milkshake721/2.1M-wiki-STEM |
Logical matrix-Logical vectors-To calculate elements of RRT , it is necessary to use the logical inner product of pairs of logical vectors in rows of this matrix. If this inner product is 0, then the rows are orthogonal. In fact, small category is orthogonal to quasigroup, and groupoid is orthogonal to magma. Conseque... | milkshake721/2.1M-wiki-STEM |
Logical matrix-Row and column sums-Adding up all the ones in a logical matrix may be accomplished in two ways: first summing the rows or first summing the columns. When the row sums are added, the sum is the same as when the column sums are added. In incidence geometry, the matrix is interpreted as an incidence matrix ... | milkshake721/2.1M-wiki-STEM |
H&E stain-H&E stain-Hematoxylin and eosin stain (or haematoxylin and eosin stain or hematoxylin-eosin stain; often abbreviated as H&E stain or HE stain) is one of the principal tissue stains used in histology. It is the most widely used stain in medical diagnosis and is often the gold standard. For example, whe... | milkshake721/2.1M-wiki-STEM |
H&E stain-H&E stain-H&E is the combination of two histological stains: hematoxylin and eosin. The hematoxylin stains cell nuclei a purplish blue, and eosin stains the extracellular matrix and cytoplasm pink, with other structures taking on different shades, hues, and combinations of these colors. Hence a pathol... | milkshake721/2.1M-wiki-STEM |
H&E stain-H&E stain-This stain combination was first introduced in 1877 by chemist N. Wissozky at the Kasan Imperial University in Russia. | milkshake721/2.1M-wiki-STEM |
H&E stain-Uses-The H&E staining procedure is the principal stain in histology in part because it can be done quickly, is not expensive, and stains tissues in such a way that a considerable amount of microscopic anatomy is revealed, and can be used to diagnose a wide range of histopathologic conditions. The results ... | milkshake721/2.1M-wiki-STEM |
H&E stain-Method of application-There are many ways to prepare the hematoxylin solutions (formulation) used in the H&E procedure, in addition, there are many laboratory protocols for producing H&E stained slides, some of which may be specific to a certain laboratory. Although there is no standard procedure, the res... | milkshake721/2.1M-wiki-STEM |
H&E stain-Results-Hematoxylin principally colors the nuclei of cells blue or dark-purple, along with a few other tissues, such as keratohyalin granules and calcified material. Eosin stains the cytoplasm and some other structures including extracellular matrix such as collagen in up to five shades of pink. The eosin... | milkshake721/2.1M-wiki-STEM |
H&E stain-Mode of action-Although hematein, an oxidized form of hematoxylin, is the active colorant (when combined with a mordant), the stain is still referred to as hematoxylin. Hematoxylin, when combined with a mordant (most commonly aluminum alum) is often considered to "resemble" a basic, positively charged, or... | milkshake721/2.1M-wiki-STEM |
Trichloroacetic acid-Trichloroacetic acid-Trichloroacetic acid (TCA; TCAA; also known as trichloroethanoic acid) is an analogue of acetic acid in which the three hydrogen atoms of the methyl group have all been replaced by chlorine atoms. Salts and esters of trichloroacetic acid are called trichloroacetates. | milkshake721/2.1M-wiki-STEM |
Trichloroacetic acid-Synthesis-It is prepared by the reaction of chlorine with acetic acid in the presence of a suitable catalyst such as red phosphorus. This reaction is Hell–Volhard–Zelinsky halogenation.
CH3COOH + 3 Cl2 → CCl3COOH + 3 HClAnother route to trichloroacetic acid is the oxidation of trichloroacetaldehyde... | milkshake721/2.1M-wiki-STEM |
Trichloroacetic acid-Use-It is widely used in biochemistry for the precipitation of macromolecules, such as proteins, DNA, and RNA. TCA and DCA are both used in cosmetic treatments (such as chemical peels and tattoo removal) and as topical medication for chemoablation of warts, including genital warts. It can kill norm... | milkshake721/2.1M-wiki-STEM |
Trichloroacetic acid-Use-The sodium salt (sodium trichloroacetate) was used as an herbicide starting in the 1950s but regulators removed it from the market in the late 1980s and early 1990s. | milkshake721/2.1M-wiki-STEM |
Trichloroacetic acid-Environmental and health concerns-According to the European Chemicals Agency, "This substance causes severe skin burns and eye damage, is very toxic to aquatic life and has long lasting toxic effects."Trichloroacetic acid was placed on the California Proposition 65 List in 2013 "as a chemical known... | milkshake721/2.1M-wiki-STEM |
Trichloroacetic acid-History-The discovery of trichloroacetic acid by Jean-Baptiste Dumas in 1839 delivered a striking example to the slowly evolving theory of organic radicals and valences. The theory was contrary to the beliefs of Jöns Jakob Berzelius, starting a long dispute between Dumas and Berzelius. | milkshake721/2.1M-wiki-STEM |
Trichloroacetic acid-Popular culture-In the 1958 film The Blob, a bottle of trichloroacetic acid is tossed at the Blob in a futile attempt to fend it off. | milkshake721/2.1M-wiki-STEM |
Tantalum diselenide-Tantalum diselenide-Tantalum diselenide is a compound made with tantalum and selenium atoms, with chemical formula TaSe2, which belongs to the family of transition metal dichalcogenides. In contrast to molybdenum disulfide (MoS2) or rhenium disulfide (ReS2, tantalum diselenide does not occur spontan... | milkshake721/2.1M-wiki-STEM |
Tantalum diselenide-Tantalum diselenide-In the 2010s, interest in this compound has risen due to its ability to show a charge density wave (CDW), which depends on the crystal structure, up to 600 K, while other transition metal dichalcogenides normally need to be cooled down to hundreds of kelvin degrees, or even below... | milkshake721/2.1M-wiki-STEM |
Tantalum diselenide-Structure-As other TMDs, TaSe2 is a layered compound, with a central tantalum hexagonal lattice sandwiched between two layers of selenium atoms, still with a hexagonal structure. Differently with respect to other 2D materials such as graphene, which is atomically thin, TMDs are composed by trilayers... | milkshake721/2.1M-wiki-STEM |
Tantalum diselenide-Structure-The most studied crystal structures of TaSe2 are the 1T and 2H phases that feature, respectively, octahedral and trigonal prismatic symmetries. However, it is also possible to synthesize the 3R phase or the 1H phase.
1T Phase In the 1T phase, selenium atoms show an octahedral symmetry and ... | milkshake721/2.1M-wiki-STEM |
Tantalum diselenide-Structure-Depending on the temperature, it shows different types of charge density waves (CDW): an incommensurate CDW (ICDW) between 600 K and 473 K and a commensurate CDW (CCDW) below 473 K. In the commensurate CDW, the resulting superlattice shows a 13 13 reconstruction often addressed as star of... | milkshake721/2.1M-wiki-STEM |
Tantalum diselenide-Structure-2H Phase The 2H phase is based on a configuration of selenium atoms characterized by a trigonal prismatic symmetry and an equal relative orientation in the topmost and bottommost layers. The lattice parameters are a = b = 3.43 Å, while c = 1.27 nm. Depending on the temperature, it shows di... | milkshake721/2.1M-wiki-STEM |
Tantalum diselenide-Structure-In the 2H phase the single trilayers are stacked one opposed to others, as shown in the relative image. Through molecular beam epitaxy it is possible to grow one single trilayer of 2H TaSe2, also known as 1H phase. Basically, the 2H phase can be seen as the stacking of 1H phase with oppose... | milkshake721/2.1M-wiki-STEM |
Tantalum diselenide-Properties-Electric and Magnetic TaSe2 exhibits different properties according to the polytype (2H or 1T), even if the chemical composition remains unchanged. | milkshake721/2.1M-wiki-STEM |
Tantalum diselenide-Properties-1T phase The resistivity at low temperature is similar to that of a metal, but it starts decreasing at higher temperatures. A peak is exhibited at approximately 473 K, which resembles the behavior of semiconductors. 1T phase has almost two orders of magnitude higher resistivity than to th... | milkshake721/2.1M-wiki-STEM |
Tantalum diselenide-Properties-2H phase Resistivity linearly depends on the temperature when the latter exceeds 110 K. On the opposite, below this threshold it shows a non-linear behaviour. This abrupt variation of R(T) at 110 K might be related to the formation of some kinds of magnetic ordering in TaSe2: ordered spin... | milkshake721/2.1M-wiki-STEM |
Tantalum diselenide-Properties-The magnetic susceptibility of the 2H polytype slightly depends on the temperature and peaks in the range 110-120 K. The trend is linearly ascending or descending below and above 110 K, respectively. This maximum in the 2H phases is related to the formation of the CCDW at 120 K. The 2H ph... | milkshake721/2.1M-wiki-STEM |
Tantalum diselenide-Properties-Optical Investigating the non-linear refractive index of tantalum diselenide can be pursued preparing atomically thin flakes of TaSe2 with the liquid phase exfoliation method. Since this technique requires using alcohol, the refractive index of tantalum diselenide can be retrieved through... | milkshake721/2.1M-wiki-STEM |
Tantalum diselenide-Properties-Lubricant Opposite to MoS2, which is largely employed as a lubricant in many different mechanical application, TaSe2 has not shown the same properties, with an average friction coefficient of 0.15. Under friction tests, like the Barker pendulum, it shows an initial friction coefficient of... | milkshake721/2.1M-wiki-STEM |
Tantalum diselenide-Synthesis-There are different methods in order to synthesize tantalum diselenide: depending on the growth parameter, different types of polytype can be stabilized. | milkshake721/2.1M-wiki-STEM |
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