cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Additional file 22 of A cis-regulatory element promoting increased transcription at low temperature in cultured ectothermic Drosophila cells
Creators: name: Bai, Yu
name: Caussinus, Emmanuel
name: Leo, Stefano
name: Bosshardt, Fritz
name: Myachina, Faina
name: Rot, Gregor
name: Robinson, Mark D.
name: Lehner, Christian F.
Publisher: name: figshare
Year: 2021
Subjects: subject: Genetics
subject: FOS: Biological sciences

description: Additional file 22: Fig. S13. Depletion efficiency and effect on endogenous pst transcript levels. (A,B) The indicated dsRNAs were used for RNAi with SR9rg > pst_E1n (mRuby−, GFP+) cells. Two dsRNA preparations (1 or 2) generated from distinct amplicons were used for some targets. The number of independent experiments is indicated in brackets. In addition, lacZ dsRNA was used in parallel for control. Bars represent average transcript levels as determined by qRT-PCR relative to those detected after lacZ depletion, which were set to 1. Whiskers indicate s.d. in case of multiple independent experiments. (A) To assess RNAi efficiency, total RNA was isolated after four days of depletion at 25 °C followed by analysis of the target transcript levels. The target analyzed in case of double depletion is indicated at the bottom. (B) The levels of transcripts derived from the endogenous pst gene were analyzed.
SpotCheck: On-Device Anomaly Detection for Android
Creators: name: Vella, Mark
name: Colombo, Christian
Publisher: name: arXiv
Year: 2021
Subjects: subject: Cryptography and Security (cs.CR)
subject: FOS: Computer and information sciences

description: In recent years the PC has been replaced by mobile devices for many security sensitive operations, both from a privacy and a financial standpoint. While security mechanisms are deployed at various levels, these are frequently put under strain by previously unseen malware. An additional protection layer capable of novelty detection is therefore needed. In this work we propose SpotCheck, an anomaly detector intended to run on Android devices. It samples app executions and submits suspicious apps to more thorough processing by malware sandboxes. We compare Kernel Principal Component Analysis (KPCA) and Variational Autoencoders (VAE) on app execution representations based on the well-known system call traces, as well as a novel approach based on memory dumps. Results show that when using VAE, SpotCheck attains a level of effectiveness comparable to what has been previously achieved for network anomaly detection. Interestingly this is also true for the memory dump approach, relinquishing the need for continuous app monitoring.
Observation of Classical Rotational Inertia and Nonclassical Supersolid Signals in Solid 4He below 250 mK
Creators: name: Rittner, Ann Sophie C.
name: Reppy, John D.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We have confirmed the existence, as first reported by Kim and Chan, of a supersolid state in solid 4He at temperatures below 250 mK. We have employed a torsional oscillator cell with a square cross section to insure a locking of the solid to the oscillating cell. We find that NCRI signal is not a universal property of solid 4He, but can be eliminated through an annealing of the solid helium sample. This result has important implications for the nature of the supersolid state.
Cameron-Liebler k-sets in subspaces and non-existence conditions
Creators: name: De Beule, Jan
name: Mannaert, Jonathan
name: Storme, Leo
Publisher: name: arXiv
Year: 2021
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics

description: In this article we generalize the concepts that were used in the PhD thesis of Drudge to classify Cameron-Liebler line classes in PG$(n,q), n\geq 3$, to Cameron-Liebler sets of $k$-spaces in PG$(n,q)$ and AG$(n,q)$. In his PhD thesis, Drudge proved that every Cameron-Liebler line class in PG$(n,q)$ intersects every $3$-dimensional subspace in a Cameron-Liebler line class in that subspace. We are using the generalization of this result for sets of $k$-spaces in PG$(n,q)$ and AG$(n,q)$. Together with a basic counting argument this gives a very strong non-existence condition, $n\geq 3k+3$. This condition can also be improved for $k$-sets in AG$(n,q)$, with $n\geq 2k+2$.
Grammatical elicitation: Complementation
Creators: name: Kipkoech, Linus
name: Bossi, Madeline
Publisher: name: California Language Archive, University of California, Berkeley
Year: 2022
Subjects: subject: sgc

description: One .mp4 file and one .pdf file. Elicitation of complementation strategies found with emotive factive verbs. Exploration of raising to object with 'want'.
On the Non-Lorentz Invariance of M.W. Evans O(3)-Symmetry Law
Creators: name: Bruhn, Gerhard W
Publisher: name: arXiv
Year: 2006
Subjects: subject: General Physics (physics.gen-ph)
subject: FOS: Physical sciences

description: Correcting a former proof of M.W. Evans it is shown that his O(3) hypothesis is not Lorentz invariant and hence no law of Physics.
description: 5 pages
รูปแบบการขนส่งทางถนนที่เหมาะสมสำหรับการกระจายพัสดุสายพลาธิการของกองทัพอากาศ
Creators: name: ณัฐพร คำพวง
Publisher: name: สถาบันวิจัยและพัฒนา มหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี
Year: 2019
Subjects: รูปแบบการขนส่ง
พัสดุสายพลาธิการ
ต้นทุนการขนส่ง
ระบบสารสนเทศภูมิศาสตร์ (GIS)

description: วารสารวิจัยมหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี, 18, 2, 18-31
การทดสอบและประเมินผลเครื่องสีข้าวตามมาตรฐานผลิตภัณฑ์อุตสาหกรรม
Creators: name: รุ่งเรือง กาลศิริศิลป์
Publisher: name: สถาบันวิจัยและพัฒนา มหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี
Year: 2019
Subjects: โรงสีข้าว
เครื่องกะเทาะข้าวเปลือก
ประสิทธิภาพการสีข้าว
ประสิทธิผลของการสีข้าว

description: วารสารวิจัยมหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี, 18, 2, 1 - 17
Emergence of time-horizon invariant correlation structure in financial returns by subtraction of the market mode
Creators: name: Borghesi, Christian
name: Marsili, Matteo
name: Miccichè, Salvatore
Publisher: name: arXiv
Year: 2007
Subjects: subject: Physics and Society (physics.soc-ph)
subject: Statistical Finance (q-fin.ST)
subject: FOS: Physical sciences
subject: FOS: Economics and business

description: We investigate the emergence of a structure in the correlation matrix of assets' returns as the time-horizon over which returns are computed increases from the minutes to the daily scale. We analyze data from different stock markets (New York, Paris, London, Milano) and with different methods. Result crucially depends on whether the data is restricted to the ``internal'' dynamics of the market, where the ``center of mass'' motion (the market mode) is removed or not. If the market mode is not removed, we find that the structure emerges, as the time-horizon increases, from splitting a single large cluster. In NYSE we find that when the market mode is removed, the structure of correlation at the daily scale is already well defined at the 5 minutes time-horizon, and this structure accounts for 80 % of the classification of stocks in economic sectors. Similar results, though less sharp, are found for the other markets. We also find that the structure of correlations in the overnight returns is markedly different from that of intraday activity.
description: 12 pages, 17 figures
Scaling in large area field emitters and the emission dimension
Creators: name: Rudra, Rashbihari
name: Biswas, Debabrata
Publisher: name: arXiv
Year: 2021
Subjects: subject: Applied Physics (physics.app-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Accelerator Physics (physics.acc-ph)
subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: Electrostatic shielding is an important consideration for large area field emitters (LAFE) and results in a distribution of field enhancement factors even when the constituent emitters are identical. Ideally, the mean and variance together with the nature of the distribution should characterize a LAFE. In practice however, it is generally characterized by an effective field enhancement factor obtained from a linear fit to a Fowler-Nordheim plot of the $\text{I V}$ data. An alternate characterization is proposed here based on the observation that for a dense packing of emitters, shielding is large and LAFE emission occurs largely from the periphery, while well separated emitter tips show a more uniform or 2-dimensional emission. This observation naturally leads to the question of the existence of an emission-dimension, $D_e$ for characterizing LAFEs. We show here that the number of patches of size $L_P$ in the ON-state (above average emission) scales as $N(L_P) \sim L_P^{-D_e}$ in a given LAFE. The exponent $D_e$ is found to depend on the applied field (or voltage) and approaches $D_e = 2$ asymptotically.
description: 6 pages, 6 figures
A phenomenological approach to understanding the experience of parenting adolescent children
Creators: name: Wagner, Dale A.
Publisher: name: University of British Columbia
Year: 2009

description: A phenomenological methodology was utilized to investigate the lived parental experience of raising adolescent children. Five female and five male coresearchers participated in two taped interviews during which they were invited to describe their experiences with this phenomena. The transcripts were analyzed concurrently with the process of data collection with the objective of discovering the immanent meaning of the experiences to the parents who lived them. The study yielded seven dominant themes and nineteen subthemes which were deemed to represent the essential features of the experience of being a parent of an adolescent child. The seven dominant themes identified were: the experience of the loss of being needed or wanted; the experience of bewilderment; the search for confirmation of reality; the experience of the transition of power; the experience of disappointment and frustration; the experience of anxiety; and the experience of mutuality. Implications for counselling and further research were included in the discussion of the results.
การวิจัยพัฒนาเพื่อเพิ่มอัตราการทำงานของเครื่องสับเหง้ามันสำปะหลัง
Creators: name: เกียรติสุดา สุวรรณปา
Publisher: name: สถาบันวิจัยและพัฒนา มหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี
Year: 2019
Subjects: เครื่องสับเหง้ามันสำปะหลัง
อัตราการสับเหง้ามันสำปะหลัง
มันสำปะหลังพันธุ์ เกษตรศาสตร์ 50

description: วารสารวิจัยมหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี, 18, 2, 42-52
Exclusive J/psi and Upsilon hadroproduction and the QCD odderon
Creators: name: Bzdak, A.
name: Motyka, L.
name: Szymanowski, L.
name: Cudell, J. -R.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study pp and p\bar p collisions which lead to the exclusive production of J/psi or Upsilon from the pomeron-odderon and the pomeron-photon fusion. We calculate scattering amplitudes of these processes in the lowest order approximation and in the framework of k_T factorization. We present estimates of cross sections for the kinematic conditions of the Tevatron and of the LHC.
description: 21 pages, 5 figures
ตัวแบบการพยากรณ์ที่ส่งผลต่อยอดขายสินค้าที่ทำการส่งเสริมการขาย
Creators: name: ธันยพร เชี่ยวพานิชย์
Publisher: name: สถาบันวิจัยและพัฒนา มหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี
Year: 2019
Subjects: ตัวแบบการพยากรณ์
ยอดขายที่ทำการส่งเสริมการขาย
การวิเคราะห์ความถดถอยเชิงเส้นแบบพหุ

description: วารสารวิจัยมหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี, 18, 2, 32-41
Beer Mats make bad Frisbees
Creators: name: Ostmeyer, Johann
name: Schürmann, Christoph
name: Urbach, Carsten
Publisher: name: arXiv
Year: 2021
Subjects: subject: Popular Physics (physics.pop-ph)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Classical Physics (physics.class-ph)
subject: FOS: Physical sciences

description: In this article we show why flying and rotating beer mats, CDs, or other flat disks will eventually flip in the air and end up flying with backspin, thus, making them unusable as frisbees. The crucial effect responsible for the flipping is found to be the lift attacking not in the center of mass but slightly offset to the forward edge. This induces a torque leading to a precession towards backspin orientation. An effective theory is developed providing an approximate solution for the disk's trajectory with a minimal set of parameters. Our theoretical results are confronted with experimental results obtained using a beer mat shooting apparatus and a high speed camera. Very good agreement is found.
description: 4 videos in ancillary files
The relationship of empathy and self-esteem to the level of paternal involvement in child care
Creators: name: Schein, Howard Walter
Publisher: name: University of British Columbia
Year: 2009

description: There is a large body of work on the study of the relationship between parenting and child personality, but very little on the relationship between parenting and parental personality characteristics, and more specifically fathers (Baruch & Barnett, 1986b; Demo et al., 1987). The present research focuses on the relationship between paternal involvement in child care and the father's level of empathy and self esteem. A sample of 52 subjects was drawn largely from the academic community including 36 fathers and 16 non-fathers. This study is correlational in nature, but the comparison sample of non-fathers was used to determine any possible differences on the dependent variables among father's level of involvement, and between nonfathers and father's levels of paternal involvement. A questionnaire administered to the fathers requested demographic information, also contained the Empathic Concern (EC) and Perspective-taking (PT) scales of the Interpersonal Reactivity Index (Davis, 1980), the Rosenberg (1979) Self-esteem Scale (SE), and the Paternal Involvement in Child Care Index (PI) by (Radin & Harold-Goldsmith, 1985). The non-fathers received the same package, but were not requested to answer the PI scale. Subhypotheses for a relationship between recollection of paternal involvement and present paternal involvement, and the relationship between desire to become a parent and EC, PT, and SE, are also explored. The results indicated that there was not a significant positive relationship between paternal involvement and any of PT, EC, or SE. Analyses of the within father, and father versus nonfather groups indicates some support for higher self-esteem in the high paternal versus low paternal involvement groups. An inverse relationship is suggested between empathic concern and paternal involvement. Near significant results support these findings in the correlational analyses with paternal involvement. Findings for sub-hypotheses include support for a positive relationship between desire to father and perspective-taking for non-fathers. Results suggest enough support for further research in this area, including longitudinal research to determine potential direction of effect for any relationship between father's personality development specifically, or parents generally.
การเตรียมอนุภาคพอลิเมอร์ที่มีประสิทธิภาพสูงด้วยการสังเคราะห์พอลิเมอร์แบบอิมัลชันผ่านกลไกการเหนี่ยวนำให้ประกอบตัวเองด้วยการสังเคราะห์พอลิเมอร์
Creators: name: เนตรนภา กำลังมาก
Publisher: name: สถาบันวิจัยและพัฒนา มหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี
Year: 2020
Subjects: กลไกการเกิดอนุภาค
สารโยกย้ายสายโซ่มหภาคไอโอไดด์
การเหนี่ยวนำให้ประกอบตัวเองด้วยการสังเคราะห์พอลิเมอร์
อิมัลชัน ไอทีพี

description: วารสารวิจัยมหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี, 19, 1, 27-38
Truncated Star Formation in Compact Groups of Galaxies: A Stellar Population Study
Creators: name: de la Rosa, I. G.
name: de Carvalho, R. R.
name: Vazdekis, A.
name: Barbuy, B.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present the results of a study comparing the stellar populations in the elliptical galaxies of Hickson Compact Groups (HCGs) with those in low density environments. Three different population synthesis models and stellar population analyses are used to make the results more robust. The low-sigma galaxies in HCGs show an enhanced [Mg/Fe] ratio and a depleted metallicity [Z/H] with respect to their counterparts in the field. This behavior is interpreted as evidence for the action of a mechanism which truncated the star formation (SF). Hydrodynamical simulations of galaxy mergers (Di Matteo et al. 2005) support this interpretation by predicting the quenching of star formation soon after the merger event. Combining this scenario and the evidence presented here, the HCGs, generally considered to be ideal environments for galaxy-galaxy interactions, become ideal places for SF truncation.
description: 18 pages, 9 figures. Accepted for publication in Astronomical Journal
Το αδίκημα της παιδικής πορνογραφίας στο διαδίκτυο
Creators: name: Δαλιάνης, Σπυρίδων Ιωάννη
Publisher: name: Aristotle University of Thessaloniki
Year: 2017
Subjects: Παιδική πορνογραφία
Διαδίκτυο-Ανήλικος
Child pornography
Internet-Minor

description: Η παιδική πορνογραφία αποτελεί μία από τις σοβαρότερες και ειδεχθέστερες μορφές εγκληματικότητας της σημερινής εποχής, η οποία συνεχίζει να εξαπλώνεται σε παγκόσμιο επίπεδο. Η παρούσα διπλωματική εργασία επικεντρώνεται σε μία ειδικότερη και πιο διαδεδομένη σήμερα έκφανση του φαινομένου, σε αυτήν δηλαδή που τελείται με τη χρήση του διαδικτύου. Το πρώτο μέρος της εργασίας αφιερώνεται στην ανάλυση του φαινομένου της πορνογραφίας των ανηλίκων στο διαδίκτυο. Στο δεύτερο μέρος, επιχειρείται μία παρουσίαση του διεθνούς και ενωσιακού νομικού πλαισίου για την αντιμετώπιση του εγκλήματος. Το τρίτο μέρος αναλώνεται στην παράθεση της ελληνικής σχετικής νομοθεσίας, δίνοντας ιδιαίτερη έμφανση στην παρουσίαση και ερμηνεία της αξιόποινης συμπεριφοράς του άρθρου 348Α του ποινικού μας κώδικα, προβαίνοντας και σε μία κριτική προσέγγισή του. Στο τέταρτο και τελευταίο μέρος, παρουσιάζονται προτάσεις για την αποτελεσματικότερη αντιμετώπιση του φαινομένου και τα τελικά συμπεράσματα που συγκλίνουν στο ότι η αναγκαία προστασία των ανηλίκων και ο ποινικός κολασμός της παιδικής πορνογραφίας στο διαδίκτυο δεν θα πρέπει να φτάνουν σε τέτοιο σημείο υπερβολής, ώστε να διαταράσσεται ο φιλελεύθερος χαρακτήρας που διαχρονικά επιβάλλεται να διαπνέει το ποινικό μας δίκαιο
description: Child pornography is one of the most serious and hideous crimes of modern era, which continues to spread worldwide. This dissertation focuses on a more specific and more prevalent today facet of the phenomenon, the one that occurs with the use of the internet. The first part of this thesis is devoted to the analysis of the phenomenon of child pornography on the internet. In the second part, we attempt a presentation of international and EU legal framework for tackling the crime. The third part is spent in the tile of the relevant greek legislation, giving special emphasis in the presentation and interpretation of the criminal conduct of the article 348A of the greek penal code, making also a critical review of it. In the fourth and last part, are presented proposals for tackling the phenomenon more effectively and the final conclusions, that converge in that the necessary protection of minors and the criminal punishment of child pornography on the internet should not reach such a point of overkill, as to disturb the liberal character that over time should inspire our criminal law
ผลของการให้ความร้อนระดับสเตอริไรส์ต่อสมบัติทางกายภาพและเคมีของผลิตภัณฑ์ข้าวห่อใบบัวในบรรจุภัณฑ์รีทอร์ทเพาซ์
Creators: name: สุนัน ปานสาคร
Publisher: name: สถาบันวิจัยและพัฒนา มหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี
Year: 2020
Subjects: ข้าวห่อใบบัว
ใบบัว
การสเตอริไรส์
บรรจุภัณฑ์รีทอร์ทเพาซ์

description: วารสารวิจัยมหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี, 19, 1, 1-15
The Intrinsic Shapes of Low Surface Brightness Galaxies: a Discriminant of LSBG Formation Mechanisms
Creators: name: Kado-Fong, Erin
name: Petrescu, Mihai
name: Mohammad, Majid
name: Greco, Johnny
name: Greene, Jenny E.
name: Adams, Elizabeth A. K.
name: Huang, Song
name: Leisman, Lukas
name: Munshi, Ferah
name: Tanoglidis, Dimitrios
name: Van Nest, Jordan
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We use the low surface brightness galaxy (LSBG) samples created from the Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP, 781 galaxies), the Dark Energy Survey (DES, 20977 galaxies), and the Legacy Survey (selected via HI detection in the Arecibo Legacy Fast ALFA Survey, 188 galaxies) to infer the intrinsic shape distribution of the low surface brightness galaxy population. To take into account the effect of the surface brightness cuts employed when constructing LSBG samples, we simultaneously model both the projected ellipticity and the apparent surface brightness in our shape inference. We find that the LSBG samples are well-characterized by oblate spheroids, with no significant difference between red and blue LSBGs. This inferred shape distribution is in good agreement with similar inferences made for ultra-diffuse cluster galaxy samples, indicating that environment does not play a key role in determining the intrinsic shape of low surface brightness galaxies. We also find some evidence that LSBGs are more thickened than similarly massive high surface brightness dwarfs. We compare our results to intrinsic shape measures from contemporary cosmological simulations, and find that the observed LSBG intrinsic shapes place considerable constraints on the formation path of such galaxies. In particular, LSBG production via the migration of star formation to large radii produces intrinsic shapes in good agreement with our observational findings.
description: 19 pages, 10 figures, accepted to ApJ
Bootstrapping One-Loop QCD Amplitudes with General Helicities
Creators: name: Berger, Carola F.
name: Bern, Zvi
name: Dixon, Lance J.
name: Forde, Darren
name: Kosower, David A.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The recently developed on-shell bootstrap for computing one-loop amplitudes in non-supersymmetric theories such as QCD combines the unitarity method with loop-level on-shell recursion. For generic helicity configurations, the recursion relations may involve undetermined contributions from non-standard complex singularities or from large values of the shift parameter. Here we develop a strategy for sidestepping difficulties through use of pairs of recursion relations. To illustrate the strategy, we present sets of recursion relations needed for obtaining n-gluon amplitudes in QCD. We give a recursive solution for the one-loop n-gluon QCD amplitudes with three or four color-adjacent gluons of negative helicity and the remaining ones of positive helicity. We provide an explicit analytic formula for the QCD amplitude A_{6;1}(1^-,2^-,3^-,4^+,5^+,6^+), as well as numerical results for A_{7;1}(1^-,2^-,3^-,4^+,5^+,6^+,7^+), A_{8;1}(1^-,2^-,3^-,4^+,5^+,6^+,7^+,8^+), and A_{8;1}(1^-,2^-,3^-,4^-,5^+,6^+,7^+,8^+). We expect the on-shell bootstrap approach to have widespread applications to phenomenological studies at colliders.
description: 77 pages, 17 figures; v2, corrected minor typos in text and small equations
การพัฒนาขั้วไฟฟ้าแอโนดทังสเตนออกไซด์ร่วมบิสมัทวานาเดตสำหรับกำจัดสีย้อมด้วยเทคนิคโฟโตอิเล็กโตรคะตะไลติก
Creators: name: ฟารุจน์ สุภนันทิน
Publisher: name: สถาบันวิจัยและพัฒนา มหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี
Year: 2020
Subjects: โฟโตอิเล็กโตรคะตะไลติก
ทังสเตนออกไซด์
บิสมัทวานาเดต
การตรึงด้วยวิธีเคมีไฟฟ้า
การกำจัดสีย้อม

description: วารสารวิจัยมหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี, 19, 1, 16-26
Anisotropic $k$-essence
Creators: name: Orjuela-Quintana, J. Bayron
name: Valenzuela-Toledo, César A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In this paper, we study the late time cosmology of a non-canonical scalar field ($k$-essence) coupled to a vector field in a Bianchi-I background. Specifically, we study three cases: canonical scalar field (quintessence) with exponential potential as a warm up, the dilatonic ghost condensate, and the Dirac Born Infeld field with exponentials throat and potential. By using a dynamical system approach, we show that anisotropic dark energy fixed points can be attractors for a suitable set of parameters of each model. We also numerically integrate the associated autonomous systems for particular initial conditions chosen in the deep radiation epoch. We find that the three models can give an account of an equation of state of dark energy close to $-1$ nowadays. However, a non-negligible spatial shear within the observational bounds nowadays is possible only for thequintessence and the Dirac Born Infeld field. We also find that the equation of state of dark energy and the shear oscillate around nowadays, whenever the coupling of the k-essence field to the vector field is strong enough. The reason of these oscillations is explained in the appendix.
description: V2: Typos corrected and comments added, 18 pages, 8 figures. arXiv admin note: text overlap with arXiv:2012.09946
Quasi-exactly solvable models based on special functions
Creators: name: Dolya, S. N.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Mathematical Physics (math-ph)
subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We suggest a systematic method of extension of quasi-exactly solvable (QES) systems. We construct finite-dimensional subspaces on the basis of special functions (hypergeometric, Airy, Bessel ones) invariant with respect to the action of differential operators of the second order with polynomial coefficients. As a example of physical applications, we show that the known two-photon Rabi Hamiltonian becomes quasi-exactly solvable at certain values of parameters when it can be expressed in terms of corresponding QES operators related to the hypergeometric function.
description: 15 pages. Typos corrected
Matching matrix elements and shower evolution for top-quark production in hadronic collisions
Creators: name: Mangano, Michelangelo L.
name: Moretti, Mauro
name: Piccinini, Fulvio
name: Treccani, Michele
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study the matching of multijet matrix elements and shower evolution in the case of top production in hadronic collisions at the Tevatron and at the LHC. We present the results of the matching algorithm implemented in the ALPGEN Monte Carlo generator, and compare them with results obtained at the parton level, and with the predictions of the MC@NLO approach. We highlight the consistency of the matching algorithm when applied to these final states, and the excellent agreement obtained with MC@NLO for most inclusive quantities. We nevertheless identify also a remarkable difference in the rapidity spectrum of the leading jet accompanying the top quark pair, and comment on the likely origin of this discrepancy.
description: 22 pages, 13 figures, 5 tables. JHEP style
การเตรียมพอลิเมอร์ไมโครแคปซูลกักเก็บสารหอมด้วยเทคนิคพิกเกอริงอิมัลชัน
Creators: name: กัลปังหา รัตนไทรแก้ว
Publisher: name: สถาบันวิจัยและพัฒนา มหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี
Year: 2020
Subjects: ไมโครแคปซูล
การสังเคราะห์แบบแขวนลอย
พิกเกอริงอิมัลชัน
สารหอม
อนุภาคนาโนซิงค์ออกไซด์

description: วารสารวิจัย มหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี, 19, 1, 51-63
Μελέτη της Ιονόσφαιρας στον Ελλαδικό χώρο με χρήση της τεχνικής ΡΡΡ και του λογισμικού Bernese v5.2
Creators: name: Σπανακάκη, Κυριακή Στυλιανού
Publisher: name: Aristotle University of Thessaloniki
Year: 2017
Subjects: Ιονόσφαιρα
PPP (Precise Point Positioning)
TEC (Total Electron Content)
Ionosphere

description: Το GPS από την κατασκευή του αναπτύχθηκε κατά κύριο λόγο με σκοπό τον προσδιορισμό θέσης. Ωστόσο βρίσκει εφαρμογή σε πολλές διαφορετικές πτυχές της επιστήμης. Μία από αυτές είναι και η μελέτη της ιονόσφαιρας. Με αφορμή το γεγονός του σεισμού της 24ης Μαΐου 2014 στη θαλάσσια περιοχή της Σαμοθράκης μελετήθηκε η συγκέντρωση των ηλεκτρονίων (ΤΕC) της ιονόσφαιρας για την εβδομάδα 20-26 Μαΐου 2014, δηλαδή τρεις ημέρες πριν και δύο ημέρες μετά το συμβάν, καθώς και η αντίστοιχη ημέρα με αυτή του σεισμού την επόμενη χρονιά. Χρησιμοποιήθηκαν δεδομένα από εικοσιένα μόνιμους σταθμούς GNSS που βρίσκονται στην ευρύτερη περιοχή του επίκεντρου του σεισμού. Για τον προσδιορισμό του TEC της ιονόσφαιρας και τη δημιουργία των χαρτών ιονόσφαιρας χρησιμοποιήθηκε η μέθοδος μηδενικών διαφορών ΡΡΡ. Η επίλυση έγινε με το λογισμικό Bernese GNSS Version 5.2. Οι τελικοί χάρτες έγιναν με τη βοήθεια αλγορίθμου σε γλώσσα python και το πρόγραμμα GMT. Αποτέλεσμα της παρούσας εργασίας ήταν η κατασκευή συνολικά ενενήντα έξι χαρτών-στιγμιότυπων της ιονόσφαιρας ανά δύο ώρες, δώδεκα για κάθε ημέρα που μελετήθηκε, με εύρος από 48° έως 36° για τα πλάτη και 18° έως 36° για τα μήκη.
description: GPS by definition is mainly a positioning method. Although it is now days widely used in many different aspects of science. One of them is the study of the ionosphere. On the occasion of the May 24, 2014 strong earthquake in Samothrace the total electron content (TEC) of the ionosphere was evaluated for the week 20-26 of May, that is three days before and two days after the incident, as well as for the same day that the earthquake occurred next year. Data from twenty permanent GNSS stations located in the broader region of the epicenter of the earthquake were used. For the determination of TEC and the creation of ionospheric maps PPP method was used. The resolution was obtained with Bernese GNSS software Version 5.2. The final maps were made with an algorithm written in python and GMT software. The outcome of this essay was the construction of ninety six in total maps-snapshots of the ionosphere for every two hours, twelve for each day, ranging from 48° to 36° for latitudes and from 18° to 36° for longitudes.
The mass function of high redshift seed black holes
Creators: name: Lodato, Giuseppe
name: Natarajan, Priyamvada
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: In this paper we derive the mass function of seed black holes that result from the central mass concentrated via disc accretion in collapsed haloes at redshift $z\approx 15$. Using standard arguments including stability, we show that these pre-galactic discs can assemble a significant mass concentration in the inner regions, providing fuel for the formation and initial growth of super-massive black holes. Assuming that these mass concentrations do result in central seed black holes, we determine the mass distribution of these seeds as a function of key halo properties. The seed mass distribution determined here turns out to be asymmetric and skewed to higher masses. Starting with these initial seeds, building up to $10^9$ solar masses by $z = 6$ to power the bright quasars is not a problem in the standard LCDM cosmogony. These seed black holes in gas rich environments are likely to grow into the supermassive black holes at later times via mergers and accretion. Gas accretion onto these seeds at high redshift will produce miniquasars that likely play an important role in the reionization of the Universe. Some of these seed black holes on the other hand could be wandering in galaxy haloes as a consequence of frequent mergers, powering the off-nuclear ultra-luminous X-ray sources detected in nearby galaxies.
description: 5 pages, 4 color figures, MNRAS accepted. BH seeds mass functions based on the proposed model available upon request
Crossover of interface growth dynamics during corrosion and passivation
Creators: name: Reis, Fabio D. A. Aarao
name: Stafiej, Janusz
Publisher: name: arXiv
Year: 2006
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We study a model of corrosion and passivation of a metalic surface in contact with a solution using scaling arguments and simulation. The passive layer is porous so that the metal surface is in contact with the solution. The volume excess of the products may suppress the access of the solution to the metal surface, but it is then restored by a diffusion mechanism. A metalic site in contact with the solution or with the porous layer can be passivated with rate p and volume excess diffuses with rate D. At small times, the corrosion front linearly grows in time, but the growth velocity shows a t^{-1/2} decrease after a crossover time of order t_c ~ D/p^2, where the average front height is of order h_c ~ D/p. A universal scaling relation between h/h_c and t/t_c is proposed and confirmed by simulation for 0.00005 <= p <= 0.5 in square lattices. The roughness of the corrosion front shows a crossover from Kardar-Parisi-Zhang scaling to Laplacian growth (diffusion-limited erosion - DLE) at t_c. The amplitudes of roughness scaling are obtained by the same kind of arguments as previously applied to other competitive growth models. The simulation results confirm their validity. Since the proposed model captures the essential ingredients of different corrosion processes, we also expect these universal features to appear in real systems.
description: 17 pages, including 7 figures; submitted article
title: การบริหารทรัพยากรในยุคเศรษฐกิจหมุนเวียนเพื่อเสริมสร้างความยั่งยืน ในองค์กรปกครองส่วนท้องถิ่น: กรณีศึกษาจังหวัดปทุมธานี
Creators: name: รัฐบุรุษ คุ้มทรัพย์
Publisher: name: สหวิทยาการและความยั่งยืนปริทรรศน์ไทย
publisherIdentifierScheme: ROR
Year: 2025
Subjects: การบริหารทรัพยากร
ความยั่งยืน
เศรษฐกิจหมุนเวียน
องค์กรภาครัฐ

description: สหวิทยาการและความยั่งยืนปริทรรศน์ไทย, 14, 1, บทความที่ 18
Spherically symmetric exact vacuum solutions in Einstein-aether theory
Creators: name: Oost, Jacob
name: Mukohyama, Shinji
name: Wang, Anzhong
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study spherically symmetric spacetimes in Einstein-aether theory in three different coordinate systems, the isotropic, Painlevè-Gullstrand, and Schwarzschild coordinates, in which the aether is always comoving, and present both time-dependent and time-independent exact vacuum solutions. In particular, in the isotropic coordinates we find a class of exact static solutions characterized by a single parameter $c_{14}$ in closed forms, which satisfies all the current observational constraints of the theory, and reduces to the Schwarzschild vacuum black hole solution in the decoupling limit ($c_{14} = 0$). However, as long as $c_{14} \not= 0$, a marginally trapped throat with a finite non-zero radius always exists, and in one side of it the spacetime is asymptotically flat, while in the other side the spacetime becomes singular within a finite proper distance from the throat, although the geometric area is infinitely large at the singularity. Moreover, the singularity is a strong and spacetime curvature singularity, at which both of the Ricci and Kretschmann scalars become infinitely large.
description: revtex4-1, one figure and no tables. Some typos are corrected. Universe 7 (2021) 272
การใช้อินนูลินทดแทนน้ำตาลทรายในไอศกรีมนมเสริมอกไก่
Creators: name: จิราภัทร โอทอง
Publisher: name: สถาบันวิจัยและพัฒนา มหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี
Year: 2020
Subjects: ไอศกรีมนม
อกไก่
อินนูลิน

description: วารสารวิจัย มหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี, 19, 1, 39-50
Η Arte Povera: η διεθνής παρουσία του ρεύματος και η ελληνική εκδοχή του.
Creators: name: Αθανασιάδου, Μαρία Μιχαήλ
Publisher: name: Aristotle University of Thessaloniki
Year: 2017
Subjects: Άρτε Πόβερα
Γιάννης Κουνέλλης
Φτωχή Τέχνη
Arte Povera
Jannis Kounellis
Germano Celant

description: Η παρούσα μεταπτυχιακή εργασία προσεγγίζει το καλλιτεχνικό κίνημα της Arte Povera, που αναπτύχθηκε κατά τη διάρκεια της δεκαετίας του 1970 στην Ιταλία. Οι καλλιτέχνες του κινήματος είχαν σκοπό να αντιταχθούν σε ένα σύστημα που είχε μετατρέψει το καλλιτεχνικό έργο σε καταναλωτικό αντικείμενο. Επιδίωξαν να συνδέσουν την τέχνη με τη ζωή σε μια εποχή που επικρατούσε το αστικό στοιχείο και η βιομηχανική ανάπτυξη. Τα έργα των καλλιτεχνών της Arte Povera χαρακτηρίζονται από μια προγλωσσική μορφή, όπου επικρατούν τα ακατέργαστα υλικά και οι φόρμες που παραπέμπουν σε πρωτόγονες εποχές. Οι αναταραχές σε πολιτικό και κοινωνικό επίπεδο την εποχή εκείνη ευνόησαν και ανέδειξαν τη δράση τους. Ο κριτικός τέχνης Germano Celant ήταν εμπνευστής και δημιουργός αυτής της καλλιτεχνικής ομάδας. Οι Michelangelo Pistoletto, Mario Merz, Pino Pascali, Gilberto Zorio, Giulio Paolini, Giuseppe Penone και ο Γιάννης Κουνέλλης ήταν από τους καλλιτέχνες που αποτέλεσαν τον πυρήνα της Arte Povera
description: This Master’s thesis examines the artistic movement of Arte Povera, which was developed during the decade of the 1970s in Italy. The artists of this movement were strongly opposed to a system that had turned the object of art into a consumer object. In an era when the urban element and industrial development prevailed, they sought to connect art to life.The works of the Arte Povera artists are characterized by a prelinguistic form, where both the crude material and form refer to a primitive era. The climate of socio-political turmoil at that time, fostered and highlighted the work of the Arte Povera movement, whose founder was the art critic, Germano Celant. The artists Michelangelo Pistoletto, Mario Merz, Pino Pascali, Gilberto Zorio, Giulio Paolini, Giuseppe Penone and Jannis Kounellis comprised the core of Arte Povera.
การพัฒนาแบบจำลองทางคณิตศาสตร์ทำนายอุณหภูมิดินเพื่อเพาะกล้าไม้เบญจมาศ
Creators: name: จักรวาล บุญหวาน
Publisher: name: สถาบันวิจัยและพัฒนา มหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี
Year: 2020
Subjects: แบบจำลองทางคณิตศาสตร์
ระบบทำน้ำร้อนรังสีอาทิตย์
แผงรับรังสีอาทิตย์
อุณหภูมิดิน
เบญจมาศ

description: วารสารวิจัย มหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี, 19, 1, 74-85
ผลของเพคตินจากเปลือกแตงโมต่อคุณภาพของแยมกระเจี๊ยบแดง (Hibiscus sabdariffa L.)
Creators: name: อินทิรา ลิจันทร์พร
Publisher: name: สถาบันวิจัยและพัฒนา มหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี
Year: 2020
Subjects: เปลือกแตงโม
เพคติน
แยม

description: วารสารวิจัย มหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี, 19, 1, 64-73
Simulation of Shielding Parameters of Some High Entropy Alloys Containing Energies for Gamma Ray and Fast Neutron
Creators: name: Kittisak Sriwongsa
Publisher: name: สถาบันวิจัยและพัฒนา มหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี
Year: 2020
Subjects: alloy
mass attenuation coefficient
fast neutron

description: วารสารวิจัย มหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี, 19, 1, 97-105
On local linearization of control systems
Creators: name: Baratchart, Laurent
name: Pomet, Jean-Baptiste
Publisher: name: arXiv
Year: 2006
Subjects: subject: Optimization and Control (math.OC)
subject: FOS: Mathematics

description: We consider the problem of topological linearization of smooth (C infinity or real analytic) control systems, i.e. of their local equivalence to a linear controllable system via point-wise transformations on the state and the control (static feedback transformations) that are topological but not necessarily differentiable. We prove that local topological linearization implies local smooth linearization, at generic points. At arbitrary points, it implies local conjugation to a linear system via a homeomorphism that induces a smooth diffeomorphism on the state variables, and, except at "strongly" singular points, this homeomorphism can be chosen to be a smooth mapping (the inverse map needs not be smooth). Deciding whether the same is true at "strongly" singular points is tantamount to solve an intriguing open question in differential topology.
การพัฒนาอุปกรณ์อย่างง่ายที่อาศัยการแพร่ของแก๊สกับกระดาษที่ตรึงด้วยรีเอเจนต์ธรรมชาติและการวิเคราะห์ค่าสีจากภาพถ่ายดิจิทัลสำหรับวิเคราะห์แอมโมเนีย
Creators: name: นภาพร วรรณาพรม
Publisher: name: สถาบันวิจัยและพัฒนา มหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี
Year: 2020
Subjects: แก๊สแอมโมเนีย
อุปกรณ์ตรวจวัดแก๊สอย่างง่าย
สารสกัดจากธรรมชาติ
การวิเคราะห์ค่าสีจากภาพถ่ายดิจิทัล

description: วารสารวิจัย มหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี, 19, 1, 86-96
ระบบแนะนำส่วนบุคคลโดยใช้การจัดกลุ่มแบบลำดับชั้นร่วมกับวิธีการคัดกรองผู้ใช้และการคัดกรองสิ่งของร่วม
Creators: name: รัฐวรรณ พันธุนิล
Publisher: name: สถาบันวิจัยและพัฒนา มหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี
Year: 2020
Subjects: ระบบแนะนำ
วิธีการจัดกลุ่มแบบลำดับชั้น
วิธีแบบคัดกรองผู้ใช้ร่วม
วิธีแบบคัดกรองสิ่งของร่วม

description: วารสารวิจัย มหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี, 19, 1, 106-112
Present Acceleration of Universe, Holographic Dark Energy and Brans-Dicke Theory
Creators: name: Nayak, Bibekananda
name: Singh, Lambodar Prasad
Publisher: name: arXiv
Year: 2008
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: The present day accelerated expansion of the universe is naturally addressed within the Brans-Dicke theory just by using holographic dark energy model with inverse of Hubble scale as IR cutoff. It is also concluded that if the universe continues to expand, then one day it might be completely filled with dark energy.
description: 10 pages
The experience of heroic figures in young women of dirrerent identity statuses
Creators: name: Maske, Constance C
Publisher: name: University of British Columbia
Year: 2009

description: In this research study, the experience of having a heroic figure and associations with identity status are explored. Seven young women in Grade 12 were interviewed using a semi-structured, open-ended interview regarding their experience of having a heroic figure. This was followed by each participant being interviewed using the Clinical Identity Interview as developed by Marcia (1966) and adapted by Josselson (1987). Each heroic figure interview was analyzed using hermeneutic analysis, involving the isolation of meaning units (Giorgi, 1975) with the discovery of inherent themes. Five super ordinate themes and five subordinate themes which revolved around the roles played by the heroic figures in the lives of the participants were reported and discussed. The identity interviews were analyzed by an experienced independent researcher. Participants were assigned primary and secondary identity statuses and associations between identity status of participants and the functions of the heroic figure as experienced by participants were made. The results of this study provide support for the research which shows that women form their identity in connection with others, and often within the context of relationships. They also suggest that there is some association between the role the heroic figure plays in the life of the participant and the identity status of the participant. Heroic figures in this study helped young women work through crisis and explore alternatives and options, while also providing a safe place and a sense of belonging and connection to those young women who were only beginning their exploration.
การศึกษาและทดสอบเครื่องตัดใบบัวหลวง
Creators: name: จตุรงค์ ลังกาพินธุ์
Publisher: name: สถาบันวิจัยและพัฒนา มหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี
Year: 2020
Subjects: บัวหลวง
ใบบัวหลวง
เครื่องตัดใบบัวหลวง
การออกแบบ

description: วารสารวิจัย มหาวิทยาลัยเทคโนโลยีราชมงคลธัญบุรี, 19, 1, 113-123
Circularly polarized states and propagating bound states in the continuum in a periodic array of cylinders
Creators: name: Abdrabou, Amgad
name: Lu, Ya Yan
Publisher: name: arXiv
Year: 2021
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: Bound states in the continuum (BICs) in a periodic structure sandwiched between two homogeneous media have interesting properties and useful applications in photonics. The topological nature of BICs was previously revealed based on a topological charge related to the far-field polarization vector of the surrounding resonant states. Recently, it was established that when a symmetry-protected BIC (with a nonzero topological charge) is destroyed by a generic symmetry-breaking perturbation, a pair of circularly polarized resonant states (CPSs) emerge and the net topological charge is conserved. A periodic structure can also support propagating BICs with a nonzero wavevector. These BICs are not protected by symmetry in the sense of symmetry mismatch, but they need symmetry for their robust existence. Based on a highly accurate computational method for a periodic array of slightly noncircular cylinders, we show that a propagating BIC is typically destroyed by a structural perturbation that breaks only the in-plane inversion symmetry, and when this happens, a pair of CPSs of opposite handedness emerge so that the net topological charge is conserved. We also study the generation and annihilation of CPSs when a structural parameter is varied. It is shown that two CPSs with opposite topological charge and same handedness, connected to two BICs or in a continuous branch from one BIC, may collapse and become a CPS with a zero charge. Our study clarifies the important connection between symmetry and topological charge conservation.
GRBs as Cosmological Probes - Cosmic Chemical Evolution
Creators: name: Savaglio, S.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Long-duration gamma-ray bursts (GRBs) are associated with the death of metal-poor massive stars. Even though they are highly transient events very hard to localize, they are so bright that they can be detected in the most difficult environments. GRB observations are unveiling a surprising view of the chemical state of the distant universe (redshifts z > 2). Contrary to what is expected for a high-z metal-poor star, the neutral interstellar medium (ISM) around GRBs is not metal poor (metallicities vary from ~1/10 solar at z = 6.3 to about solar at z = 2) and is enriched with dust (90-99% of iron is in solid form). If these metallicities are combined with those measured in the warm ISM of GRB host galaxies at z < 1, a redshift evolution is observed. Such an evolution predicts that the stellar masses of the hosts are in the range M* = 10^(8.6-9.8) Msun. This prediction makes use of the mass-metallicity relation (and its redshift evolution) observed in normal star-forming galaxies. Independent measurements coming from the optical-NIR photometry of GRB hosts indicate the same range of stellar masses, with a typical value similar to that of the Large Magellanic Cloud. This newly detected population of intermediate-mass galaxies is very hard to find at high redshift using conventional astronomy. However, it offers a compelling and relatively inexpensive opportunity to explore galaxy formation and cosmic chemical evolution beyond known borders, from the primordial universe to the present.
description: Review article to be published in New Journal of Physics (http://www.njp.org), Focus Issue on Gamma Ray Bursts
Singlet ground state in the spin-1/2 dimer compound Sr3Cr2O8
Creators: name: Singh, Yogesh
name: Johnston, D. C.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Magnetic susceptibility and specific heat versus temperature measurements on polycrystalline samples of Sr3Cr2O8 and the isostructural, nonmagnetic compound Sr3V2O8 are reported. A Curie-Wiess fit to the high-temperature susceptibility data for Sr3Cr2O8 indicates that the Cr atoms are in the rare Cr^5+ (Spin S = 1/2) valence state as expected from the composition. The ground state was found to be a spin singlet with an excitation gap Delta/k_ B = 61.9(1) K to the magnetic triplet states, and a weak interdimer coupling of 6(2) K was inferred. The specific heat and susceptibility measurements on Sr3V2O8 reveal a phase transition at 110 K which is evidently a structural transition.
description: Revised version with 5 pages, 5 figures, 1 Table