Gushchin, Artem; Ooi, Bee Lean; Harris, Pernille;
2009-01-01
In our pursuit of mixed chalcogen-bridged cluster complexes, solids of the compositions Mo3SSe6Br4 and W3SSe6Br4 were prepared using high-temperature synthesis from the elements. Treatment of Mo3SSe6Br4 with Bu4NBr in a vibration mill yielded (Bu4N)(3)([Mo-3(mu(3)-S)(mu(2)-Se-2)(3)Br-6]Br} (I). I...
Triangular Fibrocartilage Complex MR Imaging
Seyed Hassan Mostafavi
2010-05-01
Full Text Available Interpretation of MR imaging of the wrist may be difficult because of the small size of this joint, its complex anatomy, and its sometimes poorly unders-tood pathologic lesions. A recent study revealed that MR imaging of the wrist influences clinicians' diagnoses and management plans in most patients. "nWhich structures make up the triangular fibrocarti-lage complex (TFCC are not universally agreed upon. In most descriptions, however, the TFCC is composed of the triangular fibrocartilage (TFC, the meniscus homolog, the ulnar collateral ligament, the dorsal and volar radioulnar ligaments and the sheath of the extensor carpi ulnaris tendon. The ulnolunate and ulnotriquetral ligaments may also be considered as part of the TFCC. These structures are a complex unit that function as a stabilizing element in the pivot movement of the radius and ulna and limit the lateral deviation of the carpus. The distal radioulnar joint is primarily stabilized by the TFCC. The TFC functions as a cushion between the ulnar head and carpal bones. Many of the structures that make up the complex are connected by fibrous bands. "nThis presentation summarizes the current diagnostic criteria that can be useful in interpreting abnormalities of the triangular fibrocartilage complex (TFCC of the wrist in this difficult topic in joint MR imaging
Uranium (VI)Bis(imido) chalcogenate complexes:synthesis and density functional theory analysis
Bis(imido) uranium(VI) trans- and cis-dichalcogenate complexes with the general formula U(NtBu)2(EAr)2(OPPh3)2 (EAr = O-2-tBuC6H4, SPh, SePh, TePh) and U(NtBu)2(EAr)2(R2bpy) (EAr = SPh, SePh, TePh) (R2bpy = 4,4'-disubstituted-2,2'-bipyridyl, R = Me, tBu) have been prepared. This family of complexes includes the first reported monodentate selenolate and tellurolate complexes of uranium(VI). Density functional theory calculations show that covalent interactions in the U-E bond increase in the trans-dichalcogenate series U(NtBu)2(EAr)2(OPPh3)2 as the size of the chalcogenate donor increases and that both 5f and 6d orbital participation is important in the M-E bonds of U-S, U-Se, and U-Te complexes.
Uranium (VI)Bis(imido) chalcogenate complexes:synthesis and density functional theory analysis
Spencer, Liam P [Los Alamos National Laboratory; Batista, Enrique R [Los Alamos National Laboratory; Boncella, James M [Los Alamos National Laboratory; Yang, Ping [Los Alamos National Laboratory; Scott, Brian L [Los Alamos National Laboratory
2009-01-01
Bis(imido) uranium(VI) trans- and cis-dichalcogenate complexes with the general formula U(NtBu)2(EAr)2(OPPh3)2 (EAr = O-2-tBuC6H4, SPh, SePh, TePh) and U(NtBu)2(EAr)2(R2bpy) (EAr = SPh, SePh, TePh) (R2bpy = 4,4'-disubstituted-2,2'-bipyridyl, R = Me, tBu) have been prepared. This family of complexes includes the first reported monodentate selenolate and tellurolate complexes of uranium(VI). Density functional theory calculations show that covalent interactions in the U-E bond increase in the trans-dichalcogenate series U(NtBu)2(EAr)2(OPPh3)2 as the size of the chalcogenate donor increases and that both 5f and 6d orbital participation is important in the M-E bonds of U-S, U-Se, and U-Te complexes.
Histological assessment of the triangular fibrocartilage complex.
Semisch, M; Hagert, E; Garcia-Elias, M; Lluch, A; Rein, S
2016-06-01
The morphological structure of the seven components of triangular fibrocartilage complexes of 11 cadaver wrists of elderly people was assessed microscopically, after staining with Hematoxylin-Eosin and Elastica van Gieson. The articular disc consisted of tight interlaced fibrocartilage without blood vessels except in its ulnar part. Volar and dorsal radioulnar ligaments showed densely parallel collagen bundles. The subsheath of the extensor carpi ulnaris muscle, the ulnotriquetral and ulnolunate ligament showed mainly mixed tight and loose parallel tissue. The ulnolunate ligament contained tighter parallel collagen bundles and clearly less elastic fibres than the ulnotriquetral ligament. The ulnocarpal meniscoid had an irregular morphological composition and loose connective tissue predominated. The structure of the articular disc indicates a buffering function. The tight structure of radioulnar and ulnolunate ligaments reflects a central stabilizing role, whereas the ulnotriquetral ligament and ulnocarpal meniscoid have less stabilizing functions. PMID:26685153
Chalcogenated Schiff bases: Complexation with palladium(II) and Suzuki coupling reactions
Pradhumn Singh; G K Rao; Mohd Salman Karim; Ajai K Singh
2012-11-01
Chalcogenated Schiff bases of 5-chloroisatin (L1-L3), 2-(methythio)benzaldehyde (L4), 2-acetylpyridine (L5) and benzaldehyde (L6-L7) have been synthesized. Both the carbonyl groups of 5- chloroisatin appear to be reactive (noticed for the first time) for making >C=N bond, of course one at a time only. The 1H, 13C{1H}, 77Se{1H} and 125Te{1H} NMR spectroscopy have been used to establish the coexistence of two products, which were found in the ratio 53:47 (E = S), 55:45 (E = Se) and 81:19 (E = Te). The larger amount is of the one in which C=O group away from NH is derivatized. The two products are not separable. Palladium complexes (1-4) of Schiff bases of other three aldehydes were synthesized. The ligands as well as complexes were characterized by multinuclear NMR spectroscopy. The crystal structures of [Pd(L4/L5)Cl][ClO4] (1/2) have been solved. The Pd-Se bond lengths are 2.4172(17) and 2.3675(4) Å, respectively for 1 and 2. The Pd-complexes (3-4) of L6-L7 were explored for Suzuki-Miyaura coupling and found promising as 0.006 mol % of 3 is sufficient to obtain good conversion with TON up to 1.58 × 104.
Majumdar, Subhojit; Stauber, Julia M; Palluccio, Taryn D; Cai, Xiaochen; Velian, Alexandra; Rybak-Akimova, Elena V; Temprado, Manuel; Captain, Burjor; Cummins, Christopher C; Hoff, Carl D
2014-10-20
The enthalpy of oxygen atom transfer (OAT) to V[(Me3SiNCH2CH2)3N], 1, forming OV[(Me3SiNCH2CH2)3N], 1-O, and the enthalpies of sulfur atom transfer (SAT) to 1 and V(N[t-Bu]Ar)3, 2 (Ar = 3,5-C6H3Me2), forming the corresponding sulfides SV[(Me3SiNCH2CH2)3N], 1-S, and SV(N[t-Bu]Ar)3, 2-S, have been measured by solution calorimetry in toluene solution using dbabhNO (dbabhNO = 7-nitroso-2,3:5,6-dibenzo-7-azabicyclo[2.2.1]hepta-2,5-diene) and Ph3SbS as chalcogen atom transfer reagents. The V-O BDE in 1-O is 6.3 ± 3.2 kcal·mol(-1) lower than the previously reported value for 2-O and the V-S BDE in 1-S is 3.3 ± 3.1 kcal·mol(-1) lower than that in 2-S. These differences are attributed primarily to a weakening of the V-Naxial bond present in complexes of 1 upon oxidation. The rate of reaction of 1 with dbabhNO has been studied by low temperature stopped-flow kinetics. Rate constants for OAT are over 20 times greater than those reported for 2. Adamantyl isonitrile (AdNC) binds rapidly and quantitatively to both 1 and 2 forming high spin adducts of V(III). The enthalpies of ligand addition to 1 and 2 in toluene solution are -19.9 ± 0.6 and -17.1 ± 0.7 kcal·mol(-1), respectively. The more exothermic ligand addition to 1 as compared to 2 is opposite to what was observed for OAT and SAT. This is attributed to less weakening of the V-Naxial bond in ligand binding as opposed to chalcogen atom transfer and is in keeping with structural data and computations. The structures of 1, 1-O, 1-S, 1-CNAd, and 2-CNAd have been determined by X-ray crystallography and are reported. PMID:25280113
Diagnosis of triangular fibrocartilage complex injury using arthrography and MRI
Kato, Kiyonobu; Soejima, Osamu; Naito, Masatoshi [Fukuoka Univ. (Japan). School of Medicine
2001-09-01
Twenty patients (twenty-one wrists) with chronic ulnar wrist pain who had undergone radiocarpal arthrography and MRI before arthroscopic examination were evaluated to determine the usefulness of these preoperative diagnostic procedures (arthrogrphy and MRI) for the detection of triangular fibrocartilage complex (TFCC) injury. Based on the arthroscopic findings, the sensitivity and specificity of arthrography were 63% and 100% respectively for detecting TFCC lesions, while they were 68% and 50% respectively for MRI. Although no significant superiority was observed between arthrography and MRI in this study, further improrumchts in the preoperative diagnostic procedures are still needed in order to more accurately detect TFCC injuries. (author)
The complexes formed by H2CO, CH3CHO, and (CH3)2CO with 1, 2, and 3 molecules of CO2 are studied by ab initio calculations. Three different types of heterodimers are observed, most containing a tetrel bond to the C atom of CO2, and some supplemented by a CH⋅⋅O H-bond. One type of heterodimer is stabilized by an anti-parallel arrangement of the C=O bonds of the two molecules. The binding energies are enhanced by methyl substitution on the carbonyl, and vary between 2.4 and 3.5 kcal/mol. Natural bond orbital analysis identifies a prime source of interaction as charge transfer into the π*(CO) antibonding orbital. Heterotrimers and tetramers carry over many of the geometrical and bonding features of the binary complexes, but also introduce O⋅⋅O chalcogen bonds. These larger complexes exhibit only small amounts of cooperativity
Dorsal Tear of Triangular Fibrocartilage Complex: Clinical Features and Treatment.
Abe, Yukio; Moriya, Atsushi; Tominaga, Yasuhiro; Yoshida, Koji
2016-03-01
Background Several different triangular fibrocartilage complex (TFCC) tear patterns have been classified through the use of wrist arthroscopy. A tear of the dorsal aspect of the TFCC has been previously reported, but it is not included in Palmer original classification. Our purpose was to describe this type of tear pattern along with the clinical presentation. Methods An isolated dorsal TFCC tear was encountered in seven wrists of six patients (three men and three women; average age was 31 years). All patients were evaluated by physical exam, X-ray, plain axial computed tomography with pronation, neutral and supination position, magnetic resonance imaging (MRI) with coronal, sagittal, and axial section and arthroscopy. Results The clinical findings varied and included the following: tenderness at the dorsoulnar aspect of the wrist was positive in all wrists, fovea sign was positive in five wrists, and tenderness at the dorsal aspect of the distal radioulnar joint was present in one wrist. Pain with forearm rotation was positive in all wrists. The ulnar head ballottement test induced pain in all wrists, whereas dorsal instability of the ulnar head was present in one wrist with this test. The ulnocarpal stress test was positive in five wrists. Axial and sagittal images on MRI revealed the dorsal tear in five wrists. All wrists were treated with an arthroscopic capsular repair. The final functional outcome at an average follow-up of 16.1 months was four excellent and one good wrist according to the modified Mayo wrist score. Conclusions The aim of this article is to describe our experiences with tears involving the dorsal aspect of the TFCC, which may be misdiagnosed if the surgeon is not cognizant of this injury. Type of study/level of evidence Diagnostic/level IV. PMID:26855835
On the Reduction of a Complex Matrix to Triangular or Diagonal by Consimilarity
Tongsong Jiang; Musheng Wei
2006-01-01
Two n × n complex matrices A and B are said to be consimilar if S-1 AS = B for some nonsingular n × n complex matrix S. This paper, by means of real representation of a complex matrix, studies problems of reducing a given n × n complex matrix A to triangular or diagonal form by consimilarity, not only gives necessary and sufficient conditions for contriangularization and condiagonalization of a complex matrix, but also derives an algebraic technique of reducing a matrix to triangular or diagonal form by consimilarity.
The electronic stucture of chalcogen impurities in silicon which give rise to deep levels in the forbidden band gap of that semiconductor is studied. The molecular cluster model within the formalism of the multiple scattering method in the Xα local density approximation was used . The surface orbitals were treated by using the Watson sphere model. Studies were carried out for the isolated substitutional sulfur and selenium impurities (Si:S and Si:Se). A pioneer investigation was performed for the nearest-neighbor impurity pairs of sulfur and selenium (Si:S2 and Si:Se2). All the systems were also analysed in the positive charge states (Si:S+, Si:Se+ and Si:Se2+) and for the isolated impurities the calculations were carried out to the spin polarized limit. The obtained results were used to interpret recent photoconductivity, photocapitance, EPR and DLTS data on these centers. It was observed that the adopted model is able to provide a satisfactory description of the electronic structure of the chalcogen impurity centers in silicon. (autor)
The allylic chalcogen effect in olefin metathesis
Yuya A. Lin
2010-12-01
Full Text Available Olefin metathesis has emerged as a powerful tool in organic synthesis. The activating effect of an allylic hydroxy group in metathesis has been known for more than 10 years, and many organic chemists have taken advantage of this positive influence for efficient synthesis of natural products. Recently, the discovery of the rate enhancement by allyl sulfides in aqueous cross-metathesis has allowed the first examples of such a reaction on proteins. This led to a new benchmark in substrate complexity for cross-metathesis and expanded the potential of olefin metathesis for other applications in chemical biology. The enhanced reactivity of allyl sulfide, along with earlier reports of a similar effect by allylic hydroxy groups, suggests that allyl chalcogens generally play an important role in modulating the rate of olefin metathesis. In this review, we discuss the effect of allylic chalcogens in olefin metathesis and highlight its most recent applications in synthetic chemistry and protein modifications.
Ugur Anil Bingol, MD; Can Cinar, MD; Neslihan Tasdelen, MD
2015-01-01
Summary: Ganglions are the most frequently seen soft-tissue tumors in the hand. Nerve compression due to ganglion cysts at the wrist is rare. We report 2 ganglion cysts arising from triangular fibrocartilage complex, one of which caused ulnar nerve compression proximal to the Guyonʼs canal, leading to ulnar neuropathy. Ganglion cysts seem unimportant, and many surgeons refrain from performing a general hand examination.
Ugur Anil Bingol, MD
2015-03-01
Full Text Available Summary: Ganglions are the most frequently seen soft-tissue tumors in the hand. Nerve compression due to ganglion cysts at the wrist is rare. We report 2 ganglion cysts arising from triangular fibrocartilage complex, one of which caused ulnar nerve compression proximal to the Guyonʼs canal, leading to ulnar neuropathy. Ganglion cysts seem unimportant, and many surgeons refrain from performing a general hand examination.
Bingol, Ugur Anil; Cinar, Can; Tasdelen, Neslihan
2015-03-01
Ganglions are the most frequently seen soft-tissue tumors in the hand. Nerve compression due to ganglion cysts at the wrist is rare. We report 2 ganglion cysts arising from triangular fibrocartilage complex, one of which caused ulnar nerve compression proximal to the Guyon's canal, leading to ulnar neuropathy. Ganglion cysts seem unimportant, and many surgeons refrain from performing a general hand examination. PMID:25878929
Initial clinical experience of MRI microscopy coil to triangular fibrocartilage complex
This paper presents the efficacy of high-resolution MRI using a microscopy coil at 1.5 T for diagnosing triangular fibrocartilage complex (TFCC) injury, compared with arthroscopy and arthrography. All subjects were imaged in the prone position with the arm over the head. The wrist was kept in the pronation position and a microscopy coil was placed on the center of ulnar head. All MR images were obtained at 1.5 T. Two-dimensional gradient-echo (GRE), short tau inversion recovery (STIR) and fast spin echo (FSE) images of the wrist were acquired using a microscopy coil (47 mm in diameter). Eight patients with injured TFCC were studied with both arthrography and MRI, and three patients were studied with both arthroscopy and MRI. The structures of TFCC were classified into 6 regions (radius attachment, disc proper, triangular ligament, lunate-triquetral attachment, volar side radio-ulnar ligament, and dorsal side radio-ulnar ligament), and were evaluated by one orthopedics surgeon and two radiologists. It was possible to distinguish each structure of the TFCC using high-resolution MRI with a microscopy coil. The injuries were pointed out at radius attachment in 3 patients, disc proper in 4, triangular ligament in 4, dorsal side radio-ulnar ligament in 3, volar side radioulnar ligament in 7, and lunate-triquetral attachment in 7 on MRI. Using arthroscopy, injuries at lunate-triquetral attachment in 1, dorsal side radio-ulnar ligament, and triangular ligament in 3 were not observed possibly because of dorsal approach. Another TFCC injuries on MRI in 3 patients were consistent with those with arthroscopy. High-resolution MRI with a microscopy coil allowed to describe most of TFCC injuries, and to evaluate triangular ligament, lunate-triquetral attachment and dorsal side radio-ulnar ligament, which could not be observed by arthroscopy and arthrography. (author)
Arthroscopic Trans-osseous Suture of Peripheral Triangular Fibrocartilage Complex Tear.
Jegal, Midum; Heo, Kang; Kim, Jong Pil
2016-10-01
The importance of foveal repair of the triangular fibrocartilage complex (TFCC) on stability of the distal radioulnar joint (DRUJ) has been emphasized with increasing knowledge of the anatomy and biomechanics of the TFCC and DRUJ. Although both open and arthroscopic techniques have been described for improving DRUJ stability, there has been a marked evolution of arthroscopic TFCC repair technique with successful clinical outcome. Recently, an arthroscopic trans-osseous technique has been described to repair foveal tears of the TFCC. The advantage of the technique is that it allows for anatomical repair of both the superficial and deep layers. This article describes the details of this novel technique. PMID:27595945
Anion Transport with Chalcogen Bonds.
Benz, Sebastian; Macchione, Mariano; Verolet, Quentin; Mareda, Jiri; Sakai, Naomi; Matile, Stefan
2016-07-27
In this report, we introduce synthetic anion transporters that operate with chalcogen bonds. Electron-deficient dithieno[3,2-b;2',3'-d]thiophenes (DTTs) are identified as ideal to bind anions in the focal point of the σ holes on the cofacial endocyclic sulfur atoms. Anion binding in solution and anion transport across lipid bilayers are found to increase with the depth of the σ holes of the DTT anionophores. These results introduce DTTs and related architectures as a privileged motif to engineer chalcogen bonds into functional systems, complementary in scope to classics such as 2,2'-bipyrroles or 2,2'-bipyridines that operate with hydrogen bonds and lone pairs, respectively. PMID:27433964
Objective: To compare direct magnetic resonance (MR) arthrography with arthroscopy of the wrist for evaluation of injury in the triangular fibrocartilage complex (TFCC). Methods: Fourteen cases with suspicion of injury of triangular fibrocartilage complex were performed with conventional MR and direct MR arthrography, 10 cases were done by arthroscopy. In the direct MR arthrography, needle placement was obtained using clinical landmark under sterile technique and fluoroscopy, intra-articular injection was performed at the radius-scaphoid space with 5-7 ml 0.3% mixture of Gadolinium (0.1 mmol/ L) and saline(0.3 ml Gd-DTPA + 100 ml saline). The findings of MRI and MR arthrography were analyzed with results of arthroscopy. Results: (1) Among 14 cases with injury of TFCC, there were ulnar tear in 5 cases, radius tear in 4 cases, complete tear in 5 cases (included 2 cases with long term rheumatoid). (2) High signal intensity and isointensity signal of injury of TFCC were revealed on STIR or T2WI and T1WI respectively, normal hypointensity signal of the TFCC was partially or completely absent. Contrast media at the ulnar insertion (5 cases with ulnar tear) or radius attachment of the TFCC (4 cases with radius tear) were seen in the MR arthrography with different extent, 5 cases with complete tear showed contrast media at the both ulnar insertion and radius attachment of the TFCC. The findings of MR arthrography were well corresponded with results of arthroscopy on the lesion site, including ulnar tear in 3 cases, radius tear in 4 cases and complete tear in 3 cases. (3) Among 14 cases with TFCC, 8 cases had dislocation of radius-ulnar joint, 6 cases had bone contusion of radius or ulnar, synovial reaction was also clearly depicted on conventional MRI and direct MR arthrography in all cases. Conclusion: Compared with results of arthroscopy, direct MR arthrography can adequately reveal the injury of the triangular fibrocartilage complex, synoviat reaction and edema changes
Fontès, D
2006-11-01
Lesions of the triangular fibrocartilage complex of the wrist (TFCC) have perfectly been dismembered by Andrew Palmer and have largely benefited from progress of arthroscopy of the wrist. One distinguishes thus traumatic lesions (class 1) individualized according to their localization, central (1-A), ulnar (1-B), radial (1-D) or distal (1-C). Central lesions are classically associated to a positive ulnar variance. The clinical symptomatology evokes a meniscal like syndrome of the wrist. In case of failure of the medical treatment, it will be necessary to propose a surgical procedure guided by histopathology of the triangular complex. Thus, ulnar peripheral richly vascularized lesions (1-B) could therefore potentially heal and will have to benefit by an attempt of surgical reattachment (arthroscopic technique of Whipple, Poehling or other techniques) or by an osteosynthesis in case of fracture on the basis on the ulnar styloid process. Central fibrocartilage lesions (1-A) or radial avulsions (1-D) are less vascularized and have therefore little probability to heal; they will benefit then ideally from the endoscopic debridement of unstable flaps of the central portion of TFCC. No immobilization is required and rehabilitation is immediately undertaken. Less frequent class 1-C lesions justify in our practice a simple arthroscopic regularization, alone complete ruptures could have necessitate a direct suture. Class 2 degenerative lesions are graduated (A to E) according to evolution of the chondromalacia of the ulnar head and carpal bone, perforation of the central disc and lunotriquetral ligament degeneration. They are usually associated with a constitutional or an acquired ulnar plus variance syndrome, for example after a distal radius fracture malunion. The clinical symptomatology needs to differentiate them from the simple frequent physiological perforations after the age of 50 years. Arthroscopy will allow to regularize unstable non-vascularized lesions and to
Woo, Sung Jong; Jegal, Midum; Park, Min Jong
2016-01-01
Background: Disruption of the triangular fibrocartilage complex (TFCC) foveal insertion can lead to distal radioulnar joint (DRUJ) instability accompanied by ulnar-sided pain, weakness, snapping, and limited forearm rotation. We investigated the clinical outcomes of patients with TFCC foveal tears treated with arthroscopic-assisted repair. Materials and Methods: Twelve patients underwent foveal repair of avulsed TFCC with the assistance of arthroscopy between 2011 and 2013. These patients were followed up for an average of 19 months (range 14–25 months). The avulsed TFCC were reattached to the fovea using a transosseous pull-out suture or a knotless suture anchor. At the final followup, the range of motion, grip strength and DRUJ stability were measured as objective outcomes. Subjective outcomes were assessed using the Visual Analog Scale (VAS) for pain, patient rated wrist evaluation (PRWE), Disabilities of the Arm, Shoulder and Hand questionnaire (DASH score) and return to work. Results: Based on the DRUJ stress test, 5 patients had normal stability and 7 patients showed mild laxity as compared with the contralateral side. Postoperatively, the mean range of pronation supination increased from 141° to 166°, and the mean VAS score for pain decreased from 5.3 to 1.7 significantly. The PRWE and DASH questionnaires also showed significant functional improvement. All patients were able to return to their jobs. However, two patients complained of persistent pain. Conclusions: Arthroscopically assisted repair of TFCC foveal injury can provide significant pain relief, functional improvement and restoration of DRUJ stability. PMID:27293286
To evaluate pathology of the triangular fibrocartilage complex (TFCC) using high-resolution morphologic magnetic resonance (MR) imaging, and compare with quantitative MR and biomechanical properties. Five cadaveric wrists (22-70 years) were imaged at 3 T using morphologic (proton density weighted spin echo, PD FS, and 3D spoiled gradient echo, 3D SPGR) and quantitative MR sequences to determine T2 and T1rho properties. In eight geographic regions, morphology of TFC disc and laminae were evaluated for pathology and quantitative MR values. Samples were disarticulated and biomechanical indentation testing was performed on the distal surface of the TFC disc. On morphologic PD SE images, TFC disc pathology included degeneration and tears, while that of the laminae included degeneration, degeneration with superimposed tear, mucinous transformation, and globular calcification. Punctate calcifications were highly visible on 3D SPGR images and found only in pathologic regions. Disc pathology occurred more frequently in proximal regions of the disc than distal regions. Quantitative MR values were lowest in normal samples, and generally higher in pathologic regions. Biomechanical testing demonstrated an inverse relationship, with indentation modulus being high in normal regions with low MR values. The laminae studied were mostly pathologic, and additional normal samples are needed to discern quantitative changes. These results show technical feasibility of morphologic MR, quantitative MR, and biomechanical techniques to characterize pathology of the TFCC. Quantitative MRI may be a suitable surrogate marker of soft tissue mechanical properties, and a useful adjunct to conventional morphologic MR techniques. (orig.)
Nakamura, Toshiyasu [Fujita Health Univ., Nagoya (Japan). Second Hospital; Yabe, Yutaka; Horiuchi, Yukio; Kikuchi, Yoshito; Makita, Satoo
1996-08-01
Advances in magnetic resonance imaging (MRI) now allow for the visualization of small structures, such as the triangular fibrocartilage complex (TFCC) of the wrist. Recent investigators suggested that MRI is useful in delineation of the TFCC itself and its abnormality, and supported that diagnostic value of MRI for the TFCC tears is almost equal to those of arthrography and arthroscopy. In contrast, there were several reports that representation of the TFCC in MRI was less worth than in arthrography. Further, it was reported that MRI was not useful because abnormal findings existed at normal volunteers` wrists. Recent development of the pulse sequence is remarkable, such as gradient echo, fast spin echo and fat suppression method. However, as the previous MR studies of the TFCC mainly using conventional spin echo pulse sequence, there were a few comparison of each pulse sequence and we do not know how each pulse sequence delineates the TFCC. Therefore, we studied MRI of the TFCC using several pulse sequence in normal volunteers, and compared MR slices of the TFCC with corresponding histological sections to evaluate shape detectability of MRI. (J.P.N.)
Bae, Won C.; Chang, Eric Y.; Chung, Christine B. [VA San Diego Healthcare System, Radiology Service, San Diego, CA (United States); University of California-San Diego, Department of Radiology, San Diego, CA (United States); Ruangchaijatuporn, Thumanoon [Mahidol University, Department of Diagnostic and Therapeutic Radiology, Faculty of Medicine Ramathibodi Hospital, Rachathewi, Bangkok (Thailand); Biswas, Reni; Du, Jiang; Statum, Sheronda [University of California-San Diego, Department of Radiology, San Diego, CA (United States)
2016-04-15
To evaluate pathology of the triangular fibrocartilage complex (TFCC) using high-resolution morphologic magnetic resonance (MR) imaging, and compare with quantitative MR and biomechanical properties. Five cadaveric wrists (22-70 years) were imaged at 3 T using morphologic (proton density weighted spin echo, PD FS, and 3D spoiled gradient echo, 3D SPGR) and quantitative MR sequences to determine T2 and T1rho properties. In eight geographic regions, morphology of TFC disc and laminae were evaluated for pathology and quantitative MR values. Samples were disarticulated and biomechanical indentation testing was performed on the distal surface of the TFC disc. On morphologic PD SE images, TFC disc pathology included degeneration and tears, while that of the laminae included degeneration, degeneration with superimposed tear, mucinous transformation, and globular calcification. Punctate calcifications were highly visible on 3D SPGR images and found only in pathologic regions. Disc pathology occurred more frequently in proximal regions of the disc than distal regions. Quantitative MR values were lowest in normal samples, and generally higher in pathologic regions. Biomechanical testing demonstrated an inverse relationship, with indentation modulus being high in normal regions with low MR values. The laminae studied were mostly pathologic, and additional normal samples are needed to discern quantitative changes. These results show technical feasibility of morphologic MR, quantitative MR, and biomechanical techniques to characterize pathology of the TFCC. Quantitative MRI may be a suitable surrogate marker of soft tissue mechanical properties, and a useful adjunct to conventional morphologic MR techniques. (orig.)
Covalency in the f-element-chalcogen bond
Ingram, Kieran I.M. [Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ (United Kingdom); Kaltsoyannis, Nikolas [Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ (United Kingdom)], E-mail: n.kaltsoyannis@ucl.ac.uk; Gaunt, Andrew J.; Neu, Mary P. [Inorganic, Isotope and Actinide Chemistry (C-IIAC), Chemistry Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)
2007-10-11
The geometric and electronic structures of the title complexes have been studied using gradient corrected density functional theory. Excellent agreement is observed between computed r(M-E) and experimental values in analogous {sup i}Pr complexes. Natural charge analysis indicates that the M-E bond becomes less ionic in the order O>S>S> Te, and that this decrease is largest for U and smallest for La. Natural and Mulliken overlap populations suggest increasing M-E covalency as group 16 is descended, and also in the order La
Covalency in the f-element-chalcogen bond
The geometric and electronic structures of the title complexes have been studied using gradient corrected density functional theory. Excellent agreement is observed between computed r(M-E) and experimental values in analogous iPr complexes. Natural charge analysis indicates that the M-E bond becomes less ionic in the order O>S>S> Te, and that this decrease is largest for U and smallest for La. Natural and Mulliken overlap populations suggest increasing M-E covalency as group 16 is descended, and also in the order La< Pu< U for a given chalcogen. Increased covalency down group 16 arises from increased metal d (and s) participation in the bonding, while that from La to Pu and U stems from larger 5f orbital involvement compared with 4f
Supramolecular macrocycles reversibly assembled by Te…O chalcogen bonding
Ho, Peter C.; Szydlowski, Patrick; Sinclair, Jocelyn; Elder, Philip J. W.; Kübel, Joachim; Gendy, Chris; Lee, Lucia Myongwon; Jenkins, Hilary; Britten, James F.; Morim, Derek R.; Vargas-Baca, Ignacio
2016-01-01
Organic molecules with heavy main-group elements frequently form supramolecular links to electron-rich centres. One particular case of such interactions is halogen bonding. Most studies of this phenomenon have been concerned with either dimers or infinitely extended structures (polymers and lattices) but well-defined cyclic structures remain elusive. Here we present oligomeric aggregates of heterocycles that are linked by chalcogen-centered interactions and behave as genuine macrocyclic species. The molecules of 3-methyl-5-phenyl-1,2-tellurazole 2-oxide assemble a variety of supramolecular aggregates that includes cyclic tetramers and hexamers, as well as a helical polymer. In all these aggregates, the building blocks are connected by Te…O–N bridges. Nuclear magnetic resonance spectroscopic experiments demonstrate that the two types of annular aggregates are persistent in solution. These self-assembled structures form coordination complexes with transition-metal ions, act as fullerene receptors and host small molecules in a crystal. PMID:27090355
Hess, Florian; Farshad, Mazda; Sutter, Reto; Nagy, Ladislav; Schweizer, Andreas
2012-11-01
We performed this study to investigate whether discrepancy of bilateral dorsovolar shift of the distal radioulnar joint (DRUJ) is decisive for the diagnosis of DRUJ instability. Although several cadaver studies have quantified the amount of physiological dorsovolar shift, so far, there is no reliable method of quantification of DRUJ mobility in daily practice. The aim was to describe a novel sonographic method of quantifying DRUJ instability and evaluate its reliability and validity. In this study, 40 healthy volunteers and 17 patients with complete rupture of the triangular fibrocartilage complex (TFCC) underwent sonographic quantification of the grade of instability of their DRUJ bilaterally. Dorsovolar ulnar head translation relative to the distal radius was quantified by means of ultrasonography performed in a transversal plane through the ulnar head and Lister tubercle. Measurements were done while actively pressing the volar surface of the hand onto a brick 30 degrees pronated, and after lifting the hand. A quotient Q of the radioulnar distance (distance between the dorsal radius surface and the ulnar head) between the unloaded and loaded wrist was calculated for differentiation of a normal and unstable DRUJ. The Q ratio of the 17 patients with unilateral TFCC lesion was significantly different between the pathologic side and the contralateral wrist (1.19 vs. 0.54, p 0.8 was found to be a reasonable cut-off for pathologic laxity of the DRUJ with a sensitivity of 88% and a specificity of 81%. A quotient Q > 0.8 determines instability of the DRUJ reliably. This was a level II diagnostic study. PMID:24179720
Ten healthy volunteers (4 males and 6 females, 21-27 years old mean 25.3) were included in this study. All subjects were imaged in a prone position with the arm over the head. A microscopy coil (47 mm in diameter) was placed on the center of ulna head. Two-dimensional gradient-echo (GRE) images of the wrist were acquired with TR/TE/FA=374-385/11-12/40, 1.5 mm slice thickness, and 50 mm field of view. We used two fixation tools developed for radial-deviated position'' and ''ulnar-deviated position''. Images of the subjects were obtained in three positions; radial-deviated, ulnar-deviated and neutral position. The deformation of the articular disc (length and thickness of the radial and ulnar attachments, and the mid-portion between them) of triangular fibrocartilage complex (TFCC) was measured using a personal computer (software Get Curvature Radius) and data analysis was conducted by the One-way Repeated-Measures ANOVA test. P<0.05 was set as the significant difference. All subjects were not injured at TFCC, S-L ligament and L-T ligament. The mean of radial deviation angle was 19.0±3.2 deg, ulnar deviation is 37.1±6.4 deg. The disc length on radial deviation was significantly longer than that on neutral and ulnar-deviated position. The disc at ulnar side on radial-deviated position was significantly thicker than that on neutral and ulnar-deviated position. No significant difference was observed in the size of the center of disk and radial attachment among three positions. On radial deviation of the wrist, the disc of TFCC increased in length and increased in thickness at ulnar side of TFCC, probably because the peripheral part of disc was pulled toward ulnar and peripheral directions. (author)
Chandra, Sankhabrata; Rana, Bhaskar; Periyasamy, Ganga; Bhattacharya, Atanu
2016-06-01
Here we demonstrate, compare and contrast relaxation- and correlation-driven charge migration dynamics in halogen, chalcogen, pnicogen and tetrel bonded clusters, following their vertical ionization. For this work, we have selected different isolated A-X:NH3 clusters, where A represents F, Cl, CN and NH2 substituents and X features Cl, SH, PH2 and SiH3 to exhibit specific noncovalent bonding interaction. The charge migration dynamics in these clusters is studied using the density functional theory (DFT) with the wB97XD functional and the 6-31+G(d,p) basis set. Approximately 400-600 attosecond time scale is predicted for charge migration in (1:1) AX:NH3 complexes. Effects of basis set and intermolecular distance on the ultrafast charge migration dynamics through the halogen, chalcogen, pnicogen, and tetrel bonded clusters are also discussed. This is the first report on pure relaxation- and correlation-driven charge migration dynamics in chalcogen, pnicogen and tetrel bonded clusters.
Simultaneous triangularization
Radjavi, Heydar
2000-01-01
A collection of matrices is said to be triangularizable if there is an invertible matrix S such that S1 AS is upper triangular for every A in the collection. This generalization of commutativity is the subject of many classical theorems due to Engel, Kolchin, Kaplansky, McCoy and others. The concept has been extended to collections of bounded linear operators on Banach spaces: such a collection is defined to be triangularizable if there is a maximal chain of subspaces of the Banach space, each of which is invariant under every member of the collection. Most of the classical results have been generalized to compact operators, and there are also recent theorems in the finite-dimensional case. This book is the first comprehensive treatment of triangularizability in both the finite and infinite-dimensional cases. It contains numerous very recent results and new proofs of many of the classical theorems. It provides a thorough background for research in both the linear-algebraic and operator-theoretic aspects of tr...
Chimie Douce Synthesis of Chalcogen-Doped Manganese Oxides
Chalcogen-doped manganese oxides have been prepared by Chimie Douce redox reaction between permanganate and chalcogen element fine powder under acidic condition (pH = 1). According to powder X-ray diffraction analyses, the S- and Se-doped manganese oxides are crystallized with layered birnessite and tunnel-type α-MnO2 structures, respectively. On the contrary, Te-doped compound was found to be X-ray amorphous. According to EDS analyses, these compounds contain chalcogen dopants with the ratio of chalcogen/manganese = 4-7%. We have investigated the chemical bonding character of these materials with X-ray absorption spectroscopic (XAS) analysis. Mn K-edge XAS results clearly demonstrated that the manganese ions are stabilized in octahedral symmetry with the mixed oxidation states of +3/+4. On the other hand, according to Se K- and Te L1-edge XAS results, selenium and tellurium elements have the high oxidation states of +6, which is surely due to the oxidation of neutral chalcogen element by the strong oxidant permanganate ion. Taking into account their crystal structures and Mn oxidation states, the obtained manganese oxides are expected to be applicable as electrode materials for lithium secondary batteries
Marcelo Sthel
2013-05-01
Full Text Available The concept of sustainable complex triangular cells may be applied to an individual of any human society. This concept was introduced in two recent articles. A case study was proposed to show the applicability of this new concept to Indian populations without contact with civilization and with a low environmental impact. Here we propose to apply this concept to a recent study, which claims that the concept of “common but differentiated responsibilities” refers to the emissions of individuals instead of nations. The income distribution of a country was used to estimate how its fossil fuel CO2 emissions are distributed among its citizens and, from that a global CO2 distribution was constructed. We propose the extension of the concept of complex triangular cells where its area would be equivalent to the CO2 emission per individual. In addition, a new three-dimensional geometric model for the regular hexagonal structure is offered in which the sharing of natural resources (human cooperation is employed to reduce CO2 emissions in two scenarios by 2030.
Guo, Xin; An, Xiulin; Li, Qingzhong
2015-04-01
Quantum-chemical calculations have been performed for the chalcogen- and halogen-bonded complexes of F2CSe with a series of nitrogen bases (N2, NCH, NH3, NHCH2, NCLi, and NMe3) and dihalogen molecules (BrCl, ClF, and BrF), respectively. Both types of interactions are mainly driven by the electrostatic and orbital interactions. The chalcogen bond becomes stronger in the order of NCH (sp) < NH3 (sp(3)) < NHCH2 (sp(2)), showing some inconsistence with the electronegativity of the hybridized N atom. The Li and methyl groups have an enhancing effect on the strength of chalcogen bond; however, the former is jointly achieved through the electrostatic and orbital interactions, whereas the orbital interaction has dominant contribution to the latter enhancement. The halogen bond with F2CX (X = O, S, Se) as the electron donor is stronger for the heavier chalcogen atom, exhibiting a reverse dependence on the chalcogen atom with that in hydrogen bonds. The halogen bond is further strengthened by the presence of chalcogen bond in the ternary complexes. In addition, CSD research confirms the abundance of Se···N interaction in crystal materials. PMID:25797149
Congenital Triangular Alopecia
Yin Li, Vincent Chum; Yesudian, Paul Devakar
2015-01-01
Congenital triangular alopecia (CTA) also known as temporal triangular alopecia is a benign noncicatricial pattern of hair loss. It typically affects the frontotemporal region and rarely involves the temporoparietal or occipital scalp. It is a nonprogressive disorder that presents as a triangular, oval or lancet-shaped patch of alopecia. CTA can manifest at birth or develop later in life. The exact etiology of this condition remains unknown. Rarely, it may be associated with other disorders s...
Computing Cylindrical Algebraic Decomposition via Triangular Decomposition
Chen, Changbo; Maza, Marc Moreno; Xia, Bican; Yang, Lu
2009-01-01
Cylindrical algebraic decomposition is one of the most important tools for computing with semi-algebraic sets, while triangular decomposition is among the most important approaches for manipulating constructible sets. In this paper, for an arbitrary finite set $F \\subset {\\R}[y_1, ..., y_n]$ we apply comprehensive triangular decomposition in order to obtain an $F$-invariant cylindrical decomposition of the $n$-dimensional complex space, from which we extract an $F$-invariant cylindrical algeb...
Lee, Ryan K.L.; Ng, Alex W.H.; Tong, Cina S.L.; Griffith, James F. [The Chinese University of Hong Kong, Department of Imaging and Interventional Radiology, Prince Of Wales Hospital, Shatin (China); Tse, W.L.; Wong, C.; Ho, P.C. [The Chinese University of Hong Kong, Department of Imaging and Interventional Radiology, Prince Of Wales Hospital, Shatin (China); The Chinese University of Hong Kong, Department of Orthopedics, Prince Of Wales Hospital, Shatin (China)
2013-09-15
This study compares the diagnostic performance of multidetector CT arthrography (CTA), conventional 3-T MR and MR arthrography (MRA) in detecting intrinsic ligament and triangular fibrocartilage complex (TFCC) tears of the wrist. Ten cadaveric wrists of five male subjects with an average age 49.6 years (range 26-59 years) were evaluated using CTA, conventional 3-T MR and MRA. We assessed the presence of scapholunate ligament (SLL), lunotriquetral ligament (LTL), and TFCC tears using a combination of conventional arthrography and arthroscopy as a gold standard. All images were evaluated in consensus by two musculoskeletal radiologists with sensitivity, specificity, and accuracy being calculated. Sensitivities/specificity/accuracy of CTA, conventional MRI, and MRA were 100 %/100 %/100 %, 66 %/86 %/80 %, 100 %/86 %/90 % for the detection of SLL tear, 100 %/80 %/90 %, 60 %/80 %/70 %, 100 %/80 %/90 % for the detection of LTL tear, and 100 %/100 %/100 %, 100 %/86 %/90 %, 100 %/100 %/100 % for the detection of TFCC tear. Overall CTA had the highest sensitivity, specificity, and accuracy among the three investigations while MRA performed better than conventional MR. CTA also had the highest sensitivity, specificity, and accuracy for identifying which component of the SLL and LTL was torn. Membranous tears of both SLL and LTL were better visualized than dorsal or volar tears on all three imaging modalities. Both CT and MR arthrography have a very high degree of accuracy for diagnosing tears of the SLL, LTL, and TFCC with both being more accurate than conventional MR imaging. (orig.)
Pairs of chalcogen impurities in silicon
The electronic structure of complex defects in silicon involving oxygen and sulfur (O-O, S-O and S-S), occupying different positions in the host crystal is studied. It is shown that the many-electron effects (via configuration interaction) are important to describe the correct ground state. The orbital base set is obtained through the LCAO-MO-INDO/S method. (author)
Purpose: To determine the value of applying finger trap distraction during direct MR arthrography of the wrist to assess intrinsic ligament and triangular fibrocartilage complex (TFCC) tears. Materials and methods: Twenty consecutive patients were prospectively investigated by three-compartment wrist MR arthrography. Imaging was performed with 3-T scanners using a three-dimensional isotropic (0.4 mm) T1-weighted gradient-recalled echo sequence, with and without finger trap distraction (4 kg). In a blind and independent fashion, two musculoskeletal radiologists measured the width of the scapholunate (SL), lunotriquetral (LT) and ulna-TFC (UTFC) joint spaces. They evaluated the amount of contrast medium within these spaces using a four-point scale, and assessed SL, LT and TFCC tears, as well as the disruption of Gilula's carpal arcs. Results: With finger trap distraction, both readers found a significant increase in width of the SL space (mean Δ = +0.1 mm, p ≤ 0.040), and noticed more contrast medium therein (p ≤ 0.035). In contrast, the differences in width of the LT (mean Δ = +0.1 mm, p ≥ 0.057) and UTFC (mean Δ = 0 mm, p ≥ 0.728) spaces, as well as the amount of contrast material within these spaces were not statistically significant (p = 0.607 and ≥0.157, respectively). Both readers detected more SL (Δ = +1, p = 0.157) and LT (Δ = +2, p = 0.223) tears, although statistical significance was not reached, and Gilula's carpal arcs were more frequently disrupted during finger trap distraction (Δ = +5, p = 0.025). Conclusion: The application of finger trap distraction during direct wrist MR arthrography may enhance both detection and characterisation of SL and LT ligament tears by widening the SL space and increasing the amount of contrast within the SL and LT joint spaces
Cerny, Milena; Marlois, Romain [Department of Diagnostic and Interventional Radiology, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Rue du Bugnon 46, 1011 Lausanne (Switzerland); Theumann, Nicolas [Institute of Radiology, Clinique Hirslanden Bois-Cerf, Avenue d’Ouchy 31, 1006 Lausanne (Switzerland); Bollmann, Christof; Wehrli, Laurent [Department of Plastic and Hand Surgery, Clinique Longeraie and Centre Hospitalier Universitaire Vaudois, University of Lausanne, Avenue de la Gare 9, 1003 Lausanne (Switzerland); Richarme, Delphine [Institute of Radiology, Clinique Hirslanden Bois-Cerf, Avenue d’Ouchy 31, 1006 Lausanne (Switzerland); Meuli, Reto [Department of Diagnostic and Interventional Radiology, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Rue du Bugnon 46, 1011 Lausanne (Switzerland); Becce, Fabio, E-mail: fabio.becce@chuv.ch [Department of Diagnostic and Interventional Radiology, Centre Hospitalier Universitaire Vaudois, University of Lausanne, Rue du Bugnon 46, 1011 Lausanne (Switzerland)
2013-10-01
Purpose: To determine the value of applying finger trap distraction during direct MR arthrography of the wrist to assess intrinsic ligament and triangular fibrocartilage complex (TFCC) tears. Materials and methods: Twenty consecutive patients were prospectively investigated by three-compartment wrist MR arthrography. Imaging was performed with 3-T scanners using a three-dimensional isotropic (0.4 mm) T1-weighted gradient-recalled echo sequence, with and without finger trap distraction (4 kg). In a blind and independent fashion, two musculoskeletal radiologists measured the width of the scapholunate (SL), lunotriquetral (LT) and ulna-TFC (UTFC) joint spaces. They evaluated the amount of contrast medium within these spaces using a four-point scale, and assessed SL, LT and TFCC tears, as well as the disruption of Gilula's carpal arcs. Results: With finger trap distraction, both readers found a significant increase in width of the SL space (mean Δ = +0.1 mm, p ≤ 0.040), and noticed more contrast medium therein (p ≤ 0.035). In contrast, the differences in width of the LT (mean Δ = +0.1 mm, p ≥ 0.057) and UTFC (mean Δ = 0 mm, p ≥ 0.728) spaces, as well as the amount of contrast material within these spaces were not statistically significant (p = 0.607 and ≥0.157, respectively). Both readers detected more SL (Δ = +1, p = 0.157) and LT (Δ = +2, p = 0.223) tears, although statistical significance was not reached, and Gilula's carpal arcs were more frequently disrupted during finger trap distraction (Δ = +5, p = 0.025). Conclusion: The application of finger trap distraction during direct wrist MR arthrography may enhance both detection and characterisation of SL and LT ligament tears by widening the SL space and increasing the amount of contrast within the SL and LT joint spaces.
The MRI diagnosis of triangular fibrocartilage complex injures in the wrist%腕三角纤维软骨复合体损伤的MRI诊断
万梦楠; 周胜法; 林锋; 陈久尊; 何家维; 郑显秋
2016-01-01
目的：探讨3．0T MRI在腕关节三角纤维软骨复合体（TFCC）损伤中的价值。方法回顾性分析26例TFCC损伤的MRI及X线平片、CT表现。结果26例X线检查13例阴性，5例茎突骨折，2例桡骨远端骨折，2例月骨坏死，6例尺骨径突阳性征。5例多层螺旋CT扫描，发现骨折或／和骨坏死2例。26例MRI检查中，21例诊断TFCC损伤，其中包括TFCC撕裂或穿孔8例，主要表现为在MRI脂肪抑制序列（ STIR）、2D MERGE及T2 WI上点状、条片状高信号，在T1 WI序列上呈等信号；9例腕部骨折（包括尺骨茎突5例，桡骨2例，腕骨2例）；3例三角骨或月骨坏死；8例尺桡骨或腕骨挫伤；10例腕关节腔积液。结论 TFCC形态细小而不规则，损伤时X线平片和CT检查价值有限，MRI多序列多方位薄层图像对显示其损伤及邻近骨质病变有重要价值。%Objective To investigate the value of 3.0 T MRI in triangular fibrocartilage complex (TFCC) injures in the wrist. Methods The MRI, X-ray and CT characteristics of 26 cases of TFCC injuries were analyzed retrospectively .Results Of the 26 cases with X-ray examination , 13 were negative cases , 5 ulnar styloid fracture , 2 distal radial fracture , 2 lunate necrosis and 6 positive ulnar styloid.5 cases underwent multi-slice CT scan, of which 2 cases had fracture or/and necrosis, others hadn’t ab-normal sign.Of the 26 patients underwent MRI examination , 21 cases were diagnosed as TFCC injuries including 8 cases with TF-CC tear or perforation which were mainly spotty and stripped hyperintense on MRI short time inverse recovery ( STIR ) , 2DMERGE and T2 WI and isointense on T 1 WI;9 were wrist fracture (5 ulnar styloid, 2 radius and 2 wrists);3 were triangular bone or lunate necrosis;8 were radius and ulna or wrist contusion and 10 wrist joints effusion.Bone contusion was long T 1 and long T2 , including bone fracture with bone trabecular or bone cortex breaking .Conclusion The
Pfirrmann, C.W.A. [Dept. of Radiology, Veterans Administration Medical Center, San Diego, CA (United States); Dept. of Radiology, Orthopedic University Hospital Balgrist, Zurich (Switzerland); Theumann, N.H. [Dept. of Radiology, Veterans Administration Medical Center, San Diego, CA (United States); Service de Radiologie, CHUV, Lausanne (Switzerland); Chung, C.B.; Trudell, D.J.; Resnick, D. [Dept. of Radiology, Veterans Administration Medical Center, San Diego, CA (United States); Botte, M.J. [Div. of Orthopedic Surgery, Scripps Clinic and Research Foundation, La Jolla, CA (United States)
2001-12-01
Objective: To evaluate the dynamic morphologic changes of the triangular fibrocartilage complex (TFCC) during pronation and supination of the forearm using high-resolution MR arthrography in cadavers and to evaluate the impact of these changes on the diagnostic assessment of the normal and abnormal TFCC. Design and specimens: High-resolution MR arthrography of 10 wrists of cadaveric specimens was obtained in maximum pronation, in the neutral position, and in maximum supination of the forearm. The structures of the TFCC were evaluated by two musculoskeletal radiologists and correlated with anatomic sections. The position of the forearm that allowed the best visualization of normal structures and lesions of the TFCC was determined. Results: The shape and extent of the articular disc as well as the radial portions of the radioulnar ligaments did not change with pronation and supination. The articular disc was horizontal in the neutral position and tilted more distally to align with the proximal carpal row in pronation and supination. The fibers of the ulnar part of the radioulnar ligaments (ulnar attachment of the articular disc) revealed the most significant changes: their orientation was coronal in the neutral position and sagittal in positions of pronation and supination. The ulnomeniscal homologue was largest in the neutral position and was reduced in size during pronation and supination. The extensor carpi ulnaris tendon was centered in its groove in the neutral position and pronation. In supination this tendon revealed subluxation from this groove. The dorsal capsule of the distal radioulnar joint was taut in pronation, and the palmar capsule was taut in supination. The preferred forearm position for analysis of most of the structures of the TFCC was the neutral position, followed by the pronated position. The neutral position was rated best for the detection of ulnar and radial detachments of the TFCC, followed by the pronated position, except for two central
Objective: To evaluate the dynamic morphologic changes of the triangular fibrocartilage complex (TFCC) during pronation and supination of the forearm using high-resolution MR arthrography in cadavers and to evaluate the impact of these changes on the diagnostic assessment of the normal and abnormal TFCC. Design and specimens: High-resolution MR arthrography of 10 wrists of cadaveric specimens was obtained in maximum pronation, in the neutral position, and in maximum supination of the forearm. The structures of the TFCC were evaluated by two musculoskeletal radiologists and correlated with anatomic sections. The position of the forearm that allowed the best visualization of normal structures and lesions of the TFCC was determined. Results: The shape and extent of the articular disc as well as the radial portions of the radioulnar ligaments did not change with pronation and supination. The articular disc was horizontal in the neutral position and tilted more distally to align with the proximal carpal row in pronation and supination. The fibers of the ulnar part of the radioulnar ligaments (ulnar attachment of the articular disc) revealed the most significant changes: their orientation was coronal in the neutral position and sagittal in positions of pronation and supination. The ulnomeniscal homologue was largest in the neutral position and was reduced in size during pronation and supination. The extensor carpi ulnaris tendon was centered in its groove in the neutral position and pronation. In supination this tendon revealed subluxation from this groove. The dorsal capsule of the distal radioulnar joint was taut in pronation, and the palmar capsule was taut in supination. The preferred forearm position for analysis of most of the structures of the TFCC was the neutral position, followed by the pronated position. The neutral position was rated best for the detection of ulnar and radial detachments of the TFCC, followed by the pronated position, except for two central
Kremer, Adrian; Fermi, Andrea; Biot, Nicolas; Wouters, Johan; Bonifazi, Davide
2016-04-11
The high-yielding synthesis of 2-substituted benzo-1,3-tellurazoles and benzo-1,3-selenazoles through a dehydrative cyclization reaction has been reported, giving access to a large variety of benzo-1,3-chalcogenazoles. Exceptionally, these aromatic heterocycles proved to be very stable and thus very handy to form controlled solid-state organizations in which wire-like polymeric structures are formed through secondary N⋅⋅⋅Y bonding interactions (SBIs) engaging the chalcogen (Y=Se or Te) and nitrogen atoms. In particular, it has been shown that the recognition properties of the chalcogen centre at the solid state could be programmed by selectively barring one of its σ-holes through a combination of electronic and steric effects exerted by the substituent at the 2-position. As predicted by the electrostatic potential surfaces calculated by quantum chemical modelling, the pyridyl groups revealed to be the stronger chalcogen bonding acceptors, and thus the best ligand candidate for programming the molecular organization at the solid state. In contrast, the thiophenyl group is an unsuitable substituent for establishing SBIs in this molecular system as it gives rise to chalcogen-chalcogen repulsion. The weaker chalcogen donor properties of the Se analogues trigger the formation of feeble N⋅⋅⋅Se contacts, which are manifested in similar solid-state polymers featuring longer nitrogen-chalcogen distances. PMID:26899235
三角纤维软骨复合体的MRI 技术研究%Magnetic resonance imaging of the triangular fibrocartilage complex
纪涛涛; 毛传万; 王雪; 刘倩; 张瑞方; 叶信健; 严志汉; 何家维
2015-01-01
Objective To investigate the value of MR 3D fs SPGR(three-dimensional fat-suppressed spoiled gradient echo se-quence)in displaying the general structure of normal triangular fibrocartilage complex(triangular fibrocartilage disc,palm dorsal dis-tal radioulnar ligament,ulnolunate ligament,ulnotriquetral ligament,ulnar collateral ligament,extensor carpi sheath and articular disc homologues).Methods 1 5 normal adults(30 carpals)were examined withconventional sequences including axial fast spin-echo T1-weighted images (FSE T1 WI)or T2-weighted images (T2 WI),coronal fat-suppressed fast spin-echo T2-weighted images (FSE fsT2 WI)and coronal 3D fs SPGR.As well,3D image reconstruction was performed.Two experienced radiologists read the images with an agreement and recorded the display rate of general structure of TFCC.Results Triangular fibrocartilage disc,articular disc homologuespalm,dorsal distal radioulnar ligament,and extensor carpi sheath were totally showed on coronal and cross sections.Ulnolunate liga-ment and ulnotriquetral ligament were totally seen on the coronal plane,and the display rates on cross-section were 93.3%(28/30), 96.7%(29/30)respectively.Ulnar collateral ligament was seen on cross-section and coronal plane 83.3%(25/30),86.7%(26/30)re-spectively.Conclusion Coronal 3D fs SPGR sequence can be used as a regular sequence for observing TFCC and the surrounding lig-aments .%目的：探讨3.0T MRI 三维脂肪抑制扰相梯度回波技术(3D fs SPGR)对正常三角纤维软骨复合体(TFCC)的大体结构(三角纤维软骨盘、桡尺远端掌背侧韧带、尺月韧带、尺三角韧带、尺侧副韧带、尺侧腕伸肌腱鞘及关节盘同系物)的显示情况。方法成人健康志愿者15例(30例腕关节)，分别用轴位快速自旋回波 T1加权像(FSE T1 WI)或 T2加权像(T2 WI)，冠状位快速自旋回波脂肪抑制 T2加权像(FSE fsT2 WI)，冠状位3D fs SPGR 对30例腕关节进行常规扫描，后将3D 序列图像重建，由2
Congenital temporal triangular alopecia.
Bargman, H
1984-01-01
Congenital temporal triangular alopecia is a form of nonscarring alopecia that, as its name suggests, is present at birth. Four cases are reported. One patient underwent hair transplantation, which was successful and might be useful in other patients. Cases occurring in a father and his son suggest for the first time a genetic link.
Series of Reciprocal Triangular Numbers
Bruckman, Paul; Dence, Joseph B.; Dence, Thomas P.; Young, Justin
2013-01-01
Reciprocal triangular numbers have appeared in series since the very first infinite series were summed. Here we attack a number of subseries of the reciprocal triangular numbers by methodically expressing them as integrals.
TREATMENT OF TRIANGULAR FIBROCARTILAGE COMPLEX TEAR UNDER WRIST ARTHROSCOPY%腕关节镜下治疗三角纤维软骨复合体损伤
米琨; 刘武; 刘鹏飞; 俸志斌; 李玉文; 惠桂生
2011-01-01
目的 探讨腕关节镜下治疗三角纤维软骨复合体(triangular fibrocartilage complex,TFCC)损伤的方法及疗效.方法 2006年1月-2008年12月,收治TFCC损伤16例.男11例,女5例;年龄25～51岁,平均32.5岁.扭伤12例,跌伤4例.左侧10例,右侧6例.病程3个月～6年2个月.主要临床症状为腕关节尺侧疼痛、无力,用力握拳和提重物时疼痛明显.尺腕应力试验阳性14例,阴性2例.术前腕关节掌屈(45.58±5.18)°,背伸(41.22±3.83)°,桡偏(17.82±2.48)°,尺偏(21.35±4.61)°,旋前(69.85±8.36)°,旋后(70.13±6.34)°.术中根据腕关节镜下观察情况,对损伤按照Palmer刨伤性TFCC分类标准进行分类并行相应治疗.其中10例Ⅰ A类损伤行清理术;3例Ⅰ B类损伤中2例行缝合修补,1例缝合失败改部分切除术;2例Ⅰ C类损伤对损伤的三角软骨盘及尺月韧带和尺三角韧带进行清创;1例Ⅰ D类损伤采取汽化修整成形术.结果 术后切口均Ⅰ期愈合,未发生关节感染及神经、血管损伤等并发症.患者均获随访,随访时间14～38个月,平均18.5个月.15例恢复正常生活、工作,无腕关节尺侧疼痛发生;1例无疼痛发生,但腕关节无力.末次随访时腕关节掌屈(50.16±6.21)°,背伸(45.37±4.65)°,桡偏(18.95±3.56)°,尺偏(26.28±5.09)°,旋前(78.87±7.69)°,旋后(76.46±8.31)°,与术前相应指标比较差异均有统计学意义(JP＜0.05).采用Green-O'Brien功能评定方法进行评定,获优9例,良6例,可1例,优良率93.75%.结论 腕关节镜下治疗TFCC损伤既能明确诊断,又能进行相应处理,且创伤小,功能恢复快,可有效避免腕尺侧疼痛的发生.%Objective To evaluate the treatment and effects of wrist arthroscopy in tear of triangular fibrocartilage complex (TFCC). Methods Between January 2006 and December 2008, 16 patients with tear of TFCC were treated. Of 16 patients, 11 were male and 5 were female with an average age of 32.5 years (range, 25-51 years). Injury
Synthesized Optimization of Triangular Mesh
HU Wenqiang; YANG Wenyu
2006-01-01
Triangular mesh is often used to describe geometric object as computed model in digital manufacture, thus the mesh model with both uniform triangular shape and excellent geometric shape is expected. But in fact, the optimization of triangular shape often is contrary with that of geometric shape. In this paper, one synthesized optimizing algorithm is presented through subdividing triangles to achieve the trade-off solution between the geometric and triangular shape optimization of mesh model. The result mesh with uniform triangular shape and excellent topology are obtained.
Congenital Triangular Alopecia.
Yin Li, Vincent Chum; Yesudian, Paul Devakar
2015-01-01
Congenital triangular alopecia (CTA) also known as temporal triangular alopecia is a benign noncicatricial pattern of hair loss. It typically affects the frontotemporal region and rarely involves the temporoparietal or occipital scalp. It is a nonprogressive disorder that presents as a triangular, oval or lancet-shaped patch of alopecia. CTA can manifest at birth or develop later in life. The exact etiology of this condition remains unknown. Rarely, it may be associated with other disorders such as Down's syndrome and phakomatosis pigmentovascularis. The diagnosis is based on its distinct clinical appearance. Histologically, hair follicles are miniaturized and replaced by sparse vellus hair follicles. Tricoscopy using a polarized light handheld dermatoscope can be a useful diagnostic tool. CTA is often asymptomatic and remains unchanged throughout the life. No treatment is required. Surgical intervention with follicular unit hair transplantation can provide a satisfactory cosmetic result. In this paper, we have identified 126 cases of CTA in the published literature cited on PubMed between 1905 and 2015. From the available evidence, 79% of patients with CTA presented with unilateral hair loss, 18.5% with bilateral involvement and rarely, with occipital alopecia (2.5%). There was no gender predilection. These figures are entirely consistent with previously published data. Physicians should remember to consider CTA as a potential diagnosis in any patient presenting with a nonscarring alopecia in order to avoid unnecessary investigations and treatments. PMID:26180448
Lutz, Patricia B; Bayse, Craig A
2016-04-01
Reducible sulfur and selenium (r-S/Se) compounds, defined as sulfur and selenium compounds not in the lowest -2 oxidation state (e.g., -1 to +6), release Zn(2+) from zinc-sulfur proteins such as zinc fingers (ZFs) and metallothionein. A series of density functional theory calculations was performed on donor-acceptor complexes between r-S/Se compounds and models of the Cys2His2, Cys3His and Cys4 ZF sites. These S⋯S/Se chalcogen bonding interactions consist of the donation of electron density from a S lone pair on the ZF model to a S/Se-X antibonding molecular orbital of the r-S/Se compound. The strength of the interaction was shown to be dependent upon the Lewis basicity of the ZF model (Cys4>Cys3His>Cys2His2) and the Lewis acidity of the r-S/Se compound as measured by the energy of the S/Se-X antibonding orbital. Interactions with the softer r-Se compounds were stronger than the r-S compounds, consistent with the greater reactivity of the former with ZF proteins. PMID:26877152
In a hydrodynamic model, with fluctuating initial conditions, the correlation between triangular flow and initial spatial triangularity is studied. The triangular flow, even in ideal fluid, is not strongly correlated with the initial triangularity. The correlation is largely reduced in viscous fluid. Elliptic flow on the other hand appears to be strongly correlated with initial eccentricity. Weak correlation between triangular flow and initial triangularity indicates that a part of triangular flow is unrelated to initial triangularity. Triangularity acquired during the fluid evolution also contributes to the triangular flow.
A series of chalcogen esters 1a, 6a and 6b have been synthesized in a straightforward manner. Polarized-light optical microscopy (POM) and differential scanning calorimetry (DSC) showed that these chalcogen esters displayed a wide nematic range of mesophase. In addition, UV-Vis in solution (ca.10-5 mol L-1) was applied in order to obtain the HOMO-LUMO gap for further comparison with the theoretical results. The calculated values to the HOMO-LUMO gap are in excellent agreement with the experimental results, where the electronegativity of the heteroatom (O, S and Se) seems to play a fundamental role in the absorption maxima location. A theoretical study was performed using a DFT/B3LYP calculations with Becke's three-parameter hybrid method applying the Lee-Yang-Parr functional correlation (B3LYP) with DGDZVP basis set in order to evaluate some physical chemistry data related with mesomorphic and spectral electronic properties. By synthesizing these compounds we were able to get a more precise description about the influence of the chalcogen atom on the mesomorphic and photophysical properties. (author)
Walking Down the Chalcogenic Group of the Periodic Table: From Singlet to Triplet Organic Emitters.
Kremer, Adrian; Aurisicchio, Claudia; De Leo, Federica; Ventura, Barbara; Wouters, Johan; Armaroli, Nicola; Barbieri, Andrea; Bonifazi, Davide
2015-10-19
The synthesis, X-ray crystal structures, ground- and excited-state UV/Vis absorption spectra, and luminescence properties of chalcogen-doped organic emitters equipped on both extremities with benzoxa-, benzothia-, benzoselena- and benzotellurazole (1X and 2X ) moieties have been reported for the first time. The insertion of the four different chalcogen atoms within the same molecular skeleton enables the investigation of only the chalcogenic effect on the organisation and photophysical properties of the material. Detailed crystal-structure analyses provide evidence of similar packing for 2O -2Se , in which the benzoazoles are engaged in π-π stacking and, for the heavier atoms, in secondary X⋅⋅⋅X and X⋅⋅⋅N bonding interactions. Detailed computational analysis shows that the arrangement is essentially governed by the interplay of van der Waals and secondary bonding interactions. Progressive quenching of the fluorescence and concomitant onset of phosphorescence features with gradually shorter lifetimes are detected as the atomic weight of the chalcogen heteroatom increases, with the tellurium-doped derivatives exhibiting only emission from the lowest triplet excited state. Notably, the phosphorescence spectra of the selenium and tellurium derivatives can be recorded even at room temperature; this is a very rare finding for fully organic emitters. PMID:26471446
Zero Field Splitting of the chalcogen diatomics using relativistic correlated wave-function methods
Rota, Jean-Baptiste; Knecht, Stefan; Fleig, Timo;
2011-01-01
The spectrum arising from the (π*)2 configuration of the chalcogen dimers, namely the X21, a2 and b0+ states, is calculated using Wave-Function Theory (WFT) based methods. Two-component (2c) and four-component (4c) MultiReference Configuration Interaction (MRCI) and Fock-Space Coupled Cluster (FS...
Chalcogen height dependence of magnetism and Fermiology in FeTexSe1−x
The FeTexSe1−x (x = 0, 0.25, 0.50, 0.75 and 1) system has been studied using density functional theory. Our results show that for FeSe, the local density approximation (LDA) seems a better approximation in terms of magnitude of magnetic energy whereas the generalized gradient approximation (GGA) greatly overestimates it. On the other hand for FeTe, GGA is a better approximation that gives the experimentally observed magnetic state. It has been shown that the height of chalcogen atoms above Fe layers has a significant effect on band structure, electronic density of states (DOS) at the Fermi level N(EF) and Fermi surfaces. For FeSe the value of N(EF) is small so as to satisfy Stoner criteria for ferromagnetism, (I × N(EF) ≥ 1) whereas for FeTe, since the value of N(EF) is large, the same is close to being satisfied. Force minimization for FeTexSe1−x using the supercell approach shows that in a disordered system Se and Te do not share the same site and have two distinct z co-ordinates. This has a small effect on magnetic energy but no significant difference in band structure and DOS near EF when calculated using either the relaxed or average value of z for chalcogen atoms. Thus substitution of Se at the Te site decreases the average value of chalcogen height above Fe layers, which in turn affects the magnetism and Fermiology in the system. By using the coherent potential approximation for the disordered system, we found that height of chalcogen atoms above the Fe layer, rather than chalcogen species or disorder in the anion planes, affects the magnetism and shape of Fermi surfaces (FSs), thus significantly altering nesting conditions, which govern antiferromagnetic spin fluctuations in the system. (paper)
[Unilateral triangular lumbopelvic stabilization: indications and techniques].
Hoffmann, M F; Dudda, M; Schildhauer, T A
2013-11-01
Operative fixation has become treatment of choice for unstable sacral fractures. Osteosynthesis for these fractures results in loss of reduction in up to 15%. Vertical sacral fractures involving the S1 facet joint (Isler 2 and 3) may lead to multidirectional instability. Multidirectional instability of the posterior pelvic ring and lumbopelvic junction may be stabilized and forces balanced by a so-called lumbopelvic triangular fixation. Lumbopelvic triangular fixation combines vertical fixation between the lumbar vertebral pedicle and the ilium, with horizontal fixation, as an iliosacral screw or a transiliacal plate osteosynthesis. The iliac screw is directed from the posterior superior iliac spine (PSIS) to the anterior inferior iliac spine (AIIS). Thereby, lumbopelvic fixation decreases the load to the sacrum and SI joint and transfers axial loads from the lumbar spine directly onto the ilium. Triangular lumbopelvic fixation allows early full weight bearing and therefore reduces prolonged immobilization. The placement of iliac screws may be a complex surgical procedure. Thus, the technique requires thorough surgical preparation and operative logistics. Wound-related complications may occur. Preexisting Morell-Lavalée lesions increase the risk for infection. Prominent implants cause local irritation and pain. Hardware prominence and pain are markedly reduced with screw head recession into the PSIS. PMID:24233083
Teeter, Glenn; Du, Hui; Young, Matthew
2013-08-06
A method for synthesizing a thin film of copper, zinc, tin, and a chalcogen species ("CZTCh" or "CZTSS") with well-controlled properties. The method includes depositing a thin film of precursor materials, e.g., approximately stoichiometric amounts of copper (Cu), zinc (Zn), tin (Sn), and a chalcogen species (Ch). The method then involves re-crystallizing and grain growth at higher temperatures, e.g., between about 725 and 925 degrees K, and annealing the precursor film at relatively lower temperatures, e.g., between 600 and 650 degrees K. The processing of the precursor film takes place in the presence of a quasi-equilibrium vapor, e.g., Sn and chalcogen species. The quasi-equilibrium vapor is used to maintain the precursor film in a quasi-equilibrium condition to reduce and even prevent decomposition of the CZTCh and is provided at a rate to balance desorption fluxes of Sn and chalcogens.
Use of ionic liquids in synthesis of nanocrystals, nanorods and nanowires of elemental chalcogens
A Thirumurugan
2007-04-01
Nanocrystals of elemental chalcogens have been synthesized solvothermally by using elemental chalcogen powder (Se and Te) and NaBH4 in imidazolium[BMIM]-based ionic liquids as solvents at 180–200°C. Nanorods and nanowires of Se and Te have been obtained when polyethyleneglycol was used as a co-solvent. Se nanowires have been prepared by using an ionic liquid with a small amount of water at room temperature. Sulfur microspheres have been prepared by heating sulfur powder in a mixture of [BMIM][BF4] and polyethyleneglycol over the temperature range 150–250°C. The nanostructures obtained are single crystalline in all the cases.
Ultrasound fields from triangular apertures
Jensen, Jørgen Arendt
1996-01-01
The pulsed field from a triangular aperture mounted in an infinite, rigidbaffle is calculated. The approach of spatial impulse responses,as developed by Tupholme and Stepanishen, is used. By this both the emitted and received pulsed ultrasound field can be found for any transducerexcitation and...
On triangular algebras with noncommutative diagonals
2008-01-01
We construct a triangular algebra whose diagonals form a noncommutative algebra and its lattice of invariant projections contains only two nontrivial projections. Moreover we prove that our triangular algebra is maximal.
Shukla, Rahul; Chopra, Deepak
2016-05-18
In this article, we have analyzed the nature and characteristics of PSe noncovalent interactions by studying the effect of substitution on XH2PSeH2, H3PSeHX and XH2PSeHX (X= -H, -F, -CH3, -CF3, -Cl, -OH, -OCH3, -NH2, -NHCH3, and -CN) as our systems of interest at MP2/aug-cc-pVDZ level of theory. Binding energy calculations depict that binding energy increases in the order XH2PSeH2 < H3PSeHX < XH2PSeHX with the nature of the substituent having a direct effect on the strength of the interactions. PSe contacts as short as 2.52 Å were observed and analyzed in our study. The energy values for PSe contacts were found to exist in the range of -1.20 kcal mol(-1) to -7.89 kcal mol(-1). The topological analysis confirms the presence of PSe contacts in all the complexes with characteristics similar to hydrogen bonds. NBO analysis helped in categorizing these interactions into pnicogen and chalcogen bonds, depending on the strength of P(lp) to σ*(Se-X) orbitals or Se(lp) to σ*(P-X) orbitals. PMID:27145973
刘玉珂; 张敏; 张斌青; 郭会利; 陈伟; 杨静; 张国庆
2014-01-01
Objective To discuss the application value of weight-bearing MRI in the Diagnosis of injury of triangular fibrocartilage complex(TFCC) in the wrist. Mathods 22 cases with suspected injury of the triangular fibrocartilage complex were performed with conventional MR and weight-bearing MRI. 20 cases of them underwent arthroscopy. The findings of conventional MRI, weight-bearing MRI and arthroscopy were compared and analyzed. Results In 22 cases of injury of TFCC, 17 cases showed part tearing, including ulnar tearing in 12 cases, radius tear in 5 cases. Isointensity signal and High signal intensity of injury of TFCC were revealed on T1WI and T2WI respectively, and the injury range was no more than half of the TFCC. In weight-bearing MRI GE-STIR sequence, the signal is more higher and more limited than conventional MRI, and the boundary was more clear. The signal was more higher and the surrounding soft tissue edema showed more obvious. 5 cases showed complete tearing, and the shape was irregular and the signal was heterogeneously increased in conventional MRI. The shape was more irregular and the signal was higher in weight-bearing MRI, and the surrounding soft tissue edema was more obvious. 9 cases were associated with cystic fluid in the radius-ulnar joint. 8 cases were associated with dislocation of radius-ulnar joint, and 7 cases associated with ulnar-sided wrist impingement syndromes, and 4 cases associated with bone marrow edema of radius or ulnar. Conclusion Compared with conventional MRI, weight-bearing MRI could adequately reveal the injury of triangular fibrocartilage complex, and the combination of the two methods can improve the diagnostic accuracy of injury of TFCC.%目的：探讨负重位MRI在腕关节三角纤维软骨复合体（TFCC）损伤中的应用价值。方法搜集临床怀疑腕关节TFCC损伤的患者22例，均进行腕关节常规体位和负重位MRI扫描，其中20例行腕关节镜检查，对比分析TFCC常规体位与负重位
陈爽; 徐文东; 冯晓源
2008-01-01
Objective To compare direct magnetic resonance(MR)arthrography with arthroscopy of the wrist for evaluation of injury in the triangular fibrocartilage complex(TFCC).Methods Fourteen cases with suspicion of injury of triangular fibrocartilage complex were performed with conventional MR and direct MR arthrography,10 cases were done by arthroscopy.In the direct MR arthrography,needle placement was obtained using clinical landmark under sterile technique and fluoroscopy,intra-articular injection was performed at the radius-scaphoid space with 5-7 ml 0.3%mixture of Gadolinium (0.1 mmol/L)and saline(0.3 ml Gd-DTPA+100 ml saline).The findings of MRI and MR arthrography were analyzed with results of arthroscopy.Resuits (1)Among 14 cases with injury of TFCC,there were ulnar tear in 5cases,radius tear in 4 cases,complete tear in 5 cases(included 2 cases with long term rheumatoid).(2)High signal intensity and isointensity signal of injury of TFCC were revealed on STIR or T2 WI and T1 WIrespectively,normal hypointensity signal of the TFCC was partially or completely absent.Contrast media at the ulnar insertion(5 cases with ulnar tear)or radius attachment of the TFCC(4 cases with radius tear)were seen in the MR arthrography with difierent extent,5 cases with complete tear showed contrast media at the both ulnar insertion and radius attachment of the TFCC.The findings of MR arthrography were well corresponded with results of arthroscopy on the lesion site,including ulnar tear in 3 cases,radius tear in 4cases and complete tear in 3 cases.(3)Among 14 cases with TFCC,8 cases had dislocation of radius-ulnar joint,6 cases had bone contusion of radius or ulnar,synovial reaction was also clearly depicted on conventional MRI and direct MR arthrography in all cases.Conclusion Compared with results of arthroscopy,direct MR arthrography can adequately reveal the injury of the triangular fibrocartilage complex,synovial reaction and edema changes are depicted on conventional MRI.%目的 通
Householder triangularization of a quasimatrix
Trefethen, Lloyd N.
2008-01-01
A standard algorithm for computing the QR factorization of a matrix A is Householder triangularization. Here this idea is generalized to the situation in which A is a quasimatrix, that is, a “matrix” whose “columns” are functions defined on an interval [a,b]. Applications are mentioned to quasimatrix leastsquares fitting, singular value decomposition, and determination of ranks, norms, and condition numbers, and numerical illustrations are presented using the chebfun system.
钟敏之; 曾旭文; 梁治平
2010-01-01
Objective To explore the clinical application of MRI technology in the injury of triangular fibrocartilage complex and its ligament. Clear its value in clinical treatment.Methods Review 5 normal volunteer and 21 cases patien whom pain in wrist. Evaluate the sequence of GRE T2、SE T1、STIR and 3D dynamic scan in the wrist. Results MRI play the important role to evaluate the TFCC、scapholunate ligament (SLL), and lunotriquetral ligament(LTL).In 21 cases pain of wrist patien, there were 8 cases suffer TFCC tears. SLL injure in 4 cases and TLT injure in 2 cases. The fracture in the wrist bone are 5 case. Rheumatoid arthritis are 4 case, Ischemia necrosis 2case. Conclusion The wrist injure often with TFCC and ligament lesion, it worth pay attention to clinic. The structure of wrist is complex, for accurate dialogic,we must use multi sequence and many orientation to show the anatomic.%目的 探讨MRI技术在腕三角纤维软骨体其周围韧带损伤的临床应用,明确其临床治疗价值.方法 对5名正常腕关节志愿者及21名腕关节痛患者进行观察,使用GRE T2、SE T1及STIR检查序列及动态腕关节扫描对腕三角纤维软骨复合体形态进行评价.结果 MRI在评价三角纤维软骨、月三角韧带、舟月间韧带起重要作用.21例腕关节痛患者三角纤维软骨撕裂8例,腕部骨折7例,类风湿性关节炎4例.腕骨缺血性坏死2例.结论 腕关节慢性损伤常伴有TFCC损伤,值得临床重视.腕关节结构复杂,在检查过程中必须多序列,多方位结合以协助诊断.
Defect chemistry and chalcogen diffusion in thin-film Cu{sub 2}ZnSnSe{sub 4} materials
Harvey, Steven P.; Repins, Ingrid; Teeter, Glenn [National Renewable Energy Laboratory (NREL), 15013 Denver West Parkway, Golden, Colorado 80401 (United States)
2015-02-21
Selenium diffusion in polycrystalline thin-film Cu{sub 2}ZnSn(S,Se){sub 4} (CZTSe) on molybdenum-coated soda-lime glass substrates was investigated by in situ monitoring of the molybdenum back-contact resistance during high-temperature selenization treatments. In these measurements, selenium diffusion through the CZTSe layer results in conversion of the molybdenum layer to MoSe{sub 2}, increasing the sheet resistance of the film stack. By monitoring the rate of MoSe{sub 2} formation as a function of annealing temperature, an activation energy of 0.5 ± 0.1 eV has been measured for selenium diffusion in CZTSe. The partial pressure dependence of chalcogen diffusion suggests that chalcogen vacancies are not the defect controlling chalcogen diffusion in thin-film CZTSe.
The Dominant Role of Chalcogen Bonding in the Crystal Packing of 2D/3D Aromatics
Fanfrlík, Jindřich; Přáda, A.; Padělková, Z.; Pecina, Adam; Macháček, Jan; Lepšík, Martin; Holub, Josef; Růžička, A.; Hnyk, Drahomír; Hobza, Pavel
2014-01-01
Roč. 53, č. 38 (2014), s. 10139-10142. ISSN 1433-7851 R&D Projects: GA ČR GBP208/12/G016; GA ČR GAP208/10/2269 Grant ostatní: GA MŠk(CZ) ED2.1.00/03.0058; GA MŠk(CZ) ED1.1.00/02.0070; GA MŠk(CZ) LM2011033 Institutional support: RVO:61388963 ; RVO:61388980 Keywords : boranes * chalcogen bonds * crystal structures * sulfur * X-ray diffraction Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 11.261, year: 2014
Synthesis and crystal structure determination of Br2SeIBr polyhalogen–chalcogen
A A Alemi; E Solaimani
2004-06-01
In this paper polyhalogen–chalcogen Br2SeIBr was synthesized and the crystal structure was determined by single crystal X-ray diffraction method. This compound was prepared in the temperature range 150–50°C which was brownish-red in colour and crystallized in monoclinic crystal system and space group 21/c with four molecules per unit cell. Lattice parameters were: = 6.3711(1), = 6.7522(2), = 16.8850(5) Å, = = 90°, = 95·96°, = 722·45 Å3.
Lukasiewicz-like Triangular Subnorms
Petrík, Milan; Sarkoci, P.
Paris : Atlantis Press, 2015 - (Alonso, J.; Bustince, H.; Reformat, M.), s. 1100-1105 ISBN 978-1-5108-0807-2. - (Advances in Intelligent Systems Research. 89). [IFSA - EUSFLAT 2015. World Congress of the International Fuzzy Systems Association /16./, Conference of the European Society for Fuzzy Logic and Technology /9./. Gijón (ES), 30.06.2015-03.07.2015] R&D Projects: GA ČR GJ15-07724Y Grant ostatní: VEGA(SK) 2/0059/12 Institutional support: RVO:67985807 Keywords : positively cancellative * commutative semigroup * triangular subnorm * weakly cancellative Subject RIV: BA - General Mathematics
UWB Directive Triangular Patch Antenna
A. C. Lepage
2008-01-01
Full Text Available Compact directive UWB antennas are presented in this paper. We propose an optimization of the F-probe fed triangular patch antenna. The new design achieves an impedance bandwidth of 69% (3–6.15 GHz and presents good radiation characteristics over the whole impedance bandwidth. The average gain is 6.1 dB. A time-domain study has been performed to characterize the antenna behavior in case a UWB pulse is used. Finally, we propose an alternative solution to facilitate the manufacturing process using metallized foam technology. It also improves the robustness of the antenna as well as reducing its cost.
Single-crystal silicon was hyperdoped with sulfur, selenium, and tellurium using ion implantation and nanosecond laser melting. The hyperdoping of such chalcogen elements led to strong and wide sub-bandgap light absorption. Annealing the hyperdoped silicon, even at low temperatures (such as 200–400 °C), led to attenuation of the sub-bandgap absorption. To explain the attenuation process, we modeled it as chemical decomposition reaction from an optically absorbing structure to a non-absorbing structure. Attenuation of the experimental absorption coefficient was fit using the Arrhenius equation. From the fitted data, we extracted the reaction activation energies of S-, Se-, and T-hyperdoped silicon as 0.338 ± 0.029 eV, 0.471 ± 0.040 eV, and 0.357 ± 0.028 eV, respectively. We discuss these activation energies in terms of the bond energies of chalcogen–Si metastable bonds, and suggest that several high-energy interstitial sites, rather than substitutional sites, are candidates for the atomic structures that are responsible for the strong sub-bandgap absorption of chalcogen hyperdoped silicon
Wang, Ke-Fan [Institute for Computational Materials Science, School of Physics and Electronics, Henan University, Kaifeng 475004 (China); Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Shao, Hezhu [Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Liu, Kong; Qu, Shengchun, E-mail: qsc@semi.ac.cn, E-mail: wangyx@henu.edu.cn; Wang, Zhanguo [Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Wang, Yuanxu, E-mail: qsc@semi.ac.cn, E-mail: wangyx@henu.edu.cn [Institute for Computational Materials Science, School of Physics and Electronics, Henan University, Kaifeng 475004 (China)
2015-09-14
Single-crystal silicon was hyperdoped with sulfur, selenium, and tellurium using ion implantation and nanosecond laser melting. The hyperdoping of such chalcogen elements led to strong and wide sub-bandgap light absorption. Annealing the hyperdoped silicon, even at low temperatures (such as 200–400 °C), led to attenuation of the sub-bandgap absorption. To explain the attenuation process, we modeled it as chemical decomposition reaction from an optically absorbing structure to a non-absorbing structure. Attenuation of the experimental absorption coefficient was fit using the Arrhenius equation. From the fitted data, we extracted the reaction activation energies of S-, Se-, and T-hyperdoped silicon as 0.338 ± 0.029 eV, 0.471 ± 0.040 eV, and 0.357 ± 0.028 eV, respectively. We discuss these activation energies in terms of the bond energies of chalcogen–Si metastable bonds, and suggest that several high-energy interstitial sites, rather than substitutional sites, are candidates for the atomic structures that are responsible for the strong sub-bandgap absorption of chalcogen hyperdoped silicon.
Problems on triangular norms and related operators
Klement, E.P.; Mesiar, Radko; Pap, E.
2004-01-01
Roč. 23, č. 145 (2004), s. 471-479. ISSN 0165-0114 R&D Projects: GA ČR GA402/04/1026 Institutional research plan: CEZ:AV0Z1075907 Keywords : triangular norm * triangular conorm * aggregation operator Subject RIV: BA - General Mathematics Impact factor: 0.734, year: 2004
Spectral properties of random triangular matrices
Basu, Riddhipratim; Ganguly, Shirshendu; Hazra, Rajat Subhra
2011-01-01
We provide a relatively elementary proof of the existence of the limiting spectral distribution (LSD) of symmetric triangular patterned matrices and also show their joint convergence. We also derive the expressions for the moments of the LSD of the symmetric triangular Wigner matrix using properties of Catalan words.
谢仁国; 汤锦波; 唐天驷; 刘国峰; 王古衡; 张昌军; 刑树国
2011-01-01
Objective Ulnar side wrist pain is one of the commonest symptoms, mostly arised from the triangular fibrocartilage complex ( TFCC) injuries. Arthroscopy is considered as the golden standard for diagnosis of the wrist disorders, superior to the CT and MRI. The aim of this study is to observe the anatomic components of TFCC of the wrist morphologically and arthroscopically, and to obtain the accurate arthroscopic view by comparison. Methods Five fresh cadaver upper limbs were applied to observe distal aspect of TFCC by the routine radiocarpal approach and proximal aspect of TFCC hy a direct approach over the distal radioulnar joint. After arthroscopy and capsulotomy, The TFCC was exposed to examine its components visually, and to examine the corresponding sites under the arthroscope. TFCC was then detached from the distal ends of the radius and the ulna to measure its length and thickness. Results TFC was like a triangular disc , of which peripheral parts became thickened into the palmar radioulnar ligament ( PRU) and the dorsal radioulnar ligament ( DRU) . TFCC originated from the ulnar edge of distal radius. Its distal part inserted and surrounded the base of ulnar styloid process, and its proximal part inserted into the fovea of distal ulna. Compared with the morphological observations, the distal aspect of the TFCC originations was very smooth under the wrist arthroscope. There was no obvious distinction among TFC, PRU and DRU. The proximal aspect of TFCC seemed like an arc over the distal radius and the fovea. The round articular surface of the ulnar head and the sigmoid notch at ulnar side of the distal radius could be seen clearly. Conclusions Wrist arthrosopy is reliable to clarify the TFCC accurately, based on the anatomical and morphological guidance. The direct portal route over the distal radio-ulnar joint is availahle to observe the profound parts of PRU and DRU ligaments.%目的 观察腕尺侧三角纤维软骨复合体的大体结构和腕关节镜
Constructing parametric triangular patches with boundary conditions
Hui Liu; Jun Ma; Fuhua Cheng
2008-01-01
The problem of constructing a parametric triangular patch to smoothly connect three surface patches is studied. Usually, these surface patches are defined on different parameter spaces. Therefore, it is necessary to define interpolation conditions, with values from the given surface patches, on the boundary of the triangular patch that can ensure smooth transition between different parameter spaces. In this paper we present a new method to define boundary conditions. Boundary conditions defined by the new method have the same parameter space if the three given surface patches can be converted into the same form through affine transformation. Consequently, any of the classic methods for constructing functional triangular patches can be used directly to construct a parametric triangular patch to connect given surface patches with G continuity. The resulting parametric triangular patch preserves precision of the applied classic method.
Watching systems of triangular graphs
Maryam Roozbayani
2014-03-01
Full Text Available A watching system in a graph $G=(V, E$ is a set $W={omega_{1}, omega_{2}, cdots, omega_{k}}$, where $omega_{i}=(v_{i}, Z_{i}, v_{i}in V$ and $Z_{i}$ is a subset of closed neighborhood of $v_{i}$ such that the sets $L_{W}(v={omega_{i}: vin omega_{i}}$ are non-empty and distinct, for any $vin V$. In this paper, we study the watching systems of line graph $K_{n}$ which is called triangular graph and denoted by $T(n$. The minimum size of a watching system of $G$ is denoted by $omega(G$. We show that $omega(T(n=lceilfrac{2n}{3}rceil$.
徐静; 汤锦波; 贾中正; 谢仁国
2009-01-01
目的 研究在体前臂旋前、旋后不同运动范围内三角纤维软骨复合体(TFCC)深部和浅部纤维的运动学.方法 以螺旋CT扫描6名志愿者腕关节,分别获得前臂在旋前90°至旋后90°内每隔30°的运动范围内桡骨和尺骨远端图像,三维重建骨结构图像后经软件处理得到在腕关节旋前和旋后过程中,三角纤维软骨复合体深部、浅部纤维的长度变化.结果 前臂旋转运动中,旋前运动时TFCC背侧浅部纤维、掌侧深部纤维处于紧张状态,TFCC掌侧浅部纤维、背侧深部纤维处于放松状态.旋后运动时TFCC背侧浅部纤维、掌侧深部纤维处于放松状态,TFCC掌侧浅部纤维、背侧深部纤维则处于紧张状态.结论 前臂旋转运动过程中,掌背侧总同时有TFCC掌、背侧深部或浅部纤维处于紧张状态,维持了下尺桡关节的稳定性.%objective To investigate three-dimensional kinematics of the superficial and deep portion of triangular fibrocartilage complex (TFCC) in different parts of the forearm rotation.Methods Six wrists of 6 volunteers were used to obtain CT scans at different positions of the wrist.The wrists were scanned from 90°of pronation to 90°of supination at an interval of 30 degrees.The 3-dimensional radius and ulna were reconstructed with customized software and changes in length of the superficial and deep portion of TFCC during forearm rotation.Results In forearm pronation,the superficial dorsal portion and the deep palmar portion of the TFCC were tight.While the sperficial palmar portion and the deep dorsal potion of the TFCC were lax.In supination,the changes inlength of all these fibers were reverse.Conclusions In forearm rotation one portion fibers of dorsal TFCC and one portion fibers of palmar TFCC are tight,and this mechanism controls stability during DRUJ rotation.
Modulating the Electronic and Optical Properties of Tetragonal ZnSe Monolayers by Chalcogen Dopants.
Zhou, Jia; Li, Yang; Wu, Xiaohong; Qin, Wei
2016-07-01
The recently proposed three-atom-thick single-layer ZnSe sheet demonstrates a strong quantum confinement effect by exhibiting a large enhancement of band gap relative to the zinc blende (ZB) bulk phase. In this work, we aim at investigating the electronic and optical properties of this ultrathin tetragonal ZnSe single-layer sheet with various chalcogen dopant atoms, based on density functional theory (DFT). We find that these single-layer sheets with dopant atoms are still direct-band semiconductors with tunable band gaps, which can lead to strong light absorption and potential applications in solar energy harvesting. Theoretical optical absorbance results show that the S-doped ZnSe monolayer exhibits a higher absorption performance compared to other doped and undoped ZnSe monolayers. These findings pave a way for the modulation of novel ultrathin tetragonal ZnSe monolayers for a wealth of potential optoelectronic applications. PMID:26972924
Guo, Y.; Liu, D.; Robertson, J.
2015-04-01
It is predicted that Schottky barriers of the transition metal dichalcogenides MoSe2, MoTe2, WS2, WSe2, and WTe2 will suffer less from Fermi level pinning by chalcogen vacancies than does MoS2, because their vacancy formation energies are larger. The reduction in vacancy numbers will allow a greater degree of Schottky barrier height tuning by varying metal work function of the contacts in these compounds. The vacancy levels of WS2, WSe2 and MoSe2, and MoTe2 are also calculated to lie nearer midgap, so that ambipolar conduction will be easier in these compounds than in MoS2.
Highly Strained Heterocycles Constructed from Boron-Boron Multiple Bonds and Heavy Chalcogens.
Braunschweig, Holger; Constantinidis, Philipp; Dellermann, Theresa; Ewing, William C; Fischer, Ingo; Hess, Merlin; Knight, Fergus R; Rempel, Anna; Schneider, Christoph; Ullrich, Stefan; Vargas, Alfredo; Woollins, J Derek
2016-04-25
The reactions of a diborene with elemental selenium or tellurium are shown to afford a diboraselenirane or diboratellurirane, respectively. These reactions are reminiscent of the sequestration of subvalent oxygen and nitrogen in the formation of oxiranes and aziridines; however, such reactivity is not known between alkenes and the heavy chalcogens. Although carbon is too electronegative to affect the reduction of elements with lower relative electronegativity, the highly reducing nature of the B-B double bond enables reactions with Se(0) and Te(0) . The capacity of multiple bonds between boron atoms to donate electron density is highlighted in reactions where diborynes behave as nucleophiles, attacking one of the two Te atoms of diaryltellurides, forming salts consisting of diboratellurenium cations and aryltelluride anions. PMID:27027522
Pecina, Adam; Lepšík, Martin; Hnyk, Drahomír; Hobza, Pavel; Fanfrlík, Jindřich
2015-01-01
Roč. 119, č. 8 (2015), s. 1388-1395. ISSN 1089-5639 R&D Projects: GA ČR GBP208/12/G016; GA ČR GAP208/10/2269 Grant ostatní: GA MŠk(CZ) LM2011033; GA MŠk(CZ) ED2.1.00/03.0058; GA MŠk(CZ) ED1.1.00/02.0070 Institutional support: RVO:61388963 ; RVO:61388980 Keywords : intermolecular interaction energies * Kohn-Sham orbitals * halogen bond Subject RIV: CF - Physical ; Theoretical Chemistry; CA - Inorganic Chemistry (UACH-T) Impact factor: 2.693, year: 2014
Classification and MR imaging of triangular fibrocartilage complex lesions%三角纤维软骨复合体损伤的分型及磁共振表现
詹惠荔; 刘悦; 白荣杰; 钱占华; 叶薇; 李亚雄; 吴伯栋
2016-01-01
Objective To explore the MRI characteristics of injuries of triangular fibrocartilage complex (TFCC),and provide imaging basis for the early diagnosis and treatment of the injuries.Methods A total of 10 healthy volunteers without wrist injuries and 200 patients from Beijing Jishuitan Hospital who complained ulnar-sided wrist pain and were highly suspected as the injury of TFCC underwent the wrist magnetic resonance examination.All subjects were in a prone position and underwent examination on coronal T1 WI scan and PD-FS on 3 planes respectively.Then the MRI characteristics of 3 healthy volunteers and 67 patients with TFCC injuries that confirmed by operation were analyzed.According to the comparative analysis of normal anatomy and Palmer classification,the injuries were classified and MRI features of different types of injuries were analyzed.At last,imaging findings were compared with surgical results.Results Three healthy volunteers without injuries showed mainly in low signal intensity on T1WI and PD-FS images.According to Palmer classification,there were 52 traumatic injuries (Ⅰ A 9,Ⅰ B 25,Ⅰ C 3,Ⅰ D 13,In addition,1 has central perforation and ulnar avulsion and 1 has ulnar and radial injuries simultaneously) and 15 degenerative injuries (Ⅱ A 5,Ⅱ B 1,ⅡC 2,Ⅱ D 1,Ⅱ E 6) among 67 patients.The central perforation mainly demonstrated as linear high signal perpendicular to the disk,and run in a sagittal line.The ulnar,distal,and radial avulsion mainly showed the injuries were irregular,the structures were ambiguous,and there was high signal intensity in the injured structures on PD-FS.Degenerative injuries demonstrated the irregularity of TFC and heterogeneous signals on PD-FS.There were mixed intermediate-high signals and changes in the articular cartilage of lunate and ulna,high signal in the lunotriquetral ligament and ulnocarpal or radioulnar arthritis.Conclusion MRI can demonstrate the anatomy of TFCC accurately,evaluate and make the general
Kadlag, Yogita; Becker, Harry
2016-04-01
187Re-187Os systematics, abundances of highly siderophile elements (HSE: Re, PGE, and Au), chalcogen elements (Te, Se, and S), and some major and minor elements were determined in physically separated components of the Allende (CV3) and Murchison (CM2) carbonaceous chondrites. Substantial differences exist in the absolute and relative abundances of elements in the components, but the similarity of calculated and literature bulk rock abundances of HSE and chalcogens indicate that chemical complementarity exists among the components, with CI chondrite-like ratios for many elements. Despite subsequent alteration and oxidation, the overall cosmochemical behavior of most moderately to highly siderophile elements during high-temperature processing has been preserved in components of Allende at the sampling scale of the present study. The 187Re-187Os systematics and element variations of Allende are less disturbed compared with Murchison, which reflects different degrees of oxidation and alteration of these meteorites. The HSE systematics (with the exception of Au) is controlled by two types of materials: Pd-depleted condensates and CI chondrite-like material. Enrichment and heterogeneous distribution of Au among the components is likely the result of hydrothermal alteration. Chalcogen elements are depleted compared with HSE in all components, presumably due to their higher volatility. Small systematic variations of S, Se, and Te in components bear the signature of fractional condensation/partial evaporation and metal-sulfide-silicate partitioning.
A Critical Path Problem Using Intuitionistic Triangular Fuzzy Number
P.JAYAGOWRI
2014-05-01
Full Text Available Critical path method is a network based method planned for development and organization of complex project in real world application. In this paper, a new methodology has been made to find the critical path in a directed acyclic graph, whose activity time uncertain. The vague parameters in the network are represented by intuitionistic triangular fuzzy numbers, instead of crisp numbers. A new procedure is proposed to find the optimal path, and finally illustrative examples is provided to validate the proposed approach.
Honeycomb and triangular domain wall networks in heteroepitaxial systems
Elder, K. R.; Chen, Z.; Elder, K. L. M.; Hirvonen, P.; Mkhonta, S. K.; Ying, S.-C.; Granato, E.; Huang, Zhi-Feng; Ala-Nissila, T.
2016-05-01
A comprehensive study is presented for the influence of misfit strain, adhesion strength, and lattice symmetry on the complex Moiré patterns that form in ultrathin films of honeycomb symmetry adsorbed on compact triangular or honeycomb substrates. The method used is based on a complex Ginzburg-Landau model of the film that incorporates elastic strain energy and dislocations. The results indicate that different symmetries of the heteroepitaxial systems lead to distinct types of domain wall networks and phase transitions among various surface Moiré patterns and superstructures. More specifically, the results show a dramatic difference between the phase diagrams that emerge when a honeycomb film is adsorbed on substrates of honeycomb versus triangular symmetry. It is also shown that in the small deformation limit, the complex Ginzburg-Landau model reduces to a two-dimensional sine-Gordon free energy form. This free energy can be solved exactly for one dimensional patterns and reveals the role of domains walls and their crossings in determining the nature of the phase diagrams.
Fluid Flow Through Triangular and Square Cylinders
Salam, Nasaruddin
2014-01-01
Characteristicsof fluid flowing through triangular and square cylindershas been analyzed experimentally andnumerically by CFDat Reynolds number based on square cylinders diameter,Re = 14.730;26.040 and 37.192. Ratio of the distance between cylinders to square cylinders diameter (L/D) was variedas0.0;1.0; 2.0; 3.0; 4.0; and 5.0 while ratio of the triangular cylinders diameter to square cylinders diameter (d/D) was constant at 0.5. The results showed that the vortex is damped...
Sharma, Subash; Kalita, Golap; Vishwakarma, Riteshkumar; Zulkifli, Zurita; Tanemura, Masaki
2015-01-01
In-plane heterostructure of monolayer hexagonal boron nitride (h-BN) and graphene is of great interest for its tunable bandgap and other unique properties. Here, we reveal a H2-induced etching process to introduce triangular hole in triangular-shaped chemical vapor deposited individual h-BN crystal. In this study, we synthesized regular triangular-shaped h-BN crystals with the sizes around 2-10 μm on Cu foil by chemical vapor deposition (CVD). The etching behavior of individual h-BN crystal w...
Solutions to the Triangular Bicycle Flags Problem
Hartweg, Kim
2005-01-01
Students in a fifth-grade general education class and a second-grade gifted class participated in the Triangular Bicycle Flags problem. The results indicated that providing students with geometric experiences at the correct van Hiele level is necessary for helping students move from one level of understanding to the next.
Basic Employability Skills: A Triangular Design Approach
Rosenberg, Stuart; Heimler, Ronald; Morote, Elsa-Sofia
2012-01-01
Purpose: This paper seeks to examine the basic employability skills needed for job performance, the reception of these skills in college, and the need for additional training in these skills after graduation. Design/methodology/approach: The research was based on a triangular design approach, in which the attitudes of three distinct groups--recent…
Chalcogenation of the 1,4-C2P4 ring: oxidation, isomerization, insertion, and ring contraction.
Elder, Philip J W; Chivers, Tristram
2013-07-01
The reaction of H2C(PCl2)2 with 4 equiv of (t)BuMgCl in tetrahydrofuran (THF) produces 1,4-(CH2)2(P(t)Bu)4, 1, in about 65% yield. This six-membered ring reacts directly with elemental sulfur or selenium in toluene at low temperatures to give the mono- and dichalcogenides 1,4-(CH2)2(P(t)BuE)(P(t)Bu)3 (E = S, 2a, E = Se, 2b) and 1,4-(CH2)2-2,5-(P(t)BuE)2(P(t)Bu)2 (E = S, 3a, E = Se, 3b). X-ray structural determinations showed that 3a and 3b are isostructural in the solid state; the six-membered C2P4 ring exhibits a twist-boat geometry with chalcogen substituents in syn positions in each case. Density functional theory (DFT) calculations for the three possible isomers of disubstitution were performed to elucidate the factors that favor the 2,5-isomer. Thermal isomerism was observed in solutions of 3b or 3a in toluene at 60 and 95 °C, respectively, to give the corresponding 2,6-isomers. With an excess of chalcogen in toluene at reflux, the four-membered rings (H2C)(P(t)BuE)2E (E = S, 4a, E = Se, 4b) were obtained and identified by multinuclear NMR spectroscopy and single crystal X-ray crystallography, which showed the (t)Bu groups in a trans orientation with respect to the CP2E ring. With a large excess of chalcogen, the five-membered rings (H2C)(P(t)BuE)2E2 (E = S, 5a, E = Se, 5b) were also observed; the X-ray structure of 5b revealed a half-envelope conformation for the CP2Se2 ring. The direct reaction of 4a with sulfur in boiling toluene does not produce 5a, whereas 5b is formed slowly and in low yields from 4b and selenium under similar conditions. On the basis of DFT calculations of the relative energies of likely intermediates, chalcogen insertion into the P-P bonds of 3a and 3b to give eight-membered C2P4E2 rings, followed by monomerization, is proposed as a feasible pathway for the formation of the four-membered CP2E heterocycles 4a and 4b. PMID:23786389
Linear Maps Preserving Idempotency of Products of Matrices on Upper Triangular Matrix Algebras
QI JING; JI GUO-XING
2009-01-01
. Let Tn be the algebra of all n × n complex upper triangular matrices. We give the concrete forms of linear injective maps on Tn which preserve the nonzero idempotency of either products of two matrices or triple Jordan products of two matrices.
Santosh K Sahoo
2015-12-01
A relative synthetic strategy toward intermolecular oxidative C−Chalcogen bond formation of alkanes has been illustrated using both Cu(II) assisted Cu(II) free conditions. This led to construction of a comparative study of hydrocarbon benzylic and 2°/3°-cycloalkyl moieties bond sulfenylation and selenation protocol by the chalcogen sources, particularly sulfur and selenium, respectively. In addition, this protocol disclosed the auspicious formation of sp3C−S coupling products over leading the sp3C−N coupling products by using 2-mercaptobenzothiazole (MBT) substrates.
Triangular de Rham cohomology of compact Kahler manifolds
The de Rham H1DR(M,G) of a smooth manifold M with values in a group Lie G is studied. By definition, this is the quotient of the set of flat connections in the trivial principal bundle MxG by the so-called gauge equivalence. The case under consideration is the one when M is a compact Kahler manifold and G is a soluble complex linear algebraic group in a special class containing the Borel subgroups of all complex classical groups and, in particular, the group of all triangular matrices. In this case a description of the set H1DR(M,G) in terms of the cohomology of M with values in the (Abelian) sheaves of flat sections of certain flat Lie algebra bundles with fibre g (the tangent Lie algebra of G) or, equivalently, in terms of the harmonic forms on M representing this cohomology is obtained
Triangular Geometrized Sampling Heuristics for Fast Optimal Motion Planning
Ahmed Hussain Qureshi
2015-02-01
Full Text Available Rapidly-exploring Random Tree (RRT-based algorithms have become increasingly popular due to their lower computational complexity as compared with other path planning algorithms. The recently presented RRT* motion planning algorithm improves upon the original RRT algorithm by providing optimal path solutions. While RRT determines an initial collision-free path fairly quickly, RRT* guarantees almost certain convergence to an optimal, obstacle-free path from the start to the goal points for any given geometrical environment. However, the main limitations of RRT* include its slow processing rate and high memory consumption, due to the large number of iterations required for calculating the optimal path. In order to overcome these limitations, we present another improvement, i.e, the Triangular Geometerized-RRT* (TGRRT* algorithm, which utilizes triangular geometrical methods to improve the performance of the RRT* algorithm in terms of the processing time and a decreased number of iterations required for an optimal path solution. Simulations comparing the performance results of the improved TG-RRT* with RRT* are presented to demonstrate the overall improvement in performance and optimal path detection.
Triangular Ising antiferromagnets with quenched nonmagnetic impurities.
Tang, Huai-Lei; Zhu, Yi; Yang, Guo-Hong; Jiang, Ying
2010-05-01
In a random spin system, the cooperation of randomness and frustration will lead to a spin-glass phase. However, in geometrically frustrated spin systems, quenched nonmagnetic impurities lift frustration locally. This makes randomness and frustration in these systems as competitors rather than cooperators. By mapping the dilute triangular Ising antiferromagnetic system to elastic array of noncrossing strings, we find that the nonmagnetic impurities in the spin system play roles of pinning centers in the string system. Calculation shows that in the ground state of this system, the spin-glass correlation is power-law decayed, quite different from the standard behavior of spin glass in which spin-glass correlation between two spins at infinite distance tends to a finite value. This indicates that triangular Ising antiferromagnets with quenched nonmagnetic impurities cannot be a spin glass. Instead, in the ground states, they present properties of vortex glass. PMID:20866185
Transport Properties for Triangular Barriers in Graphene
Mouhafid, Abderrahim El; Jellal, Ahmed
2013-01-01
We theoretically study the electronic transport properties of Dirac fermions through one and double triangular barriers in graphene. Using the transfer matrix method, we determine the transmission, conductance and Fano factor. They are obtained to be various parameters dependent such as well width, barrier height and barrier width. Therefore, different discussions are given and comparison with the previous significant works is done. In particular, it is shown that at Dirac point the Dirac fer...
Human resource management in triangular employment relationships
Fontinha, Ana Rita Ramos
2013-01-01
This dissertation concerns the triangular employment relationships of agency workers and outsourced workers. In particular, the aim was to investigate the relationship between employees’ perceptions and attributions of human resource management (HRM) practices and their dual affective organisational commitment, i.e., their commitment towards both the agency/outsourcer and the client organisation. We developed three empirical studies. In the first study, we found that commitmentfocused HRM att...
Block Triangular Preconditioning for Stochastic Galerkin Method
Zheng, Bin; Lin, Guang; Xu, Jinchao
2013-01-01
In this paper we study fast iterative solvers for the large sparse linear systems resulting from the stochastic Galerkin discretization of stochastic partial differential equations. A block triangular preconditioner is introduced and applied to the Krylov subspace methods, including the generalized minimum residual method and the generalized preconditioned conjugate gradient method. This preconditioner utilizes the special structures of the stochastic Galerkin matrices to achieve high efficie...
Optimization Bicriteria Linear Programming Constraint Fuzzy Triangular
Pratama, Lintang Gilang
2014-01-01
This final project is to make a algorithm Bicriteria Linear Programming with constraint is triangular fuzzy number. The method used in this research is download-right defuzzyfication bicriteria linear programming problems with fuzzy rules in fuzzy sets and fuzzy number operations. Resolving sub-bicriteria problem of fuzzy linear programming with Parametric Simplex Algorithm in which every constraint has become a firm number and efficient (optimum) result is the form of best eff...
Vertex-Atom-Dependent Rectification in Triangular h-BNC/Triangular Graphene Heterojunctions
Wang, Lihua; Zhao, Jianguo; Zhang, Zizhen; Ding, Bingjun; Guo, Yong
2016-08-01
First-principles calculations have shown dramatically unexpected rectifying regularities in particular heterojunction configurations with triangular hexagonal boron-nitride-carbon ( h-BNC) and triangular graphene (TG) sandwiched between two armchair graphene nanoribbon electrodes. When the triangular h-BNC and TG are linked by vertex atoms of nitrogen and carbon (boron and carbon), forward (reverse) rectifying performance can be observed. Moreover, for a certain linking mode, the larger the elemental proportion p (where p = N_{{{boron}} + {{nitrogen}}} /N_{{{boron}} + {{nitrogen}} + {{carbon}}} ) in the h-BNC, the larger the ratio for forward (reverse) rectification. A mechanism for these rectification behaviors is suggested. The findings provide insights into control of rectification behaviors in TG-based nanodevices.
Thermodynamic Properties in Triangular-Lattice Superconductors
Ma, Xixiao; Qin, Ling; Zhao, Huaisong; Lan, Yu; Feng, Shiping
2016-06-01
The study of superconductivity arising from doping a Mott insulator has become a central issue in the area of superconductivity. Within the framework of the kinetic-energy-driven superconducting (SC) mechanism, we discuss the thermodynamic properties in the triangular-lattice cobaltate superconductors. It is shown that a sharp peak in the specific heat appears at the SC transition temperature T_c, and then the specific heat varies exponentially as a function of temperature for temperatures Tqualitatively the Bardeen-Cooper-Schrieffer-type temperature dependence, and has the same dome-shaped doping dependence as T_c.
Parameterization of triangular meshes for texture mapping
Leksell, Mats
2008-01-01
A parameterization of a three-dimensional triangular mesh M to a two dimensional parameter domain is a invertibel PM : S - R, where is the set of all points on the surface. one of the use for such a mapping is for mapping an image from the parameter space D-R onto S. thesis evalutes several apporaches for creating such a mapping. for this purpos , the optimal mapping is an isomtry, i.e. a mapping that preserves the length of all the edges. Such a mapping is however often impossible or somputa...
Theory of a triangular micro-robot
Vladimirov, Vladimir A
2012-01-01
In this paper we study the self-propulsion of a triangular micro-robot (or triangle-robot) which consists of three spheres connected by three rods; the rods' lengths are changing independently and periodically. Using the asymptotic procedure containing the two-timing method and distinguished limit arguments, we obtain analytic expressions for self-propulsion velocity the angular velocity. Our calculations show that a triangle-robot rotates with constant angular velocity around its centroid, while the centroid moves in a circle. The important special case of zero angular velocity represents rectilinear translational self-propulsion with constant velocity.
An Improved Triangular Element With Drilling Rotations
Damkilde, Lars; Grønne, Mikael
2002-01-01
A new plane element with rotational degrees in the corner nodes is presented. The element has 12 degrees of freedom and the only difference from the well-known Linear Strain Triangular (LST) element is that the displacements perpendicular to the element sides in the mid-side nodes are replaced by...... rotations in the corner nodes. Compared to Allman's plane element which was the first succesfull implementation of drilling rotations the proposed element has extra displacements in the mid-side nodes parallel to the element sides. The performance should therefore be better and closer to the LST...
Natural elongation and triangularity of tokamak equilibria
Quasianalytic formulas are calculated for the elongation κ and triangularity δ of the plasma surface of a free-boundary tokamak equilibrium. The final results give κ and δ as functions of five quantities: the inverse aspect ratio ε, the poloidal beta βp, the internal inductance li, and the quadrupole and hexapole moments of the externally applied field. The agreement with numerically computed equilibria is found to be quite good when A≥3, κ≤1.5, and δ≤0.2 and when the plasma is limited by the vacuum vessel wall and not diverted by the presence of a separatrix on the plasma surface
Reproducible Triangular Solvers for High-Performance Computing
Iakymchuk, Roman; Defour, David; Collange, Sylvain; Graillat, Stef
2015-01-01
On modern parallel architectures, floating-point computations may become non-deterministic and, therefore, non-reproducible mainly due to non-associativity of floating-point operations. We propose an algorithm to solve dense triangular systems by leveraging the standard parallel triangular solver and our, recently introduced, multi-level exact summation approach. Finally, we present implementations of the proposed fast repro-ducible triangular solver and results on recent NVIDIA GPUs.
Use of dermoscopy in the diagnosis of temporal triangular alopecia *
de Campos, Jullyene Gomes; Oliveira, Cláudia Marina Puga Barbosa; Romero, Sandra Adolfina Reyes; Klein, Ana Paula; Akel, Patricia Bandeira de Melo; Pinto, Giselle Martins
2015-01-01
Temporal triangular alopecia, also referred as congenital triangular alopecia, is an uncommon dermatosis of unknown etiology. It is characterized by a non-scarring, circumscribed alopecia often located unilaterally in the frontotemporal region. It usually emerges at ages 2-9 years. Alopecia areata is the main differential diagnosis, especially in atypical cases. Dermoscopy is a noninvasive procedure that helps distinguish temporal triangular alopecia from aloepecia areata. Such procedure prev...
Chalcogen doping at anionic site: A scheme towards more dispersive valence band in CuAlO2
Mazumder, Nilesh; Sen, Dipayan; Chattopadhyay, Kalyan Kumar
2013-02-01
Using first-principles calculations, we propose to enhance the dispersion of the top of valence band at high-symmetry points by selective introduction of chalcogen (Ch) impurities at oxygen site. As ab-plane hole mobility of CuAlO2 is large enough to support a band-conduction model over a polaronic one at room temperature [M. S. Lee et al. Appl. Phys. Lett. 79, 2029, (2001); J. Tate et al. Phys. Rev. B 80, 165206, (2009)], we examine its electronic and optical properties normal to c-axis. Intrinsic indirectness of energy-gap at Γ-point can be effectively removed along with substantial increase in density of states near Fermi level (EF) upon Ch addition. This can be attributed to S 2p-Cu 3d interaction just at or below EF, which should result in significantly improved carrier mobility and conductivity profile for this important p-type TCO.
Ultracold quantum gases in triangular optical lattices
Becker, C; Kronjäger, J; Dörscher, S; Bongs, K; Sengstock, K
2009-01-01
Over the last years the exciting developments in the field of ultracold atoms confined in optical lattices have led to numerous theoretical proposals devoted to the quantum simulation of problems e.g. known from condensed matter physics. Many of those ideas demand for experimental environments with non-cubic lattice geometries. In this paper we report on the implementation of a versatile three-beam lattice allowing for the generation of triangular as well as hexagonal optical lattices. As an important step the superfluid-Mott insulator (SF-MI) quantum phase transition has been observed and investigated in detail in this lattice geometry for the first time. In addition to this we study the physics of spinor Bose-Einstein condensates (BEC) in the presence of the triangular optical lattice potential, especially spin changing dynamics across the SF-MI transition. Our results suggest that below the SF-MI phase transition, a well-established mean-field model describes the observed data when renormalizing the spin-d...
Ultracold quantum gases in triangular optical lattices
Over recent years, exciting developments in the field of ultracold atoms confined in optical lattices have led to numerous theoretical proposals devoted to the quantum simulation of problems e.g. known from condensed matter physics. Many of those ideas demand experimental environments with non-cubic lattice geometries. In this paper, we report on the implementation of a versatile three-beam lattice allowing for the generation of triangular as well as hexagonal optical lattices. As an important step, the superfluid-Mott insulator (SF-MI) quantum phase transition has been observed and investigated in detail in this lattice geometry for the first time. In addition to this, we study the physics of spinor Bose-Einstein condensates (BEC) in the presence of the triangular optical lattice potential, especially spin changing dynamics across the SF-MI transition. Our results suggest that, below the SF-MI phase transition, a well-established mean-field model describes the observed data when renormalizing the spin-dependent interaction. Interestingly, this opens up new perspectives for a lattice-driven tuning of a spin dynamics resonance occurring through the interplay of the quadratic Zeeman effect and spin-dependent interaction. Finally, we discuss further lattice configurations that can be realized with our setup.
Ultracold quantum gases in triangular optical lattices
Becker, C; Soltan-Panahi, P; Doerscher, S; Sengstock, K [Institut fuer Laserphysik, Universitaet Hamburg, Hamburg D-22761 (Germany); Kronjaeger, J; Bongs, K, E-mail: cbecker@physnet.uni-hamburg.d [MUARC, School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)
2010-06-15
Over recent years, exciting developments in the field of ultracold atoms confined in optical lattices have led to numerous theoretical proposals devoted to the quantum simulation of problems e.g. known from condensed matter physics. Many of those ideas demand experimental environments with non-cubic lattice geometries. In this paper, we report on the implementation of a versatile three-beam lattice allowing for the generation of triangular as well as hexagonal optical lattices. As an important step, the superfluid-Mott insulator (SF-MI) quantum phase transition has been observed and investigated in detail in this lattice geometry for the first time. In addition to this, we study the physics of spinor Bose-Einstein condensates (BEC) in the presence of the triangular optical lattice potential, especially spin changing dynamics across the SF-MI transition. Our results suggest that, below the SF-MI phase transition, a well-established mean-field model describes the observed data when renormalizing the spin-dependent interaction. Interestingly, this opens up new perspectives for a lattice-driven tuning of a spin dynamics resonance occurring through the interplay of the quadratic Zeeman effect and spin-dependent interaction. Finally, we discuss further lattice configurations that can be realized with our setup.
The Geometric Continuity of Rational Bezier Triangular Surfaces
田捷
1991-01-01
The problems of geometric continuity for rational Bezier surfaces are discussed.Concise conditions of first order and second order geometric continuity for rational triangular bezier surfaces are given.Meanwhile,a geometric condition for smoothness between adjacent rational bezier surfaces and the transformation formulae between rational triangular patches and rational rectangular patches are obtained.
Sznajd Sociophysics Model on a Triangular Lattice
Chang, Iksoo
The Sznajd sociophysics model is generalized on the triangular lattice with pure antiferromagnetic opinion and also with both ferromagnetic and antiferromagnetic opinions. The slogan of the trade union ``united we stand, divided we fall'' can be realized via the propagation of ferromagnetic opinion of adjacent people in the union, but the propagation of antiferromagnetic opinion can be observed among the third countries between two big super powers or among the family members of conflicting parents. Fixed points are found in both models. The distributions of relaxation time of the mixed model are dispersed and become closer to log-normal as the initial concentration of down spins approaches 0.5, whereas for pure antiferromagnetic spins, they are collapsed into one master curve, which is roughly log-normal. We do not see the phase transition in the model.
Triangularity effects on the collisional diffusion for elliptic tokamak plasma
In this conference the effect of ellipticity and triangularity will be analyzed for axisymmetric tokamak in the collisional regime. Analytic forms for the magnetic field cross sections are taken from those derived recently by other authors [1,2]. Analytical results can be obtained in elliptic plasmas with triangularity by using an special system of tokamak coordinates recently published [3-5]. Our results show that triangularities smaller than 0.6, increases confinement for ellipticities in the range 1.2 to 2. This behavior happens for negative and positive triangularities; however this effect is stronger for positive than for negative triangularities. The maximum diffusion velocity is not obtained for zero triangularity, but for small negative triangularities. Ellipticity is also very important in confinement, but the effect of triangularity seems to be more important. High electric inductive field increases confinement, though this field is difficult to modify once the tokamak has been built. The analytic form of the current produced by this field is like that of a weak Ware pinch with an additional factor, which weakens the effect by an order of magnitude. The dependence of the triangularity effect with the Shafranov shift is also analyzed. References 1. - L. L. Lao, S. P. Hirshman, and R. M. Wieland, Phys. Fluids 24, 1431 (1981) 2. - G. O. Ludwig, Plasma Physics Controlled Fusion 37, 633 (1995) 3. - P. Martin, Phys. Plasmas 7, 2915 (2000) 4. - P. Martin, M. G. Haines and E. Castro, Phys. Plasmas 12, 082506 (2005) 5. - P. Martin, E. Castro and M. G. Haines, Phys. Plasmas 12, 102505 (2005)
Some Observations on Characteristics of China-U.S.-Russia Triangular Relationship
Li; Xing
2014-01-01
The China-U.S.-Russia triangular relationship emerged in the 1970s~90s, and is still in existence, but only the era environment and conditions, the compared strength between three countries, the impact scope and degree have changed. This triangular relationship is one of the world’s most complex, the most delicate and the most important. The Sino-U.S. relations and Sino-Russian relations are the most important bilateral relationships for China. As China upgrades its strategic and coordinate partnership with Russia, it also energetically promotes strategic-oriented relationship with the United States, namely, in the aspect of high politics, developing the strategic and coordinate relations with Russia, while in the aspect of low politics, developing mutually beneficial and win-win cooperation with the United States.
Logical, algebraic, analytic and probabilistic aspects of triangular norms
Klement, Erich Peter
2005-01-01
This volume gives a state of the art of triangular norms which can be used for the generalization of several mathematical concepts, such as conjunction, metric, measure, etc. 16 chapters written by leading experts provide a state of the art overview of theory and applications of triangular norms and related operators in fuzzy logic, measure theory, probability theory, and probabilistic metric spaces.Key Features:- Complete state of the art of the importance of triangular norms in various mathematical fields- 16 self-contained chapters with extensive bibliographies cover both the theoretical ba
Optimization of Multi-band Rectangular-Triangular Slotted Antenna
K.swetha,
2015-03-01
Full Text Available A multi-band microstrip patch antenna is developed and presented in this paper. The radiating elements in this antenna are composed of rectangular and triangular slots. These slots are engraved in the rectangular and triangular patch, joined together in one structure, and by single probe feed. The rectangular and triangular slots make the antenna to operate at multiband with relatively high gain. Therefore, this antenna can be used for wireless communication applications like WLAN, WiMax and radar system applications.
Electro-osmotic flows inside triangular microchannels
This work presents a numerical investigation of both pure electro-osmotic and combined electro-osmotic/pressure-driven flows inside triangular microchannels. A finite element analysis has been adopted to solve the governing equations for the electric potential and the velocity field, accounting for a finite thickness of the electric double layer. The influence of non-dimensional parameters such as the aspect ratio of the cross-section, the electrokinetic diameter and the ratio of the pressure force to the electric force on the flow behavior has been investigated. Numerical results point out that the velocity field is significantly influenced by the aspect ratio of the cross section and the electrokinetic diameter. More specifically, the aspect ratio plays an important role in determining the maximum volumetric flow rate, while the electrokinetic diameter is crucial to establishing the range of pressures that may be sustained by the electro-osmotic flow. Numerical results are also compared with two correlations available in the literature which enable to assess the volumetric flow rate and the pressure head for microchannels featuring a rectangular, a trapezoidal or an elliptical cross-section.
Triangular lattice arrays for interstitial microwave hyperthermia
Implantable miniature microwave antennas operating between 300 and 2450 MHz have been employed to heat deep-seated tumors in hyperthermia cancer therapy. While the complete response rate has been reported to be as high as 80%, a major limitation of this procedure is that present antennas tend to give allow heating zone near the tip of the device. Thus, there is considerable interest in antennas with improved heating at the tip of the interstitial hyperthermia applicator. Previously, the authors reported microwave antennas for interstitial hyperthermia and thermocoagulation with maximal power deposition occurring near the tip of the antenna. Experimental results obtained at phantom measurements showed that heating peaks near the tip of the antenna. Indeed, power deposition was enhanced by six to ten times. In this paper, they report the development of a novel interstitial array configuration for use at 915 and 2450 MHz that better conforms to accessible, deep-seated tumor volume. It is based on the unique configuration of an equilateral triangle. The symmetry afforded by locating three identical interstitial antennas at the corners of the triangle will allow the triangular array geometry to serve as a basic building block with which to construct lattice array structures to effect uniform heating throughout the three-dimensional volume of the tumor
Final critical habitat for Triangular Kidneyshell (Ptychobranchus greenii)
US Fish and Wildlife Service, Department of the Interior — This Polygon shapefile of critical habitat for the Triangular Kidneyshell (Ptychobranchus greenii) based on the description provided in the Federal Register.
Magnetoresistance measurement of permalloy thin film rings with triangular fins
Magnetization reversals in permalloy rings controlled by nucleation sites using triangular fins at the same side and diagonal with respect to the field direction are demonstrated by magnetoresistance measurement and micromagnetic simulation. In the ring with triangular fins at the same side, there exists two-step reversal from onion to flux-closure state (or vortex state) and then from flux-closure (or vortex state) to reverse onion state; in the ring with diagonal triangular fins, one-step reversal occurs directly from onion to reverse onion state. The reversal processes are repeatable and controllable in contrast to an ideal ring without triangular fins where one-step and two-step reversals occur randomly in sweep-up and sweep-down processes.
Bhattacharya, Kisholoy; Maity, Manoranjan; Abtab, Sk Md Towsif; Majee, Mithun Chandra; Chaudhury, Muktimoy
2013-08-19
A new family of trinuclear homo- and heterometal complexes with a triangular [V(V)O-MO-V(V)O] (M = V(IV), 1 and 2; Re(V), 3] all-oxido-metal core have been synthesized following a single-pot protocol using compartmental Schiff-base ligands, N,N'-bis(3-hydroxysalicylidene)-diiminoalkanes/arene (H4L(1)-H4L(3)). The upper compartment of these ligands with N2O2 donor combination (Salen-type) contains either a V(IV) or a Re(V) center, while the lower compartment with O4 donor set accommodates two V(V) centers, stabilized by a terminal and a couple of bridging methoxido ligands. The compounds have been characterized by single-crystal X-ray diffraction analyses, which reveal octahedral geometry for all three metal centers in 1-3. Compound 1 crystallizes in a monoclinic space group P2(1)/c, while both 2 and 3 have more symmetric structures with orthorhombic space group Pnma that renders the vanadium(V) centers in these compounds exactly identical. In DMF solution, compound 1 displays an 8-line EPR at room temperature with and values of 1.972 and 86.61 × 10(-4) cm(-1), respectively. High-resolution X-ray photoelectron spectrum (XPS) of this compound shows a couple of bands at 515.14 and 522.14 eV due to vanadium 2p(3/2) and 2p(1/2) electrons in the oxidation states +5 and +4, respectively. All of these, together with bond valence sum (BVS) calculation, confirm the trapped-valence nature of mixed-oxidation in compounds 1 and 2. Electrochemically, compound 1 undergoes two one-electron oxidations at E(1/2) = 0.52 and 0.83 V vs Ag/AgCl reference. While the former is due to a metal-based V(IV/V) oxidation, the latter one at higher potential is most likely due to a ligand-based process involving one of the catecholate centers. A larger cavity size in the upper compartment of the ligand H4L(3) is spacious enough to accommodate Re(V) with larger size to generate a rare type of all-oxido heterotrimetallic compound (3) as established by X-ray crystallography. PMID:23898782
A Class of New Metrics Based on Triangular Discrimination
Guoxiang Lu
2015-07-01
Full Text Available In the field of information theory, statistics and other application areas, the information-theoretic divergences are used widely. To meet the requirement of metric properties, we introduce a class of new metrics based on triangular discrimination which are bounded. Moreover, we obtain some sharp inequalities for the triangular discrimination and other information-theoretic divergences. Their asymptotic approximation properties are also involved.
Triangular nanobeam photonic cavities in single crystal diamond
Bayn, Igal; Meyler, Boris; Salzman, Joseph; Kalish, Rafi
2011-01-01
Diamond photonics provides an attractive architecture to explore room temperature cavity quantum electrodynamics and to realize scalable multi-qubit computing. Here we review the present state of diamond photonic technology. The design, fabrication and characterization of a novel triangular cross section nanobeam cavity produced in a single crystal diamond is demonstrated. The present cavity design, based on a triangular cross section allows vertical confinement and better signal collection e...
Approximating Runge-Kutta matrices by triangular matrices
Hoffmann, W.; Swart, de, P.
1997-01-01
The implementation of implicit Runge-Kutta methods requires the solution of large systems of non-linear equations. Normally these equations are solved by a modified Newton process, which can be very expensive for problems of high dimension. The recently proposed triangularly implicit iteration methods for ODE-IVP solvers [HSw95] substitute the Runge-Kutta matrix A in the Newton process for a triangular matrix T that approximates A, hereby making the method suitable for parallel implementation...
On the Eigenvalues and Eigenvectors of Block Triangular Preconditioned Block Matrices
Pestana, Jennifer
2014-01-01
Block lower triangular matrices and block upper triangular matrices are popular preconditioners for 2×2 block matrices. In this note we show that a block lower triangular preconditioner gives the same spectrum as a block upper triangular preconditioner and that the eigenvectors of the two preconditioned matrices are related. © 2014 Society for Industrial and Applied Mathematics.
Chemical compounds isolated from Talinum triangulare (Portulacaceae).
de Oliveira Amorim, Ana Paula; de Carvalho, Almir Ribeiro; Lopes, Norberto Peporine; Castro, Rosane Nora; de Oliveira, Marcia Cristina Campos; de Carvalho, Mário Geraldo
2014-10-01
This first phytochemical study of Talinum triangulare Leach (Portulacaceae), also known as 'cariru', which is a commonly consumed food in Northern Brazil, allowed the isolation and structural determination of four new compounds: one acrylamide, 3-N-(acryloyl, N-pentadecanoyl) propanoic acid (5), and three new phaeophytins named (15(1)S, 17R, 18R)-Ficuschlorin D acid (3(1),3(2)-didehydro-7-oxo-17(3)-O-phytyl-rhodochlorin-15-acetic acid), (13), Talichorin A (17R, 18R)-phaeophytin b-15(1)-hidroxy, 15(2),15(3)-acetyl-13(1)-carboxilic acid (14), and (15(1)S, 17R, 18R)-phaeophytin b peroxylactone or (15(1)S, 17R, 18R)-hydroperoxy-ficuschlorin D (16), together with twelve known compounds, including four phaeophytins (11,12, 15 and 17). The structures of the compounds were established on the basis of 1D and 2D NMR, IR, HRESI-MS spectra, including GC-MS, and HPLC-UV analysis, as well as comparisons with the literature data. The CD spectra data analysis were used to define the absolute configuration of phaeophytins 12 (13(2)R, 17R, 18R)-13(2)-hydroxyphaeophytin a, 13 and 16, 15 (15(1)S, 17R, 18R)-3(1),3(2)-didehydro-15(1)-hydroxyrhodochlorin-15-acetic acid δ-lactone-15(2)-methyl-17(3)-phytyl ester and 17 (17R, 18R)-purpurin 18-phytyl ester. PMID:24799228
Zhensong Chen; Shenghua Xiong; Yanlai Li; Kwai-Sang Chin
2015-01-01
In order to measure the uncertain information of a type-2 intuitionistic fuzzy set (T2IFS), an entropy measure of T2IFS is presented by using the constructive principles. The proposed entropy measure is also proved to satisfy al of the constructive principles. Further, a novel concept of the type-2 triangular in-tuitionistic trapezoidal fuzzy set (T2TITrFS) is developed, and a geometric interpretation of the T2TITrFS is given to comprehend it completely or correctly in a more intuitive way. To deal with a more general uncertain complex system, the constructive principles of an entropy measure of T2TITrFS are therefore proposed on the basis of the axiomatic definition of the type-2 intuitionisic fuzzy entropy measure. This paper elicits a formula of type-2 triangular intuitionistic trapezoidal fuzzy entropy and verifies that it does sa-tisfy the constructive principles. Two examples are given to show the efficiency of the proposed entropy of T2TITrFS in describing the uncertainty of the type-2 intuitionistic fuzzy information and il ustrate its application in type-2 triangular intuitionistic trapezodial fuzzy decision making problems.
Triangular Clinics: The Way of The Future
Seyed-Moayed Alavian
2005-09-01
other created the incentive to try something totally different. The Triangular Clinics, chosen the best practice forprevention and care for IDUs, started in Kermanshah in 2000, as a pilot study. The concept of the Triangular Clinic is to tackle three important issues: addressing IDUs through a harm reduction approach; the treatment of STDs; and care and support for People Living With HIV/AIDS (PLWHA. The problems of drug dependence, STDs and HIV are all behavioral in nature and hence the Clinic is a center for the treatment of behavioral diseases. By grouping the three together, it is possible to organize a comprehensive and integrated service to the patients(5. Such clinics deliver many services, integrating both prevention and care, as seen in figure 1. Services are provided by dedicated staff for drug abusers, people seeking voluntary HIV counseling and testing, PLWHA and their family members, high risk populations, patients with STDs and people exposed to potentially contaminated body fluids (Fig. 1. Harm reduction, as the core activity of Triangular Clinics, serves the infected ones well while other supportive services help healthy but at-risk population prevent the spread of HIV, HCV and other related ailments. We hope the already-in-place program of harm reduction gets national to cover all high risk populations including IDUs in and out of prison.
Statistical disordering of chalcogen atoms in cluster fragments of K4[Re6(μ3-S)8-y(μ3-Te)y(CN)6
X-ray diffraction investigation is conducted for three types of crystals of K4[Re6(μ3-S)8-y(μ3-Te)y(CN)6] - representatives of the continuous series of solid solutions prepared by high temperature reactions with the use of different initial substances. Syngony of the crystals is cubic, space group is Ia3. Statistical disordering of chalcogen atoms in cluster fragments [Re6(μ3-S)8-y(μ3-Te)y(CN)6] is investigated on data for three crystals. Results obtained show different effect of statistical disordering degree of Te and S on metric characteristics of the structures
Elliptic and triangular flow in asymmetric heavy-ion collisions
We present a study of the elliptic (v2) and triangular (v3) flow and their corresponding eccentricity fluctuations for asymmetric (Au+Ag, Au+Cu, and Au+Si) collisions at √(sNN) = 200 GeV. These are compared to the corresponding results from symmetric (Au+Au and Cu+Cu) collisions at the same energy. The study which is carried out using a multiphase transport (AMPT) model shows that triangularity (ε3), fluctuations in triangularity and v3 do not show much variation for the different colliding ion sizes studied. However the eccentricity (ε2), fluctuations in eccentricity and v2, shows a strong dependence on colliding ion size for a given number of participating nucleons. Our study thus indicates that asymmetric heavy-ion collisions could be used to constrain models dealing with flow fluctuations in heavy-ion collisions.
Field-design optimization with triangular heliostat pods
Domínguez-Bravo, Carmen-Ana; Bode, Sebastian-James; Heiming, Gregor; Richter, Pascal; Carrizosa, Emilio; Fernández-Cara, Enrique; Frank, Martin; Gauché, Paul
2016-05-01
In this paper the optimization of a heliostat field with triangular heliostat pods is addressed. The use of structures which allow the combination of several heliostats into a common pod system aims to reduce the high costs associated with the heliostat field and therefore reduces the Levelized Cost of Electricity value. A pattern-based algorithm and two pattern-free algorithms are adapted to handle the field layout problem with triangular heliostat pods. Under the Helio100 project in South Africa, a new small-scale Solar Power Tower plant has been recently constructed. The Helio100 plant has 20 triangular pods (each with 6 heliostats) whose positions follow a linear pattern. The obtained field layouts after optimization are compared against the reference field Helio100.
Elliptic and Triangular flow in asymmetric heavy-ion collisions
Haque, Md Rihan; Mohanty, Bedangadas
2011-01-01
We present a study of the elliptic (v2) and triangular (v3) flow and their corresponding eccentricity fluctuations for asymmetric (Au+Ag, Au+Cu and Au+Si) collisions at \\sqrt_NN = 200 GeV. These are compared to the corresponding results from symmetric (Au+Au and Cu+Cu) collisions at the same energy. The study which is carried out using a multi-phase transport (AMPT) model shows that triangularity (\\epsilon_3), fluctuations in triangularity and v3 do not show much variation for the different colliding ion sizes studied. However the eccentricity (\\epsilon_2), fluctuations in eccentricity and v2 shows a strong dependence on colliding ion size for a given number of participating nucleons. Our study thus indicates that asymmetric heavy-ion collisions could be used to constrain models dealing with flow fluctuations in heavy-ion collisions.
Universal triangular spectra in parametrically-driven systems
Akhmediev, Nail [Optical Sciences Group, Research School of Physics and Engineering, Institute of Advanced Studies, Australian National University, Canberra ACT 0200 (Australia); Ankiewicz, Adrian, E-mail: ana124@rsphysse.anu.edu.a [Optical Sciences Group, Research School of Physics and Engineering, Institute of Advanced Studies, Australian National University, Canberra ACT 0200 (Australia); Soto-Crespo, J.M. [Instituto de Optica, C.S.I.C., Serrano 121, 28006 Madrid (Spain); Dudley, John M. [Institut FEMTO-ST, UMR 6174 CNRS-Universite de Franche-Comte, 25030 Besancon (France)
2011-01-17
We analyse triangular spectra that appear in many branches of physics that deal with parametrically-driven systems, and give a simple theoretical analysis for them in terms of the nonlinear dynamics of multimode fields. Such spectra appear universally as a result of an exponential decay of the nonlinearly generated frequency modes of many parametrically-driven systems, and have been confirmed by recent observations of noise-driven supercontinuum generation in optical fibers. We demonstrate that such universal triangular spectra (UTS) can be well-described by the analytical expressions for the spectra of Akhmediev breather (AB) solutions at the point of maximal compression.
Hua, Guoxiong; Du, Junyi; Slawin, Alexandra M Z; Woollins, J Derek
2016-06-01
The development of new methodology for the preparation of functional macrocycles with practical applications is an important research area in macromolecular science. In this study, we report a new one-pot route for the synthesis of a series of macro-heterocycles by incorporating two phosphorus atoms and two chalcogen atoms and two oxygen atoms (double OP(S)SCn or OP(Se)SeCn scaffolds). The three-component condensation reactions of 2,4-diferrocenyl-1,3,2,4-diathiadiphosphetane 2,4-disulfide (FcLR, a ferrocene analogue of Lawesson's reagent) or 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide (LR, Lawesson's reagent), or 2,4-diphenyl-1,3,2,4-diselenadiphosphetane 2,4-diselenide (WR, Woollins' reagent), disodium alkenyl-diols, and dihalogenated alkanes are performed, giving rise to soluble and air or moisture-stable macrocycles in good-to-excellent yields (up to 92 %). This is the first systemically preparative and readily scalable example of one-pot ring opening/ring extending reaction of three-components to prepare phosphorus-chalcogen containing macrocycles. We also provide a systematic crystallographic study. PMID:27112964
Partitioning a chordal graph into transitive subgraphs for parallel sparse triangular solution
Peyton, B.W. [Oak Ridge National Lab., TN (United States); Pothen, A. [Waterloo Univ., ON (Canada). Dept. of Computer Science; Yuan, Xiaoqing [IBM Canada Lab., North York, Ontario (Canada)
1992-12-01
A recent approach for solving sparse triangular systems of equations on massively parallel computers employs a factorization of the triangular coefficient matrix to obtain a representation of its inverse in product form. The number of general communication steps required by this approach is proportional to the number of factors in the factorization. The triangular matrix can be symmetrically permuted to minimize the number of factors over suitable classes of permutations, and thereby the complexity of the parallel algorithm can be minimized. Algorithms for minimizing the number of factors over several classes of permutations have been considered in earlier work. Let F = L+L{sup T} denote the symmetric filled matrix corresponding to a Cholesky factor L, and let G{sub F} denote the adjacency graph of F. In this paper we consider the problem of minirriizing the number of factors over all permutations which preserve the structure of G{sub F}. The graph model of this problem is to partition the vertices G{sub F} into the fewest transitively closed subgraphs over all perfect elimination orderings while satisfying a certain precedence relationship. The solution to this chordal graph partitioning problem can be described by a greedy scheme which eliminates a largest permissible subgraph at each step. Further, the subgraph eliminated at each step can be characterized in terms of lengths of chordless paths in the current elimination graph. This solution relies on several results concerning transitive perfect elimination orderings introduced in this paper. We describe a partitioning algorithm with {Omicron}({vert_bar}V{vert_bar} + {vert_bar}E{vert_bar}) time and space complexity.
Partitioning a chordal graph into transitive subgraphs for parallel sparse triangular solution
Peyton, B.W. (Oak Ridge National Lab., TN (United States)); Pothen, A. (Waterloo Univ., ON (Canada). Dept. of Computer Science); Yuan, Xiaoqing (IBM Canada Lab., North York, Ontario (Canada))
1992-12-01
A recent approach for solving sparse triangular systems of equations on massively parallel computers employs a factorization of the triangular coefficient matrix to obtain a representation of its inverse in product form. The number of general communication steps required by this approach is proportional to the number of factors in the factorization. The triangular matrix can be symmetrically permuted to minimize the number of factors over suitable classes of permutations, and thereby the complexity of the parallel algorithm can be minimized. Algorithms for minimizing the number of factors over several classes of permutations have been considered in earlier work. Let F = L+L[sup T] denote the symmetric filled matrix corresponding to a Cholesky factor L, and let G[sub F] denote the adjacency graph of F. In this paper we consider the problem of minirriizing the number of factors over all permutations which preserve the structure of G[sub F]. The graph model of this problem is to partition the vertices G[sub F] into the fewest transitively closed subgraphs over all perfect elimination orderings while satisfying a certain precedence relationship. The solution to this chordal graph partitioning problem can be described by a greedy scheme which eliminates a largest permissible subgraph at each step. Further, the subgraph eliminated at each step can be characterized in terms of lengths of chordless paths in the current elimination graph. This solution relies on several results concerning transitive perfect elimination orderings introduced in this paper. We describe a partitioning algorithm with [Omicron]([vert bar]V[vert bar] + [vert bar]E[vert bar]) time and space complexity.
A Novel VOF-Type Volume-Tracking Method for Free-Surface Flows Based on Unstructured Triangular Mesh
JI Chun-ning; WANG Yuan-zhan; WANG Jian-feng
2005-01-01
A novel VOF-type volume-tracking method for two-dimensional free-surface flows based on the unstructured triangular mesh is presented. Owing to the inherent merit of the unstructured triangular mesh in fitting curved boundaries, this method can handle the free-surface problems with complex geometries accurately and directly, without introducing any complicated boundary treatment or artificial diffusion. The method solves the volume transport equation geometrically through the Modified Lagrangian-Eulerian Re-map (MLER) method, which is applied to advective fluid volumes. Moreover, the PLIC method is adopted to give a second-order reconstructed interface approximation. To validate this method, two advection tests were performed for the establishment of the accuracy and convergence rate of the solutions. Numerical results for these complex tests provide convincing evidence for the excellent solution quality and fidelity of the method.
Anisotropic Adhesion Properties of Triangular-Tip-Shaped Micropillars
Kwak, Moon Kyu
2011-06-01
Directional dry adhesive microstructures consisting of high-density triangular-tip-shaped micropillars are described. The wide-tip structures allow for unique directional shear adhesion properties with respect to the peeling direction, along with relatively high normal adhesion. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Selectively colorimetric detection of cysteine with triangular silver nanoprisms
Tong Wu; Yuan Fang Li; Cheng Zhi Huang
2009-01-01
Triangular silver nanoprisms were prepared and applied to make colorimetric detection of cysteine based on our findings that cysteine could lead to the blue shift of the dipole plasmon resonance absorption,but other 19 kinds of natural amino acids could not.Cysteine with a concentration 160 nmol/L can result in a color change that can be discerned with naked eyes.
A Subdivision Scheme for Rational Triangular Bezier Surfaces
胡事民
1996-01-01
An explicit formula is developed to decompose a rational triangular Bezier patch into three non-degenerate rational rectangular Bezier patches of the same degree.This formula yields a stable algorithm to compute the control vertices of those three rectangular subpatches.Some properties of the subdivision are discussed and the formula is illustrated with an example.
The Numerical Integration of Discrete Functions on a Triangular Element
无
2001-01-01
With the application of Hammer integral formulas of a continuousfunction on a triangular element, the numerical integral formulas of some discrete functions on the element are derived by means of decomposition and recombination of base functions. Hammer integral formulas are the special examples of those of the paper.
Aranha: a 2D mesh generator for triangular finite elements
A method for generating unstructured meshes for linear and quadratic triangular finite elements is described in this paper. Some topics on the C language data structure used in the development of the program Aranha are also presented. The applicability for adaptive remeshing is shown and finally several examples are included to illustrate the performance of the method in irregular connected planar domains. (author)
On certain diophantine equations related to triangular and tetrahedral numbers
Ulas, Maciej
2008-01-01
In this paper we give solutions of certain diophantine equations related to triangular and tetrahedral numbers and propose several problems connected with these numbers. The material of this paper was presented in part at the 11th International Workshop for Young Mathematicians - NUMBER THEORY, Krak\\'{o}w, 14th-20th september 2008.
Coxeter Decompositions of Bounded Hyperbolic Pyramids and Triangular Prisms
Felikson, A.
2002-01-01
Coxeter decompositions of hyperbolic simplices where studied in math.MG/0212010 and math.MG/0210067. In this paper we use the methods of these works to classify Coxeter decompositions of bounded convex pyramids and triangular prisms in the hyperbolic space H^3.
Photonic Crystal Waveguides in Triangular Lattice of Nanopillars
Chigrin, Dmitry N.; Lavrinenko, Andrei
Photonic nanopillars waveguides have been analysed. Dielectric nanopillars are arranged in such way that they from a tringular lattice of 2D photonic crystal. Dispersion of the modes depends on the direction of the triangular lattice, Ã-J or Ã-X, in which nanopillars arrays are extended. Light...
Oliveira Amorim, Ana Paula; Campos de Oliveira, Márcia Cristina; de Azevedo Amorim, Thiago; Echevarria, Aurea
2013-01-01
The aim of this work is to evaluate the antioxidant activity against the radical species DPPH, the reducing capacity against Fe II ions, and the inhibitory activity on the tyrosinase enzyme of the T. triangulare. Hydromethanolic crude extract provided two fractions after the liquid/liquid partition with chloroform. The Folin-Ciocalteu method determined the total phenolic content of the crude extract (CE) and the hydromethanolic fraction (Fraction 1), resulting in a concentration of 0.5853 g/100 g for Fraction 1, and 0.1400 g/100 g for the CE. Taking into account the results of the DPPH, the free radical scavenging capacity was confirmed. The formation of complexes with Fe II ions was evaluated by UV/visible spectrometry; results showed that CE has complexing power similar to the positive control (Gingko biloba extract).The inhibitory capacity of samples against the tyrosinase enzyme was determined by the oxidation of L-DOPA, providing IC50 values of 13.3 μg·mL−1 (CE) and 6.6 μg·mL−1 (Fraction 1). The values indicate that Fraction 1 was more active and showed a higher inhibitory power on the tyrosinase enzyme than the ascorbic acid, used as positive control. The hydromethanolic extract of T. triangulare proved to have powerful antioxidant activity and to inhibit the tyrosinase enzyme; its potential is increased after the partition with chloroform. PMID:26784338
Ana Paula Oliveira Amorim
2013-07-01
Full Text Available The aim of this work is to evaluate the antioxidant activity against the radical species DPPH, the reducing capacity against Fe II ions, and the inhibitory activity on the tyrosinase enzyme of the T. triangulare. Hydromethanolic crude extract provided two fractions after the liquid/liquid partition with chloroform. The Folin-Ciocalteu method determined the total phenolic content of the crude extract (CE and the hydromethanolic fraction (Fraction 1, resulting in a concentration of 0.5853 g/100 g for Fraction 1, and 0.1400 g/100 g for the CE. Taking into account the results of the DPPH, the free radical scavenging capacity was confirmed. The formation of complexes with Fe II ions was evaluated by UV/visible spectrometry; results showed that CE has complexing power similar to the positive control (Gingko biloba extract.The inhibitory capacity of samples against the tyrosinase enzyme was determined by the oxidation of L-DOPA, providing IC50 values of 13.3 μg·mL−1 (CE and 6.6 μg·mL−1 (Fraction 1. The values indicate that Fraction 1 was more active and showed a higher inhibitory power on the tyrosinase enzyme than the ascorbic acid, used as positive control. The hydromethanolic extract of T. triangulare proved to have powerful antioxidant activity and to inhibit the tyrosinase enzyme; its potential is increased after the partition with chloroform.
Oliveira Amorim, Ana Paula; Campos de Oliveira, Márcia Cristina; de Azevedo Amorim, Thiago; Echevarria, Aurea
2013-01-01
The aim of this work is to evaluate the antioxidant activity against the radical species DPPH, the reducing capacity against Fe II ions, and the inhibitory activity on the tyrosinase enzyme of the T. triangulare. Hydromethanolic crude extract provided two fractions after the liquid/liquid partition with chloroform. The Folin-Ciocalteu method determined the total phenolic content of the crude extract (CE) and the hydromethanolic fraction (Fraction 1), resulting in a concentration of 0.5853 g/100 g for Fraction 1, and 0.1400 g/100 g for the CE. Taking into account the results of the DPPH, the free radical scavenging capacity was confirmed. The formation of complexes with Fe II ions was evaluated by UV/visible spectrometry; results showed that CE has complexing power similar to the positive control (Gingko biloba extract).The inhibitory capacity of samples against the tyrosinase enzyme was determined by the oxidation of L-DOPA, providing IC50 values of 13.3 μg·mL(-1) (CE) and 6.6 μg·mL(-1) (Fraction 1). The values indicate that Fraction 1 was more active and showed a higher inhibitory power on the tyrosinase enzyme than the ascorbic acid, used as positive control. The hydromethanolic extract of T. triangulare proved to have powerful antioxidant activity and to inhibit the tyrosinase enzyme; its potential is increased after the partition with chloroform. PMID:26784338
Hollow Ag/Pd triangular nanoplate: a novel activator for electroless nickel deposition
Hollow Ag/Pd triangular nanoplates have been successfully prepared by a galvanic displacement reaction, in which added Pd2+ ions react with Ag triangular nanoplates as templates. By altering the sizes of the Ag nanotemplates, Ag/Pd triangular nanoplates of different sizes can be prepared. Additionally, the large alloy nanoplates show maximum electrochemical activity when Ag/Pd triangular nanoplates of different sizes are applied as new activators for electroless nickel deposition
The formation of ammonium cobalt (II) phosphate was utilized to synthesize unprecedented 3D structures of Co3O4, triangular prisms and trunk-like structures, via a self-supported and organics-free method. The length of a triangular side of the prepared 3D triangular prisms is ~1...
郑鑫; 解学关; 王安远; 张义鹏; 高伟阳; 蒋良福; 陈星隆; 张国佑; 丁健; 周飞亚; 宋永焕; 李晓阳
2011-01-01
目的 对腕关节三角纤维软骨复合体(TFCC)损伤行关节镜检查,并分析其疗效.方法 对2006年1月至2009年12月诊断为TFCC损伤并行腕关节镜治疗的15例患者进行回顾性分析,其中男6例、女9例,平均年龄42岁,平均随访时间26.5个月.根据Palmer分型,Ⅰ型损伤5例(ⅠA型3例,ⅠB型1例,ⅠD型1例),Ⅱ型损伤10例(ⅡA型6例,ⅡC型4例).所有患者保守治疗3个月以上无效后行关节镜治疗.测量指标:腕关节疼痛、握力、关节活动度、腕关节评分(改良Mayo评分)、DASH问卷.结果 术后15例患者腕关节疼痛均有缓解,握力改善;腕关节屈伸(129±26)°,桡尺偏(40±8)°,旋转(174±11)°.按照改良Mayo评分:优3例,良8例,可4例;优良率为73%.术后DASH评分为4～28分,平均(15±7)分.结论 关节镜对于TFCC损伤的诊断明显优于MRI检查,而且关节镜能在检查的同时进行治疗,应作为腕尺痛的常规诊断手段.关节镜治疗各型TFCC损伤均能缓解疼痛,但Ⅰ型效果好于Ⅱ型.伴有尺骨正变异的TFCC损伤应同时行尺骨缩短术以提高术后效果.%Objective The objective of this study was to determine the efficiency of arthroscopic diagnosis and repair of triangular fibrocartilage complex (TFCC) tears. Methods Fifteen cases of TFCC tears diagnosed and treated with arthroscopic repair in our hospital between January 2006 and December 2009 were retrospectively reviewed. There were six males and nine females. The average age was 42 years. The average follow-up was 26.5 months. TFCC tears were classified by Palmer classification as follows:ⅠA (3 cases),ⅠB (1 case),ⅠD (1 case),ⅡA (6 cases),and ⅡC (4 cases). Arthroscopic repair was performed after at least 3 months of conservative treatment failed. Wrist pain,grip strength,range of motion (ROM),wrist score (modified Mayo wrist score),disabilities of the arm,shoulder,and hand questionnaire (DASH) score were evaluated. Results Postoperatively alleviation of
On the Construction of Jointly Superregular Lower Triangular Toeplitz Matrices
Hansen, Jonas; Østergaard, Jan; Kudahl, Johnny;
2016-01-01
Superregular matrices have the property that all of their submatrices, which can be full rank are so. Lower triangular superregular matrices are useful for e.g., maximum distance separable convolutional codes as well as for (sequential) network codes. In this work, we provide an explicit design...... for all superregular lower triangular Toeplitz matrices in GF(2p) for the case of matrices with dimensions less than or equal to 5 × 5. For higher dimensional matrices, we present a greedy algorithm that find a solution provided the field size is sufficiently high. We also introduce the notions of jointly...... superregular and product preserving jointly superregular matrices, and extend our explicit constructions of superregular matrices to these cases. Jointly superregular matrices are necessary to achieve optimal decoding capabilities for the case of codes with a rate lower than 1/2, and the product preserving...
(2-1)-Ideal amenability of triangular banach algebras
S Etemad; M Ettefagh
2015-05-01
Let $\\mathcal{A}$ and $\\mathcal{B}$ be two unital Banach algebras and let $\\mathcal{M}$ be an unital Banach $\\mathcal{A}$, $\\mathcal{B}$-module. Also, let $\\mathcal{T}=\\left[\\begin{smallmatrix} \\mathcal{A} & \\mathcal{M}\\\\ & \\mathcal{B}\\end{smallmatrix}\\right]$ be the corresponding triangular Banach algebra. Forrest and Marcoux (Trans. Amer. Math. Soc. 354 (2002) 1435–1452) have studied the -weak amenability of triangular Banach algebras. In this paper, we investigate (2-1)-ideal amenability of $\\mathcal{T}$ for all ≥ 1. We introduce the structure of ideals of these Banach algebras and then, we show that (2-1)-ideal amenability of $\\mathcal{T}$ depends on (2-1)-ideal amenability of Banach algebras $\\mathcal{A}$ and $\\mathcal{B}$.
A Novel Triangular Shaped UWB Fractal Antenna Using Circular Slot
Shahu, Babu Lal; Pal, Srikanta; Chattoraj, Neela
2016-03-01
The article presents the design of triangular shaped fractal based antenna with circular slot for ultra wideband (UWB) application. The antenna is fed using microstrip line and has overall dimension of 24×24×1.6 mm3. The proposed antenna is covering the wide frequency bandwidth of 2.99-11.16 GHz and is achieved using simple fractal based triangular-circular geometries and asymmetrical ground plane. The antenna is designed and parametrical studies are performed using method of moment (MOM) based Full Wave Electromagnetic (EM) software Simulator Zeland IE3D. The prototype of proposed antenna is fabricated and tested to compare the simulated and measured results of various antenna parameters. The antenna has good impedance bandwidth, nearly constant gain and stable radiation pattern. Measured return loss shows fair agreement with simulated one. Also measured group delay variation obtained is less than 1.0 ns, which proves good time domain behavior of the proposed antenna.
Block-triangular preconditioners for PDE-constrained optimization
Rees, Tyrone
2010-11-26
In this paper we investigate the possibility of using a block-triangular preconditioner for saddle point problems arising in PDE-constrained optimization. In particular, we focus on a conjugate gradient-type method introduced by Bramble and Pasciak that uses self-adjointness of the preconditioned system in a non-standard inner product. We show when the Chebyshev semi-iteration is used as a preconditioner for the relevant matrix blocks involving the finite element mass matrix that the main drawback of the Bramble-Pasciak method-the appropriate scaling of the preconditioners-is easily overcome. We present an eigenvalue analysis for the block-triangular preconditioners that gives convergence bounds in the non-standard inner product and illustrates their competitiveness on a number of computed examples. Copyright © 2010 John Wiley & Sons, Ltd.
Kernel methods and scale invariance using the triangular kernel
Sahbi, Hichem; Fleuret, François
2004-01-01
We focus in this paper on the scale invariance of kernel methods using a particular function referred to as the triangular kernel. The study in (Sahbi and Fleuret, 2002) reported scale invariance for support vector machines (SVM) and the current work is an extension for support vector regression (SVR) and kernel principal component analysis (KPCA). First, we review these kernel methods and we illustrate analytically the scale invariance of the training processes. Experiments are conducted in ...
A novel optical multilayer hydrophone with a triangular pyramid substrate
Suyong Wu; Xingwu Long; Kaiyong Yang; Yun Huang
2011-01-01
@@ A novel concept for an optical multilayer ultrasonic hydrophone with the sensing film deposited on a triangular pyramid glass substrate is proposed. Using the calculation model for the spectral coefficients' derivatives of a dielectric multilayer optical coating, the acousto-optic sensitivity characteristic of the hydrophone is analyzed with different measurement laser polarizations and incident angles. We present a reasonable method and adjusting strategy for the optimum working point selection of the ultrasound measurement. Analytic results show that the novel hydrophone possesses all the other merits of a plate glass substrate optical multilayer hydrophone but with improved detection sensitivity. A longer measurement time without distortion decreases the difficulty of high frequency signal circuits. Spatial split of the ultrasound signal caused by the substrate's triangular pyramid roof simplifies the spatial spot area correction,which contributes to the accurate calibration of the hydrophone's wideband frequency response.%A novel concept for an optical multilayer ultrasonic hydrophone with the sensing film deposited on a triangular pyramid glass substrate is proposed. Using the calculation model for the spectral coefficients'derivatives of a dielectric multilayer optical coating, the acousto-optic sensitivity characteristic of the hydrophone is analyzed with different measurement laser polarizations and incident angles. We present a reasonable method and adjusting strategy for the optimum working point selection of the ultrasound measurement. Analytic results show that the novel hydrophone possesses all the other merits of a plate glass substrate optical multilayer hydrophone but with improved detection sensitivity. A longer measurement time without distortion decreases the difficulty of high frequency signal circuits. Spatial split of the ultrasound signal caused by the substrate's triangular pyramid roof simplifies the spatial spot area correction
Mott Insulating Ground State on a Triangular Surface Lattice
Momentum-resolved direct and inverse photoemission spectra of the K/Si(111)-(√(3)x√(3))R30 degree-B interface reveals the presence of strongly localized surface states. The K overlayer remains nonmetallic up to the saturation coverage. This system most likely presents the first experimental realization of a frustrated spin 1/2 Heisenberg antiferromagnet on a two-dimensional triangular lattice. copyright 1997 The American Physical Society
NEW SECOND ORDER NONCONFORMING TRIANGULAR ELEMENT FOR PLANAR ELASTICITY PROBLEMS
Chen Shaochun; Zheng Yanjun; Mao Shipeng
2011-01-01
In the use of finite element methods to the planar elasticity problems, one difficulty is to overcome locking when elasticity constant λ→∞. In the case of traction boundary condition, another difficulty is to make the discrete Korn's second inequality valid. In this paper, a triangular element is presented. We prove that this element is locking-free, the discrete Korn's second inequality holds and the convergence order is two.
Maxima of Dirichlet and triangular arrays of gamma variables
Bose, Arup; Dasgupta, Amites; Maulik, Krishanu
2008-01-01
Consider a rowwise independent triangular array of gamma random variables with varying parameters. Under several different conditions on the shape parameter, we show that the sequence of row-maximums converges weakly after linear or power transformation. Depending on the parameter combinations, we obtain both Gumbel and non-Gumbel limits. The weak limits for maximum of the coordinates of certain Dirichlet vectors of increasing dimension are also obtained using the gamma representation.
Natural convection in asymmetric triangular enclosures heated from below
Triangular enclosures are typical configurations of attic spaces found in residential as well as industrial pitched-roof buildings. Natural convection in triangular rooftops has received considerable attention over the years, mainly on right-angled and isosceles enclosures. In this paper, a finite volume CFD package is employed to study the laminar air flow and temperature distribution in asymmetric rooftop-shaped triangular enclosures when heated isothermally from the base wall, for aspect ratios (AR) 0.2 ≤ AR ≤ 1.0, and Rayleigh number (Ra) values 8 × 105 ≤ Ra ≤ 5 × 107. The effects of Rayleigh number and pitch angle on the flow structure and temperature distributions within the enclosure are analysed. Results indicate that, at low pitch angle, the heat transfer between the cold inclined and the hot base walls is very high, resulting in a multi-cellular flow structure. As the pitch angle increases, however, the number of cells reduces, and the total heat transfer rate progressively reduces, even if the Rayleigh number, being based on the enclosure height, rapidly increases. Physical reasons for the above effect are inspected
Effective Lateral Canthal Lengthening with Triangular Rotation Flap
2016-01-01
In Korea, lateral canthoplasty, along with medial epicanthoplasty, has become popular over the past years to widen the horizontal length of the palpebral fissure. However, the effect of the surgery differs greatly depending on the shape and structure of the eyes. If over-widened, complications such as eversion, scarring, and conjunctival exposure may occur. Thus, the author of this study suggests a more effective and safe method for lateral canthal lengthening that causes minimal complications. A total of 236 patients underwent lateral canthoplasty between July 2007 and December 2015. For each patient, a triangular flap 4–5 mm away from the lateral canthus was elevated and rotated 45 degrees laterally while the continuity of the lower eyelid gray line was maintained. A new lateral canthus was created by fixating the rotation flap to the lateral orbital rim with minimal skin trimming and tension-free sutures, preventing relapse and maintaining a triangular shape. In more than 95% of cases, effective and satisfactory extension was achieved. On average, a 3 mm extension of the lateral canthus was achieved. There were minor complications such as wound dehiscence, webbing, and scarring, which were easily corrected. The author not only extended the lateral canthus 3–4 mm laterally but also maintained the continuity of the gray line on the lower lid as a more natural-looking triangular shape, while minimizing complications such as webbing and conjunctival exposure.
Magnetic properties of a spin-1 triangular Ising system
We studied some magnetic behaviors of the Blume-Capel (BC) model in a site diluted triangular lattice by means of the effective-field theory (EFT) with correlations. The effects of the exchange interaction (J), crystal field (D), concentration (p) and temperature (T) on the magnetic properties of the spin-1 BC model in a triangular lattice, such as magnetization, susceptibility, phase diagram and hysteresis behaviors, are investigated in detail. The phase diagrams of the system are presented in two different planes. The tricritical point as well as the tetracritical and critical end special points are found to depend on the physical parameters of the system. Moreover, when the hysteresis behaviors of the system are examined, single and double hysteresis loops are observed for various values of the physical parameters. We show that the hysteresis loops have different coercive field points in which the susceptibility makes a peak at these points. - Highlights: • The triangular Ising system is investigated within EFT with correlations. • The effects of the interaction parameters on spin-1 BC model are studied. • The phase diagrams are found for the different interaction parameters. • The hysteresis behaviors of the system are examined. • The system shows the tricritical, tetracritical and critical end special points
Magnetic properties of a spin-1 triangular Ising system
Ertaş, Mehmet [Department of Physics, Erciyes University, 38039 Kayseri (Turkey); Kocakaplan, Yusuf [Graduate School of Natural and Applied Sciences, Erciyes University, 38039 Kayseri (Turkey); Kantar, Ersin, E-mail: ersinkantar@erciyes.edu.tr [Department of Physics, Erciyes University, 38039 Kayseri (Turkey)
2015-07-15
We studied some magnetic behaviors of the Blume-Capel (BC) model in a site diluted triangular lattice by means of the effective-field theory (EFT) with correlations. The effects of the exchange interaction (J), crystal field (D), concentration (p) and temperature (T) on the magnetic properties of the spin-1 BC model in a triangular lattice, such as magnetization, susceptibility, phase diagram and hysteresis behaviors, are investigated in detail. The phase diagrams of the system are presented in two different planes. The tricritical point as well as the tetracritical and critical end special points are found to depend on the physical parameters of the system. Moreover, when the hysteresis behaviors of the system are examined, single and double hysteresis loops are observed for various values of the physical parameters. We show that the hysteresis loops have different coercive field points in which the susceptibility makes a peak at these points. - Highlights: • The triangular Ising system is investigated within EFT with correlations. • The effects of the interaction parameters on spin-1 BC model are studied. • The phase diagrams are found for the different interaction parameters. • The hysteresis behaviors of the system are examined. • The system shows the tricritical, tetracritical and critical end special points.
Development of Negative Triangularity Plasmas in DIII-D
Walker, M. L.
2015-11-01
We report on development of DIII-D electron cyclotron heated discharges with controlled negative triangularity plasma shapes, to evaluate the effect on electron heat transport in L-mode plasmas, as reported on TCV. Analysis of TCV data found that negative triangularity exerts a stabilizing influence on the trapped electron mode, the dominant instability in the conditions of those experiments. Major objectives of the DIII-D development are producing complementary plasmas, one with negative and one with positive triangularity, approximately symmetric in major radial coordinate and having similar density and current profiles. Major constraints include selection of plasma parameters and toroidal field to optimize fluctuation diagnostic measurements while preventing transition from L- to H-mode and deposition of EC heating power near the q=1 surface to limit sawteeth. Issues discussed are definition of control scenarios by which the pair of shapes are accessed and their resulting controllability under the constraints imposed by DIII-D shaping control. Supported by US DOE under DE-FC02-04ER54698.
Gershenson, Carlos
2011-01-01
The term complexity derives etymologically from the Latin plexus, which means interwoven. Intuitively, this implies that something complex is composed by elements that are difficult to separate. This difficulty arises from the relevant interactions that take place between components. This lack of separability is at odds with the classical scientific method - which has been used since the times of Galileo, Newton, Descartes, and Laplace - and has also influenced philosophy and engineering. In recent decades, the scientific study of complexity and complex systems has proposed a paradigm shift in science and philosophy, proposing novel methods that take into account relevant interactions.
TRESS, Triangular Mesh Stress and Strain in R-Z, X-Y Geometry for Various Load and Temperature
1 - Nature of physical problem solved: The program considers the problem of evaluating stresses and strains in two dimensions, given various loading and temperature conditions. Provision is made for 'fixed displacements' and 'lines of symmetry'. R-z and x-y geometries are available, and in the latter the program is able to do either a plane stress or a plane strain calculation. Also available is an option enabling the user to specify only the boundary of the body; the program will then design its own triangular element mesh. Various graphical output options are available. 2 - Method of solution: The program uses triangular finite elements. A set of simultaneous equations (stiffness matrix) is set up connecting the total loads at nodal points with the displacements of these points. These equations are solved using the routine SPARSE, in such a way that additional loading cases may be done with negligible extra running time. Irregular triangular elements may be used, allowing great flexibility in the representation of irregular bodies. Arbitrary variation of material parameters is achieved by covering the body with a set of circles, triangles, or squares, within each of which material parameters are prescribed. Material properties may vary with temperature. 3 - Restrictions on the complexity of the problem: About 1000 nodes. Not more than 500 fixed displacements and 500 'line of symmetry'
This study investigates the effects of computed tomography (CT) parameters on the quality and size of the reverse triangular surface model with an objective of obtaining an accurate 3D triangular surface model of complex-shaped customized objects for reverse engineering and many other applications such as surgical planning and finite element analysis. For this purpose, the fibula of a human knee joint was CT scanned by changing various parameters (slice thickness, slice spacing, pixel size, X-ray tube current and helical pitch) over wide ranges. Three-dimensional triangular surface models were created from point cloud data extracted from the CT image data. To assess the influences of scanning parameters on the surface quality and accuracy, the resulting surface models were qualitatively compared based on various anatomical features. Statistical analysis was used to quantify the deviations of surface models with different scanning parameter levels from the reference CT surface model. The results show that these parameters to a varying degree affect the surface quality, reproduction of various anatomical details and size of the resulting surface model. Moreover, these parameters are highly dependent on each other. Interactive effects of these parameters have been discussed and recommendations have been made for parameter settings. The results of the study would help to improve the accuracy of the 3D surface models required for customized implants and other applications. (author)
Hayat, Nasir; Ahmad, Mushtaq, E-mail: nasirhayat@uet.edu.pk [Faculty of Mechanical Engineering, UET, Lahore (Pakistan)
2016-01-15
This study investigates the effects of computed tomography (CT) parameters on the quality and size of the reverse triangular surface model with an objective of obtaining an accurate 3D triangular surface model of complex-shaped customized objects for reverse engineering and many other applications such as surgical planning and finite element analysis. For this purpose, the fibula of a human knee joint was CT scanned by changing various parameters (slice thickness, slice spacing, pixel size, X-ray tube current and helical pitch) over wide ranges. Three-dimensional triangular surface models were created from point cloud data extracted from the CT image data. To assess the influences of scanning parameters on the surface quality and accuracy, the resulting surface models were qualitatively compared based on various anatomical features. Statistical analysis was used to quantify the deviations of surface models with different scanning parameter levels from the reference CT surface model. The results show that these parameters to a varying degree affect the surface quality, reproduction of various anatomical details and size of the resulting surface model. Moreover, these parameters are highly dependent on each other. Interactive effects of these parameters have been discussed and recommendations have been made for parameter settings. The results of the study would help to improve the accuracy of the 3D surface models required for customized implants and other applications. (author)
Yanbing Ju
2014-01-01
Full Text Available This paper studies the multiattribute decision making (MADM problems in which the attribute values take the form of dual hesitant fuzzy triangular linguistic elements and the weights of attributes take the form of real numbers. Firstly, to solve the situation where the membership degree and the nonmembership degree of an element to a triangular linguistic variable, the concept, operational laws, score function, and accuracy function of dual hesitant fuzzy triangular linguistic elements (DHFTLEs are defined. Then, some dual hesitant fuzzy triangular linguistic geometric aggregation operators are developed for aggregating the DHFTLEs, including dual hesitant fuzzy triangular linguistic weighted geometric (DHFTLWG operator, dual hesitant fuzzy triangular linguistic ordered weighted geometric (DHFTLOWG operator, dual hesitant fuzzy triangular linguistic hybrid geometric (DHFTLHG operator, generalized dual hesitant fuzzy triangular linguistic weighted geometric (GDHFTLWG operator, and generalized dual hesitant fuzzy triangular linguistic ordered weighted geometric (GDHFTLOWG operator. Furthermore, some desirable properties of these operators are investigated in detail. Based on the proposed operators, an approach to MADM with dual hesitant fuzzy triangular linguistic information is proposed. Finally, a numerical example for investment alternative selection is given to illustrate the application of the proposed method.
Dung Y. Liao; Yu C. Chai; Sue H. Wang; Chih W. Chen; Ming S. Tsai
2015-01-01
In this study, leaves and stems of Talinum triangulare were sequentially extracted with phosphate buffer solution to obtain PTL and PTS (phosphate buffered extracts of T. triangulare leaves and stems), with 75% ethanol to obtained ETL and ETS (ethanol extracts of T. triangulare leaves and stems), or with 90°C boiling water to obtain WTL and WTS (water extracts of T. triangulare leaves and stems). We investigated the antioxidant activities of various T. triangulare extracts, analyzed the extra...
Sutthisak Phongthanapanich; Pramote Dechaumphai
2011-01-01
Level set methods are widely used for predicting evolutions of complex free surface topologies,such as the crystal and crack growth,bubbles and droplets deformation,spilling and breaking waves,and two-phase flow phenomena.This paper presents a characteristic level set equation which is derived from the two-dimensional level set equation by using the characteristic-based scheme.An explicit finite volume element method is developed to discretize the equation on triangular grids.Several examples are presented to demonstrate the performance of the proposed method for calculating interface evolutions in time.The proposed level set method is also coupled with the Navier-Stokes equations for two-phase immiscible incompressible flow analysis with surface tension.The Rayleigh-Taylor instability problem is used to test and evaluate the effectiveness of the proposed scheme.
Improved triangular prism methods for fractal analysis of remotely sensed images
Zhou, Yu; Fung, Tung; Leung, Yee
2016-05-01
Feature extraction has been a major area of research in remote sensing, and fractal feature is a natural characterization of complex objects across scales. Extending on the modified triangular prism (MTP) method, we systematically discuss three factors closely related to the estimation of fractal dimensions of remotely sensed images. They are namely the (F1) number of steps, (F2) step size, and (F3) estimation accuracy of the facets' areas of the triangular prisms. Differing from the existing improved algorithms that separately consider these factors, we simultaneously take all factors to construct three new algorithms, namely the modification of the eight-pixel algorithm, the four corner and the moving-average MTP. Numerical experiments based on 4000 generated images show their superior performances over existing algorithms: our algorithms not only overcome the limitation of image size suffered by existing algorithms but also obtain similar average fractal dimension with smaller standard deviation, only 50% for images with high fractal dimensions. In the case of real-life application, our algorithms more likely obtain fractal dimensions within the theoretical range. Thus, the fractal nature uncovered by our algorithms is more reasonable in quantifying the complexity of remotely sensed images. Despite the similar performance of these three new algorithms, the moving-average MTP can mitigate the sensitivity of the MTP to noise and extreme values. Based on the numerical and real-life case study, we check the effect of the three factors, (F1)-(F3), and demonstrate that these three factors can be simultaneously considered for improving the performance of the MTP method.
Triangular preconditioners for saddle point problems with a penalty term
Klawonn, A. [Westfaelische Wilhelms-Universitaet, Muenster (Germany)
1996-12-31
Triangular preconditioners for a class of saddle point problems with a penalty term are considered. An important example is the mixed formulation of the pure displacement problem in linear elasticity. It is shown that the spectrum of the preconditioned system is contained in a real, positive interval, and that the interval bounds can be made independent of the discretization and penalty parameters. This fact is used to construct bounds of the convergence rate of the GMRES method used with an energy norm. Numerical results are given for GMRES and BI-CGSTAB.
The Hill-determinant perturbation theory with triangular propagators
A new version of the Rayleigh-Schroedinger perturbation prescription is proposed. Its main formal feature lies in an unusual choice of the model space and unperturbed H0 and in a resulting lower-triangular matrix structure of its propagators. Within the framework of the so-called Hill-determinant method, an admissibility of any incompletely solvable zero-order Hamiltonian is achieved in this way. As a consequence, the range of practical applicability of our new perturbative formalism may be expected to incorporate many new phenomenological interactions with a strongly anharmonic character. 18 refs
STL Triangular Mesh Generation Based on SAT Model
Yuwei Zhang
2013-06-01
Full Text Available Mesh generation is a fundamental technique in multiple domains. In this study, a STL triangular mesh generation method based on SAT model is proposed. Two novel triangulation methods, the constrained Delaunay algorithm and the grid subtraction algorithm, are employed on the multi-loop planer regions and the curved surfaces respectively. For the use of node adjustment, the mesh nodes on the surface boundary are strictly matched, with no cracks created on the joint of model surfaces. Experiments show that the proposed solution works effectively and high quality of the mesh model is achieved.
A Short Polarization Converter Using a Triangular Waveguide
Yamauchi, Junji; Yamanoue, Masahiro; Nakano, Hisamatsu
2008-01-01
A novel polarization converter using a triangular waveguide is proposed and analyzed by the imaginary-distance beam-propagation method based on Yee's mesh and the finite-difference time-domain method. The polarization conversion length is investigated as a function of relative refractive index difference. It is found, for a silicon core embedded in a silica cladding, that the conversion length is 2 mum, while the insertion loss is 0.5 dB at a wavelength of 1.55 mum. The extinction ratio is mo...
Self-avoiding walks and polygons on the triangular lattice
Jensen, Iwan
2004-01-01
We use new algorithms, based on the finite lattice method of series expansion, to extend the enumeration of self-avoiding walks and polygons on the triangular lattice to length 40 and 60, respectively. For self-avoiding walks to length 40 we also calculate series for the metric properties of mean-square end-to-end distance, mean-square radius of gyration and the mean-square distance of a monomer from the end points. For self-avoiding polygons to length 58 we calculate series for the mean-squa...
Triangular Dynamic Architecture for Distributed Computing in a LAN Environment
Hossain, M Shahriar; Fuad, M Muztaba; Deb, Debzani
2011-01-01
A computationally intensive large job, granulized to concurrent pieces and operating in a dynamic environment should reduce the total processing time. However, distributing jobs across a networked environment is a tedious and difficult task. Job distribution in a Local Area Network based on Triangular Dynamic Architecture (TDA) is a mechanism that establishes a dynamic environment for job distribution, load balancing and distributed processing with minimum interaction from the user. This paper introduces TDA and discusses its architecture and shows the benefits gained by utilizing such architecture in a distributed computing environment.
THE EFFECT OF AN ELASTIC TRIANGULAR INCLUSION ON A CRACK
焦贵德; 王银邦
2003-01-01
The interaction between an elastic triangular inclusion and a crack is investigated. The problem is formulated using the boundary integral equations for traction boundary value problems derived by Chau and Wang as basic equations. By using the continuity condition of traction and displacement on interface as supplement equations, a set of equations for solving the interaction problem between an inclusion and a crack are obtained, which are solved by asing a new boundary element method. The results in terms of stress intensity factors (SIFs) are calculated for a variety of crack-inclusion arrangements and the elastic constants of the matrix and the inclusion. The results are valuable for studying new composite materials.
Apex-angle-dependent resonances in triangular split ring resonators
Burnett, Max A
2016-01-01
Along with other frequency selective structures [1] (circles and squares), triangular split-ring resonators (TSRRs) only allow frequencies near the center resonant frequency to propagate. Further, TSRRs are attractive due to their small surface area [2], comparatively, and large quality factors (Q) factors as previously investigated by Gay-Balmaz, et al. [3]. In this work we examine the effects of varying the apex angle on the resonant frequency, the Q factor, and the phase shift imparted by the TSRR element within the GHz frequency regime.
On Mulholland Inequality and Dominance of Strict Triangular Norms
Petrík, Milan
Berlin: Springer, 2013 - (Bustince, H.; Fernandez, J.; Mesiar, R.; Calvo, T.), s. 187-195. (Advances in Intelligent Systems and Computing. 228). ISBN 978-3-642-39164-4. ISSN 2194-5357. [AGOP 2013. International Summer School on Aggregation Operators at the Public University of Navarra. Pamplona (ES), 16.07.2013-20.07.2013] R&D Projects: GA ČR GPP201/12/P055 Grant ostatní: GA MŠk(CZ) EE2.3.20.0051 Keywords : Mulholland inequality * Minkowski inequality * strict triangular norm * dominance relation Subject RIV: BA - General Mathematics
Bistable Chimera Attractors on a Triangular Network of Oscillator Populations
Martens, Erik Andreas
2010-01-01
. This triangular network is the simplest discretization of a continuous ring of oscillators. Yet it displays an unexpectedly different behavior: in contrast to the lone stable chimera observed in continuous rings of oscillators, we find that this system exhibits two coexisting stable chimeras. Both...... chimeras are, as usual, born through a saddle-node bifurcation. As the coupling becomes increasingly local in nature they lose stability through a Hopf bifurcation, giving rise to breathing chimeras, which in turn get destroyed through a homoclinic bifurcation. Remarkably, one of the chimeras reemerges by...
Tunable supercurrent in a triangular triple quantum dot system
The supercurrent in a triangular triple quantum dot system is investigated by using the nonequilibrium Green's function method. It is found that the sign of the supercurrent can be changed from positive to negative with increasing the strength of spin-flip scattering, resulting in the π-junction transition. The supercurrent and the π-junction transition are also modulated by tuning the system parameters such as the gate voltage and the interdot coupling. The tunable π-junction transition is explained in terms of the current carrying density of states. These results provide the ways of manipulating the supercurrent in a triple quantum dot system.
Mott transition and magnetism on the anisotropic triangular lattice
Acheche, S.; Reymbaut, A.; Charlebois, M.; Sénéchal, D.; Tremblay, A.-M.S.
2016-01-01
Spin-liquid behavior was recently suggested experimentally in the moderately one-dimensional organic compound $\\kappa$-H$_3$(Cat-EDT-TTF)$_2$. This compound can be modeled by the one-band Hubbard model on the anisotropic triangular lattice with $t^\\prime/t \\simeq 1.5$, where $t'$ is the minority hopping. It thus becomes important to extend previous studies, that were performed in the range $0 \\leq t'/t \\leq 1.2$, to find out whether there is a regime where Mott insulating behavior can be foun...
Triangular-slot monopole antenna for on-body communications
Martín Cantero, Alejandro
2014-01-01
ABSTRACT: The objective of this project is to optimize and redesign a Triangular monopole slot antenna designed to work in On-Body communications. Originally, the antenna was working in the 5.8 GHz ISM band and in the first steps of the design we had to modify the antenna to establish its resonant frequency in the 2.4 GHz band. Finally, we changed the antenna substrate to CuClad 217LX, since this substrate is more flexible and therefore more optimum for communications on the human body. Durin...
Wavelength Demultiplexer using Heterostructure Ring Resonators in Triangular Photonic Crystals
Mohammad Reza Rakhshani
2013-04-01
Full Text Available In this Paper a new type of wavelength demultiplexer using ring resonators in 2D triangular photonic crystal is presented. The designed demultiplexer contents two regions which each own a resonator. Two dielectric constants are used in this demultiplexer. These structures which are called hetero have the capability to be used in wavelength division multiplexing (WDM systems. The average transferred power for the two output channels is about 93%. The crosstalk between output channels was more than -18.5dB, also the overall size of the structure was about 144µm2 which is so appropriate for fabrication and integration.
Synthesis and Photocatalytic Activity of Ag3PO4 Triangular Prism
Pengyu Dong; Yan Hao; Peiyang Gao; Entian Cui; Qinfang Zhang
2015-01-01
Ag3PO4 triangular prism was synthesized by a facile chemical precipitation approach by simply adjusting external ultrasonic condition. The as-synthesized Ag3PO4 triangular prism was characterized by X-ray diffraction pattern (XRD), field emission scanning electron microscopy (SEM), fourier transform infrared (FTIR) spectra, and ultraviolet-visible diffuse reflectance (UV-vis DRS) absorption spectra. The photocatalytic activity of Ag3PO4 triangular prism was evaluated by photodegradation of or...
Approximation and geometric processing of digital images with adaptive triangular meshes
Vintimilla Burgos, Boris Xavier
2001-01-01
Esta tesis se ha enfocado en el desarrollo y evaluación de un conjunto de técnicas eficientes para generar y procesar mallas triangulares adaptativas obtenidas a partir de imágenes digitales.Tres objetivos diferentes han sido considerados: (1) aproximación de imágenes digitales con mallas triangulares adaptativas, (2) ejecución de operaciones típicas de procesamiento de imagen sobre mallas triangulares adaptativas y (3) obtención de imágenes digitales a partir de mallas triangulares adaptativ...
On the interference rejection capabilities of triangular antenna array for cellular base stations
Atat, Rachad
2012-03-01
In this paper, we present the performance analysis of the triangular antenna arrays in terms of the interference rejection capability. In this context, we derive an expression to calculate the spatial interference suppression coefficient for the triangular antenna array with variable number of antenna elements. The performance of the triangular antenna array has been compared with the circular antenna array with respect to interference suppression performance, steering beam pattern, beamwidth and directivity. Simulation results show that the triangular array with large number of elements produces a sharper beamwidth and better interference suppression performance than the circular antenna array. © 2012 IEEE.
Statistical Complexity in Traveling Densities
Lopez-Ruiz, Ricardo; Sanudo, Jaime
2009-01-01
In this work, we analyze the behavior of statistical complexity in several systems where two identical densities that travel in opposite direction cross each other. The crossing between two Gaussian, rectangular and triangular densities is studied in detail. For these three cases, the shape of the total density presenting an extreme value in complexity is found.
Utkin, Lev V; Chekh, Anatoly I; Zhuk, Yulia A
2016-08-01
Classification algorithms based on different forms of support vector machines (SVMs) for dealing with interval-valued training data are proposed in the paper. L2-norm and L∞-norm SVMs are used for constructing the algorithms. The main idea allowing us to represent the complex optimization problems as a set of simple linear or quadratic programming problems is to approximate the Gaussian kernel by the well-known triangular and Epanechnikov kernels. The minimax strategy is used to choose an optimal probability distribution from the set and to construct optimal separating functions. Numerical experiments illustrate the algorithms. PMID:27179616
Herzberg Circuit and Berry's Phase in Chirality-based Coded Qubit in a Triangular Triple Quantum Dot
Hsieh, Chang-Yu; Rene, Alexandre; Hawrylak, Pawel
2011-01-01
We present a theoretical proposal for the Herzberg circuit and controlled accumulation of Berry's phase in a chirality-based coded qubit in a triangular triple quantum dot molecule with one electron spin each. The qubit is encoded in the two degenerate states of a three spin complex with total spin $S=1/2$. Using a Hubbard and Heisenberg model the Herzberg circuit encircling the degeneracy point is realized by adiabatically tuning the successive on-site energies of quantum dots and tunnel cou...
Triangular nanobeam photonic cavities in single crystal diamond
Bayn, Igal; Salzman, Joseph; Kalish, Rafi
2011-01-01
Diamond photonics provides an attractive architecture to explore room temperature cavity quantum electrodynamics and to realize scalable multi-qubit computing. Here we review the present state of diamond photonic technology. The design, fabrication and characterization of a novel triangular cross section nanobeam cavity produced in a single crystal diamond is demonstrated. The present cavity design, based on a triangular cross section allows vertical confinement and better signal collection efficiency than that of slab-based nanocavities, and eliminates the need for a pre-existing membrane. The nanobeam is fabricated by Focused-Ion-Beam (FIB) patterning. The cavity is characterized by a confocal photoluminescence. The modes display quality factors of Q ~220 and are deviated in wavelength by only ~1.7nm from the NV- color center zero phonon line (ZPL). The measured results are found in good agreement with 3D Finite-Difference-Time-Domain (FDTD) calculations. A more advanced cavity design with Q=22,000 is model...
Triangular nanobeam photonic cavities in single-crystal diamond
Diamond photonics provides an attractive architecture to explore room temperature cavity quantum electrodynamics and to realize scalable multi-qubit computing. Here, we review the present state of diamond photonic technology. The design, fabrication and characterization of a novel nanobeam cavity produced in a single crystal diamond are demonstrated. The present cavity design, based on a triangular cross-section, allows vertical confinement and better signal collection efficiency than that of slab-based nanocavities and eliminates the need for a pre-existing membrane. The nanobeam is fabricated by focused-ion-beam (FIB) patterning. The cavity is characterized by confocal photoluminescence. The modes display quality factors of Q∼220 and deviate in wavelength by only ∼1.7 nm from the nitrogen-vacancy (NV-) color center zero phonon line (ZPL). The measured results are found to be in good agreement with three-dimensional finite-difference-time-domain (FDTD) calculations. A more advanced cavity design with Q=22 000 is modeled, showing the potential for high-Q implementations using the triangular geometry. The prospects of this concept and its application in spin non-demolition measurement and quantum computing are discussed.
Triangular Black Phosphorus Atomic Layers by Liquid Exfoliation
Seo, Soonjoo; Lee, Hyun Uk; Lee, Soon Chang; Kim, Yooseok; Kim, Hyeran; Bang, Junhyeok; Won, Jonghan; Kim, Youngjun; Park, Byoungnam; Lee, Jouhahn
2016-03-01
Few-layer black phosphorus (BP) is the most promising material among the two-dimensional materials due to its layered structure and the excellent semiconductor properties. Currently, thin BP atomic layers are obtained mostly by mechanical exfoliation of bulk BP, which limits applications in thin-film based electronics due to a scaling process. Here we report highly crystalline few-layer black phosphorus thin films produced by liquid exfoliation. We demonstrate that the liquid-exfoliated BP forms a triangular crystalline structure on SiO2/Si (001) and amorphous carbon. The highly crystalline BP layers are faceted with a preferred orientation of the (010) plane on the sharp edge, which is an energetically most favorable facet according to the density functional theory calculations. Our results can be useful in understanding the triangular BP structure for large-area applications in electronic devices using two-dimensional materials. The sensitivity and selectivity of liquid-exfoliated BP to gas vapor demonstrate great potential for practical applications as sensors.
Corrosion processes of triangular silver nanoparticles compared to bulk silver
Keast, V. J., E-mail: vicki.keast@newcastle.edu.au; Myles, T. A. [University of Newcastle, School of Mathematical and Physical Sciences (Australia); Shahcheraghi, N.; Cortie, M. B. [University of Technology Sydney, Institute for Nanoscale Technology (Australia)
2016-02-15
Excessive corrosion of silver nanoparticles is a significant impediment to their use in a variety of potential applications in the biosensing, plasmonic and antimicrobial fields. Here we examine the environmental degradation of triangular silver nanoparticles (AgNP) in laboratory air. In the early stages of corrosion, transmission electron microscopy shows that dissolution of the single-crystal, triangular, AgNP (side lengths 50–120 nm) is observed with the accompanying formation of smaller, polycrystalline Ag particles nearby. The new particles are then observed to corrode to Ag{sub 2}S and after 21 days nearly full corrosion has occurred, but some with minor Ag inclusions remaining. In contrast, a bulk Ag sheet, studied in cross section, showed an adherent corrosion layer of only around 20–50 nm in thickness after over a decade of being exposed to ambient air. The results have implications for antibacterial properties and ecotoxicology of AgNP during corrosion as the dissolution and reformation of Ag particles during corrosion will likely be accompanied by the release of Ag{sup +} ions.
IN SEARCH OF IDEAL FORM- RATIO OF TRIANGULAR CHANNEL
B. C. DAS
2014-11-01
Full Text Available In Search of Ideal Form-Ratio of Triangular Channel. Cross-sectional form of a natural channel is a two dimensional variable which is thoroughly studied by scholars from different fields on natural sciences like hydrology, geology, geomorphology, etc. Average river channels tend to develop their channel-cross sectional form in a way to produce an approximate equilibrium between the channel and the water and sediment it transport. But how far it is deviated from the ideal cross-sectional form can only be determined by knowing the ideal form which was calculated by Hickin for rectangular channel. This ideal cross-sectional form of ‘maximum efficiency’ is virtually a theoretical one and attaining of which the river transports its water and load with least friction with its bed. ‘Ideal form ratio’ provides numerical tools for triangular channel to determine the degree of deviation of a cross-sectional form from that of an ideal one.
Monte Carlo renormalization: Test on the triangular Ising model
We test the performance of the Monte Carlo renormalization method using the Ising model on the triangular lattice. We apply block-spin transformations which allow for adjustable parameters so that the transformation can be optimized. This optimization takes into account the relation between corrections to scaling and the location of the fixed point. To this purpose we determine corrections to scaling of the triangular Ising model with nearest- and next-nearest-neighbor interactions, by means of transfer matrix calculations and finite-size scaling. We find that the leading correction to scaling just vanishes for the nearest-neighbor model. However, the fixed point of the commonly used majority-rule block-spin transformation lies far away from the nearest-neighbour critical point. This raises the question whether the majority rule is suitable as a renormalization transformation, because corrections to scaling are supposed to be absent at the fixed point. We define a modified block-spin transformation which shifts the fixed point back to the vicinity of the nearest-neighbour critical Hamiltonian. This modified transformation leads to results for the Ising critical exponents that converge faster, and are more accurate than those obtained with the majority rule. (author)
Corrosion processes of triangular silver nanoparticles compared to bulk silver
Excessive corrosion of silver nanoparticles is a significant impediment to their use in a variety of potential applications in the biosensing, plasmonic and antimicrobial fields. Here we examine the environmental degradation of triangular silver nanoparticles (AgNP) in laboratory air. In the early stages of corrosion, transmission electron microscopy shows that dissolution of the single-crystal, triangular, AgNP (side lengths 50–120 nm) is observed with the accompanying formation of smaller, polycrystalline Ag particles nearby. The new particles are then observed to corrode to Ag2S and after 21 days nearly full corrosion has occurred, but some with minor Ag inclusions remaining. In contrast, a bulk Ag sheet, studied in cross section, showed an adherent corrosion layer of only around 20–50 nm in thickness after over a decade of being exposed to ambient air. The results have implications for antibacterial properties and ecotoxicology of AgNP during corrosion as the dissolution and reformation of Ag particles during corrosion will likely be accompanied by the release of Ag+ ions
Fissioned triangular schemes via sharply 3-transitive groups
Ma, Jianmin
2011-01-01
n [D. de Caen, E.R. van Dam. Fissioned triangular schemes via the cross-ratio, {Europ. J. Combin.}, 22 (2001) 297-301], de Caen and van Dam constructed a fission scheme $\\FT(q+1)$ of the triangular scheme on $\\PG(1,q)$. This fission scheme comes from the naturally induced action of $\\PGL(2,q)$ on the 2-element subsets of $\\PG(1,q)$. The group $\\PGL(2,q)$ is one of two infinite families of finite sharply 3-transitive groups. The other such family $\\Mq(q)$ is a "twisted" version of $\\PGL(2,q)$, where $q$ is an even power of an odd prime. The group $\\PSL(2,q)$ is the intersection of $\\PGL(2,q)$ and $\\Mq(q)$. In this paper, we investigate the association schemes coming from the actions of $\\PSL(2,q)$, $\\Mq(q)$ and $\\PML(2,q)$, respectively. Through the conic model introduced in [H.D.L. Hollmann, Q. Xiang. Association schemes from the actions of $\\PGL(2, q) $ fixing a nonsingular conic, {J. Algebraic Combin.}, 24 (2006) 157-193], we introduce an embedding of $\\PML(2,q)$ into $\\PML(3,q)$. For each of the three grou...
Clar Sextet Analysis of Triangular, Rectangular, and Honeycomb Graphene Antidot Lattices
Petersen, Rene; Pedersen, Thomas Garm; Jauho, Antti-Pekka
2011-01-01
triangular, and the honeycomb lattice. It is found that the lattice geometry plays a crucial role for size of the band gap the triangular arrangement displays always a shable gap, while for the other types only particular hole separations lead to a large gap. This observation is explained using, Clear sextet...
Self-assembly of triangular quantum dots on (111)A substrates by droplet epitaxy
We report the self-assembly of triangular GaAs quantum dots (QDs) on (111)A substrates using droplet epitaxy. Shape transition from hexagonal to triangular QDs is observed with increasing crystallizing temperature. The mechanism of the morphological change is discussed in terms of different growth rates of step edges on a (111)A substrate
Electron sharing and anion-π recognition in molecular triangular prisms.
Schneebeli, Severin T; Frasconi, Marco; Liu, Zhichang; Wu, Yilei; Gardner, Daniel M; Strutt, Nathan L; Cheng, Chuyang; Carmieli, Raanan; Wasielewski, Michael R; Stoddart, J Fraser
2013-12-01
Stacking on a full belly: Triangular molecular prisms display electron sharing among their triangularly arranged naphthalenediimide (NDI) redox centers. Their electron-deficient cavities encapsulate linear triiodide anions, leading to the formation of supramolecular helices in the solid state. Chirality transfer is observed from the six chiral centers of the filled prisms to the single-handed helices. PMID:24227594
Alsufyani, Mohammed A.; Robin Unger
2011-01-01
Temporal triangular alopecia (TTA), also known as congenital triangular alopecia, is a nonscarring, noninflammatroy, circumscribed form of alopecia. TTA has been associated with several disorders, such as Phakomatosis Pigmentovascularis. Hair restoration surgery using follicular unit transplantation has been a successful treatment modality for TTA. Herein we report such a success that was sustained for over six years.
Robin Unger
2011-01-01
Full Text Available Temporal triangular alopecia (TTA, also known as congenital triangular alopecia, is a nonscarring, noninflammatroy, circumscribed form of alopecia. TTA has been associated with several disorders, such as Phakomatosis Pigmentovascularis. Hair restoration surgery using follicular unit transplantation has been a successful treatment modality for TTA. Herein we report such a success that was sustained for over six years.
Constructing triangular patch by basic approximation operator plus additional interpolation operator
ZHANG Caiming; Jl Xiuhua; YANG Xingqiang
2005-01-01
A new method for constructing triangular patches is presented. The triangular patch that interpolates the given boundary curves and cross-boundary slopes is constructed by a basic approximation operator plus an additional interpolation operator. The basic approximation operator is constructed by a polynomial surface of degree five which approximates the given interpolation conditions. The additional interpolation operator is formed by the side-vertex method. The basic and the additional operators have different roles in constructing the triangular patch: the first one makes the triangular patch approximate the given interpolation conditions with a polynomial approximation precision of degree five, while the second one makes it satisfy the given interpolation conditions. The triangular patch reproduces polynomial surfaces of degree five. Comparison results of the new method with the other two methods are included.
Real Time Clustering of Time Series Using Triangular Potentials
Aldo Pacchiano
2015-01-01
Full Text Available Motivated by the problem of computing investment portfolio weightin gs we investigate various methods of clustering as alternatives to traditional mean-v ariance approaches. Such methods can have significant benefits from a practical point of view since they remove the need to invert a sample covariance matrix, which can suffer from estimation error and will almost certainly be non-stationary. The general idea is to find groups of assets w hich share similar return characteristics over time and treat each group as a singl e composite asset. We then apply inverse volatility weightings to these new composite assets. In the course of our investigation we devise a method of clustering based on triangular potentials and we present as sociated theoretical results as well as various examples based on synthetic data.
Model of Vertical Product Differentiation Based on Triangular Distribution
HU Jian-bing; WANG He-ping; SHEN Yun-hong
2007-01-01
Supposing that the consumer preference complies with triangular distribution instead of uniform distribution, we establish the model of vertical product differentiation. The simulation shows that there exists stable equilibrium along with unstable equilibrium. In stable equilibrium, high quality products gain an advantage over low quality products. In unstable equilibrium, the former does not possess an apparent advantage in competition, likely to be at a disadvantage. In order to evolve from unstable equilibrium to stable equilibrium, it is necessary for firms to solve such problems as high prices and consumers' perception of scarcity on product qualities. In general, both product qualities and firm profits increase with the consuming capacity and quality perception, and the latter more rapidly.
A flat triangular shell element with Loof nodes
Poulsen, Peter Noe; Damkilde, Lars
1996-01-01
triangular shell element is established by a combination of a new plate bending element DKTL and the well-known linear membrane strain element LST, and for this element the above-mentioned deficiences are avoided. The plate bending element DKTL is based on Discrete Kirchhoff Theory and Loof nodes. The nodal......In the formulation of flat shell elements it is difficult to achieve inter-element compatibility between membrane and transverse displacements for non-coplanar elements. Many elements lack proper nodal degrees of freedom to model intersections making the assembly of elements troublesome. A flat...... configuration of the element is similar to the SemiLoof element, and the formulation is an improvement of a previous formulation. The element is used for both linear statics, linear buckling and geometrical non-linear analysis, and numerical examples are presented to show the robustness, accuracy and quick...
Magnetic anisotropy study of triangular-shaped Co nanostructures
Imperia, P. [Hahn Meitner Institut, Glienicker Strasse 100, 14109 Berlin (Germany)], E-mail: paolo.imperia@ansto.gov.au; Kandulski, W.; Kosiorek, A. [CESAR Research Center, Ludwig-Erhard-Allee 2, 53175 Bonn (Germany); Glaczynska, H. [CESAR Research Center, Ludwig-Erhard-Allee 2, 53175 Bonn (Germany); Department of Macromolecular Physics, Adam Mickiewicz University, Umultowska 85, Poznan (Poland); Maletta, H. [Hahn Meitner Institut, Glienicker Strasse 100, 14109 Berlin (Germany); Giersig, M. [CESAR Research Center, Ludwig-Erhard-Allee 2, 53175 Bonn (Germany)
2008-11-15
Atomic force microscopy (AFM), X-ray magnetic circular dichroism (XMCD), magnetic force microscopy (MFM) and vibrating sample magnetometry (VSM) have been used to measure the magnetic and geometrical characteristics of triangular-shaped Co structures of lateral size 730 nm and thickness 32 nm, prepared by nanosphere lithography (NSL). Evidence of in-plane six-fold magnetic anisotropy induced by the symmetry of the structure has been found. By means of XMCD measurements, performed at remanence after applying a pulsed field, a structure rotation angle-dependent oscillation of about 15% with a periodicity of 60 deg. has been observed for both the orbital and spin moments. Furthermore, the system exhibits the angular hysteresis effect. The magnetic measurements performed by MFM show a reduction of the magnetic configurations to only two states, one quasi-single domain Y state and second, a combination of vortex and Y state.
Acoustic control study of turbofan nozzles with triangular chevrons
Grigore CICAN
2014-03-01
Full Text Available This paper has a small part dealing with the notion of chevron and the process that helps reducing the noise pollution. Based on the gas dynamics and the geometrical parameters of the turbofan jet engine a model of CFD data processing is created. In this process the influence of chevrons on acoustic wave intensity produced by the jet is observed by analyzing this process. A series of tests have been made on 10 si 20 lobed chevrons. The combination between them and the 7 resulting cases have been studied, namely the triangular chevrons in order to settle the influence of the geometrical parameters on the flow and on the jet acoustics. Finally the contribution of the chevrons in noise pollution reduction has been highlighted.
Success Factors of Biotechnology Industry Based on Triangular Fuzzy Number
Lei; LEI
2013-01-01
Based on the theory of competitive advantage and value chain, this paper establishes the indicator system, and develop the strategic framework using the fuzzy Delphi method. Then the triangular fuzzy number model is established using Fuzzy Analytic Hierarchy Process, and the key factors influencing biotechnology industry are extracted. The results show that in terms of weight, the key factors influencing the success of biotechnology industry are sequenced as follows: "open innovation capacity", "quality and cost control ability", "advanced customer-oriented product manufacturing capacity", "technology R & D personnel’s capacity", "brand image building capacity", "logistics and sales capacity", "grasping the market demand trends". The manufacturers and government decision-making body can use this as the basis, to promote the development of the biotechnology industry.
CFD analysis of flow field in a triangular rod bundle
The flow field was investigated in subchannels of VVER-440 pressurized water cooled reactors' fuel assemblies (triangular lattice, P/D = 1.35). Impacts of the mesh resolution and turbulence model were studied in order to obtain guidelines for CFD calculations of VVER-440 rod bundles. Results were compared to measurement data published by Trupp and Azad in 1975. The study pointed out that RANS method with BSL Reynolds stress model using a sufficient fine grid can provide an accurate prediction for the turbulence quantities in this lattice. Applying the experiences of the sensitivity study thermal hydraulic processes were investigated in VVER-440 rod bundle sections. Based on the examinations the spacer grids have important effects on the cross flows, axial velocity and outlet temperature distribution of subchannels therefore they have to be modeled satisfactorily in CFD calculations.
Notched Triangular Microstrip Antenna for Dual-Frequency Operation
江轶慧; 钟顺时
2003-01-01
A novel equilateral triangular patch with a rectangular notch etched to one radiating edge on organic magnetic substrate is proposed for dual frequency operation. Both operations of these dual frequencies arise from the perturbation of TM10 and TM11 mode by simply cutting a rectangular notch at the patch bottom. Simulations and experiments have shown the validity of this design. Using an organic magnetic material as the substrate, the antenna exhibits a broader bandwidth of 5.5% and 4.7% at dual-frequencies 1.56GHz and 2.45GHz, respectively, as well as a reduced size compared to the dual-frequency patch antennas on non-magnetic material.
Friction Factor Measurements in an Equally Spaced Triangular Tube Array
Vassallo P, Symolon P
2007-03-19
Friction factor data for adiabatic cross-flow of water in a staggered tube array was obtained over a Reynolds number range (based on hydraulic diameter and gap velocity) of about 10,000 to 250,000. The tubes were 12.7mm (0.5 inch) outer diameter, in a uniformly spaced triangular arrangement with a pitch-to-diameter ratio of 1.5. The friction factor was compared to several literature correlations, and was found to be best matched by the Idelchik correlation. Other correlations were found to vary significantly from the test data. Based on the test data, a new correlation is proposed for this tube bundle geometry which covers the entire Reynolds number range tested.
A Generalization of the Formula for the Triangular Number of the Sum and Product of Natural Numbers
Asiru, M. A.
2008-01-01
This note generalizes the formula for the triangular number of the sum and product of two natural numbers to similar results for the triangular number of the sum and product of "r" natural numbers. The formula is applied to derive formula for the sum of an odd and an even number of consecutive triangular numbers.
M. Carla Aragoni
2007-01-01
Full Text Available The 3 centre-4 electrons (3c-4e and the donor/acceptor or charge-transfer models for the description of the chemical bond in linear three-body systems, such as I3– and related electron-rich (22 shell electrons systems, are comparatively discussed on the grounds of structural data from a search of the Cambridge Structural Database (CSD. Both models account for a total bond order of 1 in these systems, and while the former fits better symmetric systems, the latter describes better strongly asymmetric situations. The 3c-4e MO scheme shows that any linear system formed by three aligned closed-shell species (24 shell electrons overall has reason to exist provided that two electrons are removed from it to afford a 22 shell electrons three-body system: all combinations of three closed-shell halides and/or chalcogenides are considered here. A survey of the literature shows that most of these three-body systems exist. With some exceptions, their structural features vary continuously from the symmetric situation showing two equal bonds to very asymmetric situations in which one bond approaches to the value corresponding to a single bond and the second one to the sum of the van der Waals radii of the involved atoms. This indicates that the potential energy surface of these three-body systems is fairly flat, and that the chemical surrounding of the chalcogen/halogen atoms can play an important role in freezing different structural situations; this is well documented for the I3– anion. The existence of correlations between the two bond distances and more importantly the linearity observed for all these systems, independently on the degree of their asymmetry, support the state of hypervalency of the central atom.
Ground State of a Polaron in a Symmetric Triangular Quantum Well
ZHANG Ji-Ye; LIANG Xi-Xia
2006-01-01
@@ We study the effects of electron-phonon interaction on the electron ground state in a symmetric triangular quantum well, and calculate the ground state energy of an electron in the GaAs/Al0.96Ga0.04As triangular quantum well including the effects of the interaction between electrons and confined LO phonons by using a modified Lee-Low-Pines variational method. The electron wavefunction in the triangular well is chosen as the Airy function.The numerical results are given and discussed.
Dhayal, Rajendra S; Liao, Jian-Hong; Lin, Yan-Ru; Liao, Ping-Kuei; Kahlal, Samia; Saillard, Jean-Yves; Liu, C W
2013-03-27
An unprecedented air-stable, nanospheric polyhydrido copper cluster, [Cu20H11(S2P(O(i)Pr)2)9] (1H), which is the first example of an elongated triangular orthobicupola array of Cu atoms having C3h symmetry, was synthesized and characterized. Its composition was primarily determined by electrospray ionization mass spectrometry, and it was fully characterized by (1)H, (2)H, and (31)P NMR spectroscopy and single-crystal X-ray diffraction (XRD). The structure of complex 1H can be expressed in terms of a trigonal-bipyramidal [Cu2H5](3-) unit anchored within an elongated triangular orthobicupola containing 18 Cu atoms, which is further stabilized by 18 S atoms from nine dithiophosphate ligands and six capping hydrides. The positions of the 11 hydrides revealed by low temperature XRD were supported by a density functional theory investigation on the simplified model [Cu20H11(S2PH2)9] with C3h symmetry. 1H is capable of releasing H2 gas upon irradiation with sunlight, under mild thermal conditions (65 °C), or in the presence of acids at room temperature. PMID:23472670
Multi-domain electromagnetic absorption of triangular quantum rings
Sitek, Anna; Thorgilsson, Gunnar; Gudmundsson, Vidar; Manolescu, Andrei
2016-06-01
We present a theoretical study of the unielectronic energy spectra, electron localization, and optical absorption of triangular core–shell quantum rings. We show how these properties depend on geometric details of the triangle, such as side thickness or corners’ symmetry. For equilateral triangles, the lowest six energy states (including spin) are grouped in an energy shell, are localized only around corner areas, and are separated by a large energy gap from the states with higher energy which are localized on the sides of the triangle. The energy levels strongly depend on the aspect ratio of the triangle sides, i.e., thickness/length ratio, in such a way that the energy differences are not monotonous functions of this ratio. In particular, the energy gap between the group of states localized in corners and the states localized on the sides strongly decreases with increasing the side thickness, and then slightly increases for thicker samples. With increasing the thickness the low-energy shell remains distinct but the spatial distribution of these states spreads. The behavior of the energy levels and localization leads to a thickness-dependent absorption spectrum where one transition may be tuned in the THz domain and a second transition can be tuned from THz to the infrared range of electromagnetic spectrum. We show how these features may be further controlled with an external magnetic field. In this work the electron–electron Coulomb repulsion is neglected.
Thermoviscoplastic analysis of fibrous periodic composites using triangular subvolumes
Walker, Kevin P.; Freed, Alan D.; Jordan, Eric H.
1993-01-01
The nonlinear viscoplastic behavior of fibrous periodic composites is analyzed by discretizing the unit cell into triangular subvolumes. A set of these subvolumes can be configured by the analyst to construct a representation for the unit cell of a periodic composite. In each step of the loading history, the total strain increment at any point is governed by an integral equation which applies to the entire composite. A Fourier series approximation allows the incremental stresses and strains to be determined within a unit cell of the periodic lattice. The nonlinearity arising from the viscoplastic behavior of the constituent materials comprising the composite is treated as fictitious body force in the governing integral equation. Specific numerical examples showing the stress distributions in the unit cell of a fibrous tungsten/copper metal matrix composite under viscoplastic loading conditions are given. The stress distribution resulting in the unit cell when the composite material is subjected to an overall transverse stress loading history perpendicular to the fibers is found to be highly heterogeneous, and typical homogenization techniques based on treating the stress and strain distributions within the constituent phases as homogeneous result in large errors under inelastic loading conditions.
MULTIPLICATIVE GROUP AUTOMORPHISMS OF INVERTIBLE UPPER TRIANGULAR MATRICES OVER FIELDS
2000-01-01
Suppose F is a field of characteristic not 2 and F* its multiplicative group.Let T* n (F) be the multiplicative group of invertible upper triangular n × n matrices over F and ST±n(F) its subgroup {(aij) ∈ T * n(F)｜aii = +1,i}.This paper proves that f:T * n(F) → T * n(F) is a group automorphism if and only if there exist a matrix Q in T * n(F) and a field automorphism σ of F such that either σ -1 f(A) = ψ(A)QAσQ-1,A = (aij) ∈ T * n(F) or f(A) = ψ(A-1)Q[J(Aσ)-TJ]Q-1,A =(aij) ∈ T * n(F),where Aσ = (σ(aij)),A-T is the transpose inverse of A,J = n∑i=1 Ei n+1-i,and ψ :i=1 T * n(F) → F* is a homomorphism which satisfies {ψ(xIn)σ(x)｜x ∈ F*} = F* and {x ∈F*｜ψ(xIn)σ(x) = 1} = {1}.Simultaneously,they also determine the automorphisms of ST±n(F).
Evidence for Triangular D_3h Symmetry in 12C
Marin-Lambarri, D J; Freer, M; Gai, M; Kokalova, Tz; Parker, D J; Wheldon, C
2014-01-01
We report a measurement of a new high spin Jp = 5- state at 22.4(0.2) MeV in 12C which fits very well to the predicted (ground state) rotational band of an oblate equilateral triangular spinning top with a D_3h symmetry characterized by the sequence 0+, 2+, 3-, 4+/-, 5- with almost degenerate 4+ and 4- (parity doublet) states. Such a D_3h symmetry was observed in triatomic molecules and it is observed here for the first time in nuclear physics. We discuss a classification of other rotation-vibration bands in 12C such as the (0+) Hoyle band and the (1-) bending mode band and suggest measurements in search of the predicted ("missing") states that may shed new light on clustering in 12C and light nuclei. In particular the observation (or non-observation) of the predicted ("missing") states in the Hoyle band will allow us to conclude the geometrical arrangement of the three alpha-particle composing the Hoyle state at 7.654 MeV in 12C.
Agglomerative percolation on the Bethe lattice and the triangular cactus
Chae, Huiseung; Yook, Soon-Hyung; Kim, Yup
2013-08-01
Agglomerative percolation (AP) on the Bethe lattice and the triangular cactus is studied to establish the exact mean-field theory for AP. Using the self-consistent simulation method based on the exact self-consistent equations, the order parameter P∞ and the average cluster size S are measured. From the measured P∞ and S, the critical exponents βk and γk for k = 2 and 3 are evaluated. Here, βk and γk are the critical exponents for P∞ and S when the growth of clusters spontaneously breaks the Zk symmetry of the k-partite graph. The obtained values are β2 = 1.79(3), γ2 = 0.88(1), β3 = 1.35(5) and γ3 = 0.94(2). By comparing these exponents with those for ordinary percolation (β∞ = 1 and γ∞ = 1), we also find β∞ γ3 > γ2. These results quantitatively verify the conjecture that the AP model belongs to a new universality class if the Zk symmetry is broken spontaneously, and the new universality class depends on k.
Agglomerative percolation on the Bethe lattice and the triangular cactus
Agglomerative percolation (AP) on the Bethe lattice and the triangular cactus is studied to establish the exact mean-field theory for AP. Using the self-consistent simulation method based on the exact self-consistent equations, the order parameter P∞ and the average cluster size S are measured. From the measured P∞ and S, the critical exponents βk and γk for k = 2 and 3 are evaluated. Here, βk and γk are the critical exponents for P∞ and S when the growth of clusters spontaneously breaks the Zk symmetry of the k-partite graph. The obtained values are β2 = 1.79(3), γ2 = 0.88(1), β3 = 1.35(5) and γ3 = 0.94(2). By comparing these exponents with those for ordinary percolation (β∞ = 1 and γ∞ = 1), we also find β∞ 3 2 and γ∞ > γ3 > γ2. These results quantitatively verify the conjecture that the AP model belongs to a new universality class if the Zk symmetry is broken spontaneously, and the new universality class depends on k. (paper)
Quantum electric-dipole liquid on a triangular lattice
Shen, Shi-Peng; Wu, Jia-Chuan; Song, Jun-Da; Sun, Xue-Feng; Yang, Yi-Feng; Chai, Yi-Sheng; Shang, Da-Shan; Wang, Shou-Guo; Scott, James F.; Sun, Young
2016-01-01
Geometric frustration and quantum fluctuations may prohibit the formation of long-range ordering even at the lowest temperature, and therefore liquid-like ground states could be expected. A good example is the quantum spin liquid in frustrated magnets. Geometric frustration and quantum fluctuations can happen beyond magnetic systems. Here we propose that quantum electric-dipole liquids, analogues of quantum spin liquids, could emerge in frustrated dielectrics where antiferroelectrically coupled electric dipoles reside on a triangular lattice. The quantum paraelectric hexaferrite BaFe12O19 with geometric frustration represents a promising candidate for the proposed electric-dipole liquid. We present a series of experimental lines of evidence, including dielectric permittivity, heat capacity and thermal conductivity measured down to 66 mK, to reveal the existence of an unusual liquid-like quantum phase in BaFe12O19, characterized by itinerant low-energy excitations with a small gap. The possible quantum liquids of electric dipoles in frustrated dielectrics open up a fresh playground for fundamental physics. PMID:26843363
Behaviour of Lagrangian triangular mixed fluid finite elements
S Gopalakrishnan; G Devi
2000-02-01
The behaviour of mixed fluid finite elements, formulated based on the Lagrangian frame of reference, is investigated to understand the effects of locking due to incompressibility and irrotational constraints. For this purpose, both linear and quadratic mixed triangular fluid elements are formulated. It is found that there exists a close relationship between the penalty finite element approach that uses reduced/selective numerical integration to alleviate locking, and the mixed finite element approach. That is, performing reduced/selective integration in the penalty approach amounts to reducing the order of pressure interpolation in the mixed finite element approach for obtaining similar results. A number of numerical experiments are performed to determine the optimum degree of interpolation of both the mean pressure and the rotational pressure in order that the twin constraints are satisfied exactly. For this purpose, the benchmark solution of the rigid rectangular tank is used. It is found that, irrespective of the degree of mean and the rotational pressure interpolation, the linear triangle mesh, with or without central bubble function (incompatible mode), locks when both the constraints are enforced simultaneously. However, for quadratic triangle, linear interpolation of the mean pressure and constant rotational pressure ensures exact satisfaction of the constraints and the mesh does not lock. Based on the results obtained from the numerical experiments, a number of important conclusions are arrived at.
Improved Radiation and Bandwidth of Triangular and Star Patch Antenna
M. Ramkumar Prabhu
2012-06-01
Full Text Available This study presents a hexagonal shape Defected Ground Structure (DGS implemented on two element triangular patch microstrip antenna array. The radiation performance of the antenna is characterized by varying the geometry and dimension of the DGS and also by locating the DGS at specific position which were simulated. Simulation and measurement results have verified that the antenna with DGS had improved the antenna without DGS. Measurement results of the hexagonal DGS have axial ratio bandwidth enhancement of 10 MHz, return loss improvement of 35%, mutual coupling reduction of 3 dB and gain enhancement of 1 dB. A new wideband and small size star shaped patch antenna fed capacitively by a small diamond shape patch is proposed. To enhance the impedance bandwidth, posts are incorporated under the patch antenna. HFSS high frequency simulator is employed to analyze the proposed antenna and simulated results on the return loss, the E- and H-plane radiation patterns and Gain of the proposed antenna are presented at various frequencies. The antenna is able to achieve in the range of 4-8.8 GHz an impedance bandwidth of 81% for return loss of less than-10 dB.
LIU Li-min(刘立民); LIU Han-long(刘汉龙); LIAN Chuan-jie(连传杰)
2003-01-01
The application of the finite layer & triangular prism element method to the 3D ground subsidence and stress analysis caused by mining is presented. The layer elements and the triangular prism elements have been alternatively used in the numerical simulation system, the displacement pattern, strain matrix, elastic matrix, stiffness matrix, load matrix and the stress matrix of the layer element and triangular prism element have been presented. By means of the Fortran90 programming language, a numerical simulation system based on finite layer & triangular prism element have been built up, and this system is suitable for subsidence prediction and stress analysis of all mining condition and mining methods. Comparing with the infinite element method, this approach dramatically reduces the size of the set of equations that need to be solved, and greatly reduces the amount of data preparation required. It not only saves the internal storage, and the computation time, but also decreases the cost.
Two-dimensional orthogonal DCT expansion in triangular and trapezoid regions
Pei, Soo-Chang; Ding, Jian-Jiun; Lee, Tzu-Heng Henry
2010-07-01
It is known that the 2-D DCT basis is complete and orthogonal in a rectangular region. In this paper, we introduce the way to generate the complete and orthogonal 2-D DCT basis in a trapezoid region or a triangular region without using the complicated Gram-Schmidt method. Moreover, since a polygon can be decomposed several triangular regions, the proposed method is also suitable for the polygonal region. Our algorithm can much generalize the JPEG algorithm. Instead of dividing an image into 8 by 8 blocks, we can divide an image into trapezoid or triangular regions and then transform and code each of them. In addition to the DCT basis, our method can also be used for generating the 2-D complete and orthogonal DFT basis, KLT basis, Legendre basis, Hadamard (Walsh) basis, and polynomial basis in the trapezoid and triangular regions.
Constructal optimization for a solid-gas reactor based on triangular element
2008-01-01
Entropy generation minimization for heat and mass transfer process in a solid-gas reactor is carried out based on constructal theory by using triangular elemental area. The aspect ratio of the triangular elemental area is optimized under constraint conditions. A number of optimal triangular elements are assembled to a new large rectangular area, which is optimised again. The procedure is repeated until the control-volume is covered, and the complete analytical results are obtained. The effects of some parameters on minimum entropy generation are analysed by nu-merical examples. The results show that smaller entropy generation can be ob-tained when the optimization for a given volume is carried out on the basis of tri-angular elements than those obtained on the basis of rectangular elements.
Tilted resonators in a triangular elastic lattice: chirality, Bloch waves and negative refraction
Tallarico, Domenico; Movchan, Alexander B; Colquitt, Daniel J
2016-01-01
We consider a vibrating triangular mass-truss lattice whose unit cell contains a resonator of a triangular shape. The resonators are connected to the triangular lattice by trusses. Each resonator is tilted, i.e. it is rotated with respect to the triangular lattice's unit cell through an angle $\\vartheta_0$. This geometrical parameter is responsible for the emergence of a resonant mode in the Bloch spectrum for elastic waves and strongly affects the dispersive properties of the lattice. Additionally, the tilting angle $\\vartheta_0$ triggers the opening of a band gap at a Dirac-like point. We provide a physical interpretation of these phenomena and discuss the dynamical implications on elastic Bloch waves. The dispersion properties are used to design a structured interface containing tilted resonators which exhibit negative refraction and focussing, as in a "flat elastic lens".
Stress Distribution on Sandwich Structure with Triangular Grid Cores Suffered from Bending Load
Cui Xu
2015-01-01
Full Text Available Triangular grid reinforced by carbon fiber/epoxy (CF/EP was designed and manufactured. The sandwich structure was prepared by gluing the core and composite skins. The mechanical properties of the sandwich structure were investigated by the finite element analysis (FEA and three-point bending methods. The calculated bending stiffness and core shear stress were compared to the characteristics of a honeycomb sandwich structure. The results indicated that the triangular core ultimately failed under a bending load of 11000 N; the principal stress concentration was located at the loading region; and the cracks occurred on the interface top skin and triangular core. In addition, the ultimate stress bearing of the sandwich structure was 8828 N. The experimental results showed that the carbon fiber reinforced triangular grid was much stiffer and stronger than the honeycomb structure.
Triangular Alignment (TAME). A Tensor-based Approach for Higher-order Network Alignment
Mohammadi, Shahin [Purdue Univ., West Lafayette, IN (United States); Gleich, David F. [Purdue Univ., West Lafayette, IN (United States); Kolda, Tamara G. [Sandia National Laboratories (SNL-CA), Livermore, CA (United States); Grama, Ananth [Purdue Univ., West Lafayette, IN (United States)
2015-11-01
Network alignment is an important tool with extensive applications in comparative interactomics. Traditional approaches aim to simultaneously maximize the number of conserved edges and the underlying similarity of aligned entities. We propose a novel formulation of the network alignment problem that extends topological similarity to higher-order structures and provide a new objective function that maximizes the number of aligned substructures. This objective function corresponds to an integer programming problem, which is NP-hard. Consequently, we approximate this objective function as a surrogate function whose maximization results in a tensor eigenvalue problem. Based on this formulation, we present an algorithm called Triangular AlignMEnt (TAME), which attempts to maximize the number of aligned triangles across networks. We focus on alignment of triangles because of their enrichment in complex networks; however, our formulation and resulting algorithms can be applied to general motifs. Using a case study on the NAPABench dataset, we show that TAME is capable of producing alignments with up to 99% accuracy in terms of aligned nodes. We further evaluate our method by aligning yeast and human interactomes. Our results indicate that TAME outperforms the state-of-art alignment methods both in terms of biological and topological quality of the alignments.
Ciucu, Mihai
2005-01-01
We define the correlation of holes on the triangular lattice under periodic boundary conditions and study its asymptotics as the distances between the holes grow to infinity. We prove that the joint correlation of an arbitrary collection of lattice-triangular holes of even sides satisfies, for large separations between the holes, a Coulomb law and a superposition principle that perfectly parallel the laws of two dimensional electrostatics, with physical charges corresponding to holes, and the...
ON FUZZY TRANSPORTATION PROBLEM USING TRIANGULAR FUZZY NUMBERS WITH MODIFIED REVISED SIMPLEX METHOD
B. Ramesh Kumar; Murugesan, S.
2012-01-01
In this paper, we present a Modified Revised Simplex Method for minimizing fuzzy transportation problem of a Triangular Fuzzy Numbers. In which the supplies and demands are triangular fuzzy numbers. A parametric approach is used to obtain a fuzzy basic feasible solution with the help of Revised Simplex Method. We get optimal solution of fuzzy transportation problem in which number of constraints equal to number of occupied cells.
Ping Gao; Jun Yao; Weimin Wang; Huan Yang; Wenying Ma
2011-01-01
A sensitive volatile organic vapor sensor based on the LSPR properties of silver triangular nanoprisms is proposed in this paper. The triangular nanoprisms were fabricated by a nanosphere lithography (NSL) method. They have sharp vertices and edges, and are arranged in an ideal hexangular array. These characteristics ensure that they exhibit an excellent LSPR spectrum and a high sensitivity to the exterior environment changes. The LSPR spectra responding to ethanol vapor and four other volati...
Solution of two-dimensional Fredholm integral equation via RBF-triangular method
Amir Fallahzadeh
2012-04-01
Full Text Available In this paper, a new method is introduced to solve a two-dimensional Fredholm integral equation. The method is based on the approximation by Gaussian radial basis functions and triangular nodes and weights. Also, a new quadrature is introduced to approximate the two dimensional integrals which is called the triangular method. The results of the example illustrate the accuracy of the proposed method increases.
Development and Applications of a Flat Triangular Element for Thin Laminated Shells
Mohan, P
1997-01-01
Finite element analysis of laminated shells using a three-noded flat triangular shell element is presented. The flat shell element is obtained by combining the Discrete Kirchhoff Theory (DKT) plate bending element and a membrane element similar to the Allman element, but derived from the Linear Strain Triangular (LST) element. Though this combination has been employed in the literature for linear static analysis of laminated plates, the results presented are not...
Talabi, SO; Olunloyo, VOS; Kamiyo, OM; Collins, MW; Karayiannis, TG
2006-01-01
Triangular enclosures are typical configurations found in attic spaces of residential as well as industrial pitched-roof buildings. Previous studies on airflow within such spaces have focused on the laminar range. A numerical study has been carried out for time-dependent, two-dimensional low turbulence natural convection of air contained in the attic of a pitched roof of triangular cross-section. Two sets of boundary conditions have been considered: enclosure heated from the inclined walls an...
Analysis of the heat transfer in unsymmetrically heated triangular microchannels in slip flow regime
ZHU; Xun; LIAO; Qiang; XIN; Mingdao
2004-01-01
A theoretical analysis of heat transfer characteristics is presented for the fully developed laminar flow of the incompressible gas in the triangular microchannels heated unsymmetrically with constant axial heat flux. Through solving the energy equation with temperature jump boundary conditions in slip flow regime by virtue of a computationoriented method of the orthonormal function analysis, the dimensionless temperature profiles and the average Nusselt number for various thermal boundary conditions are obtained. The effects of Knudsen number, aspect ratio, and thermal boundary conditions on the heat transfer are discussed. The calculated results show that the orthonormal function method can be used to study the heat transfer characteristics of the unsymmetrically heated triangular microchannels. The average Nusselt number in triangular microchannels is lower for slip flow than for no-slip flow, and decreases with increasing Knudsen number. The aspect ratios and thermal boundary conditions of triangular microchannels have significant influences on the change of average Nusselt numbers with the increase in the Knudsen number. For the equilateral triangular microchannels, the decrease of the Nusselt number ratio due to temperature jump is smaller at large Knudsen number and larger at small Knudsen number on the boundary condition of bottom wall heated alone as compared with the one on the boundary condition of two heated hypotenuse walls. The correlations of the average Nusselt number with the Knudsen number for equilateral triangular microchannels are obtained.
TINITALY/01: a new Triangular Irregular Network of Italy
M. T. Pareschi
2007-06-01
Full Text Available A new Digital Elevation Model (DEM of the natural landforms of Italy is presented. A methodology is discussed to build a DEM over wide areas where elevation data from non-homogeneous (in density and accuracy input sources are available. The input elevation data include contour lines and spot heights derived from the Italian Regional topographic maps, satellite-based global positioning system points, ground based and radar altimetry data. Owing to the great heterogeneity of the input data density, the DEM format that better preserves the original accuracy is a Triangular Irregular Network (TIN. A Delaunay-based TIN structure is improved by using the DEST algorithm that enhances input data by evaluating inferred break-lines. Accordingly to this approach, biased distributions in slopes and elevations are absent. To prevent discontinuities at the boundary between regions characterized by data with different resolution a cubic Hermite blending weight S-shaped function is adopted. The TIN of Italy consists of 1.39×109 triangles. The average triangle area ranges from 12 to about 13000 m2 accordingly to different morphologies and different sources. About 50% of the model has a local average triangle area <500 m2. The vertical accuracy of the obtained DEM is evaluated by more than 200000 sparse control points. The overall Root Mean Square Error (RMSE is less than 3.5 m. The obtained national-scale DEM constitutes an useful support to carry out accurate geomorphological and geological investigations over large areas. The problem of choosing the best step size in deriving a grid from a TIN is then discussed and a method to quantify the loss of vertical information is presented as a function of the grid step. Some examples of DEM application are outlined. Under request, an high resolution stereo image database of the whole Italian territory (derived from the presented DEM is available to browse via internet.
Psyplot: Visualizing rectangular and triangular Climate Model Data with Python
Sommer, Philipp
2016-04-01
The development and use of climate models often requires the visualization of geo-referenced data. Creating visualizations should be fast, attractive, flexible, easily applicable and easily reproducible. There is a wide range of software tools available for visualizing raster data, but they often are inaccessible to many users (e.g. because they are difficult to use in a script or have low flexibility). In order to facilitate easy visualization of geo-referenced data, we developed a new framework called "psyplot," which can aid earth system scientists with their daily work. It is purely written in the programming language Python and primarily built upon the python packages matplotlib, cartopy and xray. The package can visualize data stored on the hard disk (e.g. NetCDF, GeoTIFF, any other file format supported by the xray package), or directly from the memory or Climate Data Operators (CDOs). Furthermore, data can be visualized on a rectangular grid (following or not following the CF Conventions) and on a triangular grid (following the CF or UGRID Conventions). Psyplot visualizes 2D scalar and vector fields, enabling the user to easily manage and format multiple plots at the same time, and to export the plots into all common picture formats and movies covered by the matplotlib package. The package can currently be used in an interactive python session or in python scripts, and will soon be developed for use with a graphical user interface (GUI). Finally, the psyplot framework enables flexible configuration, allows easy integration into other scripts that uses matplotlib, and provides a flexible foundation for further development.
Korobov, A.
2011-08-01
Discrete uniform Poisson-Voronoi tessellations of two-dimensional triangular tilings resulting from the Kolmogorov-Johnson-Mehl-Avrami (KJMA) growth of triangular islands have been studied. This shape of tiles and islands, rarely considered in the field of random tessellations, is prompted by the birth-growth process of Ir(210) faceting. The growth mode determines a triangular metric different from the Euclidean metric. Kinetic characteristics of tessellations appear to be metric sensitive, in contrast to area distributions. The latter have been studied for the variant of nuclei growth to the first impingement in addition to the conventional case of complete growth. Kiang conjecture works in both cases. The averaged number of neighbors is six for all studied densities of random tessellations, but neighbors appear to be mainly different in triangular and Euclidean metrics. Also, the applicability of the obtained results for simulating birth-growth processes when the 2D nucleation and impingements are combined with the 3D growth in the particular case of similar shape and the same orientation of growing nuclei is briefly discussed.
Alvarez-Ramírez, M; de Moraes, R V; Skea, J E F; Stuchi, T J
2012-01-01
We study the fourth-order stability of the triangular libration points in the absence of resonance for the three-body problem when the infinitesimal mass is affected not only by gravitation but also by light pressure from both primaries. A comprehensive summary of previous results is given, with some inaccuracies being corrected. The Lie triangle method is used to obtain the fourth-order Birkhoff normal form of the Hamiltonian, and the corresponding complex transformation to pre-normal form is given explicitly. We obtain an explicit expression for the determinant required by the Arnold-Moser theorem, and show that it is a rational function of the parameters, whose numerator is a fifth-order polynomial in the mass parameter. Particular cases where this polynomial reduces to a quartic are described. Our results reduce correctly to the purely gravitational case in the appropriate limits, and extend numerical work by previous authors.