Search

Up to 17 GPa, the crystalline phases of N2 are characterized by pronounced orientational disorder, whereas the higher-pressure phases of molecular N2 are ordered. This raises the question about long-term relaxation of orientational disorder within the low- to intermediate-pressure regime. Here, this question is addressed by comparing synthetic with natural, chemically pure, solid N2 that resides as inclusions in diamonds at 300 K for about 108 years at pressures up to 11 GPa. It is shown that disorder prevails at 8.7 GPa, 300 K, where both synthetic and natural N2 assume the same structure. However, at 10.8 GPa, natural solid N2 exhibits monoclinic distortion and partial orientational ordering of the molecules, both of which are not observed in synthetic material. This difference is interpreted as the result of long-term structural relaxation. The ordering mechanism is examined and placed into the context of the δ- to ε-N2 transition. We present explanations for the absence of complete ordering of δ-N2. [ABSTRACT FROM AUTHOR]

Many elite athletes find the loss of their athletic abilities due to age or injury to be a profoundly challenging experience. While talent development is a well-studied phenomenon, far less attention has been paid to the issue of talent loss. We address this gap by exploring the experience and challenges faced by elite athletes who are losing, or who have lost, their talent. Drawing on three different understandings of the nature of talent, we argue that the experience of talent loss is constituted by three distinct yet interrelated forms of disorientation. We conclude by examining how athletes and those supporting them may respond to these challenges. [ABSTRACT FROM AUTHOR]

In this study, we investigated the creation of mono crystalline diamond membranes for use in two-dimensional optical cavities. The creation method involves ion irradiation to create a buried layer of damaged material that is removed to leave a free-standing mono crystalline top layer. Simulations were used to determine the optimal parameters for irradiation, which were tested in experiments. Hydrogen ions were found to be the optimal ion species for irradiation, and long-term high-temperature annealing was beneficial in reducing ion-induced damage in the membrane. The resulting membranes, which were 300 nm thick, contained a high density of negatively charged nitrogen-vacancy centers. Their optical and spin properties were analyzed. The findings of this study can be applied to the creation of diamond membranes hosting other color centers, with thicknesses matched to their respective fluorescence. [ABSTRACT FROM AUTHOR]

The static electric dipole–dipole coupling between donor–acceptor pairs (DAPs) in wide-bandgap semiconductors has recently emerged as a means of realizing a quantum science platform through optically controllable, long-range interactions between defects in the solid state. In this work, we generalize DAPs to consider arbitrary dopant populations and demonstrate that the charge of the NV center in diamond is well suited for quantum science. Explicitly, we leverage experimental results [see Z. Yuan et al., PRR 2, 033263 (2020)] to show that shallow NV centers can be efficiently initialized to a given relative population of the negative and neutral charge states and that modulating the surface termination would allow for control of the timescale over which the initialization and subsequent computations would occur. Furthermore, we argue that the observation of electroluminescence from the neutral charge state of the NV center [see N. Mizuochi et al., Nat. Photon. 6, 299 (2012)], but not from the negative charge state, implies the ability to interface with the NV center's charge in a manner analogous to the spin interface enabled by the spin-state dependent fluorescence of the NV center. [ABSTRACT FROM AUTHOR]

A precise description of the thermodynamic states of gaseous and solid detonation products is essential when using thermodynamic calculations to determine the detonation performance and destructive power of explosives. For high oxygen-lean explosives (the oxygen contained in explosives is insufficient to completely oxidize combustible elements and excess solid carbon will be generated in the detonation products), the phase state of solid carbon product affects the Chapman–Jouguet (CJ) detonation performance parameters, reaction zone, and energy release process. However, the recovery of detonation products demonstrates that the actual detonation carbon product is primarily a mixed state of diamond/graphite stack, as opposed to the existing thermodynamic codes, which essentially treat detonation carbon as single-phase carbon. To understand the thermodynamic effect of the mixed carbon phase state on the non-ideal detonation behavior, in this work, the matching relationship among the VINET equation of state parameters, thermodynamic potential parameters of the solid products of the equivalent system and the phase mixed system was constructed by using the nonlinear fitting method. The relationship between the carbon phase composition at the CJ point and the explosive composition structure was researched. Investigations were conducted into how the mixed carbon phase affected the volume and content of gas products as well as the composition at CJ points. Diamond formation in products is good for enhancing explosive's working capacity. Based on mixed-state potential parameters, the correlation mechanism between the mixed carbon phase and the chemical reaction zone was investigated, and it was found that intramolecular carbon/intermolecular carbon and more detonation graphite/diamond products all would lead to the extension of the reaction zone. [ABSTRACT FROM AUTHOR]

Density functional theory was employed to examine the adsorption and thermal evolution of nitrogen species on diamond(111) impacted by microwave N2 plasma. On bare domains of diamond, as represented by the models of C(111)-2 × 1 and graphite-like C(111), N2(ad) is identified as the major surface species; the desorption of N2(ad) proceeds on both models via a concerted process of breaking two C–N bonds. By contrast, there is evidence of the formation of (NH)2(ad) via the insertion reaction of microwave N2 plasma on hydrogenated domains of diamond, as represented by the models of C(111)-2 × 1-H and C(111)-1 × 1-H. Interestingly, contrasting dynamics of desorption of (NH)2(ad) are presented on these two models, that is, via sequential breaking of two C–N bonds on C(111)-2 × 1-H and via concerted breaking of both C–N bonds on C(111)-1 × 1-H. Our results demonstrate that the observed diversity of surface nitrogen species in composition, bonding, vibration, and desorption in prior experiments is linked to domains of a variety of surface terminations and reconstructions on diamond(111). [ABSTRACT FROM AUTHOR]

The authors implanted P atoms at 50 and 140-keV energies with respective fluences of 1 × 10 14 and 2 × 10 14 /cm 2 into diamond thin films synthesized by chemical vapor deposition on the type-Ib diamond substrate formed by high-pressure and high-temperature conditions. The occupational sites of implanted P atoms were determined in each processing stage of P implantation, ion-beam-induced epitaxial crystallization (IBIEC) annealing by 3-MeV-Ne 2 + ion irradiation at 750 ° C, and thermal annealing at 850 ° C in vacuum, by quantitatively comparing the random and channeling yields in Rutherford backscattering (RBS) measurements. In the analysis of RBS spectra, simulated distributions were fitted to the experimentally obtained spectra and we quantitatively identified the occupational sites and ratio of implanted P atoms. In addition, we investigated the diffusion phenomenon of implanted P atoms during annealing processes from the depth profile of scattered He ions. Consequently, the averaged occupational ratio in the substitutional lattice site was stably recorded around 50%. From the depth profile in the RBS spectra, thermal diffusion of implanted P atoms was clearly observed during the last thermal annealing after MeV-IBIEC annealing. We finally discuss the potentials of the MeV-IBIEC irradiation at relatively low temperatures applying to useful and credible annealing methods for electrical activation as well as recovery of damaged crystallinity. [ABSTRACT FROM AUTHOR]

In this work, nitrogen vacancy (NV) centers of high nitrogen diamond implanted with arsenic ions were investigated by photoluminescence spectroscopy. The transition of the NV center charge state was discussed by the regularly changing laser excitation power and measurement temperature following high-temperature annealing. After high-temperature annealing, the amorphous layer generated by arsenic ion implantation is transformed into a graphitization layer, resulting in a decrease in the NV yield. The electric neutral NV (NV0) center and negatively charged NV (NV−) center are affected by both radiation recombination and Auger recombination with increasing laser power. Accompanied by the increasing measurement temperature, the intensities of NV centers gradually decreased and eventually quenched. In addition, the charge states of NV− and NV0 centers were undergoing a transition. The zero phonon line positions of NV centers were also red shift, it was attributed to the dominant role of electron–phonon interaction in the temperature-dependent displacement of diamond energy gaps. The full width at half maxima of NV center were broadened significantly at higher temperatures. [ABSTRACT FROM AUTHOR]

Due to fascinating physical properties powered by remarkable progress in chemical vapor deposition of high-quality epilayers, diamond thin films attract great attention for fabrication of nitrogen-vacancy-based solid-state spin systems capable of operating in ambient conditions. To date, diamond heteroepitaxy via bias-enhanced nucleation is an unavoidable method for reliable wafer-scale film manufacturing. In this work, we analyze the coalescence phenomena in nitrogen doped, heteroepitaxial diamond epilayers, with a particular focus on their specific role in the annihilation of macroscopic crystal irregularities such as grain boundaries, non-oriented grains, and twinned segments. Here, we also report on the growth mechanism for the "primary" crystal orientation along with a predominant formation of two different types of boundaries highlighting the {011}-type as a main source of the crystal lattice irregularities. [ABSTRACT FROM AUTHOR]

In this work, we demonstrate a hydrogen-terminated diamond (H-diamond) field-effect transistor (FET) with Al2O3/CeB6 gate materials. The CeB6 and Al2O3 films have been deposited by electron beam evaporation technique, sequentially. For the 4/8/12/15 μm gate length (LG) devices, the whole devices demonstrate distinct p-type normally off characteristics, and all the threshold voltage are negative; all the absolute values of leakage current density are 10−4 A/cm2 at a VGS of −11 V, exhibiting a relatively low leakage current density compared with CeB6 FETs, and this further demonstrates the feasibility of the introduction of Al2O3 to reduce the leakage current density; the maximum drain–source current density is −114.6, −96.0, −80.9, and −73.7 mA/mm, which may be benefited from the well-protected channel. For the 12 μm LG devices, the saturation carrier mobility is 593.6 cm2/V s, demonstrating a good channel transport characteristic. This work may provide a promising strategy for the application of normally off H-diamond FETs significantly. [ABSTRACT FROM AUTHOR]

Mn-doped diamond (111) layers were grown by microwave plasma chemical vapor deposition using bis(methylcyclopentadienyl)manganese as a Mn source. The Mn concentration ([Mn]) was intentionally controlled in the range between ∼1 × 1015 and ∼1 × 1017 cm−3 by regulating the Mn/C molar ratio in the gas phase within 0.15%–3.0%. When [Mn] > ∼1 × 1016 cm−3, the step edges of the growing surface changed from straight to a zigzag shape. Using a model based on the classic theory by Cabrera and Vermilyea, we show that this roughening of the step edges resulted from step pinning due to Mn atoms absorbed on the diamond surfaces. [ABSTRACT FROM AUTHOR]

We deduce equations to calculate coupling coefficients of diamond micro-ring resonators. The equations can be used universally at any wavelength but not limited to the transmission peaks/valleys, and can be adapted with triangular cross-sections and tapered waveguides. Consequently, we build three models in accordance to different diamond processing technologies. These models deal with ring resonators with either rectangular cross sections, or triangular cross sections, or with tapered bus for triangular cross sections. The calculated coupling coefficients can be well fitted by exponential decay functions of gap d. Due to geometrical limitations, triangular-cross-sectional diamond resonators are shown to have much smaller (factor 20) coupling coefficients than those of rectangular-cross-sectional resonators. A tapered bus is shown to be beneficial to increase the coupling coefficient. Besides the calculation of coupling coefficients, the method presented in the paper can also be used to calculate the bending loss of micro-ring resonators, as a complement to the existing methods. [ABSTRACT FROM AUTHOR]

This paper reports the energies and charge and spin distributions of the low-lying excited states in singlet and triplet N2V defects in diamond from direct Δ-SCF calculations based on Gaussian orbitals within the B3LYP, PBE0, and HSE06 functionals. They assign the observed absorption at 2.463 eV, first reported by Davies et al. [Proc. R. Soc. London 351, 245 (1976)], to the excitation of a N(sp3) lone-pair electron in the singlet and triplet states, respectively, with estimates of ∼1.1 eV for that of the unpaired electrons, C(sp3). In both cases, the excited states are predicted to be highly local and strongly excitonic with 81% of the C(sp3) and 87% of the N(sp3) excited charges localized at the three C atoms nearest neighbor (nn) to the excitation sites. Also reported are the higher excited gap states of both the N lone pair and C unpaired electron. Calculated excitation energies of the bonding sp3 hybrids of the C atoms nn to the four inner atoms are close to that of the bulk, which indicates that the N2V defect is largely a local defect. The present results are in broad agreement with those reported by Udvarhelyi et al. [Phys. Rev. B 96, 155211 (2017)] from plane wave HSE06 calculations, notably for the N lone pair excitation energy, for which both predict an energy of ∼2.7 eV but with a difference of ∼0.5 eV for the excitation of the unpaired electron. [ABSTRACT FROM AUTHOR]

The incorporation of boron into a diamond lattice holds the potential to advance X-ray optics, offering the capability to manipulate various parameters of the lattice. This includes enhancing near-infrared absorption relative to pure diamond, thereby enabling Q-switchable optics. The use of MeV boron implantation emerges as a promising method for precisely doping the diamond lattice. However, for these optics to function effectively as Bragg-reflecting mirrors, ion implantation must be executed with meticulous attention to maintaining a strain-free, perfect diamond lattice. This study aimed to investigate the feasibility of utilizing a 9 MeV ion beam for high energy boron implantation. Different areas of a high-pressure, high-temperature (HPHT) diamond sample were subjected to irradiation with 9 MeV Boron ions, ranging in fluences from 5×1015 to 2.5×1016ions/cm2. Following boron implantation, high-temperature vacuum annealing was performed to restore the diamond lattice. Our assessment utilized X-ray rocking curve imaging, surface profilometry, and micro-Raman spectroscopy, with additional observations on near-infrared transmission properties. Our measurement of high-quality Bragg reflection through X-ray rocking curve imaging, sensitive to implantation-induced strain and defects, served as an key diagnostic for the effectiveness of this ion-implanted sample as a Bragg-reflecting optic.

We report on sub-terahertz plasmonic wave generation in the 2DEG channel of diamond TeraFET when biased by a DC current at the drain. Our numerical results demonstrated that p-diamond can support resonant oscillation of 300 GHz at room temperature, allowing it to function as a sub-THz emitter. We investigated the impact of different channel lengths, gate biases, drift velocities, and temperatures on the fundamental mode oscillation. The model incorporated the decay factors owing to electron scattering and electron fluid viscosity. [ABSTRACT FROM AUTHOR]

The advancement of the intelligent manufacturing industry (IMI) represents the future direction for the world's manufacturing sector, offering a promising avenue to bolster national competitiveness and enhance industrial manufacturing efficiency. In this study, we took the industrial robot industry (IRI) as a case study to elucidate the spatial distribution and interconnections of IMI from a geographical perspective, and the modified diamond model (DM) was used to analyze the influencing factors. Results show that: 1) the spatial pattern of IRI with various investment attributes in different industrial chain links is generally similar, centered in the southeast. Key investment areas are in the east and south. The spatial distribution of China's IRI covers a multitude of provinces and obtains different scales of investment in different countries (regions). 2) The spatial correlation between foreign investors and China's provincial-level administrative regions (PARs) forms a network, and the network of foreign-invested enterprises is more stable. Different countries (regions) have distinct location preferences in China, with significant spatial differences in correlation degrees. 3) Overall, the interaction of these factors shapes the location decisions and correlation patterns of industrial robot enterprises. This study not only contributes to our theoretical knowledge of the industrial spatial structure and industrial economy but also offers valuable references and suggestions for national IMI planning and relevant industry investors. [ABSTRACT FROM AUTHOR]

The ∼ 1.15-billion-year-old (Ga) Premier kimberlite pipe (Cullinan diamond mine), South Africa, is composed of several distinct kimberlite facies (Grey, Brown, Pale Piebald, Dark Piebald, Black Coherent [Type 3C], Blue/Brown Transitional, and Fawn). We report bulk rock Re-Os isotope data for Premier kimberlite facies, as well as for a suite of entrained peridotite and mafic xenoliths. These data are complemented by bulk rock highly siderophile element (HSE: Re, Pd, Pt, Ru, Ir, Os), major- and trace-element abundances. Measured 187Os/188Os for the kimberlite facies range from 0.1223 to 0.1672 (γOs i of −2.5 to + 17.4), peridotite xenoliths range from 0.1096 to 0.1244 (γOs i of −13.3 to −1.1), and pyroxenite xenoliths range from 0.1796 to 0.938 (γOs i of + 27 to + 419). A single measured amphibolite xenolith has the most radiogenic measured 187Os/188Os of 2.86 (γOs i of + 43). Harzburgite xenoliths yield time of rhenium depletion model ages (T RD) of ∼ 1.5 to 2.8 Ga, consistent with average T RD ages for Premier peridotites (2.4 ± 0.4 Ga). With these and published data, we considered the relationships between kimberlite and mantle xenoliths, compare estimates of relative peridotite incorporation to sampled diamond grade, and explore recratonization versus refertilization arguments with regards to T RD model ages. Kimberlite melt infiltration into Premier peridotite xenoliths is evident from melt veins accounting for ∼ 2 and ∼ 14 modal % of samples, and has led to incompatible element enrichment, including elevated Re. In turn, kimberlites show geochemical evidence for addition of peridotite xenolith fragments, with Type 3C having > 30 % more peridotite contribution than the Brown volcaniclastic facies. Kimberlites and peridotites plot on a 187Re/188Os versus 187Os/188Os mixing line (R2 = 0.92), with kimberlites having older apparent ages than the true age of crystallization. This mixing line provides estimates of lithospheric incorporation into the kimberlites, where the units with higher peridotite incorporation do not correlate with diamond grade. This is likely due to lithological and post-emplacement alteration heterogeneity within the kimberlite units, perhaps also reflecting the eclogitic paragenesis of many Premier diamonds. The peridotites provide evidence for the nature of the lithosphere beneath Premier prior to ∼ 1.15 Ga. Metasomatism of the peridotites is possibly linked to the Bushveld Igneous Event at ∼ 2 Ga, as well as to other magmatic events that affected the Kaapvaal craton from the Archean to the Mesoproterozoic. Premier peridotites do not suggest that the cratonic lithosphere beneath the region was completely replaced. Samples with Proterozoic T RD eruption model ages may represent Archean lithosphere that experienced alteration by metasomatism and modification, such as during the Bushveld Igneous Event. [ABSTRACT FROM AUTHOR]

A novel integral identity is introduced that can be applied to circular and diamond symmetric functions. It is demonstrated how this new identity and its alternative representations can be employed to facilitate integral derivations, including available examples in the literature as its special cases. As another application of the presented integral identities, a new integral transform is introduced that transforms circular symmetric functions to corresponding diamond symmetric functions. It is also illustrated how other integral equalities can be developed based on the introduced identities and using known integral transform kernels. Then, two-dimensional Mellin and Fourier transform kernels are adopted as case studies. [ABSTRACT FROM AUTHOR]

In 2002, the site of a shipwreck in Cardigan Bay, west Wales, thought to be the final resting place of the fully rigged ship Diamond, was designated by Cadw under the Protection of Wrecks Act 1973. Subsequent investigations into the remains of the vessel on the seabed by the Malvern Archaeological Diving Unit, together with comparisons made against documented historical research relating to Diamond, led to the conclusion that the identity of the ship on this underwater site was almost certainly mistaken. This deduction is, however, not the end of the matter, as while it answered the long-standing question relating to the validity of the name Diamond being ascribed to this shipwreck, it neither threw any light upon the actual identification of the vessel on the site, or the possible location and final resting place of Diamond. This article is an attempt to answer both these two pertinent and outstanding questions. [ABSTRACT FROM AUTHOR]

In this article, we define a generalization of the domino shuffling algorithm for tilings of the Aztec diamond to the interacting k-tilings recently introduced by S. Corteel, A. Gitlin, and the first author. We describe the algorithm both in terms of dynamics on a system of colored particles and as operations on the dominos themselves. [ABSTRACT FROM AUTHOR]

Photonic crystals built with 3D diamond structures have potentially large bandgaps, which can benefit a wide range of applications, such as daytime radiative cooling, where emissivity needs to be targeted at certain wavelengths in the infrared. However, building simple and low-cost 3D diamond-lattice photonic crystals remains a challenge. In this work, we develop a new processing technique to fabricate a 3D diamond-lattice photonic crystal based on a ⟨ 110 ⟩ surface-terminated structure to ease the creation of a deep lattice structure through reactive ion etching through the surface. This fabrication results in a significant amount of broadband selectivity, characterized by relatively high reflection in the visible wavelength range, as well as low reflection and high emissivity in the mid- to long-wavelength infrared range. Simulations performed in the Stanford Stratified Structure Solver indicate a reasonable agreement with experimental measurements, while suggesting approaches for further improvement. [ABSTRACT FROM AUTHOR]

Flat band (FB) systems, featuring dispersionless energy bands, have garnered significant interest due to their compact localized states (CLSs). However, a detailed account on how local impurities affect the physical properties of overlapping CLSs is still missing. Here we study a diamond chain with a finite magnetic flux per plaquette that exhibits a gapped midspectrum FB with non-orthogonal CLSs, and develop a framework for projecting operators onto such non-orthogonal bases. This framework is applied to the case of an open diamond chain with small local impurities in the midchain plaquette, and analytical expressions are derived for FB states influenced by these impurities. For equal impurities in top and bottom sites under diagonal disorder, we show how the impurity states experience an averaged disorder dependent on their spatial extension, leading to enhanced robustness against disorder. For a single impurity, an exotic topological phase with a half-integer winding number is discovered, which is linked to a single in-gap edge state under open boundary conditions. Numerical simulations validate the analytical predictions. Flat bands states can be written, in general, as localized states that can couple by placing impurities at the overlapping regions, when present. The authors develop an analytic framework to derive impurity states in a diamond chain with magnetic flux and find an exotic behavior of these states characterized by a half-integer winding number. [ABSTRACT FROM AUTHOR]

The drilling of State-of-the-Art printed circuit boards (PCBs) often leads to shortened tool lifetime and low drilling accuracy due to improved strength of the PCB composites with nanofillers and higher thickness-to-hole diameter ratio. Diamond coatings have been employed to improve the tool lifetime and drilling accuracy, but the coated microdrills are brittle and suffer from coating delamination. To date, it is still difficult to deposit diamonds on ultrathin microdrills with diameters lower than 0.2 mm. To avoid tool failure, the pretreatment was optimized to afford sufficient fracture strength and enough removal of cobalt. Further, the adhesion of the diamond coating was improved by employing an interlayer comprising SiC/microcrystalline diamond, which mitigates stress accumulation at the interface. By these means, microdrills with diameters of 0.8 and 0.125 mm were coated with adherent diamonds. In this context, the composite coating with the diamond/SiC interlayer and a nanodiamond top layer featured enhanced adhesion compared to single nano- or microdiamond coatings on the WC-Co microdrills. The composite diamond-coated WC-Co microdrills featured improved wear resistance, resistance to delamination of the diamond coating, and improved performance for drilling PCBs compared to micro- and nanodiamond-coated microdrills without interlayer. In addition, a higher hole quality was achieved when the diamond-coated microdrills were used. These results signify that the composite/nanodiamond coating features the highest bonding strength and best drilling performance. [ABSTRACT FROM AUTHOR]

We use P t and C t to denote a path and a cycle on t vertices, respectively. A diamond is a graph obtained from two triangles that share exactly one edge. A kite is a graph that consists of a diamond and another vertex adjacent to a vertex of degree 2 of the diamond. A gem is a graph that consists of a P 4 plus a vertex adjacent to all vertices of the P 4. Choudum et al. (2021) proved that every ( P 7 , C 7 , C 4 , gem)-free graph has either a clique cutset or a vertex whose neighbors is the union of two cliques unless it is a clique blowup of the Petersen graph, and every non-Petersen ( P 7 , C 7 , C 4 , diamond)-free graph has either a clique cutset or has a vertex of degree at most max { 2 , ω (G) − 1 }. In this paper, we extend these two results respectively to ( P 7 , C 4 , gem)-free graphs and ( P 7 , C 4 , diamond)-free graphs. We also prove that if G is a ( P 7 , C 4 , kite)-free graph with δ (G) ≤ ω (G) and without clique cutsets, then there is an integer ℓ ≥ 0 such that G = K ℓ + H , where H is either the Petersen graph or a well-defined graph F. This implies a polynomial algorithm which can determine the chromatic number of ( P 7 , C 4 , diamond)-free graphs, color ( P 7 , C 4 , kite)-free graphs G with (ω (G) + 1) colors, and color ( P 7 , C 4 , gem)-free graphs G with (2 ω (G) − 1) colors. [ABSTRACT FROM AUTHOR]

The unique spin-optical properties of NV defects in SiC, coupled with silicon carbide's advanced technology compared to diamond, make them a promising candidate for quantum technology applications. In this study, using photoinduced pulse ESR at 94 GHz (3.4 T), we reveal the room temperature spin coherence of NV defects in 6H-28SiC, purified to reduce 29Si concentration to ≈1%, four times below its natural level. We demonstrate room temperature (300 K) Hahn-echo coherence time T 2 = 23.6 μs, spin–lattice relaxation time T 1 = 0.1 ms, and coherent control over optically polarized NV spin states through Rabi nutation experiments. We reveal long inhomogeneous dephasing time T 2 * = 1.5 μs, which is about five times greater than that measured for NV defects in SiC with natural isotopic content. Our observations highlight again the potential of NV defects in 6H-28SiC, which exhibit near-infrared optical excitation and emission properties compatible with O-band fiber optics, as promising candidates for applications in quantum sensing, communication, and computation. [ABSTRACT FROM AUTHOR]

The nitrogen-vacancy center in diamond is an attractive resource for the generation of remote entangled states owing to its optically addressable and long-lived electronic spin. However, its low native fraction of coherent photon emission, ~3%, undermines the achievable spin-photon entanglement rates. Here, we couple a nitrogen-vacancy center with a narrow extrinsically-broadened linewidth (159 MHz), hosted in a micron-thin membrane, to an open microcavity. The resulting Purcell factor of ~1.8 increases the zero-phonon line fraction to over 44%. Operation in the Purcell regime, together with an efficient collection of the zero-phonon-line photons, allows resonance fluorescence to be detected for the first time without any temporal filtering. We achieve a >10 signal-to-laser background ratio. This selective enhancement of the center's zero-phonon transitions could increase spin-spin entanglement success probabilities beyond an order of magnitude compared to state-of-the-art implementations, and enable powerful quantum optics techniques such as wave-packet shaping or all-optical spin manipulation. [ABSTRACT FROM AUTHOR]

Optically detectable magnetic resonance spectra were measured for ensembles of NV-centers in CVD diamonds with different 13C contents. The obtained spectra were described using a model based on the spin Hamiltonian. The magnitude of the magnetic field applied to the sample was estimated using the constructed model and experimental data. [ABSTRACT FROM AUTHOR]

We revisit the definition of the temperature of a causal diamond for the case of a free massless scalar field. The stress is given to the intrinsic, direction-dependent character of this definition. Some important limits are also discussed. [ABSTRACT FROM AUTHOR]

To investigate the influence of special nanopore shapes on the mechanical properties of graphene at the atomic scale, a suitable nonlinear atomic-scale finite element model (AFEM) is developed based on the Stillinger Weber interatomic potential (SW). The discrete element created is an atomic finite element consisting of ten atoms, which can capture the dominant local and non-local atomistic interactions dictated by the present interatomic potential. Furthermore, the anterior works demonstrated the simplicity and the accuracy of the SW potential compared to the well-known interatomic potentials used in AFEM for predicting the elastic and fracture properties of graphene. The accuracy of the present model is checked by studying the graphene mechanical properties under the tensile and the shear tests, the comparison between our results and those reported in the literature showed a better agreement. The effect of diamond, hexagonal and rectangular nanopores, as well as their orientations on the elastic and fracture properties of graphene under the tensile and shear tests is also studied. Notably, previous literature lacks a comprehensive study on the shear properties of graphene under nanopore shapes. Our results show that the graphene's mechanical properties are more affected by the nanopores oriented perpendicular to the direction of the applied load. Particularly, the nanopores with elongated sharp tip edges, such as the diamond shape, have the greatest impact on graphene's mechanical response. The results show the ability of the present AFEM to investigate the mechanical behavior of graphene in the presence of various nanopore shapes with high precision at reduced computational time compared to its counterparts. Additionally, it offers simplicity and efficiency in studying large-scale systems. [ABSTRACT FROM AUTHOR]

To study the physicochemical (including adsorption) properties of nanodiamond, it is necessary to reproducibly obtain a carbon surface of an individual particle without metallic impurities of an unknown composition. Such a surface can be obtained through an additional procedure of the deep purification of a commercially available sample. This work is devoted to a study of the composition of non-combustible impurities of detonation diamond nanopowder. Using inductively coupled plasma mass spectrometry, iron and titanium are identified as the main metallic components of the non-combustible residue, the presence of Cr, Ni, Zr, As, and Sb is qualitatively established. The expected composition of the main molecular ions formed on the surface of the non-combustible residue under laser desorption/ionization mass spectrometry conditions is presented. Based on the results of the mass spectrometric analysis, a version of two-stage chemical treatment of detonation diamond nanopowder is proposed, which made it possible to reduce the mass fraction of non-combustible impurities during annealing in air from 2.0 to 0.1%. [ABSTRACT FROM AUTHOR]

Let S V (z) be a class of Schrödinger-Virasoro type Lie algebras, where z ∈ Z . In this paper, we show that S V (z) is 2-local complete (namely, every 2-local derivation is a derivation) for almost all integers z's. We also introduce the notion of full diamond thin Lie algebras, and construct an example F from S V (− 1) . We completely determine the derivations of F by combinatoric techniques, and show that F is not 2-local complete. [ABSTRACT FROM AUTHOR]

The TMS Board of Directors recently approved professional membership for a diverse group of new members from countries like the United States, Pakistan, Canada, and Zimbabwe, representing institutions ranging from universities to technology companies. This decision underscores TMS's commitment to inclusivity and collaboration within the minerals, metals, and materials science field. The list of new members welcomed in May and August 2024 includes individuals from various countries and institutions, showcasing a global community of researchers and professionals working together in fields like materials science and engineering. The document highlights international collaboration and knowledge exchange among researchers and professionals from countries such as the United States, Japan, Germany, and South Korea, emphasizing the importance of global partnerships in advancing scientific research efforts. [Extracted from the article]

We discuss the direct fabrication of embedded, graphitized features within high-purity, synthetic single-crystal diamond through ultrafast laser micromachining for the purpose of developing diamond-based capacitive structures. As an incorporating substrate, carbon in the form of highly pure synthetic diamond offers numerous advantageous physicochemical properties, including hardness, durability, optical transparency, and extremely high electrical resistance. On the other hand, graphitic carbon can exhibit exceptionally low electrical resistance. A simple sandwich structure of a thin sheet of diamond between two sheets of graphite could, therefore, form a simple plate-type capacitive structure. For a single structure consisting of 1 μm thick plates with areal dimensions of 5 × 1 mm2 and 1 μm gaps between plates, we estimate a capacitance of 240 pF, with a 3 kV/μm breakdown voltage in diamond. ∼2500 plates thus fabricated in a ∼5 × 5 × 1 mm3 diamond chip could, therefore, store ∼300 mJ of energy. To realize this kind of structure, we employ ultrafast laser micromachining with high numerical aperture focusing and precise positioning control to disrupt the crystalline matrix of a well-confined volume within single-crystal synthetic diamond, forming embedded graphitic features. Graphitized plate regions 1 μm thick with 1 μm separations can be fabricated in this manner, and empirical I–V measurements indicate resistances in the plates as low as ∼kΩ. We also address challenges involved with fabricating closely parallel, embedded graphitic plates in thick diamond substrates, including aberration, machining time, and cracking. [ABSTRACT FROM AUTHOR]

The detection of abrasive grain images in diamond tools serves as the foundation for assessing the overall condition of the tools, encompassing crucial aspects of diamond abrasive grains like the quantity, size, morphology, and distribution. Given the intricate background textures and reflective characteristics exhibited by diamond images, diamond detection and segmentation pose a significant challenge. Recently, numerous defect detection methods based on machine learning and deep learning have emerged. However, several issues persist, such as detection accuracy and the interference caused by intricate background textures. The present work demonstrates an efficient classification and segmentation network algorithm that combines Swin-Unet with SAM (Segment Anything Model) to alleviate the existing problems. Specifically, four embedding structures were devised to bridge the two models for iterative training. The transformer blocks within the Swin-Unet model were enhanced to facilitate classification and coarse segmentation, and the mask structure in SAM was refined to enable fine segmentation. The experimental results show that under a small sample dataset with complex background textures, the average index values of ACC (accuracy), SE (Sensitivity), and DSC (Dice Similarity Coefficient) for the classification and segmentation of diamond abrasive grains reached 98.7%, 92.5%, and 85.9%, respectively. Compared with the model before improvement, its ACC, SE and DSC increased by 1.2%, 15.9%, and 7.6%, respectively. The test results, based on four different datasets, consistently indicated that this model has excellent segmentation performance and robustness and has great application potential in the industrial field. [ABSTRACT FROM AUTHOR]

Large-volume presses (LVPs) providing large volumes, liquid media, deformation capability, jump compression, and in situ measurements are in great demand for high-pressure research, particularly in the fields of geoscience, condensed matter physics, material science, chemistry, and biology. A high-pressure and high-temperature (HPHT) platform with different LVP subsystems, both solid-state and liquid environments, and nonequilibrium subsystems, has been constructed at the Synergetic Extreme Condition User Facility, Jilin University. This article describes the construction of the different subsystems and provides an overview of the capabilities and characteristics of the different HPHT subsystems. A large sample volume (1000 mm3) at 20 GPa is achieved through the use of a belt-type apparatus in the solid-state subsystem. HPHT conditions (1.8 GPa and 1000 K) are realized in the liquid subsystem through the use of a piston–cylinder-type LVP with optical diamond windows for in situ spectroscopic measurements. A maximum pressure jump to 10.2 GPa can be reached within 20 ms in the nonequilibrium subsystem with the use of an improved bladder-pressurization jump press. Some typical results obtained with different LVPs are briefly reviewed to illustrate the applications and advantages of these presses. In summary, the platform described here has the potential to contribute greatly to high-pressure research and to innovations in high-pressure technology. [ABSTRACT FROM AUTHOR]

All-dielectric metasurfaces offer a low-loss alternative to plasmonic metasurfaces. We proposed the configuration for high-reflectivity all-dielectric metasurfaces based on single-crystal diamond (SCD) resonators on fused silica substrate and conducted simulations to optimize and analyze such a configuration via the FDTD solver. We utilized GMR as the design principle to select the configuration and the substrate material, and analyzed the scattering properties of a single SCD resonator by multipole decomposition. Then, we demonstrated that both the cylindrical resonators in square lattice and frustum-shaped resonators in hexagonal lattice can achieve near-unity reflectivity (>99.99%) and ultra-low absorption (<0.001%) at 795 nm, the typical alkali-metal laser wavelength. Additionally, we demonstrated that such a design is quite tolerant of fabrication errors and further supports its potential for realistic applications. To expand the functionality of such devices across multiple wavelengths, dual-band high-reflectivity metasurfaces at 744 nm and 828 nm were also designed. Our work is quite useful for designing diamond-based highly reflective mirrors, paving the way for low-loss all-dielectric reflective metasurfaces in high-power laser applications. [ABSTRACT FROM AUTHOR]

For each surface besides the sphere, projective plane, and Klein bottle, we construct a face‐simple minimal quadrangulation, that is, a simple quadrangulation on the fewest number of vertices possible, whose dual is also a simple graph. Our result answers a question of Liu, Ellingham, and Ye while providing a simpler proof of their main result. The inductive construction is based on an earlier idea for finding near‐quadrangular embeddings of the complete graphs using the diamond sum operation. [ABSTRACT FROM AUTHOR]

We report experimental studies of microsphere-enhanced fluorescence collection of nitrogen vacancy (NV) centers using silica microspheres with diameters ranging between 15 and 50 μm and employing 20× and 40× objectives with numerical aperture of 0.42 and 0.64, respectively. Photoluminescence-excitation saturation counts as high as 95 kHz have been observed. These studies show that due to the effective collimation of fluorescence by the microsphere, objectives with relatively low numerical aperture (NA) can be used without sacrificing collection enhancement, in agreement with a theoretical model based on Mie scattering. The large enhancement of fluorescence collection with relatively low NA objectives, which feature extralong working distance and are relatively inexpensive, can potentially enable wider use of NV-based quantum sensing in real world applications. [ABSTRACT FROM AUTHOR]

Free radical generation plays a key role in many biological processes including cell communication, maturation, and aging. In addition, free radical generation is usually elevated in cells under stress as is the case for many different pathological conditions. In liver tissue, cells produce radicals when exposed to toxic substances but also, for instance, in cancer, alcoholic liver disease and liver cirrhosis. However, free radicals are small, short-lived, and occur in low abundance making them challenging to detect and especially to time resolve, leading to a lack of nanoscale information. Recently, our group has demonstrated that diamond-based quantum sensing offers a solution to measure free radical generation in single living cells. The method is based on defects in diamonds, the so-called nitrogen-vacancy centers, which change their optical properties based on their magnetic surrounding. As a result, this technique reveals magnetic resonance signals by optical means offering high sensitivity. However, compared to cells, there are several challenges that we resolved here: Tissues are more fragile, have a higher background fluorescence, have less particle uptake, and do not adhere to microscopy slides. Here, we overcame those challenges and adapted the method to perform measurements in living tissues. More specifically, we used precision-cut liver slices and were able to detect free radical generation during a stress response to ethanol, as well as the reduction in the radical load after adding an antioxidant. [ABSTRACT FROM AUTHOR]

Single‐nitrogen‐vacancy (NV) centers in diamond are highly promising quantum nuclear magnetic resonance (NMR) sensors. However, their exposure to many sources of noise, such as surface impurities, shot noise from avalanche photodiode overlaps, and spin‐state projection errors inherent in quantum systems, limits their usefulness. Often, long measurement durations are required to accumulate sufficient data for NMR signal detection via fast Fourier transform spectrometry. For practical reasons, methods to shorten the necessary accumulation time for NMR signal detection are greatly desired. In this article, an on‐line formulation of maximum likelihood estimation (MLE) signal processing for quantum heterodyne NMR measurements is presented as a step toward this goal. This MLE method reduces the required data accumulation time by orders of magnitude and provides good estimates of target frequency locales in real time. These results are significant to practitioners of NMR detection with single‐NV centers in diamond who require a quick litmus test for potential signals when probing a wide area. [ABSTRACT FROM AUTHOR]

Overcoming the hardness‐toughness trade‐off in diamonds attracts much interest in physics, chemistry, materials science, and engineering. Recently synthesized nanotwinned diamond composite exhibits massive enhancement in fracture toughness without sacrificing its unprecedented Vickers hardness [Y. Yue et al., Nature 582, 370 (2020)]. Several mechanisms for the toughness enhancement are unveiled based on the edge‐cracked models while the mechanism from Vickers indentation has remained elusive. Here, the energy of nanotwinned diamonds, diamond polytypes, and diamond composites is systematically investigated from Vickers indentation simulation. The results show diamond structures dissipate energy by interface migration, accompanied by the phase transformation from diamond polytypes to the cubic diamond (3C diamond). By tuning the density and distribution of interfaces, the dissipated energy of the diamond is increased to more than twice that of a single‐crystal 3C diamond. This work complements the established mechanisms and provides a universal strategy for toughening diamonds and related materials. [ABSTRACT FROM AUTHOR]

An understanding of the structural changes induced by the ovalization treatment of diamonds is necessary to produce crystals with controlled sizes and morphologies. In this investigation, the treatment of natural diamonds in a rotary vortex apparatus was used to modify the surface morphology of the particles and obtain the ovalized crystals. The size of the starting diamond crystals was in the 250–350 μm range. In the product of treatment in the rotary vortex apparatus, particles with sizes above 300 μm were ovalized, while those with sizes below 300 μm demonstrated irregular shape. The formation of particles of irregular shape during the treatment was caused by the fracture of the starting diamond crystals along the defect regions. The ovalized crystals were formed by "blunting" the edges and vertices of the starting crystals under the action of friction forces. The ovalized diamond consisted of a crystalline core and a defect shell. The crystals were subjected to oxidative etching to reveal the structural changes of the surface layers caused by the ovalization treatment. During oxidative etching, the ovalized crystals developed a system of etch pits over the entire surface. In contrast, the oxidative etching of the starting (untreated) diamonds showed the facet selectivity. [ABSTRACT FROM AUTHOR]

This work report the generation of high‐order Laguerre–Gaussian (LG) modes from a nanosecond, optical vortex pumped diamond Raman laser. This system is capable of generating first‐Stokes (λ1st = 1240 nm) LG modes with topological charge (ℓ) of up to 26 and second‐Stokes (λ2nd = 1485 nm) LG modes with topological charge of up to 22, when pumped using a first‐order vortex beam. The maximum first‐ and second‐Stokes LG mode energies are measured to be 0.5 and 1 mJ, respectively, when pumping with energy of 19.8 mJ. [ABSTRACT FROM AUTHOR]

High‐pressure crystallographic data can be measured using a diamond anvil cell (DAC), which allows the sample to be viewed only along a cell vector which runs perpendicular to the diamond anvils. Although centring a sample perpendicular to this direction is straightforward, methods for centring along this direction often rely on sample focusing, measurements of the direct beam or short data collections followed by refinement of the crystal offsets. These methods may be inaccurate, difficult to apply or slow. Described here is a method based on precise measurement of the offset in this direction using a confocal optical device, whereby the cell centre is located at the mid‐point of two measurements of the distance between a light source and the external faces of the diamond anvils viewed along the forward and reverse directions of the cell vector. It is shown that the method enables a DAC to be centred to within a few micrometres reproducibly and quickly. [ABSTRACT FROM AUTHOR]

In 1967, Grünbaum conjectured that any d-dimensional polytope with d + s ⩽ 2 d vertices has at least ϕ k (d + s , d) = d + 1 k + 1 + d k + 1 - d + 1 - s k + 1 k-faces. This conjecture along with the characterization of equality cases was recently proved by the author (A proof of Grünbaum's lower bound conjecture for general polytopes. Israel J. Math. 245(2), 991–1000 (2021)). In this paper, several extensions of this result are established. Specifically, it is proved that lattices with the diamond property (e.g., abstract polytopes) and d + s ⩽ 2 d atoms have at least ϕ k (d + s , d) elements of rank k + 1 . Furthermore, in the case of face lattices of strongly regular CW complexes representing normal pseudomanifolds with up to 2d vertices, a characterization of equality cases is given. Finally, sharp lower bounds on the number of k-faces of strongly regular CW complexes representing normal pseudomanifolds with 2 d + 1 vertices are obtained. These bounds are given by the face numbers of certain polytopes with 2 d + 1 vertices. [ABSTRACT FROM AUTHOR]

The tree‐independence number tree‐α, first defined and studied by Dallard, Milanič, and Štorgel, is a variant of treewidth tailored to solving the maximum independent set problem. Over a series of papers, Abrishami et al. developed the so‐called central bag method to study induced obstructions to bounded treewidth. Among others, they showed that, in a certain superclass C of (even hole, diamond, pyramid)‐free graphs, treewidth is bounded by a function of the clique number. In this paper, we relax the bounded clique number assumption, and show that C has bounded tree‐α. Via existing results, this yields a polynomial‐time algorithm for the Maximum Weight Independent Set problem in this class. Our result also corroborates, for this class of graphs, a conjecture of Dallard, Milanič, and Štorgel that in a hereditary graph class, tree‐α is bounded if and only if the treewidth is bounded by a function of the clique number. [ABSTRACT FROM AUTHOR]

RBSC with a low residual Si less than 5 vol% was fabricated using SiC–C preform with diamond as a main carbon source by a conventional reaction sintering process at the temperature range between 1500 °C and 1800 °C. The diamond content in the SiC–C preform varied from 10 wt% to 17 wt%. The diamond as the main carbon source used in SiC–C preform effectively minimized the residual Si in RBSC by increasing the reaction of diamond due to the enhanced Si melt infiltration even in SiC–C preform with high carbon content. The Si melt infiltration should be performed above 1600 °C for the complete reaction of diamond particles with size of 0.5 μm because of the relatively low dissolution rate of diamond in Si melt. The flexural strength of RBSC with residual Si content less than 7 vol% exceeded 400 MPa. The flexural strength of RBSC was increased with decreasing residual Si content, but sharply decreased by the residual carbon accompanying pores in RBSC. RBSC with low residual Si content displayed moderate flexural strengths around 200 MPa even above Si melt temperature because of the formation of continuous SiC structure in RBSC by the enhanced grain growth of SiC. Vickers hardness of RBSC was steadily increased from 17.7 GPa to 24.6 GPa with decreasing residual Si. [ABSTRACT FROM AUTHOR]

Copyright of Journal of China University of Petroleum is the property of China University of Petroleum and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Current Research in Dental Sciences is the property of Ataturk University Coordinatorship of Scientific Journals and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)