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Detailed characterization of deep-level color centers requires understanding their electronic and atomic structure, which is most commonly investigated utilizing the Kohn–Sham density functional theory. Standard semilocal functionals based on the generalized gradient approximation (GGA) are inclined toward an imprecise quantitative description of defects' electronic structure. Hybrid functionals provide an improved prediction of electronic properties, albeit at a much higher computational cost. In this work, we test the newly developed Strongly Constrained and Appropriately Normed (SCAN) family of meta-GGA density functionals for selected color centers in diamond. In particular, we study nitrogen-, silicon-, germanium-, and tin-vacancy centers that have been recently investigated for their use in quantum technological applications. We show that SCAN and its derivatives, the rSCAN and r2SCAN functionals, significantly improve the calculated energies of optical transitions within the delta-self-consistent-field approach, almost reaching the accuracy of the hybrid Heyd–Scuseria–Ernzerhof (HSE) functional. In the case of the NV− center, we also show that the SCAN family of functionals improves the description of the adiabatic potential energy surfaces compared to both GGA and hybrid functionals, improving calculated luminescence lineshapes. As a result of these findings, we recommend using the SCAN family of functionals as a promising alternative for studying color centers in solids. [ABSTRACT FROM AUTHOR]

The silicon vacancy (SiV) center in diamond is drawing much attention due to its optical and spin properties, attractive for quantum information processing and sensing. Comparatively little is known, however, about the dynamics governing SiV charge state interconversion mainly due to challenges associated with generating, stabilizing, and characterizing all possible charge states, particularly at room temperature. Here, multi‐color confocal microscopy and density functional theory are used to examine photo‐induced SiV recombination — from neutral, to single‐, to double‐negatively charged — over a broad spectral window in chemical‐vapor‐deposition (CVD) diamond under ambient conditions. For the SiV0 to SiV‐ transition, a linear growth of the photo‐recombination rate with laser power at all observed wavelengths is found, a hallmark of single photon dynamics. Laser excitation of SiV‒, on the other hand, yields only fractional recombination into SiV2‒, a finding that is interpreted in terms of a photo‐activated electron tunneling process from proximal nitrogen atoms. [ABSTRACT FROM AUTHOR]

This study introduces a method for reconstructing vector microwave magnetic fields using a single nitrogen-vacancy (NV) center in locally strong effective fields with two different orientations in diamond, without the previously required external magnetic field. Due to the varying orientations of the effective fields, NV centers exhibit two distinct sets of switchable ground states. The resonant Rabi oscillations of an NV center in these two distinct states were utilized to reconstruct vector microwave magnetic fields. Remarkably, this technique achieves an angular resolution of 0.02 mrad / Hz . Overcoming the limitations inherent in previous practices of using NV ensembles, this breakthrough has the potential to substantially enhance both the spatial resolution and the sensitivity of microwave magnetic field imaging, a meaningful development for various scientific and technological applications. [ABSTRACT FROM AUTHOR]

Single-color centers in thin polycrystalline diamond membranes allow the platform to be used in integrated quantum photonics, hybrid quantum systems, and other complex functional materials. While single-crystal diamond membranes are still technologically challenging to fabricate as they cannot be grown on a non-diamond substrate, free-standing polycrystalline diamond membranes can be conveniently fabricated at large-scale from nanocrystalline diamond seeds on a substrate that can be selectively etched. However, their practical application for quantum photonics is so far limited by crystallographic defects, impurities, graphitic grain boundaries, small grain sizes, scattering loss, and strain. In this paper, we report on a single-photon source based on silicon-vacancy color centers in a polycrystalline diamond membrane. We discuss the spectroscopic approach and quantify the photon statistics, obtaining a g2(0) ≈ 0.04. Our findings hold promise for introducing polycrystalline diamond to quantum photonics and hybrid quantum systems. [ABSTRACT FROM AUTHOR]

Group IV vacancy color centers in diamond are promising spin-photon interfaces with strong potential for applications in photonic quantum technologies. Reliable methods for controlling and stabilizing their charge state are urgently needed for scaling to multiqubit devices. Here, we manipulate the charge state of silicon vacancy (SiV) ensembles by combining luminescence and photocurrent spectroscopy. We controllably convert the charge state between the optically active SiV- and dark SiV2- with megahertz rates and >90% contrast by judiciously choosing the local potential applied to in-plane surface electrodes and the laser excitation wavelength. We observe intense SiV- photoluminescence under hole capture, measure the intrinsic conversion time from the dark SiV2- to the bright SiV- to be 36.4(67) ms, and demonstrate how it can be enhanced by a factor of 105 via optical pumping. Moreover, we obtain previously unknown information on the defects that contribute to photoconductivity, indicating the presence of substitutional nitrogen and divacancies. [ABSTRACT FROM AUTHOR]

Quantum magnetometry based on optically detected magnetic resonance (ODMR) of nitrogen vacancy centers in diamond nano or microcrystals is a promising technology for sensitive, integrated magnetic-field sensors. Currently, this technology is still cost-intensive and mainly found in research. Here we propose one of the smallest fully integrated quantum sensors to date based on nitrogen vacancy (NV) centers in diamond microcrystals. It is an extremely cost-effective device that integrates a pump light source, photodiode, microwave antenna, filtering and fluorescence detection. Thus, the sensor offers an all-electric interface without the need to adjust or connect optical components. A sensitivity of 28.32 nT / Hz and a theoretical shot noise limited sensitivity of 2.87 nT / Hz is reached. Since only generally available parts were used, the sensor can be easily produced in a small series. The form factor of (6.9 × 3.9 × 15.9) mm 3 combined with the integration level is the smallest fully integrated NV-based sensor proposed so far. With a power consumption of around 0.1 W , this sensor becomes interesting for a wide range of stationary and handheld systems. This development paves the way for the wide usage of quantum magnetometers in non-laboratory environments and technical applications. [ABSTRACT FROM AUTHOR]

The high‐pressure and high‐temperature (HPHT) diamonds with well‐controlled defects and low stress offer an ideal host substrate for the fields of quantum information science; however, fabrication of quantum‐grade HPHT diamonds remains a pressing challenge. Here, a major advance in generating highly coherent nitrogen‐vacancy (NV) centers, a promising spin defect in diamonds, via tailored HPHT synthesis and postgrown annealing treatment is reported. The resulting well‐dispersed single NV− centers in type‐IIa diamonds exhibit long spin coherence times comparable to that of the reported chemical vapor deposition diamonds. Moreover, high‐density NV− ensembles in 〈100〉‐grown type‐Ib diamonds with superb zero‐phonon lines considerably sharper than those of native NV− centers in as‐grown diamonds, together with low splitting of resonances are produced. These findings demonstrate a superior synthesis and optimization protocol for creating high‐quality NV− centers avoiding lattice damage in diamond to meet the stringent requirements for a wide range of emerging quantum technologies. [ABSTRACT FROM AUTHOR]

Quantum diamond sensors of multiple physical quantities, especially magnetic field and temperature, have great application prospects in materials science, biophysics, and engineering. Here, we demonstrate joint quantum sensing of vector magnetic field and temperature based on ensembles of nitrogen-vacancy (NV) centers in the diamond. Combining the intrinsic C 3 ν symmetry of diamond crystals and multiple-frequency excitation technique, we can directly measure frequency-modulated optically detected magnetic resonance (ODMR) spectra for three different NV orientations and then obtain the Zeeman splittings and the center frequency movement of the electron spin. An artificially generated underlying external magnetic field is used to eliminate degeneracy and facilitate coordinate transformations. The six-channel phase-locked amplification technology enables simultaneous detection of vector magnetic field and temperature with a sensitivity of about 0.87 nT/Hz1/2 and 0.32 mK/Hz1/2; meanwhile, a 23 dB isolation between magnetic and temperature signals is kept. This technology realizes the simultaneous measurement of arbitrary vector magnetic field and temperature, which can be used to study the temperature-varying magnetic phase transition. [ABSTRACT FROM AUTHOR]

We study an s-wave superconductivity in a one-dimensional dimerized diamond lattice in the presence of spin–orbit coupling and Zeeman field. The considered diamond lattice, comprising of three sublattices per unitcell and having flat band, has two dimerization patterns; the intra unitcell hoppings have the same (opposite) dimerization pattern as the corresponding inter unitcell hoppings, namely, neighboring (facing) dimerization. Using the mean-field theory, we calculate the superconducting order parameter self-consistently and examine the stability of the superconducting phase against the spin–orbit coupling, Zeeman splitting, dimerization, and temperature. We find that the spin–orbit coupling or Zeeman splitting individually has a detrimental effect on the superconductivity, mostly for the facing dimerization. But their mutual effect revives the superconductivity at charge neutrality point for the facing dimerization. [ABSTRACT FROM AUTHOR]

We study an s-wave superconductivity in a one-dimensional dimerized diamond lattice in the presence of spin–orbit coupling and Zeeman field. The considered diamond lattice, comprising of three sublattices per unitcell and having flat band, has two dimerization patterns; the intra unitcell hoppings have the same (opposite) dimerization pattern as the corresponding inter unitcell hoppings, namely, neighboring (facing) dimerization. Using the mean-field theory, we calculate the superconducting order parameter self-consistently and examine the stability of the superconducting phase against the spin–orbit coupling, Zeeman splitting, dimerization, and temperature. We find that the spin–orbit coupling or Zeeman splitting individually has a detrimental effect on the superconductivity, mostly for the facing dimerization. But their mutual effect revives the superconductivity at charge neutrality point for the facing dimerization. [ABSTRACT FROM AUTHOR]

The optical properties of point luminescent centers formed in the volume IaA-type natural diamond under the action of ultrashort laser pulses in the visible range (515 nm) with durations of 0.3–2.4 ps were investigated. The analysis using confocal Raman spectroscopy demonstrates the formation of nitrogen vacancy centers (NV) and there are no graphitization traces in processing areas. The luminescence amplitude of NV centers depends linearly on the exposure time at different durations of ultrashort laser pulses. [ABSTRACT FROM AUTHOR]

The nitrogen-vacancy (NV) centers in diamond have the ability to sense alternating-current (AC) magnetic fields with high spatial resolution. However, the frequency range of AC sensing protocols based on dynamical decoupling (DD) sequences has not been thoroughly explored experimentally. In this work, we aimed to determine the sensitivity of the ac magnetic field as a function of frequency using the sequential readout method. The upper limit at high frequency is clearly determined by Rabi frequency, in line with the expected effect of finite DD-pulse width. In contrast, the lower frequency limit is primarily governed by the duration of optical repolarization rather than the decoherence time (T 2 ) of NV spins. This becomes particularly crucial when the repetition (dwell) time of the sequential readout is fixed to maintain the acquisition bandwidth. The equation we provide successfully describes the tendency in the frequency dependence. In addition, at the near-optimal frequency of 1 MHz, we reached a maximum sensitivity of 229 pT/ Hz  by employing the XY4-(4) DD sequence. [ABSTRACT FROM AUTHOR]

The results of the development of a two-frequency resonator operating at frequencies of 4.95 and 7.1 MHz, which correspond to the frequencies of hyperfine transitions of the ground state of a nitrogen-vacancy color center in diamond, are presented. The efficiency of the resonator has been demonstrated via observation of Rabi oscillations. With a resonator input power of 0.3 W, the amplitude of the alternating magnetic field was 1.6 and 1 mT for field frequencies of 4.95 and 7.1 MHz, respectively. [ABSTRACT FROM AUTHOR]

This document is a journal article titled "A Near-Colourless HPHT-grown Diamond with Natural-appearing Blue Fluorescence from N3 Centres." The article discusses the discovery of a near-colorless synthetic diamond with blue fluorescence that closely resembles the fluorescence of natural diamonds. The diamond was grown using a high-temperature, high-pressure (HPHT) process and exhibited characteristics typically associated with boron-doped HPHT-grown diamonds. However, further analysis revealed that the blue fluorescence was due to the presence of N3 centers, which are typically found in natural diamonds. The article concludes that while near-colorless synthetic diamonds with blue fluorescence can pose an identification challenge, a combined approach including observations of growth zoning and photoluminescence spectroscopy can positively identify them. [Extracted from the article]

The outstanding electronic properties of graphene make this material a candidate for many applications, for instance, ultra-fast transistors. However, self-heating and especially the detrimental influence of available supporting substrates have impeded progress in this field. In this study, we fabricate graphene-diamond heterostructures by transferring graphene to an ultra-pure single-crystalline diamond substrate. Hall-effect measurements were conducted at 80 to 300 K on graphene Hall bars to investigate the charge transport properties in these devices. Enhanced hole mobility of 2750 cm2 V−1 s−1 could be observed at room-temperature when using diamond with reduced nitrogen ( N s 0 ) impurity concentration. In addition, by electrostatically varying the carrier concentration, an upper limit for mobility is determined in the devices. The results are promising for enabling carbon–carbon (C-C) devices for room-temperature applications. [ABSTRACT FROM AUTHOR]

Nitrogen-vacancy (NV) centers in diamond as ideally individual spin quantum systems can be coherently manipulated by microwave fields. Compared to the traditional method using the IQ (In-phase/Quadrature) mixer with a local oscillator and intermediate-frequency (IF) signals, we report an effective and technically simple method to generate the required microwave field by frequency multiplication and realize coherent manipulation of the NV center's electron spin. After frequency multiplication, the IF signal can be directly converted to the high-frequency microwave field with adjustable pulse width, frequency, phase, and amplitude. A series of spin dynamics applications such as Rabi oscillation, free induction decay, and spin-locking are executed, which verified its performance and feasibility. Frequency multiplication can overcome the problem of clock synchronization between the local oscillator and IF signal and greatly reduce the complexity of the experimental system. The method can be easily used to realize a more complex quantum control sequence such as dynamic decoupling and extended to a wide range of spin-based quantum information applications in the future. [ABSTRACT FROM AUTHOR]

Recently, there has been much interest in using Group IV elements from the periodic table to fabricate and study X V color centers in diamond, where X = Si , Ge, Sn, or Pb and V is a carbon vacancy. These Group IV color centers have a number of interesting spin and optical properties, which could potentially make them better candidates than N V − centers for important applications in quantum computing and quantum information processing. Unfortunately, the very same ion implantation process that is required to create these X V color centers in diamond necessarily also produces many carbon vacancies (V C ), which can form complexes with these color centers (V C − X V) that can dramatically affect the properties of the isolated X V color centers. The main focus of this work is to use density-functional theory to study the thermodynamics and kinetics of the formation of these V C − X V complexes and to suggest experimental ways to impede this process such as varying the Fermi level of the host diamond material through chemical doping or applying an external electrical bias. We also include a discussion of how the simple presence of many V C can negatively impact the spin coherence times (T 2) of Group IV color centers through the presence of acoustic phonons. [ABSTRACT FROM AUTHOR]

A microwave plasma reactor for diamond growth that allows for highly controllable process conditions is presented. The position of the diamond substrate within the reactor can be accurately controlled. Thus, equilibration of plasma conditions can be carried out after changes in process parameters. With this approach, sharp layer transitions among doped, undoped, and isotopically controlled diamond films can be obtained. In addition to the sample transfer, the growth temperature is maintained through a substrate heater, and a clean reactor environment is realized by a load‐lock sample exchange system. The plasma conditions are constantly monitored by optical emission spectroscopy. Using this system, the growth of nanoscopic sandwich structures is demonstrated with controlled isotopic ratios down to ≈10 nm thickness and N(V) layers below 50 nm are obtained on (001)‐oriented diamond. Growth rates and doping efficiencies depending on the used methane concentration are presented. Characterization with continuous‐wave optically detected magnetic resonance yields an average contrast of 4.1% per nitrogen vacancy (NV) orientation in layers with a thickness below 100 nm. Depending on the used methane concentration, surface morphology and NV doping homogeneity are influenced as observed by photoluminescence and atomic force microscopy measurements. [ABSTRACT FROM AUTHOR]

Here, we study the two-periodic weighted dimer model on the Aztec diamond graph. In the thermodynamic limit when the size of the graph goes to infinity while weights are fixed, the model develops a limit shape with frozen regions near corners, a flat "diamond" in the center with a noncritical (ordered) phase, and a disordered phase separating this diamond and the frozen phase. We show that in the mesoscopic scaling limit, when weights scale in the thermodynamic limit such that the size of the "flat diamond" is of the same order as the correlation length inside the diamond, fluctuations of the height function are described by a new process. We compute asymptotics of the inverse Kasteleyn matrix for vertices in a local neighborhood in this mesoscopic limit. [ABSTRACT FROM AUTHOR]

We present a new magnetometry method integrating an ensemble of nitrogen-vacancy (NV) centers in a single-crystal diamond with an extended dynamic range for monitoring a fast changing magnetic-field. The NV-center spin resonance frequency is tracked using a closed-loop frequency locked technique with fast frequency hopping to achieve a 10 kHz measurement bandwidth, thus allowing for the detection of fast changing magnetic signals up to 0.723 T/s. This technique exhibits an extended dynamic range subjected to the working bandwidth of the microwave source. This extended dynamic range can reach up to 4.3 mT, which is 86 times broader than the intrinsic dynamic range. The essential components for NV spin control and signal processing, such as signal generation, microwave frequency control, data processing, and readout, are integrated in a board-level system. With this platform, we demonstrate a broadband magnetometry with an optimized sensitivity of 4.2 nT Hz−1/2. This magnetometry method has the potential to be implemented in a multichannel frequency locked vector magnetometer suitable for a wide range of practical applications, such as magnetocardiography and high-precision current sensors. [ABSTRACT FROM AUTHOR]

Lean Six Sigma (LSS) is a rigorous, data-driven, and results-oriented process improvement philosophy. To date, there is no evidence of a study of the application of LSS in a diamond plant. One of the most common recovery methods in the diamond industry has been dense medium separation (DMS), also known as heavy medium separation (HMS). The main purpose of the study is to investigate how to implement LSS to improve the dense medium separation performance at a diamond plant. Further, we investigate the factors impacting DMS by finding the most relevant factor/s and applying the principles of Lean and Six Sigma to improve the performance of dense medium separation (DMS) at a diamond plant in Namibia. The research found out that factors affecting DMS include cyclone pressure, medium density, viscosity, and worn cyclone parts and maintaining these parameters within narrow limits in relation to the correct set points is beneficial. Also, the study established that, operational conditions (cyclone pressures and medium densities) are the topmost factors affecting DMS followed by viscosity and lastly, equipment dimensions. The application of LSS reduced downtime delays and boosted the associated production, thus achieving cost-efficiency, improved DMS performance and reducing waste. Diamond mines are found in large numbers in Africa, and this study will help the mines to improve their efficiency. Further, using the lens of theory of swift and even flow, the LSS is applied in the diamond company to streamline the DMS performance. Further, it poses key implications for future LSS research. [ABSTRACT FROM AUTHOR]

The interest in application of nanodiamonds as nanotheranostics is increasing rapidly over recent years. The combination of properties, such as high refractive index, low toxicity, inertness, high carrier capacity and rich surface functionalities, as well as unique magneto-optical properties of the nitrogen-vacancy centre, renders fluorescent nanodiamonds superior to other nanomaterials as nanotheranostics. In this review, the current state of research on the applications of nanodiamonds as theranostics where they have been utilised in combination with both diagnostics/imaging and therapy simultaneously is discussed. Firstly, a brief introduction to the current knowledge about the synthesis and properties of nitrogen-vacancy centre in nanodiamonds is given. Then, the underlying principles that are responsible for the magneto-optical properties of nitrogen-vacancy centre are explained. The majority of theranostic applications of nanodiamonds rely on the judicious engineering of their surface with bioactive molecules. In the following section, methods of engineering the surface of nanodiamonds while preserving their colloidal stability and their implication on in vitro and in vivo biocompatibility are described. Subsequently, the recent developments and applications of nanodiamond conjugates as photo-theranostics and non-targeted and targeted theranostics are critically discussed. Co-delivery of specifically tailored nanodiamonds with both diagnostic/imaging and therapeutic features can considerably contribute towards nanotheranostics-based personalized medicine. [ABSTRACT FROM AUTHOR]

Vacancy-related color centers in diamonds, such as nitrogen-vacancy (NV) and silicon-vacancy (SiV) centers, have good application prospects in solid-state quantum technologies. In various applications, shot noise-limited sensitivity is determined by coherence time and photoluminescence (PL) intensity, which depends on the color center density. However, the conversion efficiencies of impurity atoms to color centers are low and usually increased by electron irradiation, which destroy the lattice structure and create defects leading to decoherence. In this study, we epitaxially grew diamond layers containing color centers on surfaces coated with metal stripes. The PL intensities of NV0, NV−, and SiV− centers located directly above the metal surface were 3.27, 3.47, and 11.15 times higher than those of the diamond epitaxial region. The [N]–[NV] and [Si]–[SiV] conversion efficiencies were 63.26% and 35.68%, respectively, which were comparable to or even better than those achieved by electron irradiation. Moreover, the region above the metal exhibited a high lattice quality, longer transverse relaxation time, higher magnetic field sensitivity, and larger NV−/NV0 ratio. The findings of this study can help advance the existing research on NV-based magnetometers, biofluorescent labeling, and interfacial spin quantum memory and be potentially applied to other vacancy-related color centers, such as germanium-vacancy. [Display omitted] • Diamond layers with color centers are grown on surfaces with periodic metal stripes. • The color centers above the metal surface exhibit high photoluminescence intensity. • The enhanced conversion efficiencies of impurity atom to color centers exceed those enhanced by ion implantation. • The spin coherence time, magnetic field sensitivity, and ratio of NV−/NV0 are also improved. [ABSTRACT FROM AUTHOR]

Retail sector continues to be the most blooming and powerful sector in India. In Indian economic system the contribution of the Retail quarter up to 10% of GDP is high-quality. A store is a service provider or an agent or a commercial enterprise corporation, whose major enterprise is promoting the goods and offerings immediately to customers thru various distribution channels the fame and fortune of the sector changed completely after the invasion of internet to the retail sector. Prior to the involvement of internet buying and selling was done physically through direct retailing but after the invasion of internet its E-commerce that's ruling the traditional retail sector in India. Online shopping is a part of e-trade which is accomplished commonly by way of the users due to e-commerce web sites in India which lets in us to purchase and promote the products according to our choice at less expensive charge. E-trade internet site has loads of impacts on extraordinary markets and shops. Many corporations began retail business thru website hosting their very own websites together with large form of products and services together with attractive offers to the customers. This platform works as a consortium which avails all the goods which can be available in petty shops to the big buying department shops. It incorporates apparels, shoes, plumbing substances, fixtures, jewelry and food gadgets and so forth. It allows the customers to buy the goods in keeping with their want in time without tons put off. As a result, as a result E-stores have emerged to fulfill the needs of massive segments of clients. On line shopping has experienced a rapid growth throughout the recent years due to its flexibility in operations. This study includes analysis about the benefits of online buying to the clients, Impact of increasing traits, challenges and threats faced by way of the fixed save stores. This paper puts up how E-commerce has changed the traditional retailing in India through the literature gathered from different experts and also suggest steps to improve traditional retailing in hand with E-commerce in India on due analysis. [ABSTRACT FROM AUTHOR]

Ceramic is an ideal material for preparing micro-channel catalyst supports with their characteristics of high temperature resistance, corrosion resistance and mechanical strength. High aspect ratio micro-channel structure has the advantages of large specific surface area, strong mass and heat transfer performance and high material utilization. However, ceramic materials are hard and brittle, and it is difficult to fabricate micro-channel structures with aspect ratio more than 1.5:1 by traditional processing methods. In this paper, a cutting method of large diameter diamond wire sawing was proposed. The micro-channels with width of 520 μm and aspect ratio of more than 4:1 was successfully fabricated by this method. Furthermore, the integrity of the micro-channel structure processed by diamond wire sawing was analyzed. And than the effect of surface morphology in different processing parameters on the catalyst loading performance were studied. The catalyst loading strength of ceramic slices with different surface morphology was tested. Finally, the ceramic micro-channel array was used as the catalyst support in micro-reactor for hydrogen production via methanol steam reforming (MSR). The methanol conversion rate and H 2 production rate could reach 87.8% and 74.6 mmol/h, respectively under GHSV 12600 ml/g·h at 300 °C. The experimental results show that the large-diameter diamond wire sawing technology can be used to process ceramic microchannels with high aspect ratio; using ceramic microchannel arrays as catalyst supports in hydrogen production can obtain better reaction performance; the feasibility of ceramic materials were broadened as microchannel catalyst supports. • The large diameter diamond wire sawing technique was proposed to fabricate high aspect ratio ceramic-based microchannel array. • Influences of surface morphology on catalyst loading performance were analyzed. • Ceramic-based microchannel array was used in methanol steam reforming reaction for hydrogen production and better performance was obtained. [ABSTRACT FROM AUTHOR]

The Cash in Transit (CIT) deals with the money distribution and picking up between depot(s), central bank, bank branches, Automated Teller Machines (ATMs), jewelry stores, and exchange offices, safely and quickly. It is critical for companies carrying out CIT activities to identify risks and their priorities. It is one of the problems to be resolved for CIT companies to determine the risks that may occur on the route for each vehicle that will carry money from a certain center to the demand points. It is important for decision makers how critical these routes are concerning risks. Within the scope of the study, determining the risks, the weights of these risks, and high-risk routes accordingly are discussed. The literature review related to the problem is first consulted. After the literature review, interviews are made with experts on their subject. The main criteria and sub-criteria to define the risks are determined. Then, these criteria are weighted by the Interval-Valued Intuitionistic Fuzzy Analytical Hierarchy Process (IVIF-AHP), and risk assessment is made to alternative routes based on these weighted risks. The routes are evaluated by Interval-Valued Intuitionistic Fuzzy Technique for Order Preference by Similarity to Ideal Solution (IVIF-TOPSIS) methodology, and thus, it is determined which route has the highest risk and which route has the lowest risk. In this way, it is stated on which route should be used for the vehicles to distribute money and which routes should be improved. [ABSTRACT FROM AUTHOR]

Magnesium-and germanium-vacancy centers were produced in diamond by ion implantation and the post-annealing process. Photoluminescence spectroscopy (PL) measurements were performed between 20 and 50 °C. The PL results of the GeV centers are in agreement with those found in the literature, while the MgV center is newly discovered and a not yet broadly investigated color center, but the room temperature PL results are in agreement with the first report. The temperature dependence of the MgV centers above room temperature is unusual: by increasing the temperature, its PL shifts to higher energies, contrary to what is observed for the GeV centers and other known centers in the literature. The zero phonon line width of both centers broadens by increasing the temperature in both investigated centers. The origin of the blue shift observed in the MgV centers as a confinement effect is discarded, because sample is bulk and its origin should lay on the influence of the temperature on the local static structure and the overlapping of the electronic wave functions. Our results show the ability of MgV to be used in future for thermometry. The center is bright and photostable, with a narrow full width at half maximum compared to other centers in diamond and its shift with the temperature is also larger. [ABSTRACT FROM AUTHOR]

[Display omitted] • Using the low-density crystal seeding method, diamond particles containing silicon color centers were prepared on a single-crystal silicon substrate. • Controlled preparation of arrayed diamond nanopillars was achieved by an anodized aluminum oxide template combined with a metal dewetting process. • The nanopillars, prepared with uniform diameter and regular arrangement, enhance the luminescent performance of diamond color centers. Diamond nanopillars can improve the photon emission efficiency of diamond color centers. In this study, a low-cost and controllable method for preparing array nanopillars, which is different from photolithography, is proposed. Single-crystal diamond particles containing silicon color centers were prepared by low-density crystal seeding method. Array metal masks of different sizes were prepared on the surfaces of the diamond particles by controlling the metal film deposition time, passing through anodized aluminum oxide array holes, and cooperating with the metal film dewetting process. Subsequently, diamond array nanopillars of different sizes were prepared using oxygen plasma etching. The fluorescence detection indicates that the fluorescence intensity of silicon vacancy color centers in the nanopillar arrays is enhanced by 14.4 times compared to that inside diamond particles. The effects of the color center depth and nanopillar diameter on the excitation efficiency, Purcell factor, photon emittance, and total fluorescence efficiency of the color center in diamond array nanopillars were simulated by the finite-difference time-domain method. It was found that the total fluorescence efficiency of the color center could be up to 89 %, which was 20 times higher than that of the diamond bulk. This provides solutions for improving quantum communication, quantum detection efficiency, and low-cost device preparation. [ABSTRACT FROM AUTHOR]

This study investigates the enhancement of convective heat transfer in Triply Periodic Minimal Surfaces (TPMS), focusing on Gyroid and Diamond lattice structures. An innovative lattice structure control method, employing a Deform-Control parameter (β), is proposed to modulate lattice deformation within their mathematical frameworks. Numerical simulations validated by experimental measurements were conducted to analyze the impact of varying β values from 0 to 0.75 on the thermo-hydraulic performance of both lattice types at flow rates ranging from 0.4 m3/h to 2 m3/h. The results indicate significant improvements in heat transfer efficiency with increasing β. For Gyroid structures, increasing β from 0.1 to 0.75 led to a 3.8% to 32.7% rise in convective heat transfer coefficients and a 3.2% to 23.7% increase in Nusselt numbers. Diamond structures also demonstrated enhancements, with coefficients and Nusselt numbers climbing by 2.9% to 10.4% and 3% to 7%, respectively. Notably, both Gyroid and Diamond structures showed increase in flow resistance at higher β values, highlighting a critical balance between heat transfer efficiency and fluid flow considerations. This research presents a promising control method for optimizing heat transfer in TPMS structures, offering opportunities for more efficient and effective heat dissipation solutions. • A New Geometric Control Method for Gyroid and Diamond TPMS structures is introduced. • The key parameter " β " is manipulated to govern lattice deformation. • Optimization of " β " improves convective heat transfer in Gyroid and Diamond structures. • Gyroid structures' and Diamond deformation boosts heat transfer by 33% and 3.4%. • Deformed Gyroid and Diamond structures show up to 23.7% and 10.4% increase in Nu. [ABSTRACT FROM AUTHOR]

A model sectorial synthetic Ib-diamond plate with a minor concentration of substitutional atomic nitrogen C -centers was exposed in its bulk by tightly focused 0.2-ps, 525-nm laser pulses, coming at 80-MHz repetition rate and nJ-level variable pulse energies. Structural conversion into NV- and other carbon vacancy/interstitial-related centers was observed by infrared, optical and 3D confocal photoluminescence (PL) microspectroscopy, exhibiting in the optical range the ultra-broad (UV-near-IR) and smooth (structureless) absorption/photoluminescence spectra. PL intensity measured at the selected 480 and 530-nm wavelengths demonstrates its third power of the corresponding pulse energy dependences (∝E3) and avalanche-like dynamics as a function of laser exposure. Our analysis of electron-hole plasma photoexcitation and related generation of non-thermalized Auger carriers as a function of laser pulse energy (∝E1/2 and ∝E3/2, respectively) indicates that the known two-hole Auger-induced surface desorption mechanism could be anticipated in bulk diamond for interstitial-vacancy Frenkel pair generation, which rate could be evaluated via structural conversion rate for C -centers. At higher pulse energies tremendous interstitial-vacancy Frenkel pair generation rates could result not only in structural conversion of impurity-based color centers, but also in ultrafast "non-thermal" structural disordering in diamond. • New color centers based on carbon interstitials/vacancies were laser-inscribed in a diamond. • Complete conversion of substitutional nitrogen atoms occurred in dense electron-hole plasma. • Color-center photogeneration rate exhibits the third power of laser pulse intensity. • Interstitial-vacancy pair generation was related to two-hole localization mechanism. • Color-center photogeneration proceeds via avalanche-like process. [ABSTRACT FROM AUTHOR]

This retrospective study reports data obtained by the Federal Police's National Institute of Criminalistics (INC‐PF) relating to chemical analysis aimed at identifying explosives used in Automated teller machines (ATMs)/cash safes robberies between 2014 and 2020 in Brazil. 93 Real cases were studied and, based on the analysis carried out on the materials related to these cases, focusing on the type of explosive used, the following distribution profile was obtained: I) explosive mixtures based on chlorates and/or perchlorates (53%); explosive emulsion (22%); black gunpowder (13%); negative/inconclusive (11%) and organic ‐ pentaerythritol tetranitrate (PETN) (1%). These results can contribute to investigations related to diversion/loss of explosives for criminal purposes, indicating, for example, through relationships between prevalence in the use of a certain type of explosive with a certain location, its possible origin (mining industry, explosive industries, fireworks factories, among others). The profile observed in the results can guide the selection of explosives to be studied in future research, as the possibilities are vast. Furthermore, despite the expressive number of occurrences in Brazil in the period of interest of this study, only a small fraction of samples was sent to the forensic chemistry laboratory to identify the explosive involved, which suggests that expanding chemical analysis should be encouraged in this field. In combination with an increase in professional training and collaboration trials between the laboratories, these activities can improve the chemical explosive's profile in Brazil, enabling the search for correlations between occurrences and contributing to the growth and development of this area. [ABSTRACT FROM AUTHOR]

The negatively charged nitrogen-vacancy (NV−) center in diamond is a model quantum system for university teaching labs due to its room-temperature compatibility and cost-effective operation. Based on the low-cost experimental setup that we have developed and described for the coherent control of the electronic spin [Sewani et al., Am. J. Phys. 88, 1156–1169 (2020)], we introduce and explain here a number of more advanced experiments that probe the electron–nuclear interaction between the NV− electronic and the 14N and 13C nuclear spins. Optically detected magnetic resonance, Rabi oscillations, Ramsey fringe experiments, and Hahn echo sequences are implemented to demonstrate how the nuclear spins interact with the electron spins. Most experiments only require 15 min of measurement time and, therefore, can be completed within one teaching lab. [ABSTRACT FROM AUTHOR]

For quantum sensing, it is vital to develop an efficient technique for determining the quantum state of the sensor. We optimize the weighting of the photoluminescence intensity for readout of the spin state of the nitrogen-vacancy (NV) center in diamond. We find that adopting a physical model that considers the optical transitions and relaxations of the NV center allows for an efficient readout. Our method improves the signal-to-noise ratio of the readout by 5.4% in a short time of 3 s, while the existing methods typically require 1 min of integration time. We also show that our technique enhances the readout of the nuclear spin memory. The demonstrated way is helpful for a wide range of measurements, from a few minutes to several days. [ABSTRACT FROM AUTHOR]

The article discusses the testing of a cricket bat-shaped diamond, weighing 1.04 carat, for its natural origin and authenticity, featuring unique spectroscopic features and an inscription of Virat Kohli's name.

• A self-consistent multi-physics coupling model including microwave electromagnetic field, plasma field and fluid heat transfer field is established. • CH 4 -H 2 plasma characteristics from 18 to 100 W∙cm−3. • Kinetics of CH 4 -H 2 plasma chemical reaction at high average power density. • High-rate growth of high-quality Φ 60 mm diamond films at high average power density of 100 W∙cm−3. Investigating the mechanism behind the high-efficiency deposition of high-quality diamond has always been a prominent topic in related research. This paper investigates the CH 4 -H 2 plasma characteristics and related chemical reaction kinetics in the average power density range of 18–100 W·cm−3, which is a typical range for large-area diamond film deposition. The number densities of H, CH 3 and C 2 H 2 increase linearly with the average power density. C 2 H 2 is the main hydrocarbon in the discharge, and CH 3 is the main single-carbon hydrocarbon. The number density and radial uniformity of CH 3 and C 2 H 2 increase with the average power density, which is necessary for the high rate and uniform deposition of diamond films. The plasma's optical emission spectra indicate an acceleration in the C 2 production rate at high power density. The diamond film deposition experiment demonstrates the efficacy of high average power density in achieving high-quality diamond deposition at a high growth rate. [ABSTRACT FROM AUTHOR]

• The drain current and transconductance of hBN/GaN/diamond HEMT are increased by 47 % compared to SiO 2 /GaN/sapphire HEMT. • The effect of hBN passivation layer on GaN HEMT operation is investigated. • The lattice temperature is reduced from 507 K in SiO 2 /GaN/sapphire HEMT to 370 K in h-BN/GaN/diamond HEMT. • The thermal resistance R th is decreased by a factor of 5 upon transferring GaN HEMT to diamond substrate. • Self-heating effects are significantly minimized after transferring GaN HEMT to diamond substrate. In this article, we investigate through numerical simulation the reduction of self-heating effects (SHEs) in GaN HEMT via the integration of hexagonal boron nitride (h-BN) as a passivation layer and as a release layer to transfer GaN HEMT to diamond substrate. The obtained devices exhibit improved thermal performance compared to SiO 2 /GaN/sapphire HEMT. The lattice temperature was reduced from 507 K in SiO 2 /GaN/sapphire to 372 K in h-BN/GaN/diamond HEMT. The temperature decrease enhances the drain current and transconductance to 900 mA/mm and 250 mS/mm, corresponding to a 47 % improvement. In addition, the total thermal resistance R th is reduced by a factor of 5 from 27 K mm/ W in GaN/sapphire HEMT to 5.5 K mm/ W in GaN/diamond HEMT. This study indicates that h-BN integration in GaN HEMT as a top heat spreader and a release layer for transfer to diamond substrate can be a promising solution to reduce self-heating effects and extend the device lifetime and reliability. [ABSTRACT FROM AUTHOR]

A comprehensive and up-to-date compilation of observed and calculated hydrogen (H)-related peaks that occur in the near- and middle-infrared spectra of diamond is presented. The experimental database contains >300 observed peaks attributed to H-related impurities in natural diamond. The database of calculated peaks includes data from first-principles simulations of the FTIR spectra of different V x N y H z defects in diamond and contains >300 peaks that correspond to different C-H, N-H, and B-H vibrational modes for each V x N y H z defect. Less than ~10 % of observed H-related peaks have been assigned to specific defects. Consequently, the computational database was constructed to better understand the properties of different V x N y H z defects that may correspond to different observed peaks. In general, hydrogen-rich diamonds with a dominant Type Ib character and thus poorly aggregated N, show a larger number of low-intensity, H-related peaks compared to diamonds with a dominant Type Ia character. For example, ~51 % of observed H-related peaks are only observed in Type Ib diamonds, ~9 % of peaks are only observed in diamonds with a dominant Type Ia character and ~40 % of peaks are observed in both Type Ia and Type Ib diamonds. There is a major increase in the number of distinct H-related peaks in Type IaA + Ib diamonds compared to Type Ib diamonds suggesting N-aggregation processes responsible for the formation of A-centers may also produce many distinct V x N y H z defects capable of trapping H. There is a major decrease in the number of H-related peaks in Type IaA > Ib diamonds compared to Type IaA + Ib diamonds suggesting that many of the V x N y H z defects associated with the initial production of A-centers become unstable with increasing mantle residence time and the progressive loss of C-centers. These defects likely combine (or disaggregate and then re-combine) to form fewer, relatively more intense, H-related peaks observed in Type IaA > Ib diamonds. Many of these peaks persist through continued annealing in the mantle and are observed in Type IaA , IaAB , and IaB diamonds. Our data suggests that N and H incorporation are not correlated during diamond growth and that in the early stages of diamond residence, H is incorporated into many distinct V x N y H z defects that involve C- and A-centers. With continued residence and annealing, and the progressive formation A-centers and loss of C-centers, these defects aggregate to form relatively fewer, presumably more stable, V x N y H z defects such as VN 3 H. [Display omitted] • Only 10% of observed H-related IR peaks are assigned to specific defects. • VH 3 and VH 4 defects may not occur in natural diamond as H requires N to aggregate. • The VN 3 H defect may be produced by numerous distinct N/H-aggregation sequences. • H-rich Type Ib and IaA + Ib diamonds show a large number of H-related IR peaks. • H-related defects in Type Ia diamonds are relatively more stable during annealing. [ABSTRACT FROM AUTHOR]

The nitrogen-vacancy (NV) centers in diamond are promising applied in quantum sensing devices, and surface termination of diamond surface can be engineered to effectively modulate its electronic property, and then expand its application. In this work, the structures of N-terminated diamond (111) surface are searched based on swarm-intelligence structural method, and the electronic property is investigated by first-principles calculation. Two kinds of N-terminated diamond (111) surfaces have thermal and dynamical stabilities, positive electron affinity (2.59 and 2.50 eV), no surface related states in the band gap region, and no surface electron spins. We make further inspections by placing the NV center ~10 Å below the surface, and find that the surfaces have little effect on the defect states of NV center. Thus, N-terminated diamond (111) surfaces are promising candidates for NV based quantum sensors. [Display omitted] • Novelty N-terminated diamond (111) structures have been searched. • N termination has no obvious effects on the electronic property of NV center. • 1 ML-α, 1 ML-β structures are potential to apply in shallow NV centers. [ABSTRACT FROM AUTHOR]