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While nano-crystalline diamond (NCD) is a promising engineering composite material for its unique mechanical properties, achieving the ultrahigh surface quality of NCD-based components through conventional grinding and polishing is challenging due to its exceptional hardness and brittleness. In the present work, we experimentally investigate the nanosecond laser ablation-induced graphitization characteristics of NCD, which provides a critical pretreatment method of NCD for realizing its superlative surface finish. Specifically, systematic experimental investigations of the nanosecond pulsed laser ablation of NCD are carried out, in which the characteristics of graphitization are qualitatively characterized by the Raman spectroscopy detection of the ablated area of the microhole and microgroove. Subsequently, the influence of laser processing parameters on the degree and morphological characteristics of graphitization is evaluated based on experimental data and related interpretation, from which optimized parameters for maximizing the graphitization of NCD are then identified. The findings reported in the current work provide guidance for promoting the machinability of NCD via laser irradiation-induced surface modification. [ABSTRACT FROM AUTHOR]

This study delves into the intricate social dynamics of South Kalimantan's traditional diamond mines, revealing a potential for conflict amidst the promise of economic uplift. South Kalimantan is one of the provinces in Indonesia, known nationwide for its diamond production. Going beyond conventional economic and environmental perspectives, the research employs Galtung's Conflict Theory, examining the interplay of attitudes, behaviours, norms, values, and political influences. By adopting this nuanced approach, the study unveils hidden fault lines within these communities, providing a comprehensive understanding of how diverse factors converge to create discord. The consequences of unaddressed conflict include shattered livelihoods, environmental degradation, and fractured communities. The study employs rigorous quantitative methods to empower stakeholders in proactive conflict management, including questionnaires and Structural Equation Modeling (SEM) with data from 400 respondents. The findings underscore the significant roles of behaviours, attitudes, norms, and politics in fueling tension, with values demonstrating surprisingly less direct influence. This insight is a roadmap for conflict prevention and sustainable development, allowing stakeholders to tailor interventions based on specific conflict-driving factors. The study urges a shift from reactive to proactive measures, envisioning a future where prosperity continues and communities thrive in harmony, free from conflict. [ABSTRACT FROM AUTHOR]

In this contribution, we are interested in the prediction of the macroscopic thermal conductivity of three-phasic composite materials such as wood fibers. The main idea is to make use of up-scaling such as homogenization to link the pore scale and the sample scale. The studied wood species incorporates three phases: the air, the lumen or matrix and the fibers. Image processing is preformed on a tomographic acquisition with high resolution of some micrometers. It serves to identify the present phases and generates the morphology mesh. The 2D diamond scheme is employed to discretize Fourier's model posed on the segmented morphology. The resulting algorithm is validated using an exact solution. Optimal numerical convergence rates of second order are recorded. The thermal conductivity is therefore estimated following the 2D orthotropic directions. An emphasis is set on the impact of the orientation of fibers on this thermal property. [ABSTRACT FROM AUTHOR]

The article focuses on the growth and characteristics of laboratory-grown diamonds, with a detailed visit to Clarity Diamond's Chemical Vapor Deposition (CVD) facility in Austin, Texas. Topics include the chemical vapor deposition (CVD) diamond growth process, the unique properties and applications of polycrystalline CVD diamonds, and the education provided to retailers and consumers about these synthetic gems.

Over the past two decades, GIA has documented a rapid evolution of laboratory-grown diamonds; this article provides a comprehensive overview of these developments and summarizes novel laboratory-grown diamonds that may become more common in the future. The industry has seen a significant increase in the quantity, size, and quality of laboratory-grown diamonds, making them viable for commercialization on a larger scale. Nevertheless, there have been relatively few changes in laboratory-grown diamonds during the last five years, indicating that developments have largely stabilized for now. This overview summarizes the two diamond growth processes: high-pressure, high-temperature (HPHT) and chemical vapor deposition (CVD). It explores the major trends observed by GIA since 2007, the year it began issuing synthetic diamond grading reports. CVD products now dominate the supply of laboratory-grown diamonds submitted for grading reports, with the majority of these also undergoing post-growth HPHT treatment to remove their color. This article discusses methods and strategies for identifying laboratory-grown diamonds by providing their distinguishing gemological characteristics as well as results from recent developments in advanced testing approaches. [ABSTRACT FROM AUTHOR]

The paper considers the possibility of changing the morphology of inclusions in diamonds based on the study of these inclusions and the inclusion–diamond boundary. Raman spectroscopy and transmission electron microscopy methods were used. According to the literature data, it is known that the octahedral form of mineral inclusions in diamond is induced, and does not correspond to the initial conditions of joint growth of diamond and inclusion, but the mechanism of this process is not considered. Solids differ in the value of surface Gibbs energy; the harder the material, the higher its melting point and the greater the value of surface Gibbs energy In the case of the diamond–inclusion pair, the surface energy of diamond far exceeds the surface energy of the inclusion. Diamond crystals have a surface energy value for an octahedron face of 5.3 J/m2, dodecahedron—6.5 J/m2, and cube—9.2 J/m2, i.e. it is anomalously high compared to the surface tension of silicate and other minerals. Therefore, the mineral inclusion in diamond tends to the form corresponding to the minimum of free energy in the "diamond–inclusion" pair, and when the energy of diamond dominates, the final shape will be determined by it, i.e. it will be an octahedron. The authors suggest the possibility of redistribution of diamond substance around the inclusion with simultaneous change of the inclusion morphology. [ABSTRACT FROM AUTHOR]

Diamond is emerging as an attractive third‐generation wide‐bandgap semiconductor for future on‐chip nonlinear photonics and quantum optics due to its unique thermal, optical, and mechanical properties. However, the light‐driven current under below‐band gap excitation from the second‐order nonlinear optical effect in diamond is still challenging. Herein, a giant second‐order nonlinear photocurrent is observed in the chemical vapor deposition (CVD) diamond by utilizing terahertz (THz) emission spectroscopy. This ultrafast photocurrent originates from the photon drag effect (PDE), during which the momentum transfer from the incident photons to the charge carriers at the rich grain boundaries of the CVD diamond after the exclusive subgap π–π* transition upon femtosecond laser excitation. Especially, the interplay between circular and linear PDE to the THz generation is clarified and distinguished under elliptically polarized light excitation. Furthermore, the picosecond ultrafast dynamics of these charge carriers are also verified by infrared spectroscopy. Owing to the giant photon‐drag‐induced ultrafast photocurrent, the CVD diamond presents the highest THz emission efficiency compared with the reported carbon allotropes, which expands the new functionality of diamond nonlinear photonics into on‐chip THz devices. [ABSTRACT FROM AUTHOR]

Koh-i-Noor and other world-famous diamonds such as Hope, Orloff, Great Mogul, Nizam, and Pitt, well-known in the industry as 'Golkonda Diamonds' are very well recognised for their rare colours, large carat sizes, and because of the paucity of nitrogen atoms majority of them have been classified as Type IIa diamonds. These renowned Golkonda diamonds were recovered from placers mined on the banks of the Krishna River in southern India; however, their primary source rocks (either kimberlites or lamproites) remain questioned and untraced. Precise identification of the primary sources of such large-sized, dominantly Type IIa diamonds (i.e., CLIPPIRS) is crucial for understanding their deep mantle origin, nature and timing of magmatism carrying them and essential from economic and geological perspectives. We employed a multidisciplinary approach incorporating xenocrystic mineral composition and bulk-rock geochemistry, field geological and remote sensing (GIS) studies to locate the probable primary sources of these renowned diamonds, know the origin of Type IIa Golkonda diamonds in southern India, and to understand the mechanism and timing of diamond transport and dispersal as placers in the Krishna River basin. Our study rules out the possibility of various lamproite occurrences of the Eastern Dharwar Craton and Banganapalle conglomerates as being sources of Koh-i-Noor and other Golkonda diamonds. The absence of Type IIa diamonds in the highly diamondiferous Late Cretaceous kimberlites of Wajrakarur likewise excludes them as source of Golkonda diamonds. Among southern India's two significant kimberlite fields, i.e., Wajrakarur and Narayanpet, compositions of indicator minerals from the Wajrakarur Kimberlite Field (WKF) reveal their ultimate diamond preservation potential, presence of strong diamondiferous mantle roots and deeper source regions, hence recognising them to be the potential sources of Golkonda diamonds. GIS and remote sensing tools were used to calculate moisture content, vegetation indices, and to locate paleo-channel of the Penner River, which was primarily responsible for the transportation of diamonds from their Mesoproterozoic (ca. 1.1 Ga) source rocks at Wajrakarur to their final sites of recovery, i.e., Kolluru and other mines situated on the banks of the Krishna River. The occurrence of alluvial placer deposits in Krishna River drainage system is analogous to the Orange River drainage system in South Africa. Both areas have diamonds sourced from primary kimberlite pipes, transported by rivers, and deposited in specific areas. Similarities in the origin, mechanism of diamond transport, dispersal and deposition have played a crucial role in significant diamond production from alluvial deposits in Krishna and Orange Rivers. [ABSTRACT FROM AUTHOR]

Recent advances have shown the beneficial impact of adding nanoparticles to thermal oil. Diamond and boron nitride nanoparticles have superior thermal conductivity and excellent thermal and optical properties. In the current study, thermal conductivity, specific heat, and rheological behavior of diamond and boron nitride-based hybrid nanofluids in thermal oil are experimentally investigated for 0%, 0.2%, 0.4%, and 0.6% weight concentrations and a wide range of temperatures. The proportion between diamond and boron nitride utilized in the study is 1:1. A two-step method is applied to prepare stable hybrid nanofluids. The obtained data indicate that the hybrid nanofluids' thermal conductivity and specific heat enhance with increasing temperature and weight concentration. Almost 37.4% and 48.1% enhancement is observed in the thermal conductivity and specific heat, respectively, at 65 °C and 0.6% weight concentration. Thermal oil-based hybrid nanofluids display Newtonian behavior at low shear rates and an inverse relationship with temperature. Shear-thinning non-Newtonian behavior is observed at high shear rates and temperatures. A maximum increase in viscosity up to 22.0% is observed at 65 °C and 0.6% wt. concentration. The relative change indicates that all investigated properties have a significant impact, where the increasing trend of thermal conductivity and specific heat with increasing temperature and weight concentration of thermal oil-based hybrid nanofluids make them suitable for high-temperature heat transfer applications. [ABSTRACT FROM AUTHOR]

Reaction-bonded boron carbide composites were fabricated by molten silicon infiltration of diamond-containing boron carbide preforms. The effects of diamond particle size on the microstructure, mechanical and tribological properties of reaction-bonded boron carbide composites were investigated. Fine diamond particles (≤7.7 µm) completely reacted with silicon generating nano silicon carbide particles, which bonded the boron carbide particles forming a 3-D ceramic skeleton and improving the flexural strength of the composites. Coarser diamond (≥24 µm) particles were retained protected by a dense SiC layer generated from the reaction of diamond and molten silicon. A "core-shell" structure with the retained diamond as the "core" and with the reaction formed silicon carbide as the "shell" formed. Relief structures were established on the composites' surface during the wear process, greatly reducing the friction coefficient and improving the wear resistance. [ABSTRACT FROM AUTHOR]

Polycrystalline diamond compacts (PDC) with three different substrate geometries and trimodal diamond particle formulation were fabricated. The properties of prepared PDC including Vickers hardness, toughness, wear performance, and thermal stability were evaluated. The microscopic features including morphology, elemental and phase composition, and residual stress state were systematically investigated. The optimal substrate contributing to best comprehensive properties of PDC was singled out. Discrepancies in the properties of PDCs with different substrate geometries were mainly in fracture toughness and impact toughness, with maximum and minimum values of 6.54 MPa m1/2/3120 J and 5 MPa m1/2/1680 J, respectively. The best wear performance was 5.88 mm2/60P. The results showed that the tendency of wear performance was consistent with toughness and thermal stability, showing a strong correlation. The substrate geometry affected the morphology and composition of the cobalt transition layer in the interface, which had a significant impact on its toughness. Differences in residual stress states induced by the interfacial geometries were also important determining PDC's impact toughness. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC)-bonded diamond materials, comprising approximately 50% diamond by volume, represent innovative composites with exceptional mechanical and thermal properties, including high hardness, wear and corrosion resistance, and elevated thermal conductivity. Despite these advantageous properties, the machining of these composites presents formidable challenges due to their extremely high hardness. Grinding with diamond tools is commonly employed among the limited viable machining methods. However, the efficiency of this process is hindered by high grinding forces, elevated temperatures, and significantly high tool wear. Additionally, the surface integrity, form, and dimensional accuracy of the workpiece are compromised by the effects of tool wear and high cutting forces. To address these technological constraints in the grinding of SiC-bonded diamond materials, a laser-assisted grinding process has been developed. Ultra-short pulsed laser radiations were effectively utilized to induce material ablation with controlled structural damages, enhancing the productivity and efficiency of the grinding process through reduced grinding forces, temperatures, and tool wear. Furthermore, this study investigated the influence of grinding tools' specifications, design variations, and parameters on key aspects such as grinding forces, surface quality, and tool wear. Substantial reductions of up to 70% in tangential grinding forces, 83% in normal grinding forces, and a modest improvement in surface roughness achieved. The surface integrity analysis revealed a damage-free ground surface when utilizing laser assistance. Furthermore, there was a substantial enhancement in the grinding ratio (G-ratio), achieving an increase of up to 247%, concurrently with a noteworthy improvement in the actual removal depth, reaching up to 99%, when compared to conventional grinding processes. Compared to the utilized segmented metal bonded diamond grinding wheel, the vitrified bonded diamond grinding wheel induced lower grinding forces and higher actual removal rates. [ABSTRACT FROM AUTHOR]

The phase relations of Al-bearing magnetite were investigated between 6–22 GPa and 1000–1550 °C using a multi-anvil apparatus. This study demonstrates that the spinel-structured phase persists up to ~9–10 GPa at 1100–1400 °C irrespective of the amount of hercynite (FeAl2O4) component present (20, 40, or 60 mol%). At ~10 GPa, the assemblage Fe2(Al,Fe)2O5 + (Al,Fe)2O3 forms and remains stable up to 16–20 GPa and 1200–1550 °C. Fe2(Al,Fe)2O5 adopts the CaFe3O5-type structure with the Cmcm space group. At 18–22 GPa and T > 1300 °C the assemblage Fe3(Fe,Al)4O9 + (Al,Fe)2O3 becomes stable. Fe3(Fe,Al)4O9 is isostructural with Fe7O9, having the monoclinic structure of the C2/m space group. At T <1300 °C, Fe3(Fe,Al)4O9 + (Al,Fe)2O3 gives way to the assemblage of a hp-Fe(Fe,Al)2O4 + (Al,Fe)2O3. This hp-Fe(Fe,Al)2O4 phase is unquenchable; a defect-bearing spinel-structured phase was recovered instead, and it contained numerous lamellae parallel to {100} or {113} planes and notably less Al than the initial starting composition. While low-pressure spinel can have a complete solid solution between Fe3+-Al, the post-spinel phases have only very limited Al solubility, with a maximum of ~0.1 cpfu Al in hp-Fe(Fe,Al)2O4, ~0.3 cpfu in Fe2(Fe,Al)2O5, and ~0.4 cpfu in Fe3(Fe,Al)4O9, respectively. As a result, the phase relations of Fe(Fe0.8Al0.2)2O4 can also be applied to bulk compositions richer in Al with the only difference being that larger amounts of an (Al,Fe)2O3 phase are present. Coexisting rhombohedral-structured phases demonstrate that the binary miscibility gap established at low pressure between hematite and corundum is still valid up to 20 GPa. Since iron oxides (e.g., magnetite) with variable Al contents are found in extraterrestrial rocks or as inclusions in diamond, constraints on their high-P-T-fO2 stability might help unravel their formation conditions. [ABSTRACT FROM AUTHOR]

There is an extensive range of carbon substances with poorly ordered structures that are not well understood. Yet they are important indicators of conditions of related geological processes. The carbon minerals include nanocrystalline graphite, natural analogs of glass-like carbon (GLC)—shungite and impact ultrahigh-pressure GLC, recently discovered ultranocrystalline diamond, as well as natural carbon nanocomposites of diamond, lonsdaleite, and graphite. Studying these natural carbon substances using a standard Raman approach with excitation by visible radiation may lead to a significant distortion of the understanding of their phase states. This paper presents in detail for the first time the spectral features of natural, poorly ordered, and multiphase sp2-sp3 carbon composites by multi-wave Raman spectroscopy using laser excitations from visible to ultraviolet light applied to natural low-ordered carbon substances—nanocrystalline graphite and shungite, nanocrystalline and ultranocrystalline diamond, and multiphase carbon aggregates. The carbon state resolution advantages of ultraviolet Raman spectroscopy for phase analysis of nanostructured and poorly ordered polycomponent carbon substances containing sp2- and sp3-carbons are presented. Raman spectroscopy with ultraviolet excitation can also be applied in the analysis of industrial carbon materials, such as glassy carbon and functional carbon nanocomposites, including ultranocrystalline diamond, lonsdaleite, and amorphous sp3-carbon components. [ABSTRACT FROM AUTHOR]

For high dielectric constant, conductive carbide ceramic fillers are scattered in polymer to fabricate composites. However, high conductivity of carbides will lead to high leakage conductance and dielectric loss. In this work, to balance dielectric properties, polymer/ZrC/diamond blends were prepared via complementation of fillers. To perform property comparison, polymer/ZrC blends were prepared. Crystal forms and micromorphology of fillers were confirmed. All blends were measured to obtain dielectric constant, dielectric loss and conductivity at various frequencies. Compared to polymer/ZrC blends, dielectric constant of ternary blends slightly decreases and dielectric loss sharply reduces. By analysing ternary blends, strong interaction at polymer/ZrC interface results in high dielectric constant and insulating diamond results in low-dielectric loss via greatly-decreased leakage conductance. Partner employment of ZrC and diamond is distinctive. Ternary blend loaded with 5 wt% ZrC and 3 wt% diamond exhibits well-balanced dielectric performances (dielectric constant ~ 35.3; dielectric loss ~ 0.48) at 100 Hz. This work will provide valid route for balancing dielectric properties of polymer/conductive carbide blends. [ABSTRACT FROM AUTHOR]

The nitrogen-vacancy center in diamond attracts a lot of attention in sensing applications, mainly for temperature, magnetic field, and rotation measurements. Nuclear spins of carbon-13 surrounding the nitrogen-vacancy center can be used as a memory or sensing element. In the current work, a diamond plate with a relatively large concentration of carbon-13 was synthesized and examined. The spectrum of optically detected magnetic resonance was recorded and analyzed in a magnetic field range of 5–200 G. A strain-independent measurement technique of carbon-13 isotope concentration based on the analysis of magnetic resonance spectra was developed. Additionally, narrow features in the spectrum were detected and understood. [ABSTRACT FROM AUTHOR]

The roughness of the contact surface exerts a vital role in rubbing. It is still a significant challenge to understand the microscopic contact of the rough surface at the atomic level. Herein, the rough surface with a special root mean square (RMS) value is constructed by multivariate Weierstrass–Mandelbrot (W–M) function and the rubbing process during that the chemical mechanical polishing (CMP) process of diamond is mimicked utilizing the reactive force field molecular dynamics (ReaxFF MD) simulation. It is found that the contact area A/A0 is positively related with the load, and the friction force F depends on the number of interfacial bridge bonds. Increasing the surface roughness will increase the friction force and friction coefficient. The model with low roughness and high lubrication has less friction force, and the presence of polishing liquid molecules can decrease the friction force and friction coefficient. The RMS value and the degree of damage show a functional relationship with the applied load and lubrication, i.e., the RMS value decreases more under larger load and higher lubrication, and the diamond substrate occurs severer damage under larger load and lower lubrication. This work will generate fresh insight into the understanding of the microscopic contact of the rough surface at the atomic level. [ABSTRACT FROM AUTHOR]

Visualizing the near-field distribution of microwave field in a monopole antenna is very important for antenna design and manufacture. However, the traditional method of measuring antenna microwave near field distribution by mechanical scanning has some problems, such as long measurement time, low measurement accuracy and large system volume, which seriously limits the measurement effect of antenna microwave near field distribution. In this paper, a method of microwave near-field imaging of a monopole antenna using a nitrogen-vacancy center diamond is presented. We use the whole diamond as a probe and camera to achieve wide-field microwave imaging. Because there is no displacement structure in the system, the method has high time efficiency and good stability. Compared with the traditional measurement methods, the diamond probe has almost no effect on the measured microwave field, which realizes the accurate near-field imaging of the microwave field of the monopole antenna. This method achieves microwave near-field imaging of a monopole antenna with a diameter of 100 µm and a length of 15 mm at a field of view of 5 × 5 mm, with a spatial resolution of 3 µm and an imaging bandwidth of 2.7~3.2 GHz, and an optimal input microwave phase resolution of 0.52° at a microwave power of 0.8494 W. The results provide a new method for microwave near-field imaging and measurement of monopole antennas. [ABSTRACT FROM AUTHOR]

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The nitrogen−vacancy (NV) center in diamond gains its versatility when negatively charged (NV−) but is mediocre when neutrally charged. Particularly, the charge states of NV centers are convertible under optical pumping and during the dark intervals, whose dynamics are mixed with the NV−s' spin polarizations and relaxations, making them difficult to detect. Here, a microwave‐pulses‐assisted charge state dynamics (CSD) measurement method of NV centers in the dark time (DT) is proposed. The microwave pulses are designed to manipulate the populations of the NV−s' ground state spin triplets (qutrit) to the equilibrium state before the DT. Thus, the longitudinal relaxations of the qutrit are balanced, and pure CSD can be detected. Interestingly, in an annealed bulk diamond, not only the traditional tunneling‐induced fast exponential CSD are observed, but also a slow and long‐term recharging process, which is probably attributed to the exchanging of the electrons between NV centers and the high‐energy‐level charge traps such as vacancy clusters. Furthermore, results demonstrate a 40% increase in NV−s' contrast by properly extending the recharging DT. These results are significant for the in‐depth study of the NV centers' CSD and can improve the sensing abilities of the NV− ensemble. [ABSTRACT FROM AUTHOR]

Copper‐based diamond composites are widely used for thermal management and wear‐resistant materials. In this work, Cu/diamond, Cu/tungsten carbide (WC)/diamond, and Cu–0.92Cr/WC/diamond composites are fabricated by high‐energy ball milling and rapid hot‐pressing sintering. Physical characteristics, compressive strength, and tribological properties of the studied composites are investigated. The compressive strength of Cu/7wt%WC/diamond composites is 102% higher than the Cu/diamond composites, reaching 415 MPa. Compression fractures extend from the interface due to compression cracks, consistent with the compression curves from molecular dynamics (MD) simulations. The crack propagates from the interface during the compression experiment, which is consistent with the result of MD simulation. The Cu/7wt%WC/diamond composites exhibit a wear rate of 0.6 × 10−6 mm3 (N m)−1 and a friction coefficient of 0.37 at 50 N. The addition of WC and diamond improves the compressive strength and wear resistance. These findings are helpful in the development of copper composites with high compression strength and wear resistance. [ABSTRACT FROM AUTHOR]

This article has a methodical orientation. There are discussed the features of the use of silt mineralogical methods in the search for native and placer deposits of diamonds. The key points of the theory of the forming sedimentary reservoirs, which contain the scattering aureoles of satellite minerals and the placers of diamonds, are considered. In connection with the cyclicity of sedimentogenesis, during the formation of aureoles in diamond-bearing regions redeposition of kimberlite mineral associations occurs (often repeated). That is why they are not so common in the primary deposit. An indication of re-deposition is a discrepancy between the typomorphic features of minerals and the nature of the deposits that contain them. The main feature that makes it possible to distinguish redeposited associations is the discrepancy between the degree of the indicator minerals wearing and the facies appearance of the deposits. The alternation of the sedimentogenesis cycles and repeated deposition of minerals from earlier reservoirs into newly formed deposits leads to the accumulation of material from different eras of kimberlite erosion in aureoles and placers. The ratio and absolute contents of different generations of minerals in aureoles can be completely different. These parameters determine the degree of contrast of a particular aureole, which means the level of search efficiency. There are also considered the prospecting situations in various diamond-bearing provinces -- Angola, Brazil, Sakha-Yakutia, Ukraine. The features of the heavy concentrate mineralogical analysis in these regions are discussed also. There are given the general principles of using mineralogical methods in different landscape and geological conditions of the territories; the recommendations for carrying out a complex of works that must be performed to prepare the mineralogical and paleogeological basis for the forecast map. It is necessary for this to carry out a complex of studies, which includes the study of the typomorphism of indicator minerals, lithologic-facies and material features of the terrigenous deposits that contain them, and conducting paleogeological and paleogeographical reconstructions. The probability of the forecast and the effectiveness of searches using mineralogical methods depends on the consideration degree of the search conditions specifics in the structural-facies zones, the landscape-geological search conditions and the quality of paleoreconstructions. [ABSTRACT FROM AUTHOR]

The radiation-induced optical absorption at 1.5–5.5 eV (up to the beginning of fundamental absorption) has been analyzed in CVD diamond disks exposed to 231-MeV 132Xe ions with four fluences from 1012 to 3.8 × 1013 cm−2. The 5 mm diameter samples (thickness 0.4 mm) were prepared by Diamond Materials, Freiburg (Germany); the average grain size at growth site was around 80 μm; and the range of xenon ions was R = 11.5 μm. The intensity of several bands grows with ion fluence, thus confirming the radiation-induced origin of the defects responsible for these bands. The recovery of radiation damage has been investigated via isochronal (stepwise) thermal annealing procedure up to 650 °C, while all spectra were measured at room temperature. Based on these spectra, the annealing kinetics of several defects, in particular carbon vacancies (GR1 centers with a broad band ~2 eV) and complementary C-interstitial-related defects (~4 eV), as well as impurity-related complex defects (narrow bands around 2.5 eV) have been constructed. The experimental kinetics have also been analyzed in terms of the diffusion-controlled bimolecular reactions. The migration energies of tentatively interstitial atoms (mobile components in recombination process) are obtained, and their dependence on the irradiation fluences is discussed. [ABSTRACT FROM AUTHOR]

In our study, we utilize molecular dynamics simulations, specifically through the Reactive Empirical Bond Order, to unravel atomic-scale dynamics in graphite, an essential component in many advanced technologies, under varying irradiation scenarios. We shed light on the behavior of graphite when exposed to Primary Knock-on Atom (PKA) energies of 10, 20, 40, and 80 keV. The findings highlight the radiation vulnerability of graphite, especially when influenced by hydride inclusion. Both pristine graphite and its hydride variant exhibited an increase in Frenkel pairs (FPs) with escalating PKA energies. Notably, carbon PKAs manifested significant FP effects, whereas hydrogen PKAs influenced defect formation through variable diffusivity. In tested radiation scenarios, particularly in Mode C and the R1 region, cascade patterns identified distinct defect forms of diamond-like and elongated-diamond-like shapes, distinct from the typical PKA collision clusters. Furthermore, our cascade findings emphasize the formation of three-coordinated graphite rings, particularly as PKA energies increase. The graphite population statistics reveal a decline in threefold-coordinated atoms and an increase in other types of defects, with 7-carbon atom rings being the most common. Our research highlights the significance of understanding three-coordinated graphite rings, especially as PKA energies rise. Graphite population statistics reveal a decline in threefold-coordinated atoms and a rise in other defects. Notably, 7-carbon atom rings are the most common. From a clustering perspective, self-interstitial atom (SIA) clusters predominated in pristine graphite, while this trend balanced in the hydride variant. Our research highlights the importance of understanding atomic behaviors in graphite under several radiation scenarios. This knowledge is needed for advancing reliable and efficient technological applications, particularly in the field of nuclear technology. Our research underscores the need to understand atomic behaviors in graphite under radiation, paving the way for detailed study on reliable efficient technological applications. [ABSTRACT FROM AUTHOR]

Carbon nanomaterials are in high demand owing to their exceptional physical and chemical properties. This study employed a mixture of CH4, H2, and N2 to create carbon nanostructures on a single-crystal diamond using microwave plasma chemical vapor deposition (MPCVD) under high-power conditions. By controlling the substrate surface and nitrogen flow rate, carbon nanowires, carbon nanotubes, and carbon pompons could be selectively deposited. The results obtained from OES, SEM, TEM, and Raman spectroscopy revealed that the nitrogen flow rate and substrate surface conditions were crucial for the growth of carbon nanostructures. The changes in the plasma shape enhanced the etching effect, promoting the growth of carbon pompons. The CN and C2 groups play vital catalytic roles in the formation of carbon nanotubes and nanowires, guiding the precipitation and composite growth of carbon atoms at the interface between the Mo metal catalysts and diamond. This study demonstrated that heterostructures of diamond–carbon nanomaterials could be produced under high-power conditions, offering a new approach to integrating diamond and carbon nanomaterials. [ABSTRACT FROM AUTHOR]

In the absence of externally applied mechanical loading, it would seem counterintuitive that a solid particle sitting on the surface of another solid could not only sink into the latter, but also continue its rigid-body motion towards the interior, reaching a depth as distant as thousands of times the particle diameter. Here, we demonstrate such a case using in situ microscopic as well as bulk experiments, in which diamond nanoparticles ~100 nm in size move into iron up to millimeter depth, at a temperature about half of the melting point of iron. Each diamond nanoparticle is nudged as a whole, in a displacive motion towards the iron interior, due to a local stress induced by the accumulation of iron atoms diffusing around the particle via a short and easy interfacial channel. Our discovery underscores an unusual mass transport mode in solids, in addition to the familiar diffusion of individual atoms. It has long been believed that diffusion as individual atoms is the primary way for carbon to enter Fe crystals from outside. Here, the authors report an unusual mass transport way in solids, through which diamond nanoparticles can enter Fe spontaneously and translate inward for a long distance. [ABSTRACT FROM AUTHOR]

In multi-electrode devices, charge pulses at all the electrodes are induced concurrently by the motion of the excess charge carriers generated by a single ion. This charge-sharing effect is such that the pulse amplitude at each sensitive electrode depends on the device geometry, its overall electrostatic configuration, and the charge transport properties of the detecting material. Therefore, the cross-analysis of the charge pulses induced at each electrode offers implicit information on the position of the ion impact. In this work, we investigate the two-dimensional position sensitivity of a diamond detector fabricated by deep ion beam lithography. By exploiting the ion beam induced charge technique, the device was exposed to a 2 MeV Li+ ion micro-beam to map the spatial dependence of the charge collection efficiency (CCE) on the nominal micro-beam scanning position. The combination of the CCE maps revealed a two-dimensional position sensitivity of the device with micrometric resolution at the center of the active region. [ABSTRACT FROM AUTHOR]

Color centers in diamond are at the forefront of the second quantum revolution. A handful of defects are in use, and finding ones with all the desired properties for quantum applications is arduous. By using high-throughput calculations, we screen 21,607 defects in diamond and collect the results in the ADAQ database. Upon exploring this database, we find not only the known defects but also several unexplored defects. Specifically, defects containing sodium stand out as particularly relevant because of their high spins and predicted improved optical properties compared to the NV center. Hence, we studied these in detail, employing high-accuracy theoretical calculations. The single sodium substitutional (NaC) has various charge states with spin ranging from 0.5 to 1.5, ZPL in the near-infrared, and a high Debye-Waller factor, making it ideal for biological quantum applications. The sodium vacancy (NaV) has a ZPL in the visible region and a potential rare spin-2 ground state. Our results show sodium implantation yields many interesting spin defects that are valuable additions to the arsenal of point defects in diamond studied for quantum applications. [ABSTRACT FROM AUTHOR]

We employed polarization-sensitive nonlinear optical microscopy to assess crystallinity of diamond microneedles. In the experiment, we mapped the coherent anti-Stokes Raman spectroscopy (CARS) signal in the vicinity of 1332 cm−1 diamond Raman peak over the needle length and demonstrated that the third-order nonlinear optical susceptibility remains the same at both micrometer-sized base and the nanoscale thin apex of the needle. This indicated the single-crystal nature of the diamond needle and allowed us to describe the results of the polarization CARS measurements in terms of the third-order nonlinear susceptibility of diamond. High crystallinity of the needle was also confirmed by measuring the linewidth of the zero-phonon line of the silicon-vacancy centers in diamond. [ABSTRACT FROM AUTHOR]

Polycrystalline diamond compacts (PDCs) with varying amounts of vanadium were successfully sintered. The mechanical and thermal performance tests showed that the abrasion resistance, impact toughness, and thermal resistance increased by 69%, 202.9%, and 30 °C, respectively. The improved performance can be attributed to the solid solution formed by V 8 C 7 with tungsten carbide (WC) as a reinforcing phase, which eliminated interfacial defects, improved residual stress, and reduced the thermal expansion coefficient. In summary, we successfully developed a novel method for fabricating high-performance PDCs to enhance abrasion resistance and thermal stability, while substantially improving impact resistance, and which have remarkable application prospects. [ABSTRACT FROM AUTHOR]

AISI 420 is primarily used for optic molds manufactured through ultraprecision machining with single-crystal diamond tools. Tool wear rapidly occurs due to the diffusion of diamond and iron atoms when cutting ferrous metals with diamond tools. In the machining of optic molds, the diamond tool is uniformly replaced, regardless of the tool status after use for some time due to the difficulty in predicting tool life. This practice results in the wastage of expensive single-crystal diamond tools and reduces productivity. This study addressed the aforementioned issue by developing a tool-life model through theoretical analysis of the effective contact ratio between the tool and the workpiece and a cutting experiment with high-frequency ultrasonic vibration. In addition, the effectiveness of ultrasonic vibration cutting on the suppression of diamond tool wear was demonstrated by measuring tool wear after the cutting experiments. [ABSTRACT FROM AUTHOR]

The corrosion resistance of Cu/Diamond composite materials, a combination of copper and diamond, was investigated in aqueous conditions. A 3.5 % NaCl neutral salt spray was employed to assess the corrosion performance of the composite, considering factors such as surface appearance, corrosion rate, and corrosion depth. The results revealed that corrosion predominantly occurred within the copper matrix, while the diamond and interface components remained resistant to corrosion. Micro-galvanic corrosion was identified as the primary corrosion mechanism. Additionally, the incorporation of 5 % diamond particles led to a notable improvement in corrosion resistance, reaching 93.7 %. Although the salt spray environment did induce some changes in the composite surface, it did not significantly impact the overall properties of the composite. [ABSTRACT FROM AUTHOR]

In this study, diamond/silicon carbide (SiC) composites were prepared by liquid Si infiltration. The effects of the infiltration temperature on the densification, diamond graphitization, and thermal conductivity of the composites were investigated. The effects of the diamond content on the thermal conductivity and bending strength were also explored. X‐ray diffraction and Raman spectroscopy detected diamond graphitization at an infiltration temperature of 1480°C. Almost no graphitized diamond was observed due to reactions between silicon and carbon to form SiC at infiltration temperatures higher than 1480°C. As the infiltration temperature increased, graphitized diamond was consumed, and the thermal conductivity of the composite rose. The thermal conductivity and bending strength of the composites depended on the diamond content, reaching values of 257 W/m K and 237 MPa, respectively, for the sample with a diamond content of 17.9 vol.%. The higher bending strength was mainly ascribed to the high diamond content and well‐bonded interface. [ABSTRACT FROM AUTHOR]

The beamline optics and endstations at branch B of the Versatile Soft X-ray (VerSoX) beamline B07 at Diamond Light Source are described. B07-B provides medium-flux X-rays in the range 45-2200 eV from a bending magnet source, giving access to local electronic structure for atoms of all elements from Li to Y. It has an endstation for high-throughput X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine-structure (NEXAFS) measurements under ultrahigh-vacuum (UHV) conditions. B07-B has a second endstation dedicated to NEXAFS at pressures from UHV to ambient pressure (1 atm). The combination of these endstations permits studies of a wide range of interfaces and materials. The beamline and endstation designs are discussed in detail, as well as their performance and the commissioning process. [ABSTRACT FROM AUTHOR]

Electroplated diamond wire sawing is widely used as a processing method to cut hard and brittle difficult-to-machine materials. Currently, obtaining the sawing capability of diamond wire saw through the wire bow is still difficult. In this paper, a method for calculating the sawing capability of diamond wire saw in real-time based on the wire bow is proposed. The influence of the renewed length per round trip, crystal orientation of sapphire, wire speed, and feed rate on the wire sawing capability has been revealed via slicing experiments. The results indicate that renewing the diamond wire saw, and reducing the wire speed and feed rate can delay the reduction in sawing capability. Furthermore, controlling the value of renewed length per round trip can make the diamond wire saw enter a stable cutting state, in which the capability of the wire saw no longer decreases. The sawing capability of diamond wire saw cutting in the A-plane of the sapphire is smaller than that of the C-plane, and a suitable feed rate or wire speed within the range of sawing parameters studied in this study can avoid a rapid decrease in the sawing capability of the wire saw during the cutting process. The knowledge obtained in this study provides a theoretical basis for monitoring the performance of the wire saw, and guidance for the wire cutting process in semiconductor manufacturing. In the future, it may even be possible to provide real-time performance parameters of diamond wire saw for the digital twin model of wire sawing. [ABSTRACT FROM AUTHOR]

A novel DC-assisted fast hot-pressing (FHP) powder sintering technique was utilized to prepare Al/Diamond composites. Three series of orthogonal experiments were designed and conducted to explore the effects of sintering temperature, sintering pressure, and holding time on the thermal conductivity (TC) and sintering mechanism of an Al-50Diamond composite. Improper sintering temperatures dramatically degraded the TC, as relatively low temperatures (≤520 °C) led to the retention of a large number of pores, while higher temperatures (≥600 °C) caused unavoidable debonding cracks. Excessive pressure (≥100 MPa) induced lattice distortion and the accumulation of dislocations, whereas a prolonged holding time (≥20 min) would most likely cause the Al phase to aggregate into clusters due to surface tension. The optimal process parameters for the preparation of Al-50diamond composites by the FHP method were 560 °C-80 MPa-10 min, corresponding to a density and TC of 3.09 g cm−3 and 527.8 W m−1 K−1, respectively. Structural defects such as pores, dislocations, debonding cracks, and agglomerations within the composite strongly enhance the interfacial thermal resistance (ITR), thereby deteriorating TC performance. Considering the ITR of the binary solid-phase composite, the Hasselman–Johnson model can more accurately predict the TC of Al-50diamond composites for FHP technology under an optimal process with a 3.4% error rate (509.6 W m−1 K−1 to 527.8 W m−1 K−1). The theoretical thermal conductivity of the binary composites estimated by data modeling (Hasselman–Johnson Model, etc.) matches well with the actual thermal conductivity of the sintered samples using the FHP method. [ABSTRACT FROM AUTHOR]

Sublithospheric diamonds and the inclusions they may carry crystallize in the asthenosphere, transition zone, or uppermost lower mantle (from 300 to ∼800 km), and are the deepest minerals so far recognized to form by plate tectonics. These diamonds are distinctive in their deformation features, low nitrogen content, and inclusions of these major mantle minerals: majoritic garnet, clinopyroxene, ringwoodite, CaSi perovskite, ferropericlase, and bridgmanite or their retrograde equivalents. The stable isotopic compositions of elements within these diamonds (δ11B, δ13C, δ15N) and their inclusions (δ18O, δ56Fe) are typically well outside normal mantle ranges, showing that these elements were either organic (C) or modified by seawater alteration (B, O, Fe) at relatively low temperatures. Metamorphic minerals in cold slabs are effective hosts that transport C as CO3 and H as H2O, OH, or CH4 below the island arc and mantle wedge. Warming of the slab generates carbonatitic melts, supercritical aqueous fluids, or metallic liquids, forming three types of sublithospheric diamonds. Diamond crystallization occurs by movement and reduction of mobile fluids as they pass through host mantle via fractures—a process that creates chemical heterogeneity and may promote deep focus earthquakes. Geobarometry of majoritic garnet inclusions and diamond ages suggest upward transport, perhaps to the base of mantle lithosphere. From there, diamonds are carried to Earth's surface by eruptions of kimberlite magma. Mineral assemblages in sublithospheric diamonds directly trace Earth's deep volatile cycle, demonstrating how the hydrosphere of a rocky planet can connect to its solid interior. Sublithospheric diamonds from the deep upper mantle, transition zone, and lower mantle host Earth's deepest obtainable mineral samples. Low-temperature seawater alteration of the ocean floor captures organic and inorganic carbon at the surface eventually to become some of the most precious gem diamonds. Subduction transports fluids in metamorphic minerals to great depth. Fluids released by slab heating migrate, react with host mantle to induce diamond crystallization, and may trigger earthquakes. Sublithospheric diamonds are powerful tracers of subduction—a plate tectonic process that deeply recycles part of Earth's planetary volatile budget. [ABSTRACT FROM AUTHOR]

For single crystal diamond (SCD) to gain practical use in technical applications including solid state electronics, thin (< $1 ~\mu \text{m}$), doped epitaxial SCD layers with very low (<1 nm) surface roughness are required. Conventional SCD chemical mechanical polishing (CMP) processes are insufficient to meet the requirements of such applications because the material removal rate (MRR) is often characterized inappropriately, and the material removal uniformity is seldom considered. In this study, chemical vapor deposition (CVD) growth of two lightly boron doped (p-) epilayers was performed on 3° misoriented (100) high pressure high temperature substrates of 4.5 x $4.5 mm^{2}$ area. A subsequent 8-hour oxidative CMP process utilizing potassium permanganate and a novel self-leveling holder design decreased the average surface roughness from 3.83 nm and 1.57 nm to 0.20 nm and 0.16 nm for the two samples, respectively. MRRs were determined by evaluating five circular wear monitor structures in each sample by atomic force microscopy before and after the CMP process. The average MRRs were found to be 38.6 nm/hr and 37.3 nm/hr for the two samples. The purpose of this study is to demonstrate a CMP process suitable for polishing thin SCD epilayers to meet the needs of solid-state electronics applications. [ABSTRACT FROM AUTHOR]

When Harley Quinn (Margot Robbie) dressed as Lorelei (Marilyn Monroe) from 1953 film Gentlemen Prefer Blondes performs "Diamonds are a Girl's Best Friend" in Cathy Yan's 2020 film Birds of Prey (and the Fantabulous Emancipation of One Harley Quinn), links are drawn between 70 years of film history and women's representation on screen. In this article, I put various iterations of "Diamonds" into dialogue to explore how this moment in Birds of Prey might be understood. I consider this scene as central to understanding Quinn's "emancipation," with the representation of women's security and control over their lives key themes in the history of this scene. The return to this song throughout the histories of film and video enables a sense of solidarity across time, acknowledging the systemic problems that remain unresolved, and contemplation of this can alter the ways we understand characters and texts, past, present, and future. [ABSTRACT FROM AUTHOR]

Global bandwidth scarcity and escalation in energy consumption in the next-generation wireless communication sector has motivated the research and exploration of non-orthogonal multiple access (NOMA) powered with radio frequency (RF) energy harvesting. With the motivation of taking advantage of energy efficiency (EE) as well as spectral efficiency, this article focuses on analysing the performance of an autonomous and energy-efficient RF-powered multi-device diamond relay network in an Internet of things (IoT) environment using an improved adaptive NOMA (A-NOMA) protocol. Here, the IoT relay devices within a certain selection range employ NOMA, and the rest adopt orthogonal multiple access (OMA) functionality for information decoding. A-NOMA transmission technique determines the best multiple access protocol on the basis of maximum achievable sum rate (ASR). Closed form expressions of ASR and EE have been derived under Rayleigh fading environment and validated through extensive Monte Carlo simulations. Using the expressions, the overall sum rate of the proposed system has been evaluated and a noticeable improvement in ASR has been obtained for the investigated framework over similar system models devised using OMA and NOMA. In addition, bit error rate analysis has been carried out and compared with the existing benchmarks. Lastly, an in-depth analysis on EE with respect to ASR has also been performed. Simulation results demonstrate the effectiveness of our investigated model over the existing state of art and unveil interesting trade-off between EE and ASR. [ABSTRACT FROM AUTHOR]

Introduction: To assess the efficacy and safety of the combination of microblepharoexfoliation (MBE), intense pulse light (IPL) and meibomian gland expression (MGX) for treatment of meibomian gland dysfunction (MGD). Methods: This was a prospective, parallel-control trial conducted from April 2022 to January 2023. Participants were assigned to receive either three sessions of MBE-IPL-MGX treatment and home-based therapy (treatment group) or home-based therapy alone (control group). Outcome measures were assessed at baseline and after 2-month follow-up. Results: Seventy eyes of 70 patients were enrolled. MBE-IPL-MGX treatment achieved better improvements than home-based therapy in ocular surface disease index (OSDI) and symptom assessment in dry eye (SANDE) scores, noninvasive tear film break-up time (NIBUT), lipid layer grade (LLG), loss area meibomian gland (LAMG) and meibomian gland yielding secretion score (MGYSS). The mean differences between the two groups were as follows: OSDI (– 11.23 ± 4.68 points, P < 0.001), SANDE (– 24.63 ± 13.41 points, P < 0.001), NIBUT (1.3 ± 1.57 s, P = 0.033), LLG (0.4 ± 0.04 points, P = 0.003), LAMG (– 2.85 ± 1.69%, P = 0.023) and MGYSS (7.5 ± 2.32 points, P < 0.001). In addition, the increment (Δ) of MGYSS after MBE-IPL-MGX treatment was significantly higher in MGD grades 2 and 3 (all P < 0.001). Conclusions: MBE-IPL-MGX treatment is an effective and well-tolerated procedure that improves dry eye symptoms and signs as well as meibomian gland secretions in patients with MGD. In addition, this treatment is recommended for MGD grades 2 and 3. [ABSTRACT FROM AUTHOR]

Here we have performed single-crystal X-ray diffraction (SCXRD) experiments on two high-quality crystal platelets of (Al,Fe)-bearing bridgmanite (Mg0.88 F e 0.065 3 + F e 0.035 2 + Al0.03)(Al0.11Si0.90)O3 (Fe10-Al14-Bgm) up to 64.6(6) GPa at room temperature in a Boehler-Almax type diamond-anvil cell. Refinements on the collected SCXRD patterns reveal reliable structural information of single-crystal Fe10-Al14-Bgm, including unit-cell parameters, atomic coordinates, and anisotropic displacement parameters. Together with Mössbauer and electron microprobe analyses, our best single-crystal refinement model indicates that the sample contains ~6.5 mol% Fe3+, 3.5 mol% Fe2+, and 3 mol% Al3+ in the large pseudo-dodecahedral site (A site), and ~11 mol% Al3+ in the small octahedral site (B site). This may indicate that Al3+ in bridgmanite preferentially occupies the B site. Our results show that the compression of Fe10-Al14-Bgm with pressure causes monotonical decreases in the volumes of AO12 pseudo-dodecahedron and BO6 octahedron (VA and VB, respectively) as well as the associated A-O and B-O bond lengths. The interatomic angles of B-O1-B and B-O2-B decrease from 145.2–145.8° at 4.2(1) GPa to 143.3–143.5° at 64.6(6) GPa. Quantitative calculations of octahedral tilting angles (Φ) show that Φ increases smoothly with pressure. We found a linear relationship between the polyhedral volume ratio and the Φ in the bridgmanite with different compositions: VA/VB = –0.049Φ + 5.549. Our results indicate an increased distortion of the Fe10-Al14-Bgm structure with pressure, which might be related to the distortion of A-site Fe2+. The local environmental changes of A-site Fe2+ in bridgmanite could explain previous results on the hyperfine parameters, abnormal lattice thermal conductivity, mean force constant of iron bonds and other physical properties, which in turn provide insights into our understanding on the geophysics and geochemistry of the planet. [ABSTRACT FROM AUTHOR]

There are similarities between Bernard Williams and Cora Diamond as moral philosophers: both their moral philosophies are marked by an engagement with the question of what it is like to be a human being, and both are engaged with experience more than theory. Still, such similarities rest on very different philosophical grounds. In this article, I consider whether a Nietzschean (Williams) and a Wittgensteinian (Diamond) could ever converge on a characterization of the 'moral point of view' as this involves views on life, thought, and language. I argue that divergences between Williams and Diamond persist, a very important one concerning relativism: whereas Diamond adumbrates a Wittgensteinian way out of relativism, it remains a last word for Williams. [ABSTRACT FROM AUTHOR]

In the processing of quantum computation, analyzing and learning the pattern of the quantum data are essential for many tasks. Quantum machine learning algorithms cannot only deal with the quantum states generated in the preceding quantum procedures, but also the quantum registers encoding classical problems. In this work, the anomaly detection of quantum states encoding audio samples with a three‐qubit quantum processor consisting of solid‐state spins in diamond is experimentally demonstrated. By training the quantum machine with a few normal samples, the quantum machine can detect the anomaly samples with a minimum error rate of 15.4%. These results show the power of quantum anomaly detection in dealing with machine learning tasks and the potential to detect abnormal output of quantum devices. [ABSTRACT FROM AUTHOR]

With the consumption of shallow resources on the earth, the exploration and development of resources are constantly marching to the depth, and the conditions of strata encountered are becoming more and more complicated. Hard and dense formations, strong abrasive formations, and other complicated strata conditions have been a major hindrance to deep drilling. The diamond bits are widely used in geological resource development. Therefore, the comprehensive performance requirements of diamond bits are also increased. However, the existing diamond bits can only be applied to a certain formation and need to be replaced frequently, therefore, the research and development of broad-spectrum diamond bits with excellent formation applicability, high drilling efficiency, and long bit life is an important part of overcoming the deep drilling tasks. In recent years, the diamond drill bit has been developed rapidly, the structure, category, and performance have been greatly improved, and there also exists a certain improvement space. Therefore, this paper introduces the research status and important achievements of broad-spectrum diamond drills in recent years, including the improvement and application of drill structure and matrix performance, and then puts forward the research problems and future development direction of diamond drills with respect to the existing research results of broad-spectrum diamond drills. By summarizing the development trend of broad-spectrum diamond bits in this paper, the new research direction of diamond bit making technology and application field was revealed, which is of reference significance to the research and development of broad-spectrum diamond bits in the field of oil and gas exploration and mineral resources development. [ABSTRACT FROM AUTHOR]

This study proposed a novel double-layer junction termination structure for vertical diamond-based PN junction diodes (PND). The effects of the geometry and doping concentration of the junction termination structure on the PNDs' electrical properties are investigated using Silvaco TCAD software (Version 5.0.10.R). It demonstrates that the electric performances of PND with a single n-type diamond layer are sensitive to the doping concentration and electrode location of the n-type diamond. To further suppress the electric field crowding and obtain a better balance between breakdown voltage and on-resistance, a double-layer junction termination structure is introduced and evaluated, yielding significantly improved electronic performances. Those results provide some useful thoughts for the design of vertical diamond PND devices. [ABSTRACT FROM AUTHOR]

Single-crystal diamond possesses exceptional physical and optical properties, rendering it an ideal platform for integrated quantum optics. The direct integration of broadband-sensitive and high-performance single-photon detectors on diamond holds significant implications for the realization of integrated diamond quantum optical circuits. In this study, we polished the diamond surface with RMS (root mean square) below 0.6 nm suitable for the deposition and patterning of NbN thin films through ion beam etching. Subsequently, we fabricated superconducting nanowire single-photon detectors directly on the polished diamond substrates and characterized for their electrical and optical properties. The NbN-SNSPD exhibited a high critical current density (2 MA cm−2), a saturated quantum efficiency (QE) below 2.5 K, and a maximum value of QE up to 88% at 4 K. These findings offer a promising solution for fully integrated quantum optical chips on single-crystal diamond substrates. [ABSTRACT FROM AUTHOR]

Diamond possesses extremely excellent properties, which make it a potentially transformative material in an extensive range of applications. Herein, diamonds were synthesized in a FeNiCo–C system with B2S3 as an additive by a temperature-gradient growth method at high temperature and high pressure (HPHT) conditions. The effects of the B2S3 additive in the FeNiCo–C system on diamond crystallization were characterized using Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) measurements. FTIR result shows the presence of positive-charged N+ in the diamond crystal synthesized with the B2S3 additive, and its concentration was estimated to be around 30 ppm. Moreover, the XPS measurements confirm that N+ can combine with boron to form a B–N bond. Furthermore, the Hall effect result indicates that the resistivity of the diamond crystal synthesized with B2S3 was reduced to 3.89 × 10 Ω cm, whereas, the resistivity of the diamond synthesized with the same weight of B2S3 additive along with Ti/Cu as the nitrogen removal agent dropped sharply to 2.51 × 10−1 Ω cm. [ABSTRACT FROM AUTHOR]

The multilevel encoding (MLE) scheme is an effective method for improving the anticounterfeiting encryption capabilities of physically unclonable functions (PUFs). However, owing to the correlation between encoding layers, the encoding capacity (EC) is difficult to improve by orders of magnitude. Herein, four noncorrelated structures in the diamond crystal structure (carbon–carbon single bond, defect luminescence structures, spin structures, and electron energy distribution structures) are considered for MLE. First, the microdiamonds containing nitrogen‐vacancy (NV) color centers are embedded into polydimethylsiloxane (PDMS) to fabricate PUFs. Using an optical imaging system, four codable images of four noncorrelated structures are read. The noncorrelation of the four‐level encoding structure is verified by calculating the Hamming distance (0.496 ± 0.02). The results show that EC exponentially improves to 24×10 000/(100 pixels)2. Furthermore, the encoding method based on the energy level does not depend on physical structure parameters, such as the size and position of the spin structure. Thus, it is protected from structural modeling attacks, resulting in high security. Moreover, PUF labels based on PDMS flexible substrates can be employed for various flexible applications. In the proposed scheme, the information is encrypted by a four‐level two‐dimensional (2D) barcode and decoded by self‐developed PUF authentication software. The proposed scheme presents a way for developing next‐generation PUFs with super‐high EC. [ABSTRACT FROM AUTHOR]

The advent of additively manufactured biodegradable porous metals presents a transformative opportunity to meet the criteria of ideal bone substitutes. Precisely tailoring their degradation behavior constitutes a pivotal aspect of this endeavor. In this study, we investigated the effects of topological designs on the degradation profile of laser powder bed fusion (LPBF) Zn scaffolds under dynamic in vitro immersion tests. Specifically, four types of Zn-0.4Mn-0.2Mg scaffolds (beam-based: diamond, face center cubic; surface-based: gyroid, schwarz-P) were designed and fabricated. The degradation mechanism of the scaffolds was comprehensively evaluated using both experimental and simulation methods. The results illuminate the profound impact of structural design on the degradation properties of the Zn alloy scaffolds. The beam-based diamond and face center cubic scaffolds exhibited a degradation rate of 0.08–0.12 mm per year with a relatively uniform degradation mode under dynamic immersion. On the contrary, the surface-based gyroid and Schwarz-P scaffolds demonstrated a notably reduced degradation rate due to lower permeability. This restricted the diffusion of medium ions within the pores, culminating in the accumulation of degradation products and more severe localized degradation. This study underscores the potential of topological design as a compelling strategy for tailoring the degradation profile of additively manufactured biodegradable scaffolds, thereby advancing their suitability as bone substitutes. [ABSTRACT FROM AUTHOR]