High-pressure Method Research Articles

Robust Crystal Phase Separation with Distinct Charge, Orbital, and Spin Orders in AgMn7O12.

An AA'3B4O12-type A-site-ordered quadruple perovskite oxide AgMn7O12 was prepared by high-pressure and high-temperature methods. At room temperature, the compound crystallizes into a cubic Im3̅ symmetry with a charge distribution of AgMn33+Mn43.5+O12. With the temperature decreasing to TCO,OO ≈ 180 K, the compound undergoes a structural phase transition toward a monoclinic C2/m symmetry, giving rise to a B-site charge- and orbital-ordered AgMn33+Mn23+Mn24+O12 phase. Moreover, this charge-/orbital-ordered main phase coexists with the initial cubic AgMn33+Mn43.5+O12 phase in the wide temperature range we measured. The charge-/orbital-ordered phase shows two antiferromagnetic phase transitions near 125 and 90 K, respectively. Short-range ferromagnetic correlations are found to occur for the initial B-site mixed cubic phase around 35 K. Because of the robust phase separation, considerable magnetoresistance effects are observed below TCO,OO in AgMn7O12.

High-pressure hydrothermal dope Ce into MoVTeNbOx for one-step oxidation of propylene to acrylic acid

A high-pressure hydrothermal method was employed to introduce Ce element facilely into MoVTeNbOx catalysts in 0.5 h. It was indicated that Ce atoms were doped into the framework of MoVTeNbOx without changing the unique crystal structure of MoVTeNbOx. The introduction of Ce could facilitate the formation of oxygen vacancies and improve the redox ability of surfacial V. However, it was worth noting that the doping amount of Ce was negatively related to the content of M1 active phase. Within a certain range, the catalytic performance could be improved by sacrificing an appropriate amount of M1 phase. In the conversion of propylene to acrylic acid, the highest yield of 58.2% was obtained under catalyst MoVTeNbCeOx (V: Ce =1: 0.05) at 380 °C with the M1 phase content of 81.6%. The appropriate amount of Ce doping improved the propylene conversion by more than 20% compared to undoped. Moreover, the changes in Gibbs free energy of the rate-limiting step of direct oxidation of propylene before and after Ce doping were evaluated by Density functional theory (DFT). It is illustrated that the doping of Ce is thought to affect the main reason for the reduction of Gibbs free energy.

Corrosion behaviors of TA2 and TA36 titanium alloys in a high-sulfur environment

The mixed medium of sulfur, H2S, CO2, and generated water in the developed sour gas fields in Sichuan-Chongqing Gasfield seriously corrodes pipelines. The carbon steel gathering system is not suitable for transporting such a medium and titanium alloy has become a hotspot due to its high specific strength and excellent resistance to H2S corrosion. The corrosion of titanium and titanium alloys in the mixed media of H2S, CO2, and water has been extensively explored, but their electrochemical corrosion behaviors in the presence of elemental sulfur are not clear. In this study, the effects of temperature and sulfur on the corrosion behaviors and electrochemical behaviors of TA2 and TA36 in the simulated solution were studied with hanging tests and high-temperature and high-pressure electrochemical corrosion method and the corrosion morphology was observed with a scanning electron microscope. When the temperature increased from 60 °C to 90 °C, the self-corrosion current of TA36 alloy was decreased by one order of magnitude and the corrosion rate of TA36 decreased, indicating the improved corrosion resistance. At the same temperature, the self-corrosion current of TA36 alloy was 28.8 % of that of TA2 and the corrosion resistance of TA36 alloy was better than that of TA2. Sulfur deposition accelerated the pitting corrosion of TA2 and TA36.

Experimental study of the bilateral asymmetric single-rivet occluder device for transcatheter patent foramen ovale closure with reserved interatrial septal puncture area.

To evaluate a noval bilateral asymmetric single-rivet occluder with reserved interatrial septal puncture area for treating patent foramen ovale (PFO). The study established a pig model of patent foramen ovale (PFO) by puncturing the oval fossa and then performing high-pressure balloon dilation. A specially designed bilateral asymmetric occluder for the reserved interatrial septal puncture area was then. used to close the PFO through catheter-based intervention. The pigs were kept for 3 months before undergoing a second catheter-based intervention, involving interatrial septal puncture using a newly developed occluder in the reserved interatrial septal puncture area. During 6 months, the experimental pigs underwent assessment using digital subtraction angiography (DSA), echocardiography, and histological evaluation. A patent foramen ovale (PFO) model was successfully established in 6 pigs using the puncture atrial septum high-pressure balloon dilation method. The diameter of the unclosed PFO was measured (3.56 ± 0.25 mm). Using the newly developed occluder device, all 6 pigs with unclosed PFO underwent successful catheter-based closure surgeries, with intraoperative and postoperative transesophageal echocardiography showing excellent device positioning and complete closure without residual shunting. After 3 months of implantation, the catheter-based interatrial septal puncture was performed through the reserved interatrial septal puncture area, and all procedures were successful. Immediately following euthanasia, a histological examination revealed intact and undamaged occluder devices with visible puncture holes in the reserved interatrial septal puncture area. No fracture of the nitinol wire was observed, and the surface of the occluder device showed coverage of endothelial and connective tissues. Utilizing a bilateral asymmetric single-rivet occluder device implanted through the reserved interatrial septal puncture area has proven effective in closing PFO. After implantation, the occluder device allows subsequent interatrial septal puncture procedures through the reserved area. The novel occluder device demonstrated excellent closure performance, biocompatibility, and puncturability in the experiment. This indicates the feasibility of conducting further catheter-based interventions on the interatrial septum.

Facile synthesize and enhanced thermoelectric performance of PbS with Cl doping and PbSe alloying

Besides inferior conversion efficiency, the widespread application of thermoelectric materials currently faces the challenges of the rare and high cost of constituent elements, complex and time-consuming synthesis. Therefore, it is urgent to develop facile synthesized methods and high-performance thermoelectric materials consisting of elements with earth-abundance and low cost. Meeting above partial requirement, lead sulfide (PbS) recently was identified as a potential thermoelectric material to substitute current commercial PbTe. In this paper, a one-step high-pressure method was employed to facile and fast synthesis of PbS. Trace Cl doping tunes the carrier concentration of PbS effectively, which optimizes the electrical transport properties. Further PbSe alloying sharply reduces the thermal conductivity of PbS. Therefore, an enhanced zT∼1.0 @ 700 K was obtained for PbS doped with 0.3 at% Cl and alloyed with 25 at% PbSe, which is comparable to the commercially applied PbTe. These results indicate that high-pressure combing with Cl-doping and PbSe-alloying provide a facile method and strategy to fabricate high-performance PbS-based thermoelectric materials.

Silica-based ceramic cores for high-pressure turbine airfoil blades in aircraft engines

Ceramic cores for high-pressure turbine airfoil blades in aircraft engines are characterised by very complicated shapes and the presence of small diameter holes and thin long grooves. In this paper, eight starting powder mixtures having different contents of fused silica, zirconium silicate, alumina and borosilicate glass were used for preparation of core material. The composition, which satisfies every demand for core application in the investment casting of high-pressure turbine blades, contains 69.0wt.% fused silica, 13.0 wt.% zirconium silicate, 12.0wt.% alumina and 6.0wt.% borosilicate glass. This material was characterised by a mechanical strength of 33.1MPa, a coefficient of thermal expansion of 2.56 ? 10?6 1/K, surface roughness of 1.8 ?m, shrinkage of less than 0.8% and an average pore size diameter of 2.7 ?m. The thin-walled ceramic cores were formed by the high-pressure injection moulding method, which required the selection of a thermoplasticiser, feedstock formulation and determination of the optimal processing conditions protecting the injected cores from defects and deformation. The post-shaping process of the cores included both water and thermal debinding, sintering, precision machining and dimension measurements.

Mechanism of desorption hysteresis in coalbed methane: Insights from microscopic pore properties and adsorption theory

Desorption hysteresis, a phenomenon frequently observed in coal–methane desorption experiments, holds significant implications for coalbed methane extraction due to its influence on the volume of methane involved in migration. Yet, the precise mechanism behind desorption hysteresis remains incompletely understood. This study endeavors to elucidate the underlying mechanism of desorption hysteresis by considering pore characteristics and applying adsorption theory. The pore morphology was assessed using the physisorption method, and ad/desorption isotherms were measured using high-pressure volumetric methods, with the desorption hysteresis index (DHI) utilized to quantify the degree of hysteresis. The results pointed to the pivotal role of micropores (<1.5 nm) in the occurrence of desorption hysteresis. Enhanced specific surface area and pore volume, in conjunction with a decrease in the fractal dimension Ds of micropores, were found to correspond to higher DHI values. Conversely, an increase in meso/macropores (>1.5 nm) corresponded to reduced DHI. The Frenkel–Halsey–Hill fractal dimension showed no substantial correlation with DHI. In light of these findings, it is concluded that micropores, acting as gas entrapment spaces, primarily govern desorption hysteresis, while meso/macropores serve as migration pathways with lesser influence. Micropores exhibit robust adsorption capacity, leading methane molecules to preferentially occupy these spaces. However, during desorption, insufficient potential energy impedes the release of methane molecules from the coal surface, causing desorption hysteresis. These insights offer a fresh perspective on understanding the mechanism of desorption hysteresis in coal, which may prove valuable in optimizing methane extraction.

A magnetite reference material for in situ Fe isotope analysis

A high-temperature and high-pressure sintering method was used to prepare magnetite (MtFe-1), which can be used as a matrix-matched bracketing standard for Fe isotope analysis of natural magnetite using LA-MC-ICP-MS.

The layered RuBr3–RuI3 honeycomb system

A honeycomb layered Ru(Br1−xIx)3 solid solution is prepared through a high-pressure synthesis method, with anion disorder and strong spin–orbit coupling. Their electronic and magnetic properties vary dramatically with changing chemical composition.

Combination of Indomethacin with Nanostructured Lipid Carriers for Effective Anticancer Therapy.

The anticancer potential of indomethacin and other nonsteroidal anti-inflammatory drugs (NSAIDs) in vitro, in vivo, and in clinical trials is well known and widely reported in the literature, along with their side effects, which are mainly observed in the gastrointestinal tract. Here, we present a strategy for the application of the old drug indomethacin as an anticancer agent by encapsulating it in nanostructured lipid carriers (NLC). We describe the production method of IND-NLC, their physicochemical parameters, and the results of their antiproliferative activity against selected cancer cell lines, which were found to be higher compared to the activity of free indomethacin. IND-NLC were fabricated using the hot high-pressure homogenization method. The nanocarriers were physicochemically characterized, and their biopharmaceutical behaviour and therapeutic efficacy were evaluated in vitro. Lipid nanoparticles IND-NLC exhibited a particle size of 168.1 nm, a negative surface charge (-30.1 mV), low polydispersity index (PDI of 0.139), and high encapsulation efficiency (over 99%). IND-NLC were stable for over 60 days and retained integrity during storage at 4 °C and 25 °C. The potential therapeutic benefits of IND-NLC were screened using in vitro cancer models, where nanocarriers with encapsulated drug effectively inhibited the growth of breast cancer cell line MDA-MB-468 at dosage 15.7 μM. We successfully developed IND-NLC for delivery of indomethacin to cancer cells and confirmed their antitumoral efficacy in in vitro studies. The results suggest that indomethacin encapsulated in lipid nanoparticles possesses high anticancer potential. Moreover, the presented strategy is highly promising and may offer a new alternative for future therapeutic drug innovations.

Structure and magnetic properties of nanocrystalline SmCo5 and SmCo3Cu2 prepared by using high-pressure torsion method

Nanocrystalline SmCo5 and SmCo3Cu2 alloys were prepared by using high pressure torsion (HPT) method. The effect of severe plastic deformation of HPT on the structure and magnetic properties of the samples were investigated systematically. The grain size of SmCo5 and SmCo3Cu2 alloys was refined to the nanocrystalline regime or even amorphous state by HPT, depending on the number of the HPT rotation. Lamellar microstructures of the grains were observed in the samples after HPT for 2 turns of rotation. With increasing number of HPT rotation, a further structural refinement and an increasing coercivity were observed. The coercivity of the as-cast SmCo5 and SmCo3Cu2 alloys after HPT reached up to 0.5 and 1.64 T, respectively. This work demonstrates that HPT is a high efficiency method in producing bulk nanocrystalline magnetic materials.

Attempts to Electrochemically Synthesize Palladium Superhydrides By High Pressure Method – Combination of Electrolytic Hydrogen Charging and Electroplating of Protective Coatings –

IntroductionIncited by the possibility of room-temperature superconductors in superhydrides, numerous them have been synthesized using a diamond anvil cell under high pressures up to several hundred GPa. Although palladium has widely researched for a long time as a prototype hydrogen-absorbing metal, the palladium superhydrides has not yet been obtained under such high pressures. A recent theorical calculation has predicted that the palladium superhydrides (e.g., PdH10) may be synthesized by combing electrolysis and high pressure1), but it is not certain whether it can be achieved. In this study, we attempted to synthesize the palladium superhydrides by using electrolytic hydrogen charging under high pressures, and subsequently applied protective coatings to suppress the hydrogen desorption from the palladium hydrides at ambient pressure.ExperimentalFigure shows a schematic illustration of the high-pressure apparatus. The high-pressure apparatus can apply the pressure of up to 400 MPa to the electrolyte in the electrolytic cell by pumping water into a sealed high-pressure vessel using a plunger pump and pressure multipliers. A cold-rolled palladium foil of 30 ~ 40 μm in thickness was used as a cathode, and a zinc plate was utilized as a soluble anode. Hydrogen was electrochemically loaded into the palladium foil at 0 V vs. Zn in an electrolyte consisting of 0.1 mol dm-3 sulfuric acid and 4.6 mmol dm-3 zinc sulfate under various pressures for 6 hours. Subsequently, the palladium foil was coated with the zinc film at constant current density 25 mA cm-2 for 120 seconds under the high pressure. The specimen was removed from the electrolytic cell in the high-pressure vessel at ambient pressure, and the hydrogen concentration of the palladium hydride PdH x was determined by thermal desorption spectroscopy. Structural analysis was conducted using X-ray diffraction and scanning electron microscopy.Results and discussionA number of bubbles were observed on the palladium foil surface during the electrolytic charging at ambient pressure. On the other hand, no bubbles were observed at 300 MPa. The zinc film with approximately 1.4 μm thick was coated on the PdH x surface after the electrolytic hydrogen charging. The hydrogen concentration of the PdH x was approximately x = 0.7 immediately after synthesis, which decreased to x = 0.2 without the zinc coating. On the other hand, the hydrogen concentration of the PdH x was maintained at least 1 week with the zinc coating. This result indicates that the zinc film acts as a barrier to hydrogen desorption from PdH x , and suggests that if the palladium superhydrides could be synthesized by electrolytic hydrogen charging under high pressure, it could be taken out to ambient pressure while maintaining its concentration.Reference1) W. Guan, R. J. Hemley, and V. Viswanathan, PNAS, 118, e2110470118 (2021) Figure 1

Green and effective route to convert chromium-free leather waste into protein retarding material for building gypsum

Leather manufacturing generates a large amount of leather solid waste, among which the effective treatment of leather waste scraps rich in protein resources has always been a challenge for the tanning industry. In this paper, a green and convenient method was devised for the first time to prepare protein retarding material (PRM) for gypsum from chrome-free tanned leather waste. Aldehyde tanned leather scraps as the main chrome-free leather waste were directly hydrolyzed through high-pressure hydrothermal treatment without any chemicals to obtain PRM. Compared with chemical treatment (acid or alkaline hydrolysis), high-pressure hydrothermal method avoided the decrease of protein product purity due to without the help of acid and alkali. The results showed that PRM obtained from leather waste had a significant effect on prolonging the initial setting time and delaying the release of hydration heat of gypsum. With the dosage or molecular weight of PRM increased, this retarding effect on gypsum was more remarkable. SEM, XRD, and FTIR analysis indicated that the presence of PRMs inhibited the hydration process of gypsum hemihydrate to gypsum dihydrate. Through polypeptide-calcium chelation, PRMs could bind free Ca2+ ions dissolved from gypsum to delay them from participating in the hydration reaction. The larger molecular weight or the more dosage of PRM, the stronger ability to bind calcium ions in gypsum. Chemical structure characterization and molecular dynamics simulation of PRM-Ca chelate further proved that PRMs mainly through carboxyl groups on molecular chain combined with Ca2+ in gypsum system to inhibit hydration reaction, thereby fulfilling the retardation demand. This study indicated that PRM from leather scraps can be a promising candidate for gypsum retardation, which provides a path for the efficient utilization of leather waste.

Atomically Unraveling Highly Crystalline Self-Intercalated Tantalum Sulfide with Correlated Stacking Registry-Dependent Magnetism.

In self-intercalated two-dimensional (ic-2D) materials, understanding the local chemical environment and the topology of the filling site remains elusive, and the subsequent correlation with the macroscopically manifested physical properties has rarely been investigated. Herein, highly crystalline gram-scale ic-2D Ta1.33S2 crystals were successfully grown by the high-pressure high-temperature method. Employing combined atomic-resolution scanning transmission electron microscopy annular dark field imaging and density functional theory calculations, we systematically unveiled the atomic structures of an atlas of stacking registries in a well-defined √3(a) × √3(a) Ta1.33S2 superlattice. Ferromagnetic order was observed in the AC' stacking registry, and it evolves into an antiferromagnetic state in AA/AB/AB' stacking registries; the AA' stacking registry shows ferrimagnetic ordering. Therefore, we present a novel approach for fabricating large-scale highly crystalline ic-2D crystals and shed light on a powerful means of modulating the magnetic order of ic-2D systems via stacking engineering, i.e., stackingtronics.

A Rock Mass Classification Method for Tuff Tunnel Based on the High-Pressure Gas Expansion Method

A precise rock mass grade result is crucial for directing the tunnel excavation engineering design. A novel rock mass classification method for tuff tunnel based on the high-pressure gas expansion method (HPGEM) was proposed, which was primarily built on field test data previously acquired by the research team. The main achievements are as follows: combined with field data and the HPGEM rock-breaking theory, analyzing the rock uniaxial compressive strength, rock mass integrity index, and the relationship between the gas generator unit consumption and fitted the relevant equations. After that, the rock optimal uniaxial compressive strength (about 150 MPa) and the rock integrity factor (about 0.85) were obtained. With reference to the BQ rock mass classification method, a new rock mass classification method that applied to HPGEM was proposed. This study fills the gap of the appropriate rock mass classification method requested on HPGEM.

The Influence of Site of Co and Holes in PCD Substrate on Adhesive Strength of Diamond Coating with PCD Substrate

Polycrystalline diamond (PCD) prepared by the high temperature and pressure method often uses Co as a binder, which had a detrimental effect on the cutting performance of PCD, thus Co needed to be removed. However, the removal of Co would cause residual holes and also make the cutting performance of PCD poorer. To address this issue, hot filament chemical vapor deposition (HFCVD) was used. During deposition, the residual holes cannot be filled fully, and Co would diffuse to the interface between CVD diamond coatings and the PCD substrate, which influenced the adhesive strength of the diamond coating with the PCD substrate. In order to investigate the influencing mechanism, both experiments and the density functional theory (DFT) calculations have been employed. The experimental results demonstrate that Co and the holes in the interface would reduce the interfacial binding strength. Further, we built interfacial structures consisting of diamond (100), (110), (111) surfaces and PCD to calculate the corresponding interfacial binding energy, charge density and charge density difference. After contrast, for Co and the holes located on the (110) surface, the corresponding interfacial binding energy was bigger than the others. This means that the corresponding C-C covalent bond was stronger, and the interfacial binding strength was higher. Based on this, conducting cobalt removal pretreatment, optimizing the PCD synthetic process and designing the site of Co can improve the performance of the PCD substrate CVD diamond coating tools.

Review of progress in the materials development of Re, Os, and Ir-based double perovskite oxides

In this review, we examine the latest experimental advances in materials science, focusing primarily on 5d transition metal-based double perovskite oxides, particularly rhenium (Re), osmium (Os), and iridium (Ir). These materials have attracted considerable attention because of their unique properties compared to conventional perovskite oxides, including high-TC ferrimagnetism, half-metallicity, insulating ferromagnetism, polar ferroelectricity, and multipolar magnetism. We have shown through many experiments that the high-temperature and high-pressure synthesis method is effective for introducing 5d transition metals such as Re, Os, and Ir into the B site of perovskite oxides. Here, we mainly discuss the high-pressure synthesis of novel double perovskite oxides and their properties. This process leads to characteristic relativistic effects and properties not observed in conventional perovskites. The adaptable nature of the double perovskite structure allows for significant modification of both A- and B-site elements, resulting in a wide range of physical properties. In this review, we will organize our understanding of Re-, Os-, and Ir-based double perovskites, highlight the influence of crystal structure on various properties, and explore potential applications across multiple technical and scientific domains. The goal is to provide a comprehensive overview that will enhance understanding and facilitate advances in the field of double perovskite materials research.

High-pressure synthesis and magnetic properties of Gd2Rh3Al9 with a distorted honeycomb lattice

This study focuses on exploring new Gd-based intermetallic compounds with honeycomb structures to elucidate intriguing magnetic phenomena, particularly the presence of magnetic skyrmions. The compound Gd2Rh3Al9, synthesized via high-temperature and high-pressure methods, exhibits an orthorhombic structure characterized by a distorted Gd-honeycomb network. Comprehensive investigations of its temperature-dependent behavior in polycrystalline samples reveal sequential antiferromagnetic transitions occurring at T1 = 13.6 K and T2 = 4.1 K. These transitions arise from the antiferromagnetic interaction between the magnetic moments of Gd3+ (S = 7/2) situated within the distorted honeycomb layer. Despite not observing a skyrmion phase in this compound, the data provide valuable insights into the complex behavior of Gd-based intermetallic compounds and their potential as hosts for novel magnetic phases. Further research, particularly using single crystals, is needed to explore the possibility of forming a skyrmion phase in this compound.

A Sterile, Injectable, and Robust Sericin Hydrogel Prepared by Degraded Sericin.

The application of sericin hydrogels is limited mainly due to their poor mechanical strength, tendency to be brittle and inconvenient sterilization. To address these challenges, a sericin hydrogel exhibiting outstanding physical and chemical properties along with cytocompatibility was prepared through crosslinking genipin with degraded sericin extracted from fibroin deficient silkworm cocoons by the high temperature and pressure method. Our reported sericin hydrogels possess good elasticity, injectability, and robust behaviors. The 8% sericin hydrogel can smoothly pass through a 16 G needle. While the 12% sericin hydrogel remains intact until its compression ratio reaches 70%, accompanied by a compression strength of 674 kPa. 12% sericin hydrogel produce a maximum stretch of 740%, with breaking strength and tensile modulus of 375 kPa and 477 kPa respectively. Besides that, the hydrogel system demonstrated remarkable cell-adhesive capabilities, effectively promoting cell attachment and, proliferation. Moreover, the swelling and degradation behaviors of the hydrogels are pH responsiveness. Sericin hydrogel releases drugs in a sustained manner. Furthermore, this study addresses the challenge of sterilizing sericin hydrogels (sterilization will inevitably lead to the destruction of their structures). In addition, it challenges the prior notion that sericin extracted under high temperature and pressure is difficult to directly cross-linked into a stable hydrogel. This developed hydrogel system in this study holds promise to be a new multifunctional platform expanding the application area scope of sericin.

Sample heating above 1400 K in a diamond anvil cell

In high-pressure experimental methods, sample heating in the pressure chamber of a diamond anvil cell is an important topic, and numerous efforts have been made to improve and develop new technologies. In this paper, we propose a new type of internal resistance heating technique, the composite heating gasket, prepared by integrating an annular heater into the sample chamber for direct heating of the sample. As the effective heating area covers the entire pressure chamber wall, a relatively quasi-uniform temperature field is formed within the sample chamber. At the same time, the integration design reduces the risk of diamond oxidation and enables direct measurement of the spectroscopic properties of samples at high temperatures. The preparation of the composite heating gasket is simple and repeatable, and its heating performance is stable at temperatures above 1400 K. When the sample diameter is 210 μm and no thermal insulation is used, the diameter of the temperature zone in which the temperature difference is less than 10 and 20 K exceeds 120 and 170 μm, respectively. The composite heating gasket represents a significant advancement in providing a uniform temperature field for in situ measurements with diamond anvil cells at high pressure and temperature.