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1.
BJU Int ; 2024 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-38817129

RESUMO

OBJECTIVE: To evaluate the effect of a new strategy of transperineal anastomotic urethroplasty (TAU) with proximal transection in treating pelvic fracture urethral injury (PFUI) associated with urethrorectal fistula (URF). PATIENTS AND METHODS: A retrospective review of all patients treated by TAU with proximal transection and fistula repair for PFUI associated with URF was performed between August 2013 and July 2022. Information on demographics, peri-operative variables, and postoperative follow-up outcomes was collected. Successful surgery was defined as restoration of a uniform urethral calibre using flexible cystoscopy (third postoperative month) without strictures or leakage, with no further interventions required. Functional outcomes, including erectile function (assessed using the five-item International Index of Erectile Function) and urinary continence, were assessed. RESULTS: Forty patients diagnosed with PFUI associated with URF and treated by TAU with proximal transection and rectal fistula repair were enrolled. Six patients (15.0%) had a history of failed urethral reconstruction. The mean stenosis length and fistula diameter were 2.9 cm and 1.2 cm, respectively. All patients underwent faecal diversion before urethroplasty. After a median (range) follow-up of 45 (3-115) months, the final success rate was 90.0% (36/40). Postoperative complications included haematoma in three patients, epididymo-orchitis in three, wound infection in one, wound bleeding in one, delayed wound healing in three, and wound numbness in three. The overall incidence of postoperative erectile dysfunction reached 75.0%, with a median (range) score of 9 (0-19). Normal continence was achieved in 31 patients (77.5%). Occasional incontinence without the need for urinal pads occurred in eight patients, whereas one patient required urinal pads. CONCLUSIONS: Transperineal anastomotic urethroplasty with proximal transection is a precise and effective surgical strategy for treating PFUI associated with URF. This strategy ensures a high success rate and improves surgical efficiency.

2.
ACS Appl Mater Interfaces ; 16(12): 15023-15031, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38498850

RESUMO

Interface-influenced crystallization is crucial to understanding the nucleation- and growth-dominated crystallization mechanisms in phase-change materials (PCMs), but little is known. Here, we find that composition vacancy can reduce the interface energy by decreasing the coordinate number (CN) at the interface. Compared to growth-dominated GeTe, nucleation-dominated Ge2Sb2Te5 (GST) exhibits composition vacancies in the (111) interface to saturate or stabilize the Te-terminated plane. Together, the experimental and computational results provide evidence that GST prefers (111) with reduced CN. Furthermore, the (8 - n) bonding rule, rather than CN6, in the nuclei of both GeTe and GST results in lower interface energy, allowing crystallization to be observed at the simulation time in general PCMs. In comparison to GeTe, the reduced CN in the GST nuclei further decreases the interface energy, promoting faster nucleation. Our findings provide an approach to designing ultrafast phase-change memory through vacancy-stabilized interfaces.

3.
Curr Urol ; 18(1): 30-33, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38505155

RESUMO

Objectives: To assess the effect of redo inferior pubectomy on the management of complicated pelvic fracture urethral injury (PFUI) in patients with a history of failed anastomotic urethroplasty. Materials and methods: We retrospectively reviewed all patients receiving redo anastomotic urethroplasty with redo inferior pubectomy for failed PFUI between January 2010 and December 2021. Patients with incomplete data and those who were lost to follow-up were excluded. Successful urethroplasty was defined as the restoration of a uniform urethral caliber without stenosis or leakage and further intervention. Functional results, including erectile function and urinary continence, were evaluated. Descriptive statistical analyses were then performed. Results: Thirty-one patients were included in this study. Among them, concomitant urethrorectal fistula occurred in 2 patients, and concomitant enlarged bladder neck occurred in 1. The stenosis site was the bulbomembranous urethra in 2 patients and the prostatomembranous urethra in 29. The mean length of urethral stenosis in all patients was 3.1 cm (range, 2.0-5.0 cm). After a mean follow-up of 34.6 months, the final success rate was 96.8%. The incidence of erectile dysfunction reached 77.4% (24/31). Normal continence was achieved in 27 (87.1%) patients. One patient developed urinary incontinence of grade II requiring urinary pads because of an enlarged bladder neck. According to the Clavien-Dindo classification, postoperative complications of grade I occurred in 7 patients and grade II in 4. Conclusions: Repeat anastomotic urethroplasty with repeat inferior pubectomy provides reliable success rates for failed PFUI. In complicated cases, it should be known and mastered.

4.
Artigo em Inglês | MEDLINE | ID: mdl-38401081

RESUMO

Objective: To analyze the potential value of paraspinal nerve block (PVB) in percutaneous nephrolithotomy (PCNL) and to compare it with general anesthesia and epidural anesthesia. Methods: 120 patients undergoing PCNL surgery in Shanghai Jiao Tong University Affiliated Sixth People's Hospital from January 2021 to June 2022 were selected and divided into PVB anesthesia group, general anesthesia group, and epidural anesthesia group according to different anesthesia methods, with 40 cases in each group. The anesthesia index (anesthesia operation time, anesthetic effect time, anesthesia time), the vital signs (heart rate, mean arterial pressure), postoperative pain [visual analog scale (VAS)], stress response index (cortisol and noradrenaline), the incidence of adverse reactions (nausea and vomiting, lethargy, dizziness, skin itching, bradycardia) were compared among the three groups. Results: The operation time of the anesthesia in the PVB anesthesia group was 5.72±1.25, which was significantly lower than that in the the general (7.95±1.15) and epidural anesthesia groups(8.23±1.43), and the differences were statistically significant (P = .000). The time of onset of anesthesia in the PVB anesthesia group was 6.63±1.87, which was significantly lower than that in the the general (9.84±2.41) and epidural anesthesia groups(10.14±2.89), and the differences were statistically significant (P = .000).The heart rate during percutaneous puncture and intraoperative lithotripsy in the PVB anesthesia group was statistically lower than in the general and epidural anesthesia groups (P < .05). The mean arterial pressure 20 minutes after anesthesia and at the end of operation in the PVB anesthesia group was higher than that in the general anesthesia group, and the mean arterial pressure during percutaneous puncture and intraoperative lithotomy was lower than that in the general anesthesia group (P < .05). The VAS scores of the PVB anesthesia group at 2, 6, 12, 24, and 48 hours after the operation were lower than those of general and epidural anesthesia groups (P < .05). The incidence of adverse reactions was 5.00% (2/40) in the PVB anesthesia group and 35.00% (14/40) in the general anesthesia group, which was lower than that of 27.50% (11/40) in the epidural anesthesia group. (P < .05). Conclusion: The potential value of PVB in PCNL is high is better than that of general anesthesia and epidural anesthesia, anesthesia can shorten operation time and work time, extend the time of anesthesia to maintain, and be helpful to the intraoperative vital signs in patients with stable, mild postoperative pain and stress, low incidence of adverse reactions, efficacy and safety are good, can be introduced.

5.
Adv Sci (Weinh) ; 11(9): e2301021, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38133500

RESUMO

The disorder-to-order (crystallization) process in phase-change materials determines the speed and storage polymorphism of phase-change memory devices. Only by clarifying the fine-structure variation can the devices be insightfully designed, and encode and store information. As essential phase-change parent materials, the crystallized Sb-Te binary system is generally considered to have the cationic/anionic site occupied by Sb/Te atoms. Here, direct atomic identification and simulation demonstrate that the ultrafast crystallization speed of Sb-Te materials is due to the random nature of lattice site occupation by different classes of atoms with the resulting octahedral motifs having high similarity to the amorphous state. It is further proved that after atomic ordering with disordered chemical occupation, chemical ordering takes place, which results in different storage states with different resistance values. These new insights into the complicated route from disorder to order will play an essential role in designing neuromorphic devices with varying polymorphisms.

6.
Front Neurol ; 14: 1172695, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37360354

RESUMO

Background: Rosai-Dorfman-Destombes disease (RDD) was first described in 1965 as a benign histiocytic proliferative disorder of unknown cause. Cases of RDD limited to cutaneous tissue have been reported over the past few decades, but single cutaneous RDD of the scalp is rare. Case presentation: We report a 31-year-old male with a lump on the parietal scalp without extranodal lesion lasting 1 month with gradual enlargement. The surgical incision ruptured with purulent after the first resection. Then the patient was treated with plastic surgery after disinfection and antibiotic treatment. Finally, he recovered well and discharged after 20 days. Conclusions: RDD of the scalp is rare. Surgical incision can cure the lesion but it may become infected because of increased lymphocytic infiltration. Early diagnosis and differential diagnosis of RDD are necessary. For treatment, individualized therapy is critical to patient prognosis.

7.
J Craniofac Surg ; 34(5): 1559-1562, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37226294

RESUMO

This study aimed to compare the outcomes of trigeminal nerve isolation (TNI) with conventional microvascular decompression (CMVD) in cases of trigeminal neuralgia (TN). We retrospectively reviewed 143 TN cases who underwent microvascular decompression from January 2017 to January 2020. The surgical management of TNI or CMVD in all patients was randomized. The cases were divided into two groups, one group underwent a TNI and the other one received CMVD. The general data, postoperative outcomes, and complications were reviewed retrospectively. Cases with a narrow cistern of cerebellopontine, short trigeminal nerve root, and arachnoid adhesion were defined as difficult cases. All of the cases were followed up for at least 1 year. Surgical outcomes were assessed and compared between the two groups. In results, we found no significant differences in the general data, duration of hospitalization and blood loss between the two procedures. However, of the 143 cases, 12 cases (17.1%) recurred after surgery in the CMVD group, and four cases (5.5%) recurred after TNI operation. The rates of pain relief were 69 (94.5%) in the CMVD group, and 58 (82.9%) for TNI ( P =0.027). In the TNI group, there was only one difficult case among four no pain-relief cases, while in the CMVD group, 10 difficult cases were found among the 12 no pain-relief cases ( P =0.008). In conclusion, the TNI technique is more effective than the CMVD procedure and could also be performed on patients with classical TN. Future double-blind and randomized controlled trials are necessary to confirm this result.


Assuntos
Cirurgia de Descompressão Microvascular , Neuralgia do Trigêmeo , Humanos , Cirurgia de Descompressão Microvascular/métodos , Manejo da Dor/métodos , Estudos Retrospectivos , Resultado do Tratamento , Nervo Trigêmeo/cirurgia , Neuralgia do Trigêmeo/complicações
8.
Nanomaterials (Basel) ; 13(4)2023 Feb 09.
Artigo em Inglês | MEDLINE | ID: mdl-36839039

RESUMO

As a new generation of non-volatile memory, phase change random access memory (PCRAM) has the potential to fill the hierarchical gap between DRAM and NAND FLASH in computer storage. Sb2Te3, one of the candidate materials for high-speed PCRAM, has high crystallization speed and poor thermal stability. In this work, we investigated the effect of carbon doping on Sb2Te3. It was found that the FCC phase of C-doped Sb2Te3 appeared at 200 °C and began to transform into the HEX phase at 25 °C, which is different from the previous reports where no FCC phase was observed in C-Sb2Te3. Based on the experimental observation and first-principles density functional theory calculation, it is found that the formation energy of FCC-Sb2Te3 structure decreases gradually with the increase in C doping concentration. Moreover, doped C atoms tend to form C molecular clusters in sp2 hybridization at the grain boundary of Sb2Te3, which is similar to the layered structure of graphite. And after doping C atoms, the thermal stability of Sb2Te3 is improved. We have fabricated the PCRAM device cell array of a C-Sb2Te3 alloy, which has an operating speed of 5 ns, a high thermal stability (10-year data retention temperature 138.1 °C), a low device power consumption (0.57 pJ), a continuously adjustable resistance value, and a very low resistance drift coefficient.

9.
Adv Mater ; 35(11): e2208065, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36719053

RESUMO

Phase-change memory (PCM) is one of the most promising candidates for next-generation data-storage technology, the programming speed of which has enhanced within a timescale from milliseconds to sub-nanosecond (≈500 ps) through decades of effort. As the potential applications of PCM strongly depend on the switching speed, namely, the time required for the recrystallization of amorphous chalcogenide media, the finding of the ultimate crystallization speed is of great importance both theoretically and practically. In this work, through systematic analysis of discovered phase-change materials and ab initio molecular dynamics simulations, elemental Sb-based PCM is predicted to have a superfast crystallization speed. Indeed, such cells experimentally present extremely fast crystallization speeds within 360 ps. Remarkably, the recrystallization process is further sped up as the device shrinks, and a record-fast crystallization speed of only 242 ps is achieved in 60 nm-size devices. These findings open opportunities for dynamic random-access memory (DRAM)-like and even cache-like PCM using appropriate storage materials.

10.
Nanotechnology ; 34(15)2023 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-36652702

RESUMO

Ge2Sb2Te5(GST) is the most widely used matrix material in phase change random access memory (PCRAM). In practical PCRAM device, the formed large hexagonal phase in GST material is not preferred, especially when the size of storage architecture is continually scaling down. In this report, with the aid of spherical-aberration corrected transmission electron microscopy (Cs-TEM), the grain growth behavior during thein situheating process in GST alloy is investigated. Generally, the metastable face-centered-cubic (f-) grain tends to grow up with increasing temperature. However, a part of f-phase nanograins with {111} surface plane does not grow very obviously. Thus, the grain size distribution at high temperature shows a large average grain size as well as a large standard deviation. When the vacancy ordering layers forms at the grain boundary area in the nanograins, which is parallel to {111} surface plane, it could stabilize and refine these f-phase grains. By elaborating the relationship between the grain growth and the vacancy ordering process in GST, this work offers a new perspective for the grain refinement in GST-based PCRAM devices.

11.
Front Neurol ; 14: 1336273, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38292034

RESUMO

The rhomboid lip (RL) is a layer of neural tissue that extends outside the fourth ventricle and is connected to the lateral recess of the fourth ventricle. Although this anatomical structure has been rigorously studied, it is often overlooked in microvascular decompression (MVD) surgery. In this report, we present two cases, one of hemifacial spasm (HFS) and one of glossopharyngeal neuralgia (GPN), in which a large RL was observed during surgery. We found that a large RL is easily confused with arachnoid cysts, and accurate identification and dissection are important to protect the lower cranial nerves.

12.
Adv Sci (Weinh) ; 9(25): e2202222, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36062987

RESUMO

Nonvolatile phase-change random access memory (PCRAM) is regarded as one of the promising candidates for emerging mass storage in the era of Big Data. However, relatively high programming energy hurdles the further reduction of power consumption in PCRAM. Utilizing narrow edge-contact of graphene can effectively reduce the active volume of phase change material in each cell, and therefore realize low-power operation. Here, it demonstrates that the power consumption can be reduced to ≈53.7 fJ in a cell with ≈3 nm-wide graphene nanoribbon (GNR) as edge-contact, whose cross-sectional area is only ≈1 nm2 . It is found that the polarity of the bias pulse determines its cycle endurance in the asymmetric structure. If a positive bias is applied to the graphene electrode, the endurance can be extended at least one order longer than the case with a reversal of polarity. In addition, the introduction of the hexagonal boron nitride (h-BN) multilayer leads to a low resistance drift and a high programming speed in a memory cell. The work represents a great technological advance for the low-power PCRAM and can benefit in-memory computing in the future.

13.
Crit Rev Eukaryot Gene Expr ; 32(7): 67-76, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36004696

RESUMO

Tripartite motif-containing protein 11 (TRIM11) and family with sequence similarity 46B (FAM46B) have been demonstrated to play roles in prostate cancer development, but their function in paclitaxel resistance remains unclear. The role of TRIM11 and FAM46B in paclitaxel resistance in prostate cancer was estimated. The paclitaxel-resistant cells were established with gradually increasing concentrations of paclitaxel in prostate cancer cells. The sensitivity to paclitaxel of established cells was assessed by the value of the median inhibitory concentration in the presence of 0-1000 nM paclitaxel. The expression level of TRIM11 and FAM46B was evaluated by real-time quantitative polymerase chain reaction. The proliferation, migration, and invasion of established cells were evaluated by CCK8 and Tran-swell assay. TRIM11 was upregulated in paclitaxel-resistant cells and promoted the proliferation, migration, and invasion of established cells. The significant downregulation of FAM46B was observed in paclitaxel-resistant cells. Although the overexpression of FAM46B suppressed the viability and metastasis of paclitaxel-resistant cells, which was reversed by the upregulation of TRIM11. Both the knockdown of TRIM11 and overexpression of FAM46B could enhance paclitaxel sensitivity of established resistant cells. The promoted effect of FAM46B overexpression was alleviated by the elevation of TRIM11. TRIM11 could improve the sensitivity to paclitaxel of resistant prostate cancer cells via regulating FAM46B.


Assuntos
Paclitaxel , Neoplasias da Próstata , Linhagem Celular Tumoral , Proliferação de Células , Resistencia a Medicamentos Antineoplásicos/genética , Humanos , Masculino , Paclitaxel/farmacologia , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Proteínas com Motivo Tripartido/genética , Ubiquitina-Proteína Ligases/genética
14.
Nat Commun ; 12(1): 6473, 2021 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-34753920

RESUMO

While alloy design has practically shown an efficient strategy to mediate two seemingly conflicted performances of writing speed and data retention in phase-change memory, the detailed kinetic pathway of alloy-tuned crystallization is still unclear. Here, we propose hierarchical melt and coordinate bond strategies to solve them, where the former stabilizes a medium-range crystal-like region and the latter provides a rule to stabilize amorphous. The Er0.52Sb2Te3 compound we designed achieves writing speed of 3.2 ns and ten-year data retention of 161 °C. We provide a direct atomic-level evidence that two neighbor Er atoms stabilize a medium-range crystal-like region, acting as a precursor to accelerate crystallization; meanwhile, the stabilized amorphous originates from the formation of coordinate bonds by sharing lone-pair electrons of chalcogenide atoms with the empty 5d orbitals of Er atoms. The two rules pave the way for the development of storage-class memory with comprehensive performance to achieve next technological node.

15.
Micromachines (Basel) ; 11(6)2020 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-32545476

RESUMO

Depositing platinum (Pt) interconnectors during the sample preparation process via a focused ion beam (FIB) system is an inescapable procedure for in situ transmission electron microscopy (TEM) investigations. To achieve good electrical contact and avoid irreversible damage in practical samples, the microscopic evolution mechanism of FIB-deposited Pt interconnectors need a more comprehensive understanding, though it is known that its resistivity could be affected by thermal annealing. In this work, an electron-beam FIB-deposited Pt interconnector was studied by advanced spherical aberration (Cs)-corrected TEM combined with an in situ heating and biasing system to clarify the relationship of microscopic evolution to resistivity variation. During the heating process, the Pt interconnector underwent crystallization, organic matter decomposition, Pt nanocrystal growth, grain connection, and conductive path formation, which are combined actions to cause several orders of magnitude of resistivity reduction. The comprehensive understanding of the microscopic evolution of FIB-deposited Pt material is beneficial, not only for optimizing the resistance performance of Pt as an interconnector, but also for understanding the role of C impurities with metal materials. For the purpose of wiring, annealed electron-beam (EB)-deposited Pt material can be recommended for use as an interconnector in devices for research purposes.

16.
Drug Des Devel Ther ; 14: 1547-1559, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32368013

RESUMO

PURPOSE: The role of angiotensin-converting enzyme 2 (ACE2) in silicosis remains unknown, although previous studies have suggested that ACE2 may be beneficial. We, therefore, investigated the effect of ACE2 on silicosis, particularly with regard to its role in regulating the epithelial-mesenchymal transition (EMT) induced by silica, with the aim to uncover a new potential target for the treatment of pulmonary fibrosis. MATERIALS AND METHODS: We employed wild-type mice treated with diminazene aceturate (DIZE, an ACE2 activator, 15 mg/kg/day for 4 weeks), hACE2-transgenic mice (overexpress the ACE2 gene), and the mouse lung type II epithelial cell line treated with DIZE (10-7 M for 48 h) or angiotensin-(1-7) [Ang-(1-7)] (10-4 M for 48 h), following induced fibrotic responses to determine the protective potential of ACE2. Silicosis models were established by orotracheal instillation of SiO2 (2.5 mg/mouse). Immunostaining was used to determine α-smooth muscle actin (α-SMA) expression. The activities of angiotensin-converting enzyme (ACE) and ACE2 and the levels of angiotensin II (Ang II) and Ang-(1-7) were detected by enzyme-linked immunosorbent assay. The mRNA expression of ACE and ACE2, and protein expression of the renin-angiotensin system (RAS) components and EMT indicators were studied by qRT-PCR and Western blot, respectively. RESULTS: DIZE treatment and overexpression of ACE2 markedly inhibited the formation of silica-induced lung fibrosis and increased the level of E-cadherin, with concomitant downregulation of pro-collagen, vimentin, and α-SMA via RAS signaling. Furthermore, DIZE and Ang-(1-7) attenuated the EMT and collagen deposition induced by silica in MLE-12 cells. Moreover, these effects were abrogated by MLN-4760 (a specific ACE2 inhibitor) and A779 (a specific Mas receptor blocker). CONCLUSION: The overexpression of ACE2 and treatment with DIZE can ameliorate EMT in silicotic mice via activation of the ACE2-Ang-(1-7)-Mas receptor axis, and these changes are accompanied by suppression of the ACE-Ang II-AT1 receptor axis.


Assuntos
Enzima de Conversão de Angiotensina 2/metabolismo , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Dióxido de Silício/farmacologia , Silicose/metabolismo , Enzima de Conversão de Angiotensina 2/genética , Animais , Linhagem Celular , Relação Dose-Resposta a Droga , Masculino , Camundongos , Camundongos Endogâmicos ICR , Relação Estrutura-Atividade
17.
ACS Appl Mater Interfaces ; 12(20): 23051-23059, 2020 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-32340441

RESUMO

Carbon (C)-doped Ge2Sb2Te5 material is a potential candidate in phase change random access memory (PCRAM) because of its superb thermal stability and ultrahigh cycle endurance. Unfortunately, the role and distribution evolution of C-dopant is still not fully understood, especially in practical industrial devices. In this report, with the aid of advanced spherical aberration corrected transmission electron microscopy, the mechanism of microstructure evolution manipulated by C-dopant is clearly defined. The grain-inner C atoms distinctly increase cationic migration energy barriers, which is the fundamental reason for promoting the thermal stability of metastable face-centered-cubic phase and postponing its transition to the hexagonal structure. By current pulses stimulation, the stochastic grain-outer C clusters tend to aggregate in the active area by breaking C-Ge bonding; thus, grain growth and elemental segregation are effectively suppressed to improve device reliability, for example, lower SET resistance, shorter SET time, and enlarged RESET/SET ratio. In short, the visual distribution variations of C-dopant can manipulate the performance of the PCRAM device, having much broader implications for optimizing its microstructure transition and understanding C-doped material system.

18.
ACS Appl Mater Interfaces ; 11(49): 45885-45891, 2019 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-31749358

RESUMO

A multilevel phase-change memory device was successfully designed, which was fabricated using a Ge40Te60/Cr superlattice-like (SLL) structure. In the SLL films, a two-step phase change process is observed at elevated temperatures, which reveals the crystallization of Ge40Te60 (GT) and an interface-dominated formation of Cr2Ge2Te6 (CrGT). The bonding of Cr-Te and Ge-Ge is accompanied by the breaking of a Ge-Te bond, which is mainly in the Ge-rich GeTe4-nGen units. The formation of CrGT is related to the breaking apart of the edge-sharing octahedron in GT and Cr replacement at Ge sites. The crystalline GT acts as the crystallization precursors in the formation of the CrGT phase. The stable reversible two-step phase change can guarantee the reliability of the multilevel storage. The present work may shed light on the possible mechanism of the CrGT phase transition-based interfacial dynamic process. The designed multiple crystallization system demonstrates a potential for multilevel storage.

19.
Nat Commun ; 10(1): 3525, 2019 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-31388013

RESUMO

Doping is indispensable to tailor phase-change materials (PCM) in optical and electronic data storage. Very few experimental studies, however, have provided quantitative information on the distribution of dopants on the atomic-scale. Here, we present atom-resolved images of Ag and In dopants in Sb2Te-based (AIST) PCM using electron microscopy and atom-probe tomography. Combing these with DFT calculations and chemical-bonding analysis, we unambiguously determine the dopants' role upon recrystallization. Composition profiles corroborate the substitution of Sb by In and Ag, and the segregation of excessive Ag into grain boundaries. While In is bonded covalently to neighboring Te, Ag binds ionically. Moreover, In doping accelerates the crystallization and hence operation while Ag doping limits the random diffusion of In atoms and enhances the thermal stability of the amorphous phase.

20.
ACS Appl Mater Interfaces ; 11(11): 10848-10855, 2019 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-30810295

RESUMO

Phase change memory (PCM) with advantages of high operation speed, multilevel storage capability, spiking-time-dependent plasticity, etc., has wide application scenarios in both Von Neumann systems and neuromorphic systems. In the automotive application, intelligent system not only needs high efficiency to handle massive data processing but also good robustness to retain the existing data against high working temperature. In this work, Sc-doped GeTe is developed for PCM, which has achieved 120 °C data retention for 10 years, 6 ns operation speed, and 7 nJ low power consumption. The high data retention is attributed to the high coordination number of Sc and its strong bonds with Te atoms in the amorphous phase, which enhances the robustness of the atomic matrices. Sc-centered octahedrons in amorphous state provide a nucleation center, leading to fast crystallization. In the crystalline phase, Sc atoms occupy Ge vacancies to form a homogenous GeTe-like rhombohedral phase. The strong covalent-like Sc-Te bonds weaken the neighboring Ge-Te bonds, lowering energy for melting. Together with the increased energy efficiency originated from confined grain size, the reduced power consumption has been achieved. The improvements in data retention, speed, and power efficiency have made Sc-doped GeTe a promising candidate for high-performance automobile electronics application.

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