Modification of ultrananocrystalline diamond film microstructure via Fe-coating and annealing for enhancement of electron field emission properties

[[abstract]]The interaction between Fe-coatings and ultrananocrystalline diamond (UNCD) films during annealing was investigated in detail using transmission electron microscopy. The thin Fe-coating first formed nanosized Fe-clusters and then catalytically dissociated the diamond, re-precipitating carbon to form nanosized graphite clusters. These clusters formed conducting networks that facilitated electron transport and greatly improved the electron field emission (EFE) properties of the UNCD films. The extent of enhancement varied markedly with annealing temperature and atmosphere. For H2-annealed films, EFE behavior was optimized by annealing at 900 °C. EFE was turned on at (E0)H2 = 1.2 V/μm, attaining EFE current density of (Je)H2 = 772.0 μA/cm2 at an applied field of 8.8 V/mm. These characteristics were superior to those of UNCD films NH3-annealed at 850 °C. The inferior EFE properties for the NH3-annealed samples were attributed to reaction of NH3 with the hydrocarbon phase that encapsulated the nanosized diamond grains, hindering Fe–diamond interaction.[[booktype]]紙

Bias-enhanced nucleation and growth processes for improving the electron field emission properties of diamond films

[[abstract]]The evolution of diamond films in bias-enhanced-nucleation (BEN) and bias-enhanced-growth (BEG) processes was systematically investigated. While the BEN process can efficiently form diamond nuclei on the Si substrates, BEG with large enough applied field (> –400 V) and for sufficiently long periods (>60 min) was needed to develop proper granular structure for the diamond films so as to enhance the electron field emission (EFE) properties of the films. For the films BEG under -400 V for 60 min (after BEN for 10 min), the EFE process can be turned on at a field as small as 3.6 V/μm, attaining a EFE current density as large as 325 μA/cm2 at an applied field of 15 V/μm. Such an EFE behavior is even better than that of the ultrananocrystalline diamond films grown in CH4/Ar plasma. Transmission electron microscopic examination reveals that the prime factor enhancing the EFE properties of these films is the induction of the nano-graphite filaments along the thickness of the films that facilitates the transport of electrons through the films.[[journaltype]]國外[[ispeerreviewed]]Y[[booktype]]紙本[[countrycodes]]US

A Local Diagnosis Algorithm for Hypercube-like Networks under the BGM Diagnosis Model

System diagnosis is process of identifying faulty nodes in a system. An efficient diagnosis is crucial for a multiprocessor system. The BGM diagnosis model is a modification of the PMC diagnosis model, which is a test-based diagnosis. In this paper, we present a specific structure and propose an algorithm for diagnosing a node in a system under the BGM model. We also give a polynomial-time algorithm that a node in a hypercube-like network can be diagnosed correctly in three test rounds under the BGM diagnosis model

Microstructure evolution and the modification of the electron field emission properties of diamond films by gigaelectron volt Au-ion irradiation

[[abstract]]The effect of 2.245 GeV Au-ion irradiation and post-annealing processes on the microstructure and electron field emission (EFE) properties of diamond films was investigated. For the microcrystalline diamond (MCD) films, Au-ion irradiation with a fluence of approximately 8.4×1013 ions/cm2 almost completely suppressed the EFE properties of the films. Post-annealing the Au-ion irradiated MCD films at 1000°C for 1 h effectively restored these properties. In contrast, for ultra-nanocrystalline diamond (UNCD) films, the Au-ion irradiation induced a large improvement in the EFE properties, and the post-annealing process slightly degraded the EFE properties of the films. The resulting EFE behavior was still better than that of pristine UNCD films. TEM examination indicated that the difference in Au-ion irradiation/post-annealing effects on the EFE properties of the MCD and UNCD films is closely related to the different phase transformation process involved. This difference is dependent on the different granular structures of these films. The MCD films with large-grain microstructure contain very few grain boundaries of negligible thickness, whereas the UNCD films with ultra-small-grain granular structure contain abundant grain boundaries of considerable thickness. Au-ion irradiation disintegrated the large grains in the MCD films into small diamond clusters embedded in an amorphous carbon (a-C) matrix that suppressed the EFE properties of the MCD films. In contrast, the Au-ion irradiation insignificantly altered the crystallinity of the grains of the UNCD films but transformed the grain boundary phase into nano-graphite, enhancing the EFE properties. The post-annealing process recrystallized the residual a-C phase into nano-graphites for both films.[[incitationindex]]SCI[[booktype]]電子

Screening Spin Lattice Interaction Using Deep Learning Approach

Atomic simulations hold significant value in clarifying crucial matters such as phase transitions and energy transport in materials science. Their success stems from the presence of potential energy functions capable of accurately depicting the relationship between system energy and lattice changes. In magnetic materials, two atomic scale degrees of freedom come into play: the lattice and the magnetic moment. Nonetheless, precisely portraying the interaction energy and its impact on lattice and spin-driving forces, such as atomic force and magnetic torque, remains a formidable task in the computational domain. Consequently, there is no atomic-scale approach capable of elucidating the evolution of lattice and spin at the same time in magnetic materials. Addressing this knowledge deficit, we present DeepSPIN, a versatile approach that generates high-precision predictive models of energy, atomic forces, and magnetic torque in magnetic systems. This is achieved by integrating first-principles calculations of magnetic excited states with advanced deep learning techniques via active learning. We thoroughly explore the methodology, accuracy, and scalability of our proposed model in this paper. Our technique adeptly connects first-principles computations and atomic-scale simulations of magnetic materials. This synergy presents opportunities to utilize these calculations in devising and tackling theoretical and practical obstacles concerning magnetic materials.Comment: 8 pages, 4 figure

Functional Biomaterials Modulate Macrophage in the Tumour Micro-environment

The inflammation response requires the cooperation of macrophages with immune cell function and active factors, such as cytokines and chemokines. Through this response, these factors are involved in the immune response to affect physiological activities. Macrophages can be categorized into two types: ‘M1’ and ‘M2’. M1 macrophages destroy the pathogen through phagocytosis activation, ROS production, and antigen-presenting, among other functions. M2 macrophages release cellular factors for tissue recovery, growth, and angiogenesis. Studies have determined that tumour tissue presents with numerous macrophages, termed tumour-associated macrophages. Tumour cells and peripheral stromal cells stimulate the tumour associated with macrophages (M2) to produce factors that regulate angiogenesis. Modulating the balance of the M1 and M2 function has already gained interest as a potentially valuable immune disease therapy. However, applications of the immunotherapy in clinical treatments are still not clear with regard to the cellular working mechanism. Therefore, we summarized the functions of common biomaterials involved in the modulation of the macrophage

Cetuximab and Cisplatin Show Different Combination Effect in Nasopharyngeal Carcinoma Cells Lines via Inactivation of EGFR/AKT Signaling Pathway

Nasopharyngeal carcinoma (NPC) is a common malignant cancer in South China. Cisplatin is a classical chemotherapeutic employed for NPC treatment. Despite the use of cisplatin-based concurrent chemoradiotherapy, distant failure still confuses clinicians and the outcome of metastatic NPC remains disappointing. Hence, a potent systemic therapy is needed for this cancer. Epidermal growth factor receptor (EGFR) represents a promising new therapeutic target in cancer. We predicted that combining the conventional cytotoxic drug cisplatin with the novel molecular-targeted agent cetuximab demonstrates a strong antitumor effect on NPC cells. In this study, we selected HNE1 and CNE2 cells, which have been proved to possess different EGFR expression levels, to validate our conjecture. The two-drug regimen showed a significant synergistic effect in HNE1 cells but an additive effect in CNE2 cells. Our results showed that cisplatin-induced apoptosis was significantly enhanced by cetuximab in the high EGFR-expressing HNE1 cells but not in CNE2 cells. Further molecular mechanism study indicated that the EGFR/AKT pathway may play an important role in cell apoptosis via the mitochondrial-mediated intrinsic pathway and lead to the different antitumor effects of this two-drug regimen between HNE1 and CNE2 cells. Thus, the regimen may be applied in personalized NPC treatments