Search

We report on the new Ruddlesden-Popper (RP) oxyfluoride La2NiO2.5F3 containing an unprecedented high amount of fluorine and Ni2+. This oxyfluoride was prepared by topochemical low-temperature fluorination of La2NiO4, which was obtained by a soft chemistry synthesis, with poly(vinylidene difluoride) (PVDF) as fluorinating agent. La2NiO2.5F3 is the first n = 1 RP compound crystallizing in the tetragonal space group P42/nnm (a = 5.7297(6) A and c = 13.0106(2) A). The crystal structure shows a unique tilting scheme of the NiO4F2 octahedra that has so far been only theoretically predicted. Combined neutron and X-ray powder diffraction experiments together with bond-valence-sum and DFT+U calculations reveal an unusual anion ordering with fluoride being located on the apical anion sites of the NiO4F2 octahedra. Excess fluorine ions were found to populate two of the four interstitial anion sites in an ordered fashion. A third interstitial anion position is occupied by oxygen ions while the fourth site remains unoccupied. This hitherto unobserved ordering scenario in RP oxyfluorides promotes a strong layerwise alternating tilting of the NiO4F2 octahedra. Magnetic measurements show strong antiferromagnetic interactions with a high Neel temperature of about 225 K and a pronounced ZFC/FC splitting most likely as the result of a small ferromagnetic moment arising from spin canting. The electronic structure was characterized by DFT and UV-vis spectroscopy, and a strong increase of Eg was found compared to La2NiO4 (3.4 eV vs 1.3 eV).

Enhancer of zeste homolog 2 (EZH2) is a histone methyltransferase involved in cell proliferation, invasion, angiogenesis, and metastasis in various cancers, including hepatocellular carcinoma (HCC). However, the role and molecular mechanisms of EZH2 in HCC radiosensitivity remain unclear. Here, we show that EZH2 is upregulated in HCC cells and the aberrantly overexpressed EZH2 is associated with the poor prognosis of HCC patients. Using miRNA databases, we identified miR-138-5p as a regulator of EZH2. We also found that miR-138-5p was suppressed by EZH2-induced H3K27me3 in HCC cell lines. MiR-138-5p overexpression and EZH2 knockdown enhanced cellular radiosensitivity while inhibiting cell migration, invasion, and epithelial-mesenchymal transition (EMT). Analysis of RNA-seq datasets revealed that the hypoxia-inducible factor-1 (HIF-1) signaling pathway was the main enrichment pathway for differential genes after miR-138-5p overexpression or EZH2 knockdown. Expression level of HIF-1α was significantly suppressed after miR-138-5p overexpression or silencing of EZH2. HIF-1α silencing mitigated resistance of HCC cells and inhibited EMT. This study establishes the EZH2/miR-138-5p/HIF-1α as a potential therapeutic target for sensitizing HCC to radiotherapy.

Perovskite solar devices are nowadays the fastest advancing photovoltaic technology. Their large-scale application is however restrained by instability and toxicity issues. Alloying is a promising way to stabilize perovskites, optimizing at the same time their absorption and charge-transport properties. We perform an extensive computational study of the thermodynamic stability and electronic properties of oxynitride, oxyfluoride and nitrofluoride perovskites. We consider quaternary stoichiometries of the type ABX2Y, where A and B are any elements of the periodic table and X and Y are nitrogen, oxygen, or fluorine. As a starting point we explore the composition space using a simple five-atom perovskite unit cell. We then filter the candidate compositions according to their distance to the convex hull of thermodynamic stability. For the most stable systems, we then investigate other prototype structures, including more complex perovskite phases that allow for octahedral distortions, and a few non-perovskite geometries. Furthermore, for some paradigmatic cases, we study the effect of disorder by exhaustive enumeration of all possible disordered stoichiometric phases with up to 20 atoms in the unit cell. Our calculations are in very good agreement with data for experimentally known mixed anionic compounds, and predict a series of novel stable (perovskite and non-perovskite) oxynitride and oxyfluoride phases, including some with unexpected chemical composition, and one single nitrofluoride compound. Finally, we calculate and discuss the electronic properties of these compounds and their potential for application as photovoltaic absorbers.

Cs2AgBiBr6 double perovskites are intensely investigated as lead-free, stable alternatives to organic lead halide perovskites. In this contribution, we revise the vibrational modes of Cs2AgBiBr6 and show that Raman spectroscopy is well suited for the detection of common secondary phases such as Cs3Bi2Br9. The combined Raman analysis at pre-, near- and non-resonant conditions allows us to extract the four vibrational modes of Cs2AgBiBr6 to unprecedented detail, the most intense one at 177.3 cm-1. The experimental results are in good agreement with theoretical density functional theory calculations. In addition, we monitor the decomposition of Cs2AgBiBr6 into Cs3Bi2Br9 at temperatures above 255 °C.

Platelet-derived growth receptor α (PDGFRα) is a key factor in many pathophysiological processes. The expression level of PDGFRα is significantly elevated in the early stage of liver development and maintained at a lower level in adult normal livers. In this study, we constructed a liver-specific PDGFRαD842 mutant transgenic (TG) mice model to explore the effect of continuous activation of PDGFRα on liver regeneration and hepatocarcinogenesis. 14-day-old TG and wild-type (WT) mice were intraperitoneally injected with diethylnitrosamine (DEN) at a dose of 25 μg/g body weight. Two-month-old male TG and WT mice were subjected to partial hepatectomy (PH). The liver tissues were collected for further analysis at different time points. Overexpression of PDGFRα D842V and its target genes, Akt, c-myc and cyclin D1 in hepatocytes with no overt phenotype versus WT mice were compared. Unexpectedly, a dramatic decrease in hepatocyte proliferation was noted after PH in TG versus WT mice, possibly due to the downregulation of hepatocyte growth factor receptor (MET) and epidermal growth factor receptor (EGFR). No TG mice developed HCC spontaneously after 14 months follow-up. However, TG mice were more resistant to DEN-induced hapatocarcinogenesis at 6, 10, and 12 months of age, showing delayed hepatocyte proliferation and apoptosis, lower tumor incidence, smaller size and fewer number, compared with age-matched WTs, partially through downregulation of MET and EGFR. In conclusion, continuous activation of PDGFRα signaling by expression of PDGFRα D842V does not promote, but inhibit hepatic regeneration and hepatocarcinogenesis, possibly through compensatory downregulation of MET and EGFR.

Garnets, known since the early stages of human civilization, have found important applications in modern technologies including magnetorestriction, spintronics, lithium batteries, etc. The overwhelming majority of experimentally known garnets are oxides, while explorations (experimental or theoretical) for the rest of the chemical space have been limited in scope. A key issue is that the garnet structure has a large primitive unit cell, requiring an enormous amount of computational resources. To perform a comprehensive search of the complete chemical space for new garnets,we combine recent progress in graph neural networks with high-throughput calculations. We apply the machine learning model to identify the potential (meta-)stable garnet systems before systematic density-functional calculations to validate the predictions. In this way, we discover more than 600 ternary garnets with distances to the convex hull below 100~meV/atom with a variety of physical and chemical properties. This includes sulfide, nitride and halide garnets. For these, we analyze the electronic structure and discuss the connection between the value of the electronic band gap and charge balance.

We present a symmetry-based systematic approach to explore the structural and compositional richness of two-dimensional materials. We use a ‘combinatorial engine’ that constructs candidate compounds by occupying all possible Wyckoff positions for a certain space group with combinations of chemical elements. These combinations are restricted by imposing charge neutrality and the Pauling test for electronegativities. The structures are then pre-optimized with a specially crafted universal neural-network force-field, before a final step of geometry optimization using density-functional theory is performed. In this way we unveil an unprecedented variety of two-dimensional materials, covering the whole periodic table in more than 30 different stoichiometries of form A n B m or A n B m C k . Among the discovered structures, we find examples that can be built by decorating nearly all Platonic and Archimedean tessellations as well as their dual Laves or Catalan tilings. We also obtain a rich, and unexpected, polymorphism for some specific compounds. We further accelerate the exploration of the chemical space of two-dimensional materials by employing machine-learning-accelerated prototype search, based on the structural types discovered in the systematic search. In total, we obtain around 6500 compounds, not present in previous available databases of 2D materials, with a distance to the convex hull of thermodynamic stability smaller than 250 meV/atom.

We report on the new Ruddlesden-Popper (RP) oxyfluoride La

Purpose Outbreaks of infection due to carbapenem-resistant Enterobacterales (CRE), including New Delhi metallo-β-lactamase (NDM)-producing Escherichia coli, have been increasingly reported worldwide, primarily in adults and rarely in children. The goal of this study was to characterize an outbreak of infection caused by NDM-5-producing E. coli in a children's hospital in China. Methods A total of 86 CRE isolates were collected from 85 hospitalized children between June 2017 and May 2018. These isolates were subjected to multiple phenotypic and molecular tests, including in vitro antimicrobial susceptibility testing, PCR, pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and whole-genome sequencing (WGS). Results Among the 86 CRE isolates, we identified 9 NDM-5-producing E. coli isolates, with 5 of them sharing the same PFGE pattern, same MLST type (ST410), same plasmid replicon type (IncFII), and nearly the same set of additional resistance genes. All 9 isolates were resistant to most antimicrobial agents, including carbapenems, cephalosporins, and levofloxacin, while being sensitive to trimethoprim/sulfamethoxazole, amikacin, tigecycline, and colistin. According to the clinical background, all 9 isolates were collected in a period of < 3 months from infants among whom there was overlap in the time of hospitalization. None of them had a travel history. Conclusion Our analysis suggests an outbreak of clonal dissemination, presumably due to nosocomial transmission. This study represents the first documented outbreak of NDM-5-producing E. coli mediated by IncFII in infants. Close monitoring is urgently needed to prevent and control the spread of this difficult-to-treat superbug.

This study aimed to investigate the clinical features, distribution, and antimicrobial susceptibility of Nocardia species isolated from pulmonary nocardiosis cases in a tertiary hospital in China. The species were collected from January 1, 2018, to May 31, 2019, and identified using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry or polymerase chain reaction. Antimicrobial susceptibility testing was performed using the broth microdilution method. Within the 44 Nocardia species, N. farcinica was the most frequently identified species (n = 36), followed by N. nova (n = 5), N. otitidiscaviarum (n = 1), N. cyriacigeorgica (n = 1), and N. transvalensis (n = 1). The top 3 predisposing factors of pulmonary nocardiosis were chronic obstructive pulmonary disease (45.5%), hypertension (34.1%), and tuberculosis (31.8%). All 44 Nocardia species were susceptible to amikacin, trimethoprim/sulfamethoxazole, and linezolid. The resistance rates of Nocardia to amoxicillin-clavulanic acid, ciprofloxacin, clarithromycin, ceftriaxone, tobramycin, and imipenem were 4.5%, 9.1%, 79.5%, 72.7%, 63.6%, and 38.6%, respectively. Two Nocardia strains had decreased sensitivity to trimethoprim/sulfamethoxazole. In conclusion, N. farcinica was the most frequently isolated Nocardia species in the First Hospital of Changsha. All the isolated clinical Nocardia species showed susceptibility to amikacin, trimethoprim/sulfamethoxazole, and linezolid, suggesting that these drugs can be primary therapeutic choices for treating Nocardia infections.

International audience; We perform a theoretical study of an atomically thin, two-dimensional layer obtained by positioning atoms at the vertices of the classical Pythagorean tiling. This leads to an unusual geometrical pattern that is only stable for the three halogens Cl, Br, and I. In this Pythagorean structure, halogen atoms are arranged in strongly bound diatomic units that bind together by weaker electrostatic bonds. The energy of these phases is competitive with those of the low-temperature phase of the halogens and the two-dimensional layer obtained by exfoliating it. The Pythagorean layers are semiconducting, with an unusual band structure composed of very mobile holes and extremely heavy electrons. They are also soft, exhibiting small values of the elastic constants and a very low energy flexural mode. Analysis of the allowed Raman transitions reveals breathing-like modes that might be used to fingerprint, experimentally, the Pythagorean structure. Finally, we present a series of substrates that, due to lattice matching and compatible symmetry, can be used to stabilize these peculiar two-dimensional layers.

In the past decade we have witnessed the appearance of large databases of calculated material properties. These are most often obtained with the Perdew-Burke-Ernzerhof (PBE) functional of density-functional theory, a well established and reliable technique that is by now the standard in materials science. However, there have been recent theoretical developments that allow for increased accuracy in the calculations. Here, we present a dataset of calculations for 175k crystalline materials obtained with two functionals: geometry optimizations are performed with PBE for solids (PBEsol) that yields consistently better geometries than the PBE functional, and energies are obtained from PBEsol and from SCAN single-point calculations at the PBEsol geometry. Our results provide an accurate overview of the landscape of stable (and nearly stable) materials, and as such can be used for reliable predictions of novel compounds. They can also be used for training machine learning models, or even for the comparison and benchmark of PBE, PBEsol, and SCAN.

We perform a systematic study of the family of quaternary halide perovskites in order to find good candidates for transparent p-type conduction. This is achieved by using high-throughput techniques based on density-functional theory, and by screening the materials with regard to their stability, electronic band gap, and hole effective masses. We find a total of 17 double perovskites with promising properties, 10 of which not including toxic or rare chemical elements. Furthermore, in most of these systems, doping might be achieved by adjusting the chemical potential of the two cations during the growth process. Due to chemical similarity, we expect that these materials are compatible with current photovoltaic technology based on organic halide perovskites.

To predict and compare the main reinforcement effects of the key precipitation phases Mg2Cu3Si, Mg2Si and MgCu2 in Mg-Cu-Si alloy, the structural, mechanical and electronic properties of these phases have been studied by ab initio calculations. The lowest formation enthalpy and cohesive energy indicate that Mg2Cu3Si has the strongest alloying ability and structural stability. The mechanical modulus indicates that Mg2Cu3Si has the strongest resistance to reversible shear/volume distortion and has maximum hardness. The characterization of brittle (ductile) behavior manifests that MgCu2 has favorable ductility. Meanwhile the evaluation of elastic anisotropy indicates that Mg2Si possesses elastic isotropy. Debye temperature prediction shows that Mg2Si and Mg2Cu3Si have better thermal stability. To achieve an unbiased interpretation on the phase stability and mechanical behavior of these precipitation phases, the density of states and differential charge densities are also analyzed. The current study deepens the comprehensive understanding of main reinforcement effects of these precipitation phases on Mg-Cu-Si alloys, and also benefits to optimize the overall performances of Mg-Cu-Si alloy from the hardness, ductility and thermal stability by controlling these second precipitation phases during the heat treatment process.

Nine possible native point defects in MgCaSi have been studied by employing density functional theory based ab initio calculations. The complex chemical potential limits are first determined using a two-dimension (ΔμMg, ΔμCa) diagram, then the defect formation energies as a function of the atomic chemical potential are gained. The energetic results show that under Mg-rich conditions, the most favorable defect is MgCa rather than MgSi, while CaMg is predominant compared to CaSi under Ca-rich conditions. The bonding energy is first introduced to uncover the intrinsic feature of defect formation energy. The local geometric distortion around CaMg, MgSi, and CaSi antisite defects gradually increases due to the smaller atomic radii from Ca to Mg and Si, showing the important role of the geometrical mismatch. The density of states indicates that the higher stability of CaMg and MgCa originates from the smaller deviation of the Fermi level from the pseudo-gap.

Ti-doping and Li-vacancy (VLi) crucially affect the dehydrogenation properties of LiBH4 surface. However, theoretical investigations on individual Ti or VLi could not completely explain experimental observations. In this article, we investigated the synergistic effects of co-existing Ti and VLi on the dehydrogenation properties of LiBH4 (010) surface. Our result shows mutual stabilization between Ti-dopant and Li-vacancy, implying expectable co-existence of Ti and VLi. Thermodynamic destabilization from composite Ti + VLi defect agrees with experiments better than that from single Ti or VLi. The kinetic barrier on Ti + VLi decorated surface also becomes closer to experimental result. Therefore, the co-existing Ti and VLi synergistically and crucially affect the dehydrogenation thermodynamics and kinetics on LiBH4 surface. The electronic structure further reveals strong H H, B B, and Ti B bonds as well as weakened B H bond in transition states on Ti + VLi co-existed surface, which is the main factor of low kinetic barrier.

Purpose Outbreaks of infection due to carbapenem-resistant Enterobacterales (CRE), including New Delhi metallo-β-lactamase (NDM)-producing Escherichia coli, have been increasingly reported worldwide, primarily in adults and rarely in children. The goal of this study was to characterize an outbreak of infection caused by NDM-5-producing E. coli in a children’s hospital in China. Methods A total of 86 CRE isolates were collected from 85 hospitalized children between June 2017 and May 2018. These isolates were subjected to multiple phenotypic and molecular tests, including in vitro antimicrobial susceptibility testing, PCR, pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and whole-genome sequencing (WGS). Results Among the 86 CRE isolates, we identified 9 NDM-5-producing E. coli isolates, with 5 of them sharing the same PFGE pattern, same MLST type (ST410), same plasmid replicon type (IncFII), and nearly the same set of additional resistance genes. All 9 isolates were resistant to most antimicrobial agents, including carbapenems, cephalosporins, and levofloxacin, while being sensitive to trimethoprim/sulfamethoxazole, amikacin, tigecycline, and colistin. According to the clinical background, all 9 isolates were collected in a period of < 3 months from infants among whom there was overlap in the time of hospitalization. None of them had a travel history. Conclusion Our analysis suggests an outbreak of clonal dissemination, presumably due to nosocomial transmission. This study represents the first documented outbreak of NDM-5-producing E. coli mediated by IncFII in infants. Close monitoring is urgently needed to prevent and control the spread of this difficult-to-treat superbug.

We investigate, using a systematic computational approach, the possibility of the existence of two-dimensional quasicrystalline phases of binary metal-oxides. Our approach relies on the construction of the complete two-dimensional binary phase diagram through the use of unbiased global structural prediction methods. We then identify, in the low-energy periodic phases, structural elements that can be used to generate quasicrystalline phases through an inflation process. In this way we obtain chemically consistent two-dimensional quasicrystal approximants of both barium and titanium oxides. In the proposed structures, the metallic sites occupy the vertices of the aperiodic square-triangle tiling, while the oxygen atoms decorate the interior of the polygons. We then study the properties of the approximants, both free-standing and deposited on a metallic substrate. Finally, we discuss in which circumstances the formation of these phases seems to be favored.

Atomic diffusion in pure and transition element (TM = Ti, Y, Zr or Hf)-doped Al3Sc has been studied mainly along vacancy-mediated diffusion paths. After the point defect formation energies are determined, the energy profiles for dominant diffusion paths are obtained using climbing image nudged elastic band method. The energetic results show that Al atom diffusion through nearest-neighbor jump mediated by Al vacancy is most favorable due to the lowest activation barrier, the other diffusion processes would make very small contribution due to the high activation barrier or unstable final state. The dominant Sc atom diffusion mechanisms are the Al-vacancy mediated nearest-neighbor jump under Al-rich condition and antistructure sublattice mechanism under Sc-rich condition. The 6-jump cycle and next nearest-neighbor jump are greatly restricted with high activation barriers. Moreover, effect of typical transition element (Ti, Y, Zr or Hf) doping on atomic diffusion is further studied. The activation barriers for dominant diffusion mechanisms increase with increasing atom size mismatch in sequence of Zr

Thermal properties and thermoelasticity of L12 Al3RE (RE = Er, Tm, Yb, Lu) phases have been studied by first principles calculations combined with density functional perturbation theory and quasi-harmonic approximation. In the temperature range considered, the calculated thermal properties including equilibrium volume, isothermal bulk modulus, Grüneisen parameters for different Al3RE phases exhibit analogous variation tendency and the numerical values are associated with the atomic radius of RE. The calculated thermal expansion and heat capacity for different Al3RE are almost indistinguishable from each other. The obtained elastic constants and polycrystalline elastic moduli exhibit gentle softening trends with temperature, and the variation tendency is also very similar. In the temperature range considered, Al3RE phases are nearly isotropic. The present study would be valuable for future investigation and design of high temperature Al alloys. Keywords: First principles calculations, Thermal properties, Thermoelasticity, Density functional perturbation theory, Quasi-harmonic approximation

The newly synthesized novel double-Ga layer nanolaminated carbide Mo2Ga2C is stimulating tremendous research interests. In the present exploration of Mo2Ga2C structure, another plausible metastable structure with close-packed Ga layers is predicted from density functional calculations. This new structure (denoted as m-structure) is slightly less stable by only 52 meV/atom than the experimentally determined structure (e-structure) with on-top stacked Ga layers. Importantly, this m-structure is dynamically stable from the calculated phonon dispersion. Moreover, the stability behavior of this m-structure under compression shows that possible phase transition from e-phase to m-phase could occur under a pressure above 24.3 GPa, which requires further experimental confirmation. Phase transition model is proposed, and the energy barrier for phase transition is further derived. The electronic structures show that Mo–C bonds and Ga–Ga bonds are weaker in metastable m-phase than in e-phase. During compression, more strengthening of Ga–Ga and Mo–Ga bonds and less weakening of Mo–Mo bonds in m-phase explain the stabilization of m-phase under pressure.

The elastic properties of L1 2 -type Al 3 Sc at high temperature have been studied using the first-principles calculations combined with the quasi-harmonic approximation. The obtained elastic constants and polycrystalline elastic moduli exhibit a very gentle descent trend with increasing temperature. Elastic anisotropy of Al 3 Sc is slightly enhanced with increasing temperature, while the brittle nature is insensitive to temperature. The relevant important thermodynamic properties including thermal expansion coefficient and heat capacity are further derived and discussed. The moderate variation of elastic properties and the thermal properties may be attributed to the slightly weakened Al–Sc covalent bonding with temperature increasing. Our results would be valuable for further experimental study of high temperature mechanical properties of the relevant Al-based alloys.

A comparative study of single- and co-substitution of Ti on dehydrogenation of Mg2NiH4 has been carried out from first-principles calculations based on density functional theory. In comparison with Ti single-substitution, the formation enthalpy in co-substituted Mg2NiH4 is higher, showing the lower thermodynamic stability. In Ti co-doped Mg2NiH4, the average Ni H bond length of entire unit cell is larger, implying weaker Ni H bonds and lower stability of complexes NiH44−. Ti co-substitution further shows a more favorable dehydrogenation effect on Mg2NiH4 due to lower hydrogen dehydrogenation energy, and significantly reduces the dehydrogenation reaction enthalpy of Mg2NiH4 by about 30% compared to the pure state. Further calculated electronic structure demonstrates that the co-substituted Mg2NiH4 displays a metallic behavior with the Fermi level locating at the doping band, and the underlying mechanism for improving dehydrogenation properties of co-substituted Mg2NiH4 can be attributed to the weakened Ni H interactions together with the narrowed energy gap.

The structural evolution and electronic mechanism for KBH 4 phase transition have been systematically investigated using first-principles calculations. The present results demonstrate experimentally observed stability order of α-KBH 4 > β-KBH 4 > γ-KBH 4 , and the predicted transition pressure at 0 K for cubic → tetragonal → orthorhombic phase transformation agrees reasonably with experimental measure. The atomic process indicates that KBH 4 structural evolution is closely related to rotation and deformation of [BH 4 ] − clusters as well as shift of [BH 4 ] − clusters and K atoms. Along with phase transformation, the band gap of KBH 4 narrows, the B H covalent bond weakens while K H interaction enhances, the K K anti-bonding and coulomb repulsion are also stronger.

The crystal structure of LiCa(AlH4)3 was investigated via first principle calculations, especially the positions of hydrogen atoms undetected in XRD experiments were predicted, then the thermodynamic favourability of the experimentally reported structure with respect to several candidates from the inorganic crystal structure database (ICSD) was confirmed. It is found that hexagonal packing of AlH4 layers along the c axis is present in LiCa(AlH4)3, and the detailed geometrical feature is further revealed. The electronic structures show that in LiCa(AlH4)3 the Li–AlH4 interaction is more covalent than in LiAlH4, while the Ca–AlH4 covalence is less than in Ca(AlH4)2. The overall stronger covalence in LiCa(AlH4)3 leads to weakened Al–H bonds. The Li–H interaction in LiCa(AlH4)3 dramatically turns out to be strong bonding, opposite to the Li–H anti-bonding in LiAlH4. The Ca–H bonds are more anti-bonding in LiCa(AlH4)3.

VxWorks operating system has been widely used in the field of embedded real-time operating system for its good reliability and excellent real-time performance. In this paper, the robot PC control interface is designed under VxWorks development environment. By reading the 24-bit true color bitmap, the image data is stored in memory, and window is created using WindMl multimedia database, bitmap is created and displayed in the window, background is displayed using the entire bitmap, buttons and text boxes are displayed by modifying and updating the corresponding position image display memory. The paper gives some modules of code, the method used is simple common, and the design interface is beautiful.

In this paper, the necessity and significance of combined training of Postgraduate is analyzed. Game rules, strategies and payoffs is introduced about the combined training of Postgraduate. The application problem is researched based on game theory about the mode selection of combined postgraduate.

The Cu-doping effects on dehydrogenation of MgH2 (001) and (110) surfaces were investigated by using first-principles calculations. On the basis of the calculation results of total energy, the Cu dopant prefers to occupy the interstitial site on both surfaces rather than substitute a Mg atom, and the Cu dopant bonds with four adjacent H ions to form a CuH4 cluster. The electronic structures show that Cu–Mg and Cu–H interactions strongly weaken Mg–H interactions, which leads to a reasonable expectation of decreased dehydrogenation temperature. The kinetic barriers for Cu-doped (001) and (110) surfaces are, respectively, reduced to 1.83 and 1.48 eV, showing that improved kinetics can be expected due to the much lower desorption barriers on both Cu-doped surfaces. The present results are beneficial to resolve the disputes between previous reports on the catalytic effects of Cu-doping in the MgH2 system.

The pressure dependence of elastic properties of Mo2Ga2C is studied via first-principles calculation. The present investigation shows that differing from other MAX phases, in Mo2Ga2C the [Formula: see text] is larger than [Formula: see text], because of the strong Ga–Ga interlayer bonds along [Formula: see text]-axis. Moreover, under pressure, the [Formula: see text] increases more rapidly, originating from the faster strengthening of Ga–Ga bonds. Interestingly, elastic constants [Formula: see text] soften under high pressure (more than 20 GPa). Especially, the calculated phonon structure demonstrates that transverse acoustic (TA) phonon mode also softens under pressure, implying possible phase transition. The reduction of [Formula: see text] and softening of phonon mode are attributed to significantly weakened Mo–Mo interaction in contrast to the strengthening of Ga–Ga bonds under high pressure. Our present results further indicate that Mo2Ga2C is more ductile under pressure.

Structural and elastic properties of La{sub 2}Mg{sub 17} with layer structure have been investigated within framework of the density functional theory. Different from the general layer-structured materials, the obtained c/a is less than unity. The calculated elastic constants C{sub 33} is larger than C{sub 11}, being novel in comparison with other alloys with layer structure. The calculated bulk, shear and Young’s modulus of La{sub 2}Mg{sub 17} are higher than other Mg–La alloys with higher La content, implying the stronger covalent bonding. Moreover, the elastic isotropies of La{sub 2}Mg{sub 17} are more excellent. The electronic structure within basal plane is highly symmetric, and the electronic interaction within basal plane is slightly weaker than one between basal planes, which reveal the underlying mechanism for the structural and elastic properties of La{sub 2}Mg{sub 17}. - Graphical abstract: The crystal structure (a) and the atomic positions for (b) (0 0 0 2), (c) (0 0 0 4) and (d) (1 2{sup ¯} 1 0) plane of La{sub 2}Mg{sub 17}. Display Omitted - Highlights: • The c/a of La{sub 2}Mg{sub 17} is anomalously less than unity. • It is novel that for La{sub 2}Mg{sub 17} the elastic constants C{sub 33} is larger than C{sub 11}.more » • The elastic modulus of La{sub 2}Mg{sub 17} is higher than other Mg–La alloys. • The elastic isotropy of La{sub 2}Mg{sub 17} is excellent. • The electronic structure within basal plane is highly symmetric.« less

In this paper, the laser sensor is used to detect environmental information. The problems of maps building of mobile robot are researched in the indoor structured environment. Least squares algorithm is adopted to build local maps, and a method of dynamic partition are presented based on the distance of adjacent points and angle. For accomplishing the self-localization and route planning of the mobile robot in the indoor environment lacking of the prior map, this paper present the method of the global map building based on the match of the feature points and the characteristic line. The experiments show the methods presented are effective and practicable.

Weighted generalized list (WGL) can effectively express multi-variate polynomial. In this paper, variable ordering algorithm, variable replacement algorithm and variable mergence algorithm for WGL are presented. Based on variable replacement algorithm, variable ordering algorithm and variable merging algorithm, an algorithm of backward-construction WGL is proposed, which is used to verify the equivalence between the behaviors specification and register transfer level (RTL) implementation of polynomial datapaths. Experimental results show that the proposed method is effective.

For polishing friable complex transparent pieces surface, compliant mechanism is used on the polishing robot in this paper. Compliant mechanisms on the polishing robot are designed and installed. Polishing experiments are carried out without compliant mechanisms and with compliant mechanisms. The experiments results show that the robot can complete better polishing tasks with compliant mechanisms, through the wrist force sensor collecting the polishing force, and controlling the proper compression height of compliant devices.

In this paper, in order to achieve high-precision trajectory control of grinding robot, the method of computed torque control is proposed based on PD feedback, a single-joint robot experimental platform was built, position and velocity tracking experiment is carried out with empty Load and load. Experimental results show that the method of computed torque based on PD feedback control has the characteristic of quick response speed and small position tracking error.

The crystal and electronic structure of the title compound is investigated by first principle DFT calculations.

Structural and elastic properties of La{sub 2}Mg{sub 17} with layer structure have been investigated within framework of the density functional theory. Different from the general layer-structured materials, the obtained c/a is less than unity. The calculated elastic constants C{sub 33} is larger than C{sub 11}, being novel in comparison with other alloys with layer structure. The calculated bulk, shear and Young’s modulus of La{sub 2}Mg{sub 17} are higher than other Mg–La alloys with higher La content, implying the stronger covalent bonding. Moreover, the elastic isotropies of La{sub 2}Mg{sub 17} are more excellent. The electronic structure within basal plane is highly symmetric, and the electronic interaction within basal plane is slightly weaker than one between basal planes, which reveal the underlying mechanism for the structural and elastic properties of La{sub 2}Mg{sub 17}. - Graphical abstract: The crystal structure (a) and the atomic positions for (b) (0 0 0 2), (c) (0 0 0 4) and (d) (1 2{sup ¯} 1 0) plane of La{sub 2}Mg{sub 17}. Display Omitted - Highlights: • The c/a of La{sub 2}Mg{sub 17} is anomalously less than unity. • It is novel that for La{sub 2}Mg{sub 17} the elastic constants C{sub 33} is larger than C{sub 11}.more » • The elastic modulus of La{sub 2}Mg{sub 17} is higher than other Mg–La alloys. • The elastic isotropy of La{sub 2}Mg{sub 17} is excellent. • The electronic structure within basal plane is highly symmetric.« less

Background and Purpose: Cardiac myxoma is a major primary heart tumor which often causes unexpected symptoms or sudden death. This present study was designed to investigate its clinical pathological features and biological behavior. Methods: A retrospective analysis of the clinical pathologic and immunohistochemical features of 66 cases with cardiac myxoma was conducted. Results: In 66 patients with cardiac myxoma, 61 cases had involvement of the left atrium, one case in both the right ventricular and left atria. The female: male ratio was 2.7:1. Patients had symptoms of blood flow obstruction and systemic alterations with performance of arterial embolization. Tumors were spherical, lobulated or irregular in shape, and soft and brittle. Immunohistochemical markers of vimentin and CD34 in tumor cells were positive. Conclusion: Cardiac myxoma always exists in the left atrium and is more common in women, with diverse clinical manifestations and pathomorphism. Although proliferative activity and the recurrence rate are low, in addition to thorough surgical resection, strengthened review is important for young patients.