Search

Aims/Introduction Materials and Methods Results Conclusions The aim of the present study was to evaluate the status of glycemic control, and assess the effects of the disease course and comprehensive management measures on the blood glucose level in children and adolescents with type 2 diabetes mellitus.The study collected the clinical data of type 2 diabetes patients in Beijing Children's Hospital from January 2015 to September 2020. Patients were grouped based on the disease course to compare their glycated hemoglobin (HbA1c) level, islet β‐cell function, insulin resistance and comprehensive management measures.Of the 170 participants, the median disease course was 2.0 years (interquartile range [IQR] 1.0–4.0 years). The baseline HbA1c was 11.2% (IQR 9.2–12.4%). According to the grouping by the disease course, the median HbA1c was the lowest (5.7% [IQR 5.3–6.1%]) in the half‐year course group and the highest in the 4‐year course group (9.0 [IQR 6.8%–11.3%]). Compared with the group with a disease duration <2 years, patients in the >4 years group had a lower proportion of patients with HbA1c <7% (29.2% vs 66.2%), a lower homeostasis model assessment of β‐cell function, and a lower proportion with a controlled diet, moderate‐intensity exercise, regular follow up and no drug treatment. We deemed HbA1c as the dependent variable, and found that disease duration, homeostasis model assessment of β‐cell function at follow up, continuous moderate‐intensity exercise, regular review and treatment regimen were significant influencing factors for glycemic control.Children and adolescents with type 2 diabetes and a prolonged disease course showed poor glycemic control and decreased islet β‐cell function. A good lifestyle, especially moderate‐intensity exercise, can help such cases better control their blood glucose level. [ABSTRACT FROM AUTHOR]

Background and Purpose. Fetal overgrowth can pose a serious threat to the safety of a mother and child. Early identification of high-risk pregnant women and timely pregnancy intervention and guidance are of great value in preventing the development of giant babies and improving adverse maternal and infant outcomes. The current clinical methods for predicting macrosomia mainly rely on obstetric examination and imaging, but their accuracy is controversial. And there is no accepted method for accurately predicting macrosomia. We investigated the risk factors influencing the occurrence of macrosomia and established a prediction model for the occurrence of macrosomia to provide a reference basis for interventions to prevent macrosomia. Method. A retrospective selection of 93 women who were hospitalized in our hospital from March 2019 to May 2022 with a singleton pregnancy and delivered at term with macrosomia were the study group. And 356 women who delivered a normal size baby during the same period were the control group. The variables that were associated with the onset of macrosomia were screened from maternal medical records. Logistic regression models, random forest, and CART decision tree models were developed using the screened variables as input variables and whether they were macrosomia as outcome variables, respectively. The performance of the three models was evaluated by accuracy, precision, recall, F1 score, and receiver operating characteristic curve (ROC). Result. The risk prediction models for the onset of macrosomia, logistic regression model, random forest model, and decision tree, were successfully developed, with accuracies of 0.904, 1.000, and 0.901 in the training set and 0.926, 0.582, and 0.852 in the validation set, respectively. The AUC in the training set were 0.898, 1.000, and 0.789, and in the validation set were 0.906, 0.913, and 0.731, respectively. In general, the logistic regression model has the highest diagnostic efficiency, followed by the random forest model. Conclusion. Logistic regression models have high application value in the assessment of predicting the risk of macrosomia, and it is suggested that the advantages of logistic regression models and random forest models should be combined in future studies and applications to make them work better in the prediction of the risk of macrosomia. [ABSTRACT FROM AUTHOR]

The Carboniferous volcanic reservoirs in Junggar Basin contain rich hydrocarbon resources, implying a great exploration potential, so that they have become a key replacement target for "three-dimensional exploration". The study on the Carboniferous volcanic reservoirs and their hydrocarbon accumulation elements is significant for clarifying the orientation for exploration. In this paper, based on 37 reserves reports and 3 200 reservoir test data, the Carboniferous volcanic reservoirs in Junggar Basin were discussed from the prospective of lithology and lithofacies, physical properties, reservoir types, main controls on hydrocarbon accumulation, and hydrocarbon accumulation patterns. It is found that the Carboniferous in the basin is mostly in the multi-island ocean-volcanic island arc structural-sedimentary environment, so it is geologically eligible for forming in-situ volcanic reservoirs. The volcanic rocks are: (1) mostly distributed along deep and large faults, with the lithology and lithofacies controlled by volcanic architectures; (2) dominantly lava, followed by volcaniclastic lava and volcaniclastic rock; (3) distributed in the periphery of hydrocarbon-generating sag and within the source rocks horizontally, and concentrated in the weathering crust at the top longitudinally, possibly leading to reworked weathering crust reservoir; and (4) liable to form inner reservoirs. The volcanic reservoirs can be concluded into four hydrocarbon accumulation patterns, i.e., self-generating & self-storing in paleo-uplift and vertical migration, self-generating & self-storing in paleo-uplift and lateral migration, young-generating & old-storing in fault zone and vertical migration, and young-generating & old-storing in paleo-uplift and lateral migration. Future exploration will focus on the effective source rock development and hydrocarbon supply zones and the self-generating & self-storing and young-generating & old-storing patterns. The exploration prospects are determined to be the Ludong-Wucaiwan-Baijiahai slope belt and the southern slope belt of the Shaqi uplift (self-generating & self-storing pattern) in eastern Junggar, and the fault and nasal arch zone at the northwestern margin and the nasal arch zone (deep and large structure) in the Luxi area (young-generating & old-storing pattern) in western Junggar. [ABSTRACT FROM AUTHOR]

The thermodynamic properties of the tetragonal RNi2B2C (R=Y, Lu) are investigated by means of the density-functional theory (DFT) and density-functional perturbation theory (DFPT) within the quasiharmonic approximation (QHA). The phonon dispersion curves and phonon total and partial density of states are studied, and it is found that the phonon branches can be divided into three obvious regions: a low-frequency region (LFR), an intermediate-frequency region (IFR), and a high-frequency region (HFR). The temperature dependence of the various quantities including isothermal bulk modulus, thermal expansion coefficient, and heat capacity is obtained, and the variation features of these quantities with temperature are discussed in detail. [ABSTRACT FROM AUTHOR]

The interfacial adhesion and separation of Al/TiC interfaces are investigated using the first-principles methods based on density functional theory. The adhesive energies of Al/TiC interfaces predicted by quasiharmonic approach are almost unaltered with temperature (0–800 K). However, the wetting experiments show that the adhesive energy increases with temperature (973–1273 K). In order to clarify these different results, typical structural models for (1 0 0) and (1 1 1) Al/TiC interfaces are constructed. For (1 0 0) Al/TiC interfaces, the adhesive energies are about 1 J/m 2 for 5Al/4TiC-C, 5Al/4TiC-Ti, 4Al/5TiC-C and 4Al/5TiC-Ti interfaces, that are smaller than 1Al/1TiC-C. For (1 1 1) Al/TiC interfaces, the adhesive energies of C terminated interfaces are larger than that of Ti terminated interfaces. But, the most stable interface structure is AlB stacking for both Ti and C terminations. And the adhesion of AlA stacking is the weakest. Furthermore, the difference charge density and density of states are presented to understand the nature of the different interfacial adhesion. Finally, in order to fit the experimental results, it is suspected that the 1Al/1TiC interface may transform to 5Al/4TiC, 4Al/5TiC and Ti-AlA interfaces with the increasing temperature (973–1273 K). [ABSTRACT FROM AUTHOR]

In the paper, we investigate the core width of superpartials and dissociated width of the 〈110〉{1-10} superdislocations in CaSiO perovskite under pressures of 30 and 100 GPa by using the modified P-N dislocation equation. Our results show that when taking into account the discrete effect correction, core width of superpartials and dissociated width become much wider, and both of them increase significantly with the increase of the superdislocation angle. Furthermore, it is found that the dissociated width and core width of superpartials are determined by value of the unstable stacking fault energy and antiphase boundary energy, which are independent of the position of unstable stacking energy. Interestingly, the Peierls stress of superpartials can be predicted by using the variational method to solve the modified P-N dislocation equation. [ABSTRACT FROM AUTHOR]

The structural stability of D0 22 TiAl 3 alloyed with Zn, Cu and Ag are systematically investigated using first-principles calculations. There is a phase transition from D0 22 to L1 2 with the increasing of the concentrations of Zn, Cu and Ag, respectively. Based on the predicted elastic constants and Pugh's ratio, the ductility of TiAl 3 are improved due to the phase transition. The generalized stacking fault energies and cleavage energies are also presented. The reduced unstable stacking fault energy and antiphase boundary energy of 〈110〉{001} slip systems may weaken the stability of D0 22 TiAl 3 . Furthermore, Rice and Zhou–Carlsson–Thomson criterions are used to reveal the brittle/ductile mechanism, which is in agreement with Pugh's view. Finally, the electronic properties are also presented. The DOS suggests that weakened p–d interactions between Al and Ti atoms but enhanced d–d interactions between Ti and alloying atoms in TiAl 3 result in the improvement of ductility. [ABSTRACT FROM AUTHOR]

The transformation pathways between vitual long period stacking-ordered Mg are investigated using first-principles methods. Two kinds of slip modes, multi-slip-planes mode (M mode) and single-slip-plane mode (S mode), are proposed to calculated the generalized stacking fault energy curves during the transformation process. Based on the energy barriers, the optimized transformation pathways can be obtained. The energy barriers of M mode and S mode are the same for 2H → 6H 2 , 6H 1 → 6H 2 , 14H 4 → 14H 2 and 14H 4 → 14H 5 , respectively. However, the energy barriers of M mode are larger than that of S mode for these transformation with the consideration of vacuum space. For 2H → 6H 1 and 14H 1 → 14H 3 , the energy barriers of M mode are smaller than that of S mode. The energy barriers of M mode are larger than that of S mode for 18R 1 → 18R 2 and 14H 2 → 14H 5 . It is found that the energy barriers increase with the increasing of the numbers of AA stacking of the different slip modes. [ABSTRACT FROM AUTHOR]

The phase stability and site preference of alloying elements W, Mo, Sc and Yb in L1 0 and B2 TiAl alloys were investigated using first-principles calculations. It is found that there will be a phase transition from L1 0 to B2 structure when the concentrations of W and Mo are about 10.50 at.% and 11.50 at.%, respectively. However, there is no phase transition for L1 0 TiAl with Sc and Yb. The elastic constants, bulk modulus, shear modulus, Poisson's ratio and hardness of TiAl alloys are also systematically presented. Based on Pugh ratio, the brittle/ductile transition are predicted for TiAl with W, Mo, Sc and Yb. It is found that W and Mo can effectively improve the ductility of TiAl due to the phase transition. Finally, the density of states is also used to analysis the mechanical properties, which is consistent with brittle/ductile transition map of TiAl based alloys. [ABSTRACT FROM AUTHOR]

The effect of virtual long-period stacking-ordered (v-LPSO) structures (6H, 10H, 14H, 18R and 24R) on the second order elastic constants and third order elastic constants of pure Mg are systematically investigated using first principles methods combined with finite strain theory. The predicted lattice constants and formation energies are in a good agreement with the available data. The pressure effect on anisotropy, Pugh ratio, Vickers hardness and Debye temperature are also presented. The anisotropy and Pugh ratio of 2H and v-LPSO Mg are not sensitive to pressure, except for 10H. The anisotropy of 10H increases with pressure, but Pugh ratio decreases. v-LPSO structures can only slightly improve the ductility of Mg. It is also found that 2H and 18R have nearly the same Pugh ratio and Vickers hardness. [ABSTRACT FROM AUTHOR]

The phase stability, mechanical properties and electronic structure of C11 b and C40 MoSi 2 with alloying elements Al, Mg and Ge were systematically investigated using first principles methods. The calculated lattice constants and elastic constants of C11 b and C40 MoSi 2 are in good agreement with the previous results. It is found that there is a phase transition from C11 b to C40 when the concentrations of Al and Mg reach ∼7 at.% and ∼6 at.%, respectively. Based on the elastic constants, the anisotropy, ductility, hardness and melting temperatures are presented for MoSi 2 with alloying elements. For C11 b , the ductility will be enhanced by increasing the concentrations of Al or Mg. Simultaneously, hardness will be reduced by the increasing of Al or Mg. Ge have a reverse effects. For C40, the ductility is reduced weakly by Al or Mg. In addition, the effects of substitution of Mo by Nb with Si substitution of Si by Al, Mg and Ge are also investigated. Nb and Mg codoping can improve the ductility of MoSi 2 . Finally, the density of states is used to analysis the effects of alloying elements on the mechanical properties, and the results are in consistent with the predictions based on elastic constants. [ABSTRACT FROM AUTHOR]

We have employed an improved Peierls-Nabarro (P-N) equation considering the discreteness effect of crystals to study the properties of 1/2 〈110〉 dislocation in the (001) plane in cubic anti-perovskites type superconducting materials ZnCNi and MgCNi under different pressure. The generalized-stacking-fault energy (GSFE) curves were calculated by using first-principles density functional theory (DFT). The core structures and Peierls stress of the screw, mixed, and edge dislocation in the pressure range 0-50 GPa have been systematically researched by solving the modified P-N dislocation equation combining with calculation of GSFE curves. With increasing pressure, the Peierls stress increases, but the core width decreases, and the Peierls stress of mixed dislocations is in the region between screw and edge dislocations. Finally, the electronic structure further reveals the underlying mechanisms for the effects of dislocation on the electronic properties. [ABSTRACT FROM AUTHOR]

The elastic constants, generalized stacking fault energies, and surface energies of NiAl and FeAl have been investigated by using the first principles methods combined with a quasiharmonic approach. Pugh ratio, Cauchy pressure, elasticity anisotropy and Rice ratio are presented at different temperature. It is interesting to find that the anisotropy of NiAl decreases with increasing temperature, but FeAl increases. NiAl has better ductility than FeAl according to the Pugh ratio and the Cauchy pressure. However, the Rice ratio shows the opposite result. Furthermore, the dislocation core structure of NiAl and FeAl is also presented based on an improved Peierls–Nabarro theory. [ABSTRACT FROM AUTHOR]

The second-order elastic constants (SOECs) and third-order elastic constants (TOECs) of superconducting MgB are investigated by first principles methods combined with homogeneous deformation theory. The Anderson-Grüneisen parameter is obtained from the SOECs and TOECs. The obtained value is 2.13, that is in consistent with the experimental result. The effective elastic constants and Debye temperature are also predicted from SOECs and TOECs, which increase with the increasing of pressure. [ABSTRACT FROM AUTHOR]

Effects of Ni vacancy, Ni antisite in Al sublattice, Cr in Al sublattice, Pt in Ni sublattice on the second-order elastic constants (SOECs) and third-order elastic constants (TOECs) of the B2 NiAl have been investigated using the first-principles methods. Lattice constant and the SOECs of NiAl are in good agreement with the previous results. The brittle/ductile transition map based on Pugh ratio G / B and Cauchy pressure P c shows that Ni antisite, Cr, Pt and pressure can improve the ductility of NiAl, respectively. Ni vacancy and lower pressure can enhance the Vickers hardness H v of NiAl. The density of states (DOS) and the charge density difference are also used to analysis the effects of vacancy, Ni antisite, Cr and Pt on the mechanical properties of NiAl, and the results are in consistent with the transition map. [ABSTRACT FROM AUTHOR]

The elastic properties and generalized stacking fault energy curves of antiperovskite-type Ni-rich nitrides MNNi (M = Zn, Cd) under different pressure have been obtained from the first-principles calculations. By using the variational method, the core width and Peierls stresses of $\frac {1}{2}\langle 110\rangle \{110\}$ edge dislocation and screw dislocation in ZnNNi and CdNNi within the improved Peierls-Nabarro (P-N) model in which the lattice discrete effect is taken into account have been investigated. Whatever the material or the pressure range, the Peierls stress of edge dislocation is smaller than that of screw dislocation. This also demonstrates that the edge dislocation is considered to be the dominant factor in determining the plastic behavior of MNNi (M = Zn, Cd) in the pressure range of 0-30 GPa. [ABSTRACT FROM AUTHOR]

We present theoretical studies for the third-order elastic constants (TOECs) of superconducting antiperovskites MNNi (M = Zn, Cd, Mg, Al, Ga, and In) using the density functional theory (DFT) and homogeneous deformation method. From the nonlinear least-square fitting, the elastic constants are extracted from a polynomial fit to the calculated strain-energy data. Calculated second-order elastic constants (SOECs) are compared with the previous theoretical calculations, and a very good agreement was found. The nonlinear effects often play an important role when the finite strains are larger than approximately 2.5 %. Besides, we have computed the pressure derivatives of SOECs and provided rough estimations for the Grüneisen constants of long-wavelength acoustic modes by using the calculated TOECs. [ABSTRACT FROM AUTHOR]

The second-order elastic constants (SOECs) and third-order elastic constants (TOECs) of MgCNi and CdCNi are presented by using first-principles methods combined with homogeneous deformation theory. The Voigt-Reuss-Hill (VRH) approximation are used to calculate the bulk modulus B, shear modulus G, averaged Young's modulus E and Poisson's ratio ν for polycrystals and these effective modulus are consistent with the experiments. The SOECs under different pressure of MgCNi and CdCNi are also obtained based on the TOECs. Furthermore, the Zener anisotropy factor, Chung-Buessem anisotropy index, and the universal anisotropy index are used to describe the anisotropy of MgCNi and CdCNi. The anisotropy of Young's modulus of single-crystal under different pressure is also presented. [ABSTRACT FROM AUTHOR]

The $\langle11\overline{2}0\rangle$ perfect dislocation in MgB is suggested to dissociate into two partial dislocations in an energy favorable way $\langle11\overline{2}0\rangle\rightarrow\frac{1}{2}\langle11\overline{2}0\rangle +\mathrm{SF}+\frac{1}{2}\langle11\overline{2}0\rangle$. This dissociation style is a correction of the previous dissociation $\langle1000\rangle\rightarrow\frac{1}{3}\langle1\overline{1}00\rangle+\mathrm{SF}+\frac{1}{3}\langle2100\rangle$ proposed by Zhu et al. to model the partial dislocations and stacking fault observed by transmission electron microscopy. The latter dissociation results in a maximal stacking fault energy rather than a minimal one according to the generalized stacking fault energy calculated from first-principles methods. Furthermore, the elastic constants and anisotropy of MgB under different pressure are investigated. The core structures and mobilities of the $\langle11\overline{2}0\rangle$ dissociated dislocations are studied within the modified Peierls-Nabarro (P-N) dislocation theory. The variational method is used to solve the modified P-N dislocation equation and the Peierls stress is also determined under different pressure. High pressure effects on elastic anisotropy, core structure and Peierls stress are also presented. [ABSTRACT FROM AUTHOR]

[Display omitted] Dislocations have been thought to generate significant effects on the performance of GaN-based devices. The intensive studies have usually focused on threading dislocations on the prismatic or pyramidal planes of wurtzite GaN. Here, we alternatively investigate the partial dislocations on the basal plane of GaN. By a combination of the fully discrete Peierls theory and first-principles calculations, the core structures and electronic properties of 90°/30° partial dislocations with glide-sets have been obtained. From the analytical displacement fields, we show that the single-period and double-period reconstructions of the partial dislocations are present. Importantly, due to the intrinsic polarity of dislocation cores, the introduction of excess charge is uncovered to strongly affect the reconstructions, exhibiting unique charge-induced structural transitions. Furthermore, the electronic density of states indicate that the stable reconstructed structures possess the defect levels inside the bulk gaps, which are localized along the dislocation lines at core regions. Our work not only extends the understanding of dislocations and their related properties in GaN but also offers fascinating guidance for designing GaN-based devices. [ABSTRACT FROM AUTHOR]

Abstract: The generalized stacking fault energies and surface energies for AgRE (RE=Sc, Tm, Dy, Tb, Ce) intermetallics with B2 structure have been investigate d using the first principle calculations. The Perdew–Burke–Ernzerhof exchange-correlation functional for the generalized-gradient-approximation is used and the electron–ion interaction is described by the full potential frozen-core projector augmented wave. The generalized stacking fault energy along , and directions in {110} plane have been calculated. The ductility and brittleness of AgRE have been discussed based on the Rice criterion by using the ratio between surface energies and the unstable stacking fault energies. The ideal shear strength and the theoretical cleavage strength are also presented. [Copyright &y& Elsevier]

Abstract: In this study, the generalized-stacking-fault energy (GSFE) surfaces for MgRE (RE=Y, Tb, Dy, Nd) intermetallics with B2-type structures have been presented using ab initio calculations. We employ the density functional theory (DFT) within generalized-gradient-approximation (GGA) and the framework of the projector augmented wave (PAW) method. Using a slab calculation, GSFE curves along {110} direction and {110} direction have been calculated. The fitted GSFE surfaces have been obtained from the Fourier series based on the translational symmetry. To judge that our computational accuracy is reasonable, we have compared our theoretical results for B2 intermetallics YAg with the previous calculated results. In comparison with YAg, the MgRE intermetallics exhibit lower unstable stacking fault energies in the direction rather than direction. So the primary slip system is in the {110} plane of B2-MgRE intermetallics. The superdislocation with the Burgers vector along will split into two superpartials because of the lower antiphase boundary (APB) energy in the {110} direction. [ABSTRACT FROM AUTHOR]

The core structure of 〈110〉{001} mixed dislocation in perovskite SrTiO is investigated with the modified two-dimensional Peierls-Nabarro dislocation equation considering the discreteness effect of crystals. The results show that the core structure of mixed dislocation is independent of the unstable energy in the 〈100〉 direction, but closely related to the unstable energy in the 〈110〉 direction which is the direction of total Burgers vector of mixed dislocation. Furthermore, the ratio of edge displacement to screw one nearly equals to the tangent of dislocation angle for different unstable energies in the 〈110〉 direction. Thus, the constrained path approximation is effective for the 〈110〉{001} mixed dislocation in SrTiO and two-dimensional equation can degenerate into one-dimensional equation that is only related to the dislocation angle. The Peierls stress for 〈110〉{001} dislocations can be expediently obtained with the one-dimensional equation and the predictive values for edge, mixed and screw dislocations are 0.17, 0.22 and 0.46 GPa, respectively. [ABSTRACT FROM AUTHOR]

Abstract: We present first-principles calculations on the generalized-stacking-fault (GSF) energies and surface properties for several HCP metals on Mg, Be, Ti, Zn, and Zr, employing density functional theory (DFT) within generalized-gradient-approximation (GGA) and spin-polarized GGA (SGGA) using the Vienna ab initio simulation package (VASP). Using a supercell approach, stacking fault energies for the [11 0] and [10 0] slip systems, and surface properties on basal plane (0001) have been determined. Our results show that GSF energy is sensitive to the primitive cell volumes and the ratio for HCP metals. A spin-polarized calculations should be considered for transition-metal Ti, Zn, and Zr. The results for Mg from this work are good with ones from the previous ab initio and the experiments. [Copyright &y& Elsevier]

In this study, a fractal simulation method for simulating resource abundance is proposed based on the evaluation results of the exploration risk and prediction technology for the spatial distribution of oil and gas resources at home and abroad. In addition, a key technical workflow for simulating resource abundance was developed. Furthermore, the model for predicting resource abundance has been modified, and the objective functions for conditional simulation have been improved. A series of prediction technologies for predicting the spatial distribution of oil and gas resources have been developed, and the difficulties in visualizing the exploration risks and predicting the spatial distribution of oil and gas resources have been solved. Prediction technologies have been applied to the Jurassic Sangonghe Formation in the hinterland of the Junggar Basin, and good results have been obtained. The results indicated that within the known area, taking the known abundance as the constraint condition, the coincidence rate of the simulated quantities of the original model and the improved model with the actual reserves reached 99.98% after the conditional simulation, indicating that the conditional simulation was effective. In addition, with the improved model, the predicted remaining resources are 0.7899 × 10 8 t, which is 65% of the discovered reserves, and the original model predicts that the remaining resources are 3.5033 × 10 8 t, which is 2.89 times greater than the discovered reserves. Compared with the area in the middle stage of exploration, the results of the improved model are more consistent, and the results of the original model are obviously larger, indicating that the improved model has a good predictive effect for the unknown area. Finally, according to the risk probability and remaining resource distribution, the favorable areas for exploration were optimized as follows: the neighborhood of the triangular area formed by Well Lunan1, Well Shimo1, and Well Shi008, the area near Well Mo11, the area east of Well Mo5, the area west of Well Pen7, the area southwest of Well Shidong1, and the surroundings, as well as the area north of Well Fang2. The application results show that these prediction technologies are effective and can provide important reference and decision-making for resource evaluation and target optimization. [ABSTRACT FROM AUTHOR]

This paper analyzes the option coordination problem of a fresh agricultural product supply chain under two supply chain structures, when the production cost and the loss rate are disrupted simultaneously. This paper provides the explicit option coordination conditions for the disrupted supply chain under two supply chain structures, and then explores the effects of the disruptions and supply chain structure on the option coordination conditions. The results suggest that it is unfavorable to apply the original coordinating contracts without disruptions to coordinate the disrupted supply chain. The coordination of the disrupted supply chain can be achieved with knowledge of the distribution of demand. In two coordinating contracts for the disrupted supply chain, the exercise price is still at the original level without disruptions while the option price deviates from the original level without disruptions. Moreover, the relationships of the coordination conditions in two supply chain structures depend on the value of the profit allocation coefficient. When the profit allocation coefficient exceeds (falls behind) a certain threshold, the option price is set at a higher (lower) value in the supplier-led supply chain structure than in the distributor-led supply chain structure, while the exercise price is set at a lower (higher) value in the supplier-led supply chain structure than in the distributor-led supply chain structure. Finally, the disrupted supply chain with any supply chain structure will perform better in the modified coordinating contracts than in the original coordinating contracts without disruptions. [ABSTRACT FROM AUTHOR]

Density-functional calculations of the formation and electronic properties of bilayer silicene and hydrogenated bilayer silicene are present. The structure optimization and phonon calculations are carried out to demonstrate that bilayer silicene has stable structure with AB stacking and preserves the linear energy dispersions near the K and K‚ points in the hexagonal Brillouin zone, and our results agree well with the previous calculations. Based on the symmetry of bilayer silicene, we study the stability of four hydrogenated bilayer silicene by the phonon-mode analysis. The configurations of semihydrogenated one-layer and semihydrogenated double-layer are confirmed as dynamically stable with no imaginary phonon frequencies. The case of semihydrogenated onelayer shows ferromagnetic ground state due to the unpaired 3p electrons, while that of semihydrogenated double-layer is predicted to be a indirect band gap semiconductor with nonmagnetic ground state. [ABSTRACT FROM AUTHOR]

Recently, two-dimensional (2D) ternary monolayer MSi2N4 (M = Mo, W) was synthesized by chemical vapor deposition. However, monolayer MSi2N4 (M = Mo, W) has an indirect bandgap, which seriously hinders its application in optoelectronic devices. Herein, we propose two MSi2N4/InS (M = Mo, W) van der Waals heterojunctions (vdWHs) possessing type-II band alignments by first-principles. Our results indicate that these vdWHs achieve an indirect-to-direct bandgap transition and exhibit fascinating optical absorption spectra in the range of visible light. Moreover, the light absorption efficiencies of both vdWHs are significantly strengthened, and the intrinsic electric field of vdWHs can effectively promote the separation of photogenerated electron–hole pairs. In particular, the most significant electron mobility of MSi2N4/InS (M = Mo, W) vdWHs is up to 6.6 × 103 cm2 V−1 s−1, demonstrating their considerable potential for optoelectronic device applications. Notably, MSi2N4/InS (M = Mo, W) vdWHs can facilitate water splitting due to their suitable band edges. Therefore, our findings demonstrate two 2D MSi2N4/InS (M = Mo, W) type-II vdWHs with fascinating potentials for photocatalysis. [ABSTRACT FROM AUTHOR]

Abstract Optimal therapeutics to deal with high relapse rates when discontinued is urgent for opioid dependence treatments. Endogenous endomorphin-2 (EM2) level in the central nervous system (CNS) down-regulates obviously after sustained morphine exposure, which suggested that to up-regulate the EM2 level could be a novel method for reinstatement. But the clinical applications of EM2 through conventional administration are limited owing to its short half-life. In our study, we engineered an EM2 gene to achieve the sustained release of EM-2 in CNS by utilizing a signal peptide of mouse growth factor for out-secreting EM2 and a deficient adenovirus as the vector. By intrathecally injecting engineering EM2 gene, a sustained increase of EM2 concentration in the cerebral spinal fluid (CSF) was observed along with a reduction of CPP scores. Also, the activation of astrocytes was suppressed in the hippocampus. In summary, this study provides evidence and reference for using intraspinal gene therapy with a combination of mouse growth factor and EM2 to treat morphine reinstatement. Highlights • We engineered an EM2 gene to achieve the sustained release of EM-2 in CNS. • The phenomenon of morphine reinstatement was improved effectively by intrathecally injecting engineering EM2 gene in rats. • The fusion gene of mouse growth factor and EM2 to treat morphine reinstatement shows promising effects. [ABSTRACT FROM AUTHOR]

Effects of site preference, phase stability and brittle versus ductile behaviors of W, Mo, La and Ce in TiAl have been investigated by using the first-principles calculations. The results show that transition elements W and Mo can effectively stabilize B2 phase except rare earth elements La or Ce. Elastic modulus show that the ductility can be improved for ternary elements addition and there is a plastic transition from intrinsic brittleness to intrinsic ductility with W and Mo addition due to phase transition. The competitive mechanisms between the opening of microcracks and dislocation emission show the increased ductility is mainly due to the energetic dislocation but suppressed cracks. Finally, electronic density of states and charge density show that weakened covalent interactions of TiAl for W, Mo, La and Ce addition are the essential reasons for the transformation from brittleness to ductility. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Site preference, phase stability and brittle vs ductile behaviors have been investigated. • Stacking fault energy and bonding charge density have been investigated to reveal the phase transformation mechanisms. • Cleavage fracture model and slip fracture model were used to give a prediction of brittle to ductile transition mechanism based on Griffith fracture theory. Abstract Site preference, phase stability and brittle vs ductile behaviors of ternary transition elements Cu, Zn and Ag in Al 3 Hf intermetallic are investigated by using of first-principles calculations. It is found that it has a phase transition from D0 23 phase to L1 2 phase for Al 3 Hf due to the strong Al site preference for Cu, Zn and Ag addition. It is shown that the role of activated antiphase boundaries on 〈 1 1 0 〉 (0 0 1) plane is the key factor for the phase transition. Elasticity modulus show that ternary elements can effectively improve the ductility of Al 3 Hf due to the phase transition. Finally, cleavage fracture model and slip fracture model were used to give a prediction of brittle to ductile transition mechanism based on Griffith fracture theory. The energetic results show that the improved ductility is due to the activated dislocation emission but suppressed crack propagation in materials. [ABSTRACT FROM AUTHOR]

The adhesion, stability, electronic structure, and ductility of Al/TiC interfaces with Al, Ti, and C vacancies (Al v , C v and Ti v) are investigated using first-principles calculations. The results show that the adhesion can not be improved significantly by Al v. The adhesion of Al/TiC interfaces with C v and Ti v are stronger than the clean interface. We find the Al atoms will replace the Ti v in the TiC layer for Ti-site with Ti v. Interestingly, the interface will shift from Ti-site into C-site for 75% Ti v. Furthermore, the results of the generalized stacking fault (GSF) energies show that the preferred slip direction is the 〈110〉 direction. Based on the Rice criterion of ductility, it is found that C v will make the interface more brittle. But the ductility of the Al/TiC interface can be improved by Ti v. The theoretical adhesion of Al/TiC interfaces with C v is in good agreement with experimental results. • The adhesion of Al/TiC interfaces with C v and Ti v are stronger than the clean interface. • In the case of Ti-site interface with 75% Ti v , the interface will shift from Ti-site into C-site. • C v will make the interface more brittle. • The ductility of Al/TiC interface can be improved by Ti v. [ABSTRACT FROM AUTHOR]

Van der Waals heterostructures (vdWHs) are effective platforms for exploring various attractive topological phases. Here, based on the low-energy effective k · p model, we propose that the type-III vdWHs, which were previously considered as only belonging to trivial metallic phases, can realize the nontrivial quantum spin Hall (QSH) effect. We reveal that the band inversion of such a QSH phase is attributed to the band alignment of momentum space matching, i.e., the conduction band minimum and valence band maximum located at the same point in momentum space near the Fermi level. Moreover, using first-principles calculations, we show that the Mg(OH)2/Ga2O2 heterobilayer, a typical type-III vdWH with high thermodynamic stability, is an ideal candidate for achieving our strategy. We further calculate the helical gapless edge states and quantized spin Hall conductance, which are visible inside the global bandgap, thus facilitating the experimental observation. Our work offers a promising pathway for realizing the QSH phase in natural materials. [ABSTRACT FROM AUTHOR]

Based on the HRTEM observations about the Al/Al 2.5 Cu 0.5 Zr coherent interface, the effects of Si, Fe and Ti on the adhesion and ductility of the Al 2.5 X 0.5 Zr are investigated using first-principles methods. Six possible interfacial structural models are provided. The interfacial separation obtained by Model V is well in agreement with experimental results. This means Model V is the optimal structure for calculations. The work of adhesion reveals the strongest adhesion of Al/Al 2.5 Cu 0.5 Zr. The unstable stacking fault energies show that the preferred slip direction is 〈 1 1 0 〉 . By analyzing the Rice criterion, the Al/Al 2.5 Zn 0.5 Zr interface has the best ductility. For Si segregation, Al −11 site is favorable for Al/Al 2.5 X 0.5 Zr (X = Cu, Zn) interfaces. The adhesion of these interfaces are reduced due to the segregation of Si. The ductility is improved along 〈 1 1 0 〉 for Al/Al 2.5 X 0.5 Zr (X = Cu, Zn) interfaces. Fe prefers to occupy Zr site in Al/Al 2.5 X 0.5 Zr interfaces. The results demonstrate that the adhesion are improved for all interfaces. The ductility is decreased for Al/Al 2.5 X 0.5 Zr (X = Cu, Zn) interfaces. For Ti segregation, Ti prefer to substitute Zr, comparing with Al and Cu sites, in Al/Al 2.5 X 0.5 Zr interfaces. Ti substitutions will enhance the adhesion with the reduction of ductility. The charge density difference are also used to understand the adhesion and the results are in accordance with the predicted results. [ABSTRACT FROM AUTHOR]

First-principles calculations have been performed to investigate the site preference, generalized stacking fault energies and surface energies of the additive elements M (V, Zr, Mo) in NbCr 2 and M (V, Ta, W) in HfCr 2 . Additionally, the core width and the Peierls stresses of 1/6 〈 1 ‾ 2 1 ‾ 〉 { 1 1 1 } dislocations in both NbCr 2 and HfCr 2 with and without the addition of ternary atoms are firstly investigated within the improved Peierls-Nabarro theory. Our results show that V preferentially occupies Cr site in both compounds, while M (Zr and Mo) occupies the Nb site in NbCr 2 and M (Ta and W) the Hf site in HfCr 2 . Furthermore, when Mo occupies Nb site in NbCr 2 and Ta or W the Hf site in HfCr 2 , the ductility is found to be improved and the Peierls stresses of 1/6 〈 1 ‾ 2 1 ‾ 〉 { 1 1 1 } dislocations decrease for both NbCr 2 and HfCr 2 . [ABSTRACT FROM AUTHOR]

Hybrid iron-based superconductors were synthesized by sonochemical insertion of organic molecules into FeSe layers. High quality of the samples first enabled reliable phase identifications and three structure types were discovered. Structure determination based on neutron data further facilitated the understanding of their structural stability, doping levels and temperature driven structural transitions. [ABSTRACT FROM AUTHOR]

Al 3 Zr precipitates in Al-Cu-Zr alloys are investigated using high-resolution transmission electron microscopy. The results show that Cu can effectively stabilize the L1 2 phase and which may originate from Ref. 〈110〉(001) slip systems activated by Cu, that is in good agreement with our first-principles predictions. Moreover, theoretical calculations show that Zn and Ag has same effect as Cu. The ductility can be improved for stabilized L1 2 phase with Cu, Zn and Ag based on the Pugh’s criterion. Rice and Zhou-Carlsson-Thomson criterions are used to reveal the brittle/ductile mechanism using stacking fault energy. Finally, the electronic density of states show that the brittleness of D0 23 -Al 3 Zr is mainly due to the strong covalent bonding between Al and Zr atoms, and the improved ductility is mainly due to the weakened Zr 4 d and Al 3 p covalent interactions with the addition of Cu, Zn and Ag. [ABSTRACT FROM AUTHOR]

The structural, elastic, lattice dynamic, and electronic properties of intermetallic FeV with B2 ordering under hydrostatic pressure are extensively investigated by using the first-principles calculations within density functional theory. The calculated lattice constant, bulk modulus, magnetic moment, and number of electronic states at the Fermi level at P = 0 GPa are in a good agreement with the previous calculated and experimental results. The elastic moduli show linearly increasing trends with pressure, except shear modulus which shows a linear softening trend. The transverse acoustic (TA) phonon mode propagating along the [110] direction polarized along the [1 1 - 0] direction decreases to be imaginary crossing the critical pressure ∼9.4 GPa, resulting in the structural instability of B2-FeV intermetallic. Comparing the phonon softening with the shear modulus softening, it is suggested that the soft phonon mode dominates the pressure-induced structural instability of B2-FeV. The electronic density of state (DOS) shows that a considerable increase in the number of electronic states at the Fermi level with increasing pressure, and this behavior is consistent with the phonon softening. [ABSTRACT FROM AUTHOR]

Disequilibrium compaction caused by burial or tectonic compression and unloading are the common overpressure mechanisms in foreland basins. However, accurately identifying multiple overpressure origins in such basins is challenging, since it requires distinguishing impact of vertical and horizontal stresses on compaction and overpressure as well as identifying overpressure caused by unloading. This paper proposed a dual compaction factor method (DCFM) to address these issues. A basic DCFM schematic diagram was established through analyzing compaction behaviors before and after tectonic compression to distinguish overpressure derived from two types of disequilibrium compaction and overpressure induced by unloading. In DCFM, a compaction model for mudstone in the foreland basin, which was only controlled by burial, was established based on the relationship between mean deposition rate and compaction factor in weak tectonic compression zone (WTCZ). It was used to determine compaction factor, normal compaction trend (NCT), acoustic transit time, bulk density, and overburden pressure under this compaction condition, as well as to distinguish the impact of burial and tectonic compression on porosity and overpressure at strong tectonic compression zone (STCZ). The DCFM employs mean stress to revise the equivalent depth method (EDM). Pore pressures associated with compaction only derived from burial and derived from both burial and tectonic compression were estimated using conventional EDM and revised EDM, respectively. The total pore pressures were estimated using the Eaton method and were calibrated based on measured ones. Overpressure associated with unloading was determined by comparing total pore pressure with estimated pore pressure generated with disequilibrium compaction. This mode was further applied at two wells from the Sikeshu Sag in the southern Junggar Foreland Basin to reconstruct accurate overpressure profiles with multiple origins, which were consistent with measured pressures and matched well with geological characteristics. Disequilibrium compaction induced by tectonic compression and burial is responsible for overpressure at the Sikeshu Sag. Overpressure transfer is also one of the primary contributors to the excess pressure in the Jurassic and Cretaceous in the Gaoquan anticline at the Sikeshu Sag, with a maximum contribution of 38 %. Plays, consisting of sandstone reservoirs with both transferred overpressure and tectonic-induced overpressure as well as mudstone caprocks with overpressure due to disequilibrium compaction, are favorable for hydrocarbon accumulation. This study can quantify the impact of overpressures with multiple origins on hydrocarbon migration and sealing capacity of caprocks, as well as provide ideas for researching fluid evolution in sedimentary basins. • A compaction model controlled by burial is proposed to distinguish burial and tectonic disequilibrium compaction. • The estimated pore pressure based on mean stress-porosity relationship is consistent with the measurements. • Disequilibrium compaction induced by tectonic compression and burial is primary contributor to overpressure. • The maximum contribution of transferred overpressure in the Jurassic and Cretaceous is 38%. • The impacts of overpressures on hydrocarbon migration and accumulation vary depending on their origins. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) materials with high mobility and suitable direct band gap can be candidates for photoelectric materials. However, some ideal 2D photoelectric materials are easily oxidized in ambient conditions. Herein, we have systematically explored a new 2D ternary layered material by first-principles calculations, named XYO 2 (X=Li, Na; Y=Al, Ga, In). These XYO 2 monolayers possess desirable direct band gaps, revealing fine optical adsorption efficiency due to the adsorption spectra covering visible and ultraviolet light. Importantly, NaAlO 2 host extremely high carrier mobilities of ∼ 1 0 4 cm 2 V − 1 s − 1 , close to that of phosphorene. Furthermore, NaAlO 2 shows outstanding power conversion efficiency of up to 22.8%, meaning that it is a suitable potential donor material. Our results propose potential candidates in the application of photoelectric materials. In addition, LiAlO 2 monolayer with a desirable band gap alignment, can be a possible effective photocatalyst for water splitting within the ultraviolet range. [Display omitted] • Host suitable direct band gap and high carrier mobility. • Possess extremely high PCE for solar cell. • As a photocatalyst for water splitting. [ABSTRACT FROM AUTHOR]

A theoretical model is developed to study the effect of temperature on the refractive index of semiconductors. The model can be used to predict the refractive index at temperatures ranging from near absolute zero to high temperatures. The theoretical results at wavelengths far from the band-edge region agree well with the available experimental results. In the near-band-edge region, the redshift is found to have an obvious effect on the refractive index at elevated temperatures, and a method is provided for considering this effect. Further verification of the model considering the redshift is included and is consistent with the available experimental results. This theoretical method for prediction of temperature-dependent refractive indices of semiconductors may be helpful in the design of the optical devices. [ABSTRACT FROM AUTHOR]

The improved Peierls-Nabarro theory is employed to study the core structure and mobility of $\langle 11\overline {2}0\rangle $ dissociated dislocations of MgB. The generalized stacking fault energy entering the theory is calculated by using first-principle methods. The effects of Mg and B vacancies on the properties of $\langle 11\overline {2}0\rangle $ dislocations are also presented. It is found that Mg vacancy can reduce the antiphase boundary energy and unstable stacking fault energy obviously compared with B vacancy. Peierls stress of MgB with Mg vacancy is about 1/4 ∼1/5 of MgB and MgB with B vacancy. [ABSTRACT FROM AUTHOR]

Highlights: [•] Temperature effects on GPFE of Al, Ni and Cu are studied by first-principles methods. [•] Three typical twinnabilities at different temperature of Al, Ni and Cu are studied. [•] GPFE and twinnabilities of Al, Ni and Cu reduce with increasing temperature. [Copyright &y& Elsevier]

Abstract: The structural, lattice dynamical, and thermodynamical properties of rare-earth intermetallics TbZn and TbCu with CsCl-type structure have been investigated by performing the first principles calculations, in which the density-functional theory (DFT) and density-functional perturbation theory (DFPT) have been employed within the plane-wave basis projector augmented wave (PAW) method. The quasiharmonic approximation (QHA) has been used to estimate the free energies. The phonon frequencies, thermal expansion coefficients, heat capacities, and the elastic moduli at finite temperature are presented. The calculated results for the benchmark metal Cu are in better agreement with the experimental data in comparison with the previous DFT results. Both the elastic moduli and the phonon-dispersion curves demonstrate that the anisotropy of TbZn is larger than that of TbCu. The thermal expansion coefficient of TbZn as a function of temperature is larger than that of TbCu. [Copyright &y& Elsevier]

Abstract: We have investigated the finite temperature elastic properties of AlRE (RE = Y, Tb, Pr, Nd, Dy) with B2-type structures from first principles. The phonon free energy and thermal expansion are obtained from the quasiharmonic approach based on density-functional perturbation theory. The static volume-dependent elastic constants are obtained from energy–strain functions by using the first-principles total-energy method. The comparison between our predicted results and the ultrasonic experimental data for a benchmark material Al provides excellent agreements. At T = 0 K, our calculated values of lattice equilibrium volume and elastic moduli of our calculated AlRE (RE = Y, Tb, Pr, Nd, Dy) intermetallics agree well with the previous theoretical results. The temperature-dependent elastic constants exhibit a normal behavior with temperature, i.e., decrease and approach linearity at higher temperature and zero slope around zero temperature. Furthermore, the anisotropy ratio and sound velocities as a function of temperature have also been discussed. [Copyright &y& Elsevier]

The thermodynamic properties of intermetallic compounds MgSc and AlSc with CsCl-type B2 structure have been studied by performing density functional theory and density functional perturbation theory within the quasi-harmonic approximation in comparison with NiAl. The linear thermal expansion of the lattice, coefficients of thermal expansion, isothermal bulk modulus, phonon dispersions, phonon density of states, and specific heat capacities at constant volume and constant pressure have been obtained. Comparisons have been made with available experimental data and the results of previous calculations, and good agreement has been obtained. Our results show that the thermal expansion of MgSc is larger than that of AlSc. [ABSTRACT FROM AUTHOR]

Abstract: We present the temperature-dependent elastic constants of two ductile rare-earth intermetallic compounds YAg and YCu with CsCl-type B2 structure by using a first-principles approach. The elastic moduli as a function of temperature are predicted from the combination of static volume-dependent elastic constants obtained by the first-principles total-energy method with density-functional theory and the thermal expansion obtained by the first-principles phonon calculations with density-functional perturbation theory. The comparison between our calculated results and the available experimental data for Ag and Cu provides good agreements. In the calculated temperature 0–1000K, the elastic constants of YAg and YCu follow a normal behavior with temperature that those decrease with increasing temperature, and satisfy the stability conditions for B2 structures. The Cauchy pressure for YAg and YCu as a function of temperature is also discussed, and our results mean that YAg and YCu become more ductile while increasing temperature. [Copyright &y& Elsevier]

Abstract: The thermodynamic properties of ductile rare-earth intermetallic compounds YAg and YCu with CsCl-type B2 structure have been studied by performing density-functional theory (DFT) and density-functional perturbation theory (DFPT). To judge that our computational method is reasonable, NiAl has also been investigated in comparisons with experimental data and previous theoretical results. Phonon dispersions and density of states are studied, and it is found that the density of states is mostly composed of Y states both in YAg and YCu at high frequencies. The temperature dependence of various quantities such as the thermal expansion, the isothermal bulk modulus, and the heat capacity is computed under the quasi-harmonic approximation (QHA), and the variation features of these quantities are discussed in detail. From these results, we demonstrate that the intermetallics with better ductility have larger thermal expansions. [Copyright &y& Elsevier]

Abstract: The third-order elastic moduli and pressure derivatives of the second-order elastic constants of novel B2-type AlRE (RE=Y, Pr, Nd, Tb, Dy, Ce) intermetallics are presented from first-principles calculations. The elastic moduli are obtained from the coefficients of the polynomials from the nonlinear least-squares fitting of the energy–strain functions. The calculated second-order elastic constants of AlRE intermetallics are consistent with the previous calculations. To judge that our computational accuracy is reasonable, the calculated third-order constants of Al are compared with the available experimental data and other theoretical results and are found to have good agreements. In comparison with the theory of the linear elasticity, the third-order effects are very important with the finite strains which are lager than approximately 3.5%. Finally, the pressure derivatives have been discussed. [Copyright &y& Elsevier]