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A one-dimensional steady-state model for stimulated Raman backscatter (SRS) and stimulated Brillouin backscatter (SBS) processes in laser-irradiated plasmas is presented. Based on a novel “predictor-corrector” method, the model is capable to deal with broadband scattered light and inhomogeneous plasmas, exhibiting robustness and high efficiency. Influences of the electron density and temperature on the linear gains of both SRS and SBS are investigated, which indicates that the SRS gain is more sensitive to the electron density and temperature than that of the SBS. For the low-density case, the SBS dominates the scattering process, while the SRS exhibits much higher reflectivity in the high-density case. The nonlinear saturation mechanisms and competition between SRS and SBS are included in our model by a phenomenological method. The typical anti-correlation between SRS and SBS versus electron density is reproduced in the model. Calculations of the reflectivities are qualitatively in agreement with the typical results of experiments and simulations.
Advanced Ni8W/Ni12W/Ni8W alloy composite substrates used in YBCO-coated conductors with a strong cube texture and high yield strength have been fabricated, and a CeO2 buffer layer film was successfully deposited on the composite substrates. Through in situ tensile testing coupled with electron backscattered diffraction (EBSD) analysis, the stability of the cube texture of Ni8W/Ni12W/Ni8W alloy composite substrates has been investigated. The stress–strain curve shows that the yield strength (at 0.2% strain) of the composite substrates exceeds 250 Mpa. The orientation of grains and boundaries on the surface of the substrates was almost unchanged, while the strain exceeds 0.2%, which indicated that the composite substrates are adequate for depositing buffer layers and YBCO layers by the reel-to-reel process.
Cigarette smoking is strongly associated with major depressive disorder (MDD). However, any genetic etiology of such comorbidity and causal relations is poorly understood, especially at the genome-wide level.
In the present in silico research, we analyzed summary data from the genome-wide association study of the Psychiatric Genetic Consortium for MDD (n = 191 005) and UK Biobank for smoking (n = 337 030) by using various biostatistical methods including Bayesian colocalization analysis, LD score regression, variant effect size correlation analysis, and Mendelian randomization (MR).
By adopting a gene prioritization approach, we identified 43 genes shared by MDD and smoking, which were significantly enriched in membrane potential, gamma-aminobutyric acid receptor activity, and retrograde endocannabinoid signaling pathways, indicating that the comorbid mechanisms are involved in the neurotransmitter system. According to linkage disequilibrium score regression, we found a strong positive correlation between MDD and current smoking (rg = 0.365; p = 7.23 × 10−25) and a negative correlation between MDD and former smoking (rg = −0.298; p = 1.59 × 10−24). MR analysis suggested that genetic liability for depression increased smoking.
These findings inform the concomitant conditions of MDD and smoking and support the use of self-medication with smoking to counteract depression.
This article presents a brief review of our case studies of data-driven Integrated Computational Materials Engineering (ICME) for intelligently discovering advanced structural metal materials, including light-weight materials (Ti, Mg, and Al alloys), refractory high-entropy alloys, and superalloys. The basic bonding in terms of topology and electronic structures is recommended to be considered as the building blocks/units constructing the microstructures of advanced materials. It is highlighted that the bonding charge density could not only provide an atomic and electronic insight into the physical nature of chemical bond of materials but also reveal the fundamental strengthening/embrittlement mechanisms and the local phase transformations of planar defects, paving a path in accelerating the development of advanced metal materials via interfacial engineering. Perspectives on the knowledge-based modeling/simulations, machine-learning knowledge base, platform, and next-generation workforce for sustainable ecosystem of ICME are highlighted, thus to call for more duty on the developments of advanced structural metal materials and enhancement of research productivity and collaboration.
In the three-phase (pure donor, pure acceptor, and mixed phases) morphologies of organic solar cells, the mixed phases produce an energy cascade that promotes the generation of free carriers. However, how to optimize the content of the mixed phases is a challenging problem. The authors proposed to control different content of mixed phases in DRTB-T and IDIC blends by additive and solvent vapor annealing (SVA). The authors first formed the largest extent amount of mixed phases by the additive cinene (2%) to inhibit the crystallization of DRTB-T and IDIC. And then, different amounts of mixed phases were achieved by further SVA for different times (from 0 to 50 s) to increase the content of pure DRTB-T and IDIC phases. The energetic offsets (ΔE) of pure and mixed phases gradually decrease from 0.529 to 0.477 eV for different content of mixed phases. When ΔE was 0.498 eV, the highest photocurrent density (Jsc) was obtained. The power conversion efficiency was increased from 3.23% (without any treatment) to 8.54%. Therefore, the authors demonstrated that the optimized content of the mixed phases is critical to device performance.
A novel solid-clad-by-liquid method was developed to form a 10-m long by 10-mm wide by 80-μm thick Ni–5 at.% W/Ni–9.3 at.% W/Ni–5 at.% W composite tape. Three deformation routes (cold rolling, cold rolling with intermediate annealing, and cold rolling combined with warm rolling) have been investigated in short Ni–5 at.% W/Ni–9.3 at.% W/Ni–5 at.% W composite substrate. To optimize the dynamic continuous annealing parameters for the long composite substrates, air-cooled and furnace-cooled annealing procedures were compared in short Ni–5 at.% W/Ni–9.3 at.% W/Ni–5 at.% W composite substrates. Improved cube texture of 98.7% in a 10-m long by 10-mm wide by 80-μm thick Ni–5 at.% W/Ni–9.3 at.% W/Ni–5 at.% W composite substrate was achieved via warm rolling deformation at 550 °C and two-step dynamic continuous annealing (750 °C for 1 h followed by 1200 °C for 1 h). The yield strength, Curie temperature, and saturation magnetization of 176 MPa, 324 K, and 18 emu/g, respectively, were obtained.
Employing atomic-scale simulations, the response of a high-angle grain boundary (GB), the soft/hard GB, against external loading was systematically investigated. Under tensile loading close to the hard orientation, strain-induced dynamic recrystallization was observed to initiate through direct soft-to-hard grain reorientation, which was triggered by stress mismatch, inhibited by surface tension from the soft-hard GB, and proceeded by interface ledges. Such grain reorientation corresponds with expansion and contraction of the hard grain along and perpendicular to the loading direction, respectively, accompanied by local atomic shuffling, providing relatively large normal strain of 8.3% with activation energy of 0.04 eV per atom. Tensile strain and residual dislocations on the hard/soft GB facilitate the initiation of dynamic recrystallization by lowering the energy barrier and the critical stress for grain reorientation, respectively.
To examine urban–rural disparity in childhood stunting, wasting and malnutrition at national and subnational levels in Chinese primary-school children in 2010 and 2014.
Data were obtained from two nationwide cross-sectional surveys conducted in 2010 and 2014. Malnutrition was classified using the Chinese national ‘Screening Standard for Malnutrition of Children’.
All twenty-seven mainland provinces and four municipalities of mainland China.
Children aged 7–12 years (n 215 214; 107 741 in 2010 and 107 473 in 2014) from thirty-one provinces.
Stunting, wasting and malnutrition prevalence were 1·9, 12·3 and 13·7 % in 2010, but decreased to 1·0, 9·4 and 10·2 % in 2014, respectively. The prevalence of stunting, wasting and malnutrition in both urban and rural children was higher in western provinces, while lower in eastern provinces. Although the prevalence of wasting and malnutrition was higher in rural children than their urban counterparts, the urban–rural disparity in both wasting and malnutrition decreased from 2010 to 2014 (prevalence OR: wasting, 1·35 to 1·16; malnutrition, 1·50 to 1·27). A reversal occurred in 2014 in several eastern provinces where the prevalence of wasting and malnutrition in urban children surpassed their rural peers. The urban–rural disparity was larger in western provinces than eastern provinces.
The shrinking urban–rural disparity and the reversal in wasting and malnutrition suggest that the malnutrition situation has improved during the post-crisis period, especially in the western provinces. Region-specific policies and interventions can be useful to sustainably mitigate malnutrition in Chinese children, especially in rural areas and the western provinces.
The finite element simulations show that non-equibiaxial residual stresses (RS) can shift the load–depth curve from the unstressed curve and cause elliptical remnant indentation in spherical indentation. Thus the relative load change between stressed and unstressed samples and the asymmetry of elliptical remnant indentation were employed as characteristic parameters to evaluate the magnitude and directionality of RS. Through theoretical and numerical analysis, the effects of RS on indentation load and remnant impression as well as the affect mechanism were systematically discussed. Finally, two equations which could provide foundations for establishing spherical indentation method to evaluate non-equibiaxial RS were obtained.
We incorporate deep learning (DL) into tiled aperture coherent beam combining (CBC) systems for the first time, to the best of our knowledge. By using a well-trained convolutional neural network DL model, which has been constructed at a non-focal-plane to avoid the data collision problem, the relative phase of each beamlet could be accurately estimated, and then the phase error in the CBC system could be compensated directly by a servo phase control system. The feasibility and extensibility of the phase control method have been demonstrated by simulating the coherent combining of different hexagonal arrays. This DL-based phase control method offers a new way of eliminating dynamic phase noise in tiled aperture CBC systems, and it could provide a valuable reference on alleviating the long-standing problem that the phase control bandwidth decreases as the number of array elements increases.
Given the global water challenges, solar-driven steam generation has become a renewed topic recently as an energy-efficient way for clean water production. Here, a hybrid plasmonic structure consisting of a top layer of TiN nanoparticles (NPs) and a bottom layer of mesoporous anodized alumina membrane (AAM) was rationally designed and fabricated. The top TiN NPs with broadband light absorption acted as a plasmonic heating layer, which converted the absorbed light to heat efficiently for interfacial water heating. The AAM acted as the mechanical support layer, guaranteeing the heat isolation and continuous water replenishment. With optimized thickness of the TiN top layer, a solar steam generation efficiency of 87.7% was achieved in this study. This efficiency is comparable or even higher than prior studies. The current work proves the capability of the TiN NPs as an alternative photothermal material.
Interactions of fluvial and eolian processes are prominent in dryland environments and can significantly change Earth surface morphology. Here, we report on sediment records of eolian and fluvial interactions since the last glacial period, in the semiarid area of northwest China, at the limit of the Southeast Asian monsoon. Sediment sequences of last glacial and Holocene terraces of the Yellow River are composed of channel gravels, overlain by flood sands, eolian dunes, and flood loams. These sequences, dated by optically stimulated luminescence, record interlinks between fluvial and eolian processes and their response to climate change. Sedimentologic structures and grain-size analysis show flood loams, consisting of windblown sediment, deposited from floodwater suspended sediment. The gravel and sand were deposited during cold periods. During transitions from cold to warm phases, the river incised, and dunes were formed by deflation of channel and floodplain deposits (>70 and 21–16 ka). Dunes also formed at ~0.8 ka, probably after human intervention. After dune formation, flood loam covered dunes without erosion during peak discharges at the beginning of the subsequent warm period. The fluctuations of the Southeast Asian monsoon as a moisture-transporting agent have perhaps been the driving force for interactions between fluvial and eolian processes in this semiarid environment.
For instrumented spherical indentation, the presence of equibiaxial residual stress in a material will lead the indentation load–depth curve to shift upward or downward. The load differences between the stressed and stress-free curves were used to estimate the equibiaxial residual stress. Using dimensional analysis and finite element simulations, the equibiaxial residual stress was related to the elastic–plastic parameters and the relative load difference at a fixed normalized indentation depth (h/R = 0.1). Based on these expressions, and together with the method for determining elastic–plastic parameters established in our previous work, an integrated method was proposed to estimate the equibiaxial residual stress and elastic–plastic parameters of metals simultaneously via instrumented spherical indentation. This method avoids preknowledge of the yield strength and measuring the contact area. Applications were illustrated on Al 2024, Al 7075, and Ti Grade 5 with introduced stresses. By comparing the results determined by this integrated method with the reference values, the maximum relative error is generally within ±10% for the yield strength, within ±15% for the elastic modulus, and within ±20% for the equibiaxial residual stress.
Two new species of Nilssoniopteris of the order Bennettitales, Nilssoniopteris hamiensis Zhao and Deng, new species and Nilssoniopteris crassiaxis Zhao and Deng, new species, are established from the Xishanyao Formation (Middle Jurassic) of Sandaoling Coal Mine in Hami, Xinjiang, China, based on leaf macromorphology and cuticular features. Nilssoniopteris hamiensis n. sp. is characterized by its varied leaf shapes and trichome bases of 1–4 cells on the abaxial epidermis. Nilssoniopteris crassiaxis n. sp. is characterized by its broad midrib (especially near the leaf base) and trichome bases of 1–3 cells on the abaxial epidermis. Both species possess unique venation patterns that are not only simple and free, but also forked and merged to form closed loops. These anastomosing veins are even more complicated in N. crassiaxis n. sp. in that the veins can fork once, twice, or even three times, the forked veins can later merge with each other or with an adjacent vein to form a closed loop, which may later further disjoin. The generic diagnosis of Nilssoniopteris is thus accordingly emended, particularly in the venation pattern. In addition, the stratigraphic and geographical distributions of all 45 Jurassic Nilssoniopteris species worldwide have been summarized and analyzed to better understand their brief evolutionary history, indicating that Nilssoniopteris might be able to grow not only in subtropical regions as the living cycads are, but also in warm climatic regions.
Ni/Sn–xZn/Ni (x = 1, 5, 9 wt%) joints were used to investigate the effect of Zn content on interfacial reactions during reflow under a temperature gradient. Asymmetrical growth and transformation of intermetallic compounds (IMCs) occurred between the cold and hot end interfaces. Faster IMC growth at the cold end and a more prompt IMC transformation at the hot end in a lower Zn content solder joint were identified due to the more thermomigration-induced Zn and Ni atomic fluxes toward the cold end. The main diffusion species into IMC layers changed from Zn atoms at the early stage to Sn and Ni atoms at the later stage. As a result, the IMC evolution followed (Ni,Zn)3Sn4 → Ni3Sn4 in the Ni/Sn–1Zn/Ni joint, Ni5Zn21 → τ phase → Ni3Sn4 in the Ni/Sn–5Zn/Ni joint, and Ni5Zn21 → τ phase in the Ni/Sn–9Zn/Ni joint along with the reflow time. A higher Zn content could effectively inhibit the dissolution of the hot-end Ni substrate and restrain the growth rate of the cold-end interfacial IMCs.
By reflowing Cu/Sn/Ni ultrafine interconnects under a temperature gradient, a new transient liquid phase (TLP) bonding process was proposed for three-dimensional packaging applications. The evolution of the dominant (Cu,Ni)6Sn5 intermetallic compounds depends strongly on the temperature gradient. The essential cause of such dependence is attributed to the different amounts of Cu and Ni atomic fluxes being introduced into the liquid solder. Under the coupling effect of thermomigration and Cu–Ni cross-interaction, the total atomic flux of Cu and Ni is promoted. As a result, the growth of dense (Cu,Ni)6Sn5 is significantly accelerated and the formation of Cu3Sn is eliminated. The new TLP bonding process consumes only a limited amount of the Ni substrate, but much more from the Cu substrate. The mechanism for the new TLP bonding process is discussed and experimentally verified in this study.
We aimed to examine the contribution of blood lipids to the association between BMI and blood pressure (BP) in children with overweight and obesity. Data were collected in elementary and high schools of Chaoyang District, Beijing, China in 2012. Participants’ weight, height, BP and fasting plasma lipid profile were measured by standard protocols. Mediation analysis was used to examine the mediation role of blood lipids on the relation between BMI and BP, with age included as a covariate. We found that in boys 8·29 % (mediation effect=0·106, P=0·012) of the association between BMI and systolic BP was mediated through TAG. TAG mediated 12·53 % (mediation effect=0·093, P=0·018) and LDL-cholesterol mediated 7·75 % (mediation effect=0·57, P=0·046) of the association between BMI and diastolic BP was mediated by TAG and LDL-cholesterol, respectively. However, blood lipids did not show the mediation effect in girls. Our findings suggested that there was a sex difference in the contribution of blood lipids to the association between BMI and BP. Controlling TAG or LDL-cholesterol may be beneficial for reducing the risk of the BMI-related high BP in overweight boys; however, this outcome is not the case when controlling TAG or LDL-cholesterol in girls. This study may provide clues to explore the underlying mechanism of the association between obesity and hypertension.