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Metal-halide perovskite solar cells (PSCs) have become a promising candidate for photovoltaic applications. Current popular organic hole conductors for highly efficient PSCs bring cost and stability issues, which hinder the commercialization of the PSCs. Hole-conductor-free PSCs are attracting great interest because they eliminate the adverse effects of organic hole conductors by transporting holes in the perovskite itself. In this article, we summarize recent progress in conventional, inverted, and printable mesoscopic hole-conductor-free PSCs. Specifically, we emphasize the stunning stability and scale-up manufacturing of printable hole-conductor-free PSCs, discussing their potential from laboratory to market. The causes for hole-conductor-free PSCs’ current low efficiency are also discussed, and are primarily ascribed to energy-level alignment and interface recombination. We believe that the efficiencies of hole-conductor-free PSCs can be enhanced to be comparable with hole-conductor-containing PSCs by interface modification and material design.
A critical branching process with immigration which evolves in a random environment is considered. Assuming that immigration is not allowed when there are no individuals in the population, we investigate the tail distribution of the so-called life period of the process, i.e. the length of the time interval between the moment when the process is initiated by a positive number of particles and the moment when there are no individuals in the population for the first time.
Psychiatric disorders are a group of complex psychological syndromes with high prevalence. Recent studies observed associations between altered plasma proteins and psychiatric disorders. This study aims to systematically explore the potential genetic relationships between five major psychiatric disorders and more than 3,000 plasma proteins.
The genome-wide association study (GWAS) datasets of attention deficiency/hyperactive disorder (ADHD), autism spectrum disorder (ASD), bipolar disorder (BD), schizophrenia (SCZ) and major depressive disorder (MDD) were driven from the Psychiatric GWAS Consortium. The GWAS datasets of 3,283 human plasma proteins were derived from recently published study, including 3,301 study subjects. Linkage disequilibrium score (LDSC) regression analysis were conducted to evaluate the genetic correlations between psychiatric disorders and each of the 3,283 plasma proteins.
LDSC observed several genetic correlations between plasma proteins and psychiatric disorders, such as ADHD and lysosomal Pro-X carboxypeptidase (p value = 0.015), ASD and extracellular superoxide dismutase (Cu-Zn; p value = 0.023), BD and alpha-N-acetylgalactosaminide alpha-2,6-sialyltransferase 6 (p value = 0.007), MDD and trefoil factor 1 (p value = 0.011), and SCZ and insulin-like growth factor-binding protein 6 (p value = 0.011). Additionally, we detected four common plasma proteins showing correlation evidence with both BD and SCZ, such as tumor necrosis factor receptor superfamily member 1B (p value = 0.012 for BD, p value = 0.011 for SCZ).
This study provided an atlas of genetic correlations between psychiatric disorders and plasma proteome, providing novel clues for pathogenetic and biomarkers, therapeutic studies of psychiatric disorders.
A detailed electron backscatter diffraction (EBSD) characterization was utilized to investigate abnormal grain growth behavior of nanocrystalline (NC) Au films constrained by a flexible substrate under cyclic loading. Abnormally grown grains (AGGs) in front of about 15 fatigue cracks were picked out to investigate the grain reorientation behavior during abnormal grain growth in the fatigue crack tip in the cyclically deformed thin films. It shows that the AGGs exhibited 〈001〉 orientation along the loading direction, whereas grains grown far away from fatigue cracks had no significant texture change. The cyclic cumulative shear strain was found to play a key role in grain reorientation. A lattice rotation model was proposed to elucidate the grain reorientation mechanism during abnormal grain growth. Such grain reorientation behavior of NC metals was found to provide an intrinsic resistance of the NC metals to fatigue damage.
Vision and language are two fundamental capabilities of human intelligence. Humans routinely perform tasks through the interactions between vision and language, supporting the uniquely human capacity to talk about what they see or hallucinate a picture on a natural-language description. The valid question of how language interacts with vision motivates us researchers to expand the horizons of computer vision area. In particular, “vision to language” is probably one of the most popular topics in the past 5 years, with a significant growth in both volume of publications and extensive applications, e.g. captioning, visual question answering, visual dialog, language navigation, etc. Such tasks boost visual perception with more comprehensive understanding and diverse linguistic representations. Going beyond the progresses made in “vision to language,” language can also contribute to vision understanding and offer new possibilities of visual content creation, i.e. “language to vision.” The process performs as a prism through which to create visual content conditioning on the language inputs. This paper reviews the recent advances along these two dimensions: “vision to language” and “language to vision.” More concretely, the former mainly focuses on the development of image/video captioning, as well as typical encoder–decoder structures and benchmarks, while the latter summarizes the technologies of visual content creation. The real-world deployment or services of vision and language are elaborated as well.
Nanostructures are considered to have great potential and are widely used in energy storage and sensing devices, and atomic layer deposition (ALD) is of great help for better nanostructure fabrications. ALD can help to preserve the original properties of materials, and, meanwhile, the excellent film quality, nanoscale precise thickness control, and high conformality also play important role in fabrication process. To enhance the performance of energy storage and sensor devices, ALD has been used in directly fabricating active nanostructures, depositing protective passivation layers, etc. ALD is a convenient technique which has been widely engaged in energy-related fields including electrochemical conversion and storage, as well as in sensor and biosensors. The related research interest is increasing significantly. In this review, we summarize some of the latest works on ALD for batteries, supercapacitors, and sensors, and demonstrate the benefits of ALD comprehensively. In these devices, different materials are deposited by ALD under different conditions to achieve better battery performance, higher supercapacitor capacitance, and higher sensitivity. This review fully presents the strengths of ALD and its application in energy storage and sensing devices and proposes the future prospects for this rapidly developing technology.
Hepatitis C virus (HCV) infection was frequent in human immunodeficiency virus (HIV) patients in Yunnan province. We studied the epidemic characteristics of HCV in HIV/HCV co-infected patients. Serum from 894 HIV-1 patients was collected, together with basic information and biochemical features. All samples were infected with HIV through injecting drug users (IDUs) and sexual transmission (ST). The NS5B gene was amplified and sequenced to affirm HCV genotype. In total, 202 HIV patients were co-infected with HCV, and most (81.19%) of co-infected patients were IDUs. Genotype 3b was predominant (37.62%) in these samples, and its frequency was similar in patients with IDU and ST. The frequencies of genotypes 1a, 1b, 3a, 6a, 6n, 2a and 6u were 3.96%, 16.34%, 23.76%, 6.93%, 10.40%, 0.50% and 0.50%, respectively. However, genotype 3a showed significantly different frequency in HCV patients with IDU and ST (P = 0.019). When HCV patients were divided into subgroups, the haemoglobin (HGB) level was significantly higher in patients with genotype 3a than in patients with 3b (P = 0.033), 6a (P = 0.006) and 6n (P = 0.007), respectively. Although no difference existed among HCV subgroups, HIV-viral load was identified to be positively correlated with the HGB level and CD4+ cells when dividing HCV/HIV co-infected persons into male and female groups. In conclusion, genotype 3b was the predominant HCV genotype in Yunnan HIV/HCV co-infected persons. The HGB level was higher in patients with genotype 3a than others. HIV-viral load was positively correlated with the HGB level and CD4+ cells in the male or female HCV-infected group.
In this paper, possible coupling configurations of a four-plate capacitive power transfer system are studied by varying the combinations of its input and output ports. A voltage source is applied between two of the four plates, and a load is connected to the other two to form different circuit topologies. A mathematical model based on a 4 × 4 mutual capacitance matrix is established for equidistantly placed four identical metal plates. Based on the proposed model, four separate circuit topologies are identified and analysed in detail and described in a general form. The electric field distributions of the coupling configurations are simulated by ANSYS Maxwell. The theoretical modeling and analysis are then verified by a practical system, in which four aluminum plates of 300 mm × 300 mm are used and placed with a gap of 10 mm between adjacent plates. The experimental results show that the measured output voltage and power under the four coupling configurations are in good agreement with the theoretical results. It has found that the voltage gain is the highest when the two inner plates are connected to the source, and this coupling configuration also has the lowest leakage electric field.
l-Carnitine is essential for mitochondrial β-oxidation and has been used as a lipid-lowering feed additive in humans and farmed animals. d-Carnitine is an optical isomer of l-carnitine and dl-carnitine has been widely used in animal feeds. However, the functional differences between l- and d-carnitine are difficult to study because of the endogenous l-carnitine background. In the present study, we developed a low-carnitine Nile tilapia model by treating fish with a carnitine synthesis inhibitor, and used this model to investigate the functional differences between l- and d-carnitine in nutrient metabolism in fish. l- or d-carnitine (0·4 g/kg diet) was fed to the low-carnitine tilapia for 6 weeks. l-Carnitine feeding increased the acyl-carnitine concentration from 3522 to 10 822 ng/g and alleviated the lipid deposition from 15·89 to 11·97 % in the liver of low-carnitine tilapia. However, as compared with l-carnitine group, d-carnitine feeding reduced the acyl-carnitine concentration from 10 822 to 5482 ng/g, and increased lipid deposition from 11·97 to 20·21 % and the mRNA expression of the genes involved in β-oxidation and detoxification in the liver. d-Carnitine feeding also induced hepatic inflammation, oxidative stress and apoptosis. A metabolomic investigation further showed that d-carnitine feeding increased glycolysis, protein metabolism and activity of the tricarboxylic acid cycle and oxidative phosphorylation. Thus, l-carnitine can be physiologically utilised in fish, whereas d-carnitine is metabolised as a xenobiotic and induces lipotoxicity. d-Carnitine-fed fish demonstrates increases in peroxisomal β-oxidation, glycolysis and amino acid degradation to maintain energy homeostasis. Therefore, d-carnitine is not recommended for use in farmed animals.
The wake structure of an incompressible, conducting, viscous fluid past an electrically insulating sphere affected by a transverse magnetic field is investigated numerically over flow regimes including steady and unsteady laminar flows at Reynolds numbers up to 300. For a steady axisymmetric flow affected by a transverse magnetic field, the wake structure is deemed to be a double plane symmetric state. For a periodic flow, unsteady vortex shedding is first suppressed and transitions to a steady plane symmetric state and then to a double plane symmetric pattern. Wake structures in the range
without a magnetic field have a symmetry plane. An angle
exists between the orientation of this symmetry plane and the imposed transverse magnetic field. For a given transverse magnetic field, the final wake structure is found to be independent of the initial flow configuration with a different angle
. However, the orientation of the symmetry plane tends to be perpendicular to the magnetic field, which implies that the transverse magnetic field can control the orientation of the wake structure of a free-moving sphere and change the direction of its horizontal motion by a field–wake–trajectory control mechanism. An interesting ‘reversion phenomenon’ is found, where the wake structure of the sphere at a higher Reynolds number and a certain magnetic interaction parameter (
) corresponds to a lower Reynolds number with a lower
value. Furthermore, the drag coefficient is proportional to
for weak magnetic fields or to
for strong magnetic fields, where the threshold value between these two regimes is approximately
In order to reveal the quantitative relationship between fatigue crack deflection path and cross-sectional grain boundary (GB) arrangement of metallic nanolayered composites (NLCs), a stochastic model was established based on the interface-dominant fatigue damage for the ultrafine-scale NLCs. The model indicates that the crack deflection length decreases with decreasing GB arrangement deviation and grain size of constituent layers. The observation and quantitative analysis of fatigue cracking behavior of the Cu/W multilayers with a layer thickness of 5 and 20 nm was conducted to verify the model.
Fatigue performance of metallic nanolayered composites (NLCs) has been gaining more and more attention due to the rapid development in the field of both micro-electro-mechanical systems and high-performance engineering structure materials and the increasing demand for long-term fatigue reliability. Metallic NLCs have exhibited different damage behaviors due to the effect of high-density heterogeneous interface compared with bulk materials and thin metal films. In this review paper, the cyclic deformation damage behavior, fatigue cracking feature, and fatigue properties of some metallic NLCs are reviewed. Effects of length scales, including layer thickness and grain size, on fatigue damage behaviors of the NLCs are revealed, and the transition of the fatigue cracking behavior and the corresponding damage mechanism are discussed. Then, the fatigue properties of some typical metallic NLCs are presented and compared with that of bulk materials and metal thin films. The effect of interface type and grain boundary alignment is also discussed to correlate with fatigue cracking resistance of the NLCs. Finally, some prospective research topics on fatigue performance of metallic NLCs are addressed.
Fatigue properties of Mo/W multilayers with individual layer thickness (λ) of 5, 20, 50 and 100 nm on flexible polyimide substrates were investigated. The experimental results show that the fatigue resistance increases with decreasing λ from 100 nm to 20 nm, and reaches the maximum at λ=20 nm, and then decreases when further decreasing λ. Fatigue cracks of Mo/W multilayers with different λ were found to propagate along columnar grain boundary in the out-of-plane direction and along the boundary of cluster structures. The enhanced fatigue resistance is attributed to the larger cluster inclination angles and the more tortuous in-plane cracking paths.
When the Galileo number is below the first bifurcation, the instability and transition of a vertical ascension or the fall of a free sphere affected by a vertical magnetic field are investigated numerically. A compact model is used to explain that the magnetic field can destabilize the fluid–solid system. When the interaction parameter exceeds a critical value, the sphere trajectory is transitioned from a steady vertical trajectory to a steady oblique one. Furthermore, the trajectory will remain vertical at a sufficiently large magnetic field because of a double effect of the magnetic field on the fluid–solid system. Under the influence of an external vertical magnetic field, four wake patterns at the rear of the sphere are found and the physical behaviour of the free sphere is independent of the density ratio. The wake or trajectory of the free sphere is only determined by the Galileo number
and the interaction parameter
. A close relationship between the streamwise vorticity and the sphere motion is found. An interesting ‘agglomeration phenomenon’ is also found, which shows that the vertical velocities are agglomerated into a point for a certain magnetic field regardless of the Galileo number and satisfy a scaling law
. The principal results of the present work are summarized in a map of regimes in the
Manganese sulfides (MnS) with a diversity of well-defined morphologies and phases have been successfully synthesized by the solvothermal approach. The phase structure and morphology of MnS could readily be tuned by adjusting the sulfur sources and solvents. Hollow γ-MnS spheres were obtained by treating L-cysteine and manganese source in ethylene glycol (EG) at 200 °C for 2 h, whereas a replacement of the mixture solvent by EG and deionized water yields the hierarchical flower-like γ-MnS. γ-MnS tubes were also produced under the same condition by using diethylene glycol and deionized water as solvents. When thioacetamide used as the sulfur source and oleylamine used as the solvent, monodisperse α-MnS nanoparticles with the mean diameter of 17 nm could be synthesized successfully. The phase structures, sizes, and morphologies of samples were investigated in detail by powder X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The UV-vis absorption peak and the width of band gap with different morphologies of the as-prepared MnS were measured. The samples described in this paper are promising to be utilized in solar cells, biomedicine, short wavelength electronic devices, photocatalysis, and other fields.
With the development of remote sensing and geostatistical technology, complex environmental variables are increasingly easily quantified and applied in modelling soil organic carbon (SOC). However, this emphasizes data redundancy and multicollinearity problems adding to the difficulty in selecting dominant influential auxiliary variables and uncertainty in estimating SOC stocks. The current paper considers the spatial characteristics of SOC density (SOCD) to construct prediction models of SOCD on the basis of reducing the data dimensionality and complexity using the principal component analysis (PCA) method. A total of 260 topsoil samples were collected from Chahe town, China. Eight environmental variables (elevation, aspect, slope, normalized difference vegetation index, normalized difference moisture index, nearest distance to construction area and road, and land use degree comprehensive index) were pre-analysed by PCA and then extracted as the main principal component variables to construct prediction models. Two geostatistical approaches (ordinary kriging and ordinary co-kriging) and two regression approaches (ordinary least squares and geographically weighted regression (GWR)) were used to estimate SOCD. Results showed that PCA played an important role in reducing the redundancy and multicollinearity of the auxiliary variables and GWR achieved the highest prediction accuracy in these four models. GWR considered not only the spatial characteristics of SOCD but also the related valuable information of the auxiliary attributes. In summary, PCA-GWR is a promising spatial method used here to predict SOC stocks.
Based on the data from the Next Generation Virgo cluster Survey (NGVS), we statistically study the photometric properties of globular clusters (GCs), ultra-compact dwarfs (UCDs) and dwarf nuclei in the Virgo core (M87) region. We found an obvious negative color (g - z) gradient in GC system associate with M87, i.e. GCs in the outer regions are bluer. However, such color gradient does not exist in UCD system, neither in dwarf nuclei system around M87. In addition, we found that many UCDs are surrounded by extended, low surface brightness envelopes. The dwarf nuclei and UCDs show different spatial distributions from GCs, with dwarf nuclei and UCDs (especially for the UCDs with visible envelopes) lying at larger distances to the Virgo center. These results support the view that UCDs (at least for a fraction of UCDs) are more tied to dwarf nuclei than to GCs.
We consider a discrete-time branching random walk in the boundary case, where the associated random walk is in the domain of attraction of an α-stable law with 1 < α < 2. We prove that the derivative martingale Dn converges to a nontrivial limit D∞ under some regular conditions. We also study the additive martingale Wn and prove that n1/αWn converges in probability to a constant multiple of D∞.