Structure evolution during deposition and thermal annealing of amorphous carbon ultrathin films investigated by molecular dynamics simulations.

The evolution of the structure of amorphous carbon (a-C) films during deposition and thermal annealing is of significant interest from both the materials science and application perspectives. However, despite the voluminous literature of studies dealing with the deposition and physical properties of a-C films, basic understanding of the structure evolution due to phase change during film growth and heating is fairly sparse and empirical, presumably due to the lack of high-resolution instruments that can probe structural changes at the atomic and molecular levels in real time. Molecular dynamics (MD) is a powerful computational method for studying atomic/molecular-scale movement and interactions. Thus, the objective of this study was to perform MD simulations that provide insight into changes in the structure of ultrathin a-C films during deposition and annealing. Simulation results reveal a multi-layer film structure, even for a-C films as thin as ~20 Å, the existence of a deposition energy that yields a-C films with the highest sp3 content, the transient and steady-state stages of the structure evolution during annealing at different temperatures, and the changes in the hybridization state (mainly in the bulk layer) encountered during annealing at elevated temperatures. The MD results of this study are of particular importance to applications where the deposition conditions and operation temperature affect the structure and, in turn, the physical properties of ultrathin a-C films used as protective overcoats

The Renaissance of Black Phosphorus

One hundred years after its first successful synthesis in the bulk form in 1914, black phosphorus (black P) was recently rediscovered from the perspective of a two-dimensional (2D) layered material, attracting tremendous interest from condensed matter physicists, chemists, semiconductor device engineers and material scientists. Similar to graphite and transition metal dichalcogenides (TMDs), black P has a layered structure but with a unique puckered single layer geometry. Because the direct electronic band gap of thin film black P can be varied from 0.3 to around 2 eV, depending on its film thickness, and because of its high carrier mobility and anisotropic in-plane properties, black P is promising for novel applications in nanoelectronics and nanophotonics different from graphene and TMDs. Black P as a nanomaterial has already attracted much attention from researchers within the past year. Here, we offer our opinions on this emerging material with the goal of motivating and inspiring fellow researchers in the 2D materials community and the broad readership of PNAS to discuss and contribute to this exciting new field. We also give our perspectives on future 2D and thin film black P research directions, aiming to assist researchers coming from a variety of disciplines who are desirous of working in this exciting research field.Comment: 23 pages, 6 figures, perspective article, appeared online in PNA

Individual Parametric Insurance Product Design

This report presents a design of a parametric insurance product for individual consumers in two neighboring countries Ambernϊa and Palȍmϊnϊa. Unlike traditional insurance, this product issues a predetermined payout to a policyholder when a pre-agreed event has been triggered. By conducting analyses on given health data in the countries, we first projected individual losses and calculated premiums according to gender, age and risk factor information. Then we defined triggering events and modeled the payout scheme for our product. Comprehensive strategies are also provided for marketing and risk mitigation

Optimum resistance analysis and experimental verification of nonlinear piezoelectric energy harvesting from human motions

The complex dynamic behavior of nonlinear harvesters make it difficult to identify the optimum mechanical and electrical parameters for maximum output power, when compared to linear energy harvesting devices. In addition, the chaotic and multi-frequencies characteristics of responses under realistic human motion excitations provide additional challenges for enhancing the energy harvesting performance, such as the traditional frequency domain method being inappropriate for optimum resistance selection. This paper provides detailed numerical and experimental investigations into the influence of resistance on the efficiency of nonlinear energy harvesting from human motions. Numerical simulations under human motions indicate that optimum resistance of a nonlinear harvester can be attained to maximize the power output. Moreover, simulations of linear and nonlinear harvesters under harmonic excitations verify the effectiveness of frequency dominant method to obtain optimum resistance in the absence of a change in the dynamic behavior of the harvester. However, numerical simulations and experiments are the effective methods when the harvester shows complex dynamic characteristics. Experimental measurements of harvested power under different motion speeds and resistances are in agreement to the numerical analysis for the nonlinear harvester. The results demonstrate the effectiveness of the proposed resistance optimization method for nonlinear energy harvesting from human motions.</p

Recovery of Rare Earth Elements from Phosphate Rock by Hydrometallurgical Processes - A Critical Review

Generally, phosphate rock contains about 0.05wt% rare earth elements (REEs) on average. And the world commercial phosphate rock production is estimated to be 250 million tons per year, which makes phosphate rock a potential new REEs resource. However, low content of REEs in phosphate rock leads to the technical challenges and cost overages that hindered the commercial recovery of REEs. In this paper, an overview of achievements aiming at solving the challenges is given. Based on the decomposition processes of phosphate rock by H2SO4, HNO3, HCl, H3PO4, various REEs recovery processes via crystallization, precipitation, solvent extraction and ion exchange methods are systematically reviewed. In H2SO4 processes, REEs are recovered based on the removal of impurities from phosphoric acid and phosphogypsum since the main challenge is the diluted content of REEs in these products. In the case of HCl, HNO3 and H3PO4 processes, REEs entirely transfers into leaching solution and the recovery research are mainly focused on REEs extraction from leaching solutions. For REE extraction from high phosphorus content leaching solutions, crystallization, precipitation, and ion exchange methods are currently inconsiderable due to the high energy consumption, impurity involvement and low efficiency, respectively. Solvent extraction seems to be the potential promising method in terms of its good overall performance. Finally, recommendations to promote the development of REEs recovery technologies from phosphate rock are provided.

Synergistic effects of Yiqi Huazhuo Gushen herbal formula and valsartan on metabolic syndrome complicated with microalbuminuria

Purpose: To study the effects of a combination of Yiqi Huazhuo Gushen formula and valsartan on metabolic syndrome (MetS) complicated with microalbuminuria.Methods: Patients with MetS (100), recruited from Department of the Traditional Chinese Medicine, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital; Department of Integrated Traditional Chinese and Western Medicine, Huashan Hospital, Fudan University; and Department of Endocrinology, Hospital of Integrated Traditional Chinese and Western Medicine in Yueyang, Shanghai University of Traditional Chinese Medicine, were randomly divided into two sets: control group (n = 50) given valsartan treatment, and Chinese herbal medicine (CHF) group (n = 50) given Yiqi Huazhuo Gushen formula in addition to valsartan. Both therapeutic regimens were given once a day for 12 weeks. The parameters measured were conversion rate of microalbuminuria (MA), ratio of urinary albumin to creatinine (UACR), 24- h total volume of urinary protein (24hTP), urinary transferrin, urinary β2 microglobulin, constitutional index (CI), and waist-hip ratio (WHR). Other indices assessed were peak systolic and diastolic pressure (SBP and DBP), mean arterial blood pressure (MABP), fasting plasma glucose (FPG), postprandial 2 h blood glucose (2hPG), glycosylated hemoglobin (GH), steadystate model for insulin resistance (HOMA-IR), total cholesterol (TC), glycerin trilaurate (TG), low density lipoprotein (LDL), and high-density lipoprotein (HDL).Results: All 100 subjects completed the clinical study. The outcome revealed that compared with 10.00 % in controls, the negative conversion of MA reached 28.00 % in the CHF group (p &lt; 0.050). CHF produced reductions in MA, UACR, BMI, 24hTP and urinary β2 microglobulin (p &lt; 0.05). It also led to marked increases in BMI, WHR, SBP, MAP, FPG, 2hPPG, HbA1c and HOMA-IR, and significant decreases in TG (p &lt; 0.05).Conclusion: These results suggest that CHF treatment results in alleviation of microalbuminuria and multiple cardiovascular risk factors in metabolic syndrome complicated with microalbuminuria. These effects correlate with improvements in insulin sensitivity and rectification of abnormal fat distribution.Keywords: Metabolic syndrome, Microalbuminuria, Yiqi Huazhuo Gushen formula, Insulin resistance, Central obesit

Comparative characterization of the PvuRts1I family of restriction enzymes and their application in mapping genomic 5-hydroxymethylcytosine

PvuRts1I is a modification-dependent restriction endonuclease that recognizes 5-hydroxymethylcytosine (5hmC) as well as 5-glucosylhydroxymethylcytosine (5ghmC) in double-stranded DNA. Using PvuRts1I as the founding member, we define a family of homologous proteins with similar DNA modification-dependent recognition properties. At the sequence level, these proteins share a few uniquely conserved features. We show that these enzymes introduce a double-stranded cleavage at the 3′-side away from the recognized modified cytosine. The distances between the cleavage sites and the modified cytosine are fixed within a narrow range, with the majority being 11–13 nt away in the top strand and 9–10 nt away in the bottom strand. The recognition sites of these enzymes generally require two cytosines on opposite strand around the cleavage sites, i.e. 5′-CN11–13↓N9–10G-3′/3′-GN9–10↓N11–13C-5′, with at least one cytosine being modified for efficient cleavage. As one potential application for these enzymes is to provide useful tools for selectively mapping 5hmC sites, we have compared the relative selectivity of a few PvuRts1I family members towards different forms of modified cytosines. Our results show that the inherently different relative selectivity towards modified cytosines can have practical implications for their application. By using AbaSDFI, a PvuRts1I homolog with the highest relative selectivity towards 5ghmC, to analyze rat brain DNA, we show it is feasible to map genomic 5hmC sites close to base resolution. Our study offers unique tools for determining more accurate hydroxymethylomes in mammalian cells

Optimum resistance analysis and experimental verification of nonlinear piezoelectric energy harvesting from human motions

The complex dynamic behavior of nonlinear harvesters make it difficult to identify the optimum mechanical and electrical parameters for maximum output power, when compared to linear energy harvesting devices. In addition, the chaotic and multi-frequencies characteristics of responses under realistic human motion excitations provide additional challenges for enhancing the energy harvesting performance, such as the traditional frequency domain method being inappropriate for optimum resistance selection. This paper provides detailed numerical and experimental investigations into the influence of resistance on the efficiency of nonlinear energy harvesting from human motions. Numerical simulations under human motions indicate that optimum resistance of a nonlinear harvester can be attained to maximize the power output. Moreover, simulations of linear and nonlinear harvesters under harmonic excitations verify the effectiveness of frequency dominant method to obtain optimum resistance in the absence of a change in the dynamic behavior of the harvester. However, numerical simulations and experiments are the effective methods when the harvester shows complex dynamic characteristics. Experimental measurements of harvested power under different motion speeds and resistances are in agreement to the numerical analysis for the nonlinear harvester. The results demonstrate the effectiveness of the proposed resistance optimization method for nonlinear energy harvesting from human motions.</p