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We present reflectance transformation imaging (RTI) as a documentation tool for visualizing and recording the treatment of coins. RTI—a computational photograph technique that calculates light positions—allows interactive relighting for vision. Virtual light enhances surface details for examining morphological difference. By applying Dome RTI method, stages of conservation treatment were recorded to enhance the overall characteristic features of the relief upon the coin surface, and then detect and identify weathered characters. Patina removal and consolidation were documented along with the original state; a significant difference in the coin’s surface was observed using different filters of the RTI viewer. Specular enhancement and normal visualization results were most effective for detecting the change in morphology and reflectivity. Microscopic RTI was applied to visualized minimal changes of characters between treatment stages. Character “常” of coin 1 showed changes in the cleaning of dirt and removal of alumina powder. The character “元” of coin 3, originally covered by a thick patina, revealed clear strokes using virtual relighting through RTI. These documentation images indicate that RTI is a promising tool to support manual recording of conservation stages and, furthermore, allow detection of areas difficult to visualize through the human eye.

The power conversion efficiency of CsPbI

Defect passivation has become essential in improving efficiency and stability in perovskite solar cells. Here, we report the use of (α-methylguanido)acetic acid, also known as creatine, as a passivation molecule. It is employed both as an additive and as a surface passivation layer of perovskite thin films, given its multiple functional groups, which could address different defect sites, and its size, which could inherently affect the material structure. We prove that the surface passivation is more efficiently working by removing vulnerable defects on the surface. Hole and electron defect densities were reduced, leading to the highest power conversion efficiency of 22.6%. In addition, it can effectively protect the perovskite thin film and improve the operational stabilities in high thermal (85 °C) and humid conditions (50% relative humidity), suggesting a strong stability of the surface passivation layer.

This work presents digital imaging technology as a tool for studying artists’ brushstroke patterns and painting techniques. Digital imaging analysis performed using reflectance transformation imaging (RTI) and three-dimensional (3D) scanning was used to observe the morphological textures of brushstrokes formed on the painted surface; this provided a “digital fingerprint” to indicate an individual artist’s specific characteristics. A model specimen was produced to examine the relationship between paint and painting tools. For painting tools, twelve types of brushes were chosen from the artist’s studio. The results revealed distinctive features among the different types of brushes. The model specimen was then further compared with the artist’s works and a replicated painting was also produced for comparison with one of the original works. The overall result provided information about similar patterns corresponding to the types of brushes the artist used for the model specimen and paintings. Distinctive painting pattern features were detected in the replica, although it was painted using the same material and type of brush.

With the unprecedented development of perovskite solar cells (PSCs), various interlayers have been investigated. Interlayers have diverse roles in shifting the energy levels, attracting and extracting charges, and passivating surface traps. These can improve the stability of PSCs, as well as their power conversion efficiency (PCE). In this study, a small molecular self-assembled monolayer (2-[carbamimidoyl(methyl)amino]acetic acid) is introduced on a SnO2 layer. The acetic acid is known as creatine, existing naturally in the human body. It is eatable and dosed by athletes for energy. Due to its structural properties, creatine can be anchored on a SnO2 layer, thus, it can strengthen the charge extraction from a perovskite layer by forming interface dipoles and reducing the work function. Also, it can passivate the defects in the perovskite layer. These properties are comprehensively investigated via various experimental techniques. With the creatine layer as a cathode interfacial layer on the SnO2 layer, the PSC employing a triple cation-based perovskite achieves the highest PCE of 20.8% and retained 90% of it after 50 days. Furthermore, 22.1% of PCE is obtained from the formamidinium-based perovskite. This report represents an interesting application of creatine as an interlayer in PSCs and suggests the possible application of other essential amino acids.

Defects and energy offsets at the bulk and heterojunction interfaces of perovskite are detrimental to the efficiency and stability of perovskite solar cells (PSCs). Herein, we designed an amphiphilic π-conjugated ionic compound (QAPyBF

Organic photovoltaics (OPVs) are a promising next-generation photovoltaic technology with great potential for wearable and transparent device applications. Over the past decades, remarkable advances in device efficiency close to 20 % have been made for bulk heterojunction (BHJ)-based OPV devices with long-term stability, and room for further improvements still exists. In recent years, ancillary components have been demonstrated as effective in improving the photovoltaic performance of OPVs by controlling the optoelectronic and morphological properties of BHJ blends. Herein, an updated understanding of polymer-based blend OPVs is provided, and the role and impact of ancillary components in various blend systems are categorized and discussed. Lastly, a strategic perspective on the ancillary components of blend-based OPVs for commercialization is provided.

There is an urgent demand to improve the efficiency and the color purity of the environment-friendly quantum dots (QDs), which can be used in wide color gamut (WCG) displays. In this study, we optimized the reaction conditions for the InP core synthesis and the ZnSe/ZnS multishell growth on the core. As a result, remarkable improvements were achieved in the photoluminescence quantum yield (PL QY, 95%) and the full width at half-maximum (fwhm, 36 nm), with perfectly matched wavelength (528 nm) for the green color in WCG displays. Injection of the phosphorus precursor at a mild temperature during the InP core synthesis reduced the size distribution of the core to 12%, and the shell growth performed at a high temperature significantly enhanced the crystallinity of the thick passivating layer. We also investigated the photophysical properties, particularly the energy trap distributions and trap state emissions of the InP-based QDs with different shell structures. The time-resolved and temperature-dependent PL...

In this paper we present RTI as a documentation tool for visualizing and recording the treatment of coins. RTI, a computational photograph technique based on raking light images, allows interactive re-lighting for vision. Virtual light enhances surface details to examine morphological difference. Stages of conservation treatment were recorded to enhance characteristic features of the relief upon the coin surface and detect and identify weathered characters. Patina removal and consolidation were documented along with the original state. A significant difference in normal and surface texture was observed using RTI viewer and filters. Specular enhancement and normal visualization results were effective for detecting the change of morphology and reflectivity. Characters submersed by thick patina were revealed in Coin 3. Two hidden characters were detected as ‘元’ and ‘訓’. Another illegible character which was previously not regarded as an inscription was discovered. Also, verification of each treatment stage was done to examine whether any foreign material was sufficiently removed. These documentation images indicate that RTI is a promising tool to support manual recording and furthermore allow detection of areas difficult to visualize through the human eye.

Background: While previous studies have examined the relationships between social support and healthcare accessibility among ethnic minority populations, studies on Korean Americans remain scarce. Therefore, this study aims to assess the relationship between Korean Americans’ mental health, accessibility to healthcare, and how they perceive their level of social support during the COVID-19 pandemic. Result: We distributed online surveys to Korean Americans from May 24, 2020 to June 14, 2020, generating 790 responses from participants residing in 42 states. Binary Logistic and Ordinary Least Square regression analyses revealed that poor mental health was associated with language barriers inhibiting Korean Americans’ access to COVID-19-related information. Their perceived social support from family members and close friends was positively associated with mental health. Conclusion: Our findings recommend that equipping community healthcare services with translators or interpreters is necessary. Additionally, health practitioners and staff should be trained to utilize telehealth tools to effectively treat individuals with mental health problems. American policymakers and healthcare professionals need to understand and address the unique hardships Korean Americans experience amid COVID-19.

We investigated the dependence of the spectral diffusion and blinking behaviors of indium phosphide (InP) based core/shell/shell quantum dots (QDs) on their mid-shell compositions. We synthesized two types of core/shell/shell QDs having different mid-shell structures by controlling the shell thickness, the total sizes, and the selenium to sulfur ratios. The QDs with a discrete mid-shell (DS-QDs) exhibited a higher photoluminescence (PL) quantum yield (QY) and a narrower PL linewidth than the QDs with a gradient mid-shell (GS-QDs). By analyzing X-ray diffraction (XRD) patterns, and Raman spectra, we found that GS-QDs showed a larger lattice mismatch between the core and the shell than DS-QDs. Also, the spectral diffusion, PL blinking, Auger ionization efficiencies, and the lifetime blinking behavior on single QDs revealed that DS-QDs were nearly unaffected by the defect traps.

Background Portion control is a useful component of weight reduction interventions and meal replacement (MR) plans represent a promising strategy for portion control. Research performed with pooled data on the effect of MR plans according to various characteristics of MR interventions remains scarce. Objective Our aim was to assess the effects of MR-based diets compared with food-based diets on weight loss, according to calorie-restriction types and energy intake proportions from MR. Methods Electronic databases (Cochrane Central Register of Controlled Trials, PubMed, Embase, and Research Information Sharing Service) were searched for randomized controlled trials on weight loss results of MR-based calorie-restricted diets compared with food-based calorie-restricted diets from January 2000 to May 2020. Standardized mean differences (Hedges' g) from all study outcomes were calculated using a random-effects model. Heterogeneity was quantified by Q test and I2. Publication bias was assessed using a funnel plot and a trim and fill method. Both interventions (MR and control) were separated into very-low-energy diets and low-energy diets (LEDs). A meta-analysis of variance was conducted by dividing patient-related factors and treatment-related factors into subgroups. In multivariable meta-regressions, background variables were selected first, after which main independent variables were included. Results Twenty-two studies involving 24 interventions and 1,982 patients who were overweight or obese were included. The effect size in which MR-based LED was compared with food-based LED for weight loss was small, favoring MR (Hedges' g = 0.261; 95% CI 0.156 to 0.365; I2 = 21.9; 95% CI 0.0 to 53.6). Diets including ≥60% of total daily energy intake from MR had a medium effect size favoring MR with regard to weight loss among the groups (Hedges' g = 0.545; 95% CI 0.260 to 0.830; I2 = 42.7; 95% CI 0.0 to 80.8). Conclusions The effect of MR-based LED on weight loss was superior to the effect of food-based LED, and receiving ≥60% of total daily energy intake from MR had the greatest effect on weight loss.