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PDF file - 186K, Glycans with differential levels in serum from DU, DGC and IGC relative to NAG according to ANOVA analysis. Mean difference as well as 95% confidence intervals are displayed. Glycans with a statistically significant p-value (P

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Promotion of good mental health, prevention, and early intervention before/at the onset of mental disorders improve outcomes. However, the range and peak ages at onset for mental disorders are not fully established. To provide robust, global epidemiological estimates of age at onset for mental disorders, we conducted a PRISMA/MOOSE-compliant systematic review with meta-analysis of birth cohort/cross-sectional/cohort studies, representative of the general population, reporting age at onset for any ICD/DSM-mental disorders, identified in PubMed/Web of Science (up to 16/05/2020) (PROSPERO:CRD42019143015). Co-primary outcomes were the proportion of individuals with onset of mental disorders before age 14, 18, 25, and peak age at onset, for any mental disorder and across International Classification of Diseases 11 diagnostic blocks. Median age at onset of specific disorders was additionally investigated. Across 192 studies (n = 708,561) included, the proportion of individuals with onset of any mental disorders before the ages of 14, 18, 25 were 34.6%, 48.4%, 62.5%, and peak age was 14.5 years (k = 14, median = 18, interquartile range (IQR) = 11–34). For diagnostic blocks, the proportion of individuals with onset of disorder before the age of 14, 18, 25 and peak age were as follows: neurodevelopmental disorders: 61.5%, 83.2%, 95.8%, 5.5 years (k = 21, median=12, IQR = 7–16), anxiety/fear-related disorders: 38.1%, 51.8%, 73.3%, 5.5 years (k = 73, median = 17, IQR = 9–25), obsessive-compulsive/related disorders: 24.6%, 45.1%, 64.0%, 14.5 years (k = 20, median = 19, IQR = 14–29), feeding/eating disorders/problems: 15.8%, 48.1%, 82.4%, 15.5 years (k = 11, median = 18, IQR = 15–23), conditions specifically associated with stress disorders: 16.9%, 27.6%, 43.1%, 15.5 years (k = 16, median = 30, IQR = 17–48), substance use disorders/addictive behaviours: 2.9%, 15.2%, 48.8%, 19.5 years (k = 58, median = 25, IQR = 20–41), schizophrenia-spectrum disorders/primary psychotic states: 3%, 12.3%, 47.8%, 20.5 years (k = 36, median = 25, IQR = 20–34), personality disorders/related traits: 1.9%, 9.6%, 47.7%, 20.5 years (k = 6, median = 25, IQR = 20–33), and mood disorders: 2.5%, 11.5%, 34.5%, 20.5 years (k = 79, median = 31, IQR = 21–46). No significant difference emerged by sex, or definition of age of onset. Median age at onset for specific mental disorders mapped on a time continuum, from phobias/separation anxiety/autism spectrum disorder/attention deficit hyperactivity disorder/social anxiety (8-13 years) to anorexia nervosa/bulimia nervosa/obsessive-compulsive/binge eating/cannabis use disorders (17-22 years), followed by schizophrenia, personality, panic and alcohol use disorders (25-27 years), and finally post-traumatic/depressive/generalized anxiety/bipolar/acute and transient psychotic disorders (30-35 years), with overlap among groups and no significant clustering. These results inform the timing of good mental health promotion/preventive/early intervention, updating the current mental health system structured around a child/adult service schism at age 18.

최근 검·경수사권 조정에 관한 정부의 입장에는 자치경찰제 운영에 관한 내용도 함께 수록되었다. 자치경찰제는 과거로부터 논의가 지속되어 왔지만, 중앙정부에 집중되어 있던 경찰행정의 권한을 지방에 분산시켜 지역주민의 입장을 반영하고 지역사회의 실정에 맞는 치안서비스와 대민서비스를 제공하기 위한 노력의 성과는 쉽게 나타나지 않았다. 현 정부의 등장과 함께 권력기관에 대한 개혁의 바람이 불기 시작하였고, 그동안 불공정 사례와 권한남용의 상처를 남긴 검찰권력에 대한 개혁의 일환으로 수사권 조정 등이 이루어지면서 자치경찰제의 도입에 관한 논의가 본격적으로 진행되었다. 결국 2020년 12월 31일부로 「경찰법」이 폐지되고, 「국가경찰과 자치경찰의 조직 및 운영에 관한 법률」로 전부 개정되어 2021년 1월 1일부터 시행되고 있다. 그러나 자치경찰제에 대해서는 여전히 비판과 우려의 목소리가 많은 것이 사실이다. 특히 광역단체장, 국회, 지역 정치인 등 지역토착세력에 대한 정치적 중립성 확보방안에 대한 문제가 가장 많이 거론되고 있으며, 초기 단계에서 발생할 수 있는 시민에 대한 여러 유형의 인권침해 문제, 그리고 국가경찰과 자치경찰의 사무분배나 사건의 책임소재에 대한 문제와 자치경찰제 운영을 위한 재정부담의 문제 등이 제기되고 있다. 본 연구에서는 선행 연구에서 언급한 여러 대안들을 살펴보면서 국민에게 신뢰받을 수 있는 자치경찰제도의 정착이 이루어질 수 있는 해결책들을 모색해 보았다. 앞으로 운영될 자치경찰제도와 관련하여 새로운 제도 도입으로 발생할 수 있는 혼란을 최소화 하고자 노력해야 할 것이며, 지역주민들과 함께 소통하면서 서로 이해하는 과정을 끊임없이 가져야 할 것이다.

In this study, the effect of surfactants and liquid temperature on boiling regime transitions of high-temperature rod during quenching was examined using inverse heat transfer analysis. Liquid pools of the aqueous sodium dodecyl sulfate (SDS) and Triton X-100 solutions were used with pure water. In the present experimental range, the critical heat flux (CHF) and minimum film boiling (MFB) point for all test fluids increased as the liquid temperature decreased. On the other hand, the SDS and Triton X-100 surfactants suppressed the CHF and MFB point, which might be due to the enhancement of vapor film stability caused by reduced surface tension. Some previous experimental studies have reported that the surfactants enhance the boiling regime transitions, but their results seem to be contradictory to the present ones. Considering the present study with the previous works, the surfactants seem to have different effect on boiling phenomena depending on the boiling regime. In other words, in the aqueous surfactant solution, the boiling regime transition points seem to be markedly influenced by a path of boiling regime. In addition, boiling mode diagrams were presented for pure water and aqueous surfactant solutions.

Thinning silicon wafers for stacking in limited space is essential for the 3-D integration (3DI) technology of semiconductors. Due to the lack of research on the mechanical properties of thinned silicon wafers, it is difficult to assess and improve the mechanical reliability of 3DI semiconductor devices. This article reports the effects of thickness and crystallographic orientation on the tensile properties, such as Young’s modulus, elongation, and strength, of the thinned silicon wafer. Tensile properties of a {100} silicon wafer are measured using a direct tensile testing system, where a digital image correlation method is adopted for accurate strain measurement. Femtosecond laser patterning for accurate shape control is used to fabricate dog-bone-shaped specimens with various thicknesses and crystallographic orientations. The effect of crystallographic orientation is investigated for $\langle 110\rangle $ , $\langle 320\rangle $ , $\langle 210\rangle $ , and $\langle 100\rangle $ orientations. The Young’s modulus of each orientation closely matches the theory of anisotropic elasticity. The surface energy ratios between crystallographic planes are calculated using fracture mechanics analysis. As the thickness decreases from 100 to $10~\mu \text{m}$ , the elongation and strength increase threefold, while Young’s modulus is constant along the $\langle 110\rangle $ direction. The strength results are analyzed with a Weibull statistical size effect model, where the Weibull modulus is calculated to be 2.35, which correlates strength only with thickness variation. Using this value and the Weibull size effect model, the expected strength of specific thickness can be calculated easily without additional experiments.

The aim of this systematic review and network meta-analysis is to evaluate the comparative effectiveness of N95, surgical/medical and non-medical facemasks as personal protective equipment against respiratory virus infection. The study incorporated 35 published and unpublished randomized controlled trials and observational studies investigating specific mask effectiveness against influenza virus, SARS-CoV, MERS-CoV and SARS-CoV-2. We searched PubMed, Google Scholar and medRxiv databases for studies published up to 5 February 2021 (PROSPERO registration: CRD42020214729). The primary outcome of interest was the rate of respiratory viral infection. The quality of evidence was estimated using the GRADE approach. High compliance to mask-wearing conferred a significantly better protection (odds ratio [OR], 0.43; 95% confidence interval [CI], 0.23-0.82) than low compliance. N95 or equivalent masks were the most effective in providing protection against coronavirus infections (OR, 0.30; CI, 0.20-0.44) consistently across subgroup analyses of causative viruses and clinical settings. Evidence supporting the use of medical or surgical masks against influenza or coronavirus infections (SARS, MERS and COVID-19) was weak. Our study confirmed that the use of facemasks provides protection against respiratory viral infections in general; however, the effectiveness may vary according to the type of facemask used. Our findings encourage the use of N95 respirators or their equivalents (e.g., P2) for best personal protection in healthcare settings until more evidence on surgical and medical masks is accrued. This study highlights a substantial lack of evidence on the comparative effectiveness of mask types in community settings.

We performed an umbrella review on environmental risk/protective factors and biomarkers for postpartum depressive symptoms to establish a hierarchy of evidence. We systematically searched PubMed, Embase, and the Cochrane Database of Systematic Reviews from inception until 12 January 2021. We included systematic reviews providing meta-analyses related to our research objectives. Methodological quality was assessed by AMSTAR 2, and the certainty of evidence was evaluated by GRADE. This review was registered in PROSPERO (CRD42021230784). We identified 30 articles, which included 45 environmental risk/protective factors (154594 cases, 7302273 population) and 9 biomarkers (2018 cases, 16757 population). The credibility of evidence was convincing (class I) for antenatal anxiety (OR 2.49, 1.91-3.25) and psychological violence (OR 1.93, 1.54-2.42); and highly suggestive (class II) for intimate partner violence experience (OR 2.86, 2.12-3.87), intimate partner violence during pregnancy (RR 2.81, 2.11-3.74), smoking during pregnancy (OR 2.39, 1.78-3.2), history of premenstrual syndrome (OR 2.2, 1.81-2.68), any type of violence experience (OR 2.04, 1.72-2.41), primiparity compared to multiparity (RR 1.76, 1.59-1.96), and unintended pregnancy (OR 1.53, 1.35-1.75).

The use of surfactant has been known as one of effective ways to improve the boiling heat transfer. However, the most of boiling research using the surfactant has focused on the nucleate boiling regime, and the surfactant effect on the MFB (minimum film boiling) point, identified with MFBT (minimum film boiling temperature) and MHF (minimum heat flux) has rarely been studied. In the present study, the effects of surfactant and liquid subcooling on MFB point of vertical stainless steel cylinder were investigated experimentally using the quenching method. As the test fluids, the aqueous SDS (sodium dodecyl sulfate) solutions (1000 wppm and 2000 wppm), known to enhance the nucleate boiling heat transfer, were tested with pure water, where their liquid subcoolings covered from 0 °C to 39 °C. Based on the present experimental data, it was revealed that the SDS surfactant can impede the MFB point, while the increase of liquid subcooling leads to accelerating the MFB point. In addition, the influence of contact angle on MFB point was examined and discussed in detail. It was found that it could be insufficient and limited to explain the general trends of MFB point using contact angle alone and the fundamental factors responsible for changing the contact angle and thermal-hydraulic conditions should be considered.

The use of human gesturing to interact with devices such as computers or smartphones has presented several problems. This form of interaction relies on gesture interaction technology such as Leap Motion from Leap Motion, Inc, which enables humans to use hand gestures to interact with a computer. The technology has excellent hand detection performance, and even allows simple games to be played using gestures. Another example is the contactless use of a smartphone to take a photograph by simply folding and opening the palm. Research on interaction with other devices via hand gestures is in progress. Similarly, studies on the creation of a hologram display from objects that actually exist are also underway. We propose a hand gesture recognition system that can control the Tabletop holographic display based on an actual object. The depth image obtained using the latest Time-of-Flight based depth camera Azure Kinect is used to obtain information about the hand and hand joints by using the deep-learning model CrossInfoNet. Using this information, we developed a real time system that defines and recognizes gestures indicating left, right, up, and down basic rotation, and zoom in, zoom out, and continuous rotation to the left and right.

Background: Numerous potential environmental risk/protective factors and biomarkers for attention deficit/hyperactivity disorder (ADHD) have been investigated, but their consistency and magnitude are unclear. Methods: We conducted an umbrella review (registered in PROSPERO, registration: CRD42019145032) to systematically appraise the evidence of association between risk/protective factors or biomarkers and ADHD. We searched PubMed/MEDLINE, Embase, and Cochrane Database of Systematic Reviews from inception to Oct 31 st , 2019 and screened the references of relevant articles. We calculated the summary effect estimates (e.g. odds ratio [OR], relative risk [RR], and weighted mean difference [WMD]), 95% confidence interval, heterogeneity I 2 statistic, 95% prediction interval, small study effects and excess significance biases. Analyses under credibility ceilings were conducted. We assessed the quality of the meta-analyses with AMSTAR 2. Findings: The 37 eligible articles yielded 67 meta-analyses encompassing 43 environmental risk/protective factors (ADHD cases= 728 899, population=37 898 120) and 24 biomarkers (cases=13 784, population=37 629). Evidence of association was convincing (class I) for maternal pre-pregnancy obesity (OR=1·63, 1·49-1·77), childhood eczema (OR=1·31, 1·20-1‧44), preeclampsia (OR=1·31, 1·23-1‧40), hypertensive disorders during pregnancy (OR=1·29, 1·22-1·36), and maternal acetaminophen exposure during pregnancy (RR=1·25, 95% CI=1·17-1·34), and highly suggestive (class II) for maternal smoking during pregnancy (OR=1·56, 1·41-1·73), childhood asthma (OR=1·51, 1·4-1·63), childhood unhealthy dietary pattern (OR=1·41, 1·25-1·58), maternal pre-pregnancy overweight (OR=1·28, 1·21-1·35), and low serum vitamin D (WMD=−6·93, −9·34-−4·51). Interpretation: Pre-pregnancy obesity, overweight, and acetaminophen in pregnancy are strongly associated with ADHD. However, these associations are not necessarily causative and further high-quality studies to confirm these findings would be required. Funding Statement: None. Declaration of Interests: The authors declare no competing interests in relation to the current manuscript. Ethics Approval Statement: PROSPERO: CRD42019145032

Dementia is defined as a severe form of cognitive impairment. Research concerning the two-way relationship between depression and cognitive impairment has been conducted, however, there has been little analysis of cognitive function following changes in depressive status. This study describes the association between changes in depressive state and cognitive function in a Korean geriatric population sample. Using the Korean Longitudinal Study of Aging (KLoSA) database, Mini-Mental State Examination (MMSE) scores and Center for Epidemiologic Studies Depression Scale (CESD-10) indexes were used for measuring cognitive function and depression, respectively. The survey population was divided into four case categories by change in depressive status: normal to normal (Group A), normal to depressive (Group B), depressive to normal (Group C), and depressive to depressive (Group D). Analysis of variance, multiple regression analysis, and subgroup analysis were used for statistical examination. In the multiple regression analysis between MMSE values and depressive status change groups, with Group A as the reference, &beta, in all other groups was negative, and its absolute value was large in the order of D, B, and C in both men (B: &minus, 0.717, C: &minus, 0.416, D: &minus, 1.539) and women (B: &minus, 0.629, C: &minus, 0.430, D: &minus, 1.143). There were also significant results in the subgroup analysis in terms of age, working status, participation in social activities, regular physical activities, and number of chronic medical conditions. In conclusion, both cases&mdash, those suffering from depression and those having suffered from it before&mdash, experience cognitive impairment. The degree of cognitive function being impaired is greater in the case of depression-onset than that of depression-remission. Age, stimulating activities, and chronic conditions are also strongly relevant to cognitive decline accompanied by changes in depressive state.

Although intermolecular charge transport is known to occur via π–π stacking, the influence of π–π stacking on the mechanical properties of polymers has received little attention compared with other dynamic noncovalent interactions. Herein, we demonstrate a method to enhance stretchability via lowering crystallinity and increasing π–π stacking of thiophene-based random copolymer chains, which causes π–π stacking-induced polymer networks to form within the fully conjugated semiconducting polymer matrix. The polymer networks contain coiled amorphous chains that aid energy dissipation when the polymer film is subjected to strain; furthermore, the π–π stacking prevents the chains from irreversible sliding out of place due to the applied strain and provides interchain charge transport. Consequently, we are able to improve the polymer’s mechanical properties such as elongation at break, tensile strength, and toughness along with charge mobility. Additionally, our polymer shows great tolerance to a 40% strain wit...

In this study, we demonstrate that the introduction of small amounts of phenyl-C71-butyric acid methyl ester (PC71BM) into all-polymer solar cells (all-PSCs) increases the photovoltaic performance without compromising mechanical properties. Ternary blend polymer solar cells (ternary-PSCs) consisting of a polymer donor (PTB7-Th) and an acceptor mixture with different weight ratios of a polymeric acceptor (P(NDI2HD-T2)) and PC71BM demonstrate the effects of PC71BM loading on the power conversion efficiency (PCE) and mechanical properties. A significant enhancement in the PCEs of ternary-PSCs, from 6.32% to 7.33%, is observed when PC71BM is added into the active layer as up to 30 wt% of the acceptor mixture. Importantly, the excellent mechanical properties (i.e., crack onset strain = 11.6%, toughness = 2237 J m−3) of the blend films are well preserved at PC71BM loadings at or below 30 wt%. In contrast, both the PCE and the mechanical performance of the ternary-PSCs significantly decrease at higher PC71BM loadings (>50 wt%). Detailed morphological analysis via grazing incidence X-ray scattering measurements reveals that PC71BM molecules are well-dispersed in the amorphous portion of the active layer at PC71BM loadings up to 30 wt%. Therefore, both the mechanical and photovoltaic performances of the ternary-PSCs correlate closely with their morphological behavior, particularly in terms of the mixing behavior of PC71BM with polymers. The well-dispersed PC71BM molecules in the amorphous polymer domains facilitate efficient exciton dissociation, whereas the formation of PC71BM aggregates above a critical concentration causes severe mechanical degradation of the ternary-PSCs due to the presence of weak interfaces between the brittle PC71BM and polymer domains. Therefore, the ternary blends with optimal content of polymer/fullerene acceptors represent important candidates for flexible and wearable solar cells that require both high mechanical and photovoltaic performances.

This study introduces and describes a demonstration island of low-voltage direct current (LVDC) distribution system. The LVDC distribution system is planned to be constructed in an island of South Korea named Geochado by a project of KEPCO (Korea Electric Power Corporation). In this study, the network design of the demonstration island is proposed. A new DC network will be installed to demonstrate the LVDC distribution system and is planned to operate with the existing AC network. In addition, this paper presents the composition of loads for the DC network demonstration and distribution energy resources (DER) containing renewable energy resources. A variable speed function is planned to be developed for fuel efficiency operation. To calculate optimal DER capacity, HOMER microgrid economic analysis tool is used. Optimal HOMER results are presented with several cases. The final DER capacity is selected by considering the cost, stability and recent weather conditions. The energy management system is designed for efficient monitoring and control of LVDC distribution system. In addition, heat management system, power management system and automatic demand response are applied for demonstration. Each system interface method and a communication method for systems and field devices are proposed. Finally, the operation strategy for the LVDC distribution system is proposed in this study.

This paper reports the tensile properties and fracture mechanism of PTB7:PC71BM bulk heterojunction (BHJ) films as a function of composition mixing ratio. An increased concentration of fullerene makes the BHJ films stiffer and more brittle, and fracture occurs along aggregated fullerene domain boundaries. The tensile strength is maximized at a polymer–fullerene content ratio of 1:1. Furthermore, an additive, 1,8-diiodoctane (DIO), in the films induces fine nanomorphology, which increases the stiffness and strength and reduces the ductility of the films further. This is especially true under a high PC71BM load due to the expanded interfacial surface areas between the PC71BM and PTB7 polymer domains. The photovoltaic performance of the BHJ films on polydimethylsiloxane (PDMS) substrates after tensile stretching cycles is also examined in detail.

The mechanical properties of organic electronic materials and interfaces play a central role in determining the manufacturability and reliability of flexible and stretchable organic electronic devices. The synergistic effects of mechanical stress and deformation, together with other operating parameters such as temperature and temperature cycling, and exposure to solar radiation, moisture, and other environmental species are particularly important for longer-term device stability. We review recent studies of basic mechanical properties such as adhesion and cohesion, stiffness, yield behavior, and ductility of organic semiconducting materials, and their connection to underlying molecular structure. We highlight thin-film metrologies to probe the mechanical behavior, including when subjected to simulated operational conditions. We also report on strategies for improving reliability through interface engineering and tailoring material chemistry and molecular structure. These studies provide insights into how these metrologies and metrics inform the development of materials and devices for improved reliability.

Coefficient of thermal expansion (CTE) for thin film has been measured only from change in thickness because thin film has to be constrained on a solid substrate. However, thin film CTE shows different values depending on the supporting solid substrate. Here, a novel measurement method is suggested to quantitatively measure the in-plane thermal expansion of thin films floating on a water surface. In-plane thermal expansion of thin films on water surface is achieved by heating the water. The CTE is measured through a digital image correlation (DIC) technique. The DIC tracks displacement marks deposited on the film surface, and the in-plane thermal strain is defined as the change in distance between the patterns. The method can be applied to measure the CTE of polymer, metal, and graphene with a thickness ranging from a micrometer to one-atom-thickness. The in-plane thermal expansion of the polystyrene (PS) thin film decreased as the film thickness decreased. The negative CTE of graphene is also successfully explored without any substrate effects or complicated calculations. The CTE measurement method can provide understanding of the intrinsic thermal expansion behavior of thin films including emerging two-dimensional materials.

Mechanical robustness of polymer solar cells should be ensured for the device reliability, but the brittle active layers of fullerene derivative based polymer solar cells would fracture easily causing the device failure. Therefore, mechanical properties of polymer solar cells should be investigated thoroughly in order to enhance the mechanical reliability. Herein, the mechanical properties of polymer solar cells were examined depending on the acceptor types (polymer or small molecule acceptors) and the content. In addition, the fracture behaviors were revealed in detail with various morphology analyses. This result demonstrates the importance of polymer acceptors to improve the mechanically robustness of polymer solar cells.

This study aimed to investigate the cross-sectional association between arthritis and migraine in a large representative sample of the US adult population. The study used data from adults who participated in the RAND American Life Panel (ALP). Arthritis (excluding rheumatoid arthritis) and migraine were self-reported. Control variables included sex, age, ethnicity, marital status, education, employment, annual family income, stroke, epilepsy, coronary artery disease, asthma, depression, anxiety, bipolar disorder, and alcohol dependence. The association between arthritis and migraine was investigated using multivariable logistic regression models, while sex and age interaction analyses were also conducted. This study included 2649 adults (51.7% women, mean (SD) age 50.6 (15.9 years). The prevalence of migraine was 10.7% in the sample. After adjusting for several potential confounders, there was a significant association between arthritis and migraine (OR = 1.83, 95% CI = 1.20&ndash, 2.81). Further sensitivity analyses revealed that the association was significant in women, adults aged &le, 45 years, and those aged &gt, 65 years. The mere fact that arthritis and migraine may coexist is problematic, as this could lead to an important medical and economic burden. Therefore, strategies should be implemented to reduce the cooccurrence of these two chronic conditions.

Graphene produced by chemical-vapor-deposition inevitably has defects such as grain boundaries, pinholes, wrinkles, and cracks, which are the most significant obstacles for the realization of superior properties of pristine graphene. Despite efforts to reduce these defects during synthesis, significant damages are further induced during integration and operation of flexible and stretchable applications. Therefore, defect healing is required in order to recover the ideal properties of graphene. Here, the electrical and mechanical properties of graphene are healed on the basis of selective electrochemical deposition on graphene defects. By exploiting the high current density on the defects during the electrodeposition, metal ions such as silver and gold can be selectively reduced. The process is universally applicable to conductive and insulating substrates because graphene can serve as a conducting channel of electrons. The physically filled metal on the defects improves the electrical conductivity and mechanical stretchability by means of reducing contact resistance and crack density. The healing of graphene defects is enabled by the solution-based room temperature electrodeposition process, which broadens the use of graphene as an engineering material.

We have designed and successfully implemented 360-degree viewable holographic display prototype systems. Core idea of the system design lies in the exploitation of fast operating speed of DMD for binary amplitude modulation of light field, being distributed to more than 1,000 viewpoints along the 360 degree viewing circumference. Slanted downward viewing angle and 360 degree viewable 3-dimensional(3D) image over the center of tabletop display is achieved by specially designed optics. As a result, solid-looking 3D moving color images of larger than 3 inches are rendered and observed by several viewers at the same time from different viewing positions. We have implemented and experimented several variations of the system. They are tiling of SLM modules(2x2 tiling with 4 DMDs for mono-color display and 1x2 tiling with 6 DMDs for color display), using different SLMs(DMD of pixel pitch 13.68μm and resolution 1,024x768, DMD of pixel pitch 10.8μm and resolution 1,920x1,200), and applying different structure of image floating optics((1)double parabolic mirrors, (2)one parabolic mirror and one beam splitter, (3)two spherical and one flat mirror). We report the result of various display system implementations based on several combinations of above-mentioned design options.

In this study, effects of size and direction on mechanical properties of thinned single crystal silicon wafer are investigated by the direct tensile test. The silicon wafer is {001} and femtosecond laser patterning is used for fabricating dog-bone specimens for uniform stress distribution in gauge length. Mechanical properties of specimens with a thickness of 10, 20, 50, and 100-μm and with a direction of , , , and are measured to identify effects of size and direction, respectively. Young's modulus of thinned single crystal silicon wafer was constant while strength increased, as the thickness decreased. When the direction changed, each direction of the thinned silicon wafer has its inherent Young's modulus, and the experimental data fitted well with the theory of anisotropic elasticity.

Holographic displays are ideal imaging technologies because they allow objects to be reconstructed three-dimensionally to any desired distance without an accommodation convergence conflict. Therefore, unlike traditional two-dimensional displays, measurement of the image quality of a holographic display is based on an image reconstructed in three-dimensional space. In this paper, we propose a 3D MTF measurement method as a quantitative evaluation method for the image quality of holographic displays. We show the experimental result of our tabletop holographic display by exploiting the proposed method.

Metal thin film electrodes on flexible polymer substrates are inherently unstable against humidity and mechanical stresses because of their poor adhesion properties. We introduce a novel approach for improving the adhesion characteristics of metal-polymer interface based on the nanostructuring of the polymer substrate by using nanoimprint lithography. The adhesion characteristics of metal-polymer interface were measured by accelerated test, cyclic bending test and double cantilever beam (DCB) test. The interface of Au/Ti dual layer thin film and nanoimprinted PMMA substrate shows over 2.03 and 1.95 times higher adhesion energy (G(c)) than that of Au/Ti dual layer thin film and plane PMMA substrate in air and wet environments, respectively. The adhesion energy between metal thin film and polymer substrate was dramatically improved by the increased surface roughness and mechanical interlocking effect of numerous nanoscale anchors at the edges of nanoimprinted surface, which was verified by both experiment and numerical analysis.

The time and spatial multiplexing which are frequently employed in holographic displays based on display chips of the same characteristics, to increase reconstructed image size and resolution can hardly improve the viewing condition such as viewing zone and viewing angles more than what a chip can offer. This is demonstrated optically and experimentally with the holographic displays built with an array of 2×10 DMDs which is formed both by time and spatial multiplexing. It is considered that the viewing condition of the spatial multiplexing is somewhat worse than that obtained by time multiplexing because the reconstructed image size of each chip cannot be smaller than the hologram size. Furthermore, the spatially multiplexed image can be noisier than that obtained from time multiplexing but it shows better light efficiency. Added on this, it does not introduce a distortion in the image as in the time multiplexing.

A new system for evaluating the voltage management errors of distribution equipment is presented in this paper. The main concept of the new system is to use real distribution live-line voltage to evaluate and correct the voltage measurement data from distribution equipment. This new approach is suitable for a new Distribution Management System (DMS) which has been developed for a distribution power system due to the connection of distributed generation growth. The data from distribution equipment that is installed at distribution lines must be accurate for the performance of the DMS. The proposed system is expected to provide a solution for voltage measurement accuracy assessment for the reliable and efficient operation of the DMS. An experimental study on actual distribution equipment verifies that this voltage measurement accuracy assessment system can assess and calibrate the voltage measurement data from distribution equipment installed at the distribution line.

Considering all the potential applications of organic electronics in portable, wearable, and implantable devices, it is of great importance to develop electroactive materials that possess mechanical reliability along with excellent electronic performance. The coexistence of these two attributes, however, is very difficult to achieve because there is an inverse relationship between the electrical properties and the mechanical flexibility, both of which are associated with the conjugation length and intermolecular ordering of the polymers. Herein, we demonstrate a simple and robust approach based on solution assembly of two different poly(3-hexylthiophene)s (P3HTs) with regioregularity (RR) contents of 97% and 66% to impart both electrical and mechanical properties to films for organic electronic applications. The 97% RR P3HT exhibits high electronic performance but poor mechanical resilience, and vice versa for the 66% RR P3HT. Selective crystallization of high RR P3HT induced by solution assembly allows the use of a one-step process to construct percolated networks of high RR P3HT nanowires (NWs) in a low RR P3HT matrix. Only 5 wt % of high RR P3HT NWs in a 95 wt % low RR P3HT matrix was required to produce hole mobilities comparable to that of pure high RR P3HT, and this blend film exhibited improvements by factors of 20 and 60 in elongation at break and toughness, respectively. Selective self-assembly of RR-controlled polymers allowed us to overcome the fragile nature of highly crystalline conjugated polymer films without sacrificing their electronic properties.

This paper describes a comparison of two characterization techniques for determining the mechanical properties of thin-film organic semiconductors for applications in soft electronics. In the first method, the film is supported by water (film-on-water, FOW), and a stress–strain curve is obtained using a direct tensile test. In the second method, the film is supported by an elastomer (film-on-elastomer, FOE), and is subjected to three tests to reconstruct the key features of the stress–strain curve: the buckling test (tensile modulus), the onset of buckling (yield point), and the crack-onset strain (strain at fracture). The specimens used for the comparison are four poly(3-hexylthiophene) (P3HT) samples of increasing molecular weight (Mn = 15, 40, 63, and 80 kDa). The methods produced qualitatively similar results for mechanical properties including the tensile modulus, the yield point, and the strain at fracture. The agreement was not quantitative because of differences in mode of loading (tension vs comp...

Additional file 1: Figure S1. Expanded mass spectra of reaction products obtained from the incubation of cellulose with TtAA9E or TaAA9A using MALDI-TOF/TOF MS. Avicel (5%, w/v) was incubated with TtAA9E or TaAA9A (1 mg/g Avicel) in 50 mM sodium acetate (pH 5.0) with 10 mM of ascorbic acid at 50 °C for 4 days. Expanded mass spectra for a DP5, b DP6, and c DP7 products obtained from the incubation of cellulose with TtAA9E or TaAA9A. 100% relative intensity represents 4.62 × 104 a.u. for DP5 and DP6 and 3.00 × 104 a.u. for DP7. Possible products by C1 oxidation are aldonic acid, sodium adduct of aldonic acid, and 1,5 δ-lactone, and those by C4 oxidation are 4-ketoaldose and gemdiol. Product that contain both aldonic acid and gemdiol, 1,5 δ-lactone and gemdiol, or aldonic acid and 4-ketoaldose is an evidence of double (C1/C4) oxidation. The detailed mass information is shown in the text and Fig. 2.

While most high-efficiency polymer solar cells (PSCs) are made of bulk heterojunction (BHJ) blends of conjugated polymers and fullerene derivatives, they have a significant morphological instability issue against mechanical and thermal stress. Herein, we developed an architecturally engineered compatibilizer, poly(3-hexylthiophene)-graft-poly(2-vinylpyridine) (P3HT-g-P2VP), that effectively modifies the sharp interface of a BHJ layer composed of a P3HT donor and various fullerene acceptors, resulting in a dramatic enhancement of mechanical and thermal stabilities. We directly measured the mechanical properties of active layer thin films without a supporting substrate by floating a thin film on water, and the enhancement of mechanical stability without loss of the electronic functions of PSCs was successfully demonstrated. Supramolecular interactions between the P2VP of the P3HT-g-P2VP polymers and the fullerenes generated their universal use as compatibilizers regardless of the type of fullerene acceptors, including mono- and bis-adduct fullerenes, while maintaining their high device efficiency. Most importantly, the P3HT-g-P2VP copolymer had better compatibilizing efficiency than linear type P3HT-b-P2VP with much enhanced mechanical and thermal stabilities. The graft architecture promotes preferential segregation at the interface, resulting in broader interfacial width and lower interfacial tension as supported by molecular dynamics simulations.

This paper compares the differences in economic feasibility and dynamic characteristics between underground (U/G) cable and overhead (O/H) line for low-voltage direct current (LVDC) distribution. Numerous low loaded long-distance distribution networks served by medium-voltage alternative current (MVAC) distribution lines exist in the Korean distribution network. This is an unavoidable choice to compensate voltage drop, therefore, excessive cost is expended for the amount of electrical power load. The Korean Electric Power Corporation (KEPCO) is consequently seeking a solution to replace the MVAC distribution line with a LVDC distribution line, reducing costs and providing better quality direct current (DC) electricity. A LVDC distribution network can be installed with U/G cables or O/H lines. In this paper, a realistic MVAC distribution network in a mountainous area was selected as the target model to replace with LVDC. A 30 year net present value (NPV) analysis of the economic feasibility was conducted to compare the cost of the two types of distribution line. A simulation study compared the results of the DC line fault with the power system computer aided design/electro-magnetic transient direct current (PSCAD/EMTDC). The economic feasibility evaluation and simulation study results will be used to select the applicable type of LVDC distribution network.

With power systems switching to smart grids, real-time and on-line monitoring technologies for underground distribution power cables have become a priority. Most distribution components have been developed with self-diagnostic sensors to realize self-healing, one of the smart grid functions in a distribution network. Nonetheless, implementing a real-time and on-line monitoring system for underground distribution cables has been difficult because of high cost and low sensitivity. Nowadays, optical fiber composite power cables (OFCPCs) are being considered for communication and power delivery to cope with the increasing communication load in a distribution network. Therefore, the application of distributed temperature sensing (DTS) technology on OFCPCs used as underground distribution lines is studied for the real-time and on-line monitoring of the underground distribution power cables. Faults can be reduced and operating ampacity of the underground distribution system can be increased. This paper presents the development and improvement of an intelligent cable monitoring system for the underground distribution power system, using DTS technology and OFCPCs as the underground distribution lines in the field.