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Nasogastric intubation is a common procedure in hospitals that causes adverse outcomes if performed incorrectly. There is currently insufficient guidance for patient positioning, which increases the success of nasogastric intubation at the bedside. Therefore, a systematic review with a meta-analysis was performed to determine the effectiveness of changing an unconscious adults' positions compared with the supine position to improve the correct placement of a nasogastric tube, intubation time, and complications. The Cochrane Library, MEDLINE, Embase, PubMed, and CINAHL databases were searched from inception to April 2019 for randomized controlled trials. The Cochrane Collaboration Risk of Bias tool was used to assess the quality of eligible studies. Cochrane Review Manager 5.3 software was used to analyze the data. A total of 288 articles were obtained in the literature search, 10 of which were included in the analysis. Most of the included trials were at low risk of bias. All postures were significantly effective, though neck flexion had the highest success rate (odds ratio = 4.87, 95% confidence interval [2.48, 9.57], Z = 4.6, p.00001, I2 = 0%) for nasogastric intubation. In terms of the time required for the procedure, compared with the usual posture, although the total effects were significant ( MD =-10.33, 95% confidence interval [-15.38, -5.29], Z = 4.02, p.00001, I2 = 98%), only neck flexion and lifting of the larynx reduced the time. The meta-analysis suggests that patient positioning improves the success rate of nasogastric intubation and increases safety. Finally, the authors developed a procedural instruction sheet to aid practitioners with nasogastric intubation.

Unlike Korean or Vietnamese adoptees who came to the U.S. during the postwar era, Chinese adoptees are mostly abandoned female infants under China’s one-child policy from 1980 through 2015. Little work has documented Chinese adoptees’ identity (trans)formation across time and space. This study examines how three Chinese adoptees from the U.S. who chose to go to Taiwan to teach English make sense of their Chinese heritages and their lives in and out of Asia. Drawing on the frameworks of positioning and chronotopic identities, this cross-sectional, multiple case study documents the participants’ identity (trans)formations through their narratives on their moves across the U.S., China, and Taiwan during different points of their lives. Our adoptee participants’ home and work experiences over time represent diverse pathways for their negotiations of various aspects of their identities – linguistic, cultural, Chinese, American, Asian American, and adoptee – in their life trajectories transnationally. Their diverse experiences complicate current understandings of adoptee identities within and across the adoptive home, the “homeland” of their birth places, and beyond.

BACKGROUND Nasogastric tube (NG) insertion is one of the essential clinical skills. Unfortunately, it’s a blind procedure, as one cannot directly visualize the tip of the NG during the insertion process. Thus, the most significant risk was malposition. Suppose blind insertion can be broken through in teaching strategies so that learners can see through the internal structure of the human body when performing technology. In that case, students can have better memory and comprehension and simultaneously provide real-time feedback, both of which are conducive to conceptualizing invasive surgical execution. OBJECTIVE A mobile-based interactive simulation scheme (MISS) was proposed, and a MISS-based learning system was developed to investigate its effects on facilitating hands-on learning of nasogastric tube (NG) insertion in Taiwanese undergraduate medical students. METHODS A randomized controlled trial (RCT) design was adopted for this research, for which 73 grade-five medical students were recruited. An interactive simulation scheme with a hands-on learning design in a MISS model was built on a web-based application running on mobile devices equipped with the touchscreen. Learning performance including the conceptual knowledge, self-confidence scales, and practical skills (an OSCE-based test) were evaluated to investigate the differences between experimental and control groups. The MISS-based learning system was also evaluated in terms of learning satisfaction, system usability, and task load. The statistical methods used in this work included t-test, ANCOVA, and the Johnson-Neyman analysis. RESULTS he results showed significant differences between the experimental and control groups in terms of both knowledge and self-confidence (P < .001). The levels of image, perceived enjoyment, perceived usefulness, and intention to use scales in the technology acceptance model (TAM) were higher in the high progress group than in the low progress group. Besides, the score of the OSCE test in the experimental group were higher than those in the control group, which had significant difference (t=3.079, P=.003). CONCLUSIONS The proposed MISS-based learning system can efficiently assist students in hands-on learning of nasogastric tube insertion. Accordingly, the learning outcomes and self-confidence can be significantly improved. Moreover, experimental results also show that the useful diagnostic and enjoyment features in the system enhance learners' intention toward use.

Face recognition plays an essential role for the biometric authentication. Conventional lens-based imagery keeps the spatial fidelity with respect to the object, thus, leading to the privacy concerns. Based on the point spread function engineering, we employed a coded mask as the encryption scheme, which allows a readily noninterpretable representation on the sensor. A deep neural network computation was used to extract the features and further conduct the identification. The advantage of this data-driven approach lies in that it is neither necessary to correct the lens aberration nor revealing any facial conformity amid the image formation chain. To validate the proposed framework, we generated a dataset with practical photographing and data augmentation by a set of experimental parameters. The system has the capability to adapt a wide depth of field (DoF) (60-cm hyperfocal distance) and pose variation (0 to 45 deg). The 100% recognition accuracy on real-time measurement was achieved without the necessity of any physics priors, such as the encryption scheme.

Translanguaging theory re-conceptualizes the linguistic systems and practices of multilinguals as well as multilingual classroom pedagogies. While many studies have documented translanguaging in bi...

In a broader context where English is marketed as a desirable product of consumption, hiring English speakers as language teachers and de facto cultural ambassadors is a common practice in some Eas...

Intercity railway system operation on national holidays can be challenging because of possible surging demand. This study proposes an analysis framework to investigate railway system ridership data on national holidays, seeking to attain better understanding of relevant intercity trip patterns, so as to enable enhanced preparation and response before and during national holidays. The ridership data are analyzed in the form of Origin–Destination (O-D) tables and regarded as pictures of N × N pixels, where N is the number of the considered stations/cities in a railway system. The framework primarily adopts a deep auto-encoder to process these pictures to reduce data dimensions and abstracting key features within these pictorial data. Based on the abstracted features, k-means clustering is then conducted to categorize the O-D tables with similar trip patterns into the same group. Further, a discrete outcome model based on logistic regression is developed on the clustering results to enhance the interpretation of the trip pattern in each group and identify the significant holiday-related characteristics and external factors that can affect the trip pattern generation. The ridership data of Taiwan Railways Administration associated with 38 national holidays from January 2014 to August 2018 are analyzed. The analysis results highlight insightful interpretation in relation to clustered trip patterns and relevant trip characterization relative to various national holidays. The proposed framework and developed discrete outcome model are also validated, showing 85% correct assignments of O-D tables to the groups of relevant trip patterns.

Increasingly, immigrant families in North America are sending their newborns to the parents’ country of origin to be raised by relatives until the children reach school age. Then they are returned ...

In this paper, we proposed a new technique to realize a high-quality three-dimensional (3D) display by using binary holograms. First, we applied a localized random down-sampling (LRDS) mask to down-sample the object function and generated a binary CGH by direct sign-thresholding. Subsequently, we devised the display by adaptive intensity accumulation (AIA). In AIA, multiple CGHs of the same object are generated. However, selective sampling points of the same scene are removed according to the reconstructed image of previous binary CGHs as the second and more binary CGHs are generated. Finally, these holograms are sequentially displayed on a fast spatial light modulator, a digital micromirror device (DMD). Thus, a high-quality 3D image is reconstructed without artifacts and speckle noise.

This study examines Asian students’ interracial/interethnic friendships at a multiracial middle school. Friendship groups remain predominantly segregated despite the school’s efforts, reflecting community and parental influences. The circulation of uncontested stereotypes such as “loud” and “brash” African Americans is based on normative ideas of communicative styles, making some Asian students hesitant to be friends with their African American peers. There also exists an Asian hierarchy where Chinese students look down upon Cambodian students who befriend African American students. This study demonstrates Asian students’ construction of their social networks is inseparable from the construction of Whiteness in the broader society.

Restaurant atmosphere can produce hedonic and practical shopping value and induce consumption loyalty. The aim of this study is to construct a consumer behavior model regarding the restaurant atmosphere, experiential value, restaurant image, and consumption loyalty by using a Sport-themed Restaurant. Regarding the materials and methods, the sample frame is a Sport-themed Restaurant in kaohsiung, Taiwan. Data were from employee convenience sampling with personal interview to collect data. The research targets obtain around 400 useful questionnaires. Regression analysis is to be used to test hypothesis. The results show that (1) Sport-themed restaurant atmosphere positively impacts experiential value, (2) experiential value positively impacts restaurant image, (3) restaurant image positively impacts consumption loyalty, and (4) restaurant atmosphere positively impacts consumption loyalty. The conclusion of this study includes that hypotheses 1, 2 and 3 are supported and this study also makes suggestion for the practitioners to plan and manage Sport-themed Restaurant in Taiwan.

One neurotoxic mechanism of amyloid-beta peptide (Aβ), the major component of senile plaques in the brains of Alzheimer's disease (AD) patients, is to trigger cell cycle reentry in fully differentiated neurons. However, the detailed underlying mechanisms remain unclear. Using Aβ25-35–treated primary rat cortical neurons as the experimental system, in the present study we tested whether Aβ-induced inhibitor of differentiation-1 (Id1)/hypoxia-inducible factor-1alpha (HIF-1α) and cyclin-dependent kinase-5 (CDK5) contribute to cell cycle reentry in fully differentiated post-mitotic neurons. We found that Id1-induced HIF-1α mediated Aβ25-35–dependent expression of the cell cycle markers cyclin D1 and proliferating cell nuclear antigen (PCNA), both colocalized with microtubule-associated protein-2 (MAP-2) + cells, indicative of cell cycle reentry in the mature neurons. Aβ25-35 also enhanced p35 cleavage to p25 without affecting CDK5 expression. The CDK5 inhibitor roscovitine and the siRNA targeting CDK5 both suppressed Aβ25-35–dependent HIF-1α expression and cell cycle reentry. Intriguingly, Aβ25-35–induced Id1 repressed p25 production while CDK5/p25 reciprocally inhibited Id1 expression, despite the observation that both Id1 and CDK5/p25 acted upstream of HIF-1α. These results demonstrated that both Id1/HIF-1 and CDK5/HIF-1 contribute to Aβ-induced cell cycle reentry in post-mitotic neurons; furthermore, Id1 and CDK5/p25 reciprocally suppress expression of each other.

This article takes a language ecology perspective on the interdependence of multiple Chinese languages in the heritage communities and classrooms of middle-school students. We describe how these students struggle with Mandarin as an imposed identity and consider productive classroom exercises of linguistic rescaling that help them to critically examine the diversity of Chinese languages. This study addresses the dearth of critical examination of non-Mandarin Chinese heritage students’ lived experiences by showing interactions in which they actively engage in disrupting and dismantling conventional notions of “Chinese”.

The demand for rail transportation in North America is expected to increase significantly in the coming decades. Additional capacity will be required to accommodate the new traffic demand for both passenger and freight services. The majority of the network is single track with passing sidings, which trains use for meets and passes; therefore, allocating sidings properly can significantly increase line capacity and reduce train delay. Railroads usually rely on experienced personnel to determine new siding locations to improve line capacity through infrastructure upgrades. Experienced railroaders often identify good solutions; however, this method does not guarantee that all good alternatives have been evaluated or that the best one is implemented. In this research, an optimal siding location model is developed with consideration of infrastructure and traffic characteristics to determine the optimal number and locations of sidings. The empirical results demonstrate that this model is able to generate an optimal plan for the number of additional sidings and their respective locations. This tool can therefore help railroads maximize their return on investment from capacity expansion projects and achieve the service quality desired by customers.

This paper investigates Mandarin learning experiences of Chinese American teenagers from working-class families. Drawing on a subset of data from a larger ethnographic study, we focus on 14 middle schoolers who studied Mandarin as a heritage language at a socially engaging school with Mandarin as part of its official curriculum. The data highlight a mismatch between students’ true heritage language and the institutionalized surrogate heritage language, which created unwanted implications for students’ investment and identities in the presence of Mandarin hegemony. In a time when the teaching of Mandarin receives unprecedented educational support, this study calls for more educational efforts that attend to the large population of heritage language learners from non-Mandarin language backgrounds. We suggest that Mandarin educators have critical language awareness so they can address Chinese American students’ multilingual backgrounds in ways that can value their home languages and support their investment ...

This study seeks to investigate issues transpiring in green hotels from a human resource perspective which is unlike most green-hotel studies centering on consumer behavioral subjects. It hypothesizes that the employees’ green ability consisting of environmental awareness, environmental knowledge, and environmental skill creates a positive impact on hotels’ green ability and ultimately on the overall performance of hotels. Using alumni from a tourism and hospitality program, this study collects 233 responses from a structured questionnaire survey. The findings indicate that hotel employees approximately contribute toward a fifth of the hotels’ ability to implement greener practices.

North American heavy haul railroads are experiencing growth in traffic demand and increases in capacity constraints. An appropriate service-design process is thus crucial to allow for more effective network capacity planning and efficient rail operations. Existing approaches to freight train routing usually ignore the congestion-induced delay and fail to consider the dynamics in link and node delay in response to traffic volume. Furthermore, different train types can have substantially different operating characteristics, including maximum speed, power-to-ton ratio, and dispatching priority. This heterogeneity causes conflicts between trains that can increase delays and reduce capacity. Therefore, traffic volume and heterogeneity should both be incorporated into the decision process for service design. In this research, the authors proposed to add an additional traffic routing process in service design and developed a novel optimization framework to route trains by considering link and node delay,...

Researchers have argued that macro-approaches to heritage language (HL) teaching that take into account heritage language learners' (HLLs) global knowledge of the HL are particularly effective; such macro-approaches are often characterized as discourse-based, content-based, genre-based, task-based, or experiential (Kagan and Dillon 2001, 2008, 2009). This paper describes a set of Mandarin HL curriculum and instructional methods that utilized the notion of macro-approaches to teach secondary students in a STARTALK summer program in 2009. The curriculum built on learners' prior strengths in speaking and listening to improve their writing and reading abilities and validated their hybrid identities as Chinese Americans. Class topics included the Chinese Exclusion Act and Chinese immigration, history and personal memories of Chinatown, intergenerational relationships, personal border-crossing experiences, and pop music in Mandarin-speaking regions. A class blog was used to further enhance HLLs' motiva...

This paper investigates the ways languages are used in Philadelphia Chinatown through qualitative content analysis of 330 photos. Examining the linguistic landscape of public spaces exposes issues of linguistic tensions, language vitality, and language shift in multilingual settings. While Chinese in the form of Mandarin is highly publicized, thereby placing disproportionate emphasis upon one language over others, Philadelphia Chinatown shows diversity, coexistence, and creative uses of multiple Chinese languages alongside English. The signage suggests linguistic rescaling connecting real and imagined audiences, conforming to broader ‘Chinese’ linguistic norms while localized to connect to a range of Chineses. We show how linguistic and cultural pluralism of ‘Chinese’ have always existed – and continue to exist – and the importance of developing socially sensitive literacy pedagogy, especially when there is a mismatch between the informal, community-level signage and what is formally taught in ‘Chinese’ language classrooms in the U.S. Keywords: linguistic landscape; Chinatown; Chinese languages; literacy education; heritage language; education

This overview and analysis of language policy and planning (LPP) in Taiwan since the seventeenth century is written from the perspective of language ecology and uses Cooper’s three-part approach: status planning, acquisition planning and corpus planning. The paper investigates how languages and their speakers have interacted with one another and with their sociocultural and political contexts, and how different policies at different times have altered the local language ecology. Three emerging factors that are changing the local ecology are further identified. As the first step to successful LPP is a detailed understanding of the local language ecology, it is hoped that the analysis presented here will provide insights for future LPP in Taiwan.

High-efficiency pure-white organic light-emitting diodes (OLEDs) were fabricated using small polysilicic acid nanodot embedded polymeric hole-transporting layer. By incorporating the nanodot, the efficiency of a solution-processed phosphorescent white OLED was increased from 6.8 to 23.7 Im/W, an improvement of 250%. 17.1 Im/W was obtained while the same concept was applied on a mixed-host composed fluorescent white OLED.

A relatively high-efficiency, fluorescent pure-white organic light-emitting diode was fabricated using a polysilicic acid (PSA) nanodot-embedded polymeric hole-transporting layer (HTL). The diode employed a mixed host in the single emissive layer, which comprised 0.5 wt % yellow 5,6,11,12-tetra-phenylnaphthacene doped in the mixed host of 50 % 2-(N,N-diphenyl-amino)-6-[4-(N,N-diphenylamino)styryl]naphthalene and 50 % N,N'-bis-(1-naphthyl)-N,N'-diphenyl-1,10-biphenyl-4-4'-diamine. By incorporating 7 wt % 3 nm PSA nanodot into the HTL of poly(3,4-ethylene-dioxythiophene)-poly-(styrenesulfonate), the efficiency at 100 cd m -2 was increased from 13.5lm W -1 (14.7 cd A -1 ; EQE: 7.2 %) to 17.1lm W -1 (17.6 cd A -1 ; EQE: 8.3 %). The marked efficiency improvement may be attributed to the introduction of the PSA nanodot, leading to a better carrier-injection-balance.

Efficient fluorescent white organic light-emitting diodes with low carrier-injection barriers were fabricated with device structure of indium tin oxide/N,N′-bis-(1-naphthy)-N,N′-diphenyl-1,1′-biphenyl-4-4′-diamine/white emission layer/1,3,5-tris(N-phenyl-benzimidazol-2-yl)benzene/lithium fluoride/aluminium. By blending in the blue host of 1-butyl-9,10-naphthalene-anthracene in the emissive layer an efficient electro-luminescent greenish-blue co-host of di(triphenyl-amine)-1,4-divinyl-naphthalene, with the doping of a trace amount of red dye of 4-(dicyano-methylene)-2-methyl-6-(julolidin-4-yl-vinyl)-4H-pyran, bright and colour-stable white emission with high power-efficiency of 14.6 lm/W at 100 cd/m2 or current efficiency of 19.2 cd/A at 300 cd/m2 or 18.7 cd/A at 10,000 cd/m2 was obtained. The resulted synergistic increase in brightness and efficiency may be attributed to the presence of cascading new routes with comparatively lower electron injection barrier.

The metabolites, (24S)-3β-acetoxyergost-5-en-21-oic acid (2), 5′-O-acetylthymidine (3), 3′-O-acetylthymidine (4), and p-vinylbenzyl alcohol (5), along with a known steroid (1) were isolated from the EtOAc extract of the Formosan soft coral Caldiella australis. The structures of new metabolites were determined on the basis of spectroscopic (including 1D and 2D NMR) analyses and by comparison of their NMR spectral data with those of related compounds. Except for 3, all compounds exhibited cytotoxic activity of various degrees of potency against a limited panel of human liver and breast cancer cell lines.

This critical ethnographic case study describes and interprets how an urban K-8 charter school in the United States with a large number of students of color from low-income communities offers education that recognizes students’ minority status in the broader society and envisions students as agents working toward a just society. The analyses show that the school’s progressive teaching of diversity has a positive impact on minority students’ identification with their heritages and their academic achievements. This study advances a critical understanding of creating equitable education at the school level.&nbsp

We report a novel solution-processable high molecule iridium complex, bis[5-methyl-7-trifluoro methyl-5H-enzo(c)(1,5)naphthyridin-6-one]iridium(picolinate) (CF3BNO), that exhibits a relatively short excited-state lifetime (0.30 μs) and extremely high quantum yield (95%). Current efficiency of 89.1 cd A−1 at 100 cd m−2 was obtained by using the CF3BNO complex to fabricate a blue-green light-emitting device.

With 3D stacking design, high-performance low-power complex design is practical. However, due to the high design costs and extensive design efforts, 3D technology is not broadly adopted. For 3D stacking designs, most chip failures are due to power supply problems of voltage drop and noisy voltage. A feasible low-cost 3D stacking design method is proposed. Multiple voltage design technique is applied to reduce power consumption. A low-power built-in digitalized power-aware management mechanism for multiple voltage domain design is adopted. A power switch control circuit is used to support multiple operation modes for multiple voltage designs. A built-in voltage meter is proposed for internal voltage level observation. A powerless retention flip flop is applied for temporary data storage. These efficient power-aware adjusting mechanisms are successfully validated by a low-power, noisy-voltage tolerant 64bit multiplier using a low-cost 3D stacking technique.

Our continuing effort of searching bioactive substances from the Formosan soft coral Cladiella australis has led to the isolation of a bioactive substance austrasulfone (1), which possesses significant neuroprotective activities. A straightforward synthesis of 1 was achieved by a two-step reaction sequence. Dihydroaustrasulfone alcohol (3), the synthetic precursor of 1, not only exhibited in vitro anti-inflammatory activity, but also showed potent therapeutic ability in the treatment of neuropathic pain, atherosclerosis, and multiple sclerosis in rats.

High-efficiency is strongly desired for organic light-emitting diodes (OLEDs) to be fully realized as the future display and lighting technology. To replace current illumination tools, such as incandescent bulbs and fluorescent tubes, for examples, OLEDs with much higher efficiency are demanded. We will present herein some approaches for fabricating high-efficiency OLEDs of blue and white emission. Besides employing highly efficient electroluminescent guests and thin device architecture, low injection barriers to carriers, high carrier-transporting character, effective carrier/exciton confinement, balanced carrier-injection, exciton generation on host, effective host-to-guest energy-transfer and improved light-coupling efficiency are essential. Amongst, the incorporation of nano-dots in emissive- and non-emissive-layers can markedly improve the device efficiency. The enhancement is especially marked as small polymeric nano-dots are incorporated into the non-emissive layers. Since the incorporation is not in the emissive layer, the efficiency improvement mechanism works for both fluorescent and phosphorescent devices. Importantly, the efficiency improvement is also a strong function of the surface charge density of the nano-dots. Regardless positively or negatively charged, the improvement becomes more pronounced as the charge density increases. Results regarding some lately achieved extraordinarily highly-efficient OLEDs containing nano-dots with high surface charge will be presented.

High-efficiency fluorescent white organic light-emitting diodes (OLED) were fabricated by using double hole-transporting-layers (HTLs), poly(3,4-ethylene- dioxythiophene)-poly-(styrenesulfonate) (PEDOT) and N,N’-bis-(1-naphthyl)-N,N’-diphenyl-1,10-biphenyl-4-4’-diamine (NPB). The diodes were composed of a single emissive-layer (EML), with 0.5 wt% red 4-(dicyanomethylene)-2-tbutyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran doped in a mixed-host of 25% trans-1,2-bis(6-(N,N-di-p-tolylamino)-Naphthalene-2-yl)ethene and 75% 1-butyl-9,10-naphthalene-anthracene. The device structure comprised a 125 nm anode layer of indium tin oxide, a 25 nm first HTL of PEDOT, a 0 to 10 nm second HTL of NPB, a 30 nm EML, a 40 nm electron-transporting-layer of 2,2’,2”-(1,3,5-benzenetriyl)-tris(1-phenyl-1-H-benzimidazole), a 1 nm electron-injection-layer of lithium fluoride and a 150 nm cathode layer of aluminum. With the addition of a 7.5 nm second HTL (NPB), the resultant power-efficiency at 100 cd/m

The EtOAc extract of a Taiwanese soft coral, Caldiella australis, yielded four new eunicellin-based diterpenoids, australins A-D (1-4). The chemical structures of these metabolites were determined on the basis of extensive spectroscopic (including 1D and 2D NMR) analyses and by comparison of their NMR spectral data with those of related metabolites. Metabolite 2 was found to possess a moderate cytotoxic activity against selected breast and liver cancer cell lines.

We present an alternative scheme for determining the frequencies of cesium (Cs) atom 6S-8S Doppler-free transitions. With the use of a single electro-optical crystal, we simultaneously narrow the laser linewidth, lock the laser frequency, and resolve a narrow spectrum point by point. The error budget for this scheme is presented, and we prove that the transition frequency obtained from the Cs cell at room temperature and with one-layer μ-metal shielding is already very near that for the condition of zero collision and zero magnetic field. We point out that a sophisticated linewidth measurement could be a good guidance for choosing a suitable Cs cell for better frequency accuracy.

We demonstrate organic light-emitting diodes (OLEDs) capable of yielding sunlight-style illumination with various daylight chromaticities, whose color temperature (CT) covers those of the daylight at different times and regions. Besides having the disruptive characters like being plane-type and luminaire-ready, flexible, printable, thin, and light, the emissive spectrum of OLEDs closely resembles that of sunlight. The degree of sunlight spectrum resemblance is 63%, for example, for one high color rendering OLED, while 2% for a sodium lamp, 16% for a fluorescent tube, 49% for a light-emitting diode, and 72% for an incandescent bulb. By incorporating one hole-modulating layer (HML), a fluorescent sunlight-style OLED yields CT between 2300 and 7900 K, while the CT span can be further expanded between 2400 and 18000 K by using double HMLs. For a phosphorescent sunlight-style OLED, the CT spans between 1900 and 3100 K with a power efficiency of 17.6 lm/W at 1000 cd/m2.

This study reports the fabrication of a highly efficient, very high color-rendering index (CRI) white organic light-emitting diode (OLED) using five organic dyes doped into two different phosphorescent and fluorescent emissive layers separated by a high triplet-energy interlayer. The resulting white OLED achieves a 93 CRI with a power efficiency of 23.3 lm W−1 at 100 cd m−2, or 14.3 lm W−1 at 1000 cd m−2. This high CRI is attributable to the five dyes employed in this design, which together emit a relatively wide spectrum that nearly covers the entire range of visible light. At the proper thickness, the interlayer enables the device to balance the distribution of carriers in the two emissive zones and achieve a maximum power efficiency while maintaining high CRI.

This study demonstrates a highly efficient orange-red organic light-emitting diode with a double emissive layer architecture that exhibits a record-breaking power efficiency of 47 lm W−1 at 100 cd m−2, or 32 lm W−1 at 1 000 cd m−2. Two factors may contribute to the high efficiency. First, the device architecture has a stepwise energy-level, leading to a significantly reduced energy-barrier for both hole and electron to transport, revealed by the relatively low driving voltage. Second, employing a hole-transporting host and an electron-transporting host leads to a nearly perfect balanced injection of hole and electron to the emissive zones, indicated by the obtained external quantum efficiency that reaches the 20% theoretical limit.