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Tantalum nitride (Ta3N5) is a very promising photoanode material due to its narrow band gap (2.1 eV) and suitable band alignment for solar water splitting. However, it suffers from severe photocorrosion during water oxidation. In this work, it was found that surface passivation by AlOx and TiOx layers results in dramatically different PEC performance of Ta3N5 photoanode for water oxidation. The mechanism study indicates that the negative charges on AlOx can generate additional field to promote separation of photogenerated charges, while the positive charges on TiOx layer show the opposite effect. As a result, the Ta3N5 based photoanode modified with AlOx layer gives a high photocurrent of 12.5 mA cm−2 for 24 h at 1.23 V versus the reversible hydrogen electrode (RHE). Dynamic analysis implies that the hole extraction and transfer are significantly improved by the modification with the AlOx layer. This work reveals the importance of the charges on surface passivation layer in interface engineering of photoelectrodes.

A boomerang-shaped ultra wide band (UWB) planar antenna has been presented for spectrum sensing applications. The presented antenna has been built upon a narrow band isotropic antenna design. In or...

Рассмотрен процесс формирования радиосигнала с помощью квадратурного модулятора. Точность осуществления переноса на несущую является критически важным фактором. При передаче информационного сообщения значения сигнала несущей частоты должны принимать соответствующие дискретные значения, согласно закону изменения информационной последовательности, таким образом, формирование неискажённого радиосигнала является одним из основных требований, предъявляемых к работе квадратурного модулятора. При реализации сигналов с угловой модуляцией, как правило, используют генератор, управляемый напряжением. Проанализирована работа квадратурного модулятора и квадратурного фазового модулятора, основанного на формирователях функциональных составляющих модулирующего сигнала. Предложен метод компенсации искажений, возникающих в балансных смесителях и фазовращателе за счет быстроизменяющихся помех, приходящих с выхода высокочастотного генератора или с выхода усилителя мощности по цепи обратной связи, а также медленных отклонений фазы и амплитуды сигнала. Проведено моделирование работы схемы, осуществляющей компенсацию амплитудно-фазовых искажений квадратурного модулятора сигналов угловой модуляции за счёт генерирования компенсационных сигналов. Предложена структурная схема синтеза неискаженного сигнала амплитудно-фазовой модуляции с компенсацией амплитудно-фазовой нестабильности квадратурного формирователя, позволяющая осуществлять нелинейное усиление радиосигнала The paper considers the process of data transmission over a radio channel by modulating the parameters of the carrier wave with an information signal. When transmitting an information signal, the carrier frequency values must take discrete values in one-to-one correspondence with the information sequence, thus the formation of an undistorted radio signal is one of the main requirements for the operation of a quadrature modulator. The article analyzes the operation of a quadrature modulator and a quadrature phase modulator based on the shapers of the functional components of the modulating signal. We propose a distortion compensation method using synthesized compensation signals, which makes it possible to effectively compensate, firstly, rapidly changing noise inside balanced modulators and phase shifters, and secondly, noise coming along with an input high-frequency signal, for example, from the output of a power amplifier through circuits feedback and, third, slow deviations of amplitudes and phases. We carried out the modeling of the distortion compensation method using synthesized compensation signals

OBJECTIVES To compare the effects of Narrow band CE-Chirps (NB CE-Chirps) and tone bursts (TBs) at 500 Hz and 1000 Hz on the amplitudes and latencies in cervical vestibular evoked myogenic potentials (cVEMPs). DESIGN Thirty-one healthy adult volunteers of varying ages were tested by air conduction at 95 dB nHL. Recording conditions were randomized for each participant and each modality was tested twice. RESULTS NB CE-Chirps showed larger corrected amplitudes than TBs at 500 Hz (p < 0.001) which were themselves larger than NB CE-Chirps and TBs at 1000 Hz (p < 0.001). In older volunteers, NB CE-Chirps 500 and 1000 Hz had significantly higher response rates than TBs 500 Hz (p = 0.039). A negative correlation was observed between the corrected amplitudes and the age of the participants regardless of the stimulus and the frequency studied. The p13 and n23 latencies were not correlated with the age of the subjects. CONCLUSIONS NB CE-Chirps at 500 Hz improved the corrected amplitudes of waveforms in cVEMPs as a result of a better frequency specificity compared with TBs. In the elderly, eliciting cVEMPs at a frequency of 1000 Hz might not be necessary to improve response rates with NB CE-Chirps. Additional studies including a higher number of healthy participants and patients with vestibular disorders are required to confirm these observations.

CsPbCl3 nanocrystals are potential ultrapure emitters. But it is challenging to synthesize CsPbCl3 nanocrystals with sufficient stability, which impedes their application in light-emitting devices. In this work, we report a facile phosphoryl-chemistry-mediated synthesis approach to synthesizing stable CsPbCl3 nanocrystals, in which the phenylphosphonic dichloride (PhPOCl2) precursor is employed. In addition to the high reactivity of the P–Cl bond of PhPOCl2 for providing adequate Cl, the derived P=O with good proton affinity facilitates the formation of a distinct nanocrystal surface with the nonprotonated oleylamine (OLA) ligand. Accordingly, the L-type-ligand-capped CsPbCl3 nanocrystals exhibited not only bright luminance but also good stability that endured repeated purification up to 10 cycles. Based on the stable CsPbCl3 nanocrystals, we achieved violet LEDs with extremely narrow electroluminescence spectra (full width at half-maximum ≈ 10.6 nm).

The discrete time signal processing requires an anti-aliasing filter at the input and a reconstruction filter at output. Some filters of biquads structure are characterized by a decreasing of the attenuation at high frequencies, caused by the final value of the output resistance of the operational amplifier. In this paper we discuss a design of combined BP filter without mentioned decrease. The proposed filter structure was verified by SPICE simulation.

Background The solid mediator Z-scheme heterojunctions are promising photocatalysts that have narrow band gaps to allow excitation of incorporated electrons under visible lights but with sufficient separation of the yielded electron hole-pairs and without suffering the reduction of their oxidization and reduction powers. Successful synthesis of mediator Z-scheme heterojunction acquires production of constituent semiconductors with desired Fermi levels and close contacts of the semiconductors with sandwiched metal mediator. Methods This mini-review discussed briefly the principles of photocatalyst and heterojunction photocatalysts, and then the current research and development studies on the way to design and synthesis of Z-scheme heterojunction were summarized. Significant findings Based on literature results, the perspectives to design and synthesis of a solid mediator Z-scheme for degrading specific pollutant were discussed and outlined. An illustrative example of design and synthesis of a novel Z-scheme photocatalyst, CuFe2O4/Cu/UiO66-NH2, with demonstration of its photodegradation performance of dye rhodamine 6 G, was presented at the end of the review.

Introduction: Narrow-band (NB) ultraviolet B (UVB) phototherapy has been shown to halt disease progression in vitiligo, but whether there is any difference in the response to NB-UVB seen in patients with progressive vitiligo versus non-progressive vitiligo has not been evaluated. Objectives: To evaluate the effect of NB-UVB on progressive versus non-progressive non-segmental vitiligo. Study Design: Prospective observational comparative study. Duration: April 2016-November 2017. Methods: Adult patients having non-segmental vitiligo involving 2-50% body surface area were divided into two subsets; patients developing >5 lesions in the last 1 month or >15 lesions in the last 3 months (progressive vitiligo, Group I) and patients with static disease for the last 6 months (non-progressive vitiligo, Group II). Both groups were treated with NB-UVB for 6 months (26 weeks) cumulatively and its efficacy in halting disease progression, re-pigmentation, side effects and psychosocial impact were evaluated. Results: Nineteen out of 24 patients with progressive vitiligo had arrest of disease progression. Rest five patients developed lesions at a slower pace. Group II had earlier onset of re-pigmentation, while Group I had more NB-UVB fluence (34.73 J/cm2 vs 25.2 J/cm2, P value = 0.034), more time for the fluence to be fixed (P value = 0.001) and more pruritus (P value = 0.001). Conclusions: NB-UVB has the potential to halt disease progression in some patients with progressive vitiligo; but is associated with more total NB-UVB fluence and time taken for fixing it. Progressive vitiligo patients have more pruritus as compared to patients with non-progressive vitiligo.

Background: One of the most common dermatological conditions affecting most teenagers is acne. Phototherapy was described as a therapeutic modality with low-side effects of acne vulgaris (AV). Henc...

Patients with vitiligo experience emotional and psychological stress as they undergo long-term therapy. The debilitating psychosocial effects of this disease on patients' quality of life is well-documented. This study evaluates the effect of the introduction of narrow-band ultraviolet-B (NB-UVB) therapy on the quality of life of patients with vitiligo in Almadinah Almunawwarah, KSA.Thirty-eight patients from the main dermatology center of Ohud Hospital, Almadinah Almunawwarah, were interviewed between June 2017 and March 2019 using the Dermatology Life Quality Index (DLQI) questionnaire. The interviews were conducted before and one year after the course of NB-UVB therapy, which was added as a new treatment modality to the basic therapeutic regimen of topical medications.The patients' response to vitiligo therapy was positive. The overall patient satisfaction score regarding the NB-UVB therapy was as high as 9.1 out of 10. The initial overall DLQI score (5.67 ± 0.90) markedly decreased after the NB-UVB therapy (3.08 ± 0.56), indicating a significant improvement. The patients' adherence to the follow-up visits also improved.NB-UVB therapy is effective in alleviating psychological stress and improving the quality of life of patients with vitiligo.يعاني مرضى البهاق من الضغط النفسي والعاطفي أثناء خضوعهم لعلاج طويل الأمد. والآثار النفسية والاجتماعية الموهنة لهذا المرض، التي تؤثر على جودة حياة المرضى موثقة جيدا. في هذه الدراسة، قمنا بتقييم تأثير إضافة العلاج بالأشعة فوق البنفسجية ضيقة النطاق على جودة حياة مرضى البهاق في منطقة المدينة المنورة، المملكة العربية السعودية.تمت مقابلة ٣٨ مريضا من مركز الأمراض الجلدية الرئيس في المدينة المنورة (مستشفى أحد) باستخدام نموذج مؤشر جودة الحياة للأمراض الجلدية قبل وبعد عام واحد من دورة العلاج باستخدام الأشعة فوق البنفسجية ضيقة النطاق، التي أضيفت إلى نظامهم العلاجي الأساسي مع استمرار استخدامهم للمستحضرات الدوائية الموضعية.كانت استجابة المرضى لعلاج البهاق إيجابية. النتيجة الإجمالية لرضا المرضى فيما يتعلق بالعلاج بالأشعة فوق البنفسجية ضيقة النطاق كانت مرتفعة لتصل إلى ٩.١ من ١٠. وقد انخفضت النتيجة الأولية العامة لمؤشر جودة الحياة للأمراض الجلدية (٥.٦٧± ٠.٩٠) بشكل ملحوظ بعد العلاج المتضمن استخدام الأشعة فوق البنفسجية ضيقة النطاق (٣.٠٨ ± ٠.٥٦)، مما يشير إلى وجود تحسن. كما تحسن التزام المرضى بزيارات المتابعة والجلسات العلاجية.علاج البهاق المتضمن استخدام الأشعة فوق البنفسجية ضيقة النطاق فعال في تخفيف الضغط النفسي وتحسين جودة الحياة لدى مرضى البهاق.

Michal Szczepanek, Aleksandra Frątczak, Anna Lis-Święty Department of Dermatology, School of Medicine in Katowice, Medical University of Silesia, Katowice, PolandCorrespondence: Anna Lis-ŚwiętyDepartment of Dermatology, School of Medicine in Katowice, Medical University of Silesia, Francuska 20/24, Katowice, 40-027, PolandTel +48 602720948Email annadlis@neostrada.plBackground: Localized scleroderma (LoS) is an inflammatory fibrosing disease of the connective tissue, whose esthetic sequelae are atrophic skin lesions with hyperpigmentation. The key element of diagnostic and therapeutic procedures is the assessment of the disease’s severity and damage. The study objective was to analyze the usefulness of narrow-band reflectance spectrophotometry (NBRS) to assess erythema and hyperpigmentation in LoS lesions.Materials and Methods: Erythema indexes (EI) and melanin indexes (MI) were determined with the use of DermaLab Combo skin colour probe for LoS lesions and symmetrically located areas of normal skin. Then, relative percentage differences were determined for EI and MI, which were compared with the visual assessments of erythema and hyperpigmentation according to the Localized Scleroderma Cutaneous Assessment Tool (LoSCAT).Results: A total of 84 LoS lesions were studied in 41 patients. The study showed a moderate correlations between the spectrophotometric measurements and clinical assessments of erythema as well as hyperpigmentation (Spearman correlation coefficient, r), r = 0.37; p = 0.00047 and r = 0.55; p=0.0000001, respectively.Conclusion: NBRS seems to be a useful tool to assess the severity of erythema and hyperpigmentation in LoS lesions. Further studies are required in order to compare the spectrophotometric results with other objective methods.Keywords: colour, erythema, morphea, postinflammatory hyperpigmentation

Aim. To substantiate the application of the infrared range narrow-band optical radiation and kinesiotaping combined effect in the complex treatment of patients with posterior cervical sympathetic syndrome on the basis of clinical studies. Material and methods. The dynamics of complaints for dizziness in 60 patients of two groups were evaluated using the DHI (Dizziness Handicap Inventory) and VRBQ (Vestibular Rehabilitation Benefit Questionnaire) scales, headache and pain in the neck using the visual analog scale (VAS), tinnitus, visual defocusing, nausea, vomiting, palpitations, decreased concentration and attention using the International Classification of Functioning, Disability and Health (ICF). To assess the posture, the shoulder Aksenova index was used. A duplex scan of the brachycephalic arteries and an assessment of anxiety and depression on the Sheehan and Beck scales, respectively, were used to assess blood flow through the vertebral arteries. Results. Statistically reliable data (p

A rigidly adhered nitrogen-doped BiVO4 photoanode with a narrow band gap energy (Eg = 2.35 eV) for water oxidation was developed to attain the IPCE value of 35.1% at 440 nm which is among the highe...

Joanna Narbutt,1 Janusz Krzyścin,2 Piotr Sobolewski,2 Małgorzata Skibińska,1 Marcin Noweta,1 Witold Owczarek,3 Bonawentura Rajewska-Więch,2 Aleksandra Lesiak1 1Department of Dermatology, Pediatric Dermatology and Oncology, Medical University of Łódź, Łódź, Poland; 2Institute of Geophysics, Polish Academy of Sciences, Warsaw, Poland; 3Department of Dermatology, Military Institute of Medicine, Warsaw, PolandCorrespondence: Janusz KrzyścinInstitute of Geophysics, Polish Academy of Sciences, Warsaw, 01-452, PolandTel +48-2269-15950Email jkrzys@igf.edu.plBackground: Nowadays, patients with moderate-to-severe psoriasis are treated with conventional immunosuppressants or with new biological agents. Phototherapy is the first-line treatment for patients in whom topical therapy is insufficient. Although numerous studies have been carried out, it is still difficult to predict the outcome of phototherapy in individual patients.Methods: Prior to standard narrow band (NB) ultraviolet B (UVB) phototherapy, the patients filled out a questionnaire about personal life and health status. Several standard blood tests, including selected cytokine levels, were performed before and after a course of 20 NB-UVB treatments. The questionnaire answers, results of the blood tests, and treatment outcomes were analyzed using an artificial intelligence approach—the random forest (RF) classification tool.Results: A total of 82 participants with moderate-to-severe psoriasis were enrolled. Prior to starting phototherapy, the patients with expected good outcome from the phototherapy, shorter remission, and quitting a possible second course of the NB-UVB treatment could be identified by the RF classifier with sensitivity over 84%, and accuracy of 75%, 85%, and 79%, respectively. The inclusion of cytokine data did not improve the performance of the RF classifier.Conclusion: This approach offers help in making clinical decisions by identifying psoriatic patients in whom phototherapy will significantly improve their skin, or those in whom other therapies should be recommended beforehand.Keywords: psoriasis, phototherapy, outcome prediction, artificial intelligence

Relay attacks pose a serious security threat to wireless systems, such as, contactless payment systems, keyless entry systems, or smart access control systems. Distance bounding protocols, which allow an entity to not only authenticate another entity but also determine whether it is physically close by, effectively mitigate relay attacks. However, secure implementation of distance bounding protocols, especially of the time critical challenge-response phase, has been a challenging task. In this paper, we design and implement a secure and accurate distance bounding protocol based on Narrow-Band signals, such as Bluetooth Low Energy (BLE), to particularly mitigate relay attacks. Narrow-Band ranging, specifically, phase-based ranging, enables accurate distance measurement, but it is vulnerable to phase rollover attacks. In our solution, we mitigate phase rollover attacks by also measuring time-of-flight (ToF) to detect the delay introduced by such attacks. Therefore, our protocol effectively combines the best of both worlds: phase-based ranging for accuracy and time-of-flight (ToF) measurement for security. To demonstrate the feasibility and practicality of our solution, we prototype it on NXP KW36 BLE chips and evaluate its performance and relay attack resistance. The obtained precision and accuracy of the presented ranging solution are 2.5 cm and 30 cm, respectively, in wireless measurements. ispartof: IACR Transactions on Cryptographic Hardware and Embedded Systems vol:2021 issue:2 pages:106-135 status: published

Introduction Narrow band ultraviolet B (NB-UVB) and psoralen-ultraviolet A (PUVA) remain inexpensive and effective anti-psoriatic therapies adopted worldwide with different frequency protocols. We aimed to systematically assess the evidence on the effects of different frequency protocols of phototherapy in treating psoriasis. Evidence acquisition We used the following terms, namely "photochemotherapy", "phototherapy", "psoriasis", "UVB", "UVA" and "ultraviolet therapy", to search the Cochrane Controlled Register of Trials, MEDLINE and Embase databases on August 1, 2019. We organized results using a PRISM diagram and analyzed bias risks with RoB-2 tool. Evidence synthesis We included five randomized controlled trials (RCTs) on oral PUVA and three RCTs on NB-UVB. The five studies on PUVA included a total of 1452 patients with plaque psoriasis and did not find any significant difference in efficacy comparing two- vs. three- vs. four times weekly protocols. The three studies on NB-UVB included a total of 248 patients with plaque psoriasis. No differences in efficacy were reported in comparing different frequencies in delivering NB-UVB, namely twice vs. thrice weekly, twice vs. four times weekly, and thrice- vs. five times weekly protocols. Although protocols with higher treatments frequency per week achieved clearance faster than lower frequency ones, but they did not differ in terms of efficacy. Conclusions PUVA and NB-UVB remain an effective anti-psoriatic treatment; however further studies are needed to elucidate which protocol may be more effective in different skin phototypes.

Intravenous immunoglobulins (IVIg) are increasingly being used to treat a wide spectrum of dermatological and neurological autoimmune diseases. Although the administration of IVIg does not usually result in severe adverse reactions, side effects of IVIg reportedly occur in 6-13% of patients. Most reported cases were not severe, and IVIg is considered a relatively safe drug. Some reports described a vesicular eczematous eruption caused by IVIg that was cured by applying topical steroid ointments or systemic steroids. Herein, we present, to the best of our knowledge, the first case of severe vesicular eczematous eruption all over the body induced by IVIg that was unresponsive to topical steroid ointment and was subsequently treated with narrow band-ultraviolet B (NB-UVB) therapy successfully. NB-UVB was started at a dose of 400 mJ/cm2 once a week, and swift improvement was observed. The skin rash disappeared in the first 2 months, and the pathogenesis of IVIg-induced eczematous eruption remains unelucidated. No change in eosinophils and complement levels were observed in our case. Given the increase in the widespread use of IVIg, we have shown that NB-UVB therapy is a candidate choice for the treatment of IVIg-induced severe vesicular eczematous eruption.

Background Non-magnifying endoscopy with narrow-band imaging (NM-NBI) has been frequently used in routine screening of esophagus squamous cell carcinoma (ESCC). The performance of NBI for screening of early ESCC is, however, significantly affected by operator experience. Artificial intelligence may be a unique approach to compensate for the lack of operator experience. Aim To construct a computer-aided detection (CAD) system for application in NM-NBI to identify early ESCC and to compare it with our previously reported CAD system with endoscopic white-light imaging (WLI). Methods A total of 2167 abnormal NM-NBI images of early ESCC and 2568 normal images were collected from three institutions (Zhongshan Hospital of Fudan University, Xuhui Hospital, and Kiang Wu Hospital) as the training dataset, and 316 pairs of images, each pair including images obtained by WLI and NBI (same part), were collected for validation. Twenty endoscopists participated in this study to review the validation images with or without the assistance of the CAD systems. The diagnostic results of the two CAD systems and improvement in diagnostic efficacy of endoscopists were compared in terms of sensitivity, specificity, accuracy, positive predictive value, and negative predictive value. Results The area under receiver operating characteristic curve for CAD-NBI was 0.9761. For the validation dataset, the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of CAD-NBI were 91.0%, 96.7%, 94.3%, 95.3%, and 93.6%, respectively, while those of CAD-WLI were 98.5%, 83.1%, 89.5%, 80.8%, and 98.7%, respectively. CAD-NBI showed superior accuracy and specificity than CAD-WLI (P = 0.028 and P ≤ 0.001, respectively), while CAD-WLI had higher sensitivity than CAD-NBI (P = 0.006). By using both CAD-WLI and CAD-NBI, the endoscopists could improve their diagnostic efficacy to the highest level, with accuracy, sensitivity, and specificity of 94.9%, 92.4%, and 96.7%, respectively. Conclusion The CAD-NBI system for screening early ESCC has higher accuracy and specificity than CAD-WLI. Endoscopists can achieve the best diagnostic efficacy using both CAD-WLI and CAD-NBI.

The exploration of narrow-emitting phosphors in the red, green, and blue spectral region is of great significance for improving the color gamut of liquid-crystal displays (LCD). In this work, a nar...

Background and Objectives: The aim of the study was to compare effects of tone-burst (TB) and narrow-band (NB) Claus Elberling (CE)-chirp stimuli on amplitude, latency and interaural asymmetry ratio (IAR) of cervical vestibular evoked myogenic potentials (cVEMP) in healthy individuals.Subjects and Methods: The study included 50 healthy volunteers. cVEMP procedure was carried out using 500 Hz TB and NB-CE-chirp stimulus (360-720 Hz, up-chirp) in random order. cVEMP were recorded at 100 dB nHL. For each ear and each stimulus, P1 latency, N1 latency and P1N1 amplitude were measured. IAR was also calculated.Results: Mean age was 26.66±9.48 years. cVEMP’s in response to both TB and NB CE-chirp stimuli were obtained in all subjects. No statistically significant difference in P1 latency, N1 latency, and P1N1 amplitude was found between the right and left ears for both TB and NB CE-chirp stimuli (p>0.05). In both sides, P1 and N1 latencies were significantly shorter in NB CE-chirp stimulation compared to TB stimulation (p=0.000). In both sides, no statistically significant difference was found in P1N1 amplitude between two types of stimuli (p>0.05).Conclusions: The chirp stimulus produces robust but earlier cVEMP than TB does. This largest series study on NB chirp cVEMP shows that NB chirp is a good and new reliable alternative.

The correlation and spectral properties of a multicomponent narrowband periodical non-stationary random signal (PNRS) and its Hilbert transformation are considered. It is shown that multicomponent narrowband PNRS differ from the monocomponent signal. This difference is caused by correlation of the quadratures for the different carrier harmonics. Such features of the analytic signal must be taken into account when we use the Hilbert transform for the analysis of real time series.

Folded quad-mode stub-loaded loop resonators (QMSLLRs) are proposed for realizing both bandpass and dual-band bandpass filters with compact dimensions. The QMSLLR is a folded square loop loaded with four short stubs, providing structure symmetry in both transversal and longitudinal directions. Determined by the lengths of the loaded stubs, the four resonant frequencies as analyzed with even-odd mode method can be either distributed in one passband with equal space, or in two passbands with a guard band in between, for realizing a single-band bandpass filter or a dual-band bandpass filter, respectively. For both the input and output couplings, two perpendicular feeding lines are parallel coupled to the QMSLLR at one corner. The measure results prove that the structure is suitable for the design of a medium band or even narrow band bandpass filters with compact dimensions.

To overcome the problem that Bi3+-activated phosphors suffer from, it is an urgent need to realize narrow-band light emission of Bi3+-activated phosphors, which not only improves their luminescence...

Molybdenum diselenide (MoSe2) is a promising gas sensing material due to its large surface-to-volume ratio, narrow band gap, and excellent absorptions. However, MoSe2-based gas sensors possess infe...

Over the last decade, narrow-band emitters have been recognized as key enablers for light emitting diodes (LEDs) backlights in liquid-crystal displays (LCDs) by competing with other display technologies. Today, efforts have been devoted to the exploration of narrow-band green/red luminescent materials with high quantum efficiency and excellent stability to optimize the performance of LED backlights. This review first presents an overview of the significant progress made in the development of narrow-band emitters used in LED backlights for LCDs with the emphasis on the versatile materials databases from doped phosphors to luminescent II–VI, III-V semiconductor quantum dots, and the recent halide perovskites nanocrystals and bulk metal halides. Subsequently, the correlation of structure-luminescence properties, and the device performance optimization of these emitters have been analyzed. The focus is placed on summarizing and comparing the remarkable examples of outdated and new narrow-band luminescent materials as potential candidates in LED backlights. Finally, the outlooks and challenges in discovering new narrow-band emitters have been proposed.

Currently, high-performance organic solar cells (OSCs) are mainly composed of narrow band gap (NBG) nonfullerene acceptors and medium band gap (MBG) polymer donors, whereas the solar cells based on...

Venture capital is associated with some of the most high-growth and influential firms in the world. Academics and practitioners have effectively articulated the strengths of the venture model. At the same time, venture capital financing also has real limitations in its ability to advance substantial technological change. Three issues are particularly concerning to us: 1) the very narrow band of technological innovations that fit the requirements of institutional venture capital investors; 2) the relatively small number of venture capital investors who hold and shape the direction of a substantial fraction of capital that is deployed into financing radical technological change; and 3) the relaxation in recent years of the intense emphasis on corporate governance by venture capital firms. While our ability to assess the social welfare impact of venture capital remains nascent, we hope that this article will stimulate discussion of and research into these questions.

Organic light-emitting diodes utilizing thermally activated delayed fluorescence sensitizers and multiple-resonance (MR) dopants may simultaneously offer high efficiencies and narrow-band emissions...

Metamaterials are designed and manufactured artificially to manifest intriguing physical concepts and achieve unusual potential applications. However, the exotic properties of metamaterials normally originate from the resonance mechanism of artificial atoms, thus inevitably limited in narrow band and hindering their practical applications. Here, we numerically design and experimentally verify a novel tunable dielectric metamaterial based on strontium titanate artificial atoms to alleviate the bandwidth restriction of resonance metamaterial. By control of the magnetic resonance with the electric resonance, the tunable dielectric metamaterial can broaden the practical applications of metamtaterials and play an important role in all-optical communication devices.

Background Neopterin is a cellular immunity biochemical marker. Serum and saliva neopterin levels have been reported to increase in lichen Planus. Nonetheless, analysis has not yet been made for the direct link between narrow band ultraviolet B and severity of Lichen planus. Aim We aimed to assess serum neopterin levels in patients who receive narrow band ultraviolet B therapy treatment with lichen planus, paired with the severity of the disease. Patients and methods The study consisted of 35 lichen planus patients and 30 healthy individuals. A 35 patient group received narrow band ultraviolet B therapy. An enzyme-related immunosorbent assay procedure was used in serum neopterin analysis before and post-therapy. Results The correlation between the level and severity of the patient group was statistically significant (P = .001). In patients with severe disease, serum neopterin levels were significantly increased. Also, in the severe lichen planus group, the serum neopterin level was statistically higher than that of the mild or moderate groups (P = .001).Also, a significant decrease was seen following therapy according to serum neopterin level. Conclusion Serum neopterin levels are a useful marker for the assessment of the severity and effectiveness of narrow band ultraviolet therapy. Thus, our findings may provide a new approach with the management of disease and follow-up strategies in patients with lichen planus.

The semitransparent flexible organic solar cell takes advantages of flexibility, transparency, color adjustment property, which is more conducive to integrate on buildings and mobile terminals. Ascribing to the developments of narrow band gap donors and the new non-fullerene acceptors, the power conversion efficiency of semitransparent flexible organic solar cells has been achieved 10% to 12% with average visible transmittance of 17% to 21%. This review summarizes the molecular design of the most representative active layer materials, and discusses the characterization of semitransparent parameters paradigms, then we discuss how to optimize the device in combination with optical simulation, and finally list the recent development of semitransparent flexible electrodes of ITO-free organic solar cells, and give our perspectives on the next step direction.

A transient pulsed arc was studied with narrow band 696.5 nm filters. The arc energy distribution was considered by a ratio: a certain region energy (intensity × region area)/sum. The results indic...

This work is the continuation of our previous work entitled "Investigations on optical, material and electrical properties of aSi:H and aSiGe:H in making proposed n+aSi:H/iaSi:H/p+aSiGe:H graded band gap solar cells." In this work, we present an additional bottom layer made of increased germanium content: aSi0.64Ge0.36:H to the previously recommended p+aSi:H/i-aSi:H/n+aSi0.73Ge0.27:H photovoltaic cell to strengthen the absorption spectrum and thereby boosting the attainment of the solar cell. Moreover, the overall active layer thickness is reduced from 430 nm of previous work to 395 nm of proposed work. This work includes the fabrication of samples of epitaxially grown aSiGe:H thin films of varying band gap made with Plasma Enhanced Chemical Vapour Deposition (PECVD) technique succeeded by their characterisation. The establishment of band gap tailoring by varying the germane (GeH4) gas flow rate is thoroughly investigated through optical characterisation. The growth chemistry of PECVD made aSi0.64Ge0.36:H layer has been analysed and the presence of respective radicals has been verified using Fourier Transform Infra Red (FTIR) spectroscopy. In accordance with the measured band gaps, p+ aSi:H/i-aSi:H/n+aSi0.73Ge0.27:H/naSi0.64Ge0.36:H solar cell has been proposed. A comprehensive inquiry on optimisation of the recommended structure has been made by varying the optical band gap and thickness of the bottom most aSi0.64Ge0.36:H layer of the structure. All the cell parameters including open circuit voltage (Voc), short circuit current density (Jsc), maximum power point voltage (Vm), maximum power point current density (Jm), Fill factor (FF) and conversion efficiency (η) has been calculated using SCAPS1D solar simulator. Furthermore, C–V characteristics and Mott-Schottky plot of the proposed structure has been evaluated. The introduction of narrow band gap amorphous silicon germanium (aSi0.64Ge0.36:H) at the bottom has remarkably enhanced Jsc and η to 15.54 mA/cm2 and 15.15% respectively, which is better compared to reported amorphous silicon photovoltaic cells having single junction.

This paper presents analytic and numerical modelling of a MEMS electrodynamic micro-sensor of dynamic pressure. Two coaxial planar inductors of different diameters are used in the proposed micro-sensor design. Using finite element analysis, the diaphragm resonant frequency and dynamic displacements are evaluated for different diaphragm thicknesses. Then, the total sensitivity is deduced by coupling different physical domains which contribute in the micro-sensor operation. A lumped element model is built in order to study the micro-sensor sensitivity and define the dynamic performance for different resonant frequencies. This model shows that the best sensitivity, within the mV/Pa range, is obtained around the resonant frequency when operation in the audible frequency range, and decreases to the uV/Pa range for ultrasonic frequencies. The obtained sensitivity curves prove that the undamped inductive micro-sensor can offer high pressure sensitivity within a narrow frequency bandwidth.

Complex bismuth chalcogenides are narrow band gap semiconductors with intrinsic low thermal conductivity, which exhibit high potential as highly efficient thermoelectric materials. Here, we assess ...