Two-step

两步
  • 文章类型: Journal Article
    开发用于柔性大面积钙钛矿太阳能电池(PSC)和模块的稳定的卷对卷(R2R)工艺是一项紧迫的挑战。在这项研究中,我们介绍了一种新的R2RPSC制造系统,该系统采用两步沉积方法涂覆钙钛矿,并使用强脉冲光(IPL)进行退火。该系统已经成功地制造了小尺寸的细胞和有史以来第一个大尺寸,R2R处理的柔性模块。我们工作的重点是加速PbI2向钙钛矿的转化。为此,我们利用IPL退火并将添加剂掺入到PbI2层中。有了这些修改,R2R处理的钙钛矿薄膜实现了16.87%的功率转换效率(PCE),代表R2R两步处理PSC的最高报告值。然而,这些细胞在反向和正向PCE测量中表现出滞后现象。为了解决这个问题,我们引入了由IPL组成的双重退火过程,然后进行2分钟的加热步骤。这种方法成功地减少了滞后,导致低滞后,R2R处理的柔性PSC。此外,我们使用双退火系统制造了PCE为11.25%的大型柔性模块(10×10cm2),标志着这一领域的重要里程碑。
    The development of a stable roll-to-roll (R2R) process for flexible large-area perovskite solar cells (PSCs) and modules is a pressing challenge. In this study, we introduced a new R2R PSC manufacturing system that employs a two-step deposition method for coating perovskite and uses intensive pulsed light (IPL) for annealing. This system has successfully fabricated small-sized cells and the first-ever large-sized, R2R-processed flexible modules. A key focus of our work was to accelerate the conversion of PbI2 to perovskite. To this end, we utilized IPL annealing and incorporated additives into the PbI2 layer. With these modifications, the R2R-processed perovskite films achieved a power conversion efficiency (PCE) of 16.87%, representing the highest reported value for R2R two-step processed PSCs. However, these cells exhibited hysteresis in reverse and forward PCE measurements. To address this, we introduced a dual-annealing process consisting of IPL followed by a 2-min thermal heating step. This approach successfully reduced hysteresis, resulting in low-hysteresis, R2R-processed flexible PSCs. Moreover, we fabricated large-scale flexible modules (10 × 10 cm2) with a PCE of 11.25% using the dual-annealing system, marking a significant milestone in this field.
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  • 文章类型: Journal Article
    聚乙烯吡咯烷酮混合在不同浓度的PbI2中,从而研究两步生长法过程中钙钛矿的粗化动力学。观察到聚乙烯吡咯烷酮阻碍了PbI2的结晶,并有助于形成更无定形的PbI2基质,然后改善钙钛矿结晶。随着混合浓度从0增加到2mM,钙钛矿的平均微晶/晶粒尺寸从40.29nm/0.79µm增加到84.35nm/1.02µm,而表面波动从25.64nm略微减小到23.96nm。观察结果是由聚乙烯吡咯烷酮对PbI2带来的“限制效应”引起的。提高聚乙烯吡咯烷酮的混合浓度导致更小的PbI2微晶和更无定形的PbI2基质,因此减少了PbI2和有机盐之间的扩散/反应障碍,有利于钙钛矿结晶。随着混合浓度从0增加到2mM,器件效率从19.76(±0.60)%上升到20.50(±0.89)%,优化值高达22.05%,经过正辛基碘化铵(OAI)的表面改性,进一步提高到24.48%。该研究扩大了聚合物分子带来的“约束效应”的范围,有利于高效稳定的钙钛矿太阳能电池的制造。
    Polyvinyl pyrrolidone is blended in PbI2 with varied concentration, so as to study the coarsening dynamics of perovskite during the two-step growth method. It is observed that polyvinyl pyrrolidone hinders the crystallization of PbI2 and helps to form a more amorphous PbI2 matrix, which then improves perovskite crystallization. As the blending concentration increases from 0 to 2 mM, average crystallite/grain size of perovskite increases from 40.29 nm/0.79 µm to 84.35 nm/1.02 µm while surface fluctuation decreases slightly from 25.64 to 23.96 nm. The observations are caused by the \"confinement effect\" brought by polyvinyl pyrrolidone on PbI2 . Elevating blending concentration of polyvinyl pyrrolidone results in smaller PbI2 crystallites and more amorphous PbI2 matrix, thus reducing the diffusion/reaction barrier between PbI2 and organic salt and favoring perovskite crystallization. As blending concentration increases from 0 to 2 mM, the device efficiency rises from 19.76 (± 0.60) % to 20.50 (± 0.89) %, with the optimized value up to 22.05%, which is further improved to 24.48% after n-Octylammonium iodide (OAI)-basing surface modification. The study enlarges the scope of \"confinement effect\" brought by polymer molecules, which is beneficial for efficient and stable perovskite solar cell fabrication.
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  • 文章类型: Journal Article
    目的:腹腔镜可调节胃束带(LAGB)具有较高的技术和体重减轻失败率。我们在这里评估1年发病率,死亡率,和减重腹腔镜下Roux-en-Y-胃旁路术(LRYGB)作为一种可行的转换策略。
    方法:从我们中心的电子数据库中选择2004年7月至2019年12月接受LRYGB的原发性LAGB失败患者。患者同时(一阶段方法)或其间至少3个月(两阶段方法)转换为LRYGB。主要结果包括30天发病率和死亡率。次要结果是体重指数(BMI),过量体重减轻百分比(%EWL),以及术后1年超重体重指数丢失百分比(%EBMIL)。
    结果:我们中心共有1295名患者从LAGB转换为LRYGB:一个阶段有1167名患者(90.1%),两个阶段有128名患者(9.9%)。没有死亡。术后早期(30天)并发症发生在93例(7.2%),组间无显著差异。出血是39例患者中最常见的并发症(3.0%),19例患者(1.4%)需要再次手术。术后1年,平均BMI为28.0kg/m2,平均%EWL为72.8%,和平均%EBMIL87.0%。组间无统计学差异。
    结论:转用LRYGB可以被认为是一种安全有效的选择,在1年时并发症发生率低,体重减轻效果好。一阶段转换提供与合格外科医生的两步手术相同的早期结果。
    Laparoscopic adjustable gastric band (LAGB) has high technical and weight loss failure rates. We evaluate here the 1-year morbidity, mortality, and weight loss of laparoscopic Roux-en-Y-gastric bypass (LRYGB) as a feasible conversion strategy.
    Patients with a failed primary LAGB who underwent LRYGB from July 2004 to December 2019 were selected from an electronic database at our center. Patients had a conversion to LRYGB at the same time (one-stage approach) or with a minimum of 3 months in between (two-stage approach). Primary outcomes included 30-day morbidity and mortality. Secondary outcomes were body mass index (BMI), percent excess weight loss (%EWL), and percent excess BMI lost (%EBMIL) at 1 year postoperatively.
    A total of 1295 patients underwent a conversion from LAGB to LRYGB at our center: 1167 patients (90.1%) in one stage and 128 patients (9.9%) in two stages. There was no mortality. An early (30-day) postoperative complication occurred in 93 patients (7.2%), with no significant difference found between groups. Hemorrhage was the most common complication in 39 patients (3.0%), and the reoperation was required in 19 patients (1.4%). At 1 year postoperatively, the mean BMI was 28.0 kg/m2, the mean %EWL 72.8%, and the mean %EBMIL 87.0%. No statistically significant difference was found between the groups.
    Conversion to LRYGB can be considered as a safe and effective option with low complication rate and good weight loss outcomes at 1 year. One-stage conversion provides the same early outcome as two-step surgery with a competent surgeon.
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  • 文章类型: Journal Article
    由于传统的单斜率和串行两步模数转换器(ADC)中的速度限制,高帧速率CMOS图像传感器(CIS)在行业中的应用要求尚未得到满足。在本文中,提出了一种面向CIS的高速全差分两步ADC设计方法。该方法基于差分斜坡和时间数字转换(TDC)技术。形成了与串行转换不同的并行转换模式,并且由于差分斜坡的存在,保证了系统的鲁棒性。针对传统TDC技术与单斜率ADC的不一致,提出了一种基于电平编码的TDC技术。所提出的技术在模数转换的最后一个时钟周期中实现了TDC,并在另一个层面实现了两步转换过程。本文给出了一个完整的电路设计,布局设计,并基于55nm1P4MCMOS实验平台对所提设计办法停止了测试验证。在模拟电压为3.3V的设计环境下,1.2V的数字电压,100MHz的时钟频率,和1.6V的动态输入范围,该设计是一个转换时间为480ns的12位ADC,列级功耗为62μW,+0.6/-0.6LSB的微分非线性(DNL),和+1.2/-1.4LSB的积分非线性(INL)。此外,它实现了70.08dB的信噪比(SNDR)。所提出的设计提供了具有高帧率的大面积阵列,与现有先进的单斜率ADC相比,其转换速度提高了52%以上。为实现高帧频率CIS提供了有效的解决方案。
    The application requirements of high frame rate CMOS image sensors (CIS) in the industry have not been satisfied due to the speed limitations in traditional single-slope and serial two-step analog-to-digital converters (ADCs). In this paper, a high-speed fully differential two-step ADC design method for CIS was proposed. The proposed method was based on differential ramp and time-to-digital conversion (TDC) technology. A parallel conversion mode was formed that is different from serial conversion, and the robustness of the system was ensured due to the existence of differential ramps. Aiming at the inconsistency between traditional TDC technology and single-slope ADC, a TDC technology based on level coding was proposed. The proposed technology achieves the TDC in the last clock cycle of analog-to-digital conversion, and realized a two-step conversion process at another level. This paper presents a complete circuit design, layout design, and test verification of the proposed design method based on the 55 nm 1P4M CMOS experimental platform. Under the design environment of the analog voltage of 3.3 V, the digital voltage of 1.2 V, the clock frequency of 100 MHz, and a dynamic input range of 1.6 V, this design was a 12-bit ADC with a conversion time of 480 ns, column-level power consumption of 62 μW, differential nonlinearity (DNL) of +0.6/-0.6 LSB, and integral nonlinearity (INL) of +1.2/-1.4 LSB. Furthermore, it achieved a signal-to-noise distortion ratio (SNDR) of 70.08 dB. The proposed design provided a large area array with a high frame rate, and compared with the existing advanced single-slope ADC, its conversion speed increased by more than 52%. It provides an effective solution for the implementation of high frame frequency CIS.
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  • 文章类型: Journal Article
    采用最终等温温度低于MS的两步贝氏体处理,以获得具有丰富残留奥氏体(RA)的贝氏体钢。采用纳米压痕试验研究了RA在贝氏体钢中的稳定性,阐明了RA对中碳钢变形的影响。结果表明,与传统的一步法相比,使用两步处理获得了更大量的纳米级RA膜。这是由于较低的最终贝氏体转变温度,在停滞阶段,未转化奥氏体中的碳浓度更高;这导致未转化奥氏体的碳含量更高,而不是在随后的冷却过程中形成马氏体。此外,确定在两步转换过程中RA的稳定性增加延迟了突出点。
    A two-step bainitic treatment with a final isothermal temperature below MS was adopted to obtain bainitic steel with abundant retained austenite (RA). Nanoindentation testing was used to investigate the stability of RA in bainite steel and clarify the effect of RA on the deformation of medium-carbon steel. The results showed that, in contrast to the traditional one-step approach, a greater amount of nanoscale RA film was obtained using the two-step treatment. This was due to a lower final bainitic transformation temperature, which induced a higher carbon concentration in the untransformed austenite in the stasis stage; this resulted in untransformed austenite with a higher carbon content existing as RA rather than forming martensite in the subsequent cooling process. In addition, it was determined that the increased stability of RA during the two-step transformation delayed the pop-in point.
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  • 文章类型: Journal Article
    未经评估:需要准确的预后评分来预测COVID-19感染成人的死亡率,以了解谁将从住院和更密集的支持和护理中受益最大。我们的目标是开发和验证用于患者分诊的两步评分系统,并使用易于收集的个人信息来识别死亡率风险相对较低的患者。
    UNASSIGNED:多中心回顾性观察性队列研究。
    UNASSIGNED:弗吉尼亚联邦大学的四个健康中心,乔治敦大学,佛罗里达大学,和加州大学,洛杉矶.
    未经批准:2019年冠状病毒病确诊和住院的成年患者。
    UNASSIGNED:我们纳入了来自弗吉尼亚联邦大学(VCU)的1,673名参与者作为推导队列。在重复缺失数据填补后,使用多变量逻辑模型和变量选择程序确定住院死亡的危险因素。开发了两步风险评分,以识别较低的患者,中度,和更高的死亡风险。第一步选择增加年龄,不止一种预先存在的合并症,心率>100次/分钟,呼吸频率≥30次呼吸/分钟,和SpO2<93%进入预测模型。除了年龄和SpO2,第二步使用血尿素氮,中性粒细胞绝对计数,C反应蛋白,血小板计数,和中性粒细胞与淋巴细胞比率作为预测因子。C-statisticsreflectedverygooddistinctionwithinternalvalidationatVCU(0.83,95%CI0.79-0.88)andexternalvalidationattheotherthreehealthsystems(range,0.79-0.85)。还推导了一步模型进行比较。总的来说,两步风险评分的表现优于一步风险评分.
    UNASSIGNED:广泛使用的两步评分系统,COVID-19患者分诊的护理点数据,在实践中是一种潜在的节省时间和成本的工具。
    UNASSIGNED: An accurate prognostic score to predict mortality for adults with COVID-19 infection is needed to understand who would benefit most from hospitalizations and more intensive support and care. We aimed to develop and validate a two-step score system for patient triage, and to identify patients at a relatively low level of mortality risk using easy-to-collect individual information.
    UNASSIGNED: Multicenter retrospective observational cohort study.
    UNASSIGNED: Four health centers from Virginia Commonwealth University, Georgetown University, the University of Florida, and the University of California, Los Angeles.
    UNASSIGNED: Coronavirus Disease 2019-confirmed and hospitalized adult patients.
    UNASSIGNED: We included 1,673 participants from Virginia Commonwealth University (VCU) as the derivation cohort. Risk factors for in-hospital death were identified using a multivariable logistic model with variable selection procedures after repeated missing data imputation. A two-step risk score was developed to identify patients at lower, moderate, and higher mortality risk. The first step selected increasing age, more than one pre-existing comorbidities, heart rate >100 beats/min, respiratory rate ≥30 breaths/min, and SpO2 <93% into the predictive model. Besides age and SpO2, the second step used blood urea nitrogen, absolute neutrophil count, C-reactive protein, platelet count, and neutrophil-to-lymphocyte ratio as predictors. C-statistics reflected very good discrimination with internal validation at VCU (0.83, 95% CI 0.79-0.88) and external validation at the other three health systems (range, 0.79-0.85). A one-step model was also derived for comparison. Overall, the two-step risk score had better performance than the one-step score.
    UNASSIGNED: The two-step scoring system used widely available, point-of-care data for triage of COVID-19 patients and is a potentially time- and cost-saving tool in practice.
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  • 文章类型: Journal Article
    Lead halide perovskites have been revolutionary in the last decade in many optoelectronic sectors. Their bismuth-based counterparts have been considered a good alternative thanks to their composition of earth-abundant elements, good chemical stability, and low toxicity. Moreover, their electronic structure is in a quasi-zero-dimensional (0D) configuration, and they have recently been explored for use beyond optoelectronics. A significant limitation in applying thin-film technology is represented by the difficulty of synthesizing compact layers with easily scalable methods. Here, the engineering of a two-step synthesis in an air of methylammonium bismuth iodide compact thin films is reported. The critical steps of the process have been highlighted so that the procedure can be adapted to different substrates and application areas.
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  • 文章类型: Journal Article
    UNASSIGNED: Sinistral portal hypertension (SPH) is a rare clinical syndrome. The purpose of this study was to assess the clinical outcomes and safety of splenic artery embolization (SAE) in the treatment of SPH.
    UNASSIGNED: This retrospective study included 39 SPH patients who underwent SAE treatment between August 2009 and May 2021. The cases had esophageal, gastric, or ectopic varices detected by endoscopy or enhanced CT, with symptoms or signs of upper gastrointestinal (GI) bleeding and/or postprandial fullness. Clinical symptom improvement rate, complications, and symptomatic recurrence rate were observed and analyzed after treatment.
    UNASSIGNED: All the procedures were performed successfully. Of all patients, 17 received the 2-step complete SAE procedure, 19 received only the first step of the 2-step protocol (i.e., partial splenic embolization [PSE] procedure), and the remaining three received the 1-step complete SAE procedure. After the procedures, the symptoms completely disappeared in all patients, and the main complications were post-embolization syndromes, with 27 patients (69.2%) developing a low-grade fever, 24 (61.5%) developing abdominal pain and 4 (10.3%) developing nausea or mild vomiting. During the prolonged follow-up, varicose veins were gradually reduced as detected by enhanced CT; liver function parameters and platelet count remained in the normal range. Only one patient who underwent PSE treatment developed upper GI rebleeding 7 months after the procedure.
    UNASSIGNED: Two-step complete SAE is a safe and feasible procedure for the treatment of symptomatic SPH.
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  • 文章类型: Journal Article
    OBJECTIVE: Implementation of a one-step strategy for diagnosis of active Hepatitis C virus (HCV) infection would encourage the early diagnosis and reduce the time to access antiviral treatments. The aim of this study was to evaluate the impact of a HCV one-step diagnosis compared to the traditional two-step protocol in terms of the time required for patients to be seen by specialists and the time taken to start antiviral treatment.
    METHODS: A comparative study was carried out to assess two diagnostic algorithms (one-step and two-step) for active HCV infection. Serological markers were quantified using the same serum sample to determine both anti-HCV antibodies (HCV-Ab) and HCV core antigen (HCV-cAg) by Architect i2000 SR kit. In this period, a multidisciplinary procedure was started for telematics referral of viremic patients.
    RESULTS: One-step approach reduced the time required for patient HCV diagnosis, referral to a specialist, access to treatment, and eliminated the loss of patients to follow-up. Significant differences were observed between one-step and two-step diagnosis methods in the time required for patients to be seen by a specialist (18 days [Interquartile range (IQR) = 14-42] versus 107 days [IQR = 62-148]) and for the initiation of treatment (54 days [IQR = 43-75] versus 200 days [IQR = 116-388]), mainly for patients with advanced fibrosis (35 days [IQR = 116-388] versus 126 days [IQR = 152-366]).
    CONCLUSIONS: Use of HCV-cAg has proven to be a useful tool for screening patients with active hepatitis C. The development of a multidisciplinary protocol for the communication of results improved the efficiency of the care process.
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  • 文章类型: Journal Article
    Formamidinium lead triiodide (FAPbI3) exhibits the smallest band gap among lead halide perovskites, which is more desirable for solar cell applications compared to methylammonium-based counterparts. However, it remains a big challenge to prepare phase-pure α-FAPbI3 in addition to controlling the crystal morphology during film formation. Herein, we developed a temperature-assisted crystal growth to prepare high-quality thin films of α-FAPbI3 by sequential blade coating. It is found that depositing organic cation FAI at elevated temperatures facilitates the growth of α-FAPbI3, which otherwise yields mainly a yellow δ-phase at room temperature. In parallel, the crystal morphology of the perovskite films can be effectively manipulated by taking advantage of the porous structure of PbI2. Solar cells prepared with the blade-coated α-FAPbI3 yield a champion efficiency of 18.41%, which is among the highest values for FAPbI3-only solar devices. These results suggest that two-step sequential blade deposition offers a viable approach to fabricate high-quality α-FAPbI3 films for optoelectronic applications.
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