Observation of Blue-Light Emission Band from Eu-Doped Ta₂O₅Thin Films Prepared Using Co-Sputtering

In this paper, we report on the first observation of blue-light emission bands from europium-doped tantalum pentoxide (Ta2O5:Eu) thin films prepared using a simple co-sputtering method. We prepared four specimens from one as-deposited sample, and we subsequently annealed them at 700&degC, 800&degC, 900&degC, or 1000&degC for 20 min. Four remarkable photoluminescence (PL) peaks at wavelengths of 600, 620, 650, and 700 nm due to the 5D0→7F1, 5D0→7F2, 5D0→7F3, and 5D0→7F4 transitions of Eu3+ were observed from all the specimens, and blue PL peaks around a wavelength of 450 nm were also observed from the specimens annealed at 800&degC, 900&degC, and 1000&degC. The blue PL peaks seem to be originated from the 4f65d1→4f7 transition of Eu2+. Both Eu3+ and Eu2+ ions seem to exist in our Ta2O5:Eu co-sputtered thin films annealed at temperatures from 800&degC to 1000&degC. Such Ta2O5:Eu co-sputtered thin films seem to be used as multi-functional coating films having both anti-reflection and down-conversion effects for realizing high-efficiency silicon solar cells.

Observation of Violet-Light Emission Band for Thulium-Doped Tantalum-Oxide Films Produced by Co-Sputtering

We prepared thulium-doped tantalum (V) oxide (Ta2O5:Tm) thin films using co-sputtering of two Tm2O3 pellets and a Ta2O5 disc, and we observed photoluminescence (PL) peaks not only around a wavelength of 800 nm due to the 3H4→3H6 transition of Tm3+ but also around a wavelength of 400 nm (violet) from the films after annealing for the first time. Comparatively narrow PL peaks around the wavelength of 400 nm were observed from the films annealed at 800°C and 900°C for 20 min. The peak intensity from the film annealed at 900°C was approximately four-times stronger than that from the film annealed at 800°C. The origin of the 400-nm peaks seems to be the same as our non-doped Ta2O5 thin films deposited using radio-frequency sputtering because we observe PL peaks around 400 - 430 nm from the Ta2O5 films. Such a Ta2O5:Tm co-sputtered thin film seems to be used as a multi-functional coating film having both anti-reflection and down-conversion effects for realizing a high-efficiency silicon solar cell.

The Comparison of Diagnostic Significance of Narrow Band Imaging in Contrast of White Light Endoscopy in the Assessment of Nasopharyngeal Cancer

Background: Narrow band imaging (NBI) is reported to improve the diagnostic importance of nasopharyngeal cancer. The purpose of this review was to evaluate the diagnostic significance of NBI in the literature and compare it to the conventional white light endoscopy. The use of narrow band imaging (NBI) and further technological achievements concerning the resolution and magnification of endoscopic images have in the past 15 years. With the use of NBI, superficial mucosal lesions, which may be missed by standard WLI endoscopy, can be identified easily by their neoangiogenic pattern. Objective:?To assess diagnostic value of the narrow band imaging and white light endoscopy in nasopharyngeal carcinoma and compare diagnostic values (sensitivity, specificity, positive predictive value and negative predictive value) with white light endoscopy. Search Methods: From 2010 to 2020, data was searched from electronic databases such as PubMed, web of science. We used narrow band imaging as a key word accordance with diagnostic modalities such as sensitivity, specificity, PPV and NPV and data were collected. Results: We have found mainly 6 studies have discussed about diagnostic value of endoscopy in nasopharyngeal carcinoma in the total of 2746 suspected patients. Among them, 5 studies have compared diagnostic values such as sensitivity, specificity, positive predictive value and negative predictive value between NBI and WLE. Among 5 studies, 4 studies have found higher sensitivity in NBI, 2 studies found higher 1 equal to WLE specificity in NBI. 3 studies have compared PPV and NPV between NBI and WLE. Among them, all the studies found higher PPV and NPV in NBI than WLE. Conclusion: Recently?developed narrow band imaging has a great significance in the diagnosis of nasopharyngeal carcinoma. Although NBI has also encountered some problem such as contact bleeding and darker image. So, further evaluation should be done.

Visible light induced photodegradation of organic pollutants on nitrogen and fluorine co-doped TiO_2 photocatalyst

The nitrogen and fluorine co doped TiO 2 polycrystalline powder was synthesized by calcinations of the hydrolysis product of tetra butyl titanate with ammonium fluoride. Nitrogen and fluorine co doping causes the absorption edge of TiO 2 to shift to a lower energy region. The photocatalytic activity of co doped TiO 2 with anatase phases was found to be 2 4 times higher than that of the commercial TiO 2 photocatalyst Degussa P25 for phenol decomposition under visible light irradiation. The co doped TiO 2 powders only contain anatase phases even at 1000℃. Apparently, ammonium fluoride added retarded phase transformation of the TiO 2 powders from anatase to rutile. The substitutional fluorine and interstitial nitrogen atoms in co doped TiO 2 polycrystalline powder were responsible for the vis light response and caused the absorption edge of TiO 2 to shift to a lower energy region.

基于手性超表面的宽波段圆偏振光电探测器的仿真设计

针对用于检测圆偏振光的超紧凑光电探测器的工作波段大多分布在近红外及中红外且工作波段较窄的问题,设计了一种具有较宽工作带宽的圆偏振光集成光电探测器。该探测器由石墨烯与手性超表面集成,当不同圆偏振光作用在手性超表面上时,会产生不同程度的近场光学增强,利用手性超表面在较宽波段下的强偏振依赖性来增强探测器的偏振选择性。通过时域有限差分(FDTD)仿真及优化超表面结构,手性超表面在波长为577~797nm波段内的圆二色性≥0.18。设计的圆偏振光电探测器主要工作在可见光波段,工作带宽可以达到约220nm。该探测器的设计为单一片上偏振计检测更宽波段的圆偏振光提供了新的设想。

Narrow-band imaging with magnifying endoscopy is accurate for detecting gastric intestinal metaplasia

AIM:To investigate the predictive value of narrowband imaging with magnifying endoscopy (NBI-ME) for identifying gastric intestinal metaplasia (GIM) in unselected patients. METHODS:We prospectively evaluated consecutive patients undergoing upper endoscopy for various indications, such as epigastric discomfort/pain, anaemia, gastro-oesophageal reflux disease, suspicion of peptic ulcer disease, or chronic liver diseases. Patients underwent NBI-ME, which was performed by three blinded, experienced endoscopists. In addition, five biopsies (2 antrum, 1 angulus, and 2 corpus) were taken and examined by two pathologists unaware of the endoscopic findings to determine the presence or absence of GIM. The correlation between light blue crest (LBC) appearance and histology was measured. Moreover, we quantified the degree of LBC appearance as less than 20% (+), 20%-80% (++) and more than 80% (+++) of an image field, and the semiquantitative evaluation of LBC appearance was correlated with IM percentage from the histological findings. RESULTS:We enrolled 100 (58 F/42 M) patients who were mainly referred for gastro-esophageal reflux disease/dyspepsia (46%), cancer screening/anaemia (34%), chronic liver disease (9%), and suspected celiac disease (6%); the remaining patients were referred for other indications. The prevalence of Helicobacter pylori (H. pylori ) infection detected from the biopsies was 31%, while 67% of the patients used proton pump inhibitors. LBCs were found in the antrum of 33 patients (33%); 20 of the cases were classified as LBC+, 9 as LBC++, and 4 as LBC+++. LBCs were found in the gastric body of 6 patients (6%), with 5 of them also having LBCs in the antrum. The correlation between the appearance of LBCs and histological GIM was good, with a sensitivity of 80% (95%CI:67-92), a specificity of 96% (95%CI:93-99), a positive predictive value of 84% (95%CI:73-96), a negative predictive value of 95% (95%CI:92-98), and an accuracy of 93% (95%CI:90-97). The NBI-ME examination overlooked GIM in 8 cases, but the GIM was less than 5% in 7 of the cases. Moreover, in the 6 false positive cases, the histological examination showed the presence of reactive gastropathy (4 cases) or H. pylori active chronic gastritis (2 cases). The semiquantitative correlation between the rate of LBC appearance and the percentage of GIM was 79% (P < 0.01). CONCLUSION:NBI-ME achieved good sensitivity and specificity in recognising GIM in an unselected population. In routine clinical practice, this technique can reliably target gastric biopsies.

Ku波段全腔提取相对论磁控管仿真设计

为了拓展相对论磁控管工作频段,设计了一个Ku波段高效率全腔提取相对论磁控管。该器件采用20腔阳极结构,冷腔模拟结果表明其π模工作频率约为13.5 GHz。结合全腔轴向提取技术,在电压150 kV、电流0.41 kA、工作磁场0.4 T的条件下,PIC仿真得到38 MW的仿真功率,工作频率13.47 GHz;仿真得到的功率转换效率约61.6%。仿真结果表明该器件转换效率高,结构紧凑,具有实现轻小型永磁包装的潜质。

Detailed balance limit efficiency of silicon intermediate band solar cells

The detailed balance method is used to study the potential of the intermediate band solar cell （IBSC）, which can improve the efficiency of the gi-based solar cell with a bandgap between 1.1 eV to 1.7 eV. It shows that a crystalline silicon solar ceil with an intermediate band located at 0.36 eV below the conduction band or above the valence band can reach a limiting efficiency of 54% at the maximum light concentration, improving greatly than 40.7% of the Shoekley-Queisser limit for the single junction Si solar cell. The simulation also shows that the limiting efficiency of the silicon-based solar cell increases as the bandgap increases from 1.1 eV to 1.7 eV, and the amorphous Si solar cell with a bandgap of 1.7 eV exhibits a radiative limiting efficiency of 62.47070, having a better potential.

窄带成像早期诊断鼻咽癌的价值

目的 探讨内镜窄带成像(NBI)对鼻咽癌(NPC)的诊断价值。方法 对219例疑诊NPC的患者鼻腔喷入1%麻黄素及1%丁卡因,再由同一名医师使用Olympus电子内镜(NBI和白光模式)检查鼻腔。收集被检者病理检查结果、NBI和白光下内镜诊断结果,比较2种模式下的诊断灵敏度、特异度、阳性预测值、阴性预测值和诊断符合率。结果 219例患者中,96例经病理诊断确诊为NPC,123例确诊为鼻咽慢性炎或鼻咽肉芽肿性炎。NBI和白光的诊断灵敏度(88.5%比82.3%)、阴性预测值(91.1%比83.8%)比较差异无统计学意义(χ^(2)=1.51、2.84,P> 0.05);而诊断特异度(91.9%比71.5%)、阳性预测值(89.5%比69.3%)、诊断符合率(90.4%比76.3%)比较NBI均高于白光模式(χ^(2)=17.00、12.48、15.80,P <0.05)。结论 NBI诊断NPC的特异度、阳性预测值、符合率较高,对NPC有着良好的诊断价值。

单轴拉伸下氧化锆纳米柱相变机理的分子动力学研究

通过分子动力学模拟,观察到[001]取向的四方氧化锆纳米柱在拉伸载荷下具有两个线弹性变形的应力-应变关系.这一现象是四方结构向单斜结构相变的结果 .为了进一步阐明应力-应变曲线,进行了包括晶体结构分析和原子应变计算在内的详细研究.晶格取向强烈影响塑性变形机制,即[001]和[111]取向的纳米柱在拉伸载荷下经历相变,而沿[110]取向的纳米柱导致脆性断裂.观察到显著的温度效应,随着温度从300K升高到1500K,弹性模量从573.45GPa线性降低到482.65GPa.此外,还用轻推弹性带(NEB)理论估算了相变能垒,观察到相变能垒随温度的升高而降低.这一工作将有助于加深对氧化锆的四方相到单斜相转变和纳米尺度力学行为的理解.

可见光色分复用通信系统研究与实验

针对单色光通信不便用于照明、普通白光通信频谱利用率较低的问题,设计了一个可见光色分复用通信系统。该系统在保持发光二极管(LED)正常照明功能的同时,还具备信息传递功能。在发送端,采用3种具有固定波长的LED进行调制;在接收端,使用与发送端波长相匹配的窄带滤光镜来分离各个信道的光信号。分离后的光信号经由单片光电二极管转换成电信号,这些电信号再经过与预设阈值的比较后,被微控制器接收并解码。测试结果表明:接收端的窄带滤光镜能有效区分来自3个特定波长LED的广播信号;当发送速率低于50 kHz时,眼图效果良好,能够实现稳定的通信;但当发送速率提升至50 kHz以上时,图像会出现错误色块和偏移失真。

形貌调控及掺杂改性对TiO_(2)催化剂光催化性能的影响

为了改善TiO_(2)光催化活性,通过溶胶-凝胶法制备了介孔TiO_(2)、C/TiO_(2)、Nd/TiO_(2)和C/Nd/TiO_(2),并以聚苯乙烯(PS)胶晶为模板剂制备了多级有序C/Nd/TiO_(2)催化剂。利用SEM、XRD、XPS、UV-Vis DRS和N_(2)吸附-脱附等表征手段对所制备的催化剂性能进行分析。在模拟可见光条件下研究了所制备催化剂材料对甲基橙溶液的光催化性能。结果表明,锐钛矿型多级有序C/Nd/TiO_(2)催化剂表面形貌排列整齐,内部具有交联的孔道结构,大孔形状表现出六边形结构,产生良好的开放性,较大的比表面积和孔容积为传质提供了较大的空间。非金属C和稀土金属Nd通过相互协同作用,使多级有序C/Nd/TiO_(2)的禁带宽度变窄,从而表现出良好的光催化活性,在光照210 min时,其光催化脱色率可达81.15%。

可见光波段高温标定的简化方法

为了提高可见光波段(0.3μm~0.9μm)高温标定的效率,提出了可见光波段高温标定的简化方法。本文提出了带有曝光时间变量的可见光波段的高温标定模型,通过大量实验发现,RGB相机各个通道的灰度值不仅随曝光时间递增呈线性变化,且随黑体辐射亮度的递增也呈线性变化,进而确定了可见光波段高温标定模型的具体形式。为了求解简化后的可见光波段高温标定模型中的未知数,在两个黑体辐射亮度下,分别采集两个曝光时间下的图像数据,接着,对图像数据进行处理,便可以得到任意曝光时间下的RGB相机高温标定曲线。最后,对本文提出的简化可见光波段高温标定方法与常规按曝光时间进行可见光波段高温标定法进行比较。实验结果表明:R、G、B通道计算值与标定值的相对误差最大值分别为3.38%、2.56%和−1.14%,且各通道的计算值与标定值的相对误差均未超过3.50%。本文提出的数学模型可以有效地简化传统的高温标定法,进而大大缩短了高温标定时间,提高了高温标定的标定效率。

基于线性规划的光谱响应函数反演方法初探

光谱响应函数是卫星遥感器中各个光学元件的反射和透射特性的体现。由于遥感器发射前在地面实验室通过光谱校准获得的光谱响应函数是不准确的,而且在太空中运行的过程中,光谱响应函数可能会以未知的方式发生退化。这两种现象都会对卫星辐射定标工作的精确性产生严重影响。本文针对可见光波段,提出了一种基于线性规划的光谱响应函数反演方法,该方法具有良好的全局收敛性,不依赖于光谱响应函数初值。通过模拟的大气顶高光谱反射率数据和对应通道的卫星反射率数据可以反演得到真实状态下的光谱响应函数。在光谱响应函数的反演过程中具有有效的定性和定量性能,反演得到的光谱响应函数满足应用需求。

Ge/ZnSe一维光子晶体设计及其可见/红外反射光谱调控

光子晶体因其光学隐身方面的潜在应用引起了人们极大的研究兴趣,但是在实际研究上,较少涉及到可见光与红外波段兼容的隐身结构。设计了Ge/ZnSe光子晶体在可见光(0.4~0.8μm)、中红外(3~5μm)与远红外(8~14μm)三个波段兼容隐身的光子晶体结构。首先,通过调制光子晶体的膜层厚度与周期数,得到了在中红外(3~5μm)波段平均反射率可达到83.63%的Ge/ZnSe光子晶体,并且在远红外(8~14μm)波段该光子晶体平均反射率也达到83.2%,表明其具有优良的中远红外光谱高反射率特性。之后,通过在光子晶体结构最上层添加MgF 2薄膜,可以使可见光反射率降低到20%,从而实现可见光高透明度、低可视度的效果。另一方面,也可以在光子晶体最上层添加MgF 2/Ge光子晶体结构,使可见光反射率增加到70.1%,从而抑制光照条件下材料对太阳光能量的吸收,抑制温度升高,辅助降低红外辐射特性。

纳米材料显现潜在手印的研究进展

手印显现技术经过近百年的发展,已经能够对犯罪现场大多数潜在手印进行显现。但随着社会的发展和犯罪手段的更新,各种潜在手印的显现也对现有技术和材料提出了挑战。纳米材料因其拥有良好的吸附性、不容易漂浮于空中、适用性广和一般不影响DNA检验等优势,在显现潜在手印方面已获得了广泛关注。本文综述了各种新型纳米材料在潜在手印显现中的应用研究现状,重点阐述了金属纳米材料、非金属纳米材料、金属氧化物纳米材料以及其他纳米材料在潜在手印显现中的应用研究,并展望了纳米材料显现潜在手印技术的发展趋势,以期为进一步推进纳米材料显现潜在手印的实战应用提供参考。

内镜检查对声带白斑病理诊断的预测价值研究

目的旨在确定内镜下白光成像(white lighting imaging,WLI)和窄带成像(narrow band imaging,NBI)对声带白斑(vocal cord leukoplakia,VCL)病理类型进行诊断的最佳截断点,以提高非侵入性预测VCL病理性质的准确性,并为VCL患者是否需要手术干预及手术时机提供参考依据。方法纳入96例确诊病理性质为VCL患者。术前分别进行WLI模式及NBI模式下的图像采集,并对病变进行WLI模式Chen分型和NBI模式Ni分型的评定。通过比较受试者操作特征曲线的约登指数得出分型的最佳截断值。通过比较2种临床分型的曲线下面积(area under the curve,AUC)、最佳截断值下的准确度、敏感度、特异性、阳性预测值及阴性预测值评价不同临床分型对VCL病理性质的诊断效能。结果WLI模式Chen分型、NBI模式Ni分型与病理等级间均存在相关性(rs=0.513、0.653,P<0.001)。WLI模式Chen分型的最佳截断值为3,即光滑平坦型及光滑隆起型为良性病变,粗糙型为恶性病变;NBI模式Ni分型的最佳截断值为5,即Ⅰ~Ⅳ型为良性病变,Ⅴ型、Ⅵ型为恶性病变。WLI模式Chen分型、NBI模式Ni分型的AUC分别为0.815,0.875。最佳截断值的准确度、敏感度、特异性、阳性预测值及阴性预测值Chen分型为79.51%,84.62%,75.71%,72.13%,86.89%;Ni分型为85.25%,76.92%,91.42%,86.96%,84.21%。结论NBI模式Ni分型及WLI模式Chen分型的诊断效能均较高,但NBI模式Ni分型对VCL病理性质的诊断效能高于白光模式Chen分型。

杭州地铁1号线计轴红光带问题分析及解决方案

[目的]在杭州地铁1号线三期区段动车调试及试运行过程中,在线路不同位置处,计轴设备均出现了受扰异常占用(红光带)的情况,严重影响了地铁的运营安全。因此,有必要对异常受扰场景进行分析和测试试验,选择合适的改进方案解决计轴设备的受扰异常占用问题。[方法]介绍了列车通过1号线三期计轴区段异常受扰占用情况;分析了列车牵引设备回流与计轴设备干扰谐波之间的关系,并进行了相关调查测试及验证;提出了列车牵引设备与计轴设备工作频段重叠产生干扰谐波的解决方案。[结果及结论]对于1号线三期工程列车通过三期计轴区段异常受扰占用(红光带)情况,可采用优化列车牵引系统设备工作频率参数的方法解决该问题,错开列车牵引设备工作频段与计轴设备工作频段,以解决设备的同频干扰问题。

铁路光带覆盖理论与实践探析

为明确铁路覆盖效果测算的基本原理和判定标准,提升测算质量和效率,对铁路光带覆盖理论与实践问题进行研究。在介绍铁路覆盖测算的基础上,阐述铁路光带覆盖理论基本概念,提出运用光带覆盖理论进行覆盖测算的主要流程,包括选定测算线路、生成覆盖光带、指定覆盖对象、覆盖效果测算等步骤,研究光带生成理论、权威统计口径、合理覆盖对象等问题,并提出路网覆盖行政区测算、路网覆盖经济社会发展指标测算、规划项目必要性分析、关键节点覆盖测算4个光带覆盖理论的主要应用方向。结合地理信息技术,提出基于缓冲区的铁路光带覆盖信息化自动测算方法,分析了GIS二次开发的基本算法流程和关键技术。实践证明,光带覆盖理论能够准确高效地实现高速铁路覆盖效果测算,已成为我国铁路覆盖评价的主要方法,相关思路可为基础设施覆盖效果评价提供参考。

慢性胃炎Hp感染患者白光内镜、窄带成像、京都胃炎评分的检查结果分析

目的:分析慢性胃炎幽门螺杆菌(Helicobacter pylori,Hp)感染患者白光内镜、窄带成像、京都胃炎评分的检查结果。方法:回顾性分析2021年1月—2023年8月于宜春学院第二附属医院就诊的84例慢性胃炎患者的临床资料,根据患者是否发生Hp感染进行分组,其中59例感染Hp患者纳入感染组,其余25例纳入未感染组。比较两组白光胃镜下胃黏膜改变情况(萎缩、弥漫性发红、肠上皮化生、增生性息肉、黄色素瘤、鸡皮样改变、皱襞肿大、蛇形),窄带成像下胃小凹形态分布(A、B、C、D、E型)及集合静脉形态分布(R、I、D型),比较两组京都胃炎评分。结果:白光内镜下,感染组萎缩、肠上皮化生、增生性息肉、黄色素瘤、皱襞肿大、蛇形占比均显著高于未感染组,差异均有统计学意义(P<0.05);两组弥漫性发红、鸡皮样改变占比比较,差异均无统计学意义(P>0.05);感染组胃小凹A、B、C型占比均显著低于未感染组,D、E型比例均显著高于未感染组,差异均有统计学意义(P<0.05);感染组集合静脉形态分布I型和D型占比均显著高于未感染组,差异均有统计学意义(P<0.05);感染组京都胃炎评分中的鸡皮样改变、弥漫性发红、萎缩、肠上皮化生、皱襞肿大评分均显著高于未感染组(P<0.05)。结论:Hp感染的慢性胃炎患者采用白光内镜、窄带成像、京都胃炎评分检查后,其结果均与未感染Hp的慢性胃炎患者有异,通过上述检测方式对慢性胃炎患者的病理状态情况进行观察,可作为临床上检测Hp感染的辅助手段之一。