1 无锡学院江苏省集成电路可靠性技术及检测系统工程研究中心，江苏 无锡 214105
2 中国科学院长春光学精密机械与物理研究所，吉林 长春 130033
为了探究铟原子发生自适应迁移的临界厚度，首先测量得到InGaAs阱簇复合结构表面不同位置的自发辐射光谱。铟原子的自适应迁移会导致阱簇复合结构中同时产生铟含量正常的和损失的InxGa1-xAs区域，进而导致其自发辐射光谱具有特殊的双峰特征。通过对比光谱的双峰强度，计算并评估了正常In0.17Ga0.83As层的厚度起伏为4.6~6.4 nm，即铟原子发生自适应迁移的临界厚度为4.6 nm。通过对比4 nm传统InGaAs量子阱的单峰光谱特征，验证了铟原子发生自适应迁移临界厚度的准确性，该项研究对推动InGaAs阱簇复合量子限制结构的发展具有重要意义。
激光器 InGaAs/GaAs 富铟团簇 双峰光谱 临界厚度 光学学报
2023, 43(21): 2114001
Author Affiliations
Abstract
School of Materials Science and Engineering, Liaocheng University, Liaocheng 252059, P. R. China
Considering the advantages of high Curie temperature and environment-friendly nature of KNN piezoelectric ceramics, the limitation of weak piezoelectric response and their temperature sensitivity to applications is worth exploring. Herein, the <001> textured (1-)(KNa)(NbSb)O3-(BiNa)HfO3( = 0.01−0.045) lead-free ceramics were synthesized by templated grain-growth method. The high piezoelectric performance (d of 474 pC/N and strain of 0.21%) and excellent temperature stability (unipolar strain maintained within 4.3% change between 30C and 165C) were simultaneously achieved in the textured KNNS-0.03BNH ceramics. The high piezoelectric performance can be attributed to the summation of the crystallographic anisotropy and phase structure contributions in <001> textured ceramics. The superior temperature stability of piezoelectric properties can be interpreted by the contribution of crystal anisotropy to piezoelectric properties reduces the effect of phase transition on piezoelectric properties deterioration. This study provides an effective strategy for simultaneously achieving high piezoelectric properties and superior temperature stability in KNN-based textured ceramics.Considering the advantages of high Curie temperature and environment-friendly nature of KNN piezoelectric ceramics, the limitation of weak piezoelectric response and their temperature sensitivity to applications is worth exploring. Herein, the <001> textured (1-)(KNa)(NbSb)O3-(BiNa)HfO3( = 0.01−0.045) lead-free ceramics were synthesized by templated grain-growth method. The high piezoelectric performance (d of 474 pC/N and strain of 0.21%) and excellent temperature stability (unipolar strain maintained within 4.3% change between 30C and 165C) were simultaneously achieved in the textured KNNS-0.03BNH ceramics. The high piezoelectric performance can be attributed to the summation of the crystallographic anisotropy and phase structure contributions in <001> textured ceramics. The superior temperature stability of piezoelectric properties can be interpreted by the contribution of crystal anisotropy to piezoelectric properties reduces the effect of phase transition on piezoelectric properties deterioration. This study provides an effective strategy for simultaneously achieving high piezoelectric properties and superior temperature stability in KNN-based textured ceramics.
Textured ceramics phase structure piezoelectric properties temperature stability Journal of Advanced Dielectrics
2022, 12(5): 2244006
1 先进土木工程材料教育部重点实验室，上海 201804
2 同济大学材料科学与工程学院，上海 201804
采用量热仪、X射线衍射仪、热重、扫描电镜、电感耦合等离子光谱等方法研究了苯丙共聚物(SA)对硫铝酸钙胶结料-无水石膏复合体系早期水化的影响。结果表明：SA会延缓水化进程，减少水化加速期钙矾石(AFt)、单硫型水化硫铝酸钙(AFm)和Al(OH)3 (AH3)含量，促进AH3与石膏和氢氧化钙反应生成AFt，并促进水化后期AFt向AFm转变。同时，SA会迅速降低体系孔溶液的表面张力，随着水化反应进行表面张力趋于稳定；SA也提高了孔溶液的pH值，增大OH-浓度，影响了体系中Ca2+、SO42-QUOTE和［Al(OH)4］-的浓度和比例，减小水化初期水化产物的离子浓度积，降低水化产物析出速率，进而延缓水化进程、减少水化产物。
苯丙共聚物 硫铝酸钙 无水石膏 水化 styrene-acrylic copolymer calcium sulphoaluminate anhydrite hydration
Author Affiliations
Abstract
State Key Laboratory of Bioelectronics, School of Biological Sciences & Medical Engineering, Southeast University, Nanjing 210096, China
Interface emission from heterojunction is a shortcoming for electroluminescent devices. A buffer layer introduced in the heterojunctional interfaces is a potential solution for the challenge. However, the dynamics for carrier tunneling to control the interface emission is still a mystery. Herein, the low-refractive HfO2 with a proper energy band configuration is employed as the buffer layer in achieving ZnO-microwire/HfO2/GaN heterojunctional light-emitting diodes (LEDs). The optically pumped lasing threshold and lifetime of the ZnO microwire are reduced with the introduced HfO2 layer. As a result, the interface emission is of blue-shift from visible wavelengths to 394 nm whereas the ultraviolet (UV) emission is enhanced. To regulate the interface recombination between electrons in the conduction band of ZnO and holes in the valence band of GaN, the tunneling electrons with higher conduction band are employed to produce a higher tunneling current through regulation of thin HfO2 film causing blue shift and interface emission enhancement. Our results provide a method to control the tunneling electrons in heterojunction for high-performance LEDs.
tunneling electron light-emitting diode heterojunctional interface nano HfO2 buffer Opto-Electronic Advances
2021, 4(9): 09200064
1 兰州理工大学理学院, 甘肃 兰州 730050
2 兰州城市学院电子与信息工程学院, 甘肃 兰州 730070
设计了一种基于介质光栅金属薄膜复合结构的折射率传感器。利用He-Ne激光器输出的632.8 nm横磁偏振光激发复合结构中的表面等离子体,得到了高灵敏度的折射率传感器。运用有限元方法,数值模拟了具有不同光栅厚度、周期以及折射率的分析物的反射光谱。对占空比为0.5、金属薄膜厚度为45 nm的复合结构进行了参数优化,得到最优参数为:光栅厚度100 nm、光栅周期500 nm。在最优参数条件下,计算了金属薄膜与具有不同折射率的分析物之间的界面共振角的变化,得到了高达500 (°)/RIU的角灵敏度。该折射率传感器操作简单、成本低、角灵敏度高,具有很好的应用前景。
表面光学 介质光栅/金属薄膜 表面等离子体 折射率 光学学报
2017, 37(11): 1124001
深圳大学 光电工程学院 光电子器件与系统教育部/广东省重点实验室, 深圳 518060
光锥阵列耦合数字X射线探测器是获得大面积高分辨率数字X射线成像的重要途径, 但目前通常采用粘结固定的方式实现光锥阵列各小端面与对应图像传感器芯片之间的耦合.为克服粘结耦合方式的不足, 设计并实现了一种可微调的非粘结2×2光锥阵列耦合数字X射线探测器.该方案能够在调节空间受光锥阵列结构和硬件电路板尺寸限制, 特别是竖直方向板间距离仅40mm的情况下, 通过独特设计的水平和竖直调节机构在同一个调节层上对四块数据采集板分别进行多维度调节.利用四块数据采集板与数据传输板相互分立的特点, 设计了基于ARM+ 4 FPGA的嵌入式以太网多CMOS芯片传输数据采集系统, 所实现的X射线探测器成像面积达100mm×100mm, 能够完成可微调的非粘结耦合和多CMOS芯片的图像数据采集.
X射线探测器 光锥阵列 耦合 X射线成像 调节机构 数据采集 数据传输 X-ray detector Fiber optic taper array Coupling X-ray imaging Adjusting mechanism Data acquisition Data transimission
1 浙江大学, 浙江 杭州310058
2 杭州市第一人民医院, 浙江 杭州310006
对31例结直肠癌患者、 8例肠炎患者和10例健康者的血清冻干粉标本进行傅里叶变换红外光谱(fourier transformation infrared spectrum, FTIR)检测, 对比分析各组红外光谱特征。 结果显示, FTIR检测血清冻干粉获得11个吸收峰, 结直肠癌组P9峰位波数蓝移(1 249 cm-1), 差异有统计学意义(Z=－2.051, p<0.05); 5个吸光度比值组间差异无统计学意义; 层序聚类分析法(hierarchical cluster analysis, HCA)显示结直肠癌个体红外光谱具有一定程度的聚类特性; 对酰胺Ⅰ带光谱(1 700～1 600 cm-1)进行傅里叶解卷积等处理获得蛋白二级结构的百分含量, 组间差异无统计学意义。 研究结果初步提供了血清FTIR光谱用于结直肠癌早期诊断的理论依据。
傅里叶变换红外光谱 结直肠癌 血清 层序聚类分析法 二级结构 FTIR Colorectal cancer Serum HCA Secondary structure
1 安徽华东光电技术研究所 国家特种显示工程中心，安徽 芜湖241002
2 合肥工业大学 计算机学院，安徽 合肥230009
3 安徽工业大学 电气信息学院，安徽 马鞍山243000
飞机中液晶显示屏上显示的一般是图形和数据，显示界面上有较大范围是暗场景。若采用传统液晶显示器恒定亮度的面光源，会造成不必要的电能消耗，且存在漏光现象导致图像的对比度下降，因此对液晶显示的背光源采用动态背光的控制。文章通过分析常见的平均值和最大值背光亮度提取方法，提出基于灰阶熵的LCD背光亮度调整方法。该方法既解决平均值法失真严重的问题，保证图像质量，同时相比于最大值法又减少功耗，达到降低功耗和保证图像质量的要求。
液晶显示器 动态背光 灰阶熵 liquid crystal display dynamic backlight gray entropy
