In_（0．2）Ga_（0．8）As／GaAs应变多量子阱结构的光调制反射和热调制反射谱的研究

对Ｉｎ（０．２）Ｇａ（０．８）Ａｓ／ＧａＡｓ应变多量子阱在７７Ｋ下的光调制反射谱（ＰＲ）和热调制反射谱（ＴＲ）进行了实验研究．对ＰＲ结果的线形拟合指认了应变多量子阱中子能级的跃迁，并与理论计算结果作了比较．实验对比确认ＰＲ中１１Ｈ、１３Ｈ等跃迁结构为非耦合态、具有电场调制机构的一阶微商性质．而１１Ｌ、３１Ｈ、２２Ｈ等跃迁结构为阶间耦合态，对这些隧穿耦合的低场调制产生三阶微商特性．     

Infrared Radiance Simulation and Application under Cloudy Sky Conditions Based on HIRTM

An algorithm based on hyperspectral infrared cloudy radiative transfer model (HIRTM) is introduced and a simulation method for infrared image of the generation geostationary meteorological satellite is proposed. Based on the parameters from weather research and forecast (WRF), such as the water content, atmospheric temperature, and humidity profile, the simulation data for the advanced Himawari imager (AHI) infrared radiative (IR) channels of Himawari-8 are obtained. Simulated results based on HIRTM agree well with the observed data. Further, the movement, development, and change of the cloud are well predicated. And the simulation of IR cloud image for the weather forecast has been obtained. This paper provides an improved method for evaluation and improvement of regional numerical model for weather forecast.     

基于本征音子说话人子空间的说话人自适应算法

本征音子说话人自适应算法在自适应数据量充足时可以取得很好的自适应效果,但在自适应数据量不足时会出现严重的过拟合现象。为此该文提出一种基于本征音子说话人子空间的说话人自适应算法来克服这一问题。首先给出基于隐马尔可夫模型-高斯混合模型(HMM-GMM)的语音识别系统中本征音子说话人自适应的基本原理。其次通过引入说话人子空间对不同说话人的本征音子矩阵间的相关性信息进行建模;然后通过估计说话人相关坐标矢量得到一种新的本征音子说话人子空间自适应算法。最后将本征音子说话人子空间自适应算法与传统说话人子空间自适应算法进行了对比。基于微软语料库的汉语连续语音识别实验表明,与本征音子说话人自适应算法相比,该算法在自适应数据量极少时能大幅提升性能,较好地克服过拟合现象。与本征音自适应算法相比,该算法以较小的性能牺牲代价获得了更低的空间复杂度而更具实用性。     

The First Flexible Dual‐Ion Microbattery Demonstrates Superior Capacity and Ultrahigh Energy Density: Small and Powerful

Humans live today in a high‐tech and informationalized society. With the development of the emerging electronic information age, various electronic systems are inclined to be multifunctional and miniaturized. It is urgent to develop “small and powerful” micro‐batteries with flexibility and high electrochemical performance to meet the diverse needs of microelectronic components. However, low electrochemical performance exists in traditional microenergy storage devices, which fail to satisfy the energy needs for microdevices. Here, for the first time, a planar integrated flexible rechargeable dual‐ion microbattery (DIMB) is reported, which is fabricated from an interdigital pattern of graphite as an electrode and lithium hexafluorophosphate as an electrolyte. As a microbattery, the DIMB exhibits a high reversible capacity of 56.50 mAh cm^?3, and excellent cycle stability with 90% capacity retention after 300 cycles under a high working voltage. The application of DIMB in microdevices, such as light‐emitting diodes (LEDs), digital electronic game consoles, and electrochromic glasses is also investigated, fully demonstrating its “small and powerful” performance. The integrated DIMB is a high‐voltage microdevice that reaches a nonpareil discharge voltage of about 100 V and a charging capacity of 102 mAh g^?1. This dual ion‐based flexible microbattery could become a promising candidate for energy storage and conversion components in next‐generation microelectronic devices and integrated electronic devices.     

Transcatheter Self‐Powered Ultrasensitive Endocardial Pressure Sensor

Changes in endocardial pressure (EP) have important clinical significance for heart failure patients with impaired cardiac function. As a vital parameter for evaluating cardiac function, EP is commonly monitored by invasive and expensive cardiac catheterization, which is not feasible for long‐term and continuous data collection. In this work, a miniaturized, flexible, and self‐powered endocardial pressure sensor (SEPS) based on triboelectric nanogenerator (TENG), which is integrated with a surgical catheter for minimally invasive implantation, is reported. In a porcine model, SEPS is implanted into the left ventricle and the left atrium. The SEPS has a good response both in low‐ and high‐pressure environments. The SEPS achieves the ultrasensitivity, real‐time monitoring, and mechanical stability in vivo. An excellent linearity (R ² = 0.997) with a sensitivity of 1.195 mV mmHg^?1 is obtained. Furthermore, cardiac arrhythmias such as ventricular fibrillation and ventricular premature contraction can also be detected by SEPS. The device may promote the development of miniature implantable medical sensors for monitoring and diagnosis of cardiovascular diseases.     

传输腔稳频的397nm半导体激光器

商用的半导体激光器由于其长期漂移大,不能满足单离子光频标中离子的激光冷却和长时间探测的目的。因此,采用了传输腔稳频技术减小商用397nm半导体激光器的长期漂移。利用经过Pound-Drever-Hall(PDH)技术锁定的729nm超稳激光器作参考激光,采用扫描的法布里-珀罗(F-P)干涉仪作传输介质,实现了397nm半导体激光器的长稳锁定。稳频后397nm激光器在1h内的漂移小于1MHz,100s的Allan方差小于1×10-10。这些指标为下一步利用传输腔技术实现866nm激光的长稳锁定打下了基础,同时为优化单个钙离子的激光冷却和长时间精密测量提供了条件。     

Ti中间层对超薄Ni膜硅化反应特性的影响

在多种Si衬底上利用离子束溅射淀积超薄Ni膜以及Ni/Ti双层膜,经过快速热退火处理完成薄膜的固相硅化反应,通过四探针法、微区喇曼散射法和俄歇深度分布测试法研究了Ti中间层对Ni硅化反应的影响.实验结果证明Ti中间层抑制了集成电路生产最需要的NiSi相的形成.     

圆形台面中的AlAs/AlGaAs湿法氧化动力学规律

AlAs/AlGaAs湿法氧化技术是制备氧化物限制型VCSELs工艺中极为重要的一步,形成的氧化孔会直接影响到器件的各个特性参数,故有必要对氧化动力学规律进行深入地研究.首先根据大量氧化实验得到了一般氧化规律曲线,再通过结合一维Deal-Grove氧化动力学模型,对比一维条形、二维圆形凸、凹台面的氧化规律,推导出了简单实用的二维圆形台面的氧化模型,所得模型曲线与实验数据均吻合较好,并成功地运用此模型实现了对氧化孔大小的精确控制.     

Tuning the Poisson's Ratio of Biomaterials for Investigating Cellular Response

Cells sense and respond to mechanical forces, regardless of whether the source is from a normal tissue matrix, an adjacent cell or a synthetic substrate. In recent years, cell response to surface rigidity has been extensively studied by modulating the elastic modulus of poly(ethylene glycol) (PEG)‐based hydrogels. In the context of biomaterials, Poisson's ratio, another fundamental material property parameter has not been explored, primarily because of challenges involved in tuning the Poisson's ratio in biological scaffolds. Two‐photon polymerization is used to fabricate suspended web structures that exhibit positive and negative Poisson's ratio (NPR), based on analytical models. NPR webs demonstrate biaxial expansion/compression behavior, as one or multiple cells apply local forces and move the structures. Unusual cell division on NPR structures is also demonstrated. This methodology can be used to tune the Poisson's ratio of several photocurable biomaterials and could have potential implications in the field of mechanobiology.