Properties of a CdZnO/ZnO Multiple Quantum-Well Light-Emitting Diode

Zhan-Hui Liu,Li-Li Zhang,Qing-Fang Li,Rong Zhang,Zi-Li Xie,Xiang-Qian Xiu,Bin Liu 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.69 No.7

A CdZnO/ZnO multiple quantum-well light-emitting diode (LED) structure was successfully grown by using plasma-assisted molecular beam epitaxy on a p-GaN template that had been grown by using metal-organic chemical-vapor deposition on a c-sapphire substrate. The properties of the sample were characterized by using high-resolution X-ray diffraction, transmission electron microscopy, and temperature-dependent photoluminescence measurements. The light output performance of the CdZnO/ZnO QW LED device was also investigated in detail by using I-V and electroluminescence spectral measurements. The characterization showed that our CdZnO/ZnO QW LED structure had good crystalline quality and weaker carrier localization. Owing to the heterojunction structure, the I-V curve indicated that the LED device had a higher turn-on voltage and series resistance. The EL measurement demonstrated that for our LED device’s optoelectronic characteristic, the carrier-screening effect played the dominant role in the emission-energy blue-shift mechanism, and the broadening of the emission energy width was mainly ascribed to the band-filling effect. Without a special heat sinking, the L-I curve exhibited slight efficiency droop after 30 mA.

Expression HpaG(Xooc) Protein in Bacillus subtilis and its Biological Functions

( Hui Jun Wu ),( Shuai Wang ),( Jun Qing Qiao ),( Jun Liu ),( Jiang Zhan ),( Xue Wen Gao ) 한국미생물 · 생명공학회 2009 Journal of microbiology and biotechnology Vol.19 No.2

Hyperparameters optimization of convolutional neural network based on local autonomous competition harmony search algorithm

Liu Dongmei,Ouyang Haibin,Li Steven,장춘량,Zhan Zhi-Hui 한국CDE학회 2023 Journal of computational design and engineering Vol.10 No.4

Because of the good performance of convolutional neural network (CNN), it has been extensively used in many fields, such as image, speech, text, etc. However, it is easily affected by hyperparameters. How to effectively configure hyperparameters at a reasonable time to improve the performance of CNNs has always been a complex problem. To solve this problem, this paper proposes a method to automatically optimize CNN hyperparameters based on the local autonomous competitive harmony search (LACHS) algorithm. To avoid the influence of complicated parameter adjustment of LACHS algorithm on its performance, a parameter dynamic adjustment strategy is adopted, which makes the pitch adjustment probability PAR and step factor BW dynamically adjust according to the actual situation. To strengthen the fine search of neighborhood space and reduce the possibility of falling into local optima for a long time, an autonomous decision-making search strategy based on the optimal state is designed. To help the algorithm jump out of the local fitting situation, this paper proposes a local competition mechanism to make the new sound competes with the worst harmonic progression of local selection. In addition, an evaluation function is proposed, which integrates the training times and recognition accuracy. To achieve the purpose of saving the calculation cost without affecting the search result, it makes the training time for each model depending on the learning rate and batch size. In order to prove the feasibility of LACHS algorithm in configuring CNN superparameters, the classification of the Fashion-MNIST dataset and CIFAR10 dataset is tested. The comparison is made between CNN based on empirical configuration and CNN based on classical algorithms to optimize hyperparameters automatically. The results show that the performance of CNN based on the LACHS algorithm has been improved effectively, so this algorithm has certain advantages in hyperparametric optimization. In addition, this paper applies the LACHS algorithm to expression recognition. Experiments show that the performance of CNN optimized based on the LACHS algorithm is better than that of the same type of artificially designed CNN. Therefore, the method proposed in this paper is feasible in practical application.

In-plane vibration analysis of cantilevered circular arc beams undergoing rotational motion

Guang Hui Zhang,Zhan Sheng Liu,Hong Hee Yoo 대한기계학회 2008 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.22 No.1

Equations of motion of cantilevered circular arc beams undergoing rotational motion are derived based on a dynamic modeling method developed in this paper. Kane’s method is employed to derive the equations of motion. Different from the classical linear modeling method which employs two cylindrical deformation variables, the present modeling method employs a non-cylindrical variable along with a cylindrical variable to describe the elastic deformation. The derived equations (governing the stretching and the bending motions) are coupled but linear, so they can be directly used for vibration analysis. The coupling effect between the stretching and the bending motions, which could not be considered in the conventional modeling method, is considered in this modeling method. The effects of rotational speed, arc angle, and hub radius ratio on the natural frequencies of the rotating circular arc beam are investigated through numerical analysis.

Gain tuning method of closed-loopinjection low-order feedforward controller considering axis dynamics

Chengpeng Zhan,Lei Yang,Hui Liu,Huijie Zhang,Wanhua Zhao,Yaolong Chen 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.10

Low-order feedforward controllers have attracted much attention in engineering applications due to their simple structure and easy implementation. This paper focuses on loworder feedforward controllers with closed-loop-injection architectures. Currently, the gain of this type of feedforward controller is tuned with the goal of accurately fitting the following error. However, due to the limited control bandwidth, the compensation signal generated by the feedforward controller cannot be fully responded to by the feed axis. This paper proposes a new gain-tuning method. It enhances the feedforward controller's performance by considering the axis dynamics. The effectiveness of the proposed method is verified by experiments implemented on a two-axis bench. The results show that, compared with the method that does not consider the axis dynamics, the proposed method further reduces the following error and the trajectory error during trajectory tracking.

In-plane Vibration Analysis of Rotating Cantilever Curved Beams

Guang Hui Zhang,Zhan Sheng Liu,Hong Hee Yoo 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5

Equations of motion of rotating cantilever curved beams are derived based on a dynamic modeling method developed in this paper. The Kane’s method is employed to derive the equations of motion. Different from the classical linear modeling method which employs two cylindrical deformation variables, the present modeling method employs a non-cylindrical variable along with a cylindrical variable to describe the elastic deformation. The derived equations (governing the stretching and the bending motions) are coupled but linear. So they can be directly used for the vibration analysis. The coupling effect between the stretching and the bending motions which could not be considered in the conventional modeling method is considered in this modeling method. The natural frequencies of the rotating curved beams versus the rotating speed are calculated for various radii of curvature and hub radius ratios.

Gamma and X-ray irradiation as a phytosanitary treatment against various stages of Planococcus lilacinus (Hemiptera: Pseudococcidae)

Ma Chen,Liu Hui,Liu Bo,Zhao Ju-Peng,Zhao Qing-Ying,Song Zi-Jiao,Han Xin,Zhan Guo-Ping 한국응용곤충학회 2022 Journal of Asia-Pacific Entomology Vol.25 No.4

The cacao mealybug, Planococcus lilacinus Cock, is an important quarantine pest. Infested commodity should be subject to appropriate phytosanitary treatment, while irradiation is recommended for the cacao mealybug. Radio-tolerance comparison tests were conducted on the crawler, nymphs, and adult females of P. lilacinus at the X-ray radiation doses of 40, 80, and 120 Gy, respectively. The results showed that irradiation had a strong effect on preventing of development and reproduction; the adult female stage was identified as the most tolerant. During the following dose–response tests, among young and late females X-ray-irradiation (20–100 Gy), the late females were most tolerant when preventing F 1 generation 2nd instars emergence was used as the evaluation criterion. Minimum absorbed dose and its 95 % fiducial limits to provide probit 9 efficacy at 95 % confidence level (100 % mortality/inhibition in an estimated population of 93,616 individuals) were 131.5 Gy (122.5, 142.6 Gy) and 144.4 Gy (132.7, 159.4 Gy), estimating from the probit analysis on dose-mortality data of 1–30 and 1–10-day-old neonates laid by late females, respectively. In the large-scale confirmatory tests, a total of estimating 97,384 late females of P. lilacinus rearing on the pumpkins fruits were irradiated with gamma-ray at the target dose of 135 or 145 Gy (measured doses 126.1–163.0 Gy), which resulted in no F 1 generation 2nd nymphs developing during a 6-week post-treatment period. The treatment efficacy calculated is 99.9969 % at the 95 % confidence level. Therefore, a minimum absorbed dose of 163.0 Gy is recommended for phytosanitary treatment of P. lilacinus in infested commodity.

Properties of an AlGaN/AlN Distributed-Bragg-reflector Structure

Li-Li Zhang,Zhan-Hui Liu,Xiao-Gu Huang,Qing-Fang Li,Rong Zhang,Zi-Li Xie,Xiang-Qian Xiu 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.7

An AlGaN/AlN distributed-Bragg-reflector (DBR) structure with a high Al content was grown byusing plasma-assisted molecular beam epitaxy (PA-MBE). The properties of the sample were characterizedby using the transmission electron microscopy, high-resolution X-ray diffraction, atomicforce microscopy, and reflectivity spectrum measurements. The reciprocal space mapping analysisindicated that the strain in the AlGaN layers was partially relaxed. The morphology of the DBRexhibited a surface covered by grains (average size of about 130 nm), and the surface roughness wasabout 2 nm. The spectral measurements showed that the DBR structure presented a peak reflectivityof 68.8% at the center wavelength of 247 nm, which indicated that this DBR structure couldwork in the deep solar-blind UV region with acceptable reflectivity. However, the optical propertiesof the DBR structure were deteriorated by the fluctuation of the Al composition, non-uniformity ofthe layer thickness, the blurry, rough interface in the DBR structure, and so on.

Gingerol Inhibits Cisplatin-induced Vomiting by Down Regulating 5-Hydroxytryptamine, Dopamine and Substance P Expression in Minks

Qiu-hai Qian,Wen-hui Chen,Wang Yue,Yao-xia Wang,Zhi-hong Yang,Zhan-tao Liu 대한약학회 2009 Archives of Pharmacal Research Vol.32 No.4

Objective: To investigate the antiemetic effect of gingerol and its multi-targets effective mechanism on 5-hydroxytryptamine (5-HT), dopamine (DA) and substance P (SP). The antiemetic effect of gingerol was investigated on a vomiting model of mink induced by cisplatin (7.5 mg· kg−1, i.p.) in 6 h observation. The levels of 5-HT, DA and distribution of substance P in the area postrema and ileum were measured by high performance liquid chromatography (HPLC) and immunohistochemistry respectively. The frequency of cisplatin induced retching and vomiting was significantly reduced by pretreatment with gingerol in a dose-dependent manner (P<0.05). Cisplatin produced a significant increase in 5-HT and DA levels in the area postrema and ileum of minks (P<0.05), and this increase was significantly inhibited by gingerol in a dose-dependent manner (P<0.05). Substance P-immunoreactive was mainly situated in the mucosa and submucosa of ileum as well as in the neurons of area postrema, and gingerol markedly suppressed the increase immunoreactivity of substance P induced by cisplatin in a dose-dependent manner (P<0.05). Gingerol has good activity against cisplatin-induced emesis in minks possibly by inhibiting central or peripheral increase of 5-HT, DA and substance P.

Targeting EGFL7 Expression through RNA Interference Suppresses Renal Cell Carcinoma Growth by Inhibiting Angiogenesis

Xu, Han-Feng,Chen, Lei,Liu, Xian-Dong,Zhan, Yun-Hong,Zhang, Hui-Hui,Li, Qing,Wu, Bin Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.7

Renal cell carcinoma (RCC) is the most lethal of all urological cancers and tumor angiogenesis is closely related with its growth, invasion, and metastasis. Recent studies have suggested that epidermal growth factor-like domain multiple 7 (EGFL7) is overexpressed by many tumors, such as colorectal cancer and hepatocellular carcinoma; it is also correlated with progression, metastasis, and a poor prognosis. However, the role of EGFL7 in RCC is not clear. In this study, we examined how EGFL7 contributes to the growth of RCC using a co-culture system in vitro and a xenograft model in vivo. Downregulated EGFL7 expression in RCC cells affected the migration and tubule formation of HMEC-1 cells, but not their growth and apoptosis in vitro. The level of focal adhesion kinase (FAK) phosphorylation in HMEC-1 cells decreased significantly when co-cultured with 786-0/iEGFL7 cells compared with 786-0 cells. After adding rhEGFL7, the level of FAK phosphorylation in HMEC-1 cells was significantly elevated compared with phosphate-buffered saline (PBS) control. However, FAK phosphorylation was abrogated by EGFR inhibition. The average size of RCC local tumors in the 786-0/iEGFL7 group was noticeably smaller than those in the 786-0 cell group and their vascular density was also significantly decreased. These data suggest that EGFL7 has an important function in the growth of RCC by facilitating angiogenesis.