Analysis of the Optical Constants of Aluminum-doped Zinc-oxide Films by Using the Single-oscillator Model

Xiao-Yong Gao,Yan Liang,Qing-Geng Lin 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.57 No.4

A group of aluminum-doped zinc-oxide (AZO) films were prepared on glass substrates by directcurrent reactive magnetron sputtering at substrate temperatures (Ts) ranging from 170 ℃ to 210 ℃. The optical constants of the AZO films defined by using Caughy model were fitted in terms of a two-layer model by using the measured spectroscopic ellipsometric parameters. The refractive index dispersion data below the interband absorption edge of the AZO films were analyzed by using a single-oscillator model. The optical energy gap as-fitted by using the single-oscillator model demonstrated a blue and a red shift as T<SUB>s</SUB> increased from 170 ℃ to 200 ℃ and above 200 ℃, respectively. This could be attributed to a change in the free electron concentration, which was related to a change in the effective Al-doping efficiency. The calculated parameter β, related to the crystalline structure, indicated that the as-deposited AZO films fell into an ionic class even though β had a slight deviation from the ionic value. The β of the as-deposited AZO film at 200 ℃ largely remained in the range of ionic values, indicating a minimum deviation from the wurtzite structure. This denoted that Al is a very effective substitute for the zinc sites. Additionally, the calculated plasma frequency, hw<SUB>p</SUB>, remained in the violet region.

Growth Rate and Biomass Productivity of Chlorella as Affected by Culture Depth and Cell Density in an Open Circular Photobioreactor

( Fang Liang ),( Xiao Bin Wen ),( Yahong Geng ),( Zheng Rong Ouyang ),( Li Ming Luo ),( Ye Guang Li ) 한국미생물 · 생명공학회 2013 Journal of microbiology and biotechnology Vol.23 No.4

The effects of culture depth (2-10 cm) and cell density on the growth rate and biomass productivity of Chlorella sp. XQ-200419 were investigated through the use of a selfdesigned open circular pond photobioreactor-imitation system. With increases in culture depths from 2 to 10 cm, the growth rate decreased significantly from 1.08 /d to 0.39 /d. However, the biomass productivity only increased slightly from 8.41 to 11.22 g/m2/d. The biomass productivity (11.08 g/m2/d) achieved in 4 cm culture with an initial OD540 of 0.95 was similar to that achieved in 10 cm culture with an initial OD540 of 0.5. In addition, the duration of maximal areal productivity at a 4 cm depth was prolonged from 1 to 4 days, a finding that was also similar to that of the culture at a 10 cm depth. In both cases, the initial areal biomass densities were identical. Based on these results and previous studies, it can be concluded that the influence of culture depth and cell density on areal biomass productivity is actually due to different areal biomass densities. Under suitable conditions, there are a range of optimal biomass densities, and areal biomass productivity reaches its maximum when the biomass density is within these optimal ranges. Otherwise, biomass productivity will decrease. Therefore, a key factor for high biomass productivity is to maintain an optimal biomass density.

TP53I11 suppresses epithelial-mesenchymal transition and metastasis of breast cancer cells

( Tongqian Xiao ),( Zhongjuan Xu ),( Hai Zhang ),( Junsa Geng ),( Yong Qiao ),( Yu Liang ),( Yanzhen Yu ),( Qun Dong ),( Guangli Suo ) 생화학분자생물학회(구 한국생화학분자생물학회) 2019 BMB Reports Vol.52 No.6

Epithelial-mesenchymal transition (EMT) is widely-considered to be a modulating factor of anoikis and cancer metastasis. We found that, in MDA-MB-231 cells, TP53I11 (tumor protein P53 inducible protein 11) suppressed EMT and migration in vitro, and inhibited metastasis in vivo. Our findings showed that hypoxic treatment upregulated the expression of HIF1α, but reduced TP53I11 protein levels and TP53I11 overexpression reduced HIF1α expression under normal culture and hypoxicconditions, and in xenografts of MDA-MB-231 cells. Considering HIF1α is a master regulator of the hypoxic response and that hypoxia is a crucial trigger of cancer metastasis, our study suggests that TP53I11 may suppress EMT and metastasis by reducing HIF1α protein levels in breast cancer cells. [BMB Reports 2019; 52(6): 379-384]

Guidance Law for Near Space Interceptor based on Block Backstepping Sliding Mode and Extended State Observer

GUO Chao,LIANG Xiao-Geng 한국항공우주학회 2014 International Journal of Aeronautical and Space Sc Vol.15 No.2

This paper proposes a novel guidance law based on the block backstepping sliding mode control and extended state observer (ESO), which also takes into account the autopilot dynamic characteristics of the near space interceptor (NSI), and the impact angle constraint of attacking the maneuvering target . Based on the backstepping control approach, the target maneuvers and the parameter uncertainties of the autopilot are regarded as disturbances of the outer loop and inner loop, respectively. Then, the ESO is constructed to estimate the target acceleration and the inner loop disturbance, and the block backstepping sliding model guidance law is employed, based on the estimated disturbance value. Furthermore, in order to avoid the “explosion of complexity” problem, first-order low-pass filters are also introduced, to obtain differentiations of the virtual control variables. The stability of the closed-loop guidance system is also proven, based on the Lyapunov theory. Finally, simulation results demonstrate that the proposed guidance law can not only overcome the influence of the autopilot dynamic delay and target maneuvers, but also obtain a small miss distance.

Apatinib Combined with Local Irradiation Leads to Systemic Tumor Control via Reversal of Immunosuppressive Tumor Microenvironment in Lung Cancer

Li-jun Liang,Chen-xi Hu,Yi-xuan Wen,Xiao-wei Geng,Ting Chen,Guo-qing Gu,Lei Wang,You-you Xia,Yong Liu,Jia-yan Fei,Jie Dong,Feng-hua Zhao,Yiliyar Ahongjiang,Kai-yuan Hui,Xiao-dong Jiang 대한암학회 2020 Cancer Research and Treatment Vol.52 No.2

Purpose This study aimed to investigate the potential systemic antitumor effects of stereotactic ablative radiotherapy (SABR) and apatinib (a novel vascular endothelial growth factor receptor 2 inhibitor) via reversing the immunosuppressive tumor microenvironment for lung carcinoma. Materials and Methods Lewis lung cancer cells were injected into C57BL/6 mice in the left hindlimb (primary tumor; irradiated) and in the right flank (secondary tumor; nonirradiated). When both tumors grew to the touchable size, mice were randomly divided into eight treatment groups. These groups received normal saline or three distinct doses of apatinib (50 mg/kg, 150 mg/kg, and 200 mg/kg) daily for 7 days, in combination with a single dose of 15 Gy radiotherapy or not to the primary tumor. The further tumor growth/regression of mice were followed and observed. Results For the single 15 Gy modality, tumor growth delay could only be observed at the primary tumor. When combining SABR and apatinib 200 mg/kg, significant retardation of both primary and secondary tumor growth could be observed, indicated an abscopal effect was induced. Mechanism analysis suggested that programmed death-ligand 1 expression increased with SABR was counteract by additional apatinib therapy. Furthermore, when apatinib was combined with SABR, the composition of immune cells could be changed. More importantly, this two-pronged approach evoked tumor antigen–specific immune responses and the mice were resistant to another tumor rechallenge, finally, long-term survival was improved. Conclusion Our results suggested that the tumor microenvironment could be managed with apatinib, which was effective in eliciting an abscopal effect induced by SABR.

Down-regulation of Long Non-coding RNA TUG1 Inhibits Osteosarcoma Cell Proliferation and Promotes Apoptosis

Zhang, Qiang,Geng, Pei-Liang,Yin, Pei,Wang, Xiao-Lin,Jia, Jin-Peng,Yao, Jie Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.4

Objective: To investigate the expression level of TUG1 and one of its transcript variants (n377360) in osteosarcoma cells and assess the role of TUG1 in proliferation and apoptosis in the U2OS cell line. Methods: TUG1 and n377360 expression levels in patients with osteosarcomas and the U2OS human osteosarcoma cell line were evaluated using real-time quantitative PCR. U2OS cells were transected with TUG1 and n377360 siRNA or non-targeting siRNA. MTS was performed to assess the cell proliferation and flow cytometry was applied to analyze apoptosis. Results: We found significantly higher TUG1 and n377360 expression levels in osteosarcoma tissues compared with matched non-tumorous tissues. In line with this, suppression of TUG1 and n377360 expression by siRNA significantly impaired the cell proliferation potential of osteosarcoma cells. Furthermore, inhibition of TUG1 expression significantly promoted osteosarcoma cell apoptosis. Conclusions: The overexpression of TUG1 and n377360 in osteosarcoma specimens and the functional role of TUG1 and n377360 regarding cell proliferation and apoptosis in an osteosarcoma cell line provided evidence that the use of TUG1 or n377360 may be a viable but an as yet unexplored therapeutic strategy in tumors that over express these factors.

Disturbance-Observer-Based Robust H<SUB>∞</SUB> Switching Tracking Control for Near Space Interceptor

GUO Chao,LIANG Xiao-Geng 한국항공우주학회 2014 International Journal of Aeronautical and Space Sc Vol.15 No.2

A novel robust H∞ switching tracking control design method with disturbance observer is proposed for the near space interceptor (NSI) with aerodynamic fins and reaction jets. Initially, the flight envelop of the NSI is divided into small subregions, and a slow-fast loop polytopic linear parameter varying (LPV) model is proposed, to approximate the nonlinear dynamic of the NSI, based on the Jacobian linearization and Tensor-Product (T-P) model transformation approach. A disturbance observer is then constructed, to estimate the modeled disturbance. Subsequently, based on the descriptor system method, a robust switching controller is developed, to ensure that the closed-loop descriptor system is stable with a desired H∞ disturbance attenuation level. Furthermore, the outcome of the proposed switching tracking control problem is formulated as a set of linear matrix inequalities (LMIs). Finally, simulation results demonstrate the effectiveness of the proposed design method.

Cooperative Guidance Law for Multiple Near Space Interceptors with Impact Time Control

GUO Chao,LIANG Xiao-Geng 한국항공우주학회 2014 International Journal of Aeronautical and Space Sc Vol.15 No.3

We propose a novel cooperative guidance law design method based on the finite time disturbance observer (FTDO) for multiple near space interceptors (NSIs) with impact time control. Initially, we construct a cooperative guidance model with head pursuit, and employ the FTDO to estimate the system disturbance caused by target maneuvering. We subsequently separate the cooperative guidance process into two stages, and develop the normal acceleration command based on the super-twisting algorithm (STA) and disturbance estimated value, to ensure the convergence of the relative distance. Then, we also design the acceleration command along the line-of-sight (LOS), based on the nonsingular fast terminal sliding mode (NFTSM) control, to ensure that all the NSIs simultaneously hit the target. Furthermore, we prove the stability of the closedloop guidance system, based on the Lyapunov theory. Finally, our simulation results of a three-to-one interception scenario show that the proposed cooperative guidance scheme makes all the NSIs hit the target at the same time.

LFT Modeling and Robust Stability Analysis of Missiles with Uncertain Parameters

HOU Zhen-qian,LIANG Xiao-geng,WANG Wen-zheng,LI Rui 한국항공우주학회 2014 International Journal of Aeronautical and Space Sc Vol.15 No.2

The structured singular value (μ) analysis based method has many advantages for the robust stability analysis of missiles with uncertain parameters. Nevertheless, the present linear fractional transformation (LFT) modeling process, which is the basis of μ analysis, is complex, and not suitable for automatic implementation; on the other hand, μ analysis requires a large amount of computation, which is a burden for large-scale application. A constructive procedure, which is computationally more efficient, and which may lead to a lower order realization than existing algorithms, is proposed for LFT modeling. To reduce the calculation burden, an analysis method is developed, based on skew μ. On this basis, calculation of the supremum of μ over a fixed frequency range converts into a single skew μ value calculation. Two algorithms are given, to calculate the upper and lower bounds of skew μ, respectively. The validity of the proposed method is verified through robust stability analysis of a missile with real uncertain parameters.

Optimal Controller for Near-Space Interceptor with Actuator Saturation

FAN Guo-long,LIANG Xiao-geng,HOU Zhen-qian,YANG Jun 한국항공우주학회 2013 International Journal of Aeronautical and Space Sc Vol.14 No.3

The saturation of the actuator impairs the response performance of the near space interceptor control system. A control system based on the properties of linear tracking system is designed for this problem. The properties are that the maximum value of the pseudo-Lyapunov function of the linear tracking control system do not present at the initial state but at the steady state, based on which the bounded stability problem is converted into linear tracking problem. The pseudo-Lyapunov function of the linear tracking system contain the input variables; the amplitude and frequency of the input variables affect the stability of the nonlinear control system. Designate expected closed-loop poles area for different input commands and obtain a controller which is function of input variables. The coupling between variables and linear matrices make the control system design problem non-convex. The non-convex problem is converted into a convex LMI according to the Shur complement lemma and iterative algorithm. Finally the simulation shows that the designed optimal control system is quick and accurate; the rationality of the presented design techniques is validated.