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Search Results: 1 - 10 of 149168 matches for " Lamei Zhao;Daquan Yang;Huiping Tian;Yuefeng Ji;Kun Xu "
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A Pole and Amc Point Matching Method for the Synthesis of Hsf-Uc-EBG Structure with Simultaneous Amc and EBG Properties
Lamei Zhao;Daquan Yang;Huiping Tian;Yuefeng Ji;Kun Xu
PIER , 2013, DOI: 10.2528/PIER12062406
Abstract: The relationship between the reflection phase curve and the dispersion curve of a H-shaped slot fractal uniplanar compact electromagnetic bandgap (HSF-UC-EBG) structure is investigated in this paper. It is demonstrated numerically and theoretically that the pole (located at phi = 180 degrees) of the reflection phase curve is related to the EBG location of the dispersion curve. More specifically, the pole is always located in the bandgap and the frequency shift characteristics of the pole and the EBG location are the same. Therefore, locations of the artificial magnetic conductor (AMC) and EBG can match with the AMC point and the pole, respectively. By realizing and making appropriate use of this, we can tailor the AMC and EBG locations to coincide in the frequency region only by reducing the spectral distance (d) between the AMC point and the pole. This method can improve the computational efficiency significantly. Parametric studies have been performed to obtain guidelines for reducing d. Finally, an example to design HSF-UC-EBG structure with simultaneous AMC and EBG properties by using this technique is presented with detail steps.
An investigation of the effect of intermediate layer in three-component planar photonic crystal waveguides
Hongjun Shen,Huiping Tian,Yuefeng Ji
Optica Applicata , 2009,
Abstract: The introduction of a third component into planar photonic crystal waveguides definitely influences the properties of linear defect modes, such as the band diagram, intrinsic loss, group velocity and group velocity dispersion. With the increase of the dielectric constant of the interlayer, the guided modes shift to lower frequencies and the radiative losses decrease in the frequency region of high group velocity of defect mode. The analysis of the sensitivity of a band diagram to the introduction of an interlayer reveals that the wider the planar photonic crystal waveguide and the thicker the slab, the more tolerant the overall structure. When one designs the real planar photonic crystal waveguides, the effect of unintentional intermediate layer on the optical properties of planar photonic crystal waveguides has to be taken into consideration. At the same time, the introduction of an intentional interlayer into macroporous planar photonic crystal waveguides can be utilized to optimize the design.
Nonlinearity-controllable all-optical logic gates based on broadband defect mode
Bin Liu,Huiping Tian,Hui Lu,Yuefeng Ji
Optica Applicata , 2010,
Abstract: To avoid the adverse effect of unstable nonlinear progress on the design of all-optical logic gates, the broadband defect mode of one-dimensional photonic crystal with dual-defects has been studied. By using transfer matrix method, influences of period number and refractive indices on crystal’s transmission spectrum are analyzed. It is pointed out that with proper parameters, broadband defect mode, which could be used to reduce the influence between the nonlinear refractive index and field distribution, can be gained. Due to this fact, the designed XOR, AND and NOT logic gates can be steadily controlled with low-threshold and high-contrast.
Unidirectional Dual-Band CPW-Fed Antenna Loaded with an AMC Reflector
Qun Luo,Huiping Tian,Zhitong Huang,Xudong Wang,Zheng Guo,Yuefeng Ji
International Journal of Antennas and Propagation , 2013, DOI: 10.1155/2013/875281
Abstract: A unidirectional dual-band coplanar waveguide fed antenna (DB-CPWFA) loaded with a reflector is presented in this paper. The reflector is made of an electric ground plane, a dielectric substrate, and artificial magnetic conductor (AMC) which shows an effective dual operational bandwidth. Then, the closely spaced AMC reflector is employed under the DB-DPWFA for performance improvement including unidirectional radiation, low profile, gain enhancement, and higher front-to-back (F/B) ratio. The final antenna design exhibits an 8% and 13% impedance bandwidths for 2.45?GHz and 5.8?GHz frequency regions, respectively. The overall gain enhancement of about 4?dB is achieved. The F/B ratio is approximate to 20?dB with a 16?dB improvement. The measured results are inconsistent with the numerical values. The presented design is a suitable candidate for radio frequency identification (RFID) reader application. 1. Introduction Over the past decade, radio frequency identification (RFID) technology is widely studied due to their tremendous applications. There are several frequency ranges assigned for this application such as 125?kHz, 13.56?MHz, 869?MHz, 902–928?MHz, 2.45 (2.400–2.483)?GHz, and 5.8 (5.725–5.875)?GHz [1]. Coplanar waveguide fed antenna (CPWFA) is well known as its wide bandwidth, light-weight, and ease of fabrication. What is more, CPWFA can easily achieve dual-band performance [2–4]. All above make it a good candidate for RFID application. However, when the radiator and GND are printed on one side of the substrate, the energy will be radiated bidirectionally. Thus, the antenna gain is usually very low, and this could be seen from [2–4] showing general gain value of 2–4?dBi. This does not satisfy the requirement of many cases which require high gain and unidirectional radiation. In order to improve the radiation performance for CPWFA, many efforts have been made. One of the typical methods is to put a reflector with an electric conducting surface at a distance of at least quarter-wavelength under the antenna [5], making it not suitable for low profile structure which requires overall height less than [6]. Artificial magnetic conductor (AMC) structure is famous for its property of in-phase reflection within a certain frequency range. Many researches are focused on the application of antennas loaded with AMC element to achieve low profile structure or to improve the impedance matching bandwidth [7–10]. The theory of achieving low profile structure could be illustrated in Figure 1. We can know that, by utilizing the AMC reflector, the space distance between
Expression of SATB1 Promotes the Growth and Metastasis of Colorectal Cancer
Yi Zhang, Xiuyun Tian, Hong Ji, Xiaoya Guan, Wei Xu, Bin Dong, Min Zhao, Meng Wei, Chunxiang Ye, Yuan Sun, Xiaosun Yuan, Chen Yang, Chunyi Hao
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0100413
Abstract: Special AT-rich sequence-binding protein-1 (SATB1) has been identified as a genome organizer that reprograms chromatin organization and transcription profiles. SATB1 promotes tumor growth and metastasis in breast cancer and is associated with poor prognosis in several cancer types. The association between SATB1 and colorectal cancer (CRC) has not been studied intensively. Therefore, this study aimed to investigate the effect of SATB1 on CRC growth and metastasis in vitro and in vivo and its correlation with overall survival and clinicopathological factors in CRC patients. Stable SATB1 knockdown and SATB1-overexpressing cell lines were established. SATB1 knockdown decreased cell growth, colony formation, migration, and invasion and increased apoptosis in CRC cells in vitro (p<0.05), whereas SATB1 overexpression had the opposite effect. SATB1 overexpression increased tumor growth and metastasis to lung and liver in vivo by using xenograft animal models (p<0.05). Thus, SATB1 promoted an aggressive CRC phenotype in vitro and in vivo. Immunohistochemical analysis of 560 CRC specimens showed that SATB1 expression was significantly higher in CRC tissues than in matched non-tumor mucosa (p<0.001). In addition, SATB1 expression was significantly higher in patients with poorly differentiated tumors, higher invasion depth, distant metastasis, and advanced TNM stage. SATB1-positive patients had a poorer prognosis than SATB1-negative patients, and SATB1 was identified as an independent prognostic factor for CRC (p = 0.009). Strikingly, we also evaluated SATB2 expression in CRC and found that SATB2 was more abundantly expressed in non-cancerous mucosa compared to colorectal cancer tissues (p<0.001). However, SATB2 expression had no influence on prognosis of CRC patients (p = 0.836). SATB1 expression was significantly associated with shorter survival time either in SATB2-positive patients or in SATB2-negative patients (p<0.001). In conclusion, our findings indicated an important role for SATB1 in CRC tumorigenesis and metastasis. Therefore, SATB1 may represent an important prognostic biomarker and therapeutic target for CRC.
Indicators of prognosis after liver transplantation in Chinese hepatocellular carcinoma patients
Jin Li, Lu-Nan Yan, Jian Yang, Zhe-Yu Chen, Bo Li, Yong Zeng, Tian-Fu Wen, Ji-Chun Zhao, Wen-Tao Wang, Jia-Yin Yang, Ming-Qing Xu, Yu-Kui Ma
World Journal of Gastroenterology , 2009,
Abstract: AIM: To identify prognostic factors of patients with hepatocellular carcinoma (HCC), who were treated by orthotopic liver transplantation (OLT).METHODS: From January 2000 to October 2006, 165 patients with HCC underwent OLT. Various clinicopathological risk factors for actuarial and recurrence-free survival were identified using the Kaplan-Meier method with the log-rank test. The Cox proportional hazards model was used to identify independently predictive factors for actuarial and recurrence-free survival, which were used to propose new selection criteria. We compared the outcome of the subgroup patients meeting different criteria. Survival analysis was performed using the Kaplan-Meier method with the log-rank test.RESULTS: The median follow-up was 13.0 mo (2.8-69.5 mo). Overall, 1-, 2-, 3- and 5-year actuarial survival was 73.3%, 45.6%, 35.4% and 32.1%, respectively. One-, 2-, 3- and 5-year overall recurrence-free survival was 67.0%, 44.3%, 34.5% and 34.5%, respectively. In univariate analysis, number of tumors, total tumor size, lobar distribution, differentiation, macrovascular invasion, microvascular invasion, capsulation of the tumor, and lymph node metastasis were found to be associated significantly with actuarial and tumor-free survival. By means of using the multivariate Cox proportional hazards model, total tumor size and macrovascular invasion were found to be independent predictors of actuarial and tumor-free survival. When the selection criteria were expanded into the proposed criteria, there was no significant difference in 1-, 2-, 3- and 5-year actuarial and tumor-free survival of the 49 patients who met the proposed criteria (97.6%, 82.8%, 82.8% and 82.8%, and 90.7%, 82.8%, 68.8% and 68.8%, respectively) compared with that of patients who met the Milan or University of California, San Francisco (UCSF) criteria.CONCLUSION: Macrovascular invasion and total tumor diameter are the strongest prognostic factors. The proposed criteria do not adversely affect the outcome of liver transplantation for HCC, compared with the Milan or UCSF criteria.
Microsurgical reconstruction of hepatic artery in A-A LDLT: 124 consecutive cases without HAT
Yi Yang, Lu-Nan Yan, Ji-Chun Zhao, Yu-Kui Ma, Bin Huang, Bo Li, Tian-Fu Wen, Wen-Tao Wang, Ming-Qing Xu, Jia-Yin Yang
World Journal of Gastroenterology , 2010,
Abstract: AIM: To retrospectively investigate microsurgical hepatic artery (HA) reconstruction and management of hepatic thrombosis in adult-to-adult living donor liver transplantation (A-A LDLT).METHODS: From January 2001 to September 2009, 182 recipients with end-stage liver disease underwent A-A LDLT. Ten of these patients received dual grafts. The 157 men and 25 women had an age range of 18 to 68 years (mean age, 42 years). Microsurgical techniques and running sutures with back-wall first techniques were performed in all arterial reconstructions under surgical loupes (3.5 ×) by a group of vascular surgeons. Intimal dissections were resolved by interposition of the great saphenous vein (GSV) between the donor right hepatic artery (RHA) and recipient common HA (3 cases) or abdominal aorta (AA) (2 cases), by interposition of cryopreserved iliac vessels between the donor RHA and recipient AA (2 cases).RESULTS: In the 58 incipient patients in this series, hepatic arterial thrombosis (HAT) was encountered in 4 patients, and was not observed in 124 consecutive cases (total 192 grafts, major incidence, 2.08%). All cases of HAT were suspected by routine color Doppler ultrasonographic examination and confirmed by contrast-enhanced ultrasound and hepatic angiography. Of these cases of HAT, two occurred on the 1st and 7th d, respectively, following A-A LDLT, and were immediately revascularized with GSV between the graft and recipient AA. HAT in one patient occurred on the 46th postoperative day with no symptoms, and the remaining case of HAT occurred on the 3rd d following A-A LDLT, and was cured by thrombolytic therapy combined with an anticoagulant but died of multiorgan failure on the 36th d after A-A LDLT. No deaths were related to HAT.CONCLUSION: Applying microsurgical techniques and selecting an appropriate anastomotic artery for HA reconstruction are crucial in reducing the high risk of HAT during A-A LDLT.
Photonic integrated technology for multi-wavelength laser emission
XiangFei Chen,Wen Liu,JunMing An,Yu Liu,Kun Xu,Xin Wang,JianGuo Liu,YueFeng Ji,NingHua Zhu
Chinese Science Bulletin , 2011, DOI: 10.1007/s11434-011-4677-7
Abstract: We summarized the design, fabrication challenges and important technologies for multi-wavelength laser transmitting photonic integration. Technologies discussed include multi-wavelength laser arrays, monolithic integration and modularizing coupling and packaging. Fabrication technique requirements have significantly declined with the rise of reconstruction-equivalent-chirp and second nanoimprint mask technologies. The monolithic integration problem between active and passive waveguides can be overcome with Butt-joint and InP array waveguide grating technologies. The dynamic characteristics of multi-factors will be simultaneously measured with multi-port analyzing modules. The performance of photonic integration chips is significantly improved with the autoecious factors compensation packaging technique.
Tacrolimus dosage requirements in living donor liver transplant recipients with small-for-size grafts
Fei Liu, Ya Li, Xiang Lan, Yong-Gang Wei, Bo Li, Lv-Nan Yan, Tian-Fu Wen, Ji-Chun Zhao, Ming-Qing Xu, Wen-Tao Wang, Jia-Yin Yang
World Journal of Gastroenterology , 2009,
Abstract: AIM: To investigate the tacrolimus dosage requirements and blood concentrations in adult-to-adult right lobe living donor liver transplantation (AALDLT) recipients with small-for-size (SFS) grafts.METHODS: During January 2007 and October 2008, a total of 54 cases of AALDLT with an observation period of 6 mo were enrolled in this study. The 54 patients were divided into two groups according to graft-recipient body weight ratio (GRBW): SFS grafts group (Group S, GRBW < 0.8%, n = 8) and non-SFS grafts group (Group N, GRBW ≥ 0.8%, n = 46). Tacrolimus 12-hour blood levels and doses were recorded during weeks 1, 2, 3 and 4 and months 2, 3, 4, 5 and 6 in group S and group N. Meanwhile, acute rejection rates, liver and renal function test results, and the number of potentially interacting medications were determined at each interval in the two groups. A comparison of tacrolimus dosage requirements and blood levels were made weekly in the first month post-surgery, and monthly from months 2 to 6.RESULTS: There were no differences in the demographic characteristics, acute rejection rates, liver and renal function test results, or the number of potentially interacting medications administered between the two groups. The tacrolimus dosage requirements in group S were significantly lower than group N at 2 wk (2.8 ± 0.4 mg/d vs 3.6 ± 0.7 mg/d, P = 0.006), 3 wk (2.9 ± 0.7 mg/d vs 3.9 ± 0.8 mg/d, P = 0.008), 4 wk (2.9 ± 0.8 mg/d vs 3.9 ± 1.0 mg/d, P = 0.023) and 2 mo (2.8 ± 0.7 mg/d vs 3.8 ± 1.1 mg/d, P = 0.033). Tacrolimus 12-h trough concentrations were similar between the two groups at all times except for 2 wk post-transplantation, when the concentrations were significantly greater in group S recipients than in group N recipients (11.3 ± 4.8 ng/mL vs 7.0 ± 3.8 ng/mL, P = 0.026).CONCLUSION: SFS grafts recipients have significantly decreased tacrolimus dosage requirements compared with non-SFS grafts recipients in AALDLT during the first 2 mo post-surgery.
Detection of a superconducting phase in a two-atom layer of hexagonal Ga film grown on semiconducting GaN(0001)
Huimin Zhang,Yi Sun,Wei Li,Junping Peng,Can-Li Song,Ying Xing,Qinghua Zhang,Jiaqi Guan,Zhi Li,Yanfei Zhao,Shuaihua Ji,Lili Wang,Ke He,Xi Chen,Lin Gu,Langsheng Ling,Mingliang Tian,Lian Li,X. C. Xie,Jianping Liu,Hui Yang,Qi-Kun Xue,Jian Wang,Xucun Ma
Physics , 2014, DOI: 10.1103/PhysRevLett.114.107003
Abstract: The recent observation of superconducting state at atomic scale has motivated the pursuit of exotic condensed phases in two-dimensional (2D) systems. Here we report on a superconducting phase in two-monolayer crystalline Ga films epitaxially grown on wide band-gap semiconductor GaN(0001). This phase exhibits a hexagonal structure and only 0.552 nm in thickness, nevertheless, brings about a superconducting transition temperature Tc as high as 5.4 K, confirmed by in situ scanning tunneling spectroscopy, and ex situ electrical magneto-transport and magnetization measurements. The anisotropy of critical magnetic field and Berezinski-Kosterlitz-Thouless-like transition are observed, typical for the 2D superconductivity. Our results demonstrate a novel platform for exploring atomic-scale 2D superconductor, with great potential for understanding of the interface superconductivity.
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