68 results on '"Lianghui Chen"'
Search Results
2. [Discussion on a new model of holistic treatment for chronic critical illness patients by internal cross-disciplinary team in the department of intensive care unit: clinical data analysis of a case of acute exacerbation of chronic obstructive pulmonary disease]
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Lianghui, Chen, Chaomin, Zheng, Xiaoqiong, Hong, Yongqiang, Chen, Xuri, Sun, and Yuqi, Liu
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Male ,Data Analysis ,Dacarbazine ,Pulmonary Disease, Chronic Obstructive ,Intensive Care Units ,Critical Illness ,Quality of Life ,Humans ,Middle Aged ,Respiratory Insufficiency - Abstract
To explore the effect of setting up an internal-cross disciplinary team (ICDT) in the intensive care unit (ICU) on a new model of overall treatment for patients with chronic critical illness (CCI).A 60-year-old male patient with acute exacerbation of chronic obstructive pulmonary disease (AECOPD) admitted to ICU in the Second Affiliated Hospital of Fujian Medical University was introduced. The role of ICDT composed of physicians, nurses, respiratory therapists, physiotherapists, clinical dietitians and patients' family members in ventilator withdrawal and super-early rehabilitation was analyzed in this case.The patient was diagnosed as AECOPD, type II aspiration penumonia respiratory failure, septic shock. The ICDT in ICU carried out early rehabilitation treatment for the patient on the basis of traditional infection control and supportive treatment. Under the care of the ICDT, peripheral blood white blood cell count (WBC), neutrophil count (NEU), procalcitonin (PCT), arterial partial pressure of carbon dioxide (PaCOICDT cooperation is very important for monitoring and treatment of CCI patients, which is beneficial to the super-early rehabilitation and prognosis improvement of critically ill patients.
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- 2022
3. Genetic association between TAP1 and TAP2 polymorphisms and ankylosing spondylitis: a systematic review and meta-analysis
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Genlin Wang, Yufeng Qian, Liang Tang, Feng Xue, Yan Wang, Huilin Yang, and Lianghui Chen
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medicine.medical_specialty ,Immunology ,Subgroup analysis ,Gastroenterology ,03 medical and health sciences ,0302 clinical medicine ,ATP Binding Cassette Transporter, Subfamily B, Member 3 ,Internal medicine ,medicine ,Humans ,Genetic Predisposition to Disease ,Spondylitis, Ankylosing ,ATP Binding Cassette Transporter, Subfamily B, Member 2 ,Genetic association ,030203 arthritis & rheumatology ,Pharmacology ,Ankylosing spondylitis ,biology ,business.industry ,Haplotype ,medicine.disease ,Rheumatology ,Meta-analysis ,biology.protein ,TAP2 ,TAP1 ,business ,030215 immunology - Abstract
Ankylosing spondylitis (AS) is a chronic inflammatory joint disease. The transporter associated with antigen processing (TAP) has been identified to play an important role in immune response as well as the HLA-associated diseases. The aim of our meta-analysis was to investigate the contribution of TAP (TAP1 and TAP2) polymorphisms to the risk of AS. Meta-analyses were performed between 2 polymorphisms in TAP1 (TAP1-333, -637) and 3 polymorphisms in TAP2 (TAP2-379, -565, and -665) and AS. The meta-analyses were involved with 6 studies with 415 cases and 659 controls. Significant association was found between TAP1-333Val, TAP1-637Gly, and TAP2-565Thr and AS compared with combined control group (TAP1-333Val: p = 0.009, OR = 1.40, 95% CI 1.09–1.80; TAP1-637Gly: p = 0.002, OR = 1.48, 95% CI 1.15–1.91; p = 0.03, OR = 1.38, 95% CI 1.04–1.84). Subgroup analysis shown that significant association was only found in AS when compared with HLA-B27-negative controls (TAP1-333Val: p = 0.004, OR = 1.53, 95% CI 1.14–2.06; TAP1-637Gly: p = 0.004, OR = 1.52, 95% CI 1.15–2.02; p = 0.02, OR = 1.56, 95% CI 1.09–2.24), but not in AS when compared with HLA-B27-positive controls (p > 0.05). Moreover, no significant associations were found between haplotypes in TAP1 and TAP2 in both the combined and the subgroup analyses (p > 0.05). TAP1-333Val, TAP1-637Gly, and TAP2-565Thr were likely to be associated with AS.
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- 2017
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4. Magnetic/Gold Core-Shell Hybrid Particles for Targeting and Imaging-Guided Photothermal Cancer Therapy
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Liangyu Zhou, Lianghui Chen, Pei Li, Zhiyong Qian, Yongsheng Li, Yanpeng Jia, Jinfeng Liao, Qiwen Li, and Dechao Niu
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Materials science ,Theranostic Nanomedicine ,0206 medical engineering ,Biomedical Engineering ,Pharmaceutical Science ,Medicine (miscellaneous) ,Bioengineering ,Nanotechnology ,02 engineering and technology ,Ferric Compounds ,Chitosan ,chemistry.chemical_compound ,Magnetics ,Mice ,Cell Line, Tumor ,Neoplasms ,Animals ,General Materials Science ,Surface charge ,Photothermal therapy ,Phototherapy ,021001 nanoscience & nanotechnology ,Ascorbic acid ,020601 biomedical engineering ,chemistry ,Particle ,Magnetic nanoparticles ,Particle size ,Gold ,0210 nano-technology - Abstract
The development of hybrid particles for tumor diagnosis and therapy has received considerable attention because they are capable of combining tumor diagnosis and treatment concurrently. So far hybrid particles for efficient and safe tumor theranostics are still very limited. Herein we have designed a new type of hybrid particles and evaluated its potential to be used in image-guided cancer diagnosis and therapy without the need of any toxic anticancer or contrast agents. The hybrid particles, consist of magnetic nanoparticles which are embedded in the poly(methyl methacrylate) (PMMA) cores and gold shells on chitosan (CTS) (γ-Fe2O3 @PMMA/CTS@Au). The hybrid particles were synthesized through initial formation of the core–shell structured γ-Fe2O3 @PMMA/CTS particles containing approximately 20% loading of magnetic nanoparticles. A gold layer was then built on top of the core–shell magnetic particles via a reduction of gold salt by amines from the chitosan assisted with the reducing agent NaBH4, followed by growing to complete gold shells in the presence of ascorbic acid (42.6% Au content). The properties of the composite particles including their chemical composition, morphology, particle size, size distribution, surface charge, magnetic responsiveness and photothermal ability were systematically characterized. The potential application of the γ-Fe2O3 @PMMA/CTS@Au hybrid particles in tumor diagnosis and therapy was assessed in vitro and in vivo using 4T1 tumor cells and 4T1 tumor-bearing mice through combining magnetic targeting, photoacoustic (PA)/computed tomography (CT) imaging and photothermal therapy. Results suggest that the γ-Fe2O3 @PMMA/CTS@Au particles can serve as a multifunctional tumor theranostic nanoplatform for magnetically targeted photothermal therapy. Breast cancer has been effectively eliminated without the use of any anticancer drugs or contrast agents. Therefore, this type of core–shell hybrid particles represents a new composite particle design for effective and safe tumor theranostics.
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- 2019
5. The Association between 5HT2A T102C and Behavioral and Psychological Symptoms of Dementia in Alzheimer’s Disease: A Meta-Analysis
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Liang Tang, Yiwei Chen, Yan Wang, Mei-Hua Bao, Huaiqing Luo, Ju Xiang, Lianghui Chen, Shui Zheng, Yungui Li, and Jian-Ming Li
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0301 basic medicine ,medicine.medical_specialty ,Psychosis ,Genotype ,Hallucinations ,lcsh:Medicine ,Review Article ,Disease ,Cochrane Library ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,0302 clinical medicine ,Alzheimer Disease ,Internal medicine ,Odds Ratio ,medicine ,Humans ,Dementia ,Receptor, Serotonin, 5-HT2A ,Apathy ,Psychiatry ,Depression (differential diagnoses) ,Polymorphism, Genetic ,General Immunology and Microbiology ,Depression ,business.industry ,lcsh:R ,General Medicine ,Odds ratio ,medicine.disease ,030104 developmental biology ,Psychotic Disorders ,Meta-analysis ,Linear Models ,medicine.symptom ,business ,030217 neurology & neurosurgery - Abstract
The serotonin receptor gene (5-HT2A) has been reported to be a susceptible factor in behavioral and psychological symptoms of dementia (BPSD) in Alzheimer’s disease (AD). However, previous results were conflicting. We aim to investigate the association of 5-HT2A T102C with BPSD in AD using a meta-analysis. Studies were collected using PubMed, Web of Science, the Cochrane Library databases, Chinese National Knowledge Infrastructure (CNKI), and Embase. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess associations. Nine studies with 1899 AD patients with/without BPSD were included in this meta-analysis. The 102C and CC genotypes were associated with psychosis in AD (102C: p<0.00001, OR [95% CI] = 3.19 [2.12–4.79]; CC: p<0.00001, OR [95% CI] = 7.24 [3.60–14.59]). The TT genotype was significantly associated with hallucinations, aberrant motor behavior, and psychosis in AD (hallucinations: p=0.001, OR [95% CI] = 0.52 [0.36–0.77]; aberrant motor behavior: p=0.03, OR [95% CI] = 0.58 [0.35–0.95]; and psychosis: p=0.002, OR [95% CI] = 0.34 [0.17–0.67]). No association was observed between T102C alleles or genotypes and delusions, agitation/aggression, depression, and apathy (p>0.05). Thus, the 5HT2A T102C might be a susceptible factor for hallucinations, aberrant motor behavior, and psychosis in AD. The potential mechanism of this polymorphism in BPSD in AD requires further exploration.
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- 2017
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6. Amphiphilic Core-Shell Nanocomposite Particles for Enhanced Magnetic Resonance Imaging
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Ki Lui, Dechao Niu, Cheng Hao Lee, Yuan Yao, Lianghui Chen, Kin Man Ho, and Pei Li
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Nanocomposite ,Materials science ,Nanoparticle ,02 engineering and technology ,General Chemistry ,equipment and supplies ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Chitosan ,chemistry.chemical_compound ,Crystallinity ,Nuclear magnetic resonance ,chemistry ,Amphiphile ,Particle ,Magnetic nanoparticles ,General Materials Science ,Particle size ,0210 nano-technology - Abstract
A scalable synthesis of magnetic core–shell nanocomposite particles, acting as a novel class of magnetic resonance (MR) contrast agents, has been developed. Each nanocomposite particle consists of a biocompatible chitosan shell and a poly(methyl methacrylate) (PMMA) core where multiple aggregated γ-Fe2O3 nanoparticles are confined within the hydrophobic core. Properties of the nanocomposite particles including their chemical structure, particle size, size distribution, and morphology, as well as crystallinity of the magnetic nanoparticles and magnetic properties were systematically characterized. Their potential application as an MR contrast agent has been evaluated. Results show that the nanocomposite particles have good stability in biological media and very low cytotoxicity in both L929 mouse fibroblasts (normal cells) and HeLa cells (cervical cancer cells). They also exhibited excellent MR imaging performance with a T2 relaxivity of up to 364 mMFe−1 s−1. An in vivo MR test performed on a naked mouse bearing breast tumor indicates that the nanocomposite particles can localize in both normal liver and tumor tissues. These results suggest that the magnetic core–shell nanocomposite particles are an efficient, inexpensive and safe T2-weighted MR contrast agent for both liver and tumor MR imaging in cancer therapy.
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- 2016
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7. Facile synthesis of gold/polymer nanocomposite particles using polymeric amine-based particles as dual reductants and templates
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Lianghui Chen, Noel Peter Bengzon Tan, Kin Man Ho, Yan Lu, Cheng Hao Lee, Matthias Ballauff, and Pei Li
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chemistry.chemical_classification ,Aqueous solution ,Nanocomposite ,Materials science ,Nanostructure ,Polymers and Plastics ,Polymer nanocomposite ,Organic Chemistry ,technology, industry, and agriculture ,Nanoparticle ,macromolecular substances ,Polymer ,chemistry ,Colloidal gold ,Polymer chemistry ,Materials Chemistry ,Amine gas treating - Abstract
Herein we report a facile synthesis of gold nanoparticle/polymer nanocomposite particles through a spontaneous reduction of tetrachloroauric (III) acid and encapsulation of resultant gold nanoparticles using amine-rich polymeric particles in water. The particle consisted of core–shell nanostructure with a dense layer of polyethyleneimine (PEI) shell. The hydrophilic PEI shell acted as a reductant to generate gold nanoparticles (AuNPs), while the particle as a polymer template to in-situ encapsulate and stabilize the resultant AuNPs, giving a stable gold/polymer nanocomposite particle in water. The PEI-based core–shell particles with different degree of softness were found to have little influence on the reduction ability of the gold salt, but considerablely affect the encapsulating capability. Increasing the level of softness of particle core gave higher encapsulation efficiency to the gold nanoparticles. A soft type of core–shell microgel, namely poly( N -isopropyl acrylamide)/polyethyleneimine (PNIPAm/PEI) was further investigated with respect to the reduction rate, encapsulation efficiency, as well as nanocomposite stability and properties. Results indicated that reduction rate of gold salts using the PNIPAm/PEI microgels as the reductant was two orders of magnitude faster than that of the native PEI. Solution pH and amine to gold salt ratio also affected the formation of Au@PNIPAm/PEI composite particles. Our results demonstrate that the use of polymeric amine-based particles is a simple and green synthesis of Au@polymer nanocomposite particles in aqueous system which is free from organic solvent, reducing and stabilizing agents.
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- 2015
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8. Synthesis and characterization of a novel macromolecular surface modifier for polyethylene
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Yi Zhang, Siwei Liu, Zhenguo Chi, Jiarui Xu, Min-min Zhang, and Lianghui Chen
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Thermogravimetric analysis ,Materials science ,Polymers and Plastics ,General Chemical Engineering ,Organic Chemistry ,Radical polymerization ,technology, industry, and agriculture ,Polyethylene ,Methacrylate ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Attenuated total reflection ,Polymer chemistry ,Copolymer ,Methyl methacrylate ,Ethylene glycol - Abstract
A new macromolecular surface modifier, a copolymer of lauryl methacrylate (LMA) and poly(ethylene glycol) methyl methacrylate (PEGMA), was synthesized through free radical polymerization. The copolymer was characterized by nuclear magnetic resonance spectrum (1H-NMR) and thermogravimetric analysis (TGA). The copolymer was used to blend with polyethylene. The binary blends have been characterized by attenuated total reflection/Fourier transform infrared (ATRFTIR), contact-angle measurements (CDA) and scanning electron microscopy (SEM). The results indicated that poly(ethylene glycol) methyl methacrylate-co-lauryl methacrylate (PEGMA-co-LMA) could diffuse preferably onto the surface of the polyethylene (PE) film, and thus can be used as an efficient surface modifier for PE.
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- 2013
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9. TLR4 rs41426344 increases susceptibility of rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA) in a central south Chinese Han population
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Mei-Hua Bao, Ju Xiang, Yan Wang, Huaiqing Luo, Liang Tang, Fang Li, Lianghui Chen, Jie Zeng, and Jian-Ming Li
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0301 basic medicine ,Adult ,Male ,medicine.medical_specialty ,China ,Genotype ,Arthritis ,Gastroenterology ,Polymorphism, Single Nucleotide ,Juvenile idiopathic arthritis (JIA) ,Arthritis, Rheumatoid ,03 medical and health sciences ,0302 clinical medicine ,Rheumatology ,Asian People ,Gene Frequency ,Internal medicine ,medicine ,Immunology and Allergy ,Humans ,Genetic Predisposition to Disease ,Pediatrics, Perinatology, and Child Health ,Child ,Genotyping ,Toll like receptors 4 (TLR4) ,Genetic association ,030203 arthritis & rheumatology ,business.industry ,Haplotype ,medicine.disease ,Arthritis, Juvenile ,Chinese Han population ,Toll-Like Receptor 4 ,Exact test ,030104 developmental biology ,Haplotypes ,Rheumatoid arthritis ,Rheumatoid arthritis (RA) ,Pediatrics, Perinatology and Child Health ,Female ,business ,Research Article - Abstract
Background The aim of the study was to determine whether polymorphisms in toll-like receptor 4 (TLR4) confer susceptibility to rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA) in a central south Chinese Han population. Methods Genotyping for six well studied polymorphisms (rs4986790, rs4986791, rs10759932, rs41426344, rs11536889 and rs7873784) in TLR4 gene were conducted in 1074 unrelated patients with RA and 1692 healthy control subjects, as well as in 217 unrelated patients with JIA and 378 healthy control subjects using direct sequencing technique. Comparisons between cases and controls in alleles, genotypes and haplotypes were carried out using Fisher’s exact test. Results Significant genetic associations were detected between the 3’UTR rs41426344C and RA (p
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- 2017
10. Additional file 1: Table S1. of TLR4 rs41426344 increases susceptibility of rheumatoid arthritis (RA) and juvenile idiopathic arthritis (JIA) in a central south Chinese Han population
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Wang, Yan, Lianghui Chen, Li, Fang, Meihua Bao, Zeng, Jie, Xiang, Ju, Huaiqing Luo, Jianming Li, and Tang, Liang
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lipids (amino acids, peptides, and proteins) - Abstract
The PCR and sequencing primers of TLR4 SNPs. (DOC 30 kb)
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- 2017
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11. Regulation of membrane fixation and energy production/conversion for adaptation and recovery of ZnO nanoparticle impacted Nitrosomonas europaea
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Lianghui Chen, Ran Yu, Yan Chang, Guangcan Zhu, Huijie Lu, and Junkang Wu
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0301 basic medicine ,Membrane permeability ,Nitrogen ,Acclimatization ,Cell ,Nitrosomonas europaea ,Oxidative phosphorylation ,Chemostat ,010501 environmental sciences ,01 natural sciences ,Applied Microbiology and Biotechnology ,03 medical and health sciences ,chemistry.chemical_compound ,Bioreactors ,Ammonia ,medicine ,Nitrite ,Cell damage ,Nitrites ,0105 earth and related environmental sciences ,biology ,General Medicine ,Gene Expression Regulation, Bacterial ,biology.organism_classification ,medicine.disease ,Microarray Analysis ,Adaptation, Physiological ,Carbon ,Oxygen ,030104 developmental biology ,medicine.anatomical_structure ,Biochemistry ,chemistry ,Biophysics ,Nanoparticles ,Osmoprotectant ,Zinc Oxide ,Energy Metabolism ,Oxidoreductases ,Glycolysis ,Oxidation-Reduction ,Metabolic Networks and Pathways ,Biotechnology - Abstract
The ZnO nanoparticle (NP) effects on typical ammonia-oxidizing bacteria, Nitrosomonas europaea in a chemostat bioreactor, and the cells’ toxicity adaptation and recovery potentials were explored. Hardly any inhibition was observed when the NP concentration was high up to 10 mg/L. The cells exposed to 50 mg/L ZnO NPs displayed time-dependent impairment and recovery potentials in terms of cell density, membrane integrity, nitrite production rate, and ammonia monooxygenase activity. The 6-h NP stress impaired cells were nearly completely restored during a 12-h recovery incubation, while the longer exposure time would cause irretrievable cell damage. Microarray analysis further indicated the transcriptional adaptation of N. europaea to NP stress. The regulations of genes encoding for membrane permeability or osmoprotectant, membrane integrity preservation, and inorganic ion transport during NP exposure and cell recovery revealed the importance of membrane fixation and the associated metabolisms for cells’ self-protection and the following recovery from NP stress. The oxidative phosphorylation, carbon assimilation, and tricarboxylic acid (TCA) cycling pathways involved in the cells’ antitoxicity activities and would promote the energy production/conversion efficiency for cell recovery. The heavy metal resistance, histidine metabolism, toxin-antitoxin defense, glycolysis, and sulfate reduction pathways were also suggested to participate in the cell detoxication and recovery processes. All these findings provided valuable insights into the mechanisms of cell-mediated ZnO NP cytotoxicity and their potential impacts on wastewater nitrogen removal system.
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- 2016
12. High-Performance Functional Polyimides Containing Rigid Nonplanar Conjugated Triphenylethylene Moieties
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Yi Zhang, Lianghui Chen, Yiwu Liu, Siwei Liu, Zexin Qin, Jiarui Xu, Qi Lan, Zhenguo Chi, Cunyuan Zhao, and James Economy
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Materials science ,General Chemical Engineering ,General Chemistry ,Dielectric ,Conjugated system ,Fluorescence ,Indium tin oxide ,chemistry.chemical_compound ,chemistry ,Suzuki reaction ,Diamine ,Polymer chemistry ,Materials Chemistry ,Thermal stability ,Glass transition - Abstract
A novel, simple but efficient diamine (TriPEDA) containing rigid nonplanar conjugated triphenylethylene moieties was designed and synthesized through Wittig–Horner and Suzuki coupling reactions. Four kinds of high-performance functional polyimides were thus prepared by the dipolymerization of TriPEDA and four dianhydrides, respectively. Because of the introduction of the aromatic rigid nonplanar triphenylethylene structure, the polyimides exhibited special fluorescent and resistive switching (ON-OFF) characteristics, as the maximum fluorescence emission of the four polyimides was observed at 472–505 nm in NMP solution and at 473–541 nm in film state. Also these organo-soluble polyimides showed outstanding properties, such as low dielectric constant (even without fluorinated substituents), light color, high glass transition temperatures (359–409 °C), thermal stability, and excellent mechanical properties. The memory devices with the configuration of indium tin oxide/polyimides/aluminum (ITO/PI/Al) exhibite...
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- 2012
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13. Optical amplification based on slow light effects in the photonic crystal waveguide
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Yejin Zhang, Hongwei Qu, Lianghui Chen, Aiyi Qi, and Wanhua Zheng
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Physics ,business.industry ,Technology research ,Finite-difference time-domain method ,Condensed Matter Physics ,Laser ,Slow light ,Polarization (waves) ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,law.invention ,Photonic crystal waveguides ,law ,Basic research ,Optoelectronics ,Electrical and Electronic Engineering ,business ,Photonic crystal - Abstract
chinese national key basic research special fund/cnkbrsf[2006cb921705, 2011cb922002]; national natural science foundation of china[10634080, 60677046, 60838003]; national high technology research and development program of china[2007aa03z410, 2007aa03z408]
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- 2011
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14. Fabrication of biomimic GaAs subwavelength grating structures for broadband and angular-independent antireflection
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Xi Chen, Zhongchao Fan, Yun Xu, Guofeng Song, and Lianghui Chen
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Fabrication ,Materials science ,business.industry ,Grating ,Condensed Matter Physics ,Atomic packing factor ,Atomic and Molecular Physics, and Optics ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Interference lithography ,Wavelength ,Optics ,Etching (microfabrication) ,Reflection (physics) ,Optoelectronics ,Electrical and Electronic Engineering ,Inductively coupled plasma ,business - Abstract
We combine interferometric lithography and inductively coupled plasma etching to fabricate GaAs subwavelength grating (SWG) which mimics the moth eye structures. Through the modification of morphology parameters, including profile, height and packing fraction, tapered, high-aspect-ratio and closely-packed GaAs SWGs are obtained. The measurement of spectral reflectance of the fabricated SWGs shows that reflection has been dramatically reduced compared to the polished GaAs surface. Particularly, the optimized SWG structures exhibit an average reflection below 5% in the wavelengths ranging from 350 to 900 nm. Furthermore, the angular-independent property is demonstrated by measuring the reflectance versus varying angles of incidence at 532 and 632.8 nm wavelengths.
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- 2011
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15. Light emission of heavily doped AlGaN structures under optical pumping
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K. S. Zhuravlev, I.V. Osinnykh, Lianghui Chen, P. A. Bokhan, Xin Wei, Dm. E. Zakrevsky, N.V. Fateev, Jian Li, and Timur V. Malin
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010302 applied physics ,Materials science ,business.industry ,Terahertz radiation ,Band gap ,Doping ,Physics::Optics ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Semimetal ,Electronic, Optical and Magnetic Materials ,Optical pumping ,Condensed Matter::Materials Science ,0103 physical sciences ,Materials Chemistry ,Optoelectronics ,Light emission ,Electrical and Electronic Engineering ,0210 nano-technology ,business ,Luminescence ,Molecular beam epitaxy - Abstract
Spectral, temporal and polarization characteristics of spontaneous and stimulated luminescence of Al 0.5 Ga 0.5 N/AlN structures grown by molecular beam epitaxy were studied at the optical pulsed pumping with λ = 266 nm. Samples with a high degree of silicon doping were investigated. The vast majority of radiation falls on transitions within the band gap between the levels of defects. As a result, the radiation band embracing the whole visible range of more than 300 THz is observed in both spontaneous radiation and induced luminescence. In spontaneous radiation the band has a smooth spectral intensity distribution over the wavelengths, whereas induced radiation has its sharp peaks corresponding to the mode structure of the planar waveguide. The measured gain of the active medium is g ≈ 70 cm −1 for a weak signal.
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- 2018
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16. Resonant Enhanced Wave Filter and Waveguide via Surface Plasmons
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Lianghui Chen, Baoshan Guo, and Guofeng Song
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Materials science ,business.industry ,Surface plasmon ,Physics::Optics ,Dielectric ,Ray ,Computer Science Applications ,law.invention ,Wavelength ,Optics ,Surface wave ,law ,Dielectric loss ,Electrical and Electronic Engineering ,business ,Waveguide ,Plasmon - Abstract
The authors present an analysis of plasmonic wave filter and curved waveguide, simulated using a 2-D finite-difference time-domain technique. With different dielectric materials or surface structures located on the interface of the metal/dielectric, the resonant enhanced wave filter can divide light waves of different wavelengths and guide them with low losses. And the straight or curved waveguide can confine and guide light waves in a subwavelength scale. Within the 20 mum simulation region, it is found that the intensity of the guided light at the interface is roughly four times the peak intensity of the incident light.
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- 2009
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17. Application of fast Pade approximation in simulating photonic crystal nanocavities by FDTD technology
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Yejin Zhang, Gang Ren, Mingxin Xing, Hailing Wang, Lianghui Chen, and Wanhua Zheng
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Physics ,Signal processing ,Multi-mode optical fiber ,business.industry ,Finite-difference time-domain method ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Optics ,Position (vector) ,Q factor ,Padé approximant ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,business ,Photonic crystal ,Interpolation - Abstract
The exact calculation of mode quality factor Q is a key problem in the design of high-Q photonic crystal nanocavity. On the basis of further investigation on conventional Pade approximation, FDM and DFT, Pade approximation with Baker's algorithm is enhanced through introducing multiple frequency search and parabola interpolation. Though Pade approximation is a nonlinear signal processing method and only short time sequence is needed, we find the different length of sequence requirements for 2D and 3D FDTD, which is very important to obtain convergent and accurate results. By using the modified Pade approximation method and 3D FDTD, the 2D slab photonic crystal nanocavity is analyzed and high-Q multimode can be solved quickly instead of large range high-resolution scanning. Monitor position has also been investigated. These results are very helpful to the design of photonic crystal nanocavity devices. (C) 2008 Elsevier B.V. All rights reserved.
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- 2008
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18. Numerical study of sub-wavelength plasmonic waveguide
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Guofeng Song, Baoshan Guo, and Lianghui Chen
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Materials science ,Aperture ,business.industry ,Numerical analysis ,Nanophotonics ,Ray ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Wavelength ,Optics ,Plasmonic waveguide ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,business ,Intensity (heat transfer) ,Plasmon - Abstract
The authors present an analysis of a plasmonic waveguide, simulated using a two-dimensional finite-difference time-domain technique. With the surface structures located on the surface of the metal, the device is able to confine and guide light waves in a sub-wavelength scale. And two waveguides can be placed within 150 nm (similar to 6% of the incident wavelength) that will helpful for the optoelectronic integration. Within the 20 mu m simulation region, it is found that the intensity of the guided light at the interface is roughly two to four times the peak intensity of the incident light, and the propagation length can reach approximately 40 Pm at the wavelength of 2.44 mu m. (c) 2007 Elsevier B.V. All rights reserved.
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- 2008
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19. Numerical Study of a High-Resolution Far-Field Scanning Optical Microscope via a Surface Plasmon-Modulated Light Source
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Lianghui Chen, Guofeng Song, Qiaoqiang Gan, Jianxia Gao, and Baoshan Guo
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Materials science ,business.industry ,Surface plasmon ,Near-field optics ,Near and far field ,Extraordinary optical transmission ,Grating ,Surface plasmon polariton ,Atomic and Molecular Physics, and Optics ,law.invention ,Optics ,Optical microscope ,law ,Near-field scanning optical microscope ,business - Abstract
In this paper, we analyze light transmission through a single subwavelength slit surrounded by periodic grooves in layered films consisting of Au and dielectric material. A subwavelength grating is scanned numerically by the finite difference time domain method in two dimensions. The results show that the transmission field can be confined to a spot with subwavelength width in the far field and can be useful in the application of a high-resolution far-field scanning optical microscope
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- 2007
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20. Toxicity of binary mixtures of metal oxide nanoparticles to Nitrosomonas europaea
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Meiting Liu, Huijie Lu, Yan Chang, Ran Yu, Junkang Wu, Guangcan Zhu, and Lianghui Chen
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Environmental Engineering ,Health, Toxicology and Mutagenesis ,Inorganic chemistry ,chemistry.chemical_element ,Nanoparticle ,Metal Nanoparticles ,Nitrosomonas europaea ,02 engineering and technology ,Zinc ,Microbial Sensitivity Tests ,010501 environmental sciences ,01 natural sciences ,chemistry.chemical_compound ,Environmental Chemistry ,Solubility ,Cytotoxicity ,0105 earth and related environmental sciences ,Titanium ,biology ,Sewage ,Cell Membrane ,technology, industry, and agriculture ,Public Health, Environmental and Occupational Health ,General Medicine ,General Chemistry ,Cerium ,021001 nanoscience & nanotechnology ,biology.organism_classification ,Pollution ,chemistry ,Nanotoxicology ,Toxicity ,Titanium dioxide ,Zinc Oxide ,0210 nano-technology ,Oxidation-Reduction ,Nuclear chemistry - Abstract
Although the widely used metal oxide nanoparticles (NPs) titanium dioxide NPs (n-TiO2), cerium dioxide NPs (n-CeO2), and zinc oxide NPs (n-ZnO) have been well known for their potential cytotoxicities to environmental organisms, their combined effects have seldom been investigated. In this study, the short-term binary effect of n-CeO2 and n-TiO2 or n-ZnO on a model ammonia oxidizing bacterium, Nitrosomonas europaea were evaluated based on the examinations of cells' physiological, metabolic, and transcriptional responses. The addition of n-TiO2 mitigated the negative effect of more toxic n-CeO2 and the binary toxicity (antagonistic toxicity) of n-TiO2 and n-CeO2 was generally lower than the single NPs induced one. While the n-CeO2/n-ZnO mixture exerted higher cytotoxicity (synergistic cytotoxicity) than that from single NPs. The increased addition of the less toxic n-CeO2 exaggerated the binary toxicity of n-CeO2/n-ZnO mixture although the solubility of n-ZnO was not significantly affected, which excluded the contribution of the dissolved Zn ions to the enhancement of the combined cytotoxicity. The cell membrane disturbances and NP internalizations were detected for all the NP impacted cultures and the electrostatic interactions among the two distinct NPs and the cells were expected to play a key role in mediating their direct contacts and the eventual binary nanotoxicity to the cells.
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- 2015
21. High-power and low-loss room temperature operation of 2.4μm GaInAsSb/AlGaAsSb type-I strained quantum-well laser diodes
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Yu Zhang, Yuzhi Song, Jiakun Song, Lianghui Chen, Kangwen Li, Song Guofeng, and Yun Xu
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Materials science ,Laser diode ,business.industry ,Laser ,law.invention ,Semiconductor laser theory ,Optics ,law ,Optoelectronics ,Quantum efficiency ,Quantum well laser ,business ,Quantum well ,Molecular beam epitaxy ,Diode - Abstract
High power GaSb based type-I GaInAsSb/AlGaAsSb three quantum wells laser diodes emitting at 2.4 μm were optimized and fabricated. The laser wafer was grown with solid source Molecular Beam Epitaxy System. With optimizations of the epitaxial structure design and the ohmic contact, the operation voltage and the internal loss decreased; the internal quantum efficiency and output power increased. The internal quantum efficiency was determined about 80.1% and the internal loss was 12 cm -1 by measuring laser diodes with different cavity lengths. An uncoated 2-mm-long laser diode with 90-μm-wide aperture exhibited a threshold current density of 222 A/cm 2 (74 A/cm 2 per quantum well), a continuous wave output power of 232 mW and a quasi-continuous wave (1 kHz, 10 μs) output power of 1 W at room temperature.
- Published
- 2015
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- View/download PDF
22. Characteristics of InGaN multiple quantum well blue-violet laser diodes
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J.W. Liang, Degang Zhao, Jianjun Zhu, Jun Chen, Shuming Zhang, Lianghui Chen, Zongshun Liu, Jianfeng Wang, Ming Chong, Hui Yang, and Deyao Li
- Subjects
Distributed feedback laser ,Blue laser ,Materials science ,Laser diode ,business.industry ,Far-infrared laser ,Physics::Optics ,Laser ,law.invention ,law ,Quantum dot laser ,Electro-absorption modulator ,Optoelectronics ,Physics::Atomic Physics ,business ,Diode - Abstract
Studies on InGaN multiple quantum well blue-violet laser diodes have been reported. Laser structures with long-period multiple quantum wells were grown by metal-organic chemical vapor deposition. Triple-axis X-ray diffraction (TAXRD) measurements show that the multiple quantum wells were high quality. Ridge waveguide laser diodes were fabricated with cleaved facet mirrors. The laser diodes lase at room temperature under a pulsed current. A threshold current density of 3.3 kA/cm2 and a characteristic temperature T0 of 145 K were observed for the laser diode.
- Published
- 2006
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23. Two-dimensional simulation of high-order laterally-coupled GaAs-AlGaAs DFB laser diodes
- Author
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Guofeng Song, Yuan Zhong, Yidong Huang, Xiaopeng Zhu, and Lianghui Chen
- Subjects
Distributed feedback laser ,Fabrication ,Materials science ,business.industry ,Finite difference method ,Optical field ,Condensed Matter Physics ,Laser ,Electronic, Optical and Magnetic Materials ,law.invention ,Transverse plane ,Optics ,law ,Materials Chemistry ,Electrical and Electronic Engineering ,business ,Coupling coefficient of resonators ,Diode - Abstract
Laterally-coupled distributed feedback (LC-DFB) laser diodes made without an epitaxial re-growth process have the advantage of a simple fabrication process. In this paper, two-dimensional optical field distribution of the fundamental quasi TE (transverse electric) mode is calculated by means of a semivectorial finite-difference method (SV-FDM). The dependence of the effective coupling coefficient (kappa(eff)) on the dutycycle of first-, second- and third-order LC-DFB LDs is investigated using modified coupled wave equations.
- Published
- 2004
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24. Effect of metal contact's reflection on the effective coupling coefficient of second-order DFB laser diodes
- Author
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Guofeng Song, Yuan Zhong, Lianghui Chen, Yidong Huang, and Xiaopeng Zhu
- Subjects
Distributed feedback laser ,Materials science ,business.industry ,Radiation ,Condensed Matter Physics ,Laser ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,law.invention ,Metal ,Optics ,Reflection (mathematics) ,law ,visual_art ,visual_art.visual_art_medium ,Optoelectronics ,Contact layer ,Electrical and Electronic Engineering ,business ,Coupling coefficient of resonators ,Diode - Abstract
For a second-order DFB-LD, the presence of a metal contact layer can reduce I-st-order radiation. Part of the reflected power is redistributed into guided modes and results in a variation of the effective coupling coefficient kappa(eff). In this paper, we study the effect of the Au top contact's reflection on the kappa(eff) of 2(nd)-order DFB lasers. (C) 2004 Wiley Periodicals, Inc.
- Published
- 2004
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25. Additive, dominant parental effects control the inheritance of grain cadmium accumulation in hybrid rice
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Jinpeng Dai, Lianghui Chen, Guoyu Zhang, Jiurong Wang, Guoying Xiao, Fei Yang, D. Mao, Hao Zhou, Liang Sun, Wenyuan Yao, and Caiyan Chen
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education.field_of_study ,Heterosis ,Population ,food and beverages ,Plant Science ,Mating design ,Heritability ,Biology ,Crop ,Diallel cross ,Agronomy ,Genetics ,Cultivar ,education ,Agronomy and Crop Science ,Molecular Biology ,Biotechnology ,Hybrid - Abstract
Rice, a staple crop for more than half of the world’s population, takes up and accumulates more cadmium (Cd) than do other cereal crops (Chaney et al. in Z Naturforsch C 60(3–4):190–198, 2005). Rice is the leading source of dietary Cd for people who consume rice as their main food resource. A low grain Cd (GCd) concentration is a highly desirable trait for food safety. Low GCd is a top priority target in hybrid rice breeding, which dominates the rice-growing areas with high Cd bioavailability in southern China and South Asia. Thus, the genetic controls of grain Cd accumulation need to be dissected to facilitate the breeding of low grain Cd cultivars. In this study, the genetics of GCd accumulation in hybrids was analyzed in 24 hybrids using a 3 × 8 incomplete diallel mating design in two Cd-polluted fields. Estimates for narrow heritability and combining ability, including both general combining ability (GCA) and specific combining ability, revealed the importance of additive gene effects from both parental lines in determining grain Cd concentration in hybrid rice, suggesting that hybrids do not necessarily show high GCd in the case of effective additive effects from the parents. In addition, we found that the average values for GCA effects and the mid-parent values for Cd in node I after heading could be used as effective predictors for selecting parental lines for breeding low-Cd hybrids. Of 11 parental lines, 108A, Yifeng26A, Yifeng98A, AnfengA, 11C2292, and 11C2265 were found to be the better cytoplasmic male sterile and/or restorer lines for breeding low GCd hybrids. Of the 24 hybrid combinations, considering yield performance, six of the crosses in our study were identified as hybrids that had low grain Cd levels without losing their yield advantages.
- Published
- 2015
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- View/download PDF
26. High power 980 nm Al-free strained quantum-well lasers for erbium-doped fiber amplifiers
- Author
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Zuntu Xu, Lianghui Chen, Guowen Yang, Xiaoyu Ma, Junying Xu, and Jingming Zhang
- Subjects
Materials science ,business.industry ,Organic Chemistry ,Slope efficiency ,Far-infrared laser ,Single-mode optical fiber ,Chemical vapor deposition ,Laser ,Waveguide (optics) ,Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials ,Semiconductor laser theory ,law.invention ,Inorganic Chemistry ,Optics ,law ,Electrical and Electronic Engineering ,Physical and Theoretical Chemistry ,business ,Spectroscopy ,Quantum well - Abstract
In this paper, we reported on the fabrication of 980 nm InGaAs/InGaAsP strained quantum-well (QW) lasers with broad waveguide. The laser structure was grown by low-pressure metalorganic chemical vapor deposition on a n(+)- GaAs substrate. For 3 mu m stripe ridge waveguide lasers, the threshold current is 30 mA and the maximum output power and the output power operating in fundamental mode are 350 mW and 200 mW, respectively. The output power from the single mode fiber is up to 100 mW, the coupling efficiency is 50%. We also fabricated 100 mu m broad stripe coated lasers with cavity length of 800 mu m, a threshold current density of 170 A/cm(2), a high slope efficiency of 1.03 W/A and a far-field pattern of 40 x 6 degrees are obtained. The maximum output power of 3.5 W is also obtained for 100 mu m wide coated lasers. (C) 2000 Elsevier Science B.V. All rights reserved.
- Published
- 2000
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27. QUANTUM WELL LASERS AND THEIR APPLICATIONS
- Author
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Lianghui Chen
- Subjects
Materials science ,Optical fiber ,Laser diode ,business.industry ,Quantum wire ,Laser ,Electronic, Optical and Magnetic Materials ,law.invention ,Wavelength ,Optics ,Hardware and Architecture ,law ,Quantum dot laser ,Optoelectronics ,Quantum well laser ,Electrical and Electronic Engineering ,business ,Quantum well - Abstract
Quantum well lasers have attracted a great deal of attention by their many advantages such as low threshold current density, excellent temperature feature, high modulation rate and wavelength adjustability etc. The investigation on quantum well laser in mainland China started in the early 80s. AlGaAs/GaAs QW laser diode and InGaAs/GaAs strained layer QW laser diode have been developed using MBE technology with extremely low threshold current and high T0. Now the growth technologies for QW structure have been expanded to MOCVD technology. Emission wavelengths, on longer wavelength sides have been expanded up to 1.3 µm and 1.55 µm with InGaAsP/InP material system for application in optical fiber communication. On shorter wavelength sides, the emission wavelength has been expanded to lower than 670 nm, for applications in optical information processing. The characteristics of these devices will be demonstrated in this paper. The QW-DFB LD and low-dimension quantum wire and quantum dot lasers are under investigation.
- Published
- 1996
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- View/download PDF
28. Efficient self-consistent Schrödinger–Poisson-rate equation iteration method for the modeling of strained quantum cascade lasers
- Author
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Xunpeng Ma, Xin Wei, Yu Jiang, Guofeng Song, Jian Li, Dong Fu, Haoyue Wu, and Lianghui Chen
- Subjects
Physics ,Electron density ,Acoustics and Ultrasonics ,Scattering ,02 engineering and technology ,Rate equation ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Computational physics ,Schrödinger equation ,symbols.namesake ,020210 optoelectronics & photonics ,Effective mass (solid-state physics) ,Cascade ,Quantum mechanics ,0202 electrical engineering, electronic engineering, information engineering ,symbols ,0210 nano-technology ,Hamiltonian (quantum mechanics) ,Quantum - Abstract
We present an efficient method for the calculation of the transmission characteristic of quantum cascade lasers (QCLs). A fully Schrodinger–Poisson-rate equation iteration with strained term is presented in our calculation. The two-band strained term of the Schrodinger equation is derived from the eight-band Hamiltonian. The equivalent strain energy that affects the effective mass and raises the energy level is introduced to include the biaxial strain into the conduction band profile. We simplified the model of the electron–electron scattering process and improved the calculation efficiency by about two orders of magnitude. The thermobackfilling effect is optimized by replacing the lattice temperature with the electron temperature. The quasi-subband-Fermi level is used to calculate the electron density of laser subbands. Compared with the experiment results, our method gives reasonable threshold current (depends on the assumption of waveguide loss and scattering processes) and more accurate wavelength, making the method efficient and practical for QCL simulations.
- Published
- 2016
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29. Absorption and interaction of the main constituents from the traditional Chinese drug pair Shaoyao-Gancao via a Caco-2 cell monolayer model
- Author
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Lu Wang, Lianghui Chen, Yan Chen, Jinyan Wang, and Qingqing Wu
- Subjects
Bridged-Ring Compounds ,Pharmaceutical Science ,interaction ,Decoction ,Absorption (skin) ,Paeonia ,Benzoates ,Intestinal absorption ,Article ,Analytical Chemistry ,lcsh:QD241-441 ,chemistry.chemical_compound ,paeoniflorin ,liquiritin ,glycyrrhizic acid ,extract ,absorption ,Caco-2 cell monolayer model ,lcsh:Organic chemistry ,Glucosides ,Drug Discovery ,medicine ,Humans ,ATP Binding Cassette Transporter, Subfamily B, Member 1 ,Physical and Theoretical Chemistry ,Chromatography ,Organic Chemistry ,Biological Transport ,Paeoniflorin ,Glycyrrhizic Acid ,chemistry ,Intestinal Absorption ,Verapamil ,Chemistry (miscellaneous) ,Caco-2 ,Flavanones ,Monoterpenes ,Molecular Medicine ,Efflux ,Caco-2 Cells ,Liquiritin ,medicine.drug ,Drugs, Chinese Herbal - Abstract
Shaoyao-Gancao (Paeoniae Radix Alba and Glycyrrhizae Radix et Rhizoma) is a traditional Chinese drug pair widely used in decoctions for relieving pains, especially abdominal pain. We aimed to determine the intestinal absorption and interaction of three active compounds (glycyrrhizic acid, liquiritin, and paeoniflorin) in this drug pair. We investigated the transport of these compounds across intestinal epithelial cells by using the Caco-2 cell monolayer in both the apical-to-basolateral (A-B) and B-A directions. All compounds could only travel through the Caco-2 cell monolayer at a low level when the cells were treated with single component solutions. In the presence of verapamil, an inhibitor of P-glycoprotein (P-gp), the absorptive permeability (PAB) of paeoniflorin and liquiritin increased significantly (p < 0.05) and efflux ratios decreased, while the absorption of glycyrrhizic acid did not change significantly, which indicated that paeoniflorin and liquiritin might be P-gp substrates. In addition, when liquiritin and glycyrrhizic acid in Gancao extract and paeoniflorin in Shaoyao extract were examined, PAB of paeoniflorin and liquiritin were significantly higher, while glycyrrhizic acid retained the same absorption level compared to the corresponding single component solutions, which suggested that some certain ingredients in the extracts can promote the absorption of paeoniflorin and liquiritin, but not that of glycyrrhizic acid. Furthermore, compared to the results of treatment with individual extracts, treatment of cells with a mixture of the two extracts considerably increased (p < 0.05) the absorption of glycyrrhizic acid and paeoniflorin and showed no change in the absorption of liquiritin, which implied that the transport of glycyrrhizic acid and paeoniflorin is increased by some ingredients from the complementary drug in the drug pair, while that of liquiritin remains unaffected.
- Published
- 2012
30. Parameters Estimated Subsection Predicting Model for Electric Power Consumption in the Spring Festival
- Author
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Lianghui Chen, Jian Yin, and Jianhao Mai
- Subjects
Consumption (economics) ,geography ,geography.geographical_feature_category ,Computer science ,Estimation theory ,business.industry ,Prediction algorithms ,Power consumption ,Linear regression ,Spring (hydrology) ,Econometrics ,Electricity ,Electric power ,business - Abstract
Because of the Spring Festival effect, it's hard for traditional methods to predict monthly electricity consumption in January and February. This paper presents a specialized subsection-model which can better reflect the situation to solve this problem. In terms of the holiday condition, the model divides the days of the two months into two parts: the usual electricity days and holiday electricity days. In addition, an algorithm is proposed to estimate the parameters of the subsection-model according to data distribution. The data of similar situation are rare because the date of Spring Festival is different every year, the algorithm overcomes this difficulty. Experiments conducted on real dataset prove the proposed model is effective and accurate.
- Published
- 2012
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- View/download PDF
31. Optical characteristics of GaAs/AlGaAs ridge-quantum-well-wires grown by MBE on nonplanar substrates
- Author
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Qiming Wang, Yi Qian, and Lianghui Chen
- Subjects
Photoluminescence ,Band gap ,business.industry ,Chemistry ,General Chemistry ,Condensed Matter Physics ,Isotropic etching ,Blueshift ,law.invention ,Optics ,Atomic electron transition ,law ,Materials Chemistry ,Photolithography ,business ,Quantum well ,Molecular beam epitaxy - Abstract
With conventional photolithography and wet chemical etching, we have realized GaAs/AlGaAs buried ridge-quantum-well-wires (RQWWs) with vertically stacked wires in lateral arrays promising for device application, which were grown in situ by a single-step molecular beam epitaxy growth and formed at the ridge tops of mesas on nonplanar substrates. Confocal photoluminescence (CPL) and polarization-dependent photoreflectance (PR) are applied to study optical characteristics of RQWWs. Lateral bandgap modulation due to lateral variation of QW layer thickness is demonstrated not only by CPL but also by PR. As one evidence for RQWWs, a large blue shift is observed at the energy level positions for electronic transitions corresponding to quantum wells (QWs) at the ridge tops of mesas compared with those corresponding to QWs on nonpatterned areas of the same sample. The blue shift is in contradiction with the fact that the GaAs QW layers at the tops of the mesas are thicker than those on nonpatterned areas. The other evidence for RQWWs, optical anisotropy is provided by the polarization-dependent PR, which results from lateral quantum size effect existing at the tops of the mesas.
- Published
- 1993
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32. Design of Photonic Crystal Semiconductor Optical Amplifier With Polarization Independence
- Author
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Qi Aiyi, Shizhong Xie, Hongling Peng, Lianghui Chen, Wanhua Zheng, Hongwei Qu, and Yejin Zhang
- Subjects
Optical amplifier ,Materials science ,business.industry ,Physics::Optics ,chemistry.chemical_element ,Optical polarization ,Polarization (waves) ,Slow light ,Waveguide (optics) ,Atomic and Molecular Physics, and Optics ,Thulium ,Optics ,chemistry ,Optoelectronics ,Photonics ,business ,Photonic crystal - Abstract
Slow-light effects in photonic crystal (PC) waveguides can enhance light-mater interaction near the photonic band edge, which can be used to design a short cavity length semiconductor optical amplifier (SOA). In this paper, a novel SOA based on slow-light effects in PC waveguides (PCSOA) is presented. To realize the amplification of the optical signal with polarization independence, a PCSOA is designed with a compensated structure. The cascaded structure leads to a balanced amplification to the TE and TM polarized light.
- Published
- 2010
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33. Broadband short-range surface plasmon structures for absorption enhancement in organic photovoltaics
- Author
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Qiaoqiang Gan, Wenli Bai, Lianghui Chen, Zakya H. Kafafi, Filbert J. Bartoli, and Guofeng Song
- Subjects
Materials science ,Organic solar cell ,business.industry ,Surface plasmon ,Physics::Optics ,Heterojunction ,Surface plasmon polariton ,Atomic and Molecular Physics, and Optics ,Polymer solar cell ,Optics ,Photovoltaics ,Polariton ,Optoelectronics ,Plasmonic solar cell ,business ,Absorption (electromagnetic radiation) ,Plasmon ,Localized surface plasmon - Abstract
We theoretically demonstrate a polarization-independent nanopatterned ultra-thin metallic structure supporting short-range surface plasmon polariton (SRSPP) modes to improve the performance of organic solar cells. The physical mechanism and the mode distribution of the SRSPP excited in the cell device were analyzed, and reveal that the SRSPP-assisted broadband absorption enhancement peak could be tuned by tailoring the parameters of the nanopatterned metallic structure. Three-dimensional finite-difference time domain calculations show that this plasmonic structure can enhance the optical absorption of polymer-based photovoltaics by 39% to 112%, depending on the nature of the active layer (corresponding to an enhancement in short-circuit current density by 47% to 130%). These results are promising for the design of organic photovoltaics with enhanced performance.
- Published
- 2010
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- View/download PDF
34. Demonstration of high efficient tunable lasing with one photonic crystal W1 waveguide
- Author
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Anjin Liu, Wenjun Zhou, Wanhua Zheng, Mingxin Xing, Wei Chen, Hailing Wang, and Lianghui Chen
- Subjects
Waveguide lasers ,Materials science ,business.industry ,Physics::Optics ,Laser ,Waveguide (optics) ,Semiconductor laser theory ,law.invention ,Optics ,Photonic crystal waveguides ,law ,Optoelectronics ,Spontaneous emission ,business ,Lasing threshold ,Photonic crystal - Abstract
High efficient tunable edge emitting microlaser was realized with W1 photonic crystal waveguide. Light from micocavity transferred into waveguide directly by mode transforming. A tunable range of 57 nm was obtained experimentally.
- Published
- 2009
- Full Text
- View/download PDF
35. The fabrication of a 128×128 solar-blind AlGaN p-i-n back-illuminated ultraviolet photodetector array
- Author
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Lianghui Chen, Ming Chong, Tingjing Yan, Shuang Zhang, and Degang Zhao
- Subjects
Photocurrent ,Materials science ,business.industry ,Photodetector ,Biasing ,Heterojunction ,medicine.disease_cause ,Responsivity ,Optics ,medicine ,Sapphire ,Optoelectronics ,business ,Ultraviolet ,Dark current - Abstract
128×128 pixels AlGaN solar blind ultraviolet photodetector arrays have been designed and fabricated. The diameter of each pixel is 44μm with a 50μm pitch. They are photosensitive in the waveband of 225~255nm, with the peak sensitivity at 246nm. The back-illuminated p-i-n heterojunction structure has been grown on transparent sapphire substrate using MOCVD, the aluminum composition of Al x Ga 1-x N n-type window layer was 71%, and the alloy composition of the unintentionally doped (UID) absorber layer was 52%. The dark current measured at a bias voltage close to zero is 27 pA, and the photocurrent is 2.7 nA at the incidence optical power of 0.12 mW in a wavelength of 246 nm, corresponding to a peak responsivity of 23mA/W.
- Published
- 2009
- Full Text
- View/download PDF
36. High polarization single dipole mode photonic crystal microlaser
- Author
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Wenjun Zhou, Anjin Liu, Lianghui Chen, Mingxin Xing, Wei Chen, and Wanhua Zheng
- Subjects
Materials science ,Extinction ratio ,business.industry ,Single-mode optical fiber ,Physics::Optics ,Polarization (waves) ,Semiconductor laser theory ,Optics ,Lattice (order) ,Q factor ,Optoelectronics ,Physics::Atomic Physics ,business ,Lasing threshold ,Photonic crystal - Abstract
A photonic crystal microlaser with elongate lattice was fabricated. Lasing action of single mode, y-dipole mode, was observed. With this mode, a high polarization extinction ratio of 51:1 was obtained.
- Published
- 2009
- Full Text
- View/download PDF
37. Integration of a photonic crystal polarization beam splitter and waveguide bend
- Author
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Wanhua Zheng, Steven G. Johnson, Wenjun Zhou, Lianghui Chen, Gang Ren, Mingxin Xing, and Wei Chen
- Subjects
Waveguide (electromagnetism) ,Materials science ,business.industry ,Photonic integrated circuit ,Finite-difference time-domain method ,Physics::Optics ,Integrated circuit ,Coupled mode theory ,Yablonovite ,Atomic and Molecular Physics, and Optics ,law.invention ,Optics ,law ,Optoelectronics ,business ,Refractive index ,Photonic crystal - Abstract
In this work, we present the design of an integrated photonic-crystal polarization beam splitter (PC-PBS) and a low-loss photonic-crystal 60 waveguide bend. Firstly, the modal properties of the PC-PBS and the mechanism of the low-loss waveguide bend are investigated by the two-dimensional finite-difference time-domain (FDTD) method, and then the integration of the two devices is studied. It shows that, although the individual devices perform well separately, the performance of the integrated circuit is poor due to the multi-mode property of the PC-PBS. By introducing deformed airhole structures, a single-mode PC-PBS is proposed, which significantly enhance the performance of the circuit with the extinction ratios remaining above 20dB for both transverse-electric (TE) and transverse-magnetic (TM) polarizations. Both the specific result and the general idea of integration design are promising in the photonic crystal integrated circuits in the future. (C) 2009 Optical Society of America
- Published
- 2009
38. High efficient and tunable edge emitting microlaser on photonic crystal slab
- Author
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Wenjun Zhou, Mingxin Xing, Hailing Wang, Anjin Liu, Wei Chen, Lianghui Chen, and Wanhua Zheng
- Subjects
Waveguide lasers ,Condensed Matter::Quantum Gases ,Waveguide (electromagnetism) ,Range (particle radiation) ,Materials science ,business.industry ,Astrophysics::High Energy Astrophysical Phenomena ,Physics::Optics ,Resonance ,Edge (geometry) ,Waveguide (optics) ,Optics ,Quantum dot laser ,Slab ,Optoelectronics ,business ,Photonic crystal ,Line (formation) - Abstract
Tunable edge emitting microlaser was realized with a line defect waveguide, in which the radii of holes adjacent to the defect were varied gradually. A tunable range of 57 nm was obtained experimentally.
- Published
- 2009
- Full Text
- View/download PDF
39. Single dipole mode photonic crystal laser on InGaAsP/InP QW waveguide slab
- Author
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Ke Wang, Xiaoyu Du, Lianghui Chen, Gang Ren, Minxin Xing, and Wanhua Zheng
- Subjects
Materials science ,business.industry ,Single-mode optical fiber ,Physics::Optics ,Laser ,Crystallographic defect ,Molecular physics ,law.invention ,Dipole ,Optics ,law ,business ,Lasing threshold ,Waveguide ,Quantum well ,Photonic crystal - Abstract
Single point defect microcavity possesses only the degenerate dipole modes under certain photonic crystal structure parameters. By deforming lattice structure, the degeneracy of the dipole modes has been broken. Theoretical simulation shows the large splitting of 65nm between the splitted x-mode and y-mode, approximate to the luminescent gain spectrum, which benefits for the single mode lasing. Experimentally the single dipole mode lasing, y-mode, is achieved in the deformed microcavity.
- Published
- 2008
- Full Text
- View/download PDF
40. A Novel Single-Mode High-Power Low-Divergence-Angle Photonic Crystal VCSEL
- Author
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Wenjun Zhou, Hongwei Qu, Wei Chen, Anjin Liu, Yejin Zhang, Mingxin Xing, Lianghui Chen, and Wanhua Zheng
- Subjects
Optical fiber ,Materials science ,business.industry ,Single-mode optical fiber ,law.invention ,Semiconductor laser theory ,Gallium arsenide ,Vertical-cavity surface-emitting laser ,chemistry.chemical_compound ,Optics ,chemistry ,law ,Optoelectronics ,Photolithography ,business ,Photonic-crystal fiber ,Photonic crystal - Abstract
A novel GaAs-based 850 nm photonic crystal VCSEL is demonstrated. Output power of 3.5 mW with a side mode suppression ratio of 30 dB is observed. The divergence angle is 4.2° at 20 mA.
- Published
- 2008
- Full Text
- View/download PDF
41. Amphiphilic core–shell nanocomposite particles with magnetic-cores for enhanced magnetic resonance
- Author
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Pei Li, Dechao Niu, Lianghui Chen, and Cheng Hao Lee
- Subjects
Nanocomposite ,Materials science ,medicine.diagnostic_test ,Biomedical Engineering ,Pharmaceutical Science ,Medicine (miscellaneous) ,Bioengineering ,Nanotechnology ,Magnetic resonance imaging ,Core shell ,Amphiphile ,medicine ,Molecular Medicine ,General Materials Science - Published
- 2016
- Full Text
- View/download PDF
42. Mode control by lattice deforming in InGaAsP/InP photonic crystal laser
- Author
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Xiaoyu Du, Ke Wang, Lianghui Chen, Wanhua Zheng, Gang Ren, Kengo Nozaki, Toshihiko Baba, and Minxin Xing
- Subjects
Materials science ,business.industry ,Single-mode optical fiber ,Physics::Optics ,Crystal structure ,Laser ,law.invention ,Semiconductor laser theory ,chemistry.chemical_compound ,chemistry ,law ,Lattice (order) ,Indium phosphide ,Optoelectronics ,business ,Lasing threshold ,Photonic crystal - Abstract
The dipole mode in point defect photonic crystal shows the characteristics of nondegenerate by deforming lattice structure. Lasing action with single mode, y-mode, is obtained in the elongated point defect cavity in our experiment.
- Published
- 2007
- Full Text
- View/download PDF
43. Direct wafer bonding technology employing vacuum-cavity pre-bonding
- Author
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Guorong He, Lianghui Chen, Guohua Yang, and Wanhua Zheng
- Subjects
Materials science ,Silicon ,Wafer bonding ,business.industry ,chemistry.chemical_element ,Semiconductor device ,Surface energy ,chemistry.chemical_compound ,chemistry ,Anodic bonding ,Ultimate tensile strength ,Indium phosphide ,Optoelectronics ,Wafer ,business - Abstract
A novel low temperature direct wafer bonding technology employing vacuum-cavity pre-bonding is proposed and applied in bonding of InGaAs/Si couple wafers under 300 degrees C and InP/GaAs couple wafers under 350 degrees C. Aligning accuracy of 0.5 mu m is achieved. During wafer bonding process the pressure on the couple wafers is 10MPa. The interface energy is sufficiently high to allow thinning of the wafers down from 350um to about 100um. And the tensile strength test indicates the bonding energy of bonded samples is about equal to the bonded samples at 550 degrees C.
- Published
- 2006
- Full Text
- View/download PDF
44. Hybrid Successive Interference Cancellation Multi-user Detector for WCDMA Uplink System
- Author
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Hanying Hu and Lianghui Chen
- Subjects
Single antenna interference cancellation ,Computer science ,Code division multiple access ,Real-time computing ,Telecommunications link ,Electronic engineering ,Bit error rate ,Multiuser detection ,Processing delay ,Computer Science::Information Theory ,Communication channel ,Rayleigh fading - Abstract
Successive interference cancellation (SIC) and parallel interference cancellation (PIC) are promising nonlinear multi-user detection techniques for code division multiple access (CDMA). It has previously been shown that PIC has the high bit error rate (BER) diffuseness of weak users and large hardware logic resources consumption and SIC suffers mightily from a high processing delay and ranks the sequence of received users frequently. The paper presents the hybrid SIC (HSIC) algorithm that mitigates the above disadvantages from a point of view of tradeoff between the realization and the performance. Simulation results show that the performance of HSIC is close to the SIC and is superior to the PIC for the WCDMA uplink system under the flat Rayleigh fading channel
- Published
- 2006
- Full Text
- View/download PDF
45. Leakage current analysis in AlGaInP/GaInP multi-quantum well lasers by the electrical derivative method
- Author
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Yun Xu, Liang Guo, Lianghui Chen, Yuzhang Li, Qing Cao, Qiaoqiang Gan, and Guofeng Song
- Subjects
Materials science ,business.industry ,Physics::Optics ,Laser ,law.invention ,Semiconductor laser theory ,Indium gallium phosphide ,Secondary ion mass spectrometry ,chemistry.chemical_compound ,Optics ,chemistry ,law ,Optoelectronics ,Rectangular potential barrier ,Metalorganic vapour phase epitaxy ,business ,Quantum well ,Diode - Abstract
In AlGaInP/GaInP multi-quantum well (MQW) lasers, the electron leakage current is a much more serious problem than that in laser diodes with longer wavelength. To further improve the output performance, the leakage current should be analyzed. In this letter, the temperature dependence of electrical derivative characteristics in AlGaInP/GaInP multi-quantum well lasers was measured, and the potential barrier for electron leakage was obtained. With the help of secondary ion mass spectroscopy (SIMS) measurement, theoretical analysis of the potential barrier was presented and compared with the measurement result. The influence of p-cladding doping level and doping profile on the potential barrier was discussed, and this can be helpful in metalorganic chemical vapor deposition (MOCVD) growth.
- Published
- 2005
- Full Text
- View/download PDF
46. High-output very small aperture laser and its near-field distribution properties
- Author
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Qiaoqiang Gan, Suofeng Song, and Lianghui Chen
- Subjects
Fabrication ,Materials science ,business.industry ,Aperture ,Near-field optics ,Near and far field ,Laser ,law.invention ,Power (physics) ,Semiconductor laser theory ,Optics ,law ,Laser power scaling ,business - Abstract
A Very-Small-Aperture Laser with a 250X500 nm 2 aperture has been created on a 650nm edge emitting LD. The highest far-field output power is 1.9mW and the power per unit emission area is about 15mW/μm2. The special fabrication process and high output power mechanism are demonstrated respectively. The near-field distribution properties are also analyzed theoretically and experimentally.
- Published
- 2005
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47. Performance analysis of very-small-aperture lasers
- Author
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Yuan Zhong, Qiaoqiang Gan, Xiaopeng Zhu, Qing Cao, Guohua Yang, Xuejian Pan, Guofeng Song, Yun Xu, Jianxia Gao, and Lianghui Chen
- Subjects
Distributed feedback laser ,Materials science ,Laser diode ,business.industry ,Physics::Optics ,Laser pumping ,Laser ,Atomic and Molecular Physics, and Optics ,law.invention ,Vertical-cavity surface-emitting laser ,Optics ,Laser diode rate equations ,law ,Diode-pumped solid-state laser ,Physics::Atomic Physics ,Laser power scaling ,business - Abstract
The fabrication of very-small-aperture lasers is demonstrated, and their performance is analyzed. Because of strong optical feedback caused by a gold film on the front facet of the laser, its behavior changes: The threshold current decreases, the density of light inside the laser diode and the redshift effect of the spectra are enhanced, and the laser diode's lifetime is shorter than that of common laser diodes with large driving current. (c) 2005 Optical Society of America
- Published
- 2005
48. Theoretical analysis of the bandgap for the intermixed GaInP/AlGaInP quantum wells
- Author
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Lianghui Chen, Guofeng Song, Xiaopeng Zhu, Yuzhang Li, Qing Cao, Liang Guo, and Yun Xu
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Condensed Matter::Quantum Gases ,Valence (chemistry) ,Materials science ,Condensed matter physics ,Band gap ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Indium gallium phosphide ,Condensed Matter::Materials Science ,symbols.namesake ,chemistry.chemical_compound ,chemistry ,Gallium phosphide ,symbols ,Indium phosphide ,Hamiltonian (quantum mechanics) ,Electronic band structure ,Quantum well - Abstract
Compositional distribution of the quantum well and barrier after quantum well intermixing for GaInP/AlGaInP system was theoretically analyzed on the basis of atom diffusion law. With the compositional distribution result, the valence subband structure of the intermixed quantum well was calculated on the basis of 6x6 Luttinger-Kohn Hamiltonian, including spin-orbit splitting effects. TO get more accurate results in the calculation, a full 6-band problem was solved without axial approximation, which had been widely used in the Luttinger-Kohn model to simplify the computational efforts, since there was a strong warping in the GaInP valence band. At last, the bandgap energy of the intermixed quantum well was obtained and the calculation result is of much importance in the analysis of quantum well intermixing experiments.
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- 2005
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49. Calculation of valence subband structures for strained GaInP/AlGaInP quantum wells without axial approximation
- Author
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Xiaopeng Zhu, Lianghui Chen, Yuzhang Li, Guofeng Song, Qing Cao, Liang Guo, Yun Xu, and Qiaoqiang Gan
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Materials science ,Valence (chemistry) ,Condensed matter physics ,Finite difference method ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Indium gallium phosphide ,Condensed Matter::Materials Science ,chemistry.chemical_compound ,symbols.namesake ,chemistry ,Gallium phosphide ,symbols ,Indium phosphide ,Direct and indirect band gaps ,Hamiltonian (quantum mechanics) ,Quantum well - Abstract
Usually in the calculation of valence subband structure for III-V direct bandgap material, axial approximation had been used in the Luttinger-Kohn model to simplify the computational efforts. In this letter, the valence subband structure for the GaInP/AlGaInP strained and lattice-matched quantum wells was calculated without axial approximation, on the basis of 6x6 Luttinger-Kohn Hamiltonian including strain and spin-orbit splitting effects. The numerical simulation results were presented with help of the finite-difference methods. The calculation results with/without axial approximation were compared and the effect of axial approximation on the valence subband structure was discussed in detail. The results indicated that there was a strong warping in the GaInP valence band, and axial approximation can lead to an error when k was not equal to zero, especially for compressively strained and lattice-matched GaInP/AlGaInP quantum wells.
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- 2005
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50. Liquid nitrogen flowrate alarm system for MBE
- Author
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Yongwei Sun, Shuying Li, Yun Xu, Lianghui Chen, and Haiqiao Ni
- Subjects
ALARM ,Impurity ,Chemistry ,business.industry ,Analytical chemistry ,chemistry.chemical_element ,Liquid nitrogen ,Process engineering ,business ,Nitrogen ,Volumetric flow rate ,Molecular beam epitaxy - Abstract
Liquid nitrogen is very important for MBE system. Most MBE systems use the liquid nitrogen to absorb the impurity molecules. If MBE cryoshroud is lack of liquid nitrogen, the pressure of the growth chamber will grow. This will affect the film quality. But too much liquid nitrogen is a waste. We have developed a liquid nitrogen flowrate alarm system to monitor the liquid nitrogen status in MBE cryoshroud. In this method, a temperature sensor is placed at the end of the cryoshroud. The temperature varies with changing of the liquid nitrogen status in cryoshroud. If the liquid nitrogen level in the cryoshroud is too low or too high, the LNFA will send out an alarm to warn the user to adjust the liquid nitrogen flowrate. In our experiments, we found this method works well, and the temperature responds sensitively. With the help of this system, people can view the liquid nitrogen status of the entire growth process. Compare with other method. it is very cheap.
- Published
- 2004
- Full Text
- View/download PDF
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