Epitaxial Growth of Strain-Induced Ferromagnetic LaCoO3 Thin Films by Simple Sol–Gel Technique

Haifeng Liu,Yuqiao Guo,Ruishi Xie,Guohua Ma 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.3

LaCoO3 (LCO) epitaxial films were grown on (001) LaAlO3 (LAO) substrates by the simple sol– gel technique. X-ray diffraction (XRD) and the cross-section transmission electron microscope (TEM) measurements indicate that single-phase (001) oriented LCO epitaxial films with biaxial compressive strain and elongated distortion of CoO6 octahedrons were grown on (001) LAO successfully. The epitaxial relationship between the LCO film and the LAO substrate is confirmed to be (001)LCO||(001)LAO and [100]LCO||[100]LAO. It is also found that LCO grown on LAO has a larger mean Co–O bond length and unit-cell size, compared with those of polycrystalline film. In addition, the magnetic characterization shows that LCO epitaxial film exhibits an obvious ferromagnetic (FM) transition at TC ~ 85 K, which is different from the nonmagnetic ground state of polycrystalline LCO. Combined with the structural analyses, it reveals that the strain-induced ferromagnetism observed in LCO epitaxial film originates from an increase of the mean Co–O bond length and a suppression of the CoO6 octahedral rotations, which can stabilize higher spin state of Co3+ by a decrease of the eg~t2g gap energy.

Theoretically Exploring the Phase Precision in a Noisy Mach-Zehnder Interferometer

Xie Duan,Chen Haifeng 한국물리학회 2017 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.70 No.12

This paper presents the phase precision of a Mach-Zehnder interferometer in the presence of two types of quantum noise. Under the influence of amplitude-damping noise, the precisions of three input cases will gradually decrease and be less than the standard quantum limit. When the quantum states are influenced by bit-phase flip, the precisions for inputs of a coherent state and a squeezed vacuum state and the precision of spin squeezing state decrease at first and then increase with increasing (parameter characterizing the noise strength) from 0 to 1. Comparing the rates at which the precisions decrease, we found that the precision of the spin squeezing state decreased faster than those of the other two cases in most instances.

Quantum Noise on the Coherent-transport Protocol for Clock Synchronization

Xie Duan,Chen Haifeng 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.68 No.4

The paper presents the synchronization accuracies of the coherent-transport protocol in the presence of quantum noise. Under the influence of bit flip noise, the accuracy will reduce to the standard quantum limit. When influenced by phase flip and amplitude damping, the accuracies are lower than the standard quantum limit in most cases. By comparison to the performance of the onequbit transport protocol and the entangled-states transport protocol, we found the accuracy of the coherent-transport protocol to be lower than the accuracies of the other two protocols in the presence of phase flip and amplitude damping.

Preparation and Microwave Absorption Properties of the Fe/TiO2/Al2O3 Composites

Yun Li,Haifeng Cheng,Nannan Wang,Shen Zhou,Dongjin Xie,Tingting Li 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.11

To reduce the imbalance of impedance matching between the magnetic metal nanowires and free space, Fe/TiO2 core/shell nanowire arrays with different diameters were fabricated in the templates of anodic aluminum oxide membranes by electrodeposition. The influences of the microstructure on the microwave absorption properties of the Fe/TiO2/Al2O3 composites were studied by the transmission/reflection waveguide method. It was demonstrated experimentally that both the interfacial polarization and the diameter of the Fe/TiO2 core/shell nanowires have critical effects on the microwave absorption properties. We also investigated the angle dependence of the microwave absorption properties. Due to the interfacial polarization and associated relaxation, the Fe/TiO2/Al2O3 composites exhibited optimal microwave absorption properties when microwave propagation direction was accordant with the axis of the nanowires. Finally, we managed to obtain an optimal reflection loss of below -10 dB (90% absorption) over 10.2–14.8 GHz, with a thickness of 3.0mm and the minimum value of -39.4 dB at 11.7 GHz.

Copper Phthalocyanine Functionalized Polystyrene Superfine Fibers for the Photodegradation of Methyl Orange

Kexin Peng,Jiankui Guo,Haifeng Chen,Mali Xie,Xi Zhang,Xudong Huang,Guiying Xing,Linjun Shao,Chenze Qi 한국섬유공학회 2023 Fibers and polymers Vol.24 No.11

In this paper, copper phthalocyanine and polystyrene composite superfine fibers were readily prepared by electrospinning technology. After treating these composite fibers with paraformaldehyde in concentrated H2SO4 solution, the copper phthalocyanine molecules were covalently bonded to the polystyrene molecules. Meanwhile, the polystyrene molecules in the fibers were cross-linked to endow these fibers with excellent solvent resistance. The photocatalytic performance of this novel fibrous catalyst was evaluated by photodegradation of methyl orange in the presence of H2O2. The effects of light source, H2O2 dosage, catalyst loading, and temperature on the fiber catalyzed photodegradation of methyl orange were carefully studied. The photodegradation percentage of methyl orange in aqueous solution was up to ~ 97% under optimized reaction conditions. At last, this fibrous catalyst was readily recovered by simple filtration and reused for three times with satisfied photodegradation activities. In all, we have developed a facile way to prepare copper phthalocyanine functionalized polystyrene superfine fibers with excellent photocatalytic performance.

NMAAP1 Expressed in BCG-Activated Macrophage Promotes M1 Macrophage Polarization

Liu, Qihui,Tian, Yuan,Zhao, Xiangfeng,Jing, Haifeng,Xie, Qi,Li, Peng,Li, Dong,Yan, Dongmei,Zhu, Xun Korean Society for Molecular and Cellular Biology 2015 Molecules and cells Vol.38 No.10

Macrophages are divided into two subpopulations: classically activated macrophages (M1) and alternatively activated macrophages (M2). BCG (Bacilli Calmette-$Gu{\acute{e}}rin$) activates disabled $na{\ddot{i}}ve$ macrophages to M1 macrophages, which act as inflammatory, microbicidal and tumoricidal cells through cell-cell contact and/or the release of soluble factors. Various transcription factors and signaling pathways are involved in the regulation of macrophage activation and polarization. We discovered that BCG-activated macrophages (BAM) expressed a new molecule, and we named it Novel Macrophage Activated Associated Protein 1 (NMAAP1). 1 The current study found that the overexpression of NMAAP1 in macrophages results in M1 polarization with increased expression levels of M1 genes, such as inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-${\alpha}$), Interleukin 6 (IL-6), Interleukin 12 (IL-12), Monocyte chemoattractant protein-1 (MCP-1) and Interleukin-1 beta (IL-$1{\beta}$), and decreased expression of some M2 genes, such as Kruppel-like factor 4 (KLF4) and suppressor of cytokine signaling 1 (SOCS1), but not other M2 genes, including arginase-1 (Arg-1), Interleukin (IL-10), transforming growth factor beta (TGF-${\beta}$) and found in inflammatory zone 1 (Fizz1). Moreover, NMAAP1 overexpression in the RAW264.7 cell line increased cytotoxicity against MCA207 tumor cells, which depends on increased inflammatory cytokines rather than cell-cell contact. NMAAP1 also substantially enhanced the phagocytic ability of macrophages, which implies that NMAAP1 promoted macrophage adhesive and clearance activities. Our results indicate that NMAAP1 is an essential molecule that modulates macrophages phenotype and plays an important role in macrophage tumoricidal functions.

Shear bond strength of zirconia to resin: The effects of specimen preparation and loading procedure

Bingzhuo Chen,Lu Yang,Zhicen Lu,Hongliang Meng,Xinyi Wu,Chen Chen,Haifeng Xie 대한치과보철학회 2019 The Journal of Advanced Prosthodontics Vol.11 No.6

PURPOSE. Shear bond strength (SBS) test is the most commonly used method for evaluating resin bond strength of zirconia, but SBS results vary among different studies even when evaluating the same bonding strategy. The purpose of this study was to promote standardization of the SBS test in evaluating zirconia ceramic bonding and to investigate factors that may affect the SBS value of a zirconia/resin cement/composite resin bonding specimen. MATERIALS AND METHODS. The zirconia/resin cement/composite resin bonding specimens were used to simulate loading with a shear force by the three-dimensional finite element (3D FE) modeling, in which stress distribution under uniform/non-uniform load, and different resin cement thickness and different elastic modulus of resin composite were analyzed. In vitro SBS test was also performed to validate the results of 3D FE analysis. RESULTS. The loading flat width was an important affecting factor. 3D FE analysis also showed that differences in resin cement layer thickness and resin composite would lead to the variations of stress accumulation area. The SBS test result showed that the load for preparing a SBS specimen is negatively correlated with the resin cement thickness and positively correlated with SBS values. CONCLUSION. When preparing a SBS specimen for evaluating bond performance, the load flat width, the load applied during cementation, and the different composite resins used affect the SBS results and therefore should be standardized.

A facile technique to prepare cross-linked enzyme aggregates using p-benzoquinone as cross-linking agent

Anming Wang,Fangkai Zhang,Feifei Chen,Meizhang Wang,Haifeng Li,Zhaowu Zeng,Tian Xie,Zhenming Chen 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.4

To obtain robust and thermo-stable enzyme aggregates, p-benzoquinone was used as cross-linker and bovine serum albumin (BSA) as crowding macromolecules to prepare cross-linked enzyme aggregates (CLEAs) of lipase. Effects of cross-linking time and cross-linker content on the activity, thermal stability and characteristics of enzyme aggregates were examined carefully. It was observed that when the content of p_benzoquinone was 5 mM and amount of BSA was 125% of that of lipase (w/w), the specific activity of cross-linked co-aggregates of lipase and BSA was 79.8 U mg^−1, 2.44-fold of that of cross-linked enzyme aggregates of lipase without BSA. Moreover, after heat treatment for 96 h at 50℃ , the CLEAs prepared with this facile routine kept 75.18% of their initial activity, 5.01-fold more than that of the just CLEAs using glutaraldehyde. Furthermore, BSA macromolecules in lipase CLEAs enhanced the catalytic efficiency of free and just lipase CLEAs without BSA by 1.45 and 2.83 times, respectively. The proposed crosslinking technique would rank among the potential strategies for efficiently preparing robust and thermo-stable enzyme aggregates.

NMAAP1 Expressed in BCG-Activated Macrophage Promotes M1 Macrophage Polarization

Qihui Liu,Xun Zhu,Yuan Tian,Xiangfeng Zhao,Haifeng Jing,Qi Xie,Peng Li,Dong Li,Dongmei Yan 한국분자세포생물학회 2015 Molecules and cells Vol.38 No.10

Macrophages are divided into two subpopulations: classically activated macrophages (M1) and alternatively activated macrophages (M2). BCG (Bacilli Calmette-Guérin) activates disabled naïve macrophages to M1 macrophages, which act as inflammatory, microbicidal and tumoricidal cells through cell-cell contact and/or the release of soluble factors. Various transcription factors and signaling pathways are involved in the regulation of macrophage activation and polarization. We discovered that BCG-activated macrophages (BAM) expressed a new molecule, and we named it Novel Macrophage Activated Associated Protein 1 (NMAAP1). 1 The current study found that the overexpression of NMAAP1 in macrophages results in M1 polarization with increased expression levels of M1 genes, such as inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-α), Interleukin 6 (IL-6), Interleukin 12 (IL-12), Monocyte chemoattractant protein-1 (MCP-1) and Interleukin-1 beta (IL-1β), and decreased expression of some M2 genes, such as Kruppel-like factor 4 (KLF4) and suppressor of cytokine signaling 1 (SOCS1), but not other M2 genes, including arginase-1 (Arg-1), Interleukin (IL-10), transforming growth factor beta (TGF-β) and found in inflammatory zone 1 (Fizz1). Moreover, NMAAP1 overexpression in the RAW264.7 cell line increased cytotoxicity against MCA207 tumor cells, which depends on increased inflammatory cytokines rather than cell-cell contact. NMAAP1 also substantially enhanced the phagocytic ability of macrophages, which implies that NMAAP1 promoted macrophage adhesive and clearance activities. Our results indicate that NMAAP1 is an essential molecule that modulates macrophages phenotype and plays an important role in macrophage tumoricidal functions.

Choice of resin cement shades for a high-translucency zirconia product to mask dark, discolored or metal substrates

Shiqi Dai,Chen Chen,Mo Tang,Ying Chen,Lu Yang,Feng He,Bingzhuo Chen,Haifeng Xie 대한치과보철학회 2019 The Journal of Advanced Prosthodontics Vol.11 No.5

PURPOSE. The aim was to study the masking ability of high-translucency monolithic zirconia and provide guidance in selecting resin luting cements in order to mask discolored substrates. MATERIALS AND METHODS. 160 high-translucency zirconia specimens were divided into 32 groups depending on their thickness and shades. Using five shades of try-in paste, the specimens were luted onto the sub strates (Co-Cr, precious-metal, opaque porcelain-sintered Co-Cr, opaque porcelain-sintered precious-metal, and 5M3-shade zirconia). All CIELAB color parameters were measured and statistically analyzed. RESULTS. Zirconia shade and thickness and try-in paste shade affected CIELAB color parameters (P=.000) in different substrates groups, and there were interactions among these factors (P=.000). All five try-in paste shades can be chosen to achieve ΔE values of zirconia with 1.2 - 1.5 mm for masking dark-tooth-like 5M3-shade and zirconia with 1.5 mm for masking precious-metal groups < 2.6. Only suitable try-in paste shades were used, can ΔE values that less than 2.6 be achieved when applied translucent monolithic zirconia with 0.7-1.0 mm for masking dark-tooth-like 5M3-shade and zirconia with 0.7 - 1.2 mm for masking precious-metal groups. CONCLUSION. Choosing suitable resin cement shades is necessary for high-translucency monolithic zirconia to achieve ideal masking ability (ΔE < 2.6) on the dark-tooth.