Investigation on the morphology of hierarchical mesoporous ZSM-5 zeolite prepared by the CO2-in-water microemulsion method

Chunlei Wang,Juntao Yan,Jianfen Li,Jianmin Sun 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.9

A series of hierarchical mesoporous ZSM-5 zeolites with different morphology were successfully syn-thesized by the CO2-in-water microemulsion method, and mesoporosity was formed without organotemplate. The dif-ferent synthesis conditions, including silica alumina molar ratio, stirring time and compressed CO2 pressure, were sys-tematically investigated to discuss the influence of these conditions on the morphology of ZSM-5 zeolite. The resultingsamples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), inductively coupledplasma (ICP) and nitrogen adsorption-desorption measurement. XRD results indicated that compressed CO2 route forthe synthesis of MFI zeolites had a fast crystallization rate and good crystallinity. SEM images showed that the ZSM-5hierarchical mesoporous ZSM-5 zeolite had a uniform chain-like crystal morphology, whereas silicalite-1 displayed amonodisperse crystal morphology. In addition, the nitrogen adsorption-desorption measurement provided sufficientevidence for the presence of hierarchical mesopores in ZSM-5 zeolite.

Non-linear magneto-optical properties in sputtered and epitaxial ultrathin films

Chunlei Gao,Qing-Yuan Jin,Bin Ma,Jun Ye,Yang Ren 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.44 No.32

The nonlinear magneto-optical properties of polycrystalline Co lms and single crystalline Fe lms epitaxially grown on Co(001) substrate are studied ex situ and in situ, respectively, by the magnetization-induced second harmonic generation (MSHG) technique. The magnetic contrast in MSHG intensity can be clearly distinguished for the cobalt lms, and dependence of the magnetic second harmonic intensity on the thickness of the magnetic lm and a nonmagnetic covering is found, which is the result of the combined contributions of the magnetic surface and interfaces. A giant nonlinear Kerr rotation of more than 2 degrees, being at least an order of magnitude larger than its linear one, is achieved for the polycrystalline Co lms. By using the MSHG method, the magnetic phase transitions of the ultrathin epitaxial Fe lms at a thickness of about 4 ML and 11 ML can be successfully observed, showing sensitivity to the lm structure and magnetic orders. If combined with the magneto-optical Kerr eect (MOKE), more information could be obtained.

Automatic Pest Detection Implemented in Robotics in Green House

Chunlei Xia,Bu-Keun Chung,Jang-Myung Lee,Tae-Soo Chon 한국응용곤충학회 2010 한국응용곤충학회 학술대회논문집 Vol.2010 No.05

Accurate estimation of pest density is a prerequisite in achieving efficient pest management. An automatic pest detection system with image processing was installed on a robot to recognize brown marmorated stink bug (Halyomorphahalys) on leaves of paprika(Capsicumannuumvar.angulosum). The shape of pest was recognized and subsequently the robot arm was moved toward the leaves to spray pesticides. The detection system was efficient along with increasing population densities increased. The robot with image processing system was useful for estimating population densities in spatial and temporal domain efficiently.

Ionic liquid gating control of magnetic anisotropy in Ni0.81Fe0.19 thin films

Chunlei Li,Shishun Zhao,Ziyao Zhou,Bin Peng,Zhongqiang Hu,Ming Liu 한국물리학회 2020 Current Applied Physics Vol.20 No.7

Voltage control magnetism is one of the most energy efficient pathway towards magnetoelectric (ME) device. Ionic liquid gating (ILG) method has already shown impressive manipulation power at the IL/electrode interface to influence the structure, orbital as well as spin of the electrode materials. As key material in anisotropy magnetoresistance sensor and spin valve heterostructure, the permalloy Ni0.81Fe0.19 was utilized as the electrode to investigate the ILG induced magnetic anisotropy change. In this work, we realized magnetic anisotropy control in Au/[DEME]+[TFSI]-/Ni0.81Fe0.19 (2.5 nm)/Ta heterostructure via ILG caused electrostatic doping. This is evidenced in situ reversible ferromagnetic field (Hr) shift with electron spin resonance (ESR) spectrometer. Aiming at the question whether the charge accumulation at the ionic liquid interface is the main control mechanism at low voltage, we carefully tested the relationship between the change of resonance field and the amount of surface charge. It was found that these two had a good linear relationship between −1 V and +1 V. Defining the linear parameter as A whose value is 28.7 mT m2/Col. Unlike previously reported chemical regulation of Co, this article used ionic liquids to physically regulate NiFe, which has not been studied in the previous ionic liquid regulation. And NiFe has a narrower resonance line width for easy reference to microwave devices. In addition, It also has a stronger ferromagnetic signal than Co, which can be more easily detected as a sensor device. Therefore, this system is more promising. The ILG control NiFe may lead to a new kind of magnetoelectric sensor devices and path a new way to low energy consumption spintronics.

Mitigating the Surface Urban Heat Island: Mechanism Study and Sensitivity Analysis

Chunlei MENG 한국기상학회 2017 Asia-Pacific Journal of Atmospheric Sciences Vol.53 No.3

In a surface urban heat island (SUHI), the urban land surface temperature (LST) is usually higher than the temperature of the surrounding rural areas due to human activities and surface characteristics. Because a SUHI has many adverse impacts on urban environment and human health, SUHI mitigation strategies are very important. This paper investigates the mechanism of a SUHI based on the basic physical laws that control the formation of a SUHI; five mitigation strategies are proposed, namely: sprinkling and watering; paving a pervious surface; reducing the anthropogenic heat (AH) release; using a “white roof”; increasing the fractional vegetation cover or leaf area index (LAI). To quantify the effect of these mitigation strategies, 26 sets of experiments are designed and implemented by running the integrated urban land model (IUM). The results of the sensitivity analysis indicate that sprinkling and watering is an effective measure for mitigating a SUHI for an entire day. Decreasing the AH release is also useful for both night- and daytime SUHI mitigation; however, the cooling extent is proportional to the diurnal cycle of AH. Increasing the albedo can reduce the LST in the daytime, especially when the solar radiation is significant; the cooling extent is approximately proportional to the diurnal cycle of the net radiation. Increasing the pervious surface percentage can mitigate the SUHI especially in the daytime. Increasing the fractional vegetation cover can mitigate the SUHI in the daytime but may aggravate the SUHI at night.

An Efficient Method for Multicomponent Synthesis of Spiro[4H-pyran-oxindole] Derivatives Catalyzed by Magnesium Perchlorate

Chunlei Wu,Runpu Shen,Jianhui Chen,Chunqi Hu 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.8

A simple and efficient method for the synthesis of spiro[4H-pyran-oxindole] derivatives by means of threecomponent reactions between isatins, malononitrile or ethyl cyano-acetate, and 1,3-dicarbonyl compounds in the presence of catalytic amount of magnesium perchlorate in 50% aqueous ethanol medium has been described.

Similarity measurement of the geometry variation sequence of intermediate process model

Chunlei Li,Liang Li,Xiaoye Wang 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.7

The reuse of machining process, by which the process for a new mechanical part is determined by referencing to the existing and matured processes, is an effective way of improving manufacturing and supporting innovation. To conduct the effective reuse, it is necessary to express and retrieve a specific process. A kernel technique of the expression and the retrieval is to measure the similarity of part’s geometry variation during the machining. To address this problem, a general framework of measuring the similarity between parts is proposed in this work. The geometry variation sequence of intermediate process model was established, and then a method to measure its similarity was invented. Two case studies are rendered and the result reveals that the proposed method is effective and can provide the support for the process retrieval and reuse in industry.

Jurisdiction Ratione Temporis in Successive International Investment Agreements: What Can Chinese Investors Learn from the Ping An Case?

Chunlei Zhao 이준국제법연구원 2017 China and WTO Review Vol.3 No.1

An Experimental Study on Negative Bending Behavior of Composite Bridge Decks with Steel-Fiber-Reinforced Concrete and Longitudinal Bulb-Flat Ribs

Chunlei Zhang,Changyu Shao,Qing-Tian Su,Changyuan Dai 한국강구조학회 2023 International Journal of Steel Structures Vol.23 No.3

Orthotropic steel–concrete composite bridge deck is a structure composed of an orthotropic steel bridge deck and a cement-based rigid overlay. In recent years, it has been increasingly used to strengthen existing steel decks and build new bridges. Although composite decks with various structural forms and materials have been widely used, studies on the structural behavior of composite bridge decks are still somewhat lacking, and the design approach has not been fully clear. In this study, the mechanical behaviors of a composite bridge deck composed of 80 mm steel-fiber-reinforced concrete (SFRC) and longitudinal bulb-flat ribs were investigated under negative bending. Loading tests of two full-scale composite decks were carried out to study the variations of stiffness, concrete cracks, and structural strain during the loading process. The elastoplastic cross-sectional analysis method and the rigid-plastic analysis method were used in theoretical calculation and the results were compared with the experimental results. It was found that when the composite bridge deck was subjected to negative bending, both the structural deformation and strain variation showed two stages, i.e., elastic stage and elastic–plastic stage, indicating good ductility. In the ultimate failure state, the longitudinal bulb-flat ribs buckled, and the adverse effect of the buckling on bending resistance was revealed. The contribution of the tensile strength of SFRC to the bending resistance was also studied. Furthermore, a new calculation method for the negative bending resistance of this type of composite decks was proposed.

Nutrient and ruminal fermentation profiles of Camellia seed residues with fungal pretreatment

Chunlei Yang,Zhongfa Chen,Yuelei Wu,Jia-Kun Wang 아세아·태평양축산학회 2019 Animal Bioscience Vol.32 No.3

Objective: The experiment was conducted to evaluate the effects of four fungal pretreatments on the nutritional value of Camellia seed residues, and to evaluate the feeding value of pre-treated Camellia seed residues for ruminants. Methods: Camellia seed residues were firstly fermented by four lignin degrading fungi, namely, Phanerochaete chrysosporium (P. chrysosporium)-30942, Trichoderma koningiopsis (T. koningiopsis)-2660, Trichoderma aspellum (T. aspellum)-2527, or T. aspellum-2627, under solid-state fermentation (SSF) conditions at six different incubation times. The nutritional value of each fermented Camellia seed residues was then analyzed. The fermentation profiles, organic matter degradability and metabolizable energy of each pre-treated Camellia seed residue were further evaluated using an in vitro rumen fermentation system. Results: After 5 days of fermentation, P. chrysosporium-30942 had higher degradation of lignin (20.51%), consumed less hemicellulose (4.02%), and the SSF efficiency reached 83.43%. T. koningiopsis-2660 degraded more lignin (21.54%) and consumed less cellulose (20.94%) and hemicellulose (2.51%), the SSF efficiency reached 127.93%. The maximum SSF efficiency was 58.18% for T. aspellum-2527 and 47.61% for T. aspellum-2627, appeared at 30 and 15 days respectively. All the fungal pretreatments significantly improved the crude protein content (p<0.05). The Camellia seed residues pretreated for 5 days were found to possess significantly increased organic matter degradability, volatile fatty acid production and metabolizable energy (p<0.05) after the treatment of either P. chrysosporium-30942, T. koningiopsis-2660 or T. aspellum-2527. The fungal pretreatments did not significantly change the rumen fermentation pattern of Camellia seed residues, with an unchanged ratio of acetate to propionate. Conclusion: The fungi showed excellent potential for the solid-state bioconversion of Camellia seed residues into digestible ruminant energy feed, and their shorter lignin degradation characteristics could reduce loss of the other available carbohydrates during SSF.