Aqueous Processing and Effects of V2O5 on Microwave Dielectric Properties of Multilayer Li1.075Nb0.625Ti0.45O3 Ceramics

Shaochun Li,Yongjuan Geng,Tiejun Zhao,Zuquan Jin,Peng Zhang 대한금속·재료학회 2014 ELECTRONIC MATERIALS LETTERS Vol.10 No.1

In the present work, we report the development of an aqueous tape casting method and a low temperature co-firing process for fabrication of multilayer Li1.075Nb0.625Ti0.45O3 microwave dielectric ceramics. A co-binder, consisting of polyvinyl acetate latex (PVAc) and polyvinyl alcohol (PVA), was used to prepare aqueous Li1.075Nb0.625Ti0.45O3 tapes. PVA addition increased the tape flexibility and adhesiveness but resulted in decreased tensile strength. Rheological tests indicated that the aqueous ceramic slurry exhibited a typical shear thinning behavior without thixotropy, suitable for tape casting. Scanning electron microscopy (SEM) studies revealed that the green tapes have a defect-free surface and that the multilayer ceramics sintered at 900°C have a fine plate like, grainy microstructure of uniform size. At lower temperatures, increased densification rates were achieved by addition of V2O5 to Li1.075Nb0.625Ti0.45O3 ceramics. The saturated bulk densities and dielectric constants (εr) of Li1.075Nb0.625Ti0.45O3 multilayer ceramics affected by lower sintering temperatures with an increase in V2O5 doping, and then an improvement in the quality factor (Q × f value) of the samples was achieved at the lower sintering temperatures. As a result, the εr of 64.9 and the Q × f value of 8800 GHz were obtained in the sample with an addition of 3 wt. % V2O5, sintered at a temperature of 900°C. No reaction was observed between the ceramic and silver layers when sliver inner-electrode, was sintered with ceramic tapes at 900°C.

Preparation and Dieletrical Properties of Li1.075Nb0.625Ti0.45O3 Powders by Hydrothermal Method

Shaochun Li,Yongjuan Geng,Tiejun Zhao,Peng Zhang 대한금속·재료학회 2012 ELECTRONIC MATERIALS LETTERS Vol.8 No.4

A hydrothermal method has been developed and shown to be effective for the preparation of Li1.075Nb0.625Ti0.45O3(LNT) nano-particles. Hydrothermal reaction temperature was in the range from 120°C - 200°C. The crystalline structure and morphology of the prepared particles have been characterized by x-ray diffraction and scanning electron microscopy. Results indicate that hydrothermal temperature had a great effect on the phase formation and morphology of the particles. The prepared powders crystallized at 140°C, and the pure LNT phase was formed at 180°C. The size of LNT particles increased with increasing reaction temperature, and plate-like LNT particles with thickness of 15 - 30 mm and a diameter of 80 - 200 mm were obtained at 200°C. It was found that LNT powders synthesized at 180°C gave the LNT ceramics the highest microwave dielectric properties (εr = 66, Q×f = 8946 GHz) due to good crystallization and low particle size.

Aqueous processing of Li1.075Nb0.625Ti0.45O3 green tapes

Shaochun Li,Yongjuan Geng,Qilong Zhang,Hui Yang 한양대학교 세라믹연구소 2011 Journal of Ceramic Processing Research Vol.12 No.2

An aqueous tape casting of Li1.075Nb0.625Ti0.45O3 (LNT) ceramics was developed using PCA-NH4 as dispersant, PVA as binder and EG as plasticizer. Flexible, defect-free and smooth tapes of LNT were successfully produced. The study focused on obtaining the optimum slurry formulations and on the effects of the processing parameters such as the stability, the rheology on the properties on the tape characteristics. Surface properties of LNT powders in the aqueous suspensions are distinctly influenced by PCA-NH4. The zeta potential measurement showed that the isoelectric point (IEP) of LNT powders in the absence of dispersant corresponds to a pH value of 3.7. The zeta potential values (absolute values) increased with the amount of dispersant and up to its maximum near pH 9-10. The rheology measurements of all the slurries investigated showed the desired shear thinning behavior, indicating that the LNT slurry was homogenous and well stabilized. An optimum formulation for the tape was investigated and it was shown that a high solid loading (50 wt%) would lead to a high relative green density (46.7%). Homogenous, smooth, and defect-free green tapes were successfully obtained by an appropriate slurry formula.

Identification and characterization of heat shock proteins in a parasitic wasp Chouioia cuneae (Hymenoptera: Eulophidae)

Li‐Na Pan,Feng-ZhuWANG,Xin-Yue ZHANG,Yan-Ni ZHAO,Geng-Ping ZHU,Min LI 한국곤충학회 2018 Entomological Research Vol.48 No.3

Heat shock proteins (HSPs) are known to be induced in response to various stress factors. Although HSPs have been studied in a number of insects, not much is known about HSPs in the natural enemies of insects, especially parasitoids. In this study, we identified and characterized five full‐length HSP genes (Cchsp40, Cchsp60, Cchsp70, Cchsp83, and Cchsp90) from an endoparasitic chalcid wasp, Chouioia cunea, which parasitizes the fall webworm, Hyphantria cunea pupae, a worldwide pest. The expression of Cchsps in response to temperature, pesticide stresses and UV radiation were also investigated by quantitative real‐time polymerase chain reaction (RT‐qPCR). The results showed that all five Cchsps were induced in response to hot and cold temperatures. Four pesticides induced the abundant expression of Cchsp70, Cchsp83 and Cchsp90 while ultraviolet radiation up‐regulated Cchsp40, Cchsp70, Cchsp83 and Cchsp90. These results indicate the different transcriptional profiles of the five different Cchsps in response to various abiotic stresses. The findings of this study provide insights into the response of C. cunea to abiotic stresses and insight into the use of this parasitoid in biological control strategies.

Differential Protein Expression Profile Between CD20 Positive and Negative Cells of the NCI-H929 Cell Line

Geng, Chuan-Ying,Liu, Nian,Yang, Guang-Zhong,Liu, Ai-Jun,Leng, Yun,Wang, Hui-Juan,Li, Li-Hong,Wu, Yin,Li, Yan-Chen,Chen, Wen-Ming Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.11

At present, multiple myeloma (MM) remains an incurable disease and cologenic cells may be responsible for disease relapse. It has been proposed that CD20+/CD138- NCI-H929 cells could be hallmarks of MM clonogenic cells. Here, the immunology phenotype of NCI-H929 cells is described. Only a small population of CD20+/CD138- cells (<1%) was found in the NCI-H929 cell line, but CD20+/CD138- cells were not detected. We found that CD20+/CD138+ cells were able to exhibit cologenic capacity by colony formation assay and continuous passage culture. Proteins were analyzed by 1D-SDS-PAGE and TMT based quantitative differential liquid chromatography tandem mass spectrometry (LC-MS/MS). 1,082 non-redundant proteins were identified, 658 of which were differentially expressed with at least a 1.5-fold difference. 205 proteins in CD20+ cells were expressed at higher levels and 453 proteins were at lower levels compared with CD20- cells. Most proteins had catalytic and binding activity and mainly participated in metabolic processes, cell communication and molecular transport. These results proved that there are different biological features and protein expression profile between CD20+ and CD20- cells in the NCI-H929 cell line.

Transcriptome Analysis Reveals Molecular Mechanisms Underlying Methyl Jasmonate-mediated Biosynthesis of Protopanaxadiol-type Saponins in Panax notoginseng Leaves

Li Ying,Lin Yuan,Jia Bing,Chen Geng,Shi Huineng,Xu Rui,Li Xuejiao,Tang Junrong,Tang Qingyan,Zhang Guanghui,Yang Jianli,Fan Wei,Yang Shengchao 한국식물학회 2022 Journal of Plant Biology Vol.65 No.1

Methyl jasmonate (MeJA) has been widely used to improve the biosynthesis of secondary metabolites such as triterpenoid saponins in medicinal plants. However, the underlying molecular mechanisms remain poorly understood. Differing from roots that accumulate protopanaxatriol-type saponins, Panax notoginseng leaves with a lower biomass mainly contain protopanaxadiol (PPD)-type saponins. Therefore, it is interesting to explore whether MeJA can activate the biosynthesis of PPD-type saponins in P. notoginseng leaves. In this study, we found MeJA could effectively induce the accumulation of PPD-type saponins, including ginsenoside Rb1, Rc, Rb2, Rb3 and notoginsenoside Fa, Fe in P. notoginseng leaves based on a newly established high-performance liquid chromatography method. Transcriptome analysis showed that differentially expressed genes (DEGs) induced by MeJA were mainly enriched in “terpenoid backbone biosynthesis”, “biosynthesis of unsaturated fatty acids”, “sesquiterpenoid and triterpenoid biosynthesis”, “fatty acid metabolism”, and “phenylpropanoid biosynthesis”. Furthermore, the expression profile and quantitative real-time PCR analysis of DEGs showed that MeJA could positively induce the molecular response of endogenous jasmonic acid (JA) signaling pathway, and increased PPD-type saponins mediated by MeJA in P. notoginseng leaves may be related to the high expression of FPS, SS, SE, DS and UGTs, and the low expression of CYP716A53v2 and β-AS. The results provide a molecular understanding for MeJA-elicited biosynthesis of triterpenoid saponins and facilitate the further characterization of the genes responsible for biosynthesis of PPD-type saponins in P. notoginseng leaves.

Design for a Dual-Frequency Antenna-in-Package

Li Li,Liping Han,Guorui Han,Xinwei Chen,Yanfeng Geng,Wenmei Zhang 한국전자통신연구원 2010 ETRI Journal Vol.32 No.4

For an antenna-in-package (AiP), via holes are used to connect the antenna ground and system ground. In this letter, a dual-frequency AiP with a U-slot embedded in the patch is proposed. By properly arranging three via holes under the non-radiating edge, an AiP with two resonant frequencies is realized. Then a U-slot is embedded in the patch to further improve the bandwidth of the AiP. To validate the proposed design, an AiP with the bandwidth of 4.49% at 2.45 GHz and 6.02% at 5.32 GHz is achieved and fabricated. The measured results agree with the simulated results.

Forecasting Logistics Demand Using Unbiased GM (1,1) Model Optimized by AIWPSO Algorithm

Li-Yan Geng,Zhan-Fu Zhang 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.10

Accurate forecast of logistics demand can provide scientific guidance for logistics planning and decision making. With the complexity and uncertainty characteristics in logistics demand, the forecasting of logistics demand shows comprehensive and complex. The forecasting precision of the traditional forecasting methods often are not satisfying. It is necessary to look for novel forecasting methods to enhance the forecasting precision of logistics demand. Integrating the unbiased GM (1,1) model (UGM (1,1)) into the adaptive inertia weight particle swarm optimization (AIWPSO) algorithm, this paper developed a novel model for forecasting logistics demand, called AIWPSO-UGM (1,1) model, in which the UGM (1,1) model was used to forecast logistics demand and the AIWPSO algorithm was adopted to optimize the grey parameters needed in UGM (1,1) model. Two examples were selected to prove the out-of-sample performance of the AIWPSO-UGM (1,1) model in forecasting logistics demand. The results imply that the proposed AIWPSO-UGM (1,1) model performs better in logistics demand forecasting compared to the GM (1,1) model optimized by AIWPSO algorithm (AIWPSO-GM (1,1)), UGM (1,1), and GM (1,1) models.

An Efficient Model Based on Smoothed ℓ₀ Norm for Sparse Signal Reconstruction

( Yangyang Li ),( Guiling Sun ),( Zhouzhou Li ),( Tianyu Geng ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.4

Compressed sensing (CS) is a new theory. With regard to the sparse signal, an exact reconstruction can be obtained with sufficient CS measurements. Nevertheless, in practical applications, the transform coefficients of many signals usually have weak sparsity and suffer from a variety of noise disturbances. What's worse, most existing classical algorithms are not able to effectively solve this issue. So we proposed an efficient algorithm based on smoothed ℓ₀ norm for sparse signal reconstruction. The direct ℓ₀ norm problem is NP hard, but it is unrealistic to directly solve the ℓ₀ norm problem for the reconstruction of the sparse signal. To select a suitable sequence of smoothed function and solve the ℓ₀ norm optimization problem effectively, we come up with a generalized approximate function model as the objective function to calculate the original signal. The proposed model preserves sharper edges, which is better than any other existing norm based algorithm. As a result, following this model, extensive simulations show that the proposed algorithm is superior to the similar algorithms used for solving the same problem.

A GROUNDED THEORY APPROACH TO EXPLORING THE PHENOMENON OF SELLER MANIPULATIONS OF ONLINE PRODUCT REVIEWS

Chunyu Li,Ling Peng,Geng Cui 글로벌지식마케팅경영학회 2016 Global Marketing Conference Vol.2016 No.7

We adopt a semi-grounded theory approach to investigate the impact of different review manipulation tactics. Shoppers take a negative view toward seller manipulations, but the degree of negativity varies across different tactics. Moreover, different manipulations tactics vary in the ease of detection, perceived unethicality, and the effect on consumer perceptions.