H2 Metabolism revealed by metagenomic analysis of subglacial sediment from East Antarctica

Zhifeng Yang,Yu Zhang,Yongxin Lv,Wenkai Yan,Xiang Xiao,Bo Sun,Hongmei Ma 한국미생물학회 2019 The journal of microbiology Vol.57 No.12

Subglacial ecosystems harbor diverse chemoautotrophic microbial communities in areas with limited organic carbon, and lithological H2 produced during glacial erosion has been considered an important energy source in these ecosystems. To verify the H2-utilizing potential there and to identify the related energy-converting metabolic mechanisms of these communities, we performed metagenomic analysis on subglacial sediment samples from East Antarctica with and without H2 supplementation. Genes coding for several [NiFe]- hydrogenases were identified in raw sediment and were enriched after H2 incubation. All genes in the dissimilatory nitrate reduction and denitrification pathways were detected in the subglacial community, and the genes coding for these pathways became enriched after H2 was supplied. Similarly, genes transcribing key enzymes in the Calvin cycle were detected in raw sediment and were also enriched. Moreover, key genes involved in H2 oxidization, nitrate reduction, oxidative phosphorylation, and the Calvin cycle were identified within one metagenome-assembled genome belonging to a Polaromonas sp. As suggested by our results, the microbial community in the subglacial environment we investigated consisted of chemoautotrophic populations supported by H2 oxidation. These results further confirm the importance of H2 in the cryosphere.

H∞ CONTROL FOR BATTERY/SUPERCAPACITOR HYBRID ENERGY STORAGE SYSTEM USED IN ELECTRIC VEHICLES

Zhifeng Bai,Zengfeng Yan,Xiaolan Wu,Jun Xu,Binggang Cao 한국자동차공학회 2019 International journal of automotive technology Vol.20 No.6

This paper proposes a control strategy of a hybrid energy storage system (HESS) based on simplified 2th-order model. The HESS uses a bidirectional DC/DC converter to connect the supercapacitors (SC) with the battery. Two control objectives, the output current of the SC during the traction procedure and the charging current of the SC while regenerative braking, are regulated by using the DC/DC converter. Two H∞ controllers are designed to control the output and charging current of the SC to their reference values, which are generated by the energy management strategy (EMS). Experimental results show that the proposed control method achieves a satisfactory performance, including a low steady-state tracking error and high response speed when the load power varies in a wide range.

Thermodynamics stability, electronic structures and spectroscopic properties of defects and Ce3+ ions in Y2O3

Wang Yan,Wen Jun,Zheng Jiangyun,Deng Zhifeng,Zhou Yueyu,Jiang Guisheng,Xia Qiangsheng,He Enjie,Ning Lixin 한국물리학회 2021 Current Applied Physics Vol.26 No.-

Thermodynamic properties, electronic structures and spectroscopic properties of defects and Ce3+ in Y2O3 are studied by using the hybrid density functional theory associated with multi-reference configuration interaction ab-initio calculations. Thermodynamic transition energy levels of the easily generated oxygen vacancies in the host are analyzed according to HSE06-calculated formation energies, which may be conducive to interpretations of the persistent luminescence (PersL) of Y2O3-based phosphors. Besides, the locations of impurity states (caused by VO and Ce3+) in energy bands are obtained from derived density of states. Moreover, energies and oscillator strengths of 4f1 → 5d1 5 transitions of Ce3+ ions (at Y1 and Y2 sites) calculated from the CASSCF/CASPT2/ RASSI SO method agree reasonably well with experimental excitation spectra of Y2O3: Ce3+ phosphors, achieving the assignment of excitation spectra. The presented calculations can be applied to identify luminescent centers in Ce3+-doped phosphors and reveals possible native defects and their roles in the PersL of phosphors.

Compression history detection for MP3 audio

( Diqun Yan ),( Rangding Wang ),( Jinglei Zhou ),( Chao Jin ),( Zhifeng Wang ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.2

Compression history detection plays an important role in digital multimedia forensics. Most existing works, however, mainly focus on digital image and video. Additionally, the existed audio compression detection algorithms aim to detect the trace of double compression. In real forgery scenario, multiple compression is more likely to happen. In this paper, we proposed a detection algorithm to reveal the compression history for MP3 audio. The statistics of the scale factor and Huffman table index which are the parameters of MP3 codec have been extracted as the detecting features. The experimental results have shown that the proposed method can effectively identify whether the testing audio has been previously treated with single/double/triple compression.

Energy-Efficient Algorithm for Assigning Verification Tasks in Cloud Storage

( Guangwei Xu ),( Zhifeng Sun ),( Cairong Yan ),( Xiujin Shi ),( Yue Li ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.1

Mobile Cloud Computing has become a promising computing platform. It moves users` data to the centralized large data centers for users` mobile devices to conveniently access. Since the data storage service may not be fully trusted, many public verification algorithms are proposed to check the data integrity. However, these algorithms hardly consider the huge computational burden for the verifiers with resource-constrained mobile devices to execute the verification tasks. We propose an energy-efficient algorithm for assigning verification tasks (EEAVT) to optimize the energy consumption and assign the verification tasks by elastic and customizable ways. The algorithm prioritizes verification tasks according to the expected finish time of the verification, and assigns the number of checked blocks referring to devices` residual energy and available operation time. Theoretical analysis and experiment evaluation show that our algorithm not only shortens the verification finish time, but also decreases energy consumption, thus improving the efficiency and reliability of the verification.

Study on Atom Transfer Radical Polymerization Initiated by p-Nitrophenyl Initiator and Synthesis of Amino End-functionalized Polymers Thereof

Tianyu Qu,Wenqian Cai,Zhifeng Fu,Yan Shi 한국고분자학회 2010 Macromolecular Research Vol.18 No.7

Atom transfer radical polymerization (ATRP) of styrene initiated by p-nitrobenzyl bromide and ATRP of methyl methacrylate (MMA) initiated by p-nitrobenzyl α-bromoisobutylate were carried out using CuBr/2,2’-bipyridine as a catalyst system. Controlled radical polymerization processes were involved in both reactions resulting in polystyrene and PMMA with nitrophenyl ends. The nitro ends of the polymers were converted to the amino-terminals through reduction in acetone with Fe and hydrochloric acid used as the reducing agent. The effect of nitrophenyl compounds on ATRP was examined and weak retardation was observed in both ATRP systems.

Investigation on Chain Transfer Reaction of Benzene Sulfonyl Chloride in Styrene Radical Polymerization

Li, Cuiping,Fu, Zhifeng,Shi, Yan The Polymer Society of Korea 2009 Macromolecular Research Vol.17 No.8

The free radical polymerization of styrene was initiated with azobis(isobutyronitrile) in the presence of benzene sulfonyl chloride. Analysis of the terminal structures of the obtained polystyrene with $^1H$ NMR spectroscopy revealed the presence of a phenyl sulfonyl group at the ${\alpha}$-end and a chlorine atom at the ${\omega}$-end of each polystyrene chain. The terminal chlorine atom in the polystyrene chains was further confirmed through atom transfer radical polymerization (ATRP) of styrene and methyl acrylate using the obtained polystyrenes as macroinitiators and CuCl/2,2'-bipyridine as the catalyst system. GPC traces of the products obtained in ATRP at different reaction times were clearly shifted to higher molecular weight direction, indicating that nearly all the macroinitiator chains initiated ATRP of the second monomers. In addition, the number-average molecular weights of the polystyrenes increased directly proportional to the monomer conversions, and agreed well with the theoretical ones.

Tripartite Motif Containing 3 inhibits the aggressive behaviors of papillary thyroid carcinoma and indicates lower recurrence risk

Song Yubao,Gao Zefeng,Yan Zhifeng,Zheng Caihong 한국유전학회 2022 Genes & Genomics Vol.44 No.4

Background: Tripartite Motif Containing 3 (TRIM3) has been reported to be downregulated in several malignancies. However, its prognostic significance in thyroid cancer remains unknown. Objective: Here we aimed to investigate TRIM3's expression and its involvement in papillary thyroid carcinoma (PTC). Methods: Clinicopathological analyses were performed in patients with PTC. Expression of TRIM3 protein was evaluated by IHC. The prognostic role of TRIM3 in PTC patients was assessed by univariate and multivariate analyses. Cell proliferation and invasion were tested in two PTC cell lines following overexpression or knockdown. Results: TRIM3 was decreased in PTC tissues compared to adjacent thyroid tissues on both mRNA and protein levels. Additionally, low expression of TRIM3 was significantly related to tumor size, lymph node metastasis and TNM stage. Moreover, TRIM3 was identified as an independent prognosis factor by multivariate analysis. Cellular data revealed that TRIM3 can inhibit the proliferation and invasion of PTC cells. Consistently, TRIM3 can upregulate the expression level of E-cadherin, while downregulate N-cadherin, Vimentin, and cyclin D1 expression. Conclusions: TRIM3 expression was downregulated in PTC tissues comparing with that in adjacent nontumorous thyroid tissues. Lower TRIM3 expression in PTC can contribute independently to a poorer prognosis by enhancing PTC proliferation and invasion, highlighting its potential as a novel therapeutic target and prognostic biomarker.

Separation and Characterization of Waste Cotton/polyester Blend Fabric with Hydrothermal Method

Wensheng Hou,Chen Ling,Sheng Shi,Zhifeng Yan,Meiling Zhang,Bonan Zhang,Jinming Dai 한국섬유공학회 2018 Fibers and polymers Vol.19 No.4

In the study, a good separation efficiency of waste cotton/polyester blended fabrics (WBFs) was achieved, with dilute hydrochloric acid as the catalyst under hydrothermal conditions. The morphology and structure of the hydrothermal products including solid and liquid products were characterized by scanning electron microscopy, Fourier transform Infrared spectroscopy, X-ray diffraction, and high-performance liquid chromatography techniques and compared to the untreated polyester and cotton. The results show that the cotton fiber decomposed completely while polyester still retained its fiber characteristics after 3 h of reaction time at 150 oC and 1.5 wt% dilute hydrochloric acid. The hydrolysis of cellulose resulted in a recovery of 96.24 % of the polyester without significant change in its properties; 48.21 % of cellulose powder can be further used as the raw material of microcrystalline cellulose (MCC) and 15.57 % of glucose.

A field determination method of D-T neutron source yields based on oxygen prompt gamma rays

Xiongjie Zhang,Bin Tang,Geng Nian,Haitao Wang,Lijiao Zhang,Yan Zhang,Rui Chen,Zhifeng Liu,Jinhui Qu Korean Nuclear Society 2023 Nuclear Engineering and Technology Vol.55 No.7

A field determination method for small D-T neutron source yield based on the oxygen prompt gamma rays was established. A neutron-gamma transport equation of the determination device was developed. Two yield field determination devices with a thickness of 20 mm and 50 mm were made. The count rates of the oxygen prompt gamma rays were calculated using three energy spectra processing approaches, which were the characteristic peak of 6.13 MeV, the overlapping peak of 6.92 MeV and 7.12 MeV, and the total energy area. The R-square of the calibration curve is better than 94% and the maximum error of the yield test is 5.21%, demonstrating that it is feasible to measure the yield of D-T neutron source by oxygen prompt gamma rays. Additionally, the results meet the requirements for field determination of the conventional D-T neutron source yield.