http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Evaluation of Freeze-dried Tibetan Kefir co-culture as a Starter for Production of Bod ljong Cheese
Jun Mei,Fei Feng,Qizhen Guo,Yunfei Li,Yan Wu 한국식품과학회 2015 Food Science and Biotechnology Vol.24 No.3
The physico-chemical profile, proteolysis, flavor, and microbiological changes were investigated, and a sensory evaluation was performed for Bod ljong cheese prepared using a freeze-dried Tibetan kefir co-culture during ripening. The proteolysis level was high, the pH 4.6-soluble nitrogen, 12% trichloroacetic acid-soluble nitrogen, water soluble nitrogen, and total free amino acid contents increased, and the protein content decreased during ripening. The effect of the starter culture on production of aroma-related compounds responsible for cheese flavor was also studied using solidphase microextraction GC-MS techniques. Alcohols and esters were the most abundant volatile compounds. Microbial counts during ripening increased steadily. Lactic acid bacteria, Lactobacillus and Lactococcus, were the dominant flora during ripening. Enterococci, Enterobacteriaceae, and Salmonella sp. bacterial counts were low or zero. The cheese was subjected to sensory evaluation by a panel and compared to commercial Bod ljong-type cheese.
Jun Mei,Qizhen Guo,Yan Wu,Yunfei Li,Huaning Yu 한국식품과학회 2015 Food Science and Biotechnology Vol.24 No.2
The use of a freeze-dried Tibetan kefir coculture as a starter for production of Camembert-type cheese was investigated. Maturation of produced cheese was monitored for 35 days and the chemical composition, proteolysis, lipolysis, and volatile compounds were studied. The cheese underwent proteolysis. The content of pH 4.6- soluble nitrogen, 12% trichloroacetic acid-soluble nitrogen, and the total free amino acid content increased while the total nitrogen content decreased. Palmitic, myristic, oleic, and capric acid were the representative free fatty acids, which increased in amount during ripening. A total of 45 compounds were detected, including 16 acids, 8 ketones, 6 alcohols, 7 esters, and 8 unclassified compounds. Volatile carboxylic acids were abundant in the headspace of the cheese.
Quasi-Fixed-Frequency Hysteresis Current Tracking Control Strategy for Modular Multilevel Converters
Jun Mei,Yu Ji,Xiaozhou Du,Tian Ma,Can Huang,Qinran Hu 전력전자학회 2014 JOURNAL OF POWER ELECTRONICS Vol.14 No.6
This study proposes a quasi-fixed-frequency hysteresis current tracking control strategy for modular multilevel converters (MMCs) on the basis of voltage partition principle. First, by monitoring the grid voltage and the deviation between the output and reference currents, the output voltage is determined, thus prompting the output current to quickly and efficiently track the given current. Second, the voltages of the upper/lower capacitor of the arm and the voltages between the upper and lower arms are balanced by combining these arms with virtual loop mapping and arm voltage balance control, respectively. In particular, the proposed method is designed for any level and number of sub-modules. The validity of the proposed method is verified by simulations and experimental results of a five-level MMC prototype.
Research on Advanced Control Strategies of Induction Motor System
Junmei Zhao,Zhijie Zhang,Yifeng Ren 보안공학연구지원센터 2015 International Journal of Smart Home Vol.9 No.1
The induction motor (IM) is a nonlinear, uncertain, and complex controlled object that is difficult to drive and control. When the system parameters change or has external disturbance signal, the system cannot return to the original state of equilibrium, to which active disturbance rejection control (ADRC) has been shown to be an effective solution. ADRC regards the external disturbance and strong coupling structure of induction motor (IM) as the total disturbance, which is observed and compensated by extended state observer, and does not depend accurate system mathematical model, and has strong anti-interference and robustness. In this paper, a new control strategy----Tornambe control is used in the speed regulator of IM system instead of ADRC. It has the similar control thought to the ADRC, and has the simple structure, less setting parameters, and is convenient to study and use. In this paper, the direct torque control strategy is adopted to drive the IM. The active disturbance rejection control and Tornambe control are used instead of traditional speed regulator, the system performance of the two control strategy are compared. The results show that the system performance of TC strategy is better than that of ADRC.
Statistical considerations underpinning an alignment-free sequence comparison method
Junmei Jing,Conrad J. Burden,Sylvain Forêt,Susan R. Wilson 한국통계학회 2010 Journal of the Korean Statistical Society Vol.39 No.3
The D2 statistic is defined as the number of word matches of prespecified length k, with up to t mismatches, shared between two given sequences. This statistic finds its application in alignment-free comparisons of biological sequences. It has two main advantages over alignment-based methods for nucleotide and amino-acid sequence comparisons, such as BLAST (basic local alignment search tool). These are (i)D2 does not assume that homologous segments are contiguous, and (ii) the algorithm is computationally extremely fast, the runtime being proportional to the size of the sequences in the case of exact matches. This review article summarises results to date on determining the distributional properties of the D2 statistic for a range of biologically relevant parameters, describes existing applications of the method, and outlines future research directions.
( Tingting Yu ),( Junmei Ding ),( Qingxia Zheng ),( Nanyu Han ),( Jialin Yu ),( Yunjuan Yang ),( Junjun Li ),( Yuelin Mu ),( Qian Wu ),( Zunxi Huang ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.4
est19 is a gene from Bacillus sp. K91 that encodes a new esterase. A comparison of the amino acid sequence showed that Est19 has typical Ser-Gly-Asn-His (SGNH) family motifs and could be grouped into the SGNH hydrolase family. The Est19 protein was functionally cloned, and expressed and purified from Escherichia coli BL21(DE3). The enzyme activity was optimal at 60°C and pH 9.0, and displayed esterase activity towards esters with short-chain acyl esters (C2-C6). A structural model of Est19 was constructed using phospholipase A1 from Streptomyces albidoflavus NA297 as a template. The structure showed an α/β-hydrolase fold and indicated the presence of the typical catalytic triad Ser49-Asp227-His230, which were further investigated by site-directed mutagenesis. To the best of our knowledge, Est19 is a new member of the SGNH hydrolase family identified from thermophiles, which may be applicable in the industrial production of semisynthetic β-lactam antibiotics after modification.
Omp16, a conserved peptidoglycan-associated lipoprotein, is involved in Brucella virulence in vitro
Feijie Zhi,Dong Zhou,Junmei Li,Lulu Tian,Guangdong Zhang,Yaping Jin,Aihua Wang 한국미생물학회 2020 The journal of microbiology Vol.58 No.9
Brucella, the bacterial agent of common zoonotic brucellosis, primarily infects specific animal species. The Brucella outer membrane proteins (Omps) are particularly attractive for developing vaccine and improving diagnostic tests and are associated with the virulence of smooth Brucella strains. Omp16 is a homologue to peptidoglycan-associated lipoproteins (Pals), and an omp16 mutant has not been generated in any Brucella strain until now. Very little is known about the functions and pathogenic mechanisms of Omp16 in Brucella. Here, we confirmed that Omp16 has a conserved Pal domain and is highly conserved in Brucella. We attempted to delete omp16 in Brucella suis vaccine strain 2 (B. suis S2) without success, which shows that Omp16 is vital for Brucella survival. We acquired a B. suis S2 Omp16 mutant via conditional complementation. Omp16 deficiency impaired Brucella outer membrane integrity and activity in vitro. Moreover, inactivation of Omp16 decreased bacterial intracellular survival in macrophage RAW 264.7 cells. B. suis S2 and its derivatives induced marked expression of IL-1β, IL-6, and TNF-α mRNA in Raw 264.7 cells. Whereas inactivation of Omp16 in Brucella enhanced IL-1β and IL-6 expression in Raw 264.7 cells. Altogether, these findings show that the Brucella Omp16 mutant was obtained via conditional complementation and confirmed that Omp16 can maintain outer membrane integrity and be involved in bacterial virulence in Brucella in vitro and in vivo. These results will be important in uncovering the pathogenic mechanisms of Brucella.