Missing particle associated with two bottom quarks at the LHC: Mono- b versus 2b with razor variables

Chen, Ning,Kang, Zhaofeng,Li, Jinmian American Physical Society 2017 Physical Review D Vol.95 No.1

<P>The extended Higgs sector, such as by a second Higgs doublet of type II, provides portals to the dark sector which contain missing particles at the LHC, e.g., dark matter particles. In this paper, working in the simplified model and taking into consideration the wide decay-width effect of the mediator, we analyze the characteristic signatures of mono-b + MET and 2b + MET at the LHC. The latter signature was believed to be ineffective, while we found that, with the aid of razor shape analysis, it should be as important as the mono-b signature. In the region of relatively low mediator mass (below a few hundred GeV), by requiring a signal-to-background ratio greater than a few percent, the 2b-tagged razor analysis has comparable sensitivity to the mono-b search; it is even better for a mediator lighter than similar to 200 GeV.</P>

Effect of pH Buffer and Carbon Metabolism on the Yield and Mechanical Properties of Bacterial Cellulose Produced by Komagataeibacter hansenii ATCC 53582

( Zhaofeng Li ),( Si-qian Chen ),( Xiao Cao ),( Lin Li ),( Jie Zhu ),( Hongpeng Yu ) 한국미생물생명공학회(구 한국산업미생물학회) 2021 Journal of microbiology and biotechnology Vol.31 No.3

Bacterial cellulose (BC) is widely used in the food industry for products such as nata de coco. The mechanical properties of BC hydrogels, including stiffness and viscoelasticity, are determined by the hydrated fibril network. Generally, Komagataeibacter bacteria produce gluconic acids in a glucose medium, which may affect the pH, structure and mechanical properties of BC. In this work, the effect of pH buffer on the yields of Komagataeibacter hansenii strain ATCC 53582 was studied. The bacterium in a phosphate and phthalate buffer with low ionic strength produced a good BC yield (5.16 and 4.63 g/l respectively), but there was a substantial reduction in pH due to the accumulation of gluconic acid. However, the addition of gluconic acid enhanced the polymer density and mechanical properties of BC hydrogels. The effect was similar to that of the bacteria using glycerol in another carbon metabolism circuit, which provided good pH stability and a higher conversion rate of carbon. This study may broaden the understanding of how carbon sources affect BC biosynthesis.

Correlation between the Thermo-physical Properties and Core Material Structure of Vacuum Insulation Panel: Role of Fiber Types

Tengzhou Xu,Zhaofeng Chen,Yong Yang,Zhou Chen,Junxiong Zhang,Cao Wu,Yang Liu 한국섬유공학회 2018 Fibers and polymers Vol.19 No.5

Vacuum insulation panel (VIP), which is composed of an evacuated core material encapsulated in an envelope and supplemented with a desiccant, is a high performance thermal insulation material. In this paper, thermos-physical properties of chopped fiber, centrifugal-spinneret-blow (CSB) fiber, flame-spinneret-blow (FSB) fiber and hybrid (CSB: FSB=1:1) fiber as fillers of vacuum insulation panel are explored. The results show that the increase of pore size can improve thermal insulation property; fibers distribute in 2-D structure, which can reduce the heat conduction, leads to reduce the thermal conductivity. VIP with chopped fiber has the best thermal insulation, and thermal conductivity is 1.4 mW/m.K. Due to difference of core materials, thermal insulation characteristics of VIP can be divided into three distinct regions based on the internal pressure range, i.e., (I) ≥12000 Pa region, (II) 80-12000 Pa region, (III) ≤ 80 Pa region. It also finds that service life of VIP can be improved by the reducing the pore size of core materials. VIP with different core materials shows different degradation and the degradation rate of VIP with FSB core material is minimum.

Best Moments Magnetotactic Bacteria Algorithm for Optimization

Ce Yang,Zhaofeng Chen 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.8

Magnetotactic bacteria optimization algorithm(MBOA) is an optimization algorithm based on the characteristics of magnetotactic bacteria, which is a kind of polyphyletic group of prokaryotes with the characteristics of magnetotaxis that make them orient and swim along geomagnetic field lines. In this paper, an improved MBOA is proposed. At first, it generates moments based on the interaction energy of cells. Then, the moments of cells are regulated based on the best cell. Some cells have chance to move towards the best one. At last, some worse cells will be replaced by randomly generated solutions in order to keep diversity. Thus, it can find optimum solution. It is tested on ten standard function problems and compared with many popular optimization algorithms, including CLPSO, LeDE and ABC. Experiment results show that the improved MBOA is very effective in optimization problems and has superior performance to the compared methods on many benchmark functions.

The Synthesis and Research of Glass Fiber Felts Coated with Graphene Oxide/Phenolic Resin Binder

Ya Hu,Zhaofeng Chen,Cao Wu,Fei Wang,Sheng Cui,Sufen Ai,Yong Yang 한국섬유공학회 2019 Fibers and polymers Vol.20 No.4

Glass fiber felts (GFFs) coated with reduced graphene oxide (RGO)/phenolic resin (PF) binder was prepared by in-situ reduction reaction, subsequently spraying, and curing process. The effects of the RGO content on the thermal, antiablative, hydrophobic, and mechanical properties of GFFs were studied. Fourier-transform infrared (FT-IR) spectra, X-ray diffraction (XRD) and electronic differential system (EDS) analysis revealed that the graphene oxide (GO) was reduced to RGO by phenol during the in-situ polymerization. Thermogravimetry (TG) and DTG analytical diagram demonstrated that the thermal stability of GFFs was also significantly improved with the addition of GO due to the barrier effect of the lamellar structure. Also, by addition of 0.4 wt% of GO, hydrophobicity was improved by 39 % and the tear strength was improved by 57 % owning to its unique structure and the effective external load transfer. Moreover, the compatibility with PF matrix was improved, endowing good anti-ablative, excellent hydrophobicity and mechanical properties for GFFs.

Support Vector Machine Optimization Based On Magnetic Bacteria Optimization Algorithm

Ce Yang,Zhaofeng Chen 보안공학연구지원센터 2015 International Journal of Hybrid Information Techno Vol.8 No.9

Classification performance of support vector machine (SVM) will be influenced by its model parameters. For this problem, a new method named magnetic bacteria optimization algorithm (MBOA) that optimizes the parameters of SVM is proposed. It is tested by the UCI standard data sets and compared with the other optimization algorithms, such as particle swarm optimization (PSO). Experimental results show that the MBOA can optimize the parameters of SVM well and has better performance than the compared algorithms.

SYNTHESIS OF PEG-ENCAPSULATED SUPERPARAMAGNETIC COLLOIDAL NANOCRYSTALS CLUSTERS

HUI WANG,YIMING LI,ZHAOFENG LUO,SHUAI ZHOU,JIN SHENG,QIANWANG CHEN 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2010 NANO Vol.5 No.6

PEG-encapsulated colloidal nanocrystal clusters (CNCs) have been synthesized via a one-step solvothermal process at a temperature of 230°C. The composition, phase, and morphology of these CNCs have been characterized by X-ray diffraction and transmission electron microscopy. Studies show that each particle is a cluster structure consisting of small primary iron oxide nanocrystals. Magnetic measurements reveal the superparamagnetic nature of these CNCs at room temperature. The CNCs with different sizes (80 nm or 95 nm) can be obtained by changing the time of reaction. The dispersibility and colloidal stability of these CNCs with PEG as the major surface group have also been discussed. In vitro cytotoxicity of these CNCs with different thickness PEG layer on HeLa cell has also been assayed. Cytotoxicity results reveal that the CNCs concentration and the incubation time can influence the cell viability, and the size of CNCs almost does not affect the cell viability.

Glycine and Triton X-100 Enhanced Secretion of Recombinant α-CGTase Mediated by OmpA Signal Peptide in Escherichia coli

Bin Li,Lei Wang,Lingqia Su,Sheng Chen,Zhaofeng Li,Jian Chen,Jing Wu 한국생물공학회 2012 Biotechnology and Bioprocess Engineering Vol.17 No.6

OmpA signal peptide mediated cgt gene from Paenibacillus macerans JFB05-01 was cloned and expressed in E. coli BL21 (DE3). The effects of glycine and Triton X-100 on extracellular production of α-cyclodextrin glycosyltransferase (α-CGTase) were investigated. When supplemented with Gly or Triton X-100 to the culture media individually, the secreted extracellular enzyme reached 32or 33 U/mL at 48 h of cultivation, respectively. When supplemented with Gly and Triton X-100 together, the extracellular α-CGTase activity reached 48 U/mL after 48 h cultivation, which was 20-fold of the control group without any additives. Analysis of membrane permeability demonstrated that addition of glycine and Triton X-100enhanced the permeability of both outer and inner membrane. The potential mechanism of the enhanced protein secretion was discussed.