Effect of substituting cao with bao on the viscosity and structure of cao‐bao‐sio2‐mgo‐al2o3 slags

Wang, Zhanjun,Sohn, Il Wiley-Blackwell 2018 Journal of the American Ceramic Society Vol.101 No.9

<P>In this study, the effect of CaO and BaO substitution on the viscosity and structure of CaO-BaO-SiO2-MgO-Al2O3 slags was investigated. The results showed that the viscosity increased with an increase in the BaO substitution concentration, which was correlated to an increase in the degree of polymerization (DOP) of the slag structural units as the activation energy increased from 207.9 to 263.8 kJ/mol for viscous flow. Deconvolution and area integration of the Raman spectrum of the slag revealed that the ratio of Q(3)/Q(2) (Q(i), i is the number of O-0 in a [SiO4]-tetrahedral unit) increased and NBO/Si (nonbridging oxygen per unit silicon atom) decreased with higher BaO content. It was also observed from the Al-27 magic angles pinning nuclear magnetic resonance (Al-27 MAS-NMR) spectrum that the relative proportion of Al-IV increased, while that of Al-V decreased because of the decrease in the percentage of nonbridging oxygen (O-), indicating the polymerization of the slag. O-1s X-ray photoelectron spectroscopy (XPS) was also carried out to semi-quantitatively analyze the various types of oxygen anions present in the slag. The XPS results correlated well with the results obtained from the analysis of the Raman and Al-27 MAS-NMR spectra of the slags and its viscous behavior.</P>

Cervical Cord Hemorrhage in Cerebral Cavernous Malformations

Wang Zhanjun,Wu Hao,Piao Yueshan,Wang Chaodong 대한신경과학회 2021 Journal of Clinical Neurology Vol.17 No.4

The effects of a short sequence enhancer (50-GTGAAATAAATGCAAATAAAGT) and its derived sequences on green fluorescent protein expression

Zhihong Ma,Zhanjun Lv,Xiu-Fang Wang,Xiangyang Jing,Jianjun Cheng 한국유전학회 2014 Genes & Genomics Vol.36 No.4

Cis-regulatory elements are regions of DNAthat regulate the expression of genes located on that samemolecule of DNA. Though these elements are important forgene expression regulation, the functions of cis elementsremain largely unknown. To explore the mechanisms ofgene activation by short sequence enhancers, we examinedthe enhancer activity of short sequence DNA and itsderived sequences using a GFP expression system. Wefound that AA sequence (50-GTGAAATAAATGCAAATAAAGT) induced strong GFP gene expression, while7pieA (50-GTGAAAAAAATGCAAAAAAAGT) did not. We mutated the five T bases of the AA sequence to A, C orG. Our findings indicated that sequences retaining the 7thand/or 17th Ts possessed strong enhancer activity. RT-PCRand RNA synthesis inhibition analysis using actinomycin Drevealed that the enhanced GFP gene expression inducedby the AA sequence occurred at the transcriptional level. To determine whether the AA sequence formed a secondarystructure via atypical complementation, PAGE methodwas used, and the results showed that the AA sequenceformed a secondary structure. Our results support previousevidence that AATAAA is an important composition of ciselements (enhancer/promoter), and suggest that the formationof an unstable stem-loop structure via atypicalcomplementation may be a new mechanism of enhanceractivity.

Probabilistic-based damage identification based on error functions with an autofocusing feature

Rahim Gorgin,Yunlong Ma,Zhanjun Wu,Dongyue Gao,Yishou Wang 국제구조공학회 2015 Smart Structures and Systems, An International Jou Vol.15 No.4

This study presents probabilistic-based damage identification technique for highlightingdamage in metallic structures. This technique utilizes distributed piezoelectric transducers to generate andmonitor the ultrasonic Lamb wave with narrowband frequency. Diagnostic signals were used to define thescatter signals of different paths. The energy of scatter signals till different times were calculated by takingroot mean square of the scatter signals. For each pair of parallel paths an error function based on the energyof scatter signals is introduced. The resultant error function then is used to estimate the probability of thepresence of damage in the monitoring area. The presented method with an autofocusing feature is applied toaluminum plates for method verification. The results identified using both simulation and experimentalLamb wave signals at different central frequencies agreed well with the actual situations, demonstrating thepotential of the presented algorithm for identification of damage in metallic structures. An obvious merit ofthe presented technique is that in addition to damages located inside the region between transducers; thosewho are outside this region can also be monitored without any interpretation of signals. This noveltyqualifies this method for online structural health monitoring.

Probabilistic-based damage identification based on error functions with an autofocusing feature

Gorgin, Rahim,Ma, Yunlong,Wu, Zhanjun,Gao, Dongyue,Wang, Yishou Techno-Press 2015 Smart Structures and Systems, An International Jou Vol.15 No.4

This study presents probabilistic-based damage identification technique for highlighting damage in metallic structures. This technique utilizes distributed piezoelectric transducers to generate and monitor the ultrasonic Lamb wave with narrowband frequency. Diagnostic signals were used to define the scatter signals of different paths. The energy of scatter signals till different times were calculated by taking root mean square of the scatter signals. For each pair of parallel paths an error function based on the energy of scatter signals is introduced. The resultant error function then is used to estimate the probability of the presence of damage in the monitoring area. The presented method with an autofocusing feature is applied to aluminum plates for method verification. The results identified using both simulation and experimental Lamb wave signals at different central frequencies agreed well with the actual situations, demonstrating the potential of the presented algorithm for identification of damage in metallic structures. An obvious merit of the presented technique is that in addition to damages located inside the region between transducers; those who are outside this region can also be monitored without any interpretation of signals. This novelty qualifies this method for online structural health monitoring.

Characterization of the effect of He⁺ irradiation on nanoporous-isotropic graphite for molten salt reactors

Zhang, Heyao,He, Zhao,Song, Jinliang,Liu, Zhanjun,Tang, Zhongfeng,Liu, Min,Wang, Yong,Liu, Xiangdong Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.6

Irradiation-induced damage of binderless nanoporous-isotropic graphite (NPIG) prepared by isostatic pressing of mesophase carbon microspheres for molten salt reactor was investigated by 3.0 MeV He⁺ irradiation at room temperature and high temperature of 600 ℃, and IG-110 was used as the comparation. SEM, TEM, X-ray diffraction and Raman spectrum are used to characterize the irradiation effect and the influence of temperature on graphite radiation damage. After irradiation at room temperature, the surface morphology is rougher, the increase of defect clusters makes atom flour bend, the layer spacing increases, and the catalytic graphitization phenomenon of NPIG is observed. However, the density of defects in high temperature environment decreases and other changes are not obvious. Mechanical properties also change due to changes in defects. In addition, SEM and Raman spectra of the cross section show that cracks appear in the depth range of the maximum irradiation dose, and the defect density increases with the increase of irradiation dose.

Preparation and BSA Adsorption Behavior of Chitosan-arginine Based Nanofiber Membranes

Xiaojie Li,Guiqun Chao,Liangan Wang,Xianlin Xu,Zhanjun Cai,Lei Shi,Xupin Zhuang,Bo-wen Cheng 한국섬유공학회 2018 Fibers and polymers Vol.19 No.5

In this work, an affinity nanofiber membrane was successfully prepared by solution blowing of arginine-modified chitosan (CS-Arg) for bovine serum albumin (BSA) adsorption. CS-Arg was firstly synthesized by coupling L-arginine onto chitosan backbone. Then, CS-Arg nanofiber membranes (CANFs) were fabricated using solution blowing process with Polylactide (PLA) as assistant polymer. The results showed that CANFs effectively adsorbed BSA, and the adsorption capacities were influenced by the degrees of substitution (DS) of arginine in CS, pH value, contact time, and initial protein concentration. The highest adsorption capacity of 445.19 mg/g was achieved uvnder the following conditions: DS of 43.7 %, pH of 7.14, and initial concentration of 3.0 mg/ml. BSA adsorbed on the CANFs membrane conformed to Langmuir model, and the adsorption rate was consistent with the second-order kinetics model. This work implies that an arginine-modified chitosan nanofiber-based novel biomaterial has a potential application in adsorption of BSA.

Presulfidation and activation mechanism of Mo/Al2O3 catalyst sulfided by ammonium thiosulfate

Mingxing Tang,Xuekuan Li,Hui Ge,Weibin Fan,Guofu Wang,Zhanjun Lyu 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.8

Mo/Al2O3 catalyst was presulfided with (NH4)2S2O3 to elucidate presulfidation and activation mechanism. Itis illustrated that the Mo oxide is firstly partially sulfided during presulfidation and then in situ reduced into MoS2−x inactivation, and finally sulfided to active state during hydrodesulfurization (HDS). A synergistic effect between the S2− andS6+ ions in (NH4)2S2O3 produces a positive influence on the HDS performance. The S2− ions contribute to the sulfidationof Mo ions, while the S6+ species interact with Al2O3 support, weakening the interaction of active species with support.

Plant cover associated with aboveground net primary productivity (ANPP) mediates insect community composition in steppes of Northwest China

Zi-Hua Zhao,Gadi V.P. Reddy,Shuhua Wei,Mengmeng Zhu,Kaiyang Zhang,Hongqian Yu,Zhanjun Wang,Qi Jiang,Rong Zhang 한국응용곤충학회 2018 Journal of Asia-Pacific Entomology Vol.21 No.1

Temperate steppe is one of the most important natural habitats for the conservation of arthropod and birdbiodiversity across the Eurasian Tectonic Plate. Since 1950, fragmentation of the steppe habitat has caused a lossof biodiversity and degradation of the species communities found in natural steppe. Therefore, in this study, bothplants and insects were sampled at 56 sites in the steppe biome of northwestern China to explore the effects ofplant community on insect community composition and diversity. The insect community structure varied in thefour different steppe types (meadow steppe, typical steppe, desert steppe, and steppe desert). Plant cover (diversity)was an important driving force, which could enhance number of families and abundance of an insectcommunity. Aboveground net primary productivity and water content of plants had no significant effects oninsect community, although the plant community as a whole did mediate insect composition and communitystructure. Future research should explore the ecological role of particular functional groups in plant and insectcommunities. Supplemental sowing to improve plant diversity in steppe habitat may be another strategy toenhance biodiversity and achieve sustainable management.