Effect of oxidizing treatment on electrocatalytic activity of boron-doped amorphous carbon thin films

Wang Chen-Song,Suo Ni,Huang Hao,Wu Ai-min,Cao Guo-Zhong,Zhang Gui-Feng 한국탄소학회 2019 Carbon Letters Vol.29 No.5

Boron-doped amorphous carbon (BDAC) thin films with a regular oxygen reduction reaction (ORR) catalytic activity were synthesized in a hot filament chemical vapor deposition device using a mixture of CH4 and H2 as a gas source and B2O3 as a boron source and then oxidized in air at 380–470 °C for 15–75 min. Scanning electron microscope, transmission electron microscope, Raman spectroscopy, X-ray photoelectron spectroscopy, and electrochemical tests were used to characterize the physical and electrochemical properties of the BDAC catalysts. It was concluded that the BDAC catalyst oxidized at 450 °C for 45 min showed the best ORR catalytic activity in alkaline medium. The oxygen reduction potential and the transfer electron number n, respectively, are − 0.286 V versus Ag/AgCl and 3.24 from the rotating disk electrode experiments. The treated carbon film has better methanol resistance and stability than the commercial Pt/C catalyst.

Effect of oxidizing treatment on electrocatalytic activity of boron‑doped amorphous carbon thin films

Chen‑Song Wang,Ni Suo,Hao Huang,Ai‑min Wu,Guo‑Zhong Cao,Gui‑Feng Zhang 한국탄소학회 2019 Carbon Letters Vol.29 No.5

Boron-doped amorphous carbon (BDAC) thin films with a regular oxygen reduction reaction (ORR) catalytic activity were synthesized in a hot filament chemical vapor deposition device using a mixture of CH4 and H2 as a gas source and B2O3 as a boron source and then oxidized in air at 380–470 °C for 15–75 min. Scanning electron microscope, transmission electron microscope, Raman spectroscopy, X-ray photoelectron spectroscopy, and electrochemical tests were used to characterize the physical and electrochemical properties of the BDAC catalysts. It was concluded that the BDAC catalyst oxidized at 450 °C for 45 min showed the best ORR catalytic activity in alkaline medium. The oxygen reduction potential and the transfer electron number n, respectively, are − 0.286 V versus Ag/AgCl and 3.24 from the rotating disk electrode experiments. The treated carbon film has better methanol resistance and stability than the commercial Pt/C catalyst.

Regular Closed Boolean Algebra in Space with One Point Lindeloffication Topology

Cao, Shang Min 한국수학교육학회 2000 純粹 및 應用數學 Vol.7 No.1

Let (X^*, τ^* ) be the space with one point Lindelo¨ffication topology of space (X, τ). This paper offers the definition of the space with one point Lindelo¨ffication topology of a topological space and proves that the retraction regular closed function f : K^*(X^*) → K(X) defined by f(A^*) = A^* if p ◎ A^* or f (A^*) = A^* - {p} if p ∈ A^* is a homomorphism. There are two examples in this paper to show that the retraction regular closed function f is neither a surjection nor an injection.

Synthesis of 2,5-Furandicarboxylic Acid-Based Heat-Resistant Polyamides Under Existing Industrialization Process

Min Cao,Chuanhui Zhang,Bo He,Mujun Huang,Sujun Jiang 한국고분자학회 2017 Macromolecular Research Vol.25 No.7

As a bio-based material, 2,5-furandicarboxylic acid (FDCA) has been used widely as alternative material to terephthalic acid to produce polyesters or polyamides. In this study, PA10T/10F with melting point higher than 280 oC was produced under existing industrialization process (prepolymerization+solid state polymerization (SSP)), viscosity of which was affected greately by decarboxylation of FDCA. TGIR technique was used to study decarboxylation, and 1,10-decanediamine, CO2, H2O and furan derivates can be found, verifying decarboxylation scheme. 1H NMR, 13C NMR and 2D NMR analysis showed that nearly half of the feeding FDCA monomers decarboxylates during SSP, instead of entering the polyamide chain, leading to the lower furan moiety ratio in polymers compared to that of feeding ratio. However, thermal stability of PA10T/10F polyamide is comparable to PA10T homopolymer, which indicates that FDCA can be a promising base material for heat-resistant polyamide production.

REGULAR CLOSED BOOLEAN ALGEBRA IN THE SPACE WITH EXTENSION TOPOLOGY

Cao, Shang Min 한국수학교육학회 2000 純粹 및 應用數學 Vol.7 No.2

Any Hausdorff space on a set which has at least two points has a regular closed Boolean algebra different from the indiscrete regular closed Boolean algebra as indiscrete space. The Sierpinski space and the space with finite complement topology on any infinite set etc. do the same. However, there is To space which does the same with Hausdorff space as above. The regular closed Boolean algebra in a topological space is isomorphic to that algebra in the space with its open extension topology.

Numerical Simulation of Hot-Carrier Gate and Injection Current in Deep-Submicron Thin-Film SOI/MOSFET Using Exact Field Distribution

Cao,Jain Min,Wu,Chuan Liang,Shen,Wen ZhEng,Huang,Chang,Li,Yin Bo,Xu,Yang Zhen 대한전자공학회 1997 ICVC : International Conference on VLSI and CAD Vol.5 No.1

Start with 2D simulation of hot-carrier injection current. in this pier, we have discussed the influence of different silicon film thickness (Tsi), gate oxide thickness (Tox1) and substrate doping (Na) an the hot-carrier effects of thin-film deep submicron SOI/MOSFET. Simulation results indicate that, with reduction of Tsi, the hot-carrier current is reduced (by more than 2 orders); and in Tsi range of 0.05-0.1μ. the hot carrier carrent is smallest and insensitive to Tox1, Na and Tsi. These are helpful to the design of high reliability SOI/MOSFET.

Functional Definition of LuxS, an Autoinducer-2 (AI-2) Synthase and Its Role in Full Virulence of Streptococcus suis Serotype 2

Min Cao,Youjun Feng,Changjun Wang,Feng Zheng,Ming Li,Hui Liao,Yinghua Mao,Xiuzhen Pan,Jing Wang,Dan Hu,Fuquan Hu,Jiaqi Tang 한국미생물학회 2011 The journal of microbiology Vol.49 No.6

Quorum sensing is a widespread chemical communication in response to fluctuation of bacterial population density, and has been implicated into bacterial biofilm formation and regulation of expression of virulence factors. The luxS gene product, S-ribosylhomocysteinase, catalizes the last committed step in biosynthetic pathway of autoinducer 2 (AI-2), a signaling molecule for inter-species quorum sensing. We found a luxS homologue in 05ZYH33, an epidemic strain of Streptococcus suis serotype 2 (SS2) in China. A luxS null mutant (ΔluxS) of 05ZYH33 strain was obtained using an approach of homologous recombination. LuxS was determined to be required for AI-2 production in 05ZYH33 strain of S. suis 2. Inactivation of luxS gene led to a wide range of phenotypic changes including thinner capsular walls, increased tolerance to H_2O_2, reduced adherence capacity to epithelial cells, etc. In particular, loss of LuxS impaired dramatically its full virulence of SS2 in experimental model of piglets, and functional complementation restored it nearly to the level of parent strain. Genome-wide transcriptome analyses suggested that some known virulence factors such as CPS are down-regulated in the ΔluxS mutant, which might in part explain virulence attenuation by luxS deletion. Similarly, 29 of 71 genes with different expression level were proposed to be targets candidate regulated by LuxS/AI-2-dependent quorum sensing.

Research on an Anchor Point Lever Beam Coupling Type Tuning Fork Micro-gyroscope

Lian-min Cao,Jian-wei Li,Xian-wen Liu,Feng-yao Sun 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.6

This paper has designed an anchor point lever beam coupled tuning fork micro-gyroscope and tested its output performance. The tuning fork micro-gyro is designed to eliminate the output error caused by orthogonal coupling and in-phase-inverting coupling by structural decoupling and electrical decoupling, and can improve the anti-vibration performance and the modal optimization ability. It has derived the dynamic response working model of the non-ideal tuning fork micro-gyroscope, and optimized the structural parameters of the micro-gyroscope by simulation analysis. The microstructure processing has been realized by the SOI-MEMS process, sealed the processed structural prototype, and tested the performance through the established experimental system. According to the test results, the designed micro-gyroscope driving direction has greatly reduced the in-phase-inverting coupling through the anchor coupling lever beam, and the detection direction eff ectively suppressed the in-phase-inverting coupling through the stiff ness matching electrode. While closed-loop detecting, the measured Aallan variance zero-bias stability is 1.779°/h, and the 1σ zero-bias stability is 8.3°/h. While applying a stiff ness matching voltage, the measured vibration sensitivity is 23.9°/h/g.

Research on Output Characteristics of Double-Ended Fixed Beam Piezoelectric Energy Harvester Under Random Excitation

Lian-min Cao,Yong Cai,Guotai Xu,Jiulong Cui 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.6

By use of the concept of impedance, this paper establishes a random energy harvester output model of double-ended fi xed beam piezoelectric energy harvester under random White Gaussian noise excitation, which is based on the discussion of the output characteristics infl uenced by changing vibration beam shape and piezoelectric sheet length under random excitation, while improving piezoelectric structure of double-ended fi xed beam piezoelectric energy harvester. It also deduces the output voltage, current and power of energy harvester with Fokker–Planck equation, which are verifi ed by Monte Carlo simulation and experimental testing. It can be found that improving vibration beam shape can reduce resonant frequency and increase average output power of the system. The optimal value of piezoelectric sheet length can be diff erent corresponding to diff erent structures, which proves that double-ended fi xed beam piezoelectric energy harvester under random White Gaussian noise excitation can achieve maximum output with optimal piezoelectric sheet length. In addition, in order to further improve the output performance of piezoelectric energy harvester under random excitation, it is necessary to increase the acceleration spectral density under random excitation and set an optimal value of the piezoelectric loading resistance, which is more suitable for energy harvester applied under random low-frequency environment.

Design and Test of the MEMS Coupled Piezoelectric- Electromagnetic Energy Harvester

Lian-min Cao,Zhi-xu Li,Cheng Guo,Peng-peng Li,Xiang-qiang Meng,Ting-ming Wang 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.4

This paper researches on the design and test of the output performance of double-end clamped MEMS coupled piezoelectric–electromagnetic energy harvester. It establishes the theoretical output model of the double-end clamped rectangular beam and trapezoidal beam piezoelectric–electromagnetic energy harvester, and optimizes the structure parameters of piezoelectric and electromagnetic unit with simulation analysis. It also respectively realizes the processing of piezoelectric and electromagnetic unit by MEMS and flexible PCB technology, and completes the performance test of structure prototype through the experimental system. The result showed that the capacity of MEMS coupled piezoelectric–electromagnetic energy harvester, which taked four coil piezoelectric with integrated electromagnetic in series, was 12.23 times higher than that of piezoelectric energy harvester. Also the output voltage and power of coupled trapezoidal beam energy harvester were respectively increased 18.89% and 2.26%, compared with coupled rectangular beam energy harvester.