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光催化 3

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深度学习 2

过氧化氢 2

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H∞控制;零和动态博弈;强化学习;自适应动态规划;极小极大Q-学习;策略迭代 1

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Nonlinear dynamic analysis for elastic robotic arms

H. KORAYEM, H. N. RAHIMI

《机械工程前沿(英文)》 2011年 第6卷 第2期   页码 219-228 doi: 10.1007/s11465-011-0218-y

摘要:

The aim of the paper is to analyze the nonlinear dynamics of robotic arms with elastic links and joints. The main contribution of the paper is the comparative assessment of assumed modes and finite element methods as more convenient approaches for computing the nonlinear dynamic of robotic systems. Numerical simulations comprising both methods are carried out and results are discussed. Hence, advantages and disadvantages of each method are illustrated. Then, adding the joint flexibility to the system is dealt with and the obtained model is demonstrated. Finally, a brief description of the optimal motion generation is presented and the simulation is carried out to investigate the role of robot dynamic modeling in the control of robots.

关键词: robotic arms     elastic link     elastic joint     nonlinear dynamics     optimal control    

Endemicity of H9N2 and H5N1 avian influenza viruses in poultry in China poses a serious threat to poultry

Jiao HU,Xiufan LIU

《农业科学与工程前沿(英文)》 2016年 第3卷 第1期   页码 11-24 doi: 10.15302/J-FASE-2016092

摘要: The H9N2 and H5N1 avian influenza viruses (AIVs) have been circulating in poultry in China and become endemic since 1998 and 2004, respectively. Currently, they are prevalent in poultry throughout China. This endemicity makes them actively involved in the emergence of the novel lineages of other subtypes of influenza viruses, such as the well-known viruses of the highly pathogenic avian influenza (HPAI) H5N2 and the 2013 novel H7N7, H7N9 and H10N8 subtypes, thereby threatening both the poultry industry and public health. Here, we will review briefly the prevalence and evolution, pathogenicity, transmission, and disease control of these two subtypes and also discuss the possibility of emergence of potentially virulent and highly transmissible AIVs to humans.

关键词: avian influenza virus     H9N2     H5N1     novel viruses     public health    

Development progress of China’s 600 km/h high-speed magnetic levitation train

《工程管理前沿(英文)》 2022年 第9卷 第3期   页码 509-515 doi: 10.1007/s42524-022-0199-z

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关键词: 600 km/h high-speed magnetic levitation train     development history     technological innovation    

growth of a-few-layered MoS on CdS nanorod for high efficient photocatalytic H production

《能源前沿(英文)》 2021年 第15卷 第3期   页码 752-759 doi: 10.1007/s11708-021-0779-3

摘要: An ultrathin MoS2 was grown on CdS nanorod by a solid state method using sulfur powder as sulfur source for photocatalytic H2 production. The characterization result reveals that the ultrathin MoS2 nanosheets loaded on CdS has a good contact state. The photoelectrochemical result shows that MoS2 not only are beneficial for charge separation, but also works as active sites, thus enhancing photocatalytic activity. Compared with pure CdS, the photocatalytic activity of MoS2 loaded CdS was significantly improved. The hydrogen evolution rate on m(MoS2): m(CdS) = 1: 50 (m is mass) reaches 542 μmol/h, which is 6 times of that on pure CdS (92 μmol/h). This work provides a new design for photocatalysts with high photocatalytic activities and provides a deeper understanding of the effect of MoS2 on enhancing photocatalytic activity.

关键词: photocatalytic H2 production     CdS     MoS2 cocatalyst     charge separation    

Probes and nano-delivery systems targeting NAD(P)H:quinone oxidoreductase 1: a mini-review

《化学科学与工程前沿(英文)》 2023年 第17卷 第2期   页码 123-138 doi: 10.1007/s11705-022-2194-7

摘要: The two-electron cytoplasmic reductase NAD(P)H:quinone oxidoreductase 1 is expressed in many tissues. NAD(P)H:quinone oxidoreductase 1 is well-known for being highly expressed in most cancers. Therefore, it could be a target for cancer therapy. Because it is a quinone reductase, many bioimaging probes based on quinone structures target NAD(P)H:quinone oxidoreductase 1 to diagnose tumours. Its expression is higher in tumours than in normal tissues, and using target drugs such as β-lapachone to reduce side effects in normal tissues can help. However, the physicochemical properties of β-lapachone limit its application. The problem can be solved by using nanosystems to deliver β-lapachone. This mini-review summarizes quinone-based fluorescent, near-infrared and two-photon fluorescent probes, as well as nanosystems for delivering the NAD(P)H:quinone oxidoreductase 1-activating drug β-lapachone. This review provides valuable information for the future development of probes and nano-delivery systems that target NAD(P)H:quinone oxidoreductase 1.

关键词: NAD(P)H:quinone oxidoreductase 1     cancer therapy     target     probe     nanosystem    

Influence of short chain ceramides and lipophilic penetration enhancers on the nano-structure of stratum corneum model membranes studied using neutron diffraction

Annett SCHROETER, Tanja ENGELBRECHT, Reinhard H. H. NEUBERT

《化学科学与工程前沿(英文)》 2013年 第7卷 第1期   页码 29-36 doi: 10.1007/s11705-013-1302-0

摘要: Oriented stratum corneum model lipid membranes were used to study the influence of the short chain ceramides (CER)[NP] and [AP] as well as the impact of the lipophilic penetration enhancer molecules oleic acid (OA) and isopropyl myristate (IPM) on the lipid nanostructure. The influence of the enhancer molecules were studied using specifically deuterated OA and IPM and neutron diffraction. H NMR spectroscopy was used to study the impact of the ceramides’ degree of order within the stratum corneum model lipid membranes. It was found that CER[NP] forms two very stable phases with high resistance against temperature increase. Phase B showed unusual hydration behavior as no water uptake of this phase was observed. The H NMR spectroscopic measurements showed that CER[NP] based ternary model system had a higher state of lamellar order in comparison to CER[AP] based lipid matrix. The studies confirmed that the short chain ceramides, particularly CER[NP], have a very high impact on the integrity of the Stratum corneum lipid bilayers. The penetration enhancer OA has not influenced the repeat distance of the model membrane based on CER[AP], and was not able to induce a phase separation in the investigated lipid matrix. However, a disorder and a fluidisation of the model membranes were observed when OA was incorporated. IPM showed the same effect but two phases (assigned as phase A and B) appeared, when IPM was used as penetration enhancer and incorporated into the model membrane. Furthermore, two arrangements of IPM were identified in phase A using deuterated IPM. A model of the nanostructure of the Stratum corneum lipid membranes is presented.

关键词: nano-structure of the stratum corneum     ceramide     penetration enhancer     model membrane     neutron diffraction     2H NMR spectroscopy    

A new technique for islanding operation of distribution network connected with mini hydro

LAGHARI,H. MOKHLIS,M. KARIMI,A. H. A. BAKAR,Hasmaini MOHAMAD

《信息与电子工程前沿(英文)》 2015年 第16卷 第5期   页码 418-427 doi: 10.1631/FITEE.1400309

摘要: An islanding operation of a distribution network is a topic of interest due to the significant penetration of distributed generation (DG) in a power system network. However, controlling the frequency of an islanded distribution system remains an unresolved issue, especially when the load exceeds the generation. This paper presents a new technique for a successful islanding operation of a distribution network connected with multiple mini hydro based DGs. The proposed technique is based on three main parts. The first part uses an islanding detection technique to detect the islanding event correctly. The second part consists of a power imbalance estimation module (PIEM), which determines the power imbalance between the generation and load demand. The third part consists of a load shedding controller, which receives the power imbalance value and performs load shedding according to load priority. The proposed technique is validated on an 11 kV existing Malaysia distribution network. The simulation results show that the proposed technique is effective in performing a successful islanding operation by shedding a significant number of loads.

关键词: Islanding operation     Mini hydro     Distributed generation (DG)     Islanding detection     Load shedding    

Plasma enhanced chemical vapor deposition of excellent a-Si:H passivation layers for a-Si:H/c-Si heterojunction

Lei ZHAO,Wenbin ZHANG,Jingwei CHEN,Hongwei DIAO,Qi WANG,Wenjing WANG

《能源前沿(英文)》 2017年 第11卷 第1期   页码 85-91 doi: 10.1007/s11708-016-0437-3

摘要: The intrinsic a-Si:H passivation layer inserted between the doped a-Si:H layer and the c-Si substrate is very crucial for improving the performance of the a-Si:H/c-Si heterojunction (SHJ) solar cell. The passivation performance of the a-Si:H layer is strongly dependent on its microstructure. Usually, the compact a-Si:H deposited near the transition from the amorphous phase to the nanocrystalline phase by plasma enhanced chemical vapor deposition (PECVD) can provide excellent passivation. However, at the low deposition pressure and low deposition power, such an a-Si:H layer can be only prepared in a narrow region. The deposition condition must be controlled very carefully. In this paper, intrinsic a-Si:H layers were prepared on n-type Cz c-Si substrates by 27.12 MHz PECVD at a high deposition pressure and high deposition power. The corresponding passivation performance on c-Si was investigated by minority carrier lifetime measurement. It was found that an excellent a-Si:H passivation layer could be obtained in a very wide deposition pressure and power region. Such wide process window would be very beneficial for improving the uniformity and the yield for the solar cell fabrication. The a-Si:H layer microstructure was further investigated by Raman and Fourier transform infrared (FTIR) spectroscopy characterization. The correlation between the microstructure and the passivation performance was revealed. According to the above findings, the a-Si:H passivation performance was optimized more elaborately. Finally, a large-area SHJ solar cell with an efficiency of 22.25% was fabricated on the commercial 156 mm pseudo-square n-type Cz c-Si substrate with the open-circuit voltage ( ) of up to 0.732 V.

关键词: PECVD     high pressure and high power     a-Si:H microstructure     passivation     heterojunction solar cell    

Research progress on human infection with avian influenza H7N9

Xiaoxin Wu, Lanlan Xiao, Lanjuan Li

《医学前沿(英文)》 2020年 第14卷 第1期   页码 8-20 doi: 10.1007/s11684-020-0739-z

摘要: Since the first case of novel H7N9 infection was reported, China has experienced five epidemics of H7N9. During the fifth wave, a highly pathogenic H7N9 strain emerged. Meanwhile, the H7N9 virus continues to accumulate mutations, and its affinity for the human respiratory epithelial sialic acid 2-6 receptor has increased. Therefore, a pandemic is still possible. In the past 6 years, we have accumulated rich experience in dealing with H7N9, especially in terms of virus tracing, epidemiological research, key site mutation monitoring, critical disease mechanisms, clinical treatment, and vaccine development. In the research fields above, significant progress has been made to effectively control the spread of the epidemic and reduce the fatality rate. To fully document the research progress concerning H7N9, we reviewed the clinical and epidemiological characteristics of H7N9, the key gene mutations of the virus, and H7N9 vaccine, thus providing a scientific basis for further monitoring and prevention of H7N9 influenza epidemics.

关键词: H7N9     pandemic     epidemiology     mutations     vaccine     influenza    

Photoelectrocatalytic generation of H and S from toxic HS by using a novel BiOI/WO nanoflake array photoanode

《能源前沿(英文)》 2021年 第15卷 第3期   页码 744-751 doi: 10.1007/s11708-021-0775-7

摘要: In this paper, a photoelectrocatalytic (PEC) recovery of toxic H2S into H2 and S system was proposed using a novel bismuth oxyiodide (BiOI)/ tungsten trioxide (WO3) nano-flake arrays (NFA) photoanode. The BiOI/WO3 NFA with a vertically aligned nanostructure were uniformly prepared on the conductive substrate via transformation of tungstate following an impregnating hydroxylation of BiI3. Compared to pure WO3 NFA, the BiOI/WO3 NFA promotes a significant increase of photocurrent by 200%. Owing to the excellent stability and photoactivity of the BiOI/WO3 NFA photoanode and I/I 3 catalytic system, the PEC system toward splitting of H2S totally converted S2– into S without any polysulfide ( Sx n) under solar-light irradiation. Moreover, H2 was simultaneously generated at a rate of about 0.867 mL/(h·cm). The proposed PEC H2S splitting system provides an efficient and sustainable route to recover H2 and S.

关键词: bismuth oxyiodide (BiOI)/ tungsten trioxide (WO3) nano-flake arrays (NFA)     photoelectrocatalytic (PEC)     H2S splitting     H2     S    

Anovel approach of noise statistics estimate using H∞ filter in target tracking

Xie WANG,Mei-qin LIU,Zhen FAN,Sen-lin ZHANG

《信息与电子工程前沿(英文)》 2016年 第17卷 第5期   页码 449-457 doi: 10.1631/FITEE.1500262

摘要: Noise statistics are essential for estimation performance. In practical situations, however, a priori information of noise statistics is often imperfect. Previous work on noise statistics identification in linear systems still requires initial prior knowledge of the noise. A novel approach is presented in this paper to solve this paradox. First, we apply the H∞ filter to obtain the system state estimates without the common assumptions about the noise in conventional adaptive filters. Then by applying state estimates obtained from the H∞ filter, better estimates of the noise mean and covariance can be achieved, which can improve the performance of estimation. The proposed approach makes the best use of the system knowledge without a priori information with modest computation cost, which makes it possible to be applied online. Finally, numerical examples are presented to show the efficiency of this approach.

关键词: Noise estimate     H∞     filter     Target tracking    

Analysis of the double-layer α-Si:H emitter with different doping concentrations for α-Si:H/c-Si heterojunction

Haibin HUANG,Gangyu TIAN,Tao WANG,Chao GAO,Jiren YUAN,Zhihao YUE,Lang ZHOU

《能源前沿(英文)》 2017年 第11卷 第1期   页码 92-95 doi: 10.1007/s11708-016-0432-8

摘要: Double-layer emitters with different doping concentrations (DLE) have been designed and prepared for amorphous silicon/crystalline silicon (α-Si:H/c-Si) heterojunction solar cells. Compared with the traditional single layer emitter, both the experiment and the simulation (AFORS-HET, http://www.paper.edu.cn/html/releasepaper/2014/04/282/) prove that the double-layer emitter increases the short circuit current of the cells significantly. Based on the quantum efficiency (QE) results and the current-voltage-temperature analysis, the mechanism for the experimental results above has been investigated. The possible reasons for the increased current include the enhancement of the QE in the short wavelength range, the increase of the tunneling probability of the current transport and the decrease of the activation energy of the emitter layers.

关键词: double-layer emitter     α-Si:H/c-Si heterojunction solar cell     short circuit current     quantum efficiency     current-voltage-temperature    

grown TiN/N-TiO composite for enhanced photocatalytic H evolution activity

《能源前沿(英文)》 2021年 第15卷 第3期   页码 721-731 doi: 10.1007/s11708-021-0766-8

摘要: Titanium nitride (TiN) decorated N-doped titania (N-TiO2) composite (TiN/N-TiO2) is fabricated via an in situ nitridation using a hydrothermally synthesized TiO2 and melamine (MA) as raw materials. After the optimization of the reaction condition, the resultant TiN/N-TiO2 composite delivers a hydrogen evolution activity of up to 703 μmol/h under the full spectrum irradiation of Xe-lamp, which is approximately 2.6 and 32.0 times more than that of TiO2 and TiN alone, respectively. To explore the underlying photocatalytic mechanism, the crystal phase, morphology, light absorption, energy band structure, element composition, and electrochemical behavior of the composite material are characterized and analyzed. The results indicate that the superior activity is mainly caused by the in situ formation of plasmonic TiN and N-TiO2 with intimate interface contact, which not only extends the spectral response range, but also accelerates the transfer and separation of the photoexcited hot charge carrier of TiN. The present study provides a fascinating approach to in situ forming nonmetallic plasmonic material/N-doped TiO2 composite photocatalysts for high-efficiency water splitting.

关键词: photocatalytic H2 evolution     TiN/N-TiO2 composite     plasmonic effect     in-situ nitridation    

density functional theory study of methane activation on MgO supported NiM cluster: role of M on C–H

《化学科学与工程前沿(英文)》 2022年 第16卷 第10期   页码 1485-1492 doi: 10.1007/s11705-022-2169-8

摘要: Methane activation is a pivotal step in the application of natural gas converting into high-value added chemicals via methane steam/dry reforming reactions. Ni element was found to be the most widely used catalyst. In present work, methane activation on MgO supported Ni–M (M = Fe, Co, Cu, Pd, Pt) cluster was explored through detailed density functional theory calculations, compared to pure Ni cluster. CH4 adsorption on Cu promoted Ni cluster requires overcoming an energy of 0.07 eV, indicating that it is slightly endothermic and unfavored to occur, while the adsorption energies of other promoters M (M = Fe, Co, Pd and Pt) are all higher than that of pure Ni cluster. The role of M on the first C–H bond cleavage of CH4 was investigated. Doping elements of the same period in Ni cluster, such as Fe, Co and Cu, for C–H bond activation follows the trend of the decrease of metal atom radius. As a result, Ni–Fe shows the best ability for C–H bond cleavage. In addition, doping the elements of the same family, like Pd and Pt, for CH4 activation is according to the increase of metal atom radius. Consequently, C–H bond activation demands a lower energy barrier on Ni–Pt cluster. To illustrate the adsorptive dissociation behaviors of CH4 at different Ni–M clusters, the Mulliken atomic charge was analyzed. In general, the electron gain of CH4 binding at different Ni–M clusters follows the sequence of Ni–Cu (–0.02 e) < Ni (–0.04 e) < Ni–Pd (–0.08 e) < Ni–Pt (–0.09 e) < Ni–Co (–0.10 e) < Ni–Fe (–0.12 e), and the binding strength between catalysts and CH 4 raises with the CH4 electron gain increasing. This work provides insights into understanding the role of promoter metal M on thermal-catalytic activation of CH4 over Ni/MgO catalysts, and is useful to interpret the reaction at an atomic scale.

关键词: CH4 dissociation     Ni–M     C–H bond activation     charge transfer    

The effect of doping and steam treatment on the catalytic activities of nano-scale H-ZSM-5 in the methanol

Baodong Song, Yongqiang Li, Gang Cao, Zhenhai Sun, Xu Han

《化学科学与工程前沿(英文)》 2017年 第11卷 第4期   页码 564-574 doi: 10.1007/s11705-017-1654-y

摘要: In the transformation of methanol to gasoline (MTG), the selectivity to gasoline and the aromatic content in the produced gasoline are important factors. The catalytic activities of steam-treated and non-steam-treated nano-scale H-ZSM-5 (NHZ5) catalysts impregnated with Ag(I), Zn(II) or P(V) have been investigated in a continuous flow fixed bed reactor. The NH -TPD results showed that after impregnation, the Ag/NHZ5, Zn/NHZ5 and P/NHZ5 catalysts contained comparatively more strong, medium-strong and weak acid sites, respectively. Treatment with steam decreased the number of acid sites in all the catalysts, but the pore volumes in the catalysts were larger which improved carbon deposition resistance resulting in prolonged lifetimes. After 6 h of MTG reaction, the selectivity to gasoline for the steam-treated catalysts, , and were 70.5, 68.4 and 68.7 wt-%, respectively, whereas their respective aromatic contents in the produced gasoline were 61.9, 55.4 and 39.0 wt-%. Thus is the most promising catalyst for MTG applications which can meet the China IV gasoline standard that the amount of aromatics in gasoline should be less than 48 wt-%.

关键词: MTG     nano-scale H-ZSM-5     steam treatment     gasoline     selectivity to gasoline    

标题 作者 时间 类型 操作

Nonlinear dynamic analysis for elastic robotic arms

H. KORAYEM, H. N. RAHIMI

期刊论文

Endemicity of H9N2 and H5N1 avian influenza viruses in poultry in China poses a serious threat to poultry

Jiao HU,Xiufan LIU

期刊论文

Development progress of China’s 600 km/h high-speed magnetic levitation train

期刊论文

growth of a-few-layered MoS on CdS nanorod for high efficient photocatalytic H production

期刊论文

Probes and nano-delivery systems targeting NAD(P)H:quinone oxidoreductase 1: a mini-review

期刊论文

Influence of short chain ceramides and lipophilic penetration enhancers on the nano-structure of stratum corneum model membranes studied using neutron diffraction

Annett SCHROETER, Tanja ENGELBRECHT, Reinhard H. H. NEUBERT

期刊论文

A new technique for islanding operation of distribution network connected with mini hydro

LAGHARI,H. MOKHLIS,M. KARIMI,A. H. A. BAKAR,Hasmaini MOHAMAD

期刊论文

Plasma enhanced chemical vapor deposition of excellent a-Si:H passivation layers for a-Si:H/c-Si heterojunction

Lei ZHAO,Wenbin ZHANG,Jingwei CHEN,Hongwei DIAO,Qi WANG,Wenjing WANG

期刊论文

Research progress on human infection with avian influenza H7N9

Xiaoxin Wu, Lanlan Xiao, Lanjuan Li

期刊论文

Photoelectrocatalytic generation of H and S from toxic HS by using a novel BiOI/WO nanoflake array photoanode

期刊论文

Anovel approach of noise statistics estimate using H∞ filter in target tracking

Xie WANG,Mei-qin LIU,Zhen FAN,Sen-lin ZHANG

期刊论文

Analysis of the double-layer α-Si:H emitter with different doping concentrations for α-Si:H/c-Si heterojunction

Haibin HUANG,Gangyu TIAN,Tao WANG,Chao GAO,Jiren YUAN,Zhihao YUE,Lang ZHOU

期刊论文

grown TiN/N-TiO composite for enhanced photocatalytic H evolution activity

期刊论文

density functional theory study of methane activation on MgO supported NiM cluster: role of M on C–H

期刊论文

The effect of doping and steam treatment on the catalytic activities of nano-scale H-ZSM-5 in the methanol

Baodong Song, Yongqiang Li, Gang Cao, Zhenhai Sun, Xu Han

期刊论文