Saturation, Relaxation, and Dissociation of Excited Triplet Excitons in Conjugated Polymers

Yang, Xudong,Lee, Chang-Lyoul,Westenhoff, Sebastian,Zhang, Xinping,Greenham, Neil C. WILEY-VCH Verlag 2009 ADVANCED MATERIALS Vol.21 No.8

<B>Graphic Abstract</B> <P>Femtosecond pump-probe spectroscopy is used to measure the excited state absorption dynamics in triplet excitons generated by continuous wave excitation of a conjugated polymer. Saturation of the T<SUB>1</SUB>–T<SUB>n</SUB> transition is observed, allowing a cross-section of 2.0 × 10<SUP>−16</SUP> cm<SUP>2</SUP> to be established. Relaxation to T<SUB>1</SUB> occurs with a 300 fs timescale, but 20% of T<SUB>n</SUB> states dissociate into charges. <img src='wiley_img/09359648-2009-21-8-ADMA200802597-content.gif' alt='wiley_img/09359648-2009-21-8-ADMA200802597-content'> </P>

Percutaneous endoscopic gastrostomy

Xudong Liu,Zhengqiang Yang,Shun He,Guiqi Wang 소화기인터벤션의학회 2021 Gastrointestinal Intervention Vol.10 No.2

Percutaneous endoscopic gastrostomy (PEG) is a feasible and safe technique for patients who need long-term feeding and cannot eat orally. With the increasing maturity of PEG technique, a large number of patients receive PEG tube placement every year in the world. However, PEG tube placement is not necessary in some patients, and some other patients are not evaluated strictly, leading to serious complications. In a broad sense, the mainly two indications for PEG include long-term enteral nutrition and gastric decompression. On the other hand, the main contraindications of PEG are distal intestinal obstruction, severe coagulation abnormalities, and severe infection at the PEG site. In the first section of this review, the indications and contraindications of PEG are introduced. Although PEG tube placement is a relatively safe technique, it can still cause a number of complications, including minor and major complications. Through standard management and treatment, the outcome of most patients is very good. In the second section of this review, we describe a variety of minor and major tube-related complications, and the treatment and prevention of these complications. In addition, the preparation and post-insertion care are also very important for PEG, which can reduce the incidence of complications. In the last section of this review, we describe related issues about the preparation and post-insertion care of PEG. In conclusion, PEG tube placement is a widely accepted technique that can bring benefits to the right patients.

Percutaneous endoscopic gastrostomy

Xudong Liu,Zhengqiang Yang,Shun He,Guiqi Wang 소화기인터벤션의학회 2021 International journal of gastrointestinal interven Vol.10 No.2

Percutaneous endoscopic gastrostomy (PEG) is a feasible and safe technique for patients who need long-term feeding and cannot eat orally. With the increasing maturity of PEG technique, a large number of patients receive PEG tube placement every year in the world. However, PEG tube placement is not necessary in some patients, and some other patients are not evaluated strictly, leading to serious complications. In a broad sense, the mainly two indications for PEG include long-term enteral nutrition and gastric decompression. On the other hand, the main contraindications of PEG are distal intestinal obstruction, severe coagulation abnormalities, and severe infection at the PEG site. In the first section of this review, the indications and contraindications of PEG are introduced. Although PEG tube placement is a relatively safe technique, it can still cause a number of complications, including minor and major complications. Through standard management and treatment, the outcome of most patients is very good. In the second section of this review, we describe a variety of minor and major tube-related complications, and the treatment and prevention of these complications. In addition, the preparation and post-insertion care are also very important for PEG, which can reduce the incidence of complications. In the last section of this review, we describe related issues about the preparation and post-insertion care of PEG. In conclusion, PEG tube placement is a widely accepted technique that can bring benefits to the right patients.

Set-membership Estimation for Event-triggered 2-D Systems Based on Zonotopes

Xudong Wang,Guoqi Wang,Liu Yang,Jitao Li 제어·로봇·시스템학회 2024 International Journal of Control, Automation, and Vol.22 No.3

This article discusses the interval estimation for 2-D systems in Roesser model with amplitude-boundedenvironmental disturbance and measurement noise. To save the limited capacity of communication network, anevent-triggered communication strategy is adopted to reduce the amount of packets transmitted through the network. Considering the amplitude-bounded uncertainties, an observer design criterion with peak-to-peak norm boundis deduced to suppress the influence of uncertainties on estimation error. A zonotope-based interval estimation approach is derived such that the actual state of 2-D Roesser system is enclosed within the estimated intervals on thebasis of the obtained observer. Finally, a numerical example is presented to verify the effectiveness of the proposedalgorithm

Effect of ages and season temperatures on bi-surface shear behavior of HESUHPC-NSC composite

Yang Zhang,Yanping Zhu,Pengfei Ma,Shuilong He,Xudong Shao Techno-Press 2023 Advances in concrete construction Vol.15 No.6

Ultra-high-performance concrete (UHPC) has become an attractive cast-in-place repairing material for existing engineering structures. The present study aims to investigate age-dependent high-early-strength UHPC (HESUHPC) material properties (i.e., compressive strength, elastic modulus, flexural strength, and tensile strength) as well as interfacial shear properties of HESUHPC-normal strength concrete (NSC) composites cured at different season temperatures (i.e., summer, autumn, and winter). The typical temperatures were kept for at least seven days in different seasons from weather forecasting to guarantee an approximately consistent curing and testing condition (i.e., temperature and relative humidity) for specimens at different ages. The HESUHPC material properties are tested through standardized testing methods, and the interfacial bond performance is tested through a bi-surface shear testing method. The test results quantify the positive development of HESUHPC material properties at the early age, and the increasing amplitude decreases from summer to winter. Three-day mechanical properties in winter (with the lowest curing temperature) still gain more than 60% of the 28-day mechanical properties, and the impact of season temperatures becomes small at the later age. The HESUHPC shrinkage mainly occurs at the early age, and the final shrinkage value is not significant. The HESUHPC-NSC interface exhibits sound shear performance, the interface in most specimens does not fail, and most interfacial shear strengths are higher than the NSC-NSC composite. The HESUHPC-NSC composites at the shear failure do not exhibit a large relative slip and present a significant brittleness at the failure. The typical failures are characterized by thin-layer NSC debonding near the interface, and NSC pure shear failure. Two load-slip development patterns, and two types of main crack location are identified for the HESUHPC-NSC composites tested in different ages and seasons. In addition, shear capacity of the HESUHPC-NSC composite develops rapidly at the early age, and the increasing amplitude decreases as the season temperature decreases. This study will promote the HESUHPC application in practical engineering as a cast-in-place repairing material subjected to different natural environments.

Does a High Circulating Tumor Cell Count in Portal Vein Predict the Involvement of Portal System in Pancreatic Cancer Patients?

ZHAO Xudong,DONG Xiu,MA Yongsu,GAO Hongqiao,TIAN Xiaodong,ZHAO Xiaohang,YANG Yinmo 대한외과학회 2018 대한외과학회 학술대회 초록집 Vol.2018 No.11

Improving the charge transfer performance of Si nanomaterial through C surface modification: A first-principles study

Yingying Yang,Xiaowan Xue,Yuan Qin,Hao Huang,Xudong Wang,Man Yao 한국물리학회 2019 Current Applied Physics Vol.19 No.7

Models of oxidized Si (111) surface under different C coverage were established to study the charge transfer ability of Si nanomaterial from strategy of C surface modification using first-principles calculation. The calculated formation energies show that structures of C surface-modified oxidized Si (111) surface are stable. The electronic properties present that the interaction between C and Si atoms is mainly contributed by the hybridization of C-2p and Si-3p states. And the interaction between C and Si atoms increases firstly and then decreases with the increasing C coverage rate. The transfer charge between C and Si reaches a maximum when C coverage rate is 0.5. We speculate that the conductivity of experimentally prepared Si nanomaterial does not monotonously enhance with the increasing C concentration, which would reach a maximum at a certain C concentration, and then decreases.

Dynamic Mechanical Performance of Self-compacting Concrete Containing Crumb Rubber under High Strain Rates

Guo Yang,Xudong Chen,Shengshan Guo,Weihong Xuan 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.8

The parameters of dynamic mechanical performance at high strain rates are of significant importance in the structural designs and numerical simulations. The aim of this paper is to study the strain rate sensitivity of self-compacting rubberized concrete (SCRC) in the dynamic compressive, splitting tensile and bending tests by using the split Hopkinson pressure bar (SHPB) technique. The failure modes, stress-strain curves and dynamic strength changes of SCRC under various loading conditions were also observed. The specific energy absorption, dynamic tensile-compressive strength ratios, and dynamic constitutive model of SCRC with different rubber content were also analyzed. The results indicate that SCRC can exhibit stronger strain rate sensitivity compared to SCC when strain rate is enough high, while the strain rate sensitivity of SCRC is lower than that of SCC at when strain rate is less than a critical value. To understand the strain rate sensitivity of SCRC, dynamic constitutive model (ZWT model) based on nonlinear viscoelastic theory was proposed. For impact toughness, although the specific energy absorption decreases with increasing rubber content, the ratios of tensile strength to compressive strength of SCRC have an increasing tendency when rubber content increases.

The microwave magnetism of epitaxy LiFe5O8 thin film modulated by thickness

Jiao Yang,Jianfei Lei,Kai Du,Xudong Zheng,Xiujuan Jin 한국물리학회 2020 Current Applied Physics Vol.20 No.4

Spinel lithium ferrite LiFe5O8 (LFO) has attracted robust research interests due to their potential applications in isolators, circulators, and phase shifters. In this work, a series of LFO thin film with various thickness were fabricated on SrTiO3 (STO) single-crystalline substrates by pulsed laser deposition technology. We systematically investigated the influences of the thickness of LFO thin film on the crystal structure and magnetic properties. The in-plane lattice parameter a and in-plane lattice parameter c were modulated by controlling the thickness of LFO thin film, which was confirmed using reciprocal space mappings (RSMs) technology. Furthermore, the microwave magnetism of LFO thin film with various thickness were studied systematically by ferromagnetic resonance (FMR) measurement. Moreover, with increasing the thickness of LFO thin film from 50 to 180 nm, the difference of the ferromagnetic resonance field between easy- and hard-magnetization axis can be enhanced and reach to 330 Oe. These results illustrate that dynamic magnetic properties can be controlled by tuning the thickness of LFO thin film. Our work provides an effective method to tailor the lattice parameter and modify the magnetic properties of the LFO thin film and contributes to further design high-frequency functional device.

Static Experiment on Mechanical Behavior of Innovative Flat Steel Plate-Concrete Composite Slabs

Yong Yang,Ru-yue Liu,Xudong Huo,Xianwei Zhou,Charles W. Roeder 한국강구조학회 2018 International Journal of Steel Structures Vol.18 No.2

A new type of composite slab is introduced in this paper, which is composed of normal fl at steel plates and concrete slabs, connected and interacted by perfobond shear connectors (PBL shear connectors). Experiments on six specimens of this type of composite slab, loaded at two symmetric two-points, were described in this paper to get mechanical behaviors under bending moments. During the experiments, the crack patterns, failure modes, failure mechanism and ultimate bending capacity of specimens with composite slab were investigated, and the strains of concrete and fl at steel plates were also measured and recorded in order to obtain the moment action. From the experimental results, it was found that composite interaction between the steel plate and the concrete fully developed, and such composite slab was verifi ed to have good mechanical performance with high bending capacity, substantial fl exural rigidity and good ductility. Plane section assumption was also verifi ed and moreover, a design approach including calculation methods of bending capacity and fl exural rigidity was established and proposed based on the experimental results, and the calculation methods were also verifi ed and revised on the basis of comparisons of the calculated results and experimental results. Results from this paper provide references for the application of this new type composite slab.