High-sensitivity phase imaging eddy current magneto-optical system for carbon fiber reinforced polymers detection

This paper proposed a high-sensitivity phase imaging eddy current magneto-optical (PI-ECMO) system for carbon fiber reinforced polymer (CFRP) defect detection. In contrast to other eddy current-based detection systems, the proposed system employs a fixed position excitation coil while enabling the detection point to move within the detection region. This configuration effectively mitigates the interference caused by the lift-off effect, which is commonly observed in systems with moving excitation coils. Correspondingly, the relationship between the defect characteristics (orientation and position) and the surface vertical magnetic field distribution (amplitude and phase) is studied in detail by theoretical analysis and numerical simulations. Experiments conducted on woven CFRP plates demonstrate that the designed PI-ECMO system is capable of effectively detecting both surface and internal cracks, as well as impact defects. The excitation current is significantly reduced compared with traditional eddy current magneto-optical (ECMO) systems.

固溶加热速率与Al−Mg−Si−Cu合金力学性能、显微组织及织构的关系

通过拉伸试验、扫描电镜、X射线衍射仪和EBSD技术研究固溶加热速率与Al-Mg-Si-Cu合金力学性能、显微组织及织构的关系。实验结果表明,固溶加热速率与力学性能、显微组织及织构的关系是非单调的。随着加热速率的增加,强度变化取决于拉伸方向;加工硬化指数n先减小,后增加;塑性应变比r值先增加,后减小,最后又增加。加热速率对合金最终显微组织和织构有一定影响。随着加热速率的增加,显微组织由拉长晶粒组织转变为等轴晶粒组织,平均晶粒尺寸呈先减小、然后增加、最后再减小的趋势。随着加热速率的增加,尽管织构组分如CubeND{001}<310>和P{011}<122>基本无变化,但织构密度和体积分数呈现先减小、后增加、最后减小的趋势。加热速率对显微组织和织构演变的影响较小。提高加热速率并不总是有利于形成细小的等轴晶粒组织、弱织构以及较大的平均r值,这些与合金的再结晶行为有关。

Progress in clinical trials of cell transplantation for the treatment of spinal cord injury:how many questions remain unanswered?

Spinal cord injury can lead to severe motor,sensory and autonomic nervous dysfunctions.However,there is currently no effective treatment for spinal cord injury.Neural stem cells and progenitor cells,bone marrow mesenchymal stem cells,olfactory ensheathing cells,umbilical cord blood stem cells,adipose stem cells,hematopoietic stem cells,oligodendrocyte precursor cells,macrophages and Schwann cells have been studied as potential treatments for spinal cord injury.These treatments were mainly performed in animals.However,subtle changes in sensory function,nerve root movement and pain cannot be fully investigated with animal studies.Although these cell types have shown excellent safety and effectiveness in various animal models,sufficient evidence of efficacy for clinical translation is still lacking.Cell transplantation should be combined with tissue engineering scaffolds,local drug delivery systems,postoperative adjuvant therapy and physical rehabilitation training as part of a comprehensive treatment plan to provide the possibility for patients with SCI to return to normal life.This review summarizes and analyzes the clinical trials of cell transplantation therapy in spinal cord injury,with the aim of providing a rational foundation for the development of clinical treatments for spinal cord injury.

Application of video-assisted thoracic surgery in the standard operation for thoracic tumors

Objective: To evaluate the short-term outcomes of video-assisted thoracic surgery (VATS) for thoracic tumors. Methods: The data of 1,790 consecutive patients were retrospectively reviewed. These patients underwent VATS pulmonary resections, VATS esophagectomies, and VATS resections of mediastinal tumors or biopsies at the Cancer Institute & Hospital, Chinese Academy of Medical Sciences between January 2009 and January 2012. Results: There were 33 patients converted to open thoracotomy (OT, 1.84%). The overall morbidity and mortality rate was 2.79% (50/1790) and 0.28% (5/1790), respectively. The overall hospitalization and chest tube duration were shorter in the VATS lobectomy group (n=949) than in the open thoracotomy (OT) lobectomy group (n=753). There were no significant differences in morbidity rate, mortality rate and operation time between the two groups. In the esophageal cancer patients, no significant difference was found in the number of nodal dissection, chest tube duration, morbidity rate, mortality rate, and hospital length of stay between the VATS esophagectomy group (n=81) and open esophagectomy group (n=81). However, the operation time was longer in the VATS esophagectomy group. In the thymoma patients, there was no significant difference in the chest tube duration, morbidity rate, mortality rate, and hospital length of stay between the VATS thymectomy group (n=41) and open thymectomy group (n=41). However, the operation time was longer in the VATS group. The median tumor size in the VATS thymectomy group was comparable with that in the OT group. Conclusions: In early-stage (I/II) non-small cell lung cancer patients who underwent lobectomies, VATS is comparable with the OT approach with similar short-term outcomes. In patients with resectable esophageal cancer, VATS esophagectomy is comparable with OT esophagectomy with similar morbidity and mortality. VATS thymectomy for Masaoka stage I and II thymoma is feasible and safe, and tumor size is not contraindicated. Longer follow-ups are needed to determine the oncologic equivalency of VATS lobectomy, esophagectomy, and thymectomy for thymoma vs. OT.

Meta-analysis of the success rate of heartbeat recovery in patients with prehospital cardiac arrest in the past 40 years in China

Background:Systematic evaluation of the successful heartbeat recovery rate(HRR)in patients during the platinum ten minutes after cardiac arrest.Methods:The databases of CNKI(January 1979–March 2019),Chongqing VIP(January 1989–March 2019),Wanfang(January 1990–March 2019)and Web of Science(January 1900-May 2020)were searched.To collect the clinical data of patients with cardiac arrest before hospitalization and analyze the cardiopulmonary resuscitation(CPR)at different times.Literature selection and data extraction were carried out by two researchers independently,and the meta package of R software(version 3.61)was used for analysis.Results:A total of 116 papers met the inclusion criteria,including 37,181 patients.Of these patients,3367 had their heartbeats successfully restored.The results showed a high degree of heterogeneity(χ2=6999.21,P<0.01,I2=97.6%).The meta-analysis was conducted using a random-effects model.The combined effect size was 0.199(0.157–0.250).(1)According to the five CPR groups(International Cardiopulmonary Resuscitation Guide 2000,2005,2010,2015 and other versions),the HRR of other versions[0.264(0.176–0.375)]was higher than the International Cardiopulmonary Resuscitation 2005 edition[0.121(0.092–0.158)].(2)The rescue time was divided into the 0 to≤5 min group,the 5 to≤10 min group,the 10 to≤15 min group,and the>15 min group.The HRR were 0.417(0.341–0.496),0.143(0.104–0.193),0.049(0.034–0.069),and 0.022(0.009–0.051),respectively.The HRR was higher in the 0 to≤5 min group than in the 5 to≤10 min group,the 10 to≤15 min group and the>15 min group.There was no difference between the 10 to≤15 min group and the>15 min group.(3)When the groups were stratified with the cutoff of 10 min,the≤10 min group HRR[0.250(0.202–0.306)]was higher than the>10 min group rate[0.041(0.029–0.057)].(4)The HRR of the telephone guidance group was[0.273(0.227–0.325)]lower than that of the 0 to≤5 min group[0.429(0.347–0.516)]but higher than that of the 5 to≤10 min group,the 10 to≤15 min group,and the>15 min group.(5)The HRR of the witness group[0.325(0.216–0.458)]was not different from that of the 0 to≤5 min group,but it was higher than those of the 5 to≤10 min group,the 10 to≤15 min group and the>15 min group.(6)There was no significant difference HRR between the witnessed group,the telephone guidance group and the≤10 min group.Conclusions:(1)The HRR is time-sensitive,and early rescue can improve it.(2)CPR performed within the platinum ten minutes must be executed by the public,and other forces are auxiliary.(3)The concept of peri-cardiac arrest period(PCAP)should be established and improved to guide CPR.

Dynamic Fracture Behaviors of Selected Aluminum Alloys Under Three-point Bending

The dynamic fracture behaviors of the extruded 2024-T4 and 7075-T6 aluminum alloys are investigated by using an instrumented drop tower machine.The specimens are made from a 25 mm diameter extruded circular rod.The dynamic three-point bending tests of each alloy are carried out at different impact velocities.The initiation fracture toughness and average propagation fracture toughness of 2024-T4 and 7075-T6 are determined at different loading rates.The results show that both the initiation toughness and the propagation toughness increase with the loading rate.Further,the difference between the fracture toughness behaviors of 2024-T4 and 7075-T6 is found to be dependent on the variation of fracture mechanism.The comprehensive fractographic investigations of the fracture surfaces clearly demonstrate that the fracture mode of 2024-T4 is predominantly transgranular fracture with high density small-sized dimples,and the fracture mode of 7075-T6 is mainly intergranular fracture with many intermetallic particles in the bottom of voids located in the fracture surface.

The potential application of the traditional Chinese herb Exocarpium Citri grandis in the prevention and treatment of COVID-19

Huajuhong(Exocarpium Citri grandis,ECG)is a traditional Chinese herbal medicine and has been used for the treatment of respiratory diseases for hundreds of years.Recently,ECG has been listed in a traditional Chinese medicine formula in the Guidelines for the Diagnosis and Treatment of Coronavirus Disease 2019(sixth edition)in China.To date,the effect and mechanism of ECG against respiratory diseases have not been systematically reviewed.In this paper,the researchers summarized the effects of ECG and its pharmacologically active compound naringin in functioning as an antitussive and expectorant,improving lung function,alleviating acute lung injury,attenuating pulmonary fibrosis,and enhancing antiviral immune response,so as to provide a reference for its clinical application in the prevention and treatment of multiple respiratory diseases,including coronavirus disease 2019.

Linking anisotropy with Fe_3C distribution in AISI 1045 steel

The anisotropy of the microstructure, thermal expansion behavior, corrosion resistance and magnetic properties of AISI 1045 steel was investigated. The distribution of Fe3C lameUae in the investigation plane parallel to the radial directions of molds was observed to differ from that in the investigation plane perpendicular to the radial directions by transmission electron microscopy. The lattice constants a0 of α-Fe deduced from the XRD patterns of samples prepared using a sand （S）-mold and cut parallel to the radial direction of the mold （S//） and using a metal （M）-mold and cut parallel to the radial direction （M//）, the corrosion resistance measured using an electrochemical work- station, and the magnetic permeability obtained by vibrating sample magnetometry also indicated the existence of anisotropy in the tested samples. The anisotropic change of corrosion potential （Eeorr）, pitting potential （Epit） and magnetic permeability （μ） of the samples was observed to depend on the orientation factorF200 of α-Fe in the measured samples, which is controlled by the distribution of Fe3C lamellae in the eutectoid structure.

Reduced graphene oxide as saturable absorbers for erbium-doped passively mode-locked fiber laser

We demonstrate a nanosecond mode-locked erbium-doped fiber laser （EDFL） based on a reduced graphene oxide （RGO） saturable absorber （SA）. The RGO SA is prepared by depositing the graphene oxide （GO） on fluorine mica through thermal reduction of GO. A scanning electron microscope （SEM）, Raman spectrometer, and x-ray photoelectron spec- troscopy （XPS） are adopted to analyze the RGO characteristics. The results show that the reduction degree of graphene oxide is very high. By embedding the RGO SA into the EDFL cavity, a stable mode-locked fiber laser is achieved with a central wavelength of 1567.29 nm and repetition rate of 12.66 MHz. The maximum output power and the minimum pulse duration are measured to be 18.22 mW and 1.38 ns respectively. As far as we know, the maximum output power of 18.22 mW is higher than those of other nanosecond mode-locked oscillators reported. Such a nanosecond pulse duration and megahertz repetition rate make this mode-locked erbium-doped fiber laser a suitable seed oscillator for high-power applications and chirped pulse amplifications.

Using Reduced Graphene Oxide to Generate Q-Switched Pulses in Er-Doped Fiber Laser

Using the reduced graphene oxide（rGO） as a saturable absorber（SA） in an Er-doped fiber（EDF） laser cavity,we obtain the Q-switching operation. The rGO SA is prepared by depositing the GO on fluorine mica（FM） using the thermal reduction method. The modulation depth of rGO/FM is measured to be 3.2%. By incorporating the rGO/FM film into the EDF laser cavity, we obtain stable Q-switched pulses. The shortest pulse duration is3.53 μs, and the maximum single pulse energy is 48.19 nJ. The long-term stability of working is well exhibited.The experimental results show that the rGO possesses potential photonics applications.

Structure-Spin-Transport Anomaly in Quasi-One-Dimensional Ba9Fe3Te15 under High Pressure

Recently,a series of novel compounds Ba3MX5(M=Fe,Ti,V;X=Se,Te)with hexagonal crystal structures composed of quasi-1-dimensional(1D)magnetic chains has been synthesized by our research team using high-pressure and high-temperature methods.The initial hexagonal phases persist to the maximum achievable pressure,while spin configurations and magnetic interactions may change dramatically as a result of considerable reductions in interchain separations upon pressurization.These compounds therefore offer unique possibilities for studying the evolution of intrinsic electronic structures in quasi-1D magnetic systems.Here we present a systematic investigation of Ba9Fe3Te15,in which the interchain separations between trimerized 1D chains(~10.2Å)can be effectively modulated by external high pressure.The crystal structure especially along the 1D chains exhibits an abnormal expansion at^GPa,which accompanies trimerization entangled anomalous mixed-high-low spin transition.An insulator-metal transition has been observed under high pressure as a result of charge-transfer gap closing.Pressure-induced superconductivity emerges at 26 GPa,where the charge-transfer gap fully closes,3D electronic configuration forms and local spin fully collapses.

城市公交-地铁加权复合网络构建及鲁棒性分析

基于复杂网络理论,本文将地铁、公交实际运营特性考虑其中,构建了加权复合网络,提出“出行成功率”与“绕行系数”两个鲁棒性评价新指标,以及更贴近于实际的2种新型攻击方式A与B。通过仿真实验,统计在蓄意攻击、随机攻击2类攻击策略的3种攻击模型下,加权复合网络评价指标(网络效率、最大连通子图率、绕行系数以及出行成功率)的变化情况,分析复合加权网络分别在蓄意攻击与随机攻击下,对上述3种攻击模型的鲁棒特性。结果表明:受到蓄意攻击时,绕行可达方面,复合网络对新型攻击方式A与B的鲁棒性能高于传统攻击方式;出行成功率方面,复合网络对新型攻击方式A的鲁棒性高于对传统攻击方式与新型方式B的鲁棒性。随机攻击下,绕行系数方面,复合网络对3种攻击模式呈现出的鲁棒性交替变化;出行成功率方面,对3者的鲁棒性为:新型攻击方式A>新型攻击方式B>传统攻击方式。

Annealing effects on the optical and electrochemical properties of tantalum pentoxide films

Tantalum pentoxide(Ta_(2)O_(5)) has attracted intensive attention due to their excellent physicochemical properties.Ta_(2)O_(5) films were synthesized via electron beam evaporation(EBE)and subsequently annealed at different temperatures ranging from 300 to 900℃.X-ray diffraction(XRD)results show that amorphous Ta_(2)O_(5) thin films form from 300 to 700℃ and then a phase transition to polycrystalline β-Ta_(2)O_(5) films occurs since 900℃.The surface morphology of the Ta_(2)O_(5) films is uniform and smooth.The resulted Ta_(2)O_(5)films exhibit excellent transmittance properties for wavelengths ranging from 300 to 1100 nm.The bandgap of the Ta_(2)O_(5) films is broadened from 4.32 to 4.46 eV by annealing.The 900℃ polycrystalline film electrode has improved electrochemical stability,compared to the other amorphous counterparts.