基于数据采集卡和组态软件的PLC控制系统仿真

以基于PLC的液气联调试验台为背景,针对PLC控制系统存在现场调试难度大、组织投入大量人力物力、风险大等问题,采用数据采集卡和组态软件开发用于PLC程序调试的仿真系统,其由PLC、接口板和PC机组成,PLC的I/O信号通过接口板与PC机中的数据采集卡相连,在PC机中,用组态软件模拟试验台测试工况,实现试验台控制程序的仿真调试。实践表明,该系统减少了现场调试工作量,提高了开发效率。     

New insight into the formation and oxygen barrier mechanism of carbonaceous oxide interlayer in a multicomponent carbide

Early transition metal carbides are considered to be superior candidate materials for oxidizing environments at temperatures exceeding 2000°C. Generally, the remarkable oxidation resistance is largely attributed to a carbonaceous oxide interlayer (eg, Hf–O–C, Zr–O–C, and Ta–O–C), located at the interface between the external oxide layer and internal carbide (eg, HfC, ZrC, and TaC), acting as the primary oxygen barrier. However, the oxygen barrier mechanism of the carbonaceous oxide interlayer remains unclear. Herein, through studying the oxidation behavior of a novel multicomponent carbide Hf_0.5Zr_0.3Ti_0.2C in oxidizing environments up to 2500°C, the oxygen barrier mechanism of the carbonaceous oxide was recently revealed. We found that the oxygen barrier resulted from the slow oxygen diffusion through the inner grains of Hf-Zr–Ti–O due to the presence of carbon formed at the grain boundaries because of the existence of compact external oxide layer, beneath which the Hf–Zr–Ti–O–C interlayer possesses much lower oxygen activity and temperature that allow carbon to exist stably. This as-formed carbon strongly retarded the fast diffusion of oxygen along the grain boundaries of oxides. Additionally, desirable synergisms of the designed multicomponent system, particularly, the outward short-circuit diffusion of Ti, lead to the self-healing of the external oxide layer, evidently enhancing integral protection performance against oxidizing environments.     

Strengthen flame retardancy of epoxy thermoset by montmorillonite particles adhering phosphorus-containing fragments

Phosphaphenanthrene derivative tri-(3-DOPO-2-hydroxypropan-1-yl)-1,3,5-triazine-2,4,6-trione (TGD) and organo-modified montmorillonite (OMMT) were jointly introduced into the diglycidyl ether of bisphenol A cured by 4,4-diamino-diphenylmethane (EP) to investigate their flame retardant behaviors. With only addition of 0.5%OMMT and 2.5%TGD, epoxy thermoset achieved a limiting oxygen index value of 33.7% and passed UL 94 V-0 rating test. Compared with the combustion behaviors of 3%OMMT/EP and 3%TGD/EP, an obvious synergistic flame retardant effect between OMMT and TGD can be concluded in OMMT/TGD/EP. Meanwhile, the FTIR spectra of gas-phase and condensed-phase products further proved this synergistic effect working in a physical way. On one hand, the co-existence of hydroxyl-containing TGD enabled montmorillonite (MMT) particles to filtrate and adhere more smoke fragments. On the other hand, the co-action of MMT help the polar phosphorus-containing fragments from TGD better strengthened char layer, enhancing the barrier and protective effect of residue. The synergistic flame retardant effect from OMMT/TGD system endowed themselves with higher flame retardant efficiency, and epoxy thermoset with better flame retardant performance. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 47500.     

Plate-like carbon-supported Fe_3C nanoparticles with superior electrochemical performance

Iron-based anodes for lithium-ion batteries(LIBs) with higher theoretical capacity,natural abundance and cheapness have received considerable attention,but they still suffer from the fast capacity fading.To address this issue,we report a facile synthesis of plate-like carbonsupported Fe3 C nanoparticles through chemical blowing/carbonization under calcination.The ultrafine Fe3 C nanoparticles are prone to be oxidized when exposing in air;thus,Fe3 C/C with mild oxidization and the fully oxidized product of Fe_2 O_3/C are successfully prepared by controlling the oxidization condition.When applied as an anode material in LIB,the Fe3 C/C electrode demonstrates excellent cycle stability(826 mAh·g~(-1) after 120 cycles under 500 mA·g~(-1)) and rate performance(410.6 mAh·g~(-1)under 2 A·g~(-1)),compared with the Fe_2 O_3/C counterpart.The enhanced electrochemical performance can be ascribed to the synergetic effect of the Fe3 C with mild oxidation and the unique hierarchical structure of plate-like carbon decorated with Fe_3 C catalyst.More importantly,this work may offer new approaches to synthesize other transition metal(e.g.,Co,Ni)-based anode material by replacing the precursor ingredient.     

秦皇岛市某仓库三种火灾蔓延等级下火灾特性的数值模拟研究

火灾是危及人民生活的最频繁灾难之一,科学防火成为未来消防安全的重要方向.火灾发生时会产生大量的热,并同时释放对人体有害的燃烧产物.文中以秦皇岛市某仓库为例,使用流体动力学软件Fluent对中等、快速和极快三种火灾蔓延等级下火灾特性开展数值模拟.分析火灾发生后,温度场的分布特性和燃烧产物(CO、CO2)的流动特性,及其影...     

Single-event effects induced by medium-energy protons in 28 nm system-on-chip

Single-event effects(SEEs) induced by medium-energy protons in a 28 nm system-on-chip(So C) were investigated at the China Institute of Atomic Energy. An on-chip memory block was irradiated with 90 MeV and70 MeV protons, respectively. Single-bit upset and multicell upset events were observed, and an uppermost number of nine upset cells were discovered in the 90 MeV proton irradiation test. The results indicate that the SEE sensitivities of the 28 nm SoC to the 90 MeV and 70 MeV protons were similar. Cosmic Ray Effects on Micro-Electronics Monte Carlo simulations were analyzed, and it demonstrates that protons can induce effects in a 28 nm SoC if their energies are greater than 1.4 MeV and that the lowest corresponding linear energy transfer was 0.142 MeV cm~2 mg~(-1). The similarities and discrepancies of the SEEs induced by the 90 MeV and 70 MeV protons were analyzed.     

Electrostatic-lenses position-sensitive TOF MCP detector for beam diagnostics and new scheme for mass measurements at HIAF

A foil–microchannel plate(MCP) detector,which uses electrostatic lenses and possesses both good position and timing resolutions, has been designed and simulated for beam diagnostics and mass measurements at the next-generation heavy-ion-beam facility HIAF in China. Characterized by low energy loss and good performances of timing and position measurements, it would be located at focal planes in fragment separator HFRS for position monitoring, beam turning, Bρ measurement, and trajectory reconstruction. Moreover, it will benefit the building-up of a magnetic-rigidity–energy-loss–time-offlight(Bρ-△E-TOF) method at HFRS for high-precision in-flight particle identification of radioactive isotope beams on an event-by-event basis. Most importantly, the detector can be utilized for in-ring TOF and position measurements,beam-line TOF measurements at two achromatic foci, and position measurements at a dispersive focus of HFRS, thus making it possible to use two complementary mass measurement methods [isochronous mass spectrometry at the storage ring SRing and magnetic-rigidity–time-of-flight(Bρ-TOF) at the beam-line HFRS] in one single experimental run.     

Photosensitizer Nanoparticles Boost Photodynamic Therapy for Pancreatic Cancer Treatment

Patients with pancreatic cancer(PCa)have a poor prognosis apart from the few suitable for surgery.Photodynamic therapy(PDT)is a minimally invasive treatment modality whose efficacy and safety in treating unresectable localized PCa have been corroborated in clinic.Yet,it suffers from certain limitations during clinical exploitation,including insufficient photosensitizers(PSs)delivery,tumor-oxygenation dependency,and treatment escape of aggressive tumors.To overcome these obstacles,an increasing number of researchers are currently on a quest to develop photosensitizer nanoparticles(NPs)by the use of a variety of nanocarrier systems to improve cellular uptake and biodistribution of photosensitizers.Encapsulation of PSs with NPs endows them significantly higher accumulation within PCa tumors due to the increased solubility and stability in blood circulation.A number of approaches have been explored to produce NPs co-delivering multi-agents affording PDT-based synergistic therapies for improved response rates and durability of response after treatment.This review provides an overview of available data regarding the design,methodology,and oncological outcome of the innovative NPs-based PDT of PCa.     

多头纺改造技术探讨

以Barmag的ACW 10头卷绕头改20头为例,介绍了多头纺改造的基本技术,以及纺同一品种丝的生产情况,并对改造前后纺同一品种丝的物理指标进行了比较,得出多头纺改造是目前生产差别化纤维、提高产品附加值比较理想的方法。