基于GPRS网络的金属氧化物避雷器在线监测系统设计

为了克服金属氧化物避雷器在线监测器有线传输方式存在的弊端,提出一种基于GPRS远程监测避雷器状态的新方法。利用该方法设计的监测系统主要包括现场采集部分、GPRS通信部分和远程监测中心系统管理部分。现场采集部分以TMS320F2812微处理器为核心处理器,对避雷器的阻性电流进行实时检测。现场采集结果通过GPRS发送到监测中心数据库中形成数据报表,在监测中心可以通过远程实时对避雷器状态进行监测和对历史数据进行查询分析,达到保证电力系统稳定运行的目的。

基于GPRS的接地电阻自动检测系统设计

根据短距法测量接地电阻的原理,采用单片机设计一个具有GPRS功能的接地电阻自动检测系统,以解决接地电阻自动检测及其测量数据的远距离传输问题。系统下位机主要由DDS电流源产生模块、A/D转换模块、GPRS模块、人机交互模块等构成。通过异频法选取检测信号频率,消除了地网工频干扰。上位机采用Delphi设计了上位机数据管理系统。系统具有接地电阻的远程自动测量和控制功能,并利用季节系数对接地电阻进行修正,避免了人工测量所带来的误差。

基于GPRS的微电网中蓄电池远程监测系统设计

为了满足微电网中储能蓄电池健康状态监测需求,该文基于GPRS技术设计一种远程监测系统。设计主要以检测蓄电池内阻为主,该系统以处理器dsPIC30F6012为核心,控制DDS芯片AD9833产生正弦波信号,经过恒流源驱动作用到蓄电池回路,再通过差分放大、带通滤波、有效值转换等电路采集蓄电池和参考电阻两端得到的交流电压信号,进而计算出蓄电池内阻。处理器获得相关数据后与设定限值比较,当数据异常时通过GPRS通信远程上传至上位数据中心服务器,提醒工作人员注意并进行相应处理,以提高微电网中储能装置运行的稳定性、可靠性。该系统设计简单、易于实现,具有一定的工程应用参考价值。

基于CAN和GPRS技术汽车防盗抢智能系统研究

针对目前市场常用汽车防盗系统存在功能单一、可靠性低及非智能的不足,提出一种既防盗又防抢、实现远程监控的网络智能型汽车防盗抢系统——基于CAN和GPRS技术汽车防盗抢智能系统。当车辆被非法移动和破坏时,系统利用CAN技术及GPRS网络技术将被盗抢信息、图片和GPS定位信息发送给车主,车主即可对车辆实施远程控制并报警,挽回经济损失。文章主要从系统的总体结构及工作原理、系统硬件的研究及系统软件的设计三部分进行介绍。

Prediction of future capacity and internal resistance of Li-ion cells from one cycle of input data

There is a large demand for models able to predict the future capacity retention and internal resistance(IR)of Lithium-ion battery cells with as little testing as possible.We provide a data-centric model accurately predicting a cell’s entire capacity and IR trajectory from one single cycle of input data.This represents a significant reduction in the amount of input data needed over previous works.Our approach characterises the capacity and IR curve through a small number of key points,which,once predicted and interpolated,describe the full curve.With this approach the remaining useful life is predicted with an 8.6%mean absolute percentage error when the input-cycle is within the first 100 cycles.

The Electric Mechanism of Surface Pretreatments for Dye-Sensitized Solar Cells Based on Internal Equivalent Resistance Analysis

Based on the optimization of dye-sensitized solar cell (DSC) photoelectrodes pretreated with different methods such as electrodeposition,spin-coating and TiCl_(4) pretreatment,theoretical calculations are carried out to interpret the internal electric mechanism.The numerical values,including the series resistance R_(s) and the shunt resistance R_(sh) corresponding to the equivalent circuit model,are well evaluated and confirm that the DSC has good performance with a high R_(sh) and a low R_(s) due to good electrical contact and a low charge recombination after the different modifications.The Ⅰ-Ⅴ curves are fifted in the case without series resistance,and account for the role of R_(s) in the output characteristics.It is found that when R_(s) tends to the infinitesimal,the short-circuit current Isc,the open-circuit voltage V_(oc) and the fill factor can be improved by almost 0.8-1.4,2.9 and 2.1-6.8%,respectively.

Resistance Factor of Caisson-Tip with Internal Fillet for Suction Caissons Penetrating into Clay

This paper presents failure mechanisms of the soil at the caisson-tip with fillet during suction-assisted penetration of suction caissons in undrained clay.Theoretical solutions of resistance factor N_c of the caisson-tip are obtained in terms of the caisson-tip geometry ratio of the flat section of the caisson-tip to the caisson wall thickness m/t and adhesion factorsα_i along inside of caisson wall andα_b at the base of the caisson-tip.It is indicated that the factor N_c increases with the increase of m/t,α_i and a_b.The resistance factors N_c for the rough base(α_b=1)are larger by 0.57than that for the smooth base(α_b=0).Besides,the factors N_c of caisson-tip with flat base(m=t)are larger by 1.14 than that with full internal fillet(m=0).The required suction to penetrate suction caissons with various fillets is obtained in terms of the force equilibrium in vertical direction.The finite element limit analysis and centrifuge model test results are used to verify the rationality of the presented failure mechanisms and theoretical predictions.

Effect of Black Plate on Corrosion Resistance of T5 Tinplate

The effect of black plate on corrosion resistance of T5 tinplate was studied by glow discharge spectrograph, X-ray diffractometer （XRD）, stress tester, roughness tester and metallographic microscope. The result shows that black plate influences corrosion resistance of T5 tinplate intensely. It also indicates that the increase of content of manganese, phosphorus, silicon and aluminum in black plate would reduce the corrosion resistance of T5 tinplate and the increase of degree of crystal orientation on （200） crystal face, ｜X-Y｜ value （internal stress difference within two orientation）, roughness and exposure degree of iron grain after the same acid wash of black plate would enhance the corrosion resistance of T5 tinplate and the grain number of black plate has small effect on corrosion resistance of T5 tinplate.

Low Cycle Fatigue and Strengthening Mechanism of Cold Extruded Large Diameter Internal Thread of Q460 Steel

large diameter internal thread of high-strength steel（LDITHSS） manufactured by traditional methods always has the problems of low accuracy and short life. Compared with traditional methods, the cold extrusion process is an effective means to realize higher accuracy and longer life. The low-cycle fatigue properties of LDITHSS are obtained by experiments, and the initiation and propagation of fatigue cracks are observed by scanning electron microscope（SEM）. Based on the mechanical properties, surface microstructure and residual stress, the strengthening mechanism of cold extruded large diameter internal thread（LDIT） is discussed. The results show that new grains or sub-grains can be formed on the surface of LDIT due to grain segmentation and grain refinement during cold extrusion. The fibrous structures appear as elongated and streamlined along the normal direction of the tooth surface which leads to residual compressive stress on the extruded surface. The maximum tension stress of LDIT after cold extrusion is found to be 192.55 k N. Under low stress cycling, the yield stress on thread increases, the propagation rate of crack reduces, the fatigue life is thus improved significantly with decreasing surface grain diameter and the average fatigue life increases to 45.539×10~3 cycle when the maximum applied load decreases to 120 k N. The low cycle fatigue and strengthening mechanism of cold extruded LDIT revealed by this research has significant importance to promote application of internal thread by cold extrusion processing.

Data-driven short circuit resistance estimation in battery safety issues

Developing precise and fast methods for short circuit detection is crucial for preventing or mitigating the risk of safety issues of lithium-ion batteries(LIBs).In this paper,we developed a Convolutional Neural Networks(CNN)based model that can quickly and precisely predict the short circuit resistance of LIB cells during various working conditions.Cycling tests of cells with an external short circuit(ESC)are produced to obtain the database and generate the training/testing samples.The samples are sequences of voltage,current,charging capacity,charging energy,total charging capacity,total charging energy with a length of 120 s and frequency of 1 Hz,and their corresponding short circuit resistances.A big database with~6×10^(5)samples are generated,covering various short circuit resistances(47~470Ω),current loading modes(Constant current-constant voltage(CC-CV)and drive cycle),and electrochemical states(cycle numbers from 1 to 300).Results show that the average relative absolute error of five random sample splits is 6.75%±2.8%.Further parametric analysis indicates the accuracy estimation benefits from the appropriate model setups:the optimized input sequence length(~120 s),feature selection(at least one total capacity-related variable),and rational model design,using multiple layers with different kernel sizes.This work highlights the capabilities of machine learning algorithms and data-driven methodologies in real-time safety risk prediction for batteries.

Resistance to FLT3 inhibitors in acute myeloid leukemia: Molecular mechanisms and resensitizing strategies

FMS-like tyrosine kinase 3(FLT3) is classified as a type Ⅲ receptor tyrosine kinase, which exerts a key role in regulation of normal hematopoiesis. FLT3 mutation is the most common genetic mutation in acute myeloid leukemia(AML) and represents an attractive therapeutic target. Targeted therapy with FLT3 inhibitors in AML shows modest promising results in current ongoing clinical trials suggesting the complexity of FLT3 targeting in therapeutics. Importantly, resistance to FLT3 inhibitors may explain the lack of overwhelming response and could obstruct the successful treatment for AML. Here, we summarize the molecular mechanisms of primary resistance and acquired resistance to FLT3 inhibitors and discuss the strategies to circumvent the emergency of drug resistance and to develop novel treatment intervention.

Metformin effect on internal carotid artery blood flow assessed by area under the curve of carotid artery Doppler in women with polycystic ovarian syndrome

BACKGROUND Insulin resistance(IR)was reported in most polycystic ovarian syndrome(PCOS)cases.Metformin,a biguanide drug,successfully reduced IR.Homeostatic Model Assessment for IR(HOMA-IR)and Doppler parameters assessed metformin's effectiveness.AIM To verify whether the area under the curve of the internal carotid artery(AUC-ICA)Doppler wave can be a useful marker for assessing IR among PCOS cases who presented with menstrual irregularity and were treated with metformin over 6 mo.METHODS An observational,cross-sectional study recruited 54 eligible PCOS women;the anthropometrics were as follows:age,body mass index(BMI),menstrual cycle days,biochemical serum cholesterol,low and high-density lipoprotein,sex hormone-binding globulin,fasting blood glucose,and HOMA-IR,hormonal testosterone,luteinizing hormone over follicle-stimulating hormone ratio,and ultrasonic pulsatility index(PI)and resistance index(RI),carotid artery intima-media thickness(CIMT)and(AUC-ICA)parameters were initially recorded and repeated 3 mo and 6 mo later with metformin tab 500 mg;three times/day for 6 mo.In addition,AUC-ICA was assessed by taking repeated systolic and diastolic wave height measurements.RESULTS Metformin caused a progressive reduction in BMI,menstrual cycle days,biochemical hormonal,and Doppler parameters(CIMT,PI,RI,and AUC-ICA).AUC-ICA correlated strongly to all PCOS parameters.AUC-ICA correlated inversely with treatment time(r=-0.98,P<0.001)and positively with HOMA-IR(r=0.98,P<0.0001).Via the best subset regression model,the AUC-ICA had the highest predictive value for HOMA-IR.CONCLUSION AUC-ICA preceded PI,RI,and CIMT with a strong,meaningful correlation to all PCOS parameters,making it a reliable marker for the assessment of IR,especially during metformin therapy.Further studies are recommended to promote the application in practice.

Exploration on Internal Inlaying Drip Irrigation Pipe and Standards

In the test, internal inlay drip irrigation pipes with different wal thicknesses or diameters （￠at 12 mm and 16 mm） were tested under varying tension forces and it was concluded that 90 N is the rational one. What’s more, the smal er drip-irrigation inner diameter, the thinner wal thickness, and the higher tension force, the lower acceptability, and the larger drip-irrigation inner diameter, the thicker wal thickness, and the lower tension force, the higher acceptability. The causes were analyzed in the research, including manufacturing technique leading to disqualifica-tion and different specifications with the same demands on techniques, and inadap-tation to tension force at 130 N.

Efficacy and Risk Factors Associated to Resistance to Single-Agent Chemotherapy in Low-Risk Gestational Trophoblastic Neoplasia

Objectives: This study aimed to assess efficacy of intramuscular methotrexate 8-day protocol in the treatment of low-risk gestational trophoblastic neoplasia and also identify prognostic factors associated with treatment failure, necessitating second line chemotherapy. Methods: This study was performed at Gynaecologic and Obstetric Clinic of Dakar Teaching Hospital, the reference Centre of Gestational Trophoblastic Disease in Senegal. At the beginning of 2011, patients were followed according to FIGO’s recommendations. From 2011 to 2014, we diagnosed 88 low-risk gestational trophoblastic neoplasia (GTN) patients (WHO score < 7). Low-risk patients started their treatment with methotrexate (MTX) based on the 8-day protocol consisting of 1 mg/kg MTX in combination with 0.1 mg/kg folinic acid (FA) every other day. Resistance to treatment was the main outcome. We studied the association of different prognostic factors included in the World Health Organisation (WHO) scoring system and resistance to the initial single agent chemotherapy. Results: Eighty-eight patients were diagnosed for GTN during the study period. Average age was 31 years. The antecedent pregnancy was molar in 98.1% of cases. Seventy-four patients underwent remission after single agent-chemotherapy. Resistance rate to single-agent chemotherapy was 15.9% (14 patients). Nine of them achieved remission after second line chemotherapy. WHO score was significantly associated with the risk of resistance to single-agent chemotherapy. Other variables included in the WHO as age, antecedent pregnancy, pre-treatment hCG, tumour size and FIGO stage were not significantly associated with resistance. We report five fatal cases. Conclusion: The 8-day protocol consisting of 1 mg/kg MTX in combination with 0.1 mg/kg folinic acid (FA) every other day is effective for women with LRGTN. The only significant prognostic factor for failure is pretreatment WHO score. We highly recommend the use of this protocol particularly in developing countries where methotrexate is available, affordable and relatively safe.

Developing an approach to assessing the political feasibility of global collective action and an international agreement on antimicrobial resistance

Background:Antimicrobial resistance(AMR)is a global issue.International trade,travel,agricultural practices,and environmental contamination all make it possible for resistant microbes to cross national borders.Global collective action is needed in the form of an international agreement or other mechanism that brings states together at the negotiation table and commits them to adopt or implement policies to limit the spread of resistant microorganisms.This article describes an approach to assessing whether political and stakeholder interests can align to commit to tackling AMR.Methods:Two dimensions affecting political feasibility were selected and compared across 82 countries:1)states’global influence and 2)self-interest in addressing AMR.World Bank GDP ranking was used as a proxy for global influence,while human antibiotic consumption(10-year percent change)was used as a proxy for self-interest in addressing AMR.We used these data to outline a typology of four country archetypes,and discuss how these archetypes can be used to understand whether a proposed agreement may have sufficient support to be politically feasible.Results:Four types of countries exist within our proposed typology:1)wealthy countries who have the expertise and financial resources to push for global collective action on AMR,2)wealthy countries who need to act on AMR,3)countries who require external assistance to act on AMR,and 4)neutral countries who may support action where applicable.Any international agreement will require substantial support from countries of the first type to lead global action,and from countries of the second type who have large increasing antimicrobial consumption levels.A large number of barriers exist that could derail efforts towards global collective action on AMR;issues of capacity,infrastructure,regulation,and stakeholder interests will need to be addressed in coordination with other actors to achieve an agreement on AMR.Conclusions:Achieving a global agreement on access,conservation,and innovation–the three pillars of AMR–will not be easy.However,smaller core groups of interested Initiator and Pivotal Countries could develop policy and resolve many issues.If highly influential countries take the lead,agreements could then be scaled up to achieve global action.

合肥新桥国际机场T2航站楼结构设计

新建合肥新桥国际机场T2航站楼采用下部为混凝土结构、顶部屋盖为大跨钢结构的结构形式,结构设计基于建筑特点和场地条件展开。介绍了基于场地表面起伏较大、需进行大面积回填条件下的桩基选型过程和桩基施工流程,详细阐述了基于建筑结构一体化理念的大跨屋盖结构体系及其支承结构的确定过程。根据航站楼的功能特点,通过比选确定主楼采用速度型减震装置的消能减震方案,提高结构的耗能能力并实现良好的抗震性能。通过抗连续倒塌分析和抗火分析确定钢屋盖及其支撑柱的防护方法,对钢管混凝土柱与下部钢筋混凝土柱等截面的连接节点进行了数值分析,最后对屋盖钢桁架的管-管相交节点确定原则进行了介绍。结果表明:该航站楼结构设计可靠,满足各项要求。

骨折内固定术后感染金黄色葡萄球菌患者的耐药监测及临床分析

目的 分析金黄色葡萄球菌在骨折内固定术后感染患者中的耐药情况。方法 回顾性分析四川省骨科医院2016年1月至2020年12月骨折内固定术后确诊为金黄色葡萄球菌感染的临床病例,共收集金黄色葡萄球菌467株。根据药物敏感性实验分为耐甲氧西林金黄色葡萄球菌(MRSA)组(145株)和甲氧西林敏感金黄色葡萄球菌(MSSA)组(322株),分析比较2组对常见抗菌药物的耐药情况。统计2016—2020年万古霉素对MRSA最低抑菌浓度(MIC)。结果 金黄色葡萄球菌对青霉素的耐药率达94.9%(443/467),对红霉素、克林霉素、苯唑西林、四环素耐药率较高,对左氧氟沙星、利福平、复方磺胺甲噁唑片、莫西沙星的耐药率较低[8.4%(39/467)、5.8%(27/467)、3.6%(17/467)、3.0%(14/467)],未发现对万古霉素、利奈唑胺、达托霉素耐药的菌株,万古霉素中介3株。MRSA组和MSSA组对克林霉素、苯唑西林、红霉素、左氧氟沙星、莫西沙星、青霉素、利福平、复方磺胺甲噁唑片、四环素的耐药率比较差异均有统计学意义(均P<0.05)。万古霉素对MRSA的MIC为2 mg/L的比例较高。结论 金黄色葡菌球菌引起的骨折内固定术后感染MRSA检出率较高,万古霉素MIC=2 mg/L的比例较高,降低了万古霉素治疗骨折内固定术后感染的达标率,且万古霉素骨组织渗透率不高,增加了临床治疗难度。因此万古霉素骨水泥植入,联合万古霉素静脉用药,或万古霉素静脉用药与利福平、喹诺酮类、磺胺类、利奈唑胺等联合用药可能是治疗骨折内固定术后感染的较好选择。

小样本条件下动力电池容量和内阻协同估计

锂离子电池的容量和内阻分别是表征电池系统能量和功率特性的重要参数,准确估计容量和内阻对于电动汽车电池管理系统有至关重要的作用.提出了一种数据驱动的电池容量和内阻估计方法.该方法首先从电池的恒流充电片段提取容量增量(incremental capacity,IC)特征,经过重采样方法构建特征向量.然后将IC特征输入弹性网络模型进行训练,从而实现容量和内阻估计.应用KIT数据集对所提方法进行验证.结果表明:该模型可以在相同特征输入下实现高精度的容量和内阻协同估计,且在小样本训练(仅使用2个电池作为训练集)时保持容量估计误差在2%以内,内阻的估计误差在3%以内.最后提出了基于容量和内阻双参量的“三段式”电池评价方法.

抗战时期西北国际通道初探

西北国际通道是抗战时期经中国西北地区运输外国援华物资、援华人员和中国易货物资的重要国际通道,西北国际通道的开辟与运行对于中国抗日战争胜利发挥了极为重要的历史作用。学界对西北国际通道研究十分关注,现有研究对其基本概念如名称、路线、里程认识并不一致。文章依据通道地理位置及运输状况将其定名为西北国际通道;通过梳理抗战时期报纸、期刊、书籍等资料,分析得出通道有三条线路,公路线起自今哈萨克斯坦萨雷奥泽克车站,终于兰州,航空线为阿拉木图至兰州,驿运线为印度列城至中国新疆叶城;以修建维护通道的新疆公路局、西北公路局等机构资料为依据,考订西北国际通道公路线里程为2934公里。

浦东国际机场T3航站区地下综合交通枢纽结构设计及关键问题研究

浦东国际机场四期T3航站区地下综合交通枢纽工程为濒海环境的超深超大地下工程,建筑面积约为64万m^(2)。多条地铁及捷运、排水渠、市政道路设施等穿越地下室,轨交、市政结构与航站楼地下建筑结构合建,结构复杂程度高。介绍了工程的主要结构特点、桩基础前期试验研究和选型设计、多种功能合建地下结构设计方法;阐述了超大型复建式地下结构抗震分析、地下综合枢纽结构抗震性能化设计、开敞式地下室对结构抗震设计影响、超长地下结构抗裂抗渗设计、地铁振动对结构舒适度的影响、地下通道合建转换结构抗爆分析等若干关键结构设计问题的研究和应对措施。