Arc Behaviours in Vacuum Interrupters with Axial Magnetic Field Electrodes

To improve the limiting current interruption capability and minimizing vacuum interrupter with axial magnetic field （AMF） electrodes, it is significant to investigate the vacuum arc behaviours between the contacts. AMF distributions of the slot type electrodes were studied by both numerical analysis and experiments. Furthermore, the behaviours of vacuum arcs for different parameters of the slot type AMF electrodes were investigated by using high-speed CCD camera. The influences of gap distance, contact diameter and phase shift time between AMF and arc current on the vacuum arc were investigated. The results provide a reference for research and development of vacuum interrupters with slot type or other types of AMF electrode.

Vacuum interrupter,high reliability component of distribution switches,circuit breakers and contactors

The use of vacuum interrupters(VIs)as the current interruption component for switches,circuit breakers,reclosers and contactors operating at distribution voltages has escalated since their introduction in the mid-1950’s.This electrical product has developed a dominating position for switching and protecting distribution circuits.VIs are even being introduced into switching products operating at transmission voltages.Among the reasons for the VI’s popularity are its compactness,its range of application,its low cost,its superb electrical and mechanical life and its ease of application.Its major advantage is its well-established reliability.In this paper we show how this reliability has been achieved by design,by mechanical life testing and by electrical performance testing.We introduce the“sealed for life”concept for the VI’s integrity.We discuss this in terms of what is meant by a practical leak rate for VIs with a life of over 30 years.We show that a simple high voltage withstand test is an easy and effective method for monitoring the long-term vacuum integrity.Finally we evaluate the need for routine inspection of this electrical product when it is used in adverse ambient environments.

Influence of Gap Distance on Vacuum Arc Characteristics of Cup Type AMF Electrode in Vacuum Interrupters

The greenhouse effect of SFe is a great concern today. The development of high voltage vacuum circuit breakers becomes more important. The vacuum circuit breaker has minimum pollution to the environment. The vacuum interrupter is the key part of a vacuum circuit breaker. The interrupting characteristics in vacuum and arc-controlling techniue are the main problems to be solved for a longer gap distance in developing high voltage vacuum interrupters. To understand the vacuum arc characteristics and provide effective technique to control vacuum arc in a long gap distance, the arc mode transition of a cup-type axial magnetic field electrode is observed by a high-speed charge coupled device （CGD） video camera under different gap distances while the arc voltage and arc current are recorded. The controlling ability of the axial magnetic field on vacuum arc obviously decreases when the gap distance is longer than 40 ram. The noise components and mean value of the arc voltage significantly increase. The effective method for controlling the vacuum arc characteristics is provided by long gap distances based on the test results. The test results can be used as a reference to develop high voltage and large capacity vacuum interrupters.

Investigation on X-Radiation for 126 kV Vacuum Interrupters

When subjected to high voltages between opened contacts, vacuum interrupters may emit X-rays. In order to ensure that these are of an acceptable level, vacuum interrupters should comply with the limits for X-ray emission and the test procedures to be carried out to verify this based on relevant standards and specifications. In this paper, a comprehensive experimental study has been performed for 126 kV vacuum interrupters used in a transmission system to understand the X-radiation level and its influence by three main parameters, namely applied power-frequency voltage, contact gap and power=frequency voltage conditioning. The radiation instrument is an FJ347 radiometer and the X-radiation dose was measured at the power-frequency test voltage. These tests demonstrated that the X-radiation emission level for a 126 kV vacuum interrupter did not exceed the following： 5 μSv per hour at a rated voltage of 126 kV and 150 μSv per hour at a power-frequency voltage of 230 kV at 1 m distance. The X-radiation dose increased with the applied power-frequency voltage increasing and decreased with the contact gap increasing. The X- radiation dose for 126 kV vacuum interrupters decreased by 57% after the conditioning procedure with a certain power-frequency voltage. During the conditioning procedure, the average value of the X-radiation dose was 4.49 mSv, which means if a professional conditions 180 interrupters per year, it will be safe at the 6.4 m distance.

The jointing stress analysis of one-shot seal-off high-voltage vacuum interrupters

The free shrinkage of ceramic or metal is restricted due to solidification of the solder. Hence the shrinkage stress arises and the jointing strength is reduced during the brazing of high-voltage vacuum interrupters （HVVIs）. The solder bound contour was gained by solved energy bound equation. The finite element model of weld beads was established with Surface Evolver software. Then the stress in two different cooling techniques （ natural cooling and force cooling） was calculated with ANSYS. Comparing the stress, a better cooling technique was selected for HVVIs. Its cooling time is shortened by 3 hours while the jointing stress doesn＇ t increase and the tensile strength of ceramic to metal seal is not decreased. The stress-rupture tests have validated the calculated results. More important, a method is found, by which the brazing technique could be improved in advance instead of blind experiments.

Influence of Interrupted Childhood Biographies on Health Development: Evaluation of the Scientific Literature on the Example of Being Taken into Care*

Background: An interrupted family history, as is the case after taking someone into care, can complicate collecting family anamnesis data. In addition, the interrupted family history itself could be considered part of a person’s risk profile. Aim and methods: Literature analysis was conducted to examine whether there are scientific studies on health development after placement in out-of-home-care in order to recognise any existing medical characteristics that may be relevant for internal medical care. Results: There are few scientific publications on the health development of people after being placed in out-of-home-care. Direct reactions to the stress of being taken into custody include nausea and fever. However, effects that go beyond the acute situation and last into adulthood have also been described, such as AD(H)D, asthma, diabetes, cancer, hypertension and cardiovascular diseases (myocardial infarction, stroke), epilepsy and increased overall mortality in adulthood. Studies show that not only previous experience but also the stress of being taken into care is triggers for this. Conclusion: Information about a previous institutionalisation can hence be important for internal medical practice. The available scientific literature shows heterogeneous study methodology and no group of people with experience of out-of-home-placement has yet been scientifically accompanied for a long time period. Further studies on this could help to better weigh up the consequences of omitting and conducting an intervention for child/youth protection as well as to improve the medical care for this group of people.

Effect of interrupted aging on mechanical properties and corrosion resistance of 7A75 aluminum alloy

The effects of interrupted aging on mechanical properties and corrosion resistance of 7A75 aluminum alloy extruded bar were investigated through various analyses,including electrical conductivity,mechanical properties,local corrosion properties,and slow strain rate tensile stress corrosion tests.Microstructure characterization techniques such as metallographic microscopy,scanning electron microscopy(SEM),and transmission electron microscopy(TEM)were also employed.The results indicate that the tensile strength of the alloy produced by T6I6 aging is similar to that produced by T6I4 aging,and it even exceeds 700 MPa.Furthermore,the yield strength increases by 52.7 MPa,reaching 654.8 MPa after T6I6 aging treatment.The maximum depths of intergranular corrosion(IGC)and exfoliation corrosion(EXCO)decrease from 116.3 and 468.5μm to 89.5 and 324.3μm,respectively.The stress corrosion factor also decreases from 2.1%to 1.6%.These findings suggest that the alloy treated with T6I6 aging exhibits both high strength and excellent stress corrosion cracking resistance.Similarly,when the alloy is treated with T6I4,T6I6 and T6I7 aging,the sizes of grain boundary precipitates(GBPs)are found to be 5.2,18.4,and 32.8 nm,respectively.The sizes of matrix precipitates are 4.8,5.7 and 15.7 nm,respectively.The atomic fractions of Zn in GBPs are 9.92 at.%,8.23 at.%and 6.87 at.%,respectively,while the atomic fractions of Mg are 12.66 at.%,8.43 at.%and 7.00 at.%,respectively.Additionally,the atomic fractions of Cu are 1.83 at.%,2.47 at.%and 3.41 at.%,respectively.

Pulsatile gonadotropin-releasing hormone therapy induces spermatogenesis in pituitary stalk interruption syndrome:A case report and review of the literature

BACKGROUND Pituitary stalk interruption syndrome(PSIS)is a rare anatomical defect of the pituitary gland falling under the spectrum of holoprosencephaly phenotypes.It is characterized by a deficiency in anterior pituitary hormones,such as growth hormone,gonadotropins,and thyroid hormones.Due to the syndrome's rarity and nonspecific manifestations,there is a lack of standardized treatment strategies.Consequently,early diagnosis through imaging and on-time intervention are crucial for improving patients’outcomes.CASE SUMMARY A 30-year-old man presented with absent secondary sexual characteristics and azoospermia.Laboratory evaluation revealed a deficiency in gonadotropins,while thyroid function was mostly within normal ranges.Magnetic resonance imaging of the pituitary gland showed pituitary stalk agenesis,hypoplasia of the anterior pituitary,and ectopic posterior pituitary,leading to the diagnosis of PSIS.Initially,the patient underwent 6 mo of gonadotropin therapy without significant changes in hormone levels and secondary sexual characteristics.Pulsatile gonadotropin-releasing hormone therapy was then administered,resulting in the detection of sperm in the semen analysis within 3 mo.After 6 mo,routine semen tests showed normal semen quality.The couple faced challenges in conceiving due to abstinence and underwent three cycles of artificial insemination,which was unsuccessful.They also attempted in vitro fertilization,but unfortunately,the woman experienced a miscarriage 10 wk after the embryo transfer.CONCLUSION Early detection,accurate diagnosis,and timely treatment are crucial in improving the quality of life and fertility of PSIS patients.

Pituitary stalk interruption syndrome complicated with liver cirrhosis:A case report

BACKGROUND Pituitary stalk interruption syndrome(PSIS)is a rare disorder,often characterized by delayed growth and development,short stature,and hypogonadism as the main clinical manifestations.It is not clear whether PSIS can lead to liver cirrhosis.CASE SUMMARY This paper reported a case of liver cirrhosis of unknown origin.The patient was admitted to Beijing Ditan Hospital Affiliated to Capital Medical University in November 2023.The diagnosis of PSIS complicated with liver cirrhosis was established after a series of blood tests and pituitary magnetic resonance imaging examination.CONCLUSION We also reviewed the literature from both domestic and international sources to deepen the clinical understanding of PSIS in conjunction with liver cirrhosis among medical practitioners.

多学科协作团队干预在局麻下玻璃体切除术患者中的应用

目的探讨多学科协作团队干预在局麻下玻璃体切除术患者中的应用效果。方法采用历史对照研究,选取郑州大学第一附属医院2022年2月14日至2022年3月25日拟行多学科协作团队干预的玻璃体切除术治疗患者100例作为观察组;另收集医院2021年9月20日至2021年10月17日接受常规干预的玻璃体切除术治疗患者198例资料作为对照组,患者治疗期间接受常规干预。统计并对比两组单台手术平均中断次数、并发症、手术时间及离院时间。结果对照组单台手术平均中断次数3.00(3.00,4.00)次,观察组单台手术平均中断次数1.00(1.00,2.00)次;观察组单台手术平均中断次数显著小于对照组(Z=13.257,P<0.001)。观察组干预期间并发症发生率低于对照组(P<0.05)。观察组手术时间、手术结束至离院时间均短于对照组(P<0.05)。结论多学科协作团队干预可显著减少局麻下玻璃体切除术中平均中断次数,降低术后并发症发生风险,缩短手术时间及手术结束至离院时间。

Analyses of unified congestion measures for interrupted traffic flow on urban roads

To study the congestion of interrupted flow on urban roads, a comprehensive evaluation method is proposed. First, based on the results of correlation analysis between different parameters of interrupted flow, the traffic parameters of interrupted traffic flow are divided into two categories： the basic parameters and the operation parameters. Polynomial regression is used to formulize the nonlinear relationships between the basic parameters and the operation parameters. Then, the congestion model incorporating both operational and volume characteristics of traffic flow is proposed. The inputs of the model are the basic parameters, while the output is a dimensionless index value between 0 and 1. Finally, the proposed methods are compared with existing evaluation measures of congestion. Results show that the proposed indices can capture the variation of both the basic parameters and the operation parameters, which is more balanced compared with the existing evaluation measures.

并联电容对真空灭弧室内部电位分布的改善作用

真空灭弧室的绝缘水平是影响其性能和可靠性的一个关键因素。现有研究发现,真空灭弧室放入接地金属外壳内,受对地杂散电容的影响,屏蔽罩电位会出现偏移现象,导致灭弧室绝缘水平下降。针对此问题,该文通过建立真空灭弧室等效电路模型,研究了通过并联电容调整屏蔽罩电位对灭弧室内部电位分布的改善作用,并通过实验测量了真空灭弧室屏蔽罩悬浮电位,验证了并联电容方法的改善作用。研究结果表明,真空灭弧室的杂散电容约为十几pF量级,通过为灭弧室并联百pF量级的电容,可以有效地改善其内部的电位偏移现象。实验中所测量的真空灭弧室在自然状态下,其主屏蔽罩电位约为34%总电压,对该灭弧室并联500 pF电容,可将其主屏蔽罩电位调整至49%总电压。此外,针对具有多级悬浮屏蔽罩结构的真空灭弧室,提出并对比了两种电容并联方案的差异,得到只调整主屏蔽罩电位的电容并联方式是更为理想的选择。

异常燃烧噪声导致的柴油机启动异响研究

针对搭载2.0 L涡轮增压柴油机的某皮卡车型在启动工况出现的异响问题进行排查与诊断,首先利用发动机消声室台架复现了异响,在台架进行异响信号的NVH测试,通过声频回放及信号滤波,确认异响为13 kHz宽频噪声;再通过逐缸断油方法,发现仅对第4缸断油后,启动异响完全消失,评估异响可能与第4缸燃烧相关;运用Kibox燃烧分析仪,对启动工况各缸燃烧特性进行分析,发现异响出现在第4缸最先喷油的情况下,且最大压力升高率达42 Bar/(◦),确认抱怨异响为燃烧噪声;进一步测试各缸物理喷油信号,发现第4缸无预喷信号,仅有主喷信号;通过分析该机型同步信号识别方式和喷油程序底层逻辑,发现当前逻辑中,启动过程第一次识别同步信号的时刻在第4缸预喷程序计算时刻之后,导致预喷计算失败;最终将底层喷油中断程序往后推60◦曲轴转角,保证了启动工况第4缸预喷顺利喷射,异响得以解决,且对发动机性能无影响。

湖南省带量采购和分级管理政策对碳青霉烯类抗生素利用的影响

目的探索抗菌药物带量采购和分级管理政策对碳青霉烯类抗生素利用的影响。方法采用Mann-Kendall趋势检验分析各级医疗机构碳青霉烯类抗生素用药频度(DDDs)、采购金额(Cost)、药品日均费用(DDDc)、每天每1000居民用药频度(DID)的变化趋势,以2020年5月1日为带量采购政策的干预分界点,以2021年9月作为分级管理目录的干预分界点,采用间断时间序列分析法研究带量采购和分级管理政策对碳青霉烯类抗生素临床用药的影响。结果在带量采购政策执行后,碳青霉烯类抗生素DDDs、DID明显上升,但长期趋势变化不显著;与政策执行前相比,碳青霉烯类抗生素的Cost和DDDc瞬时下降,DDDc长期趋势变化显著,但Cost长期趋势变化不显著。分级管理目录更新后,碳青霉烯类抗生素DDDs、Cost瞬时下降,但长期下降趋势不显著,并且DDDc呈长期上升趋势。结论带量采购政策降低了碳青霉烯类抗生素DDDc,短期内降低了Cost;但对DDDs、Cost、DID的长期影响有限;分级管理对医疗机构碳青霉烯类抗生素的利用影响有限。

STIL enhances the development of lung adenocarcinoma by regulating the glycolysis pathway

Background:To investigate SCL/TAL 1 interrupting locus(STIL)’s role and prognostic significance in lung adenocarcinoma(LUAD)progression,we examined STIL and E2 promoter binding factor 1(E2F1)expression and their impacts on LUAD prognosis using Gene Expression Profiling Interactive Analysis(GEPIA).Methods:Functional assays including CCK-8,wound-healing,5-ethynyl-2-deoxyuridine(EdU),Transwell assays,and flow cytometry,elucidated STIL and E2F1’s effects on cell viability,proliferation,apoptosis,and migration.Gene set enrichment analysis(GSEA)identified potential pathways,while metabolic assays assessed glucose metabolism.Results:Our findings reveal that STIL and E2F1 are overexpressed in LUAD,correlating with adverse outcomes.It enhances cell proliferation,migration,and invasion,and suppresses apoptosis,activating downstream of E2F1.Silencing E2F1 reversed the promotion effect of the STIL overexpression on cell viability and invasiveness.Importantly,STIL modulates glycolysis,influencing glucose consumption,lactate production,and energy balance in LUAD cells.Conclusion:Our model,incorporating STIL,age,and disease stage,robustly predicts patient prognosis,underscored STIL’s pivotal role in LUAD pathogenesis through metabolic reprogramming.This comprehensive approach not only confirms STIL’s prognostic value but also highlights its potential as a therapeutic target in LUAD.

Interrupt CW Approach for IF Video Signal Real Time Simulating and Its Validity

To determine the feasibility and practicability of interrupt continuous wave (CW) approach proposed for real time simulating radar intermediate frequency(IF) video signal, theoretical analysis and computer simulation were used. Phases at two linked points between the end and beginning of adjoined frames are always consistent; the bias Doppler frequency for the time delay of A/D sampling start responds to that for target acceleration. No digital phase compensation is required at continuous points, and the interrupt CW approach has apparently practical values.

医院前置审方系统应用效果评价

目的探索前置审方系统在门、急诊处方合格率上的提升效果及存在问题。方法本研究采用中断时间序列方法,收集武汉市汉口医院2022年5月至2023年4月(前置审方系统应用前)、2023年5月至2024年4月(前置审方系统应用后)门、急诊处方的审方数据,分析前置审方系统应用前后处方合格率的瞬时和趋势变化情况。结果前置审方系统应用前,处方合格率每月增加0.081;前置审方系统应用后的第1个月,处方瞬时合格率显著增加7.903;随后合格率的趋势改变量显著增加0.709;前置审方系统应用后处方合格率每月显著增加0.790。结论前置审方系统的应用能提升门、急诊处方合格率,促进形成合理用药趋势,系统运行数据能指引优化完善审方规则。

美国大学“可免试入学”选才政策的演进逻辑

美国大学“可免试入学”选才政策打破了传统招生对标准化考试成绩的依赖,对提升高等教育公共服务的可及性产生了重要影响。基于间断-均衡理论视角,可深入剖析政策变迁中政策图景、政策场域、政策垄断等核心要素的动态变化与作用机制。美国大学“可免试入学”政策历经标准化考试成绩依赖逐步确立与主导阶段、打破标准化考试成绩桎梏的潮流逆转阶段、以多元评价标准录取决策的理念重塑阶段。从动因解释来看,主要受大学招生决策主体注意力的转移、焦点事件强力冲击、经济社会情境改变的影响。在深入推进新高考综合改革的背景下,我国大学可从深度推进新高考综合评价、保障一流大学办学自主和扩大招生自主权、提高招生过程透明度等三个方面突破。

有Bernoulli中断休假和随机启动时间的N-策略多重休假M=G=1排队的队长分析

本文研究一个有Bernoulli中断休假和随机启动时间的N-策略多重休假M/G/1排队模型,其中Bernoulli中断休假是指:如果在休假中有顾客到达,服务员以概率p(0≤p≤1)立即中断休假回到系统中并启动服务设施,以概率(1−p)不中断休假直到此次休假结束后才回到系统启动服务设施.当系统的启动完成后,若系统中顾客数大于等于事先设置的阈值N(≥1),则服务员开始为顾客服务直到系统再次变空.运用全概率分解技术和更新过程理论讨论了系统在时刻t队长的瞬态概率分布,得到了队长瞬态概率分布的拉普拉斯变换表达式.在瞬态分析的基础上,使用洛必达法则和一些代数运算推导出了队长稳态概率分布的递推表达式,以及其它一些排队指标,如队长稳态概率分布的母函数、平均队长和附加队长的概率分布等.最后,讨论了一些特殊情形.

DRG政策对公立医院分级诊疗效果的影响及评价研究

目的:从急慢分治和双向转诊的角度量化评估DRG政策对各级公立医院分级诊疗效果的影响。方法:收集2016-2023年桂林市卫生信息季度数据,采用单组和多组间断时间序列(ITS)模型分析政策实施前后各级医院分级诊疗效果。结果:单组ITS结果显示,DRG政策实施后公立医院住院天数呈下降趋势,住院费用及手术比例均由升反降,CMI值由降反升。二级医院三四级手术比例在DRG政策实施前逐季上升0.55%(P<0.01),实施后逐季下降0.8%(P<0.01);而三级医院则相反,实施前逐季下降0.68%(P<0.01),实施后逐季上升0.85%(P<0.01)。多组ITS结果显示三级医院CMI值、三四级手术比例在DRG政策实施后上升趋势均高于二级医院。门诊人数/住院人数、门诊占比在实施前后以及二三级医院之间没有明显差异(P>0.05)。结论:DRG政策提升了公立医院服务质量与效率,促进了急慢分治和双向转诊。但DRG政策对二级医院及各级医院门诊分级诊疗效果有限。二级医院应加强精细化管理并积极参与医联体建设;同时将DRG政策引入门诊医疗服务,积极推行门诊按人头付费,从而不断完善分级诊疗体系。