Electron Shape Calculated for the Dual-Charge Dual-Mass Model

A model for the internal structure of the electron using classical physics equations has been previously published by the author. The model employs both positive and negative charges and positive and negative masses. The internal attributes of the electron structure were calculated for both ring and spherical shapes. Further examination of the model reveals an instability for the ring shape. The spherical shape appears to be stable, but relies on tensile or compressive forces of the electron material for stability. The model is modified in this document to eliminate the dependency on material forces. Uniform stability is provided solely by balancing electrical and centrifugal forces. This stability is achieved by slightly elongating the sphere along the spin axis to create a prolate ellipsoid. The semi-major axis of the ellipsoid is the spin axis of the electron, and is calculated to be 1.20% longer than the semi-minor axis, which is the radius of the equator. Although the shape deviates slightly from a perfect sphere, the electric dipole moment is zero. In the author’s previously published document, the attributes of the internal components of the electron, such as charge and mass, were calculated and expressed as ratios to the classically measured values for the composite electron. It is interesting to note that all of these ratios are nearly the same as the inverse of the Fine Structure Constant, with differences of less than 15%. The electron model assumed that the outer surface charge was fixed and uniform. By allowing the charge to be mobile and the shape to have a particular ellipticity, it is shown that the calculated charge and mass ratios for the model can be exactly equal to the Fine Structure Constant and the Constant plus one. The electron radius predicted by the model is 15% greater than the Classical Electron Radius.

Mass thickness measurements for dual-component samples utilizing equivalent energy of X-rays

In this paper,equivalent energy method is introduced for measuring mass thickness of dual-component samples using dual-energy X-rays.Approximately,the method adopts equivalent mass attenuation coefficients of the two components in mass thickness measurements for dual-component samples,in a certain range of thicknesses.Feasibility of the method is proven by numerical calculations and Monte Carlo simulations(EGSnrc package).The results of absorption experiments using an X-ray machine at tube voltages of 30 and 45 kV,the relative errors are less than 5%between the nominal and detected values.Also,optical low energy is discussed at given high voltages.

双质量飞轮减振性能对整车NVH影响的研究

双质量飞轮作为汽车传动系统中的重要部件,主要功能就是减振降噪,提升整车NVH水平,本文通过整车测试及传动系统模拟仿真计算,对双质量飞轮减振性能进行优化,进一步提升整车NVH水平。

考虑滑块动态特性的变质心四旋翼无人机双回路控制

针对滑块动态特性引入的附加干扰力矩造成系统姿态抖动强烈的问题,开展变质心四旋翼无人机滑块参数设计与姿态/伺服双回路控制研究。通过建立双滑块变质心四旋翼无人机八自由度运动模型,明确了滑块的引入对系统的影响,给出了与滑块动态特性相关的各项附加干扰力矩;分析并设计了滑块的安装位置、质量以及行程等参数,降低滑块对系统的耦合与干扰;最后以滑块驱动力作为控制量,设计了姿态/伺服双回路动态滑模控制器,同时利用非线性扰动观测器对复合扰动进行估计和补偿,并进行了仿真试验。仿真结果表明,在考虑滑块动态特性的情况下,所设计的控制器能够实现对变质心四旋翼无人机的姿态控制,并具有良好的抗干扰性能与鲁棒性。

生物电阻抗法测量18~42岁成人四肢骨骼肌质量的准确性评价

目的评价生物电阻抗法(bioelectrical impedance analysis,BIA)测量成人四肢骨骼肌质量(appendicular skeletal muscle mass,ASM)的准确性。方法采用方便抽样法,于2021年4月至2022年9月在广州全市招募836名18~42岁成人,采用BIA与双能X线吸收法(dual-energy X-ray absorptiometry,DXA)同步检测ASM。以DXA为标准方法,通过组内相关系数以及在对数变换数据中进行Bland-Altman分析判断BIA与DXA所测值的一致性,以此评价BIA测量ASM的准确性。绘制受试者工作特征曲线,评价BIA识别低肌肉质量的诊断价值。结果最终纳入774名研究对象。男、女性中两法所测ASM组内相关系数分别为0.774和0.667。男、女性中BIA与DXA所测ASM比值均值(一致性限)分别为0.94(0.80~1.10)和0.91(0.78~1.05)。BIA识别男、女性低肌肉质量的曲线下面积分别0.91和0.94。BIA判断男、女性低肌肉质量的Z值最佳界值分别为-0.57和-0.66,男性中BIA识别低肌肉质量的灵敏度、特异度分别为82.5%、86.0%,女性中分别为86.8%、93.8%。结论BIA与DXA所测成人四肢骨骼肌质量的一致性尚可,且BIA识别18~42岁成人低肌肉质量的诊断价值较好。

某双油路离心式喷嘴雾化性能分析

燃油喷嘴的雾化对于解决航空发动机燃烧室问题是至关重要的,为探究某双油路离心式喷嘴的雾化性能,运用两相界面追踪流体体积(Volume of Fluid,简称VOF)方法对该喷嘴的内外部流场进行数值仿真。以双油路离心喷嘴的雾化锥角、质量流率以及液膜厚度作为雾化性能指标,分别模拟出主油路单独供油、副油路单独供油以及主副油路同时供油三种不同工作模式在不同压差条件下喷嘴燃油流动的稳态情况,获得双油路离心喷嘴的雾化性能指标并对其影响规律进行研究。结果显示:数值仿真能较好地模拟出喷嘴的雾化特性,随着压差增大,扩口式主油路单独工作时的雾化锥角减小,平口式副油路单独工作时的雾化锥角增大。当主、副油路同时工作时,雾化锥角随压差的增大而增大且始终处于单路单独工作时的雾化锥角之间;质量流率随着压差的增大而增大且增幅逐渐减缓;液膜厚度在低压区随压差的增大而迅速减小,随后趋于稳定。

Prevalence and outcome of sarcopenia in non-alcoholic fatty liver disease

BACKGROUND Nonalcoholic fatty liver disease(NAFLD)includes a spectrum of conditions,progressing from mild steatosis to advanced fibrosis.Sarcopenia,characterized by decreased muscle strength and mass,shares common pathophysiological traits with NAFLD.An association exists between sarcopenia and increased NAFLD prevalence.However,data on the prevalence of sarcopenia in NAFLD and its impact on the outcomes of NAFLD remain inconsistent.AIM To analyze the prevalence and outcomes of sarcopenia in patients with NAFLD.METHODS We conducted a comprehensive search for relevant studies in MEDLINE,Embase,and Scopus from their inception to June 2023.We included studies that focused on patients with NAFLD,reported the prevalence of sarcopenia as the primary outcome,and examined secondary outcomes,such as liver fibrosis and other adverse events.We also used the Newcastle-Ottawa scale for quality assessment.RESULTS Of the 29 studies included,the prevalence of sarcopenia in NAFLD varied widely(1.6%to 63.0%),with 20 studies reporting a prevalence of more than 10.0%.Substantial heterogeneity was noted in the measurement modalities for sarcopenia.Sarcopenia was associated with a higher risk of advanced fibrosis(odd ratio:1.97,95%confidence interval:1.44-2.70).Increased odds were consistently observed in fibrosis assessment through biopsy,NAFLD fibrosis score/body mass index,aspartate aminotransferase to alanine aminotransferase ratio,diabetes(BARD)score,and transient elastography,whereas the fibrosis-4 score showed no such association.Sarcopenia in NAFLD was associated with a higher risk of steatohepatitis,insulin resistance,cardiovascular risks,and mortality.CONCLUSION This systematic review highlights the critical need for standardized diagnostic criteria and measurement methods for sarcopenia in NAFLD patients.The variability in study designs and assessment methods for sarcopenia and liver fibrosis may account for the inconsistent findings.This review demonstrates the multidimensional impact of sarcopenia on NAFLD,indicating its importance beyond liver-related events to include cardiovascular risks,mortality,and metabolic complications.

某DCT变速箱输入轴扭振幅值优化

汽车传动系的扭振会造成车内轰鸣或异响,扭振激励一般来自发动机的工作主阶次,通过扭振减振器向变速箱传递。因此,变速箱输入轴的扭振幅值是控制整个传动系扭振问题的第一要素。某款乘用车搭载6速湿式双离合变速箱(Wet Double Clutch Transmission,WDCT),测得2挡至6挡的变速箱输入轴扭振幅值最大达494.38 rad/s^(2),不满足设计要求400 rad/s^(2)。为解决变速箱输入轴扭振幅值过大问题,利用AMESim软件搭建包含双质量飞轮扭振减振器的全油门驱动工况下的扭振分析模型,以实车采集的发动机转速波动信号为激励源,通过仿真分析确定了双质量飞轮的初、次级质量转动惯量、扭转刚度、基础阻尼力矩及自由转角对变速箱输入轴扭振幅值的影响;通过正交试验,得到了传动系的优化设计方案,并通过实车验证了优化方案的有效性。该研究方法和思路为包含双质量飞轮扭振减振器的汽车传动系扭振优化提供了解决方案。

探究双层光谱探测器CT在鉴别可切除胰腺导管腺癌与肿块型慢性胰腺炎方面的价值

背景与目的:胰腺导管腺癌(pancreatic ductal adenocarcinoma,PDAC)与肿块型慢性胰腺炎(mass-forming chronic pancreatitis,MFCP)的准确鉴别具有较大的临床意义。双层光谱探测器计算机体层成像(dual-layer spectral detector computedtomography,DLCT)在胰腺方面的应用已有一定的探索。本研究旨在探究DLCT在鉴别可切除PDAC与MFCP方面的价值。方法:回顾性分析2021年9月1日—2023年5月31日复旦大学附属肿瘤医院收治的33例可切除PDAC和19例MFCP患者的临床影像学资料,术前行DLCT增强扫描,扫描期相包括动脉期(arterial phase,AP)、实质期(parenchymal phase,PP)和静脉期(venous phase,VP)。计算DLCT定量指标,包括衰变强化分数(attenuation enhancement fraction,AEF)、病灶胰腺实质比(lesion to parenchyma ratio,LPR)、碘强化分数(iodine enhancement fraction,IEF)。采用独立样本t检验或χ^(2)检验进行统计学分析,采用二元逻辑回归进行单因素及多因素分析,采用受试者工作特征(receiver operator characteristic,ROC)曲线进行效能评价。P<0.05为差异有统计学意义。结果:在PDAC与MFCP之间,AEF_AP/PP、LPR_(40)_VP、IEF_PP/VP、糖类抗原19-9(carbohydrate antigen 19-9,CA19-9)及双管征的差异有统计学意义(P<0.05)。LPR_(40)_VP与IEF_PP/VP构成的融合模型具有最佳的鉴别效能,优于CA19-9、双管征及AEF_AP/PP(P<0.05),其曲线下面积(area under curve,AUC)为0.841,灵敏度为90%,特异度为73%,准确度为79%。结论:DLCT在鉴别可切除PDAC与MFCP方面具有一定潜能,光谱定量参数可以弥补CA19-9、常规CT在鉴别可切除PDAC与MFCP方面的不足。

双质量块薄膜型声学超材料的隔声特性分析

基于超材料隔声原理设计了一种双质量块薄膜型声学超材料结构,通过试验和有限元方法对其隔声性能进行了研究,并基于数值方法进一步研究了其隔声特性影响因素。结果表明:所设计的双质量块薄膜型声学超材料在中低频区域能产生两个传声损失峰值;增加薄膜上质量块半径或厚度会使传声损失曲线整体向低频区域移动;增加质量块之间距离会使第一个隔声峰对应频率和第二隔声峰对应频率出现先减小后增大的变化规律,当质量块之间距离在1.2 mm左右时,第一隔声峰对应频率的极小值为440 Hz,当质量块之间距离在2.4 mm左右时,第二隔声峰对应频率的极小值为685Hz;减小薄膜厚度或预应力会使传声损失曲线整体向低频区域移动。

双重液液萃取QuEChERS-HPLC/MS/MS法测定果蔬及粮食中噁唑酰草胺残留

样品经正己烷第一次萃取后,氮吹至干,再由乙腈-水第二次萃取,乙腈层经改进的QuEChERS方法净化,以0.1%(V/V)甲酸水溶液-乙腈为流动相梯度洗脱,C18色谱柱分离,HPLC-MS/MS多反应监测(MRM)模式测定,基质匹配外标法定量。结果表明,在9种基质(葡萄、梨、甘蔗、黄瓜、芹菜、土豆、大豆、玉米、大米)中,噁唑酰草胺在1.0~50.0ng/mL范围内的线性关系均较好(r>0.999),定量限在0.5μg/kg~1.0μg/kg;在1.0、5.0、10.0μg/kg3个添加水平下,平均回收率为63.9%~113.7%,相对标准偏差(relative standard deviation,RSD)为1.0%~22.2%(n=6)。该方法快速、灵敏、简便、准确,可用于多种植源性食品中噁唑酰草胺农药残留的定性和定量检测。

1.6T GDI发动机用双质量飞轮扭转特性研究

以某1.6T汽油直射(GDI)发动机车型为研究对象,设计了适用于该款车型的双质量飞轮,以提高车辆舒适性。首先根据双质量飞轮工作原理,设计了双质量飞轮的内、外弧形弹簧,以保证双质量飞轮的扭转特性,并利用CATIA建立了其3维模型。然后为保证双质量飞轮的性能,对所设计的弧形弹簧刚度、应力及双质量飞轮的扭矩容量、温升进行了校核,结果表明设计满足要求。最后,通过试验验证了设计的双质量飞轮的耐高速性能、疲劳性能。

Correlation between Low Tube Voltage in Dual Source CT Coronary Artery Imaging with Image Quality and Radiation Dose

The influence of low tube voltage in dual source CT（DSCT） coronary artery imaging on image quality and radiation dose and its application value in clinical practice were investigated. Totally, 300 cases of chest pain with low body mass index（BMI 〈18.5 kg/m2） subjected to DSCT coronary artery imaging were prospectively enrolled. The heart rate in all patients were greater than 65/min. The retrospective ECG gated scanning mode and simple random sampling method were used to assign the patients into groups A, B and C（n=100 each）. The patients in groups A, B and C experienced 120-, 100-, and 80-kV tube voltage imaging respectively, and the image quality was evaluated. The CT volume dose index（CTDIvol） and dose length product（DLP） were recorded, and the effective dose（ED） was calculated in each group. The image quality scores and radiation doses in groups were compared, and the influence of tube voltage on image quality and radiation dose was analyzed. The results showed that the excellent rate of image quality in groups A, B and C was 95.69%, 94.72% and 96.33% respectively with the difference being not statistically significant among the three groups（P〉0.05）. The CTDIvol values in groups A, B and C were 51.35±12.21, 21.28±7.13 and 6.34±3.34 mGy, respectively, with the difference being statistically significant（P〈0.05）. The ED values in groups A, B and C were 9.27±1.63, 4.56±2.29 and 2.29±1.69 mSv, respectively, with the difference being statistically significant（P〈0.05）. It was suggested that for the patients with low BMI, the application of DSCT coronary artery imaging with low tube voltage can obtain satisfactory image quality, and simultaneously, significantly reduce the radiation dose.

From a Dual Einstein-Kaluza Spacetime to ‘tHooft Renormalon and the Reality of Accelerated Cosmic Expansion

We use a dual Einstein-Kaluza spacetime to calculate the exact energy density of dark energy and dark matter using a novel topological computation method. Starting from the said spacetime and ‘tHooft’s topological renormalon as well as the corresponding symmetry group, we show how the zero set quantum particle and the empty set quantum wave interact with the vacuum and give rise to pure dark energy and pure dark matter all along with ordinary energy density of the cosmos. The consistency of the exact calculation and the accurate observations attests to the reality of ‘tHooft’s renormalon dark matter, pure dark energy and accelerated cosmic expansion.

Rapid Framing Mass Storage System on the Internet

Mass storage system is now very important for storing huge volume of data in many application system such as VOD systems, electronic library, scientific computation and so on. Besides the storage device and network devices, the real performance of mass storage system is greatly influenced by the connection way between the host and storage system. Here we propose a new design of mass storage system by promoting the storage devices' functions and involving, them directly into data delivering. It can easily meet the demands both for capacity and I/O bandwidth in those applications, and has better service quality and performance compared with the traditional system in delivering mass data over network.

Dynamic Failure Model of Thin Coal and Rock Mass under Uniform Impact Load

During the excavation of deep coal and rock mass, the radial stress of the free face changes from three-dimensional compression state to two-dimensional stress, bearing the combined action of dynamic disturbance and static load at the same time. With that, many mines suffer from dynamic disasters, such as coal and gas outburst, rock burst and rock caving during deep mining excavation, which is often accompanied by plate crack, spalling and other disasters, seriously affecting the stability of stope and roadway. Taking thin rectangular coal and rock mass as the research object, the dual equation of the free vibration was derived and the exact solution model of the free vibration was established with the use of Hamilton dual system. Based on the action characteristics of the uniform impact load, the effective mode of the forced vibration was obtained by using the Duhamel integral principle and the orthogonality of the mode function. Based on the third strength theory and the numerical simulation results, the dynamic damage process and development trend of coal and rock mass were analyzed under uniform impact load. It was concluded that the starting position of dynamic damage can be judged by the first order main mode, and the development direction and trend of the damage can be judged by the fifth and sixth order main modes. It was concluded that the vibration mode functions of coal and rock mass with four side fixed (C-C-C-C), the two sides fixed and simply supported on the other (S-C-S-C) are mainly composed of three modes that are the first order (dominant frequency), the fifth order and the sixth order, from which the dynamic damage mechanism is preliminarily studied.

A DATA ACQUISITION SYSTEM FOR ACCELERATOR MASS SPECTROMETRY

A single and dual parameter data acquisition, ion beam measurements and control system for accelerator mass spectrometry is described. The system hardware has been constructed with the advantage of the lower cost and higher reliability. It is provided with varieties of functions such as selecting acquisition mode carrying out the multiple display, analyzing data and especially viewing isometric spectrum at different directions. It can also be used for ordinary nuclear spectrum system.

水封石油洞库污染物运移规律研究

水封石油洞库储油可能造成地下水污染。明晰石油污染物在裂隙岩体中的运移规律是库区地下水污染防控的前提。为揭示石油污染物在洞周围岩地下水中的运移规律,基于裂隙-孔隙双重介质模型,采用数值模拟方法研究了石油中的特征污染物——苯的运移扩散过程,并分析了裂隙倾角、裂隙开度、基质渗透率和纵向弥散度对苯运移规律的影响。研究表明:储库正常运行50 a后,苯的迁移被限制在较小的范围内,不会到达水幕系统,也不会进入到地面表层下的水体中。在长期运行条件下,相邻洞周围岩中的污染晕可相互连通,并将引起相邻洞罐中油品污染物之间的交叉污染。苯的竖向污染距离对纵向弥散度和裂隙倾角大小敏感性强,而对裂隙开度和基质渗透率的敏感性较弱。洞室间岩柱中轴线上苯的最大浓度对裂隙倾角最为敏感,且随裂隙倾角和基质渗透率的增大而减小,随纵向弥散度和裂隙开度的增加而增大。

汽车双质量飞轮扭振特性仿真分析与优化

双质量飞轮能够将发动机的扭转振动与传动系隔离开来,使其运转时的噪声和车身振动得以改善,提高车辆舒适性。针对汽车舒适性要求不断提高以及研发时间短、经费高的现状,用仿真技术对双质量飞轮进行模拟和优化设计。分析双质量飞轮仿真的前提条件和优化方法,对分别带有二级弧形弹簧、内置减振器、离心摆等结构的双质量飞轮进行优化比较,得出最佳的设计方案。

定量超声测定法与双能X线吸收法评估18~40岁成人骨健康的比较分析

目的比较定量超声测定法(QUS)与双能X线吸收法(DXA)测量广州市18~40岁成人骨密度的一致性,评估QUS识别低骨量的诊断价值。方法在731名研究对象中,采用DXA测量骨密度(BMD),QUS测量超声传导速度(SOS)。采用Bland-Altman分析评价SOS与BMD Z值的一致性。以BMD Z≤-2.00作为低骨量的诊断标准,绘制QUS的受试者工作特征曲线,并计算曲线下面积(AUC)以及SOS Z值最佳截断值的灵敏度、特异度和正确诊断指数。结果Bland-Altman分析结果显示,男、女性的SOS和BMD Z值的均值差值分别为1.27(-0.94~3.47)和0.93(-1.33~3.18)。男、女性中SOS Z值诊断低骨量的AUC分别为0.734(95%CI=0.380~0.788)、0.679(95%CI=0.625~0.732)。男性中,低骨量的SOS Z值最佳截断值为-0.35,灵敏度、特异度和正确诊断指数分别为64.1%、68.6%和0.327;女性中,低骨量的SOS Z值最佳截断值为-1.14,灵敏度、特异度和正确诊断指数分别为73.9%、54.8%和0.285。结论广州市18~40岁成人中,QUS与DXA诊断骨密度的一致性欠佳,但QUS在识别低骨量上的应用价值尚可。