Design of insulation support system of 120 keV positive ion source accelerator

In order to support the physical research on the EAST tokamak,a new positive ion source with designed beam energy of 120 keV was proposed to be developed.Accelerator structure is one of the key components of the ion source.Through the finite element analysis method,the electrostatic analyses of insulators and grid plates were carried out,the material and structure parameters of insulators were determined.The maximum electric field around each insulator is about 4 kV/mm,and the maximum electric field between grids is about 14 kV/mm,which can meet the 120 keV withstand voltage holding.The insulation system for the positive ion source accelerator with 120 keV is designed,and the connection and basic parameters of insulators and support flanges are analyzed and determined.

POSITIVE DEFINITE KERNEL IN SUPPORT VECTOR MACHINE(SVM)

The relationship among Mercer kernel, reproducing kernel and positive definite kernel in support vector machine （SVM） is proved and their roles in SVM are discussed. The quadratic form of the kernel matrix is used to confirm the positive definiteness and their construction. Based on the Bochner theorem, some translation invariant kernels are checked in their Fourier domain. Some rotation invariant radial kernels are inspected according to the Schoenberg theorem. Finally, the construction of discrete scaling and wavelet kernels, the kernel selection and the kernel parameter learning are discussed.

Backward Support Computation Method for Positive and Negative Frequent Itemset Mining

Association rules mining is a major data mining field that leads to discovery of associations and correlations among items in today’s big data environment. The conventional association rule mining focuses mainly on positive itemsets generated from frequently occurring itemsets (PFIS). However, there has been a significant study focused on infrequent itemsets with utilization of negative association rules to mine interesting frequent itemsets (NFIS) from transactions. In this work, we propose an efficient backward calculating negative frequent itemset algorithm namely EBC-NFIS for computing backward supports that can extract both positive and negative frequent itemsets synchronously from dataset. EBC-NFIS algorithm is based on popular e-NFIS algorithm that computes supports of negative itemsets from the supports of positive itemsets. The proposed algorithm makes use of previously computed supports from memory to minimize the computation time. In addition, association rules, i.e. positive and negative association rules (PNARs) are generated from discovered frequent itemsets using EBC-NFIS algorithm. The efficiency of the proposed algorithm is verified by several experiments and comparing results with e-NFIS algorithm. The experimental results confirm that the proposed algorithm successfully discovers NFIS and PNARs and runs significantly faster than conventional e-NFIS algorithm.

Support and Positioning Mechanism of a Detection Robot inside a Spherical Tank

Large pressure equipment needs to be tested regularly to ensure safe operation;wall-climbing robots can carry the necessary tools to inspect spherical tanks,such as cameras and non-destructive testing equipment.However,a wall-climbing robot inside a spherical tank cannot be accurately positioned owing to the particularity of the spherical tank structure.This paper proposes a passive support and positioning mechanism fixed in a spherical tank to improve the adsorption capacity and positioning accuracy of the inspection robot.The main body of the mechanism was designed as a truss composed of carbon fiber telescopic rods and can work in spherical tanks with diameters of 4.6-15.7 m.The structural strength,stiffness,and stability of the mechanism are analyzed via force and deformation simulations.By constructing a mathematical model of the support and positioning mechanism,the influence of structural deformation on the supporting capacity is analyzed and calculated.The robot positioning method based on the support and positioning mechanism can effectively locate the robot inside a spherical tank.Experiments verified the support performance and robot positioning accuracy of the mechanism.This research proposes an auxiliary support and positioning mechanism for a detection robot inside a spherical tank,which can effectively improve the positioning accuracy of the robot and meet the robotic inspection requirements.

Non-Invasive Positive Pressure Ventilation (NIPPV) in the Pregnant Patient: A Case Series

Rationale: Acute respiratory failure is an uncommon complication of pregnancy. However, it is the most frequent organ dysfunction associated with obstetric admissions to an intensive care unit. The obstetric population is a different group due to its physiology and the presence of the fetus that lacks evidence in the literature within the subject of ventilatory support. Noninvasive positive pressure ventilation (NIPPV) is often avoided due to the lack of knowledge on the safety and efficacy of this modality. Currently, there are no guidelines for the management of respiratory failure in pregnancy. Objectives: To provide evidence in support of the use of NIPPV as a safe and reasonable modality for pregnant patients with respiratory failure. Methods: We retrospectively reviewed medical records of 29 pregnant patients of the Obstetric Critical Care Unit of a tertiary hospital in Panamá City who received NIPPV from 2013 to 2015. Failure to response was defined as the lack of increase in the paO2/FiO2 ratio or clinical deterioration 6 hours after initiating NIPPV. Demographics, indication for NIPPV, duration of treatment, as well as maternal and fetal outcomes were collected. Measurements and Main Results: Mean age was 28.4 ± 6 years, mean body mass index 27.4 ± 3.3, and mean gestational age at admission was 305/7 ± 5 weeks. Twenty-four patients (82.8%) met the criteria for acute lung injury (ALI) and an additional two (6.9%) for acute respiratory distress syndrome (ARDS). The mean duration of ventilation was 50.6 ± 17.27 hours. Statistically significant differences were noted between the paO2/FiO2 ratios in failure and successful patients within 2 hours of NIPPV therapy (P = 0.007) and paO2/FiO2 ratio within 6 hours of NIPPV therapy (P = 0.03). Success was defined when the patient was administered NIPPV, resulting in an improvement (increase in pa/FiO2 ratio) of her ventilatory parameters. Three patients (10.3%) failed to respond to NIPPV and needed to be converted to invasive mechanical ventilation. Patients who required intubation had a longer duration of ICU stay (P = 0.006) and overall hospital stay (P = 0.03). None of patients presented aspiration during NIPPV therapy. Conclusion: The current series is the largest report of pregnant patients requiring ventilatory support who received NIPPV as first line of therapy. This report shows the usefulness of this ventilation modality, avoiding intubation with its risks, of a significant number of patients, especially ventilator-associated pneumonia.

Optimization Method of Bearing Support Positions in a High-Speed Flexible Rotor System

Bearing support position is one of main factors affecting vibration characteristics of rotor systems. To optimize the bearing support positions in a high-speed flexible rotor system (HSFRS) based on the vibration characteristics, an optimization method of bearing support positions in the HSFRS is proposed. In this method, a finite element (FE) model of a high-speed flexible rotor (HSFR) was established. The natural frequencies and mode shapes of the HSFRS were used to obtain the initial design scheme of the bearing support positions. A frequency characteristic equation of the HSFRS was established to obtain the critical speeds of the HSFRS. And a dynamic model of the HSFRS was established to analyze the vibration characteristics for different bearing support position cases. The problem of optimizing bearing support positions in the HSFRS was solved by the developed method. The results showed that vibration amplitudes of the HSFRS were more stable when the bearing support positions were optimized. This study can provide a new method for optimizing bearing support positions of rotor systems.

Promoting Post-Traumatic Growth in Colorectal Cancer Patients:Exploring the Role of Social Support through a Chain Mediation Model

Colorectal cancer(CRC)poses significant physical and psychological challenges that necessitate an exploration of factors influencing post-traumatic growth(PTG)for patient well-being.This study aims to investigate the effects of positive psychological capital(PsyCap)and perceived stress on mediating the social support-PTG relation among 673 CRC patients.Social support,positive PsyCap,perceived stress,and PTG were assessed through questionnaires.The results indicated a direct prediction effect of social support on PTG(LICI=0.481,ULCI=0.644),with the direct effect being 59.5%.Both positive PsyCap and perceived stress exerted a mediating role in the correlation between social support and PTG,with the mediating effects occupying 29.4%(LICI=0.217,ULCI=0.343)and 5.7%(LICI=0.030,ULCI=0.082),respectively.Positive PsyCap further had a chain mediating effect on perceived stress(LICI=0.031,ULCI=0.074),with the chain effect accounting for 5.4%.The total impact of social support on PTG was 100%(LICI=0.882,ULCI=1.008).This model underscores the pivotal role of social support in promoting PTG in CRC patients.Positive PsyCap serves as a crucial mediator in the social support-PTG link,with perceived stress playing a sequential mediating role.Thesefindings suggest that strengthening social support networks and cultivating positive PsyCap may reduce perceived stress and promote the development of PTG in CRC patients.Consequently,intervention programs are recommended to improve the psychosocial well-being of CRC patients.

Research on the Coordinated Control of the Multi-point Array Support Force of Complex Structural Parts

Multi-point array flexible tooling based on multilateration is widely used in the processing and manufacturing of complex curved surface parts. However, during the positioning of workpieces, the force exerted on each flexible support point is not uniform, and there exists force coupling between the support units. In response to the force coupling problem in the multi-point array positioning support process, a coordinated control method for the support force of multi-point array positioning combining correlation coefficient and regression analysis was proposed in this paper. The Spearman correlation coefficient was adopted in this method to study the force coupling correlation between positioning points, and a mathematical model of force coupling was established between positioning units through regression analysis, which can quickly and accurately perform coordinated control of the multilateration support system, and effectively improve the force interference of the multi-point array positioning support scene.

Teachers’ Perceptions of the Challenges and Strategies in Supporting Students with Reading Difficulties

The purpose of this study is to determine the teacher’s perceptions of the challenges and strategies in supporting students with reading difficulties.This study used qualitative method of research and descriptive approach as its research design,in addition to a set of structured interview questions administered through Google Forms to gather data from elementary teachers of Taal Central School,located at Taal Batangas.These structured interview questions were carefully designed to cover various dimensions of the study,including the types of challenges perceived by teachers,strategies employed,and possible solutions for addressing the problems encountered in the process of supporting students with reading difficulties.The results revealed that teachers faced several challenges when teaching students with reading difficulties such as emotional and motivational issues/factors,lack of resources or teaching aids,deficits in knowledge and skills,and problems with student engagement and participation.This study also showed common approaches utilized by the teachers in supporting students with reading difficulties,which were fostering a positive and supportive environment,adopting individualized and multifaceted approaches,and utilizing effective teaching tools and strategies.Lastly,teachers also concluded varied solutions in addressing the challenges perceived in teaching students with reading difficulties towards fostering reading proficiency.These include developing peer support,use of positive reinforcement,and parental involvement.Moreover,specialized resources,professional development for teachers,and specific teaching strategies are also highlighted as crucial components.By integrating these approaches,teachers concluded that it can create a supportive and effective learning environment tailored to the needs of students with reading difficulties.

基于激光-位置传感器的简支梁桥挠度测量方法研究

挠度变形监测是桥梁健康监测的重要组成部分,该文提出了一种基于激光-位置传感器(position sensitive detectors,PSD)的简支梁桥高精度挠度测量系统。该系统采用激光反射偏转位移放大简支梁桥挠度,实现微米级精度的桥梁挠度静、动态监测。介绍了该系统的组成及工作原理,通过激光反射偏转原理可以将桥梁跨中挠度放大7倍以上,实现高精度挠度测量;通过理论推导与误差分析,讨论了激光发射接收器与反射器放置位置对挠度放大倍率的影响;通过试验验证了该体系的测量效果。该体系可在毫米级量程内,准确测量高于1μm的简支梁桥跨中挠度,并且可以对挠度进行动态测量,识别桥梁的自振周期等动力参数。该文提出的激光-PSD测量体系具有精度高、响应速度快、价格低、易于开展长期动态监测的特点。以期为中小跨径简支梁桥的挠度健康监测提供参考。

手术室护士心理灵活性现状及影响因素分析

目的探究手术室护士心理灵活性现状并分析其影响因素,为护理管理者制订针对性干预措施提供借鉴。方法采用便利抽样法,2023年11月至2024年4月选取贵州省13所三级公立医院的403名手术室护士作为调查对象,采用一般资料调查表、多维心理灵活性量表简版、社会支持评定量表、情绪调节问卷进行调查。结果手术室护士心理灵活性得分为(49.67±9.96)分。心理灵活性与社会支持(r=0.392,P<0.05)、认知重评呈正相关(r=0.594,P<0.05),与表达抑制呈负相关(r=-0.206,P<0.05)。性别、文化程度、是否喜欢手术室护理工作在分层回归分析的3个模型中存在统计学意义(均P<0.05)。在控制一般资料变量后,路径分析结果显示社会支持不仅对心理灵活性产生直接影响,还能通过认知重评对心理灵活性产生间接影响(均P<0.05)。结论手术室护士心理灵活性处于中等水平,有待进一步提高。护理管理者应特别关注社会支持、情绪调节对护士心理灵活性的重要影响,采取针对性干预措施提高护士的心理灵活性。

正负压序贯冲吸装置的设计与应用

目的:设计正负压序贯冲吸装置,并测试其在疏通鼻肠管堵管中的应用效果。方法:该装置主要包括正压冲洗部分、负压吸引部分、三通转接头和精准疏通器。正压冲洗部分包括正压冲洗装置、正压压力调节器、压力传感器、加压软袋等;负压抽吸部分包括负压吸引装置、负压压力调节器、负压表、负压瓶等。正压冲洗部分中的加压软袋为中空圆柱形,内层材料为普通聚氯乙烯,外层材料为丙烯腈-苯乙烯-丁二烯共聚物。选取发生鼻肠管堵管的60例患者,随机将其分为对照组和观察组各30例,对照组采用10 mL注射器,观察组采用正负压序贯冲吸装置,均予38~40℃温水疏通,比较2组的疏通效果、堵管疏通所需时间、营养支持天数及费用。采用SPSS 22.0软件对数据进行统计学分析。结果:观察组疏通总有效率(93.3%)高于对照组(73.4%),疏通效果优于对照组,鼻肠管堵管疏通时间、营养支持天数及费用[(7.63±4.97)min、(10.07±3.07)d、(3 180±260)元]少于对照组[(10.73±4.57)min、(13.03±4.05)d、(4 550±660)元],差异有统计学意义(P均<0.05)。结论:正负压序贯冲吸装置可以有效提升鼻肠管堵管疏通效果、缩短堵管疏通所需时间、减少营养支持天数及费用,具有一定实用价值。

气力输送技术在球形氯化镁载体生产过程中的应用研究

球形氯化镁载体是制备球形聚烯烃催化剂的重要粉体原料,其运输与投料以往采用包装桶充氮气封装、小批量转移,操作过程密闭化和连续化水平需提升。经过对球形载体粉体性质的检测,以及用气力输送器和粉体输送泵对球形载体的流化特性进行研究,制定了正压气力输送的技术路线。研究表明当输送距离为垂直方向6m、水平方向1m,以20L发送罐试验机进行模拟试验,平均表观气速为1.7m/s,输送压力差为0.15MPa时,球形载体输送的固气比能达到180kg/m^(3);以500L发送罐试验机进行工业侧线试验,通过设备优化和输送参数调整,固气比可以提高至200kg/m^(3),且输送后球形载体形态仍维持圆润的颗粒形态,制备的聚烯烃催化剂性能优良。经过近一年的工业化应用,采用气力输送后,球形氯化镁载体出料和筛分包装环节的操作效率显著提升,操作环节密闭化和自动化程度明显增强,人工操作强度降低相比原工艺,效率提升了8.5倍。

深水泥岩条件下双壁钢围堰下沉就位施工技术

宁洛高速改扩建工程淮河特大桥22#墩围堰累计入水下沉34 m,嵌入河床19 m,且刃角位于泥岩地质中,在施工过程中受地质、汛期等多方面影响,围堰基坑开挖、下沉精准就位难度很大且工期紧张。设计了新型砼滚杠式限位导向,解决围堰下沉过程中的平面偏位控制难题;采用在吸泥管底部加装液压铰刀和搭设平台采取旋挖钻机钻挖取土的方法,攻克了圆砾土层和全风化泥岩层的水下开挖难题;合理调整内支撑安装顺序,优化安装工艺,极大的提高了施工效率。确保了22#墩围堰在预定工期内下沉到位并成功封底,为大挖深双壁钢围堰的基坑开挖、下沉就位施工提供了经验借鉴。

Using position specific scoring matrix and auto covariance to predict protein subnuclear localization

The knowledge of subnuclear localization in eukaryotic cells is indispensable for under-standing the biological function of nucleus, genome regulation and drug discovery. In this study, a new feature representation was pro-posed by combining position specific scoring matrix (PSSM) and auto covariance (AC). The AC variables describe the neighboring effect between two amino acids, so that they incorpo-rate the sequence-order information;PSSM de-scribes the information of biological evolution of proteins. Based on this new descriptor, a support vector machine (SVM) classifier was built to predict subnuclear localization. To evaluate the power of our predictor, the benchmark dataset that contains 714 proteins localized in nine subnuclear compartments was utilized. The total jackknife cross validation ac-curacy of our method is 76.5%, that is higher than those of the Nuc-PLoc (67.4%), the OET- KNN (55.6%), AAC based SVM (48.9%) and ProtLoc (36.6%). The prediction software used in this article and the details of the SVM parameters are freely available at http://chemlab.scu.edu.cn/ predict_SubNL/index.htm and the dataset used in our study is from Shen and Chou’s work by downloading at http://chou.med.harvard.edu/ bioinf/Nuc-PLoc/Data.htm.

Nonlinear correction of photoelectric displacement sensor based on least square support vector machine

A model of correcting the nonlinear error of photoelectric displacement sensor was established based on the least square support vector machine.The parameters of the correcting nonlinear model,such as penalty factor and kernel parameter,were optimized by chaos genetic algorithm.And the nonlinear correction of photoelectric displacement sensor based on least square support vector machine was applied.The application results reveal that error of photoelectric displacement sensor is less than 1.5%,which is rather satisfactory for nonlinear correction of photoelectric displacement sensor.

Support Vector Machine Assisted GPS Navigation in Limited Satellite Visibility

This paper investigates performance improvement via the incorporation of the support vector machine(SVM)into the vector tracking loop(VTL)for the Global Positioning System(GPS)in limited satellite visibility.Unlike the traditional scalar tracking loop(STL),the tracking and navigation modules in the VTL are not independent anymore since the user’s position can be determined by using the information from other satellites and can be predicted on the basis of the states of the user.The method proposed in this paper makes use of the SVM to bridge the GPS signal and prevent the error growth due to signal outage.Similar to the neural network,the SVM is motivated by its ability to approximate an unknown nonlinear input-output mapping through supervised training.The SVM is employed for predicting adequate numerical control oscillator(NCO)inputs,i.e.,providing better prediction of residuals for the Doppler frequency and code phase in order to maintain regular operation of the navigation system.When the navigation processing is in good condition,the SVM is at the training stage,and the output information from the discriminator and navigation filter is adopted as the inputs.Other machine learning(ML)algorithms such as the radial basis function neural network(RBFNN)and the Adaptive Network-Based Fuzzy Inference System(ANFIS)are employed for comparison.Performance evaluation for the SVM assisted architecture as compared to the RBFNNand ANFIS-assisted methods and the un-assisted VTL will be carried out and the performance evaluation during GPS signal outage will be presented.The proposed design is very useful for navigation during the environment of limited satellite visibility to effectively overcome the problem in the environment of GPS outage.