3~6岁幼儿粗大动作能力发展现状研究

目的:探析3~6岁幼儿粗大动作能力和各子能力发展水平的现状,为3~6岁幼儿粗大动作能力发展评估监测与精准实施运动干预提供理论依据和数据支撑。方法:选取151名3~4岁幼儿、169名4~5岁幼儿、186名5~6岁幼儿共506名3~6岁健康幼儿,采用粗大动作发展测试(TGMD-3)对测试者进行测试,评估幼儿粗大动作发展水平,比较不同年龄段幼儿粗大动作能力发展水平特点,对其总体发展水平和各子能力发展水平进行比较与分析。结果:3~4岁、4~5岁、5~6岁幼儿粗大动作能力测试得分分别为(40.36±1.92)分、(9.28±0.95)分、(62.88±1.20)分,幼儿3个年龄段间粗大动作能力指标,以及移动性动作技能指标、操作性动作技能指标等各子能力指标均出现显著性差异(P<0.01)。结论:(1)幼儿的粗大动作能力发展受年龄特征影响明显,3~4岁幼儿的粗大动作技能发展最不成熟,且不稳定,个体间差异较大;4~5岁幼儿的粗大动作技能发展较为稳定,且较为平衡;5~6岁幼儿的粗大动作技能发展最佳,且较为稳定。(2)在3~6岁年龄段中幼儿移动性动作技能平稳增长,在5~6岁年龄段幼儿操作性动作技能处于发展的敏感期。

黄河流域水资源税改革的成效、问题与完善

水资源税改革是国家为了提高水资源利用效率,实施国家节水行动,建立水资源刚性约束的制度保障。水资源税改革试点先后在河北等10个省区开展,其中7个省区在黄河流域。目前,黄河流域水资源税改革试点取得了一定成效,但也存在一些问题,如水价调整实行难度较大、供水企业税收负担增加、特种行业的范围难以界定、疏干排水税额设计有待优化、税收优惠政策仍需完善、收入分配机制不够健全等。为深化黄河流域水资源税改革,应从完善水价调整机制、降低用水企业负担、调整特种行业范围、提高疏干排水税额标准、完善税收优惠政策、健全水资源税收入分配机制等方面着手,优化黄河流域水资源配置,统筹“流域—区域”的管理模式,推进黄河流域生态保护和高质量发展。

铝合金拉伸塑性变形的非线性电磁超声检测

针对金属构件早期塑性损伤检测的难点问题,建立非线性电磁超声表面波弹塑性模型,通过改变材料内部塑性应变大小模拟不同程度的塑性损伤,研究应力应变、塑性损伤、超声非线性系数三者之间的关系,并利用非线性电磁超声实验方法,对拉伸变形的试件进行塑性损伤评估。搭建了非线性电磁超声表面波检测系统,对导入不同塑性变形的试件进行相对非线性系数的检测。实验结果表明,在材料屈服硬化阶段早期(ε≤5%),随着被测试件中导入塑性应变量的增加,相对非线性系数迅速增大;在材料屈服硬化阶段后期(5%<ε≤7%),随塑性损伤程度的增加,相对非线性系数增幅逐渐趋于平缓;在材料出现颈缩时(ε>7%),材料内部应力的降低导致相对非线性系数出现明显下降。据此,可以对塑性损伤的变化情况进行有效监测,并进一步评估材料的力学寿命。

无管胸腔镜在肺大疱切除术中的应用效果

目的评价无管胸腔镜进行肺大疱切除的优势和安全性。方法选取2017年7月至2021年4月清华大学第一附属医院51例因气胸拟行肺大疱切除的患者为研究对象,按照患者意愿将其分为无管胸腔镜组和气管插管胸腔镜组。无管胸腔镜组20例,行无管胸腔镜手术;气管插管胸腔镜组31例,行常规气管插管胸腔镜手术。记录并比较两组麻醉时间、手术时间、术中最低脉搏氧饱和度、术中失血量、术后手术室滞留时间、引流管保留时间、术后追加止痛药情况、术后住院时间、术后1个月内咳嗽或咽部不适发生情况、术后6个月内气胸复发情况。结果无管胸腔镜组麻醉时间、术后手术室滞留时间均短于气管插管胸腔镜组,术中最低脉搏氧饱和度、术后1个月内咳嗽或咽部不适发生率均低于气管插管胸腔镜组,差异有统计学意义(P<0.05)。两组引流管保留时间、术后追加止痛药、术后住院时间、术后6个月内气胸复发率比较,差异无统计学意义(P>0.05)。结论无管胸腔镜切除肺大疱可以缩短麻醉时间,降低术后咳嗽、咽部不适等并发症,安全性可靠,值得进一步推广。

山区河流型水库碎土石滑坡涌浪三维数值模拟研究

采用RNGκ-ε紊流模型与VOF方法对散粒体滑坡涌浪进行数值模拟。通过与已有文献的试验结果对比分析,发现数值模拟得到的滑坡体水下初始堆积形态与试验结果吻合较好,且波幅计算精度较高。基于此,建立了某山区河流型水电工程库区的三维模型,模拟了碎土石滑坡涌浪在库区内的生成与传播过程,并分析了涌浪的波幅和波速特征。研究结果表明,通过数值模拟获得的涌浪波幅和传播速度等参数,可以为大坝安全评估和滑坡涌浪灾害影响范围预测提供一定的科学依据,还可为通航河流航行船舶的避险范围提供参考。

2-14 Production of New Nuclides 216U and 215U

The study on the decay properties of new isotopes located far from the beta stability line is current the focus of nuclear physics. For isotopes in the region Z >82 and N <126, -emission prevails as radioactive decay mode and -spectroscopy is the most important tool to obtain information on the nuclear structure. In the heavy nuclei region with N=124 and 126 isotones, an intruder state (h9=2.f7=2)8+ based on the attractive interaction of f7=2 protons and f5=2 neutrons has been significantly observed, which increases the binding energy of this configuration with increasing proton number.

5-22 Design and Optimization of a Multi-re Time-of-flight Mass Analyzer for LPT

Multi-reflection time-of-flight mass spectrometer (MR-TOF-MS) is one of the new experimental devices developed in recent years. As the flight path extended several orders of magnitude as the analyzer is traversed many times by the ions, it allows achieving higher mass resolving power than the conventional time-of-flight mass spectrometry.

2-21 Attempt to Study the a-decay of 216U by 40Ca+natHf Reaction

An attempt has been made recently to synthesize very neutron-decient 216U isotope in 40Ca+natHf reaction atthe gas-lled recoil separator SHANS[1]. A beam of 40Ca12+ at an energy of Elab=194.6 MeV was delivered by thesector focusing cyclotron of the Heavy Ion Research Facility in Lanzhou (HIRFL). The average beam intensity wasabout 100 pnA. Self-support targets of natural hafnium foils with thickness of 420 g/cm2 was mounted in a edframe. Evaporation residues recoiled from the target were separated from the primary beam by the separator andthen implanted into the Si-box detector (consist of three position sensitive silicon detectors and eight non-positionsensitive silicon detectors)[2]. In order to distinguish the -decay events from the implantation events, two multi-wire proportional counters (MWPCs) were mounted upstream from the Si-box detector. Behind the Si-box detectora fourfold segmented Clover detector was installed for -ray studies.

α Decay of the New Isotope ^(204)Ac

Proton-andα-decay spectroscopy can provide valuable information on the nuclear structure and masses of neutron-de cient isotopes.In 1994,the proton drip line of Ac was reached by the detection of^(207)Ac which was identified via the-decay spectroscopy.Four years later,the neighboring proton-unbound nucleus ^(206)Ac was discov-ered.

New Isotope^(207)Th and Odd-Even Staggering in-Decay Energies for Nuclei with Z>82 and N<126

The new thorium isotope ^(207)Th has been produced in the 5n evaporation channel of the fusion reaction ^(36)Ar+^(176)Hf.The 197-199 MeV ^(36)Ar^(11+)beam with a typical intensity of0.4 pμA was delivered by the Sector Focusing Cyclotron of the Heavy Ion Research Facility in Lanzhou(HIRFL),China.

New Short-lived Neutron-de cient Isotope ^(220)Np

Alpha decay,as a pervasive decay mode of unstable heavy nuclei,plays a crucial role in the identification of new superheavy elements and investigation on nuclear structure of exotic nuclei near the proton drip line.

A Stop-timing Microchannel Plate Detector for Multi-reflection Time-of-fight Mass Analyzer

Precision mass measurements of exotic nuclei at the limits of stability provide deeper insight into the nature of the nuclear interaction[1],and thus access to verification of nuclear models.

Preliminary Test of Multi-reflection Time-of-flight Mass Analyzer Operating in In-trap-lift Mode

The multi-reflection time-of-flight mass analyzer for researches of short lived nuclei has been designed and constructed and is being test now.The design and previous optimization procedures have been reported in Refs.[1-3].After these,more advanced optimization work has been done for the in-trap-lift mode.Different from the trends in Fig.2 of Ref.[3],Rmax increases steadily while increasing the number of revolutions,and it reaches 1.6105 at 300 laps,corresponding a time-of-flight(TOF)of 6.4 ms for the ion species of 40Ar1+.It seems that the beam size smaller than 3 mm diameter influences little on Rmax when“real”optimal parameter sets are found.

Monte-Carlo Simulation of Ion Distributions in a Gas Cell for Multinucleon Transfer Reaction Products at LENSHIAF Spectrometer

The multinucleon transfer(MNT)reaction is one promising way to produce neutron-rich and attracts more and more attentions theoretically and experimentally.In the ongoing big project HIAF(High Intensity heavy-ion Accelerator Facility),a Low Energy Nuclear Structure spectrometer called LENSHIAF specific to MNT reactions will be designed and constructed.In this spectrometer,the researches will be concentrated on the synthesis and identification of new neutron-rich nuclei,and on the study of their nuclear structure and decay properties.The conceptual design has been reported in Refs.[1,2].The most challenge part is how to collect and stop efficiently the high-energy products from the MNT reactions into the gas cell.

Production of Very Neutron-deficient Actinide Nuclei using the ^(36)Ar and ^(40)Ar Beams

In order to systematically investigate the-decay properties of U-isotopes near the N=126 shell and study the fine structures of 218Pa and 211−213Th,enriched targets,180W,182Wand 176Hf,were bombarded by the 36Ar and 40Ar beams provided the Heavy Ion Research Facility in Lanzhou(HIRFL).Combinations of beam and target as well as the beam energy,beam intensity,target thickness,irradiation time were listed in Table 1.Fusion-evaporation residues(ERs)were recoiled from the targets and separated from the primary beams using the gas filled recoil separator,SHANS[1].After passing through a multi-wire proportional chamber,the ERs were implanted into a Si-box detector[2]amounted at the focal plane of SHANS.Gamma rays emitted from the ERs were detected by three Ge detectors attached to the Si-box.All-decay and gamma-ray signals were registered and proceeded by a digital data acquisition system.

Low Energy Nuclear Structure Spectrometer for Multi-nucleon Transfer Reactions at HIAF

Many nuclear theories have predicted the island of stability located around proton number of 114,120 or 126 and neutron number of 184 or 172.The synthesis of nuclei on the island of stability and the study of their exotic decay properties are crucial for the understanding of nuclear structure and properties under extremely strong Coulomb fields,and the discovery of maximum nuclear magic numbers.There is no appropriate method to produce such neutron-rich nuclei except multi-nucleon transfer(MNT)reaction.The target-like fragments(TLF)emit into a wide angular range with a broad energy distribution,which makes it very difficult to collect,separate and identify the nuclei of interest.

Optimization of Multi-reection Time-of-ight Mass Analyzer Operating in In-trap-lift Mode

The multi-reflection time-of-flight mass spectrometer(MRTOF-MS)has been developed as a new device in recent years.Up to now,many MRTOF-MSs for mass measurements and isobaric separations have been commissioned or under construction.Injection and ejection of ions into/from MRTOF-MS have been achieved by switching the electric potentials of the electrodes to appropriate values while the ions are passing.Thus,According to the switching mode,all MRTOF-MSs can be cataloged into two types:mirror-switching and in-trap-lift mode.

An MRTOF-MS at SHANS

A multi-re ection time-of-ight mass spectrometer(MRTOF-MS)at the spectrometer for heavy atom and nuclear structure(SHANS)[1],which will be used for direct atomic mass measurement and nuclear spectroscopy,is under construction.