基于离体测量估计长白落叶松原位最大净光合速率的方法

以黑龙江省帽儿山林场15年生长白落叶松人工林为研究对象,通过对针叶进行原位及离体测量获取其原位最大净光合速率(SP_(n max))及离体最大净光合速率(AP_(n max)),分析AP_(n max)随离体时间(t_a)的变化规律,建立SP_(n max)与AP_(n max)和t_a的函数关系,并分析了林木大小及环境因子对AP_(n max)下降过程的影响,构建了长白落叶松SP_(n max)预估模型.结果表明:在不恢复水分供应的条件下,针叶AP_(n max)随t_a的增加而降低,且水汽压亏缺(VPD)和叶片温度(T_(leaf))越高,AP_(n max)的下降速度越快、幅度越大.以VPD和t_a为自变量的线性预估模型对SP_(n max)的拟合效果最好(Ra^2为0.774,RMSE为20.73),模型的预估精度随着t_a的增加而降低,t_a超过20min后,模型预估精度稳定在97%左右.本文采用离体测量方法通过建立回归模型估计长白落叶松的SP_(n max),不仅具有较好的预估能力和相对稳定的估计精度,同时大大提高了SP_(n max)的测定效率,具有较高的应用价值.

裸鼠乳腺肿瘤生长过程中电特性的在体测量实验研究

利用电特性(electric properties,EPs;电导率和介电常数)作为特征值对生物组织进行区分(例如:正常组织vs.肿瘤组织)可以应用于疾病尤其是肿瘤的早期诊断。生物组织的电特性与组织生理病理状态有密切的联系,在生物组织离体后其电特性发生明显变化,因此,在体测量的组织电特性数据更加真实,对疾病诊断有重要意义。本研究采用自制的小尺寸探头,对种植1~4周(10只/周)人类乳腺癌(MDA MB 231)的BALB/c裸鼠模型的肿瘤组织及正常组织的EPs进行在体和离体测量,测量频率范围为0.5~5 MHz,并对肿瘤组织进行病理学检测。对肿瘤组织及正常组织EPs数据进行分析得到裸鼠乳腺癌组织与正常组织的电导率和介电常数存在显著差异(P<0.01)。同一组织在体测量及离体测量数据存在显著差异(P<0.01)。对1~4周的乳腺癌肿瘤组织电特性数据分析得到在肿瘤发展过程中,其EPs产生变化。本研究结果表明小尺寸探头测量的在体生物组织EPs与离体EPs有明显差异,在体测量生物组织的EPs对根据EPs变化诊断早期癌症有重要意义。

9.5~10.5 GHz频段室内离体信道的测量与建模

为探索高频段室内离体信道的无线传播特性,对9.5~10.5 GHz频段多个典型室内场景进行离体信道测量。在大尺度衰落方面,通过研究路径损耗发现人体遮挡因子与旋转角度呈正弦函数关系,并与收发端距离呈现负指数关系,因此建立距离与角度联合相关的新型路径损耗模型,并根据阴影衰落统计特性证明新模型的精确性与适用性。在小尺度衰落方面,通过分析路径损耗与均方根(RMS,root mean square)时延扩展的线性相关性,获得距离与角度相关的新型RMS时延扩展模型。证明了收发端距离与人体旋转产生的遮挡因子越大,路径损耗和多径衰落也越严重。新型离体信道模型可用于设计物联网环境体域网(BAN,body area network)的离体链路,为未来的室内无线通信系统提供理论与实践基础。

静脉顺应性的影响因素及其测量方法

静脉顺应性是反映静脉对内压力的应变性的重要指标 ,其测量方法分为在体与离体两类 ,前者又分无创性与有创性两种。被测对象的年龄、静脉的解剖结构、组织学状况、血管压力与轴向伸长率、重力环境等诸多因素均影响着静脉顺应性。

人体血管壁超声传输衰减特性的研究

本文利用超声脉冲反射法,对人体血管壁声衰减特性进行了离体测量,给出了人体血管壁声能量衰减参数的测量值。这对超声在医学领域的应用以及超声连体非介入血栓消溶有着十分重要的意义。

脊柱运动测量方法研究的进展

脊柱运动测量方法研究的进展朱青安，钟世镇综述徐达传，审校脊柱节段间的相对运动与脊柱外科有密切联系。脊柱各种损伤对脊柱运动稳定性的影响，脊柱矫形术式和内固定器疗效评价都涉及到对脊柱运动的了解。用什么量来描述并测量脊柱的运动是脊柱生物力学所关注的问题。目...

剪切波弹性成像诊断大鼠非酒精性脂肪肝病的实验研究

目的探讨剪切波弹性成像(SWE)诊断大鼠非酒精性脂肪肝病(NAFLD)的价值。方法将52只雄性SD大鼠随机分为实验组40只和对照组12只,其中实验组喂养蛋氨酸和胆碱缺乏饲料建立NAFLD模型,对照组正常喂养,分别于实验1周、2周、3周和4周后随机抽取实验组10只、对照组3只大鼠,均于麻醉状态下及处死即刻行SWE检测肝脏硬度(LSM)及标准差(SD);然后解剖大鼠,获得离体状态下LSM及SD。对切除的肝脏组织进行病理学检查判断有无脂肪变性。绘制受试者工作特征(ROC)曲线分析SWE诊断大鼠NAFLD的效能。结果根据病理学检查结果,将大鼠分为非脂肪变性组17只,脂肪变性组35只。脂肪变性组处死即刻和离体状态下LSM分别为(3.95±1.78)kPa、(1.53±0.32)kPa,均高于非脂肪变性组[(2.91±1.53)kPa、(1.23±0.16)kPa],差异均有统计学意义(均P<0.05);两组麻醉状态下LSM比较差异无统计学意义。非脂肪变性组、脂肪变性组麻醉状态下SD分别为(1.70±0.56)kPa、(1.86±1.21)kPa,均高于处死即刻SD[(0.92±0.65)kPa、(1.08±0.73)kPa]和离体状态下SD[(0.26±0.16)kPa、(0.33±0.16)kPa],差异均有统计学意义(均P<0.05)。ROC曲线分析显示,处死即刻和离体状态下LSM诊断大鼠NAFLD的曲线下面积分别为0.69、0.86,灵敏度和特异度分别为60.0%、60.0%和82.4%、100%。结论应用SWE诊断大鼠NAFLD具有较好的价值,NAFLD大鼠不同状态下LSM均明显升高。

近红外光谱无创血糖检测技术的研究

对现有的一些使用近红外光谱无创离体和在体测量葡萄糖的研究结论,结合我们的研究结果进行评述。首先介绍建立葡萄糖光谱检测的基本理论。在光谱检测的分析研究中,离体测量表现出良好的结果;在体葡萄糖检测和预测,结果精度较差,离临床和家庭使用还有一些距离。

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S^1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.

Synthesis and Conductivity of Oxyapatite Ionic Conductor La10-xVx（SiO4）6O3＋x

Apatite-lanthanum silicate has attracted considerable interest in recent years due to its high oxide ion conductivity.In this paper,V-doped samples La10-xVx(SiO4) 6O3+x(0≤x≤1.5) were prepared by sol-gel method and the influences of V-dopant content on calcining temperature and conductivity were reported.The samples were characterized by thermal analysis(TG-DSC) ,X-ray diffraction(XRD) and scanning electron micrograph(SEM) . The apatite was obtained at 800°C,a relatively low temperature in comparison to 1500°C with the conventional solid-state method.The ceramic pellets sintered at 1200°C for 5 h showed a higher relative density than La9.33Si6O26 pellets sintered at 1400°C for 20 h.The conductivities of samples were measured by electrochemical impedance spectroscopy.The conductivity was improved with the increase of V-dopant content on La site.

Unbiased Estimation Formula of Unit Weight Standard Deviation in Regularization Solution

Regularization method is an effective method for solving ill\|posed equation. In this paper the unbiased estimation formula of unit weight standard deviation in the regularization solution is derived and the formula is verified with numerical case of 1 000 sample data by use of the typical ill\|posed equation, i.e. the Fredholm integration equation of the first kind.

Measurement of thermal conductivity,viscosity and density of ionic liquid [EMIM][DEP]-based nanofluids

This article studied experimentally the effect of multi-wall carbon nanotubes （MWCNTs） on the thermo physical properties of ionic liquid-based nanofluids. The nanofluids were composed of ionic liquid, 1-ethyl-3- methylimidazolium diethylphosphate [EMIM][DEP], or its aqueous solution[EMIM][DEP]（1） ＋ H20（2） and MWCNTs without any surfactants. The thermal conductivity, viscosity and density of the nanofluids were mea- sured experimentally. The effects of the mass fraction of MWCNTs, temperature and the mole fraction of water on the thermo physical properties of nanofluids were studied. Results show that the thermal conductivity of nanofluids increases within the range of 1.3%-9.7% compared to their base liquids, and have a well linear depen- dence on temperature. The viscosity and density of the nanofluids exhibit a remarkable increase compared with those of the base liquids. Finally, the correlation of the effective thermal conductivity and viscosity of the nanofluids was made using the models in the literatures.

Spatial Object Aggregation Based on Data Structure, Local Triangulation and Hierarchical Analyzing Method

This paper focuses on the methods and process of spatial aggregation based on semantic and geometric characteristics of spatial objects and relations among the objects with the help of spatial data structure (Formal Data Structure),the Local Constrained Delaunay Triangulations and semantic hierarchy.The adjacent relation among connected objects and unconnected objects has been studied through constrained triangle as elementary processing unit in aggregation operation.The hierarchical semantic analytical matrix is given for analyzing the similarity between objects types and between objects.Several different cases of aggregation have been presented in this paper.

Quantum Nondemolition Measurement of the Collective Motional Energy of Two Trapped Ions

We propose a quantum nondemolition measurement of the collective motional energy of two trapped ions for the first time.It is based on the excitation of the two ions by two lasers with appropriate frequencies and amplitudes.The scheme also provides a new possibility of preparing vibrational Fock states and laser cooling.

The States of Thermal Plasma Torch and Its Application

In recent years, plasma technology has emerged as a novel technique for the manufacture of newer and better materials. The thermodynamic state of thermal plasma approaches local thermodynamic equilibrium, temperature of heavy particle is higher （ 10^3 -10^4 K ） and the temperature range of electron is 10^4- 10^6 K. The state of thermal plasma can be described by an unitive thermodynamic temperature. The characteristics of thermal plasmas are high temperature, high enthalpy, high energy density, controllable atmosphere, steep temperature gradient etc. It has been widely applied in field of processing, metallurgy, material, chemical engineering, environmental protection.

Radon Gas Measurements through Geiger and Sodium Iodide Scintillator——Study Efficiency Comparison

With the use ofa Geiger proportional counter with sensor tube of Russian and Chinese origin, a comparison was made in this work between measurements of environmental ionizing radiation with these detectors and a sodium iodide scintillator activated with TI （Thallium NaI）. Through measurements carried out in a room located inside a tower 25 meters high on the ITA （Technological Institute of Aeronautics） campus, it was possible to study the efficiency of the three instruments for the environmental measurement of ionizing radiations at that location. Between March 7th and June 2nd of 2017, in that region, nine intense and weak rains were observed with 12 cold fronts coming from southern Brazil. Radiation measurements and the local meteorology involved are analyzed in this work to verify possible correlations.

Stagnant low-energy ions in the near cusp region observed by Cluster

Measuring the low-energy ions in the Earth's magnetotail lobes is difficult, because a spacecraft becomes positively charged in a sunlit and tenuous plasma environment. Recent studies have introduced a new method, making use of the positive electric potential on the Cluster spacecraft, to measure the low-energy ions(less than a few tens of electronvolts) in the polar caps/magnetotail lobes in the years 2001–2010. With the measured velocities, we are able to study the trajectories of these low-energy ions. Particle tracing has been used in previous studies, confirming that ions of ionospheric origin are the dominant contributor to the ion population in the Earth's magnetotail lobes. In this work, we continue to study the source of low-energy ions measured in the lobes. We found that not all of the low-energy ions in the lobes come directly from the ionosphere. Particle tracing infers that some of the low-energy ions start to move tailward from the cusp/near-cusp region with a zero parallel velocity. In the following, we refer to these low-energy ions as stagnant low-energy ions. On the other hand, the in situ measurements by Cluster show a population of low-energy ions in the cusp/near-cusp region with pitch angles near 90°(i.e., no significant parallel velocity).The locations of stagnant low-energy ions are determined by particle tracing and in situ measurements. Similar ion energies and spatial distributions determined by these two methods confirm the presence of the stagnant low-energy ion population.

Multiple magnetic topologies in flux transfer events: THEMIS measurements

Flux transfer events （FTEs） are local transient magnetic reconnections at the magnetopause （MP） that provide channels for transport of solar wind energy and plasma into the magnetosphere （MSP）. All current theoretical models suggest that FTEs are open-flux ropes; however, global simulations show that they contain both open and closed magnetic fields. To clarify this to- pology, we analyzed 441 events observed by THEMIS and investigated their magnetic topologies. Only one type of open field line was detected in most magnetosheath （MSH） FTEs, independent of the polarity of the Bn bipolar signatures. Newly formed MSH field lines were also observed. In the all MP boundary layers FTEs and most MSP FTEs, multiple types of topologies were observed, irrelevant to the Bn bipolar polarity. Closed field lines were found in all MP boundary layers and MSP FTEs. Meanwhile very few boundary FTEs contained the newly formed MSH flux. In some situations, only closed field lines were seen in MSP FTEs, which are referred to as the fossil FTEs. These results, which largely differ from the traditional view, demonstrate the existence of complex magnetic topologies in FTEs. Based on these results, we propose a new 3D FTE picture to modify the current FTE models.

Temperature of Heavy Fragments in Heavy-Ion Collisions

The heavy fragments in heavy-ion collisions are finally formed after the hot prefragments undergo sequential decay, of whom the temperature should be much lower than that of prefragments. Using the double ratio （DR） method, the isotopic thermometer （Tiso ） for heavy fragment is constructed using the yield of heavy isotopes. Tiso of heavy fragment is obtained by analyzing the measured data in the 1A GeV 124＇136Xe and 140A MeV 48Ca/64Ni reactions. Result shows that Tiso varies from 0.5 MeV to 10 MeV. But most Tiso is around 1 4- 0.5 MeV, which is much lower than temperature of light particles. Result also indicates that the difference between Tiso of heavy fragments in different reactions is very small, and ~o is independent on the size of the reaction system, the incident energy and the neutron-richness of the projectile.