Assessing the dynamics of human activity intensity and its natural and socioeconomic determinants in Qinghai-Tibet Plateau

Investigating the spatiotemporal variation of human activity intensity and its determinants is a crucial basis for further revealing the mechanism of human-environment interaction and optimizing the human development mode.In this study,the human activity intensity on the Qinghai-Tibet Plateau(QTP)from 1990 to 2020 was measured based on the quantitative model of land use data and the actual regional background,and the under-lying natural and socioeconomic determinants were investigated using spatial econometric methods.The results demonstrate that(1)the human activity intensity in QTP has increased by 11.96%,and there are differences in different spatial scales;the areas with high human activity intensity are distributed in the Hehuang Valley where Xining City and its surrounding areas are located,as well as the One-River and Two-River Area where Lhasa City and surrounding areas are located.(2)Human activity intensity has significant positive spatial spillover,suggesting that local changes will cause changes in the same direction in adjacent areas.(3)The human activ-ity intensity in QTP is affected by various determinants.Concerning socioeconomic factors,the economic level has no significant impact on the human activity intensity in QTP,which differs from the general regional law.Both urbanization and traffic conditions have a significant positive effect,and the impact intensity continues to increase.Concerning natural factors,topographic relief has a significant positive effect;the impacts of temper-ature and vegetation coverage have changed from insignificant to a significant positive effect;the impacts of precipitation and river network density have not been verified;there is no linear relationship between altitude and human activity intensity in the entire QTP,while it exists in local regions.Finally,this study proposes three policy implications for the realization of a more harmonious human-environment relationship in QTP.

Fermion Determinant with Dynamical Chiral Symmetry Breaking

One-loop fermion determinant is discussed for the case in which the dynamical chiral symmetry breakingcaused by momentum-dependent fermion self-energy ∑(p2) takes place. The obtained series generalizes the heat kernelexpansion for hard fermion mass.

Carrier Dynamics Determined by Carrier-Phonon Coupling in InGaN/GaN Multiple Quantum Well Blue Light Emitting Diodes

Phonon sidebands in the electrolumiescence(EL) spectra of InGaN/GaN multiple quantum well blue light emitting diodes are investigated. S-shaped injection current dependence of the energy spacing(ES) between the zero-phonon and first-order phonon-assisted luminescence lines is observed in a temperature range of 100–150 K.The S-shape is suppressed with increasing temperature from 100 to 150 K, and vanishes at temperature above200 K. The S-shaped injection dependence of ES at low temperatures could be explained by the three stages of carrier dynamics related to localization states:(i) carrier relaxation from shallow into deep localization states,(ii) band filling of shallow and deep localization states, and(iii) carrier overflow from deep to shallow localization states and to higher energy states. The three stages show strong temperature dependence. It is proposed that the fast change of the carrier lifetime with temperature is responsible for the suppression of S-shaped feature.The proposed mechanisms reveal carrier recombination dynamics in the EL of InGaN/GaN MQWs at various injection current densities and temperatures.

FINITE ELEMENT METHOD COMBINED WITH DYNAMIC PHOTOELASTIC ANALYSIS TO DETERMINE DYNAMIC STRESS-INTENSITY FACTORS

The present paper is addressed to the finite element method combined with dynamic photoelastic analysis of propagating cracks, that is, on the basis of [1] by Chien Wei-zang, finite elements which incorporate the propagating crack-tip singularity intrinsic to two-dimensional elasticity are employed. THe relation between crack opening length and time step obtained from dynamic photoelaslie analysis is used as a definite condition for solving the dynamic equations and simulating the crack propagations as well As an example, the impact response of dynamie-bending-test specimen is investigated and the dynamic stress-intensity factor obtained from the mentioned finite element analysis and dynamic photoelasticity is in reasonable agreement with each other.

GPS dynamic cycle slip detection and correction with baseline constraint

When the cycle slips take place in the attitude determination of a moving platform, the precision of the attitude will be impaired badly. A method of cycle slip detection and correction is proposed, which is suitable to the dynamic measurement using GPS carrier phase： the cycle slips detection is first achieved by triple difference observables, then the cycle slips correction is performed with baseline length constraint. The simulation results show that the proposed method is effective to the dynamic cycle slips problem.

A rapid and accurate direct measurement method of underground coal seam gas content based on dynamic diffusion theory

Coal seam gas content is frequently measured in quantity during underground coal mining operation and coalbed methane(CBM)exploration as a significant basic parameter.Due to the calculation error of lost gas and residual gas in the direct method,the efficiency and accuracy of the current methods are not inadequate to the large area multi-point measurement of coal seam gas content.This paper firstly deduces a simplified theoretical dynamic model for calculating lost gas based on gas dynamic diffusion theory.Secondly,the effects of various factors on gas dynamic diffusion from coal particle are experimentally studied.And sampling procedure of representative coal particle is improved.Thirdly,a new estimation method of residual gas content based on excess adsorption and competitive adsorption theory is proposed.The results showed that the maximum error of calculating the losing gas content by using the new simplified model is only 4%.Considering the influence of particle size on gas diffusion law,the particle size of the collected coal sample is below 0.25 mm,which improves the measurement speed and reflects the safety representativeness of the sample.The determination time of gas content reduced from 36 to 3 h/piece.Moreover,the absolute error is 0.15–0.50 m^3/t,and the relative error is within 5%.A new engineering method for determining the coal seam gas content is developed according to the above research.

Continuous determination of bath carbon content on 150tBOF by off-gas analyzer

The first imported off-gas analysis system on 150 t BOF at Benxi Plates Co.Ltd. is presented and the continuous determination of bath carbon content has been studied. Thecomparison between the whole-course carbon integral model and the end-point carbon prediction modelhas been made. The results show that the regular change of CO, CO_2 and N_2 content in the off-gasduring blowing plays an important role in judging the smelting end-point of converter; the cubiccurve fitting model has a higher hit rate over 95 percent for the heats whose end-point carboncontent is lower than 0.10 percent with a precision of +-0.02 percent and has a large error for theheats whose end-point carbon content is more than 0.15 percent.

Kinematics and Dynamics Analysis of a Quadruped Walking Robot with Parallel Leg Mechanism

It is desired to require a walking robot for the elderly and the disabled to have large capacity,high stiffness,stability,etc.However,the existing walking robots cannot achieve these requirements because of the weight-payload ratio and simple function.Therefore,Improvement of enhancing capacity and functions of the walking robot is an important research issue.According to walking requirements and combining modularization and reconfigurable ideas,a quadruped/biped reconfigurable walking robot with parallel leg mechanism is proposed.The proposed robot can be used for both a biped and a quadruped walking robot.The kinematics and performance analysis of a 3-UPU parallel mechanism which is the basic leg mechanism of a quadruped walking robot are conducted and the structural parameters are optimized.The results show that performance of the walking robot is optimal when the circumradius R,r of the upper and lower platform of leg mechanism are 161.7 mm,57.7 mm,respectively.Based on the optimal results,the kinematics and dynamics of the quadruped walking robot in the static walking mode are derived with the application of parallel mechanism and influence coefficient theory,and the optimal coordination distribution of the dynamic load for the quadruped walking robot with over-determinate inputs is analyzed,which solves dynamic load coupling caused by the branches’ constraint of the robot in the walk process.Besides laying a theoretical foundation for development of the prototype,the kinematics and dynamics studies on the quadruped walking robot also boost the theoretical research of the quadruped walking and the practical applications of parallel mechanism.

HOI延迟对LEO卫星简化动力学POD的影响

通常使用无电离层(IF)线性组合(LC)消除低地球轨道(LEO)卫星简化动力学精密定轨(POD)一阶电离层延迟误差,忽略了高阶电离层(HOI)延迟误差。随着LEO卫星POD技术的发展,计算不同轨道高度的HOI延迟并探索其变化已成为进一步提高POD精度的重要手段。首先,使用国际参考电离层-2016(IRI-2016)和国际地磁参考场第13代(IGRF-13)模型,计算电离层穿刺点(IPP)位置和地磁场强度。其次,使用平滑星载GNSS数据计算电离层斜路径总电子含量(STEC)。然后,分别计算GOCE、GRACE-A和SWARM-A/B卫星的二阶和三阶电离层延迟。最后,评估了HOI延迟对LEO卫星重叠轨道分析、卫星激光测距(SLR)检核和精密科学轨道(PSO)比较结果的影响。实验结果表明:HOI延迟对LEO卫星简化动力学POD的影响大约在毫米至厘米的数量级上;HOI延迟对LEO卫星简化动力学POD外符合精度的影响分别达到0.92,0.22,0.21和0.18 mm;随着LEO卫星轨道高度的增加,HOI延迟对LEO卫星简化动力学POD的影响减小。

违约金调整排除特约的效力认定——兼析《民法典》合同编解释(征求意见稿)第68条

违约金调整排除特约的效力认定问题是长期困扰中国理论界与实务界的难题,解决问题的关键在于探寻私法自治与司法干预的衡平之道。如此可形成一个调和方案,即尊重契约自由,但在不予调整违约金将导致明显不公时借道契约正义,实现司法介入的“矫正”功能。《民法典》合同编解释(征求意见稿)第68条以“显失公平”规则审查特约排除条款,未考虑到《民法典》第151条“乘人之危”的主观要件,仅以满足客观要件“对待给付失衡”即认定排除特约无效,系对第151条要件和效果的修改,故不建议从“显失公平”的角度认定此类条款的效力。可基于实务经验并运用动态系统理论重构效力审查体系,以公平原则为“尺”,以对待给付失衡、意思自治、商事风险负担、违约金的性质以及违约金调整权的规范属性等因素为“度”,综合判断违约金调整排除特约的效力。

机车驾驶室垂向动力学建模与舒适性问题研究

为了研究机车在行驶过程中不同速度下的机车驾驶室座椅地板的振动情况,判断其不同速度下的舒适性,降低机车驾驶人员在振动环境中引起职业病的可能性。本文应用子结构法构建了机车多体动力学模型,计算了在不同行驶速度工况下的驾驶室座椅地板处的振动加速度,结合舒适性标准确定不同速度下驾驶室座椅舒适性情况;针对120 km/h行驶速度计算宽轨电力机车驾驶室座椅地板处的随机动态响应,明确其峰值最大值所在的频率范围。分析结果表明:随着速度的提高,宽轨电力机车的驾驶室座椅地板的垂向振动加速度明显增大,舒适性等级由1级变为3级,舒适性明显降低。在频率点16.489 Hz和18.815 Hz时振动位移和振动加速度会产生峰值。

拟禾本科根结线虫种群密度与旱稻产量损失的关系

本研究旨在探讨土壤中拟禾本科根结线虫(Meloidogyne graminicola)的初始种群密度对旱稻产量损失的影响。通过室外网室盆栽试验,在旱种旱管模式下测定了土壤不同初始种群密度对旱稻产量和线虫繁殖的影响。研究结果表明,在2~200个卵和二龄幼虫/100 cm^(3)土的初始种群密度下,旱稻根长、根重、株高、分蘖数、穗长、千粒重和单盆谷粒重与土壤线虫初始种群密度呈极显著负相关,符合一元回归方程;旱稻产量随着土壤初始种群密度的增加,其损失率增加,在初始密度为2个卵和二龄幼虫/100 cm^(3)土时,旱稻产量损失率为28.4%,接种密度为200个卵和二龄幼虫/100 cm^(3)土时,损失率最大,为67.8%;随着线虫初始种群密度的增加,线虫的繁殖系数呈现降低的趋势。利用Seinhorst模型,初始线虫种群密度与相对产量的关系式为Y=0.24+0.76(0.3252)(Pi)。在旱种旱管模式下,拟禾本科根结线虫在2~200个卵和二龄幼虫/100 cm^(3)土的初始种群密度下与旱稻产量损失呈极显著正相关,表明拟禾本科根结线虫对旱稻的危害风险性较高。

Reduced Dynamic Orbit Determination Using Differenced Phase in Adjacent Epochs for Spaceborne Dual-frequency GPS

We study on reduced dynamic orbit determination using differenced phase in adjacent epochs for spacebome dual-frequency GPS. This method not only overcomes the shortcomings that the epoch-difference kinematic method cannot be used when observation geometry is poor or observations are insufficient, but also avoids solving the ambiguity in the zero-difference reduced dynamic method. As the epoch-difference method is not sensitive to the impact of phase cycle slips, it can lower the difficulty of slip detection in phase observation preprocessing. In the solution strategies, we solve the high-dimensional matrix computation problems by decomposing the long observation arc into a number of short arcs. By gravity recovery and climate experiment （GRACE） satellite orbit determination and compared with GeoForschungsZentrum （GFZ） post science orbit, for epoch-difference reduced dynamic method, the root mean squares （RMSs） of radial, transverse and normal components are 1.92 cm, 3.83 cm and 3.80 cm, and the RMS in three dimensions is 5.76 cm. The solution＇s accuracy is comparable to the zero-difference reduced dynamic method.

Efficient Currency Determination Algorithms for Dynamic Data

Data quality is an important aspect in data application and management, and currency is one of the major dimensions influencing its quality. In real applications, datasets timestamps are often incomplete and unavailable, or even absent. With the increasing requirements to update real-time data, existing methods can fail to adequately determine the currency of entities. In consideration of the velocity of big data, we propose a series of efficient algorithms for determining the currency of dynamic datasets, which we divide into two steps. In the preprocessing step, to better determine data currency and accelerate dataset updating, we propose the use of a topological graph of the processing order of the entity attributes. Then, we construct an Entity Query B-Tree （EQB-Tree） structure and an Entity Storage Dynamic Linked List （ES-DLL） to improve the querying and updating processes of both the data currency graph and currency scores. In the currency determination step, we propose definitions of the currency score and currency information for tuples referring to the same entity and use examples to discuss methods and algorithms for their computation. Based on our experimental results with both real and synthetic data, we verify that our methods can efficiently update data in the correct order of currency.

Comparison of direct and indirect determinations of dynamic ventilation rate in a modern dairy free stall barn

Reliable estimation of the ventilation rate(VR)in intensive livestock buildings is necessary for studying building environmental control strategies and predicting indoor air quality and air emissions.As direct air exchange measurements are time-consuming and expensive,it is environmentally inefficient to measure livestock building VR continuously in practice.Hence,indirect VR estimation methods have been widely used in modelling environmental control and air emissions,and also to measure airflow in the field.The accuracy of indirect measurement methods needs to be evaluated by comparing with direct measurements.In this study,the direct and indirect methods of determining hourly and daily mean VRs were applied to a mechanically-ventilated dairy free stall barn monitored by the 24-month National Air Emissions Monitoring Study.The direct method was used to continuously monitor fan rotational speeds,and differential static pressures,coupled with periodic in-situ fan performance assessments,to calculate the VR.The indirect method consisted of estimating the VR using CO2 concentration measurements and the CO2 mass balance method.The average daily and hourly means(mean±SD)of directly measured barn ventilation rates for two years were(246±73)m3/s and(245±77)m3/s,respectively.The average daily and hourly means(mean±SD)of barn ventilation rates estimated by the CO2 mass balance method were(287±93.4)m3/s and(287±118)m3/s,respectively.Correlation analyses showed a strong correlation between the indirect CO2 mass balance method and direct measurement methods(r=0.93 for daily means and r=0.85 for hourly means).

个人信息处理知情同意规则之检视:反思与修正

知情同意是个人信息处理的规则之一,而非原则。同意行为的性质可以从两方面理解,在积极层面上是意思表示,消极层面上是免责事由。随着大数据的发展,知情同意规则遭遇挑战,同意愈发形式化,不足以充分保障信息主体权益。通过构建场景制度和动态同意制度两种方式对知情同意规则进行修正,前者是指将具体场景下的合理使用替代信息主体同意作为个人信息处理的合法性基础;后者旨在使知情同意成为一个持续的过程。

基于电力大数据的分布式电网异常负荷动态检测方法

电网负荷数据基数大、分布范围广,且其异常状态检测复杂度高。提出一种基于电力大数据分布的电网异常负荷动态检测方法。采用非线性回归方程,估计中心负荷权重,并分割动态检测区域。采用状态估计法结合参数平滑对异常的负荷数据进行状态估计,并利用自回归滤波(extended Kalman filter,EKF)剔除噪声数据。计算负荷数据的近相似系数,划分异常数据域,设定分布概率较高的数据为异常负荷数据。通过观测负荷数据与异常域中心之间的关联性,判断负荷是否存在异常问题。仿真实验结果表明:高信噪比环境下,该方法检测异常负荷数据的最大特征量为160条;低信噪比环境下,异常负荷数据的最大特征量为158条,且峰值出现在节点51—节点120的位置。检测出的负荷数量均超过电网最大阈值,说明所提方法能够精确检测出异常负荷,且能够完全包含真实阈值,检测的全面性可高达100%。

动态显色法检测能力验证样品中细菌内毒素的含量

目的:检测中国食品药品检定研究院下发的能力验证样品中细菌内毒素的含量。方法:选用光度测定法中的动态显色法,建立细菌内毒素检查的标准曲线,通过测定样品外加内毒素的回收率进行干扰试验,确定样品检测浓度线性范围,并测定样品中的细菌内毒素含量。结果:内毒素检测浓度线性范围为0.005~50 EU·mL^(-1)(|r|值均大于0.980);样品检测与标准曲线检测变异系数(CV)均小于10%;细菌内毒素回收率为50%~200%;两批能力验证检测结果分别为12.21 EU·mL^(-1)和93.24 EU·mL^(-1)。结论:动态显色法测定该能力验证样品的检测方法可靠、结果准确,可用于能力验证的盲样细菌内毒素含量测定。

“重大误解”法律适用的动态体系论

我国《民法典》及司法解释将“重大误解”制度设置为一般条款,虽然赋予法律适用以弹性空间,但在司法认定中产生了差异化样态。动态体系论既能克服概念法学的僵化保守,又能约束自由法学的恣肆,其在适用领域、保障规范条款的确定性和稳定性方面具有成为“重大误解”制度实践方法的正当化基础。首先,“重大误解”制度应将“误解的重大性”和“意思表示瑕疵”作为动态评价要素;其次,“误解的重大性”的判断基础来源于“错误认识”对象的三个层次与“通常理解”三种解释路径的一一对应,“意思表示瑕疵”应当将“强制作出意思表示”设为判断基础;最后,在各评价要素被判断基础检验后进行协作联动从而取得个案中“重大误解”制度的法律效果。

蒙药材蓝盆花不同采收期的木樨草素含量动态变化研究

目的:测定人工种植窄叶蓝盆花不同采摘期的木樨草素含量,为蓝盆花资源的开发利用及采收加工提供依据。方法:采用高效液相色谱法(HPLC)以木樨草素作为指标,对不同采摘期的野生驯化蓝盆花药材进行含量测定,色谱条件:色谱柱为syncronis-C_(18)(250 mm×4.6 mm,5μm),流动相为以甲醇-0.1%磷酸溶液,流速为1.0 mL/min,检测波长为350 nm,柱温为30℃,进样量10μL,理论板数按木樨草素峰计算应不低于5000。结果:木樨草素在1.0μg/μL~20μg/μL浓度范围内与吸光度呈良好的线性关系。不同采收期蓝盆花的木樨草素含量差异显著,8月8日木樨草素含量高于7月23日、8月11日、8月16日、9月4日、9月14日。结论:蓝盆花不同生长时期木樨草素的含量发生变化,每年8月上旬大量采集有利于保证蓝盆花的产量和品质。