浅议“动·数·动量”格式之形成

先秦时期动量关系的表现,以"数·动"格式为主。动量词产生并广泛使用后,并未依照先秦表量的主要方式,而是采用了"动·数·动量"格式。此格式逐渐占据主导地位,延用至今。从"数·动"到"动·数·动量"的转化,并不是随意的,而是有着深层次的原因,是汉语自身发展完善的结果。

Dynamics of Soil Fauna in Da Hinggan Mountains, Northeast China

The dynamics of soil animals was studied in seven representative forest communities in the north of the Da Hinggan Mountains, Northeast China. The results indicate that it was distinctive in the changes of the numbers of soil animals and groups and diversity in relationship with seasons for macrofauna and meso-micro fauna in the study area. The numbers of the observed soil animals in different months were: October>August>June. Group number was larger in August and October, but smaller in June. The change of diversity index in different months was: August>June>Oc- tober. The biomass for macrofauna in different months was: October>June>August. The composition and number of each functional group was relatively stable. In the community of the predominant soil environment, the percentage of saprophagous animals was higher than carnivorous animals and herbivorous animals. The dynamics changes of sapro- phagous and carnivorous animals were distinctive, increasing from June to October, while the change of herbivorous animals was unremarkable.

Status and distribution changes of the endangered Green Peafowl (Pavo muticus) in China over the past three decades (1990s-2017)

Background： Understanding the changes in population dynamics, including demographics, distribution and threats is essential for species status assessing.The endangered Green Peafowl （Povo muticus） has experienced sharp population declines and d stribution range diminishing both in China and Southeast Asia. Field population surveys have not been conducted in China since the 1990s, which hindered conservation planning and decision-making.Methods： With interview and line transects methods, we figured out the population and distribution changes of Green Peafowl across its historical ranges over the past three decades in China during 2014-2017.Results： The Green Peafowl once habituated in 54 counties in China. Nearly 60% of the distribution counties were lost in the past three decades, with the left 22 counties distributed in central, southern and western Yunnan, SW China. Population decrease detected in all distribution areas except for Shuangbai and Xinping county where more than 60% of the total population is located. Only about 30% of the former bird population were recorded with the same interviewing method as 20 years ago.Three birds, 1 carcass, 6 calls and 12 footprints were detected along the 865 km line transects, indicating extremely low encounter rate of Green Peafowl in field. Sharp decreases in flock sizes were also detected, from 8-20 birds per flock in the 1990s to 3-5 birds at present. Poaching and habitat conversion are two widespread and long-lasting threats, while poison tion affect regional population＇s survival. Large flocks of 18 ng caused mortality in the past and hydropower construc -27 birds were discovered in the field, which increases our confidence of population recovery of this endangered pheasant in China.Conclusions： Only interviewed bird number and counts based on line transects were presented in this study, without further population estimation due to limitation of the data sets. Although the actual population of this cryptic bird must be underestimated, dramatic population declines and distribution concentrations of the endangered Green Peafowl occurred over the past 30 years in China undoubtedly.

Theoretical Study on Quantum Dynamics for Ar-HF Inelastic Collision

The integral cross sections and rate constants of pure rotational and ro-vibrational energy transfer processes for the Ar-HF system are thoroughly studied by using the timeindependent close coupling method based on our newly constructed potential energy surface. Compared to previous theoretical results, pure rotational transitions in this work achieve better agreement with the experimental data. For ro-vibrational energy transfer, it is found that quasi-resonant transitions dominate the cross sections in all cases. Furthermore, the vibrational-resolved rate constant of transition v=1→v=0 increases very quickly with the temperature from 100K to 1500K and is also in good agreement with the available experimental results.

Dynamics of Meandering Spiral Waves Driven by Two-Point Feedback

We numerically study the dynamics of meandering spiral waves in the excitable system subjected to a feedback signal coming from two measuring points located on a straight line together with the initial spiral core. The core location and size radius of the final attractors are computed, and they change with the position of the moving measuring point in a unique way. By the Fourier Spectral analysis, we find the frequency-locked behaviors different from the driving scheme of the external periodic force. It when the moving measuring point approaches closely is also found that the meandering spiral wave can be eliminated the boundary and its feedback gain is large enough. This offers an effective and convenient method for eliminating meandering spiral waves.

Pressure Drop Fluctuations in Periodically Fluctuating Pipe Flow

Experiments were conducted to study characteristics of flow when flow is fluctuating.The experimental results showed a phase difference between the flow rate and the pressure drop fluctuations.This phase difference between the fluctuating flow rate and pressure drop was analyzed for laminar flow.Analysis showed that the phase difference changes with the period of the flow fluctuation, the pipe radius, the density and the dynamic viscosity of the liquid.Fluctuating pipe flow was then numerically simulated.Results of the numerical simulation were compared with theoretical values and experimental results.It was shown that, when the flow rate fluctuates with time as a sine wave, the pressure drop fluctuates with the same periodicity, and there is a phase difference between them.

Comparison of daily physical activity parameters using objective methods between overweight and normal-weight children

Purpose: The purpose of the present study was to determine if there were any differences in various aspects of physical activity such as energy expenditure, intensity, and type of activity between normal-weight and overweight boys.Methods: Children aged 9—12 years were recruited from 2 elementary schools located in different urban districts in Republic of Korea. The present study included 45 Korean boys, of which 19 were normal-weight and 26 were overweight. Daily physical activity was estimated over the same 1-week study period under free-living conditions using the doubly labeled water(DLW) method and a tri-axial accelerometer. Resting metabolic rate(RMR) was measured using the Douglas bag method and open-circuit indirect calorimetry. We calculated the physical activity level(PAL) as the total energy expenditure(TEE)/RMR.Results: PAL was not significantly different between the groups. In the accelerometer data, time spent in locomotive moderate-to-vigorous physical activity(MVPA) was significantly lower in overweight boys than in normal-weight subjects, whereas other variables including non-locomotive activity did not differ between groups. In addition, among all participants, time spent in total locomotive activity was significantly associated with PAL. Time spent in locomotive MVPA was significantly associated with PAL.Conclusion: Overweight boys may be less physically active based on locomotive MVPA, which was positively related with PAL. Our findings suggest that the contribution of locomotive MVPA to the increase in PAL was relatively significant.

Dynamic simulation and efficiency analysis of beam pumping system

An improved whole model of beam pumping system was built. In the detail, for surface transmission system(STS), a new mathematical model was established considering the influence of some factors on the STS's torsional vibration, such as the time variation characteristic of equivalent stiffness of belt and equivalent rotational inertia of crank. For the sucker rod string(SRS), an improved mathematical model was built considering the influence of some parameters on the SRS's longitudinal vibration, such as the nonlinear friction of plunger, hydraulic loss of pump and clearance leakage. The dynamic response and system efficiency of whole system were analyzed. The results show that there is a jumping phenomenon in the amplitude frequency curve, and the system efficiency is sensitive to motor power, pump diameter, stroke number, ratio of gas and oil, and submergence depth. The simulation results have important significance for improving the efficiency of beam pumping system.

The Energy Optimization Mathematic Algorithm on Multi-energy Resource Powertrain of Fuel Cell Vehicle

In order to solve the core issue of the energy regulation （ER） on multi-energy resource powertrain of fuel cell vehicle, the work functions of each component were defined; the mathematical algorithm model of energy regulation was established and the relevant solution was found. This algorithm was evaluated successfully on the hardware in loop （FILL） platform under three typical urban running cycles. The results showed ER control target had been realized and the mathematical algorithm was effective and reasonable. Based on the HIL simulation, some conclusions and ER strategies were made. According to the different power component parameters and real time control request, this algorithm should be modified and calibrated for application in the actual control system.

Difference of Directions Between External Driving Force and Movement Direction of Center of Mass

Driven dynamics of a two-dimensional Frenkel-Kontorova model is studied in the paper.In our numericalsimulations, it is found that the movement direction of the center of mass is not consistent with that of the externaldriving force except for some special symmetric directions at the lower driving force.Our results also indicate that themovement direction of the center of mass strongly depends on both the magnitude and the direction of the externaldriving force as well as the misfit angle between two layers.

Weigh in Motion Based on Parameters Optimization

Dynamic tire forces are the main factor affecting the measurement accuracy of the axle weight of moving vehicle.This paper presents a novel method to reduce the influence of the dynamic tire forces on the weighing accuracy.On the basis of analyzing the characteristic of the dynamic tire forces,the objective optimization equation is constructed.The optimization algorithm is presented to get the optimal estimations of the objective parameters.According to the estimations of the parameters,the dynamic tire forces are separated from the axle weigh signal.The results of simulation and field experiments prove the effectiveness of the proposed method.

Dependence of Consumption Volume on the Labor-Force in One-Productive Models of Economic Dynamics

In the work one-productive model of economic dynamics the labor-force involved in production is investigated the case when or function with constant elasticity of substitution （CES） is studied. is considered. The dependence of the consumption volume on production function coincides with the Cobb-Douglas function

Unidirectional Rotary Tendency of a Wave-Driven Rotor

Ocean waves can directly drive WECs （wave energy converters） to perform two types of motion--reciprocating motion and unidirectional rotary motion. In general, the efficiency of a reciprocating WEC is strongly wave-frequency dependent, whereas the efficiency of a rotary WEC can be somewhat wave-frequency independent. To date, a huge majority of WEC technologies under development in industry belong to the reciprocating class, and only a few WEC concepts fall in the unidirectional rotary class. In the present work, a wave-driven rotor for unidirectional rotary motion was proposed and characterized. A numerical tool has been developed for characterization of the rotor＇s unidirectional rotary tendency. The tool included a wave model and a drag force model. Simple circular tubes were used as blades in a basic rotor design. This basic design demonstrated strong potential for unidirectional rotary motion at a proper rotor submersion level and under various wave conditions. Two improved designs were yielded from the basic design. In one improved design, the original circular tubes were replaced with cylindrical shells of semicircular cross section as new blades. In another design, the semicircular shells were further modified to become one-way foldable. The two improvements significantly enhanced the rotors＇ unidirectional rotary tendency in waves, which has been verified by numerical simulation. Broad ranges of wave parameters and the submersion level have been numerically explored on the two improved rotor designs in conjunction with dimensional analysis.

Response of endemic afroalpine rodents to the removal of livestock grazing pressure

The Bale Mountains of Ethiopia represent the world＇s largest continuous extent of afroalpine habitat. With a peak combined density of over 8000 individuals/km2, the endemic giant mole rat Tachyoryctes macrocephalus, Blick＇s grass rat Arvi- canthis blicki and the brush-furred mouse Lophuromys melanonyx are the dominant wild herbivores within this ecosystem and may be affected by the presence of high densities of domestic livestock. The purpose of this study was to establish whether these endemic rodent populations could respond to the removal of grazing pressure inside three 0.25 hectare livestock exclosures （paired with grazed control plots） and to determine whether such response was mediated through concomitant changes in the vegetation structure. We hypothesised that livestock grazing negatively affects endemic rodent populations through competition or increased predation risk and we predicted an increase in rodent biomass following the removal of grazing pressure. We found no evidence of rodent populations responding to the removal of livestock after fourteen months. The short-term nature of the ex- perimental design, environmental fluctuations and the ecosystem＇s inherent stochasticity may explain the apparent lack of a sig- nificant response. However, while this study is inconclusive, it emphasises the need for more long-term experimental investiga- tions to assess the effects of domestic grazers on vegetation and on dependent communities. The effects of rapidly increasing livestock numbers in the Bale Mountains will require continued close monitoring of vegetation and endemic animal communities as the afroalpine is altered by external biotic and abiotic forces .

Structural finite element model updating using incomplete ambient vibration modal data

This paper presents an effective approach for updating finite element dynamic model from incomplete modal data identified from ambient vibration measurements.The proposed method is based on the relationship between the perturbation of structural parameters such as stiffness and mass changes and the modal data measurements of the tested structure such as measured mode shape readings.Structural updating parameters including both stiffness and mass parameters are employed to represent the differences in structural parameters between the finite element model and the associated tested structure.These updating parameters are then evaluated by an iterative solution procedure,giving optimised solutions in the least squares sense without requiring an optimisation technique.In order to reduce the influence of modal measurement uncertainty,the truncated singular value decomposition regularization method incorporating the quasi-optimality criterion is employed to produce reliable solutions for the structural updating parameters.Finally,the numerical investigations of a space frame structure and the practical applications to the Canton Tower benchmark problem demonstrate that the proposed method can correctly update the given finite element model using the incomplete modal data identified from the recorded ambient vibration measurements.

Calculation of natural circulation under heaving motion

Wide validation of self-developed program of natural circulation under oceanic conditions has been conducted compared with experimental data of inclination,zero-power condition and hot-state condition.Experiments were performed on a full-scale,whole parameterization natural circulation loop designed with reference to 5 MW experimental low temperature nuclear heating reactor(NHR)of Tsinghua University.Investigation of natural circulation and parameter effect under heaving motion was carried out using the program and comparison of heaving,inclination and rolling on natural circulation respectively to reveal the influence mechanism.Results indicate that:(1)significant influence of heaving motion on natural circulation was observed,and heaving motion with high level of strength and long cycle would lead to severe flow fluctuation;(2)slight effect was caused by short cycle heaving motion which was completely different from long cycle heaving motion;(3)comprehensive action of alternating force and flow density distribution would result in natural circulation under heaving motion;(4)most severe accidents maybe result from the long cycle heaving motion rather than inclination and rolling motion.Investigation of influence of heaving motion on natural circulation could have important reference significance in the optimization design of nuclear reactors.

A novel tuned heave plate system for heave motion suppression and energy harvesting on semi-submersible platforms

Deepwater offshore structures such as semi-submersible platforms suffer powerful ocean waves due to their location and site condition. The long distance away from the shore also brings many difficulties to energy supply for the platform operation. How to reduce the response of the platform and convert the wave energy into electrical power is a meaningful topic. In this paper, a tuned heave plate system(THP) is presented and designed to be employed on a semi-submersible platform for heave motion suppression and energy harvesting. This THP system is composed of spring supports, a power take-off system(PTO), and a heave plate. The PTO system is a permanent magnet linear generator(PMLG), which could directly convert the kinetic energy of the heave plate into electronic power. The stiffness of the spring supports is designed based on the principle of the tuned mass damper(TMD). The numerical model of the platform and the THP system is established according to the hydrodynamic analysis results of the platform. The model is tested and modified by scale model tests on the platform in the wave tank. A parameter study, including the size, tuned period, and damping ratio of the THP system, is conducted systematically based on the numerical model. The optimal parameters of the THP are selected due to the maximum heave motion reduction under severe wave conditions in South China Sea. The performance of the semi-submersible with and without the THP system under different wave conditions is analyzed. It is demonstrated that this novel tuned heave plate system could reduce the heave motion of the semi-submersible platform significantly and generate considerable power, which makes the THP system have a broad prospect for development.

FLOW OF MICROPOLAR FLUID THROUGH CATHETERIZED ARTERY -- A MATHEMATICAL MODEL

In this paper, the flow of blood through catheterized artery with mild constriction at the outer wall is considered. The closed form solutions are obtained for velocity and microrotation components. The impedance （resistance to the flow） and wall shear stress are calculated. The effects of catheterization, coupling number, micropolar parameter, and height of the stenosis on impedance and wall shear stresses are discussed.