Comparative Study of Micro and Nano Size WO3/E44 Epoxy Composite as Gamma Radiation Shielding Using MCNP and Experiment

The radiation shielding characteristics of 50wt% WO3/E44 epoxy composite in various gamma energies from 80 keV to 1.33 MeV are investigated via the MCNP code. Thus two scales are considered for WOa filler particles： micro and nano with sizes of i #m and 5Onto, respectively. The simulation results show that W03 nano particles exhibit a larger increase in linear attenuation coefficient in comparison with micro size particles. Finally, validation of simulation results with the published experimental data shows a good agreement.

A Comparative Study of Dispersion Characteristics Determination of a Trapezoidally Corrugated Slow Wave Structure Using Different Techniques

The linear dispersion relation of a trapezoidally corrugated slow wave structure （TCSWS） is analyzed and presented. The size parameters of the TCSWS are chosen in such a way that they operate in the x-band frequency range. The dispersion relation is solved by utilizing the Rayleigh-Fourier method by expressing the radial function in terms of the Fourier series. A highly accurate synthetic technique is also applied to determine the complete dispersion characteristics from experimentally measured resonances （cold test）. Periodic structures resonate at specific frequencies when the terminals are shorted numerical calculation, synthetic technique and cold appropriately. The dispersion characteristics obtained from test are compared, and an excellent agreement is achieved.

Comparative Study on Riparian Vegetation Buffers in Different Land Uses

This study focused on riparian vegetation buffer zones on the basis of low influence development(LID) and landscape restoration. Three types of land were selected to conduct comparative study. The types are buffers in urban districts,buffers in rural areas,and buffers in natural regions. These types basically reflect major ecological issues in different landuses. The follow conclusions were drawn:(1) there are different ecological issues in these 3 types,making the functions of buffers different.(2) The 3 types demand different ecological issues to be solved: Type A,functionally-diverse riparian landscape should be planned to enrich recreational activities and improve river's condition. Type B,agricultural areasource pollution needs to be cut down to sustain the stability of water conservation and ecological system. Type C,eco-conservation and various habitats for creatures are required.(3) Different planning methods were used respectively in the 3 types,construction methods were proposed for each type correspondingly and expressed in graphical ways in expectation of being instructive to the construction of eco-riparian landscape.

A Study on the Allocation of New Construction Land Use Indicators in Huai'an City

This paper makes a comprehensive analysis on the characteristics and influencing factors of regional allocation of new construction land use indicators,and determines the primary indicators from social,economic,external and internal factors.Using Delphi method and correlation analysis,this paper selects indicators and establishes evaluation indicator system.Using entropy method and AHP,this paper determines the weight of indicators,rationally allocates new construction land,and uses the actual data in Huai'an City for case studies,so as to provide a reference for land use planning.In addition,this paper makes a comparative analysis on the land use internal factors as important factors,in order to make the weight assigning more in line with the actual situation of construction land in Huai'an.

Current Research Situations,Problems and Recommendations of Land Use Structure and Layout Optimization

Land is the foundation for human survival and development,and all human social and economic activities are inseparable from the land as a space carrier.With the continuous development of China's social economy,China is facing new social development needs such as urban-rural integration and rural revitalization.At the same time,China starts to attach great importance to ecology and has proposed the concept that lucid waters and lush mountains are invaluable assets.In this situation,the rational use of land resources,the optimization of land use structure and layout are also facing new challenges and problems,and more comprehensive consideration is required to make relevant optimization.Using the method of literature comparative analysis,from the conceptual connotation,basic theory,method model,and specific practice of land use structure and layout optimization,this paper analyzed and summarized the current research situations and problems,and finally came up with recommendations for the future research.

Analysis of Land Use Change and Driving Factors in Mojiang County Based on PLUS Model

[Objectives]To explore the characteristics of land use change and its main influencing factors in Mojiang County from 2000 to 2020,and try to provide a scientific reference for alleviating the contradiction between man and land in Mojiang County and realizing the sustainable development of regional land resources.[Methods]Based on the land cover data and socio-economic data of Mojiang County from 2000 to 2020,the dynamic degree of land use,land use transfer matrix and center-of-gravity transfer model were calculated,and the temporal and spatial change characteristics and driving factors of various types of land use were calculated by PLUS model.[Results]From 2000 to 2020,the area and proportion of grassland,waters and construction land in Mojiang County showed an upward trend,while the area and proportion of cultivated land and forest land showed a downward trend.Among them,cultivated land was mainly converted into forest land and grassland,and some were converted into waters and construction land;forest land was mainly converted into cultivated land and grassland,and part of it was converted into waters and construction land.From 2000 to 2020,the center-of-gravity of cultivated land,forest land and construction land in Mojiang County moved to the southeast of the county,and the moving rates were 0.66,1.97 and 10.58 km/yr,respectively;the center-of-gravity of grassland and waters moved to the southwest of the county,and the moving rates were 1.30 and 20.20 km/yr,respectively.Distance from road,distance from government and distance from waters are the main driving forces affecting land use change in Mojiang County;the forecast shows that in 2040,the area of grassland and forest land in Mojiang County will continue to decrease,the area of cultivated land will turn to rise,and the area of waters and construction land will continue to rise.[Conclusions]Reasonable planning and optimizing the allocation of cultivated land and forest land structure and strict control of the expansion scale of construction land are necessary measures to ensure the coordinated development of regional land rational use and economic construction.

A study of the strong pulses detected from PSR B0656+14 using the Urumqi 25-m radio telescope at 1540 MHz

We report on the properties of strong pulses from PSR B0656＋14 by analyzing the data obtained using the Urumqi 25-m radio telescope at 1540 MHz from August 2007 to September 2010.In 44 h of observational data,a total of 67 pulses with signal-to-noise ratios above a 5σthreshold were detected.The peak flux densities of these pulses are 58 to 194 times that of the average profile,and their pulse energies are 3 to 68 times that of the average pulse.These pulses are clustered around phases about 5-ahead of the peak of the average profile.Compared with the width of the average profile,they are relatively narrow,with the full widths at half-maximum ranging from 0.28 ° to 1.78 °.The distribution of pulse-energies follows a lognormal distribution.These sporadic strong pulses detected from PSR B0656＋14 have different characteristics from both typical giant pulses and its regular pulses.

经口腔前庭腔镜手术与颈部开放手术治疗甲状腺乳头状癌的临床研究

目的探讨经口腔前庭入路腔镜甲状腺切除术(endoscopic thyroidectomy using the oral vestibular approach,ETOVA)与传统颈部开放手术治疗女性甲状腺乳头状癌的安全性、有效性及美容效果。方法回顾性分析2019年1~12月行甲状腺乳头状癌根治术的120例女性患者的临床资料,分为经口腔前庭入路腔镜甲状腺手术组(腔镜组,n=60)和传统颈部开放手术组(开放组,n=60),对比两组患者术中及术后相关临床资料。结果两组患者年龄、肿瘤直径、中央区淋巴结清扫时间、中央区淋巴结清扫总数、中央区转移淋巴结数量、术后并发症、术后24 h疼痛评分、术后6个月疼痛评分均无统计学差异(P均>0.05)腔镜组手术总时长、术中失血量、术后引流量均大于开放组(P均<0.001),腔镜组术后满意度高。结论ETOVA在治疗甲状腺乳头状癌是安全、有效的,具有更好的美容效果,患者满意度高,可以考虑作为部分患者,尤其是年轻女性甲状腺乳头状癌患者的首选手术方案。

Media as an Identity Negotiator Among ＂Swedish＂ Children in Athens and ＂Japanese＂ in London

With its transcultural perspective this paper looks at how families （i.e., parents and children） talk about children＇s identity and the importance of mothers＇ homeland media for the children, who are surrounded by a global popular media culture. Both studies used similar methods： interviews, participant observation, and photo-taking. The analysis shows the complexity of identity formation and the need to apply a contextual and relational perspective when wanting to understand the roles of media in the process of forming identity. The mothers＇ homeland media is an important construction tool in the process and helps the children not only with languages but also catch up with information about peers in mothers＇ homeland.

Functional trait differences between native bunchgrasses and the invasive grass Bromus tectorum

We conducted 30-and 60-d greenhouse experiments to compare functional traits of Bromus tectorum(invasive annual grass) and four perennial bunchgrasses under well-watered or drought conditions.Even under drought, B. tectorum experienced significantly less stress(i.e., higher xylem pressure potential and greater shoot water content, water use per day and water-use efficiency) and biomass production than the perennial grasses after 30 d. However, after 60 d, its superiority was reduced under infrequent watering. Differences among perennial grasses were more pronounced for physiological traits under infrequent watering and for morphological traits under frequent watering. Elymus multisetus(fastgrowing species) had a higher transpiration rate, lower leaf temperature, and lower water-use efficiency than the other grasses after 30 d. In contrast, Pseudoroegneria spicata(slow-growing) had lower xylem pressure potential and higher leaf temperature than all other grasses under infrequent watering. Under frequent watering, shoot dry mass and specific leaf area of B. tectorum was matched by Elymus wawawaiensis(moderate-growing species). Our results indicate that multiple-species plantings or seedings are necessary to foster greater weed resistance against B. tectorum. We also emphasize that when choosing plant material for restoration, performance during both pulse(resource-rich) and inter-pulse(resource-poor) periods should be considered.

Mass transfer mechanisms in fixed-bed adsorption of erythromycin

The equilibrium and kinetic characteristics of the adsorption of erythromycin to Sepabeads SP825 were determined.The equilibrium data in a batch system was well described by a Langmuir isotherm.The separation performance was investigated in a fixed-bed system with respect to the adsorption superficial velocity,ionic strength and pH.A mathematical model was used to simulate the mass transfer mechanism,taking film mass transfer,pore diffusion and axial dispersion into account.The model predictions were consistent with the experi-mental data and were consequently used to determine the mass transfer coefficients.

Comprehension of functional support by enculturated chimpanzees Pan troglodytes

Studies of causal understanding of tool relationships in captive chimpanzees have yielded disparate findings, particularly those reported by Povinelli ＆ colleagues （2000） for tool tasks by laboratory chimpanzees. The present set of experiments tested nine enculturated chimpanzees on three versions of a support task, as described by Povinelli （2000）, during which food re- wards were presented in different experimental configurations. In Experiment 1, stimulus pairs included a choice between a cloth with a reward on the upper right comer or with a second reward off the cloth, adjacent to a comer, with the second pair comprised of a cloth with food on the upper right comer, and a second cloth with the reward on the substrate, partially covered. All subjects were successful with both test conditions in Experiment 1. In a second study, the experimental choices included one of two possi- ble correct options, paired with one of three incorrect options, with the three incorrect choices all involving varying degrees of perceptual containment. All nine chimpanzees scored significantly above chance across all six conditions. In Experiment 3, four unique conditions were presented, combining one of two possible correct choices with one of two incorrect choices. Six of the subjects scored significantly above chance across the four conditions, and group performance on individual conditions was also significant. Superior performance was demonstrated by female subjects in Experiment 3, similar to sex differences in tool use previously reported for wild chimpanzees and some tool tasks in captive chimpanzees. The present results for Experiments 2 ＆ 3 were significantly differed from those reported by Povinelli et al. （2000） for laboratory-born, peer-reared chimpanzees. One contribution towards the dramatic differences between the two study populations may be the significant rearing and housing differences of the chimpanzee groups. One explanation is that under conditions of enculturation, rich social interactions with humans and conspecifics, as well as active exploration of artifacts, materials, and other aspects of their physical environment had a significant impact on the animals＇ ability to recognize the support relationships among the stimulus choices. Overall, the present findings provide strong support for the hypothesis that our chimpanzee subjects based their responses on an understanding of functional support which represented one facet of their folk physics repertoire [Current Zoology 57 （4）： 429-440, 2011].