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1. chinaXiv:202101.00052 [pdf]

Geochemical baseline determination and contamination of heavy metals in the urban topsoil of Fuxin City, China

ZHANG Hua; YU Miao; XU Hongjia; WEN Huan; FAN Haiyan; WANG Tianyi; LIU Jiangang
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

Urban topsoil is the most frequent interface between human society and natural environment. The accumulation of heavy metals in the urban topsoil has a direct effect on residents' life and health. The geochemical baseline of heavy metals is an objective description of the general level of heavy metals in the urban topsoil. Meanwhile, the determination of geochemical baseline is necessary for regional environmental management, especially in coal cities prone to heavy metal pollution. Heavy metal pollution has become an environmental problem in Fuxin City, China for a long time. To establish the geochemical baseline of heavy metals in the topsoil of Fuxin City and to evaluate the ecological risk of the topsoil, we collected 75 topsoil samples (0–20 cm) and analyzed the concentrations of Cu, Ni, Zn, Pb, Cr, Cd, Hg and As through X-ray fluorescence spectrometry, atomic absorption spectrometry and inductively coupled plasma optical emission spectrometry. We determined the geochemical baseline of heavy metals in the topsoil of Fuxin City by using iteration removal, box-whisker plot, cumulative frequency curve and reference metal normalization; evaluated the contamination risk and ecological risk of the topsoil by using the baseline factor index, Nemerow index and Hakanson potential ecological risk index; and identified the source category of heavy metals in the topsoil by using a pedigree clustering heatmap. Results showed that the geochemical baseline values were 42.86, 89.34, 92.23, 60.55, 145.21, 0.09, 0.08 and 4.17 mg/kg for Cu, Ni, Zn, Pb, Cr, Cd, Hg and As, respectively. The results of Nemerow index and Hakanson potential ecological risk index indicated that the urban topsoil in the study area was slightly contaminated and suffering low potential ecological risk. The main contaminated areas dominated in the middle part and northeast part of the study area, especially in the western Haizhou Strip Mine. The result of baseline factor index indicated that Hg and Cd were the major pollution elements. Using a pedigree clustering heatmap, we divided the sources of these heavy metals into three types: type I for Ni and Cr, largely represented the enrichment of heavy metals from natural sources; type II for Cu, Pb, Zn, Cd and As, mainly represented the enrichment of heavy metals from anthropogenic sources; and type III for Hg, represented the form of both natural and anthropogenic inputs.

submitted time 2021-01-15 From cooperative journals:《Journal of Arid Land》 Hits16Downloads5 Comment 0

2. chinaXiv:202010.00080 [pdf]

微波热点出现与维持的物理机制探讨

Jianyi Ma; Yongxin Hu
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

微波加热反应和传统加热反应相比有反应速度快、产率高等特点。微波反应中不同于传统加热的现象被称为“微波效应”。被观测到的微波效应包括热现象、热点现象、选择性加热等。理解和有效控制微波效应中的微波热点效应对理解和应用微波加热至关重要。基于我们2016年提出的微波反应量子态识别主方程模型,本文研究发现微波热点这种非线性现象的出现,宏观上与体系的温度的不均匀分布及微波强度有关,微观上与微波吸收导致的非平衡行为直接关联。本文建议可以通过预先加热反应容器中的空间局域点从而在该点诱发微波热点,也可以通过激发特定分子中的局域基团来诱导分子内热点的形成。可控微波热点效应有望应用在其它领域,本文的结论表明从量子态层面理解宏观非平衡和非线性行为的物理机制是必要的。

submitted time 2020-10-26 Hits3110Downloads276 Comment 0

3. chinaXiv:202010.00027 [pdf]

Evaluating agricultural water-use efficiency based on water footprint of crop values: a case study in Xinjiang of China

HAI Yang; LONG Aihua; ZHANG Pei; DENG Xiaoya; LI Junfeng; DENG Mingjiang
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

Efficient agricultural water use is crucial for food safety and water conservation on a global scale. To quantitatively investigate the agricultural water-use efficiency in regions exhibiting the complex agricultural structure, this study developed an indicator named water footprint of crop values (WFV) that is based on the water footprint of crop production. Defined as the water volume used to produce a unit price of crop (m3/CNY), the new indicator makes it feasible to directly compare the water footprint of different crops from an economic perspective, so as to comprehensively evaluate the water-use efficiency under the complex planting structure. On the basis of WFV, the study further proposed an indicator of structural water-use coefficient (SWUC), which is represented by the ratio of water-use efficiency for a given planting structure to the water efficiency for a reference crop and can quantitatively describe the impact of planting structure on agricultural water efficiency. Then, a case study was implemented in Xinjiang Uygur Autonomous Region of China. The temporal and spatial variations of WFV were assessed for the planting industries in 14 prefectures and cities of Xinjiang between 1991 and 2015. In addition, contribution rate analysis of WFV for different prefectures and cities was conducted to evaluate the variations of WFV caused by different influencing factors: agricultural input, climatic factors, and planting structure. Results from these analyses indicated first that the average WFV of planting industries in Xinjiang significantly decreased from 0.293 m3/CNY in 1991 to 0.153 m3/CNY in 2015, corresponding to an average annual change rate of –3.532%. WFV in 13 prefectures and cities (with the exception of Karamay) has declined significantly during the period of 1991–2015, indicating that agricultural water-use efficient has effectively improved. Second, the average SWUC in Xinjiang decreased from 1.17 to 1.08 m3/CNY in the 1990s, and then declined to 1.00 m3/CNY in 2011–2015. The value of SWUC was highly consistent with the relative value of WFV in most prefectures and cities, showing that planting structure is one of the primary factors affecting regional agricultural water-use efficiency. Third, the contribution rate of WFV variations from human factors including agricultural input and planting structure was much more significant than that from climatic factors. However, the distribution of agricultural input and the adjustment of planting structure significantly differed among prefectures and cities, suggesting regional imbalances of agricultural development. This study indicated the feasibility and effectiveness of controlling agricultural water use through increasing technical input and rational selection of crops in the face of impending climate change. Specifically, we concluded that, the rational application of chemical fertilizers, the development of the fruit industry, and the strict restriction of the cotton industry should be implemented to improve the agricultural water-use efficiency in Xinjiang.

submitted time 2020-10-20 From cooperative journals:《Journal of Arid Land》 Hits2864Downloads263 Comment 0

4. chinaXiv:201910.00072 [pdf]

不确定性原理与客观确定性判则

段德龙
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

[目的] 分析解决不确定性原理及量子理论在物理诠释方面的分歧。 [方法] 对海森堡不确定性原理数学关系式的原始推导、物理涵义以及爱因斯坦光子箱思想实验进行了重新检视分析,并考察了不同作用图景下该关系式的极限。 [结果] 在电磁作用图景下,通过对量子力学量的统计分布及其全概率空间的分析,首次获得了非统计诠释下的不确定性关系式在数学上被破坏的结果;利用傅里叶变换,导出了虚拟作用图景下相应共轭力学量的标准差约束关系式;通过考察电磁作用图景、引力作用图景以及虚拟作用图景所构成的集合,率先得到了微观量子客体力学状态的确定性判则;经过对爱因斯坦光子箱思想实验的重新检视分析,证伪了玻尔在索尔维会议上的论证结论。 [局限]未分析量子纠缠。 [结论] ①非统计诠释存在逻辑矛盾,不确定性关系、现行量子力学理论仅在统计诠释下,才能对微观量子客体在电磁作用图景中的力学状态作出恰当的描述;② 确定性判则显示,微观粒子的力学状态具有客观确定性,其波函数是对电磁作用图景下的微观粒子力学状态统计呈现相的表述;量子力学非统计诠释所指称的个体几率性实质是微观粒子与作用图景之间互作用统计呈现相的概率反映。

submitted time 2020-09-28 Hits22562Downloads1421 Comment 0

5. chinaXiv:202008.00089 [pdf]

On the description of particle system motion

吴峰
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

Based on the concepts of infinitesimal and super real time-space composed of monads, the equations describing the particle flow are proposed. After the initial conditions are given, the state of the particle system at any time can be obtained by solving these equations. The physical properties of the granular matter, such as the moving velocity, the rotation angle, the angular velocity of rotation, the temperature, the pressure, the density, the mass, etc. at any time and space position are obtained. It is also to obtain that the translational motion is not dependent on rotation motion ofthe particles and can be separately analyzed. For a stationary particle system, theconditions that must be met by the force and force moment on the particles in thesystem are given. On this basis, the properties of the granular matter at rest can befurther explored for.

submitted time 2020-08-25 Hits6020Downloads470 Comment 0

6. chinaXiv:202006.00241 [pdf]

Responses of leaf water potential and gas exchange to the precipitation manipulation in two shrubs on the Chinese Loess Plateau

LI Yangyang; CHEN Jiacun; AI Shaoshui; SHI Hui
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

Regulation of leaf gas exchange plays an important role in the survival of trees and shrubs under future climate change. However, the responses of leaf water potential and gas exchange of shrubs in semi-arid areas to the precipitation alteration are not clear. Here, we conducted a manipulated experiment with three levels of precipitation, i.e., a control with ambient precipitation, 50% above ambient precipitation (irrigation treatment), and 50% below ambient precipitation (drought treatment), with two common shrubs, Salix psammophila C. Wang & C. Y. Yang (isohydric plant, maintaining a constant leaf water potential by stomatal regulation) and Caragana korshinskii Kom. (anisohydric plant, having more variable leaf water potential), on the Chinese Loess Plateau in 2014 and 2015. We measured the seasonal variations of predawn and midday leaf water potential (?pd and ?md), two parameters of gas exchange, i.e., light-saturated assimilation (An) and stomatal conductance (gs), and other foliar and canopy traits. The isohydric S. psammophila had a similar An and a higher gs than the anisohydric C. korshinskii under drought treatment in 2015, inconsistent with the view that photosynthetic capacity of anisohydric plants is higher than isohydric plants under severe drought. The two shrubs differently responded to precipitation manipulation. ?pd, An and gs were higher under irrigation treatment than control for S. psammophila, and these three variables and ?md were significantly higher under irrigation treatment and lower under drought treatment than control for C. korshinskii. Leaf water potential and gas exchange responded to manipulated precipitation more strongly for C. korshinskii than for S. psammophila. However, precipitation manipulation did not alter the sensitivity of leaf gas exchange to vapor-pressure deficit and soil moisture in these two shrubs. Acclimation to long-term changes in soil moisture in these two shrubs was primarily attributed to the changes in leaf or canopy structure rather than leaf gas exchange. These findings will be useful for modeling canopy water-carbon exchange and elucidating the adaptive strategies of these two shrubs to future changes in precipitation.

submitted time 2020-06-22 From cooperative journals:《Journal of Arid Land》 Hits7902Downloads508 Comment 0

7. chinaXiv:202006.00200 [pdf]

关于手性问题的讨论.pdf

史志强
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

本文是对《中国科学》一个编者按的商榷和讨论。文章指出手性是手性对称性的破缺,并举例说明了手性对称性和手性的本质区别。手性化合物的一对对映体有不同的生物活性和药物活性,这决不是个别极端的例子,而是非常普遍存在的。生物体内参与蛋白质组成的氨基酸是手性的,但它们既不全都是左旋的,也不全都是右旋的,只能说它们全部都是L构型的。蛋白质的结构是复杂的,我们不能笼统地说蛋白质是右旋的,只能说蛋白质二级结构中的α-螺旋结构是右旋的。最后,我们分析了对手性定义的几种错误表述,并指出产生这些错误的原因。

submitted time 2020-06-17 Hits9007Downloads785 Comment 0

8. chinaXiv:201607.00046 [pdf]

Exact Solution for Three-Dimensional Ising Model

Zhang, Degang
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

Three-dimensional Ising model in zero external field is exactly solved by operator algebras, similar to the Onsager's approach in two dimensions. The partition function of the simple cubic crystal imposed by the periodic boundary condition along both $(0 1 0)$ and $(0 0 1)$ directions and the screw boundary condition along the $(1 0 0)$ direction is calculated rigorously. In the thermodynamic limit an integral replaces a sum in the formula of the partition function. A order-disorder transition in the infinite crystal occurs at a temperature $T=T_c$ determined by the condition: $\sinh\frac{2J}{k_BT_c}\sinh\frac{2(J_1+J_2)}{k_BT_c}=1$, where $(J_1 J_2 J)$ are the interaction energies in three directions, respectively. The analytical expressions for the internal energy and the specific heat are also given. It is also shown that the thermodynamic properties of 3D Ising model with $J_1=J_2$ are connected to those in 2D Ising model with the interaction energies $(J_1 J_{2D})$ by the relation $(\frac{J_{2D}}{k_BT})^*=(\frac{J}{k_BT})^*-\frac{J_1}{k_BT}$, where $x^*=\frac{1}{2}{\rm ln coth} x={\rm tanh}^{-1}(e^{-2x})$.

submitted time 2020-05-12 Hits29482Downloads2347 Comment 0

9. chinaXiv:202001.00062 [pdf]

基于环境示踪剂氯的北山地区浅部地下水补给研究

李杰彪; 苏锐; 周志超; 郭永海; 季瑞利; 张明; 王洪斌
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

地下水补给研究是高放废物深地质处置库选址和场址评价的重要研究内容之一。甘肃北山地区是我国高放废物地质处置库场址首选预选区,为查明该区地下水补给特征,基于环境示踪剂氯查明了北山地区浅部地下水补给量。结果表明:(1) 总体而言,氯质量平衡方法在北山地区应用效果较好。(2) 基于包气带的氯质量平衡方法计算得出的浅部地下水垂向补给量在渗透性较大的沟谷盆地中为0.07~2.03 mm·a-1,平均值约1.0 mm·a-1。(3) 基于饱和带的氯质量平衡方法计算得出北山地区浅部地下水多年平均入渗补给量为0.25 mm·a-1,不足多年平均降水量的0.5%。相关结果可为我国高放废物地质处置库选址和场址评价提供依据。

submitted time 2020-01-06 From cooperative journals:《干旱区地理》 Hits13422Downloads866 Comment 0

10. chinaXiv:201910.00053 [pdf]

Effects of biochar on water movement characteristics in sandy soil under drip irrigation

PU Shenghai; LI Guangyong1; TANG Guangmu; ZHANG Yunshu ; XU Wanli; LI Pan; FENG Guangping; DING Feng
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

Biochar addition can improve the physical and hydraulic characteristics of sandy soil. This study investigated the effects of biochar on water holding capacity and water movement in sandy soil under drip irrigation. By indoor simulation experiments, the effects of biochar application at five levels (0%, 1%, 2%, 4% and 6%) on the soil water retention curve, infiltration characteristics of drip irrigation and water distribution were tested and analyzed. The results showed that biochar addition rate was positively correlated with water holding capacity of sandy soil and soil available water. Within the same infiltration time, with an increasing amount of added biochar, the diffusion distance of the horizontal wetting front (HWF) tended to decrease, while the infiltration distance of vertical wetting front (VWF) initially declined and then rose. The features of wetted bodies changed from "broad-shallow" to "narrow-deep" type. The relationship between the transport distances of HWF and VWF and the infiltration time was described by a power function. At the same distance from the point source, the larger the amount of added biochar, the higher the soil water content. Biochar had a great influence on the water content of the layer with biochar (0–200 mm) and had some effects at 200–250 mm without biochar; but it had less influence on the soil water content deeper than 250 mm. For the application rate of biochar of 4%, most water was retained within 0–250 mm soil layer. However, when biochar application amount was high (6%), it would be helpful for water infiltration. During the improvement of sandy soil, biochar application rate of 4% in the plow layer had the best effect.

submitted time 2019-10-26 From cooperative journals:《Journal of Arid Land》 Hits16840Downloads1083 Comment 0

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