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1. 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》 Hits4Downloads2 Comment 0

2. chinaXiv:201910.00072 [pdf]


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 Hits15286Downloads1043 Comment 0

3. chinaXiv:202008.00089 [pdf]

On the description of particle system motion

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 Hits2883Downloads252 Comment 0

4. 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》 Hits5175Downloads352 Comment 0

5. chinaXiv:202006.00200 [pdf]


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


submitted time 2020-06-17 Hits5739Downloads493 Comment 0

6. 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 Hits25125Downloads2190 Comment 0

7. chinaXiv:202001.00062 [pdf]


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》 Hits11513Downloads724 Comment 0

8. 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》 Hits14558Downloads905 Comment 0

9. chinaXiv:201909.00120 [pdf]


李淑霞; 刘亚斌; 钟鹏; 余冬梅; 胡夏嵩; 杨幼清
Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

以西宁盆地长岭沟流域自建试验区为研究区,筛选出适宜当地气候条件下生长的2种灌木植物柠条锦鸡儿(Caragana korshinskii Kom.)、霸王〔Zygophyllum xanthoxylon (Bunge) Maxim.〕和2种草本植物细茎冰草(Agropyron trachycaulum cv. Slender)、紫花苜蓿(Medicago sativa Linn.)作为试验供试种,在试验区对4种植物采用单一种植和组合种植方式,探讨2种种植条件下植物根系在边坡地表以下垂直方向土体中K+、Ca2+、Na+、Mg2+、SO42-、Cl-、HCO3-、CO32-等8种易溶盐离子含量及其变化特征,评价了区内2种草本和2种灌木植物降低边坡土体盐分的能力。结果表明:单一种植细茎冰草、紫花苜蓿、柠条锦鸡儿、霸王对边坡土体中SO42-、Ca2+、Na+具有显著降低作用,草本与灌木组合Ⅰ(柠条锦鸡儿+紫花苜蓿+细茎冰草组合)和草本与灌木组合Ⅱ(霸王+紫花苜蓿+细茎冰草组合)对边坡土体中SO42、Ca2+、Mg2+、K+、Na+表现出显著降低作用;紫花苜蓿的降盐效果相对较为显著、其次为柠条锦鸡儿和细茎冰草,霸王的降盐效果不及前者显著;草本与灌木组合Ⅱ的降盐效果相对显著于草本与灌木组合Ⅰ。

submitted time 2019-09-09 From cooperative journals:《干旱区研究》 Hits14821Downloads713 Comment 0

10. chinaXiv:201907.00026 [pdf]

Exact Solution of Quantum Rabi Model

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

Quantum Rabi model is exactly solved by employing the parameter-dependent unitary transformation method in the Bargmann space. The complete energy spectrum consists of two double-fold sub-energy spectra. The eigenvalue is determined by the parameter in the unitary transformation, which satisfies a highly nonlinear equation. Such the energy spectrum completely coincides with that obtained in the occupation number representation [D. Zhang, chinaXiv:201708.00168].

submitted time 2019-07-31 Hits14727Downloads828 Comment 0

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