China is the world's most populous country and a major emitter of greenhouse gases. Consequently, much research has focused on China's influence on climate change but somewhat less has been written ...about the impact of climate change on China. China experienced explosive economic growth in recent decades, but with only 7% of the world's arable land available to feed 22% of the world's population, China's economy may be vulnerable to climate change itself. We find, however, that notwithstanding the clear warming that has occurred in China in recent decades, current understanding does not allow a clear assessment of the impact of anthropogenic climate change on China's water resources and agriculture and therefore China's ability to feed its people. To reach a more definitive conclusion, future work must improve regional climate simulations-especially of precipitation-and develop a better understanding of the managed and unmanaged responses of crops to changes in climate, diseases, pests and atmospheric constituents.
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Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The analysis of the psychological impact of the spread of Yangming studies in Japan on the Japanese people is to enable Yangming studies to be better developed in Japan. Based on big data analysis ...technology, this paper constructs a hybrid data analysis model using the EM algorithm and proposes performance evaluation indexes for the model. Under the EM data analysis model constructed in this paper, the example indicators of the Japanese people’s psychological impact in disseminating Yangming studies by big data analysis are explored, i.e., the psychological acceptability of the dissemination method and the psychological and moral construction impact. Regarding the dissemination method, the Japanese people are more receptive to disseminating Yangming studies in Japan through “learning rules”, with an average percentage of 39.37%. Regarding psychological and moral construction, 90.22% of the Japanese people believe that disseminating Yangming studies can promote self-improvement of value standards and correct self-examination. Based on the big data analysis, we can effectively see from the data the impact of Yangming studies on the audience in the process of dissemination, and improve the scope of Yangming studies dissemination according to the data feedback, so that more people can recognize the idea of unity of knowledge and action.
It is very significant to study the stress and displacement fields in the surrounding rock induced by the tunnel excavation and its support. First of all, in order to take into account the effect of ...the intermediate principal stress on the tunnel surrounding rock mechanical behavior, the unified strength criterion (USC) is adopted to describe the plastic yield behavior of the surrounding rock. Secondly, the model proposed by Kastner does not consider the effect of the initial elastic displacement of the tunnel surrounding rock before the support structure is constructed and the interaction between the surrounding rock and the support structure. Therefore, a new mechanical model for the circular tunnel, which can overcome these shortcomings, is finally proposed by considering the tunnel practical construction process on basis of Kastner’s method. The effects of the calculation parameters such as the intermediate principal stress coefficient
b
, the initial elastic displacement
u
0
at the tunnel wall, the rock internal friction angle and the stiffness
k
s
of the support structure on the surrounding rock plastic zone, and radial displacement of the tunnel wall are studied in detail. The results of the calculation examples show that the tunnel surrounding rock relative plastic zone
r
p
/
r
0
and ground radial displacement
u
s
of the tunnel wall decrease with increasing
b
. With increasing
u
0
,
r
p
/
r
0
and
u
s
both increase, while with increasing
k
s
and the rock internal friction angle,
r
p
/
r
0
and
u
s
both decrease. In sum, it indicates that the proposed model for the circular tunnel can perfectly reflect the tunnel mechanical behavior.
•We propose a method to calculate the microcrack propagation length under frost heaving pressure.•The variation law of rock elastic modulus with freezing-thawing cycles is established.•We propose the ...theoretical model for frost heaving pressure in circular rock tunnel.
The failure of rock tunnel lining in cold region involves the evaluation of frost heaving pressure in surrounding rock. Although many theoretical models of frost heaving pressure have been proposed, the combination effect of reduction in rock elastic modulus and increase of rock void ratio due to freezing-thawing cycles has not been considered. For this issue, on basis of the elastic model for frost heaving pressure in the circular tunnel surrounding rock, this study establishes the relationship between the rock elastic modulus and the number of freezing-thawing cycles based on fracture mechanics and mesodamage theory. Thereafter, we propose the damage model for frost heaving pressure by considering the combination of rock elastic modulus and void ratio. It is assumed that frost heaving pressure mainly occurs when water in microcracks is frozen into ice. The calculation example shows that frost heaving pressure gradually increases and tends to be a constant with increasing the number of freezing-thawing cycles. It indicates that the proposed model is capable of calculating the variation of frost heaving pressure with the number of freezing-thawing cycles.
Nonstructural carbohydrates (NSCs) facilitate the adaptation of trees to drought stress. There have been a large number of studies exploring NSC changes in individual plant species and individual ...organ under drought and showed different trends; however, an understanding of the universal pattern of the plant NSCs responses to drought, particularly to drought duration, is still lacking. Here, we compiled data from 47 experimental studies on 52 tree species and conducted a meta‐analysis to evaluate the responses of soluble sugars, starch, and TNSC (total nonstructural carbohydrates including both soluble sugars and starch) concentrations in different tree organs (leaf, stem, and root) to drought intensity and duration. We found that starch in all organs decreased and soluble sugars in leaf increased with prolonged experiment time, and the changes in soluble sugars in all organs were stronger under severe drought than under slight‐to‐moderate drought. Under slight‐to‐moderate drought, the NSC content of each organ varied with time, while with the extension of the drought duration, the NSCs gradually approached the control value (no drought stress); this trend remained in the late drought, which means that trees activated physiological regulation processes to increase carbon storage and reduce the risks of carbon starvation. In contrast, long‐term severe drought could lead to a net loss of carbohydrates, especially in the root, implying that prolonged severe drought could lead to NSC depletion in the whole plant. As prolonged drought duration has occurred in and is projected for many regions, this paper could shed light into studies on how trees respond and adapt extending drought duration through nonstructural carbon production, transportation, and reallocation.
Under slight‐to‐moderate drought, the NSC content of each organ varied with time, while with the extension of the drought duration, the NSCs gradually approached the control value (no drought stress); this trend remained in the late drought, which means that trees activated physiological regulation processes to increase carbon storage and reduce the risks of carbon starvation. In contrast, long‐term severe drought could lead to a net loss of carbohydrates, especially in the root, implying that prolonged severe drought could lead to NSC depletion in the whole plant.
Understanding spring phenology changes in response to the rapid climate change at biome‐level is crucial for projecting regional ecosystem carbon exchange and climate–biosphere interactions. In this ...study, we assessed the long‐term changes and responses to changing climate of the spring phenology in six temperate biomes of China by analyzing the global inventory monitoring and modeling studies (GIMMS) NOAA/AVHRR Normalized Difference Vegetation Index (NDVI) and concurrent mean temperature and precipitation data for 1982–2006. Results show that the spring phenology trends in the six temperate biomes are not continuous throughout the 25 year period. The spring phenology in most areas of the six biomes showed obvious advancing trends (ranging from −0.09 to −0.65 day/yr) during the 1980s and early 1990s, but has subsequently suffered consistently delaying trends (ranging from 0.22 to 1.22 day/yr). Changes in spring (February–April) temperature are the dominating factor governing the pattern of spring vegetation phenology in the temperate biomes of China. The recently delayed spring phenology in these temperate biomes has been mainly triggered by the stalling or reversal of the warming trend in spring temperatures. Results in this study also reveal that precipitation during November–January can explain 16.1% (P < 0.05), 20.9% (P < 0.05) and 14.2% (P < 0.05) of the variations in temperate deciduous forest (TDF), temperate steppe (TS), temperate desert (TD) respectively, highlighting the important role of winter precipitation in regulating changes in the spring vegetation phenology of water–limited biomes.
A system is proposed to generate vortex electromagnetic (EM) beams in the microwave band, which generates high-order vortex beams at the X-frequency band for the first time. First, the orbital ...angular momentum (OAM)-generating system is designed and the signal model based on the uniform circular array is presented. Subsequently, the mathematical model with array error contributions is established and, comprehensively, numerical simulations are conducted to analyze how amplitude and phase errors affect the radiation field and the EM vortex imaging. The experimental results validate that the proposed system can readily generate vortex beams of high quality, which are in agreement with the simulated results. The work paves the way to applications of OAM-carrying beams as well as a novel information-rich radar paradigm.
Public health is a priority for the Chinese Government. Evidence-based decision making for health at the province level in China, which is home to a fifth of the global population, is of paramount ...importance. This analysis uses data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 to help inform decision making and monitor progress on health at the province level.
We used the methods in GBD 2017 to analyse health patterns in the 34 province-level administrative units in China from 1990 to 2017. We estimated all-cause and cause-specific mortality, years of life lost (YLLs), years lived with disability (YLDs), disability-adjusted life-years (DALYs), summary exposure values (SEVs), and attributable risk. We compared the observed results with expected values estimated based on the Socio-demographic Index (SDI).
Stroke and ischaemic heart disease were the leading causes of death and DALYs at the national level in China in 2017. Age-standardised DALYs per 100 000 population decreased by 33·1% (95% uncertainty interval UI 29·8 to 37·4) for stroke and increased by 4·6% (–3·3 to 10·7) for ischaemic heart disease from 1990 to 2017. Age-standardised stroke, ischaemic heart disease, lung cancer, chronic obstructive pulmonary disease, and liver cancer were the five leading causes of YLLs in 2017. Musculoskeletal disorders, mental health disorders, and sense organ diseases were the three leading causes of YLDs in 2017, and high systolic blood pressure, smoking, high-sodium diet, and ambient particulate matter pollution were among the leading four risk factors contributing to deaths and DALYs. All provinces had higher than expected DALYs per 100 000 population for liver cancer, with the observed to expected ratio ranging from 2·04 to 6·88. The all-cause age-standardised DALYs per 100 000 population were lower than expected in all provinces in 2017, and among the top 20 level 3 causes were lower than expected for ischaemic heart disease, Alzheimer's disease, headache disorder, and low back pain. The largest percentage change at the national level in age-standardised SEVs among the top ten leading risk factors was in high body-mass index (185%, 95% UI 113·1 to 247·7), followed by ambient particulate matter pollution (88·5%, 66·4 to 116·4).
China has made substantial progress in reducing the burden of many diseases and disabilities. Strategies targeting chronic diseases, particularly in the elderly, should be prioritised in the expanding Chinese health-care system.
China National Key Research and Development Program and Bill & Melinda Gates Foundation.
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Food flavors of 2-isobutylthiazole (ITT) and 1-(1,3-Thiazol-2-yl)ethanone (TEO) for the corrosion inhibition of X65 steel in H2SO4 were studied by electrochemical methods, atomic ...force microscopy (AFM), scanning electron microscopy (SEM) and theoretical calculations. Electrochemical experiments show that ITT and TEO can effectively inhibit the corrosion of cathode and anode of X65 steel, and they are mixed-type corrosion inhibitors. Surface topography analysis (SEM and AFM) also visually demonstrate that ITT and TEO form an effective barrier film on the X65 steel surface to isolate the corrosive medium. Theoretical calculations profoundly explain the inhibition mechanism of ITT and TEO at the molecular level. In addition, the adsorption behavior of ITT and TEO on the surface of X65 steel is consistent with Langmuir isotherm adsorption. The results of experimental and theoretical studies have shown that the inhibition effect of TEO is better than ITT for X65 in 0.5 M H2SO4.
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