Heat distribution in quantum Brownian motion.

We investigate the heat statistics in a relaxation process of quantum Brownian motion described by the Caldeira-Leggett model. By employing the normal mode transformation and the phase-space formulation approach, we can analyze the quantum heat distribution within an exactly dynamical framework beyond the traditional paradigm of Born-Markovian and weak-coupling approximations. It is revealed that the exchange fluctuation theorem for quantum heat generally breaks down in the strongly non-Markovian regime. Our results may improve the understanding about the nonequilibrium thermodynamics of open quantum systems when the usual Markovian treatment is no longer appropriate.

[Effect of Biochar with Phosphorus Fertilizer on Soil Nutrients, Enzyme Activity, and Nutrient Uptake of Alfalfa].

Biochar is widely used in agricultural production practices as a soil conditioner that can be used both alone and jointly with chemical fertilizer. However, there are few studies on the effects of the combined application of biochar and phosphate fertilizer with different particle sizes on soil and plants. In this experiment, pot experiments were used to study the effects of biochar with different particle sizes on soil nutrients, enzyme activity, and Alfalfa nutrient absorption under two phosphorus levels (according to diameter, the biochar was divided into C1:>1 mm and C2:<0.01 mm). This study showed that the combined application of biochar and phosphorus significantly improved soil nutrients, enzyme activity, and Alfalfa nutrient absorption. Among them, the C2 treatment significantly increased the soil available phosphorus content and phosphatase activity (P<0.05), whereas the C1 treatment had a significant effect on ammonium nitrogen, nitrate nitrogen, urease, and catalase activities (P<0.05). Moreover, the differences in nutrients and enzymes among biochar treatments with different particle sizes were affected by soil phosphorus levels. At the P0 level, there was no significant difference in ammonium nitrogen and nitrate nitrogen contents between the C1 and C2 treatments. At the P1 level, the contents of NH4+-N and NO3--N in the C1 treatment were 24.19% and 18.68% higher than those in the C2 treatment (P<0.05), but there was no significant difference between the C1 and C2 treatments. Phosphorus addition significantly increased the N and P contents of Alfalfa above ground and in the ground (P<0.05), but there was no significant effect on the nutrient content of Alfalfa between different particle sizes of biochar. In conclusion, biochar and phosphate fertilizer can be used as an effective means of soil improvement. In addition, when using biochar for soil improvement, the impact of particle size on soil nutrients and soil enzymes should be considered.

Work statistics and thermal phase transitions.

Many previous studies have demonstrated that work statistics can exhibit certain singular behaviors in the quantum critical regimes of many-body systems at zero or very low temperatures. However, as the temperature increases, it is commonly believed that such singularities will vanish. Contrary to this common recognition, we report a nonanalytic behavior of the averaged work done, which occurs at finite temperature, in the Dicke model as well as the Lipkin-Meshkov-Glick model subjected to the sudden quenches of their work parameters. It is revealed that work statistics can be viewed as a signature of the thermal phase transition when the quenched parameters are tuned across the critical line that separates two different thermal phases.

[Effects of exogenous melatonin on antioxidant capacity and nutrient uptake of Lolium perenne and Medicago sativa under drought stress]. / å¤–æºè¤ªé»‘ç´ å¯¹å¹²æ—±èƒè¿«ä¸‹é»‘éº¦è‰å’Œè‹œè“¿æŠ—æ°§åŒ–èƒ½åŠ›åŠå »åˆ†å¸æ”¶çš„å½±å“.

To explore the effects of exogenous melatonin on antioxidant capacity and nutrient uptake of plants under drought stress, we used Lolium perenne and Medicago sativa potted seedlings for foliar spraying and root application of 100 µmol·L-1 melatonin, respectively. We measured the biomass, malondialdehyde (MDA) content, relative conductivity, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities, as well as nutrient contents (organic carbon, total nitrogen, total phosphorus) under drought stress. The results showed that the biomass of L. perenne and M. sativa decreased significantly under drought stress, and that external melatonin application could effectively alleviate the inhibitory effect of drought stress on L. perenne and M. sativa. Foliar spray and root application of melatonin under drought stress enhanced L. perenne biomass by 14.5% and 29.6%, and that of M. sativa by 36.6% and 49.1%, respectively. The SOD and POD activities in L. perenne and SOD activity in M. sativa significantly decreased under drought stress, and exogenous melatonin significantly increased SOD, POD and CAT activities in L. perenne and M. sativa, reduced the accumulation of MDA in leaves, caused a significant decrease in the relative conductivity of leaves, and significantly increased antioxidant capacity. Drought stress and exogenous melatonin did not affect organic carbon content of L. perenne and M. sativa. Under drought stress, the contents of N and P in L. perenne leaves and roots and the content of N in M. sativa roots decreased, while the application of melatonin increased the contents of N and P in roots and leaves of L. perenne and M. sativa, indicating that melatonin could regulate the nutrient absorption of L. perenne and M. sativa under drought stress. In conclusion, the melatonin application not only improved the antioxidant capacity of plants, but also regulated nutrient uptake to enhance plant resilience to drought stress. Foliar spraying of melatonin was more effective than root application.

Controllable dynamics of a dissipative two-level system.

We propose a strategy to modulate the decoherence dynamics of a two-level system, which interacts with a dissipative bosonic environment, by introducing an ancillary degree of freedom. It is revealed that the decay rate of the two-level system can be significantly suppressed under suitable steers of the assisted degree of freedom. Our result provides an alternative way to fight against decoherence and realize a controllable quantum dissipative dynamics.

[Polycyclic Aromatic Hydrocarbons in the Atmosphere of Dajiuhu, Shennongjia, China].

The concentration, potential source and health risks of 16 polycyclic aromatic hydrocarbons (PAHs) in the atmosphere of Dajiuhu, Shennongjia, China, were studied. Polyurethane foam (PUF) Passive air samplers (PAS) were settled. The results indicated that the total concentrations of 16 PAHs in different samples ranged from 6.94 to 184.23 ng·m-3, with the mean of 30.36 ng·m-3. The dominant compounds were low rings PAHs, such as Phe, Nap, Pyr, Fla, Flu and Ant. Compared with other regions, the PAHs pollution of Dajiuhu atmosphere was at a low level. Higher PAHs concentrations were detected in nearby Deer farm, Dajiuhu peat area and Dajiuhu Wetland Authority. Higher PAHs concentrations were detected in autumn and winter, whereas lower concentrations were detected in spring and summer. Potential pollution sources of PAHs were investigated by diagnostic ratios and backward trajectory analysis, which indicated that coal and biofuel combustion, vehicle emissions and petroleum were the main sources. PAHs of Dajiuhu in air not only came from local emission, but also originated from Hubei, Henan and Hunan's atmosphere transport for most part and long range transport from northwest direction for small part. Health risks assessment results showed that the annual average concentration of total Benzo(a)pyrene-equivalent carcinogenic potency (∑BaPeq) was 0.208 ng·m-3, lower than the value recommended by Ambient Air Quality Standard of China(GB 3095-2012, 1 ng·m-3), indicating a low carcinogenic risk for the local residents.

Polycyclic aromatic hydrocarbons (PAHs) in multimedia environment of Heshan coal district, Guangxi: distribution, source diagnosis and health risk assessment.

Mining activities are among the major culprits of the wide occurrences of soil and water pollution by PAHs in coal district, which have resulted in ecological fragilities and health risk for local residents. Sixteen PAHs in multimedia environment from the Heshan coal district of Guangxi, South China, were measured, aiming to investigate the contamination level, distribution and possible sources and to estimate the potential health risks of PAHs. The average concentrations of 16 PAHs in the coal, coal gangue, soil, surface water and groundwater were 5114.56, 4551.10, 1280.12 ng g(-1), 426.98 and 381.20 ng L(-1), respectively. Additionally, higher soil and water PAH concentrations were detected in the vicinities of coal or coal gangue dump. Composition analysis, isomeric ratio, Pearson correlation analysis and principal component analysis were performed to diagnose the potential sources of PAHs in different environmental matrices, suggesting the dominant inputs of PAHs from coal/coal combustion and coal gangue in the soil and water. Soil and water guidelines and the incremental lifetime risk (ICLR) were used to assess the health risk, showing that soil and water were heavily contaminated by PAHs, and mean ICLRcoal/coal-gangue and mean ICLRsoil were both significantly higher than the acceptable levels (1 × 10(-4)), posing high potential carcinogenic risk to residents, especially coal workers. This study highlights the environmental pollution problems and public health concerns of coal mining, particularly the potential occupational health hazards of coal miners exposed in Heshan.

[Distribution and enrichment characteristics of organochlorine pesticides in water and halobios from Qingbang Island in Zhoushan, China].

A total of 14 biological samples and 3 water samples were collected from the Qingbang Island. The concentrations of OCPs in the samples were determined by GC-ECD to investigate the distribution, composition, source and potential health risks of these compounds in the study area. The results showed that OCPs were detected in all samples. The detection ratios of OCPs were 100%. Concentrations of HCHs and DDTs ranged from 0.09 ng x g(-1) to 11.51 ng x g(-1) and 0. 02 ng x g(-1) to 56.15 ng x g(-1), respectively. Compared with other regions, the pollution of OCPs in Qingbang Island stayed at a low level. Distribution characteristics of OCPs in halobios from Qingbang Island indicated that changes in the upwelling and fronts were the main factors that affected the distribution of OCPs. Source analysis showed that HCHs and DDTs in halobios were mainly originated from the external. In addition, OCPs residues were far below the National Food Safety Standard. The estimated daily intake of OCPs from the halobios tested was also below the acceptable daily intake(ADI) recommended by FAO/WHO, indicating little health risk in halobios consumption for local residents.