Anomalous supercurrent modulated by interfacial magnetizations in Josephson junctions with ferromagnetic bilayers

Based on the Bogoliubov-de Gennes equations, we investigate the transport of the Josephson current in a S/$f_L$-F$_1$-$f_C$-F$_2$-$f_R$/S junction, where S and F$_{1,2}$ are superconductors and ferromagnets, and $f_{L, C, R}$ are the left, central, and right spin-active interfaces. These interfaces have noncollinear magnetizations, and the azimuthal angles of the magnetizations at the $f_{L, C, R}$ interfaces are $\chi_{L, C, R}$. We demonstrate that, if both the ferromagnets have antiparallel magnetizations, the critical current oscillates as a function of the exchange field and the thickness of the ferromagnets for particular $\chi_L$ or $\chi_R$. By contrast, when the magnetization at the $f_C$ interface is perpendicular to that at the $f_L$ and $f_R$ interfaces, the critical current reaches a larger value and is hardly affected by the exchange field and the thickness. Interestingly, if both the ferromagnets are converted to antiparallel half-metals, the critical current maintains a constant value and rarely changes with the ferromagnetic thicknesses and the azimuthal angles. At this time, an anomalous supercurrent can appear in the system, in which case the Josephson current still exists even if the superconducting phase difference $\phi$ is zero. This supercurrent satisfies the current-phase relation $I=I_c\sin(\phi+\phi_0)$ with $I_c$ being the critical current and $\phi_0=2\chi_C-\chi_L-\chi_R$. We deduce that the additional phase $\phi_0$ arises from phase superposition, where the phase is captured by the spin-triplet pairs when they pass through each spin-active interface. In addition, when both the ferromagnets are transformed into parallel half-metals, the $f_C$ interface never contributes any phase to the supercurrent and $\phi_0=\chi_R-\chi_L+\pi$. In such a case, the current-phase relation is similar to that in a S/$f_L$-F-$f_R$/S junction

Prevention and Control of Agricultural Non-Point Source Pollutions in UK and Suggestions to China

Currently, the world is facing challenges of maintaining food production growth while improving agricultural ecological environmental quality. The prevention and control of agricultural non-point source pollution, a key component of these challenges, is a systematic program which integrates many factors such as technology and its extension, relevant regulation and policies. In the project of UK-China Sustainable Agriculture Innovation Network, we undertook a comprehensive analysis of the prevention and control technology, technology extension systems and related policy measures of agricultural non-point source pollution in UK. We then proposed the promotion of prevention and control of agricultural non-point source pollution in China. Considering the current agricultural resources and environment countermeasures of “one control”(control over the total quantity of the agricultural water and agricultural water environment pollution), “two reduction”(reduction in quantities of fertilizers and pesticides), and “three basic countermeasures”(resource utilization, recycling, and mitigate harm from treatment of livestock and poultry wastes, agricultural plastic films and crop straws), we suggested that in the near future source control and process prevention should be technical priorities. Optimization and reduction of chemical fertilizer, combined use of chemical and organic fertilizers, land utilization management, agricultural sector adjustment and integration of crop production with animal husbandry should be the key technologies. The role of non-governmental technical service should be promoted. Government subsidies, ecological compensations and other forms of economic means could be used to encourage famers actively participate in the prevention and control of nitrogen and phosphorus losses and pollution in soil and water systems. Related technical documents and regulations should be more specific, clear, and practical. Collection, transmission and analysis of non-point source pollution data relying on modern information approaches should also be incorporated in the non-point source control projects. The prevention and control of non-point source pollution from agriculture should be integrated into the overall national economic and social development planning, and be unified with the industry optimization and economic development indicators to improve the quality of ecological civilization construction, aiming at the sustainable economic and social development in China

Biološka karakterizacija izolata golubljeg paramiksovirusa 1 i analiza njegove patogenosti u SPF pilića

Pigeon paramyxovirus type 1 (PPMV-1) is considered as an antigenic variant of Newcastle Disease leading to high mortality and significant economic losses to the poultry industry. However, the pathogenicity of PPMV-1 to chickens is still unclear. Herein, we reported the biological characterization of the isolated PPMV-1 from the diseased pigeons suspected to Newcastle Disease and studied its pathogenicity in SPF chickens. The phylogenetic tree and evolution distances revealed that the new isolate belonged to a VI.2.1.1.2.2 sub-genotype of NDV. Despite the cleavage motif of the F protein containing the 112RRQKR↓F117 sequence associated with virulent NDV strains, and the value of MDT and ICPI of the isolate showing mesogenic characteristics, the challenge trial showed that the isolate had weak pathogenicity to chickens while causing lesions in multiple tissues and organs in pigeons.Golublji paramiksovirus tipa 1 (PPMV-1) smatra se antigenskom varijantom njukaslske bolesti koja uzrokuje visoku smrtnost i znatne ekonomske gubitke u peradarskoj industriji. Patogenost virusa PPMV-1 u pilića međutim još uvijek nije jasna. U ovom je radu provedena biološka karakterizacija PPMV-1 izoliranog iz golubova za koje se sumnja da su oboljeli od njukaslske bolesti te je istražena njihova patogenost u SPF pilića. Filogenetsko stablo i evolucijske udaljenosti otkrili su da novi izolat pripada podgenotipu VI.2.1.1.2.2 virusa njukaslske bolesti (NDV). Unatoč motivu u mjestu cijepanja F-proteina koji sadržava sekvenciju 112RRQKR↓F117 povezanu s virulentnim sojevima NDV-a, vrijednosti MDT-a i ICPI-ja izolata pokazale su mezogene značajke. Ovo probno istraživanje je pokazalo da su izolati PPMV-1 slabo patogeni u pilića, dok u golubova uzrokuju lezije na više organa i tkiva

Research on sound radiation characteristics of the high-speed train wheel

Taking the standard wheel model as an example, the radiation noise of a single wheel under excitation force which is computed by multi-body dynamics model is computed by acoustic boundary element method (BEM). Then, the damped wheel is proposed, and the sound radiation characteristics of both wheels are analyzed and compared. The results show that sound field of a single wheel presents an obvious directivity with petaloid change and continuous decrease, and the wheel tread and web contribute the most rolling noise. Compared with the standard wheel, the acoustic radiation power of the damped wheel decreased significantly, especially at the peak frequency. After that, the radiation noise generated by the wheel in the train is researched. The results show that the radiation noise generated by the wheel in the train is a complex sound field after the superposition and interference of multiple wheel noises, which are mainly in the bogies at both ends and its vicinity region. Meanwhile, the basic directivity characteristics of the petaloid change and continuous reduction are remained. The radiation noise which is generated by the wheel in the train has obvious peak characteristic, whose corresponding peak noises are below 110 dB. The radiation noise of the damped wheel is significantly smaller than that of the standard wheel at most frequency bands, and the total SPL at the observation point has decreased by 14.5 dB with obvious noise reduction effect. In order to further research the radiation noise of the damping wheel, influence factors on the noise reduction are analyzed. Finally, these parameters such as thickness and material should be considered comprehensively during designing the damping wheel, in order to find the optimal combination of all parameters

Birkhoff's Theorem in f(T) Gravity up to the Perturbative Order

f(T) gravity, a generally modified teleparallel gravity, has become very popular in recent times as it is able to reproduce the unification of inflation and late-time acceleration without the need of a dark energy component or an inflation field. In this present work, we investigate specifically the range of validity of Birkhoff's theorem with the general tetrad field via perturbative approach. At zero order, Birkhoff's theorem is valid and the solution is the well known Schwarzschild-(A)dS metric. Then considering the special case of the diagonal tetrad field, we present a new spherically symmetric solution in the frame of f(T) gravity up to the perturbative order. The results with the diagonal tetrad field satisfy the physical equivalence between the Jordan and the so-called Einstein frames, which are realized via conformal transformation, at least up to the first perturbative order.Comment: 8 pages, no figure. Final version, accepted for publication in EPJ

Air pollution reduction and climate co-benefits in China's industries

Air pollution reduction policies can simultaneously mitigate CO_{2} emissions in the industrial sector, but the extent of these co-benefits is understudied. We analyse the potential co-benefits for SO_{2}, NO_{x}, particulate matter (PM) and CO2 emission reduction in major industrial sectors in China. We construct and analyse a firm-level database covering nearly 80,000 observations and use scenario simulations to estimate the co-benefits. The findings show that substantial co-benefits could be achieved with three specific interventions. Energy intensity improvement can reduce SO_{2}, NO_{x}, PM and CO_{2} emissions for non-power sectors by 26–44%, 19–44%, 25–46% and 18–50%, respectively. Reductions from scale structure adjustment such as phasing out small firms and developing large ones can amount to 1–8%, 1–6%, 2–20% and 0.2–3%. Electrification can reduce emissions by 19–25%, 4–28%, 20–29% and 11–12% if the share of electricity generated from non-fossil fuel sources is 70%. Since firm heterogeneity is essential to realize the co-benefits and directly determines the magnitudes of these benefits, stricter and sensible environmental policies targeting industrial firms can accelerate China’s sustainable transformation