Investigation on the roles of equilibrium toroidal rotation during edge-localized mode mitigated by resonant magnetic perturbations

The effects of equilibrium toroidal rotation during edge-localized mode(ELM)mitigated by resonant magnetic perturbation(RMP)are studied with the experimental equilibria of the EAST tokamak based on the four-field model in the BOUT++code.As the two main parameters to determine the toroidal rotation profiles,the rotation shear and magnitudes were separately scanned to investigate their roles in the impact of RMPs on peeling-ballooning(P-B)modes.On one hand,the results show that strong toroidal rotation shear is favorable for the enhancement of the self-generated E×B shearing rate<ω_(E×B)>with RMPs,leading to significant ELM mitigation with RMP in the stronger toroidal rotation shear region.On the other hand,toroidal rotation magnitudes may affect ELM mitigation by changing the penetration of the RMPs,more precisely the resonant components.RMPs can lead to a reduction in the pedestal energy loss by enhancing the multimode coupling in the turbulence transport phase.The shielding effects on RMPs increase with the toroidal rotation magnitude,leading to the enhancement of the multimode coupling with RMPs to be significantly weakened.Hence,the reduction in pedestal energy loss by RMPs decreased with the rotation magnitude.In brief,the results show that toroidal rotation plays a dual role in ELM mitigation with RMP by changing the shielding effects of plasma by rotation magnitude and affecting<ω_(E×B)>by rotation shear.In the high toroidal rotation region,toroidal rotation shear is usually strong and hence plays a dominant role in the influence of RMP on P-B modes,whereas in the low rotation region,toroidal rotation shear is weak and has negligible impact on P-B modes,and the rotation magnitude plays a dominant role in the influence of RMPs on the P-B modes by changing the field penetration.Therefore,the dual role of toroidal rotation leads to stronger ELM mitigation with RMP,which may be achieved both in the low toroidal rotation region and the relatively high rotation region that has strong rotational shear.

甘肃中北部第一场透雨的气候特征及其相关因子分析

利用1957~2014年甘肃中北部4个台站逐日降水资料,分析了第一场透雨发生的气候特征及其影响因子。结果表明:第一场透雨出现日期在空间上从南向北推迟,区域性平均第一场透雨日期集中出现在5月,平均日期在5月中旬,也是出现频率最高的旬;区域性平均第一场透雨无显著的气候特征趋势,但有明显的年代际变化:1950年代末至1960年代初、1970年代中后期、1990年代初期至2000年代后期迟于6月以后;1960年代中期至1970前期、1980年代、2010年以后普遍偏早于4月下旬,有提前的趋势;透雨与春季降水有显著的负相关,透雨偏早,则春季降水偏多,特别是4月、5月降水偏多;前期1月亚洲中高纬500 hPa高度距平场呈“? + ?”、甘肃中北部经向风距平场出现偏南风,则透雨偏早,反之偏迟;上年5~7月大西洋中北部、欧洲中西部、西西伯利亚OLR增强(减弱),对应的甘肃中北部透雨偏迟(早);透雨的年际变化从南向北增大,均方差会宁26 d,靖远31 d,景泰35 d,白银41 d,这就决定了其预测难度大,稳定性差。

The effect of resonant magnetic perturbation with different poloidal mode numbers on peeling-ballooning modes

The effect of resonant magnetic perturbation(RMP)with different poloidal mode numbers on peeling-ballooning(P-B)modes is simulated with the BOUT++code.In order to investigate the physical mechanism of edge-localized mode mitigated by RMP,a series of RMPs with different poloidal mode numbers are applied into the four-field P-B mode simulation module separately.The results indicate that RMP has a better reducing effect on the energy loss from the pedestal when the resonant position is near the bottom and top of pedestal rather than near the middle.The RMP could influence P-B modes through the following effects:on the one hand,the E×B shearing rate is significantly stronger when the RMP(resonant surface locates at the top of the pedestal)is added,which can suppress the radial propagation of the negative pressure perturbation and reduce energy loss from the pedestal.On the other hand,the coupling of toroidal modes in the nonlinear phase is enhanced when RMPs are added,which motivated the growth of multiple toroidal modes,and the turbulence fluctuation level is weaker with the RMP when the resonant surface is located at the bottom of the pedestal.

Relationship analysis between September precipitation in western China and 700 hPa wind field in East Asia

The regional wind index influencing September precipitation in western China has been defined using the 700 hPa u and v components of NCAR/NCEP reanalysis data of 1961 to 2006. There are three regional wind field indices： southwest, southeast, and north, and these indices reflect the change of East Asian monsoon. The relationship between the indices was studied, and results show that they not only have a close relationship, but also have independence. Moreover, there is an obvious relationship between the wind indices and the autumn in particular the September precipitation in western China. The effect of wind indices on rain occurrence is most different： the influenced area of the southwest wind index is larger than that of the southeast wind index, and the southwest wind index is a controlling factor on autumn precipitation in western China. The weakening of southwest wind is the main cause resulting in reduction of autumn precipitation on the east side of the Tibetan Plateau.

Study on Genetic Toxicity of Solidago decurrens

[Objectives]This study was conducted to analyze the genetic toxicity of Solidago decurrens,with a view to scientifically and safely using S.decurrens.[Methods]Using commercially available S.decurrens as an experimental material,according to Vicia faba root tip micronucleus technique,V.faba root tips were treated with different doses of aqueous extract from S.decurrens for different times,and the mitotic index,frequency of micronucleus and chromosomal aberration of root tips in V.faba were detected,so as to reveal the allelopathic potential and the potential ecological risks of S.decurrens at the cellular level.[Results]The decrease in the mitotic index caused by the aqueous extract of S.decurrens was positively related to the concentration of the aqueous extract and the treatment time.The aqueous extract of S.decurrens increased the frequency of micronucleus in root tip cells of V.faba,and the increase was positively related to the concentration of the aqueous extract and the treatment time.The aqueous extract of S.decurrens caused abnormal phenomena such as chromosome bridges,chromosome fragmentation,and chromosome lag in V.faba root tip cells,and the effect of the aqueous extract on V.faba root tips had significant effects dependent on time and concentration.Above results indicate that the aqueous extract of S.decurrens inhibited and damaged the mitosis of V.faba root tip cells to some degrees,had certain genetic toxicity and had the ability to rapidly spread.[Conclusions]This study provides a theoretical basis for scientifically and rationally using S.decurrens and preventing the spread of S.decurrens.

Focusing characteristics of the relativistic electron beam transmitting in ion channel

Based on the beam-plasma system model established in this paper,the trajectory of the electron beam in the ion channel is studied quantitatively through the envelope equation.Under different initial system parameters,the focusing transmission conditions of the beam in the ion channel are discussed.Then,a series of particle-in-cell simulations are performed,which generally versifies the theoretical results and shows some further details of the focusing behavior of the beam.It is found that the deceleration of some electrons around the focusing point or the beam-plasma interaction at the ion channel boundary will result in the generation of the residual electrons,which forms the electron return current that leads to the new instabilities influencing the focusing characteristics of the beam.

Behavior of Phrynocephalus frontalis to Avoid Traps

Previous studies have shown that reptiles are capable of spatial learning and learn to locate important environmental resources so that they can return to those locations at a future time, when needed. Lizards improve their adaptability and survival by learning the position of their shelter in a complex environment. This behavior raises the question, whether lizards can sense danger, such as a trap, in their surroundings, by determining the location of the trap and avoiding it. In the present study, we used a pitfall trap to test if steppe toad-headed agama, Phrynocephalus frontalis, can learn to recognize the position of the trap and avoid it. Our results revealed that the percentage of activity time in the trap area was significantly reduced （P 〈 0.001） and the time of drop trap was also significantly reduced （P = 0.00631）. The number of burrows dug by lizards distributed in the trap area was the least. Reduced activity time in the trap area was observed to have no obvious relationship with the drop in the number of burrows. The present study, therefore, demonstrates that P. frontalis are capable of learning the avoidance of a trap by locating its position. The findings offer significant insight in the understanding of reptilian behavior, which is important in the study of the role of reptiles in global ecology, especially because they are often very sensitive to environmental changes.

Short-term metal accumulation and MTLP induction in the digestive glands of Perna virdis exposed to Zn and Cd

Time-dependent Zn and Cd accumulation and metallothionein like protein （MTLP） induction in the digestive glands of mussels, Perna virdis, were measured under different exposure conditions. The initial uptake rate at start of chase （ρ0） and mean residence time （τ） were calculated to determine the physiological response of organisms and their potential detoxification mechanisms. It was found that in digestive glands, Zn had obviously higher ρ0 and shorter mean residence time than Cd, indicating that these two metals had different accumulation dynamics even though they were very close in the periodic element table. MTLP levels in digestive glands varied from 0.51 to 1.05 μg/g ww （wet weight）. The MTLP level increased continuously when mussels were exposed to low and middle levels of Zn and Cd media, and reached maximal levels at day 4, then decreased when they were exposed to high level Zn and Cd solutions. With regard to the fraction of Zn and Cd accumulated in the digestive glands, the ratios of soluble metal to total metal decreased continuously after exposure in low and middle levels of Zn and Cd media, and decreased continuously in the first 4 days and then to level off when mussels were exposed to media with high concentration of Zn and Cd. Results suggested that both MTLP induction and metal insolubilization were detoxification processes in digestive glands of mussels.

Simulating androgen receptor selection in designer yeast

Androgen receptor(AR)mutation is closely associated with prostate cancer(PCa)and is one of the mechanisms of resistance to PCa therapies such as AR antagonists.Although sequencing technologies like next-generation sequencing(NGS)contributes to the high-throughput and precise detection of AR mutations carried by PCa patients,the lack of interpretations of these clinical genetic variants has still been a roadblock for PCa-targeted precision medicine.Here,we established a designer yeast reporter assay to simulate natural androgen receptor(AR)selection using AR antagonists.Yeast HIS3 gene transactivation was associated with the ligand-induced recruitment of steroid receptor coactivator-1(SRC-1)by AR mutants,where yeast growth in histidine-free medium was determined as the outcome.This assay is applicable to determine a wide range of clinical AR mutants including those with loss of function relating to androgen insensitivity syndrome(AIS),and those associated with PCa conferring resistance to AR antagonists such as enzalutamide(ENZ),bicalutamide(BIC),and cyproterone acetate(CPA).One clinical AR mutant previously reported to confer ENZ-resistance,F877L,was found to confer partial resistance to CPA as well using designer yeast.Our simple and efficient assay can enable precise one-pot screening of AR mutants,providing a reference for tailored medicine.

Influence of Poloidal Rotation of Plasma on Peeling-Ballooning Modes

Influence of the poloidal rotation of the plasma on Peeling-Ballooning modes(P-B modes)is studied with BOUT++code.The results show that the poloidal rotation destabilizes P-B modes because of the effect of Kelvin-Helmholtz instability when the poloidal rotation is large enough and the shear is small,and the shear of the poloidal rotation can stabilize high-n P-B modes when the shear is increased.

预制冷站技术在数据中心的应用研究

我国数据中心建设近年来蓬勃发展,如何快速、高效、高质量建设数据中心成为了目前亟待解决的问题,衣文针对两种预制冷站形式进行方案介绍,分别对其在&据中心应用中的特点、工期、经济性、施工工艺等问题进行研究分析,最后给出了两种冷站的应用建议。