Gate-controllable spin-battery

We propose a gate-controllable spin-battery for spin current. The spin-battery consists of a lateral double quantum dot under a uniform magnetic field. A finite DC spin-current is driven out of the device by controlling a set of gate voltages. Spin-current can also be delivered in the absence of charge-current. The proposed device should be realizable using present technology at low temperature.Comment: 3 pages, 3 figures, accepted by Appl. Phys. Let

Search for stochastic gravitational-wave background from string cosmology with Advanced LIGO and Virgo's O1∼\simO3 data

String cosmology models predict a relic background of gravitational-wave (GW) radiation in the early universe. The GW energy spectrum of radiated power increases rapidly with the frequency, and therefore it becomes a potential and meaningful observation object for high-frequency GW detector. We focus on the stochastic background generated by superinflation in string theory and search for such signal in the observing data of Advanced LIGO and Virgo O1$\sim$O3 runs in a Bayesian framework. We do not find the existence of the signal, and thus put constraints on the GW energy density. Our results indicate that at $f=100\,\text{Hz}$, the fractional energy density of GW background is less than $1.7\times10^{-8}$ and $2.1\times10^{-8}$ for dilaton-string and dilaton only cases respectively, and further rule out the parameter space restricted by the model itself due to the non-decreasing dilaton and stable cosmology background ($\beta$ bound).Comment: Accepted by Journal of Cosmology and Astroparticle Physic

Does ISO 9000 certification benefit service firms?

This paper examines whether ISO 9000 certification benefits service firms in terms of their financial performance and promotes sustainable improvement. We argue that in a developing country setting such as China, the massive benefits brought by the signalling effect of the certification can discourage firms' motivation to fully implement the standard of certification and lead to the decline of investment on productivity-improving activities. In other words, the certification may have negative effects on the productivity of certified firms. We investigate 89,024 firms in Chinese service industries to assess the impacts of the certification on sales, productivity and profitability of these firms. To address the potential selection bias of ISO 9000 certification, the Propensity Score Matching method and Coarsened Exact Matching method were used. Our key findings are that the ISO 9000 certification does help to increase the total amount of sales, but it decreases the productivity and profitability of these certified service firms. We also find that earlier certifiers seem to gain larger advantage in sales but more reduction in productivity, and firms with higher level of technology intensity seem to obtain a larger increase in sales and less productivity loss after receiving their ISO 9000 certification

Isolation and characterization of 13 new microsatellite markers in the triangle mussel (Hyriopsis cumingii)

Microsatellite enriched library of Hyriopsis cumingii was constructed according to the strong affinity between biotin and streptavidin. One hundred clones with foreign inserts were sequenced and 65 clones were screened for usable microsatellites, of which 36 were deemed unique, of sufficient length (more than 8 repeats) and possessed adequate flanking regions for primer designment. Among 36 primer pairs designed, 25 yielded scorable amplification products. Upon testing 30 individuals were sampled using the 25 pair primers from Dongting Lake of Hunan Province, China. Then thirteen polymorphic microsatellite markers were isolated and characterized. These loci exhibited high levels of genetic polymorphism, so the observed number of alleles per locus ranged from 4 to 9. The ranges of observed and expected heterozygosity were 0.2543 to 0.8913 and 0.3629 to 0.8217, respectively, and the average polymorphic information content was 0.5198. Two microsatellite loci were significantly deviated from Hardy-Weinberg equilibrium due to the presence of null alleles, and no linkage disequilibrium found. These microsatellite loci will be useful for assessing the genetic diversity and population structure of H. cumingii

Dynamical encircling exceptional point in largely detuned multimode optomechanical system

Dynamical encircling exceptional point(EP) shows a number of intriguing physical phenomena and its potential applications. To enrich the manipulations of optical systems in experiment, here, we study the dynamical encircling EP, i.e. state transfer process, in largely detuned multimode optomechanical system. The process of state transfer has been investigated with different factors about the location of start point, the orientation and the initial state of the trajectories around the EP in parameter space. Results show that the nonreciprocal and the chiral topological energy transfer between two optical modes are performed successfully by tuning the effective optomechanical coupling in the multimode system with large detuning. Moreover, the factor of evolution speed about system parameters is also discussed. Our work demonstrates the fundamental physics around EP in large detuning domain of multimode optomechanical system and provides an alternative for manipulating of optical modes in non-hermitian system.Comment: 9 pages,7 figure

Assessing the effectiveness of complex dietary candidate probiotics on growth performance, digestive enzyme activity, antioxidant capability, and intestinal microbiota of koi carp (Cyprinus carpio var. koi)

The present study aimed to evaluate the effectiveness of three complex dietary candidate probiotics (LDJ, LAC, and LJD) composing different candidate probiotic combinations on the growth performance, digestive enzyme activities, antioxidant parameters, and intestinal microbiota in koi carp (Cyprinus carpio var. koi). After a 60-days feeding trial, samples from the control and three candidate probiotic groups were obtained and analyzed. The results suggested that all complex dietary candidate probiotic treatments (LDJ, LAC, and LJD) improved the growth performance, nutrition utilization, and intestinal digestive enzyme activities compared with the control group. Furthermore, a dietary supplement with LAC or LJD is more efficient in growth and digestive enzyme than LDJ. The antioxidant enzyme activities, including SOD (superoxide dismutase), CAT (catalase), and GPX (glutathione peroxidase), were intensively improved, the GSH (glutathione) contents increased, and the MDA (malondialdehyde) contents decreased to different extents depending on the tissues and kinds of candidate probiotics. Dietary candidate probiotics also regulated the intestinal microbiota composition: LDJ and LAC increased the proportion of potential candidate probiotics and reduced the level of pollutants reducing bacteria and geosmin producer Nannocystis. The LJD group had a similar pattern of the dominant bacteria to the control sample, suggesting a minor disturbance of the gut microbiota of koi carp. Overall, the multi-strain complex candidate probiotics LAC and LJD are more efficient in growth performance and digestive enzymes

Enhanced sensing mechanism based on shifting an exceptional point

Non-Hermitian systems associated with exceptional points (EPs) are expected to demonstrate a giant response enhancement for various sensors. The widely investigated enhancement mechanism based on diverging from an EP should destroy the EP and further limits its applications for multiple sensing scenarios in a time sequence. To break the above limit, here we proposed a new enhanced sensing mechanism based on shifting an EP. Different from the mechanism of diverging from an EP, our scheme is an EP non-demolition and the giant enhancement of response is acquired by a slight shift of the EP along the parameter axis induced by perturbation. The new sensing mechanism can promise the most ffective response enhancement for all sensors in the case of multiple sensing in a time sequence. To verify our sensing mechanism, we construct a mass sensor and a gyroscope with concrete physical implementations. Our work will deepen the understanding of EP-based sensing and inspire designing various high sensitivity sensors in different physical systems.Comment: 7 pages, 3 figure