SUMMARY
At 04:14:45 UT on 2022 January 15, a powerful eruption of the submarine Hunga Tonga–Hunga Ha'apai volcano occurred at about 30 km south of the Ha'apai Islands in the Kingdom of Tonga (at ...−20.55° N, −175.39° E). This eruption caused atmospheric waves that spread worldwide. In this study, we investigate the the total electron content (TEC) variation over China using the BeiDou Navigation Satellite System. The particularly interesting feature of the data set compared to other ground-based TEC data is the exclusive use of the BeiDou geostationary satellites, which monitor the TEC variations for fixed ionospheric piercing points and can provide more accurate calculations of the travelling speed of the disturbance. For comparison, atmospheric pressure records were examined, which show that the Lamb wave passed by the same stations four times with a constant speed of 310 m s−1. However, the TEC results show that the ionospheric disturbances passing over China four times with different speeds within four days after the eruption, two travelling along the short-path direction and two along the long-path direction. The primary front of the first short-path event travels with a speed of 340 m s−1, which is higher than the Lamb wave. The faster speed suggests that the primary front cannot be fully attributed to the Lamb wave, and further studies need to explore its mechanism. The second short-path and first long-path events travel with speeds of 301 and 310 m s−1, respectively, close to the speed of the Lamb wave, and they may be caused by upward energy leakage during the propagation of the Lamb wave. The second long-path event travels with a speed of 264 m s−1, possibly induced by the gravity waves.
Many blackouts in electric power grids throughout the world are caused by cascading outages, which often involve complex processes in various timescales. The multi-timescale nature of cascading ...outages makes conventional quasi-static simulation methods inaccurate in characterizing actual evolution of outages. This paper proposes a multi-timescale cascading outage model using a quasi-dynamic simulation method. The model establishes a framework for simulating interactions among dynamics in quite different timescales. It realizes simulation of cascading outages with representation of time evolution, so it overcomes ambiguity of time in conventional cascading outage models and hence has better practicality. Moreover, the model considers dynamics, e.g., load variation and generator excitation protection which affect voltage and reactive power profiles. Also, an improved re-dispatch model based on sensitivity is proposed. These improvements facilitate better simulation for a realistic power system. Also, dynamic simulation can be flexibly incorporated into the simulation of short-term processes in this model as needed. Case studies with the proposed multi-timescale model on the IEEE 30-bus system discuss the role of generator protection in cascading outage evolution, and analyze stage characteristics in outages. The multi-timescale model is also demonstrated on a reduced 410-bus US-Canada northeast power grid. Moreover, impacts from dispatchers' involvements are analyzed .
The VLF-induced ionospheric heating events from the powerful transmitter NWC are collected at extremely low solar activity years of 2008–2009, and their spatial and temporal distribution features are ...investigated. The spatial distribution of heating signals exhibits clear north-direction inclination of 2–3°, and covering area within 300 km radius in longitude and latitude. Plasma parameters show the obvious negative correlations between decreasing
N
e
and increasing
T
e
, and positive correlations of the increasing ion density and ion temperature during the VLF heating time. The ions move upwards to cause the perturbations in ULF electric field due to
V
⇀
×
B
⇀
.
The VLF heating events easily occur at seasons with low plasma density, which illustrates that low plasma environment plays an important role in VLF-induced ionospheric heating. Typical three enhanced VLF signals are obtained, one at 19.8 kHz with the largest amplitude, one at the broadened frequency band of 19.8 ± 300 Hz with one order of amplitude decreasing, and one between 19.5 kHz and lower hybrid frequency with at least two orders of amplitude reductions relative to that at 19.8 kHz but still one order increasing relative to non-heating region. These quasi electrostatic waves during VLF heating may not be from the VLF whistler conversion, but the lightning-whistler waves are enhanced when they pass through the plasma cavity formed during VLF heating process.
Key points
The heating region with radius of 2–3° has been detected over NWC transmitter.
Ions moved upwards over the heating region with clear decreasing
N
e
and increasing
T
e
.
Ultra-low frequency electric field was detected due to the effects of
V
⇀
×
B
⇀
.
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FFLJ, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, UL, UM, UPUK
As the observation accuracy of parameters in the ionosphere cannot be directly checked, the comparison with other observations is the main way to evaluate the data quality of satellite measurements. ...Through the comparative analysis between the in situ electron density (Ne) observed by the China Seismo-Electromagnetic Satellite (CSES) and Ne at about 500 km altitude detected by Qujing Incoherent Scatter Radar (ISR), it was found that the pattern of CSES Ne is consistent with that of ISR Ne, and the correlation coefficient between the two sets of data is above 0.88 for different groups according to the magnitude. The value of CSES Ne is lower than that of ISR Ne, and the median value of the ratio for the difference between the conjugate data is 84.04%. Based on the comparison in the daytime between CSES Ne and ionosonde observations in China, it was found that the trend of the two datasets is mostly similar, and the correlation coefficient in some locations can reach up to 0.7. The distribution of CSES Ne and correlation coefficients at different latitudes show that the relationship is relatively better around the peak of the equatorial ionization anomaly (EIA). The differences in the value between CSES Ne and ionosonde data also exist, the relative change of which is about 80–95% in the daytime.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Abstract
Contemporary climatic stress seriously affects rice production. Unfortunately, long-term domestication and improvement modified the phytohormones network to achieve the production needs of ...cultivated rice, thus leading to a decrease in adaptation. Here, we identify a 14-3-3 protein-coding gene
OsGF14h
in weedy rice that confers anaerobic germination and anaerobic seedling development tolerance.
OsGF14h
acts as a signal switch to balance ABA signaling and GA biosynthesis by interacting with the transcription factors OsHOX3 and OsVP1, thereby boosting the seeding rate from 13.5% to 60.5% for anaerobic sensitive variety under flooded direct-seeded conditions. Meanwhile,
OsGF14h
co-inheritance with the
Rc
(red pericarp gene) promotes divergence between temperate
japonica
cultivated rice and temperate
japonica
weedy rice through artificial and natural selection. Our study retrieves a superior allele that has been lost during modern
japonica
rice improvement and provides a fine-tuning tool to improve flood adaptation for elite rice varieties.
In the risk assessment of cascading outages, the rationality of simulation and efficiency of computation are both of great significance. To overcome the drawback of sampling-based methods that huge ...computation resources are required and the shortcoming of initial contingency selection practices that the dependencies in sequences of outages are omitted, this paper proposes a novel risk assessment approach by searching on Markovian Tree. The Markovian tree model is reformulated from the quasi-dynamic multitimescale simulation model proposed recently to ensure reasonable modeling and simulation of cascading outages. Then, a tree search scheme is established to avoid duplicated simulations on same cascade paths, significantly saving the computation time. To accelerate the convergence of a risk assessment, a risk estimation index is proposed to guide the search for states with major contributions to the risk, and the risk assessment is realized based on the risk estimation index with a forward tree search and backward update algorithm. The effectiveness of the proposed method is illustrated on a four-node power system, and its convergence profile as well as efficiency is demonstrated on the RTS-96 test system.
Heavy and medium plate (HMP) is a valuable and irreplaceable material that is widely used in pipelines, bridges, ships, building construction, and power plants. The quality of a plate’s surface is ...closely related to its strength, hardness, and corrosion resistance. HMP is still trimming to length after the continuous casting process. The goal of this research is to evaluate surface quality quickly by combining online detection information of normal and periodic defects with professional quality control skills. To begin, this study creates a set of assessment criteria for HMP surface quality based on length, total defect area, and total area of various types of surface defects on the plate. The analytic hierarchy process (AHP) is then developed to identify based on the operator’s experience and expert knowledge, the weights of the classified defects are then determined using the analytic hierarchy process (AHP). Finally, the evaluation grades for each plate may be calculated. The evaluation findings may benefit not only in improving production efficiency, lessening labor intensity, and reducing waste caused by cutting to length, but also in boosting the intelligent control capability of the HMP manufacturing technique.
Object: Based on the comparisons of the somatosensory event-related potentials (ERPs), the object of this study is to investigate the underlying cognition mechanism of somatotopy and the homology of ...tactile sensation between the projected fingers in the residual limb and the natural fingers in the intact limb. Methods: One amputee subject and three able-bodied subjects were recruited. The forearm amputee had a clear projected finger mapping (PFM) that could evoke the tactile sensation of the entire five missing fingers. Transcutaneous electrical nerve stimulation (TENS) was used to evoke the sensation pattern of touch. Stimulation locations were divided into three groups: the locations of Group PA (projected-finger of amputee-subject) were located on the entire five projected fingers for the amputee subject, the locations of Group NA (natural-finger of amputee-subject) were located on the entire five natural fingers for the amputee subject, and the locations of Group NH (natural-finger of healthy-subject) were located on the bilateral natural index fingers for the able-bodied subjects. The somatosensory ERPs evoked by the stimulations were recorded. We measured the latency and amplitude of the ERP components and made statistical analyses for them. Main results: Since the ERP components of the early-stage are similar for both the stimulation in the projected fingers and the natural fingers, it can infer that the delivery pathway of the projected finger was similar to that of the natural finger. The second finding of the study is that, as the processing of sensory sensation in the cortex of the three groups is similar, it can also infer that the somatosensory evoked by the external stimuli are also similar. Conclusion: The present findings suggest that the somatotopy and the homology of tactile sensation between the projected fingers in the residual limb and the natural fingers in the intact limb have evident uniformity. We infer that the median nerve and the ulnar nerve of the peripheral nerve may divaricate new pathways, and these pathways would have been linked to the PFM.
Previous studies have found that Westerners value high intensity positive emotions more than people in China and Japan, yet few studies have compared actual rates of smiling across cultures. ...Particularly rare are observational studies of real-time smiling (as opposed to smiling in photos). In Study 1, raters coded student ID photos of European American and East Asian students in the U.S. In Study 2, observers coded people's smiles as they walked outside in the U.S. and China. Both studies found that people from East Asia smiled much less-about 50% less. These differences could reflect differences in happiness across cultures, norms of smiling, or differences in ideal affect.
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CEKLJ, FFLJ, NUK, ODKLJ, PEFLJ, UPUK
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•Monodispersed AuNPs self-assembled to form a close packed film.•The close-packed AuNP/ITO electrode is used for detection of dopamine.•The homogenous active sites contribute to ...improved signal reproducibility.
Electrochemical sensors benefit from low cost and fast detection speeds, which makes them suitable for routine analysis of small biological molecules such as dopamine (DA). DA is a neurotransmitter that plays an important physiological role and can be used as a marker for conditions such as depressive disorder and Parkinson’s disease. In this communication, electrodes modified with self-assembled gold nanoparticles (SA-AuNPs) were used as electrochemical sensors for the detection of DA with the aim of achieving better signal stability among the same batch of electrodes. High signal reproducibility among the SA-AuNP-modified electrodes was obtained due to the more orderly packing of AuNPs leading to relatively consistent electrochemical resistance and homogeneous mass transport.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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