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Abstract Recently, the applications of cold atmospheric plasma (CAP) in liquid treatment have attracted increasing attention owing to its excellent medical efficacy. It has been proved that CAP can effectively enhance the biological activity of vegetable oils due to the generation of reactive species. Optimising the reactor parameter is an important approach to regulate reactive species in plasma‐activated oil to obtain better biological effects. In this study, a self‐made jet array driven by a pulsed power supply was used to generate large‐area plasma to irradiate perilla seed oil (PSO), with the formation of plasma‐activated perilla seed oil (PAPSO). By means of laser‐induced fluorescence and chemical titration, the relative density of hydroxyl radical radical in plasma jet, as well as the activity of PAPSO were measured under different discharge parameters, and realised the control of the activity of PAPSO. In vitro experiments showed that PAPSO significantly enhanced its ability to inhibit cancer cells proliferation and induce apoptosis after plasma treatment, which provides a reference for cancer treatment. This study is helpful to further understand the influence of plasma dose effect on the activity of media and provide guidance for related plasma medical applications.

Abstract In 2019, triggered lightning was used to directly strike phase C of a 1.5 km, 10 kV double‐circuit distribution line in Guangzhou, China, with 2 flashes (13 return strokes) recorded. This paper presents the characteristics of induced voltage at the closest pole on the parallel line. The induced voltage is bipolar, which can be divided into 3 stages: negative increase stage, fast and positive transition stage and slowly returning to zero stage. The positive peak value of phase A voltage ranges from 111.4 to 228.9 kV and that of phase C voltage is from 90.1 to 200.9 kV, corresponding to lightning current from −8.9 to −29.9 kA. The positive peak value of the induced voltage is approximately 3 to 10 times the negative peak value. The negative peak, positive peak and positive 10%–10% duration time of induced voltage show a good linear relationship with the peak value of the return stroke current. There was no flashover occurred during the whole process. The result in this paper can provide data support for numerical simulation and line protection analysis.

In view of the limitations of directional drilling technology and equipment for underground gas drainage in coal mining areas, such as low degree of automation, low drilling ratio of target formation, slow drilling rate of rock formation, and small diameter, the research of rotary geosteering drilling technology and equipment underground coal mine has been carried out, with the core technical problems has overcame such as wireless remote control operation of directional drilling rigs, mechanically automatic drill pipe addition, real-time parameter monitoring and fault diagnosis, coal and rock identification while drilling, and trajectory rotation control, ZDY25000LDK electro-hydraulic controlled directional drilling rig, BLY800/12 mud pump truck with high-pressure and large-volume, YSG(A) Mine geosteering MWD system by dynamic azimuth gamma, ϕ133 mm hydraulic push type rotary steering drilling system and supporting drilling tools have developed, with the maximum torque was 25 000 N·m, the automatically add drill pipe time was less than 55s of the directional drilling rig, the rated flow was 800 L/min of the mud pump truck, the natural gamma measurement error was less than ±5% and the stratum exploration distance was ≥0.5 m of the geosteering MWD system, the applicable speed range was 80−200 r/min and the deflection force was 1.4 t of the rotary steerable drilling system; geosteering drilling technology and rotary steerable drilling technology for near horizontal hole has developed with the technical characteristics and process flow are introduced in detail. The field test was carried out in Tangjiahui Coal Mine in Inner Mongolia. 4 directional drillings were completed, with the maximum drilling depth was 820 m, the total footage was 2 419 m, the directional drilling diameter was 172 mm, the drilling efficiency was increased 25% in coal seam and 30% in rock, which realized the directional drilling from “geometric steering” to “rotary geosteering” underground coal mine, the intelligent level and drilling trajectory quality of underground directional drilling in coal mine has been improved, and provided technical equipment support for efficient underground gas drainage and intelligent mine construction.

Abstract In 2018–2019, two types of rocket‐triggered lightning tests, that is, striking to ground and distribution line, were conducted in Guangdong, China. The main focus of this paper is to compare the waveform parameters of the return strokes (RS) from the two tests. For current, the 10%–90% risetime of RS from lightning striking to distribution line is 2.4 times higher than that striking to ground, and the differences in the other parameters are small. For close magnetic field, the RS from lightning striking to distribution line have a lower peak (30% lower after considering the peak current) and a larger risetime and half‐peak width time; besides, it is necessary to divide the front edge of the close magnetic field waveform into two parts: leader (BL) and return stroke (BRS). For close electric field, the close RS electric field peak (ERS) was less sensitive to distance than the leader electric field peak (EL). For far electric field, the differences in waveform parameters of RS from the two tests were not significant, but after considering the peak current, the normalised initial electric field peak (EP) of RS from lightning striking to distribution line was 14% lower than that striking to ground.

Abstract A stepped leader propagated along the previous return-stroke channel in triggered lightning. After the stepped leader decayed, the first bidirectional leader went through the process of initiation, propagation and dissipation. Then the second bidirectional leader initiated at the termination of the decayed first bidirectional leader and propagated toward the ground, generating the fourth return-stroke. The observations were synchronously performed through a high-speed camera and electromagnetic field measurements. The first bidirectional leader was characterized by similar average upward and downward velocities of 0.76 × 106 m/s and 0.67 × 106 m/s. The velocity of the upward positive leader of the first bidirectional leader was noticeably fluctuated, ranging 0.39 × 106–1.78 × 106 m/s. The second bidirectional leader was characterized by a sustainable propagating upward end with an average velocity of 1.82 × 106 m/s. The velocity fluctuation trend of the upward end depends on the neutralization amount of the residual negative charge and the positive charge in UPL.

Abstract This paper reports the observation results of three‐phase overvoltage at the lightning strike point of a 1.5 km, 10 kV power distribution line that was struck directly by rocket triggered lightning to its phase wire C. The arrester of the direct struck phase at the lightning strike point operated in all return strokes corresponding to return stroke current from −3.3 kA to −32.9 kA. The waveform of direct struck phase includes an initial spike before negative peak, operation area of metal oxide varistor, and the final attenuation with oscillation. The overvoltage waveforms of the indirect struck phase at the lightning strike point show a small initial negative peak, rapid transition to a large positive peak, and the final negative attenuation with oscillation. The negative peak value of the indirect struck phase at lightning strike point ranged from −4.1 kV to −25.2 kV and that of the direct struck phase was between −78.1 kV and −167.8 kV. The positive peak value of indirect struck phase was between 0.2 kV and 49.8 kV. The negative peak value, zero‐crossing time and the peak‐to‐peak value of voltage all have a good linear relation with the peak value of lightning return stroke current.

Abstract The authors present a statistical analysis of characteristics of magnetic fields at different distances from triggered lightning experiments on Transmission Line at Guangdong Comprehensive Observation Experiment on Lightning Discharge during the summer of 2019. The histograms and parameters of statistical distributions for the following 22 waveform characteristics are presented, including current peak, 10%–90% risetime, half‐peak width and steepness, leader magnetic field peak, return‐stroke magnetic field peak, magnetic field peak, 10%–90% risetime, half‐peak width and steepness at 15 m, 130 m and 1.55 km. The arithmetic mean of 48 return stroke current peaks is 18.3 kA and the geometric mean is 17.0 kA. The arithmetic and geometric means of the current 10%–90% risetime are 0.6 and 0.6 μs, respectively. The leader magnetic field, return‐stroke magnetic field and magnetic field peak at 18 m, 130 m and 1.55 km are shown linear relationship with current peak values. With increasing the distance(r), the magnetic field peak value decrease, combining the magnetic field characteristics reported by previous studies, the analysis of all magnetic field peaks in different distances suggest linear relationship with r −0.90. The magnetic field 10%–90% risetime shows linear relationship with ln(r) and half‐peak width did not show significant correlation with distance.

Ammonia (NH3) volatilization from paddy fields is a major issue which leads to poor fertilizer use efficiency and is considered a severe threat to the atmosphere. The previous research studies gave importance to the use of nitrogen fertilizers to mitigate NH3 volatilization, while very little emphasis was given to the role of other fertilizers, such as phosphorus (P), for the alleviation of NH3 volatilization in rice fields. Considering P importance herein, we conducted two consecutive field experiments using an innovative, controlled-release, phosphorus-blended fertilizer (CRPBF, with levels CRP0, CRP1, and CRP2). We compared CP0 (in which no fertilizer was applied), CP1 (112.5 kg P ha−1 P of locally recommended fertilizers), and CP2: (P and K blended fertilizers) to determine the best possible way to reduce NH3 volatilization without affecting the yield and quality of rice. The results of the study suggested that the yield of rice increased significantly with the application of CRP1 (11.11 t ha−1) and CRP2 (11.99 t ha−1). The addition of CRP1 and CRP2 to the rice field also enhanced yield-related components, i.e., panicle weight, total spikelets per unit area, spikelets per panicle, and above-ground biomass. CRP0 showed a lower yield and related components when compared to CP2. The addition of CRP1 and CRP2 demonstrated lower protein contents when compared to other treatments. The CRPBF application improved starch content and taste scores, and reduced the chalkiness of the rice grain during both years. The results showed a decreasing trend in NH3 volatilization from CRPBF amendments by improving the nitrogen use efficiency traits when compared to other treatments: CRP2, CRP1, and CRP0 reduced NH3 volatilization by 45%, 35%, and 15%, respectively. The results of this study indicate that, due to the episodic nature of NH3 volatilization, CRPBFs with 50% P and 100% P can markedly reduce NH3 volatilization from paddy fields without compromising the yield and quality of the crop, and could be a promising alternative to the ordinary commercial fertilizers used in rice fields.

Mapping the thunderstorm electrical structure could provide an effective way for lightning-sensitive facilities protection, such as aircraft and maritime assets. However, the weather radar that is normally used to forecast storms and rainfall mainly detects precipitation in the atmosphere and indicates the existence of liquid raindrops and ice particles by reflectivity. Here, we use intra-cloud events of eight thunderstorm days in the warm season, which are detected by VLF/LF Total Lightning monitoring system, to reveal the thunderstorm electrical structures in the 300 × 300 km area of the Pearl River Delta (PRD) region. The differences in height range in four types of time intervals and three types of intro-cloud events proportions are compared on 16 May. With the proportion between 20% and 80% in the time interval of 15 min, the height distribution and the electrical structure of eight thunderstorm days are clearly exhibited. The positive IC events lie in the average height between 7.5 and 12.4 km, while the negative IC events are located between 5.3 and 11.7 km. The electrical structures show the variations during the evolution process, with a dipole structure in most circumstances, while temporary reversions are identified in the initial and the dissipating stage of thunderstorms, presenting the inverted dipole and the tripole structures.

Acute myeloid leukemia (AML) is a fatal disease characterized by the accumulation of immature myeloid blasts in the bone marrow (BM). Cytokine provide signals for leukemia cells to improve their survival in the BM microenvironment. Previously, we identified interleukin-33 (IL-33) as a promoter of cell survival in a human AML cell line and primary mouse leukemia cells. In this study, we report that the cell surface expression of IL-33–specific receptor, Interleukin 1 Receptor Like 1 (IL1RL1), is elevated in BM cells from AML patients at diagnosis, and the serum level of IL-33 in AML patients is higher than that of healthy donor controls. Moreover, IL-33 levels are found to be positively associated with IL-6 levels in pediatric patients with AML. In vitro, IL-33 treatment increased IL-6 mRNA expression and protein level in BM and peripheral blood (PB) cells from AML patients. Evidence was also provided that IL-33 inhibits cell apoptosis by activating p38 mitogen-activated protein kinase (MAPK) pathway using human AML cell line and AML patient samples. Finally, we confirmed that IL-33 activated IL-6 expression in a manner that required p38 MAPK pathway using clinical AML samples. Taken together, we identified a potential mechanism of IL-33–mediated survival involving p38 MAPK in pediatric AML patients that would facilitate future drug development.

The authors present an analysis of different charge transfer modes during upward negative flashes. The analysis includes a total number of 94 pulses that occurred during two upward negative flashes recorded at the Säntis Tower. The pulses included 59 mixed-mode (MM) initial continuous current (ICC) pulses, 17 M-component-type ICC (M-ICC) pulses, 8 return-stroke pulses, and 10 classical M-component (MC) pulses. It is found that the initial stage of the flash is responsible for the largest share of the total charge transferred to the ground. Simulation results for the electric fields associated with the considered charge transfer modes are presented and discussed. Return stroke (RS) and MM pulses were simulated adopting the MTLE model, while MCs and M-ICC pulses were simulated using the guided wave model of Rakov et al. The simulated results are shown to be in good agreement with simultaneous records of electric fields measured at a distance of 15 km from the Säntis Tower. The inferred velocities for MCs and M-ICC pulses range from 2.0 × 10^7 to 9.0 × 10^7 m/s, and the corresponding junction point heights range from 1.0 to 2.0 km. The inferred pulse velocities for RSs and MM pulses range from 1.3 × 10^8 to 1.65 × 10^8 m/s. The inferred current attenuation constants of the MTLE model obtained in this study range from 0.3 to 0.8 km, lower than the value of 2 km previously suggested for RSs in downward flashes. The obtained results support the assumption that the mode of charge transfer to the ground giving rise to MM pulses is similar to that of RSs. The results are also in support of the generally assumed similarity between M-ICC pulses and classical MCs.

Acoustic observation of laboratory simulated lightning discharge can greatly avoid the observation difficulties under natural thunderstorm environment. An acoustic observation experiment based on the impulsive current generation system and a microphone array was carried out and illustrated in this study. A quantitative study on characteristics of response sound pressure initiated from simulated lightning current was performed. The first arrived acoustic N-waves measured at different distances initiated from different discharge amplitudes were compared and analysed. The acoustic amplitude, rise time and duration time defined for N-waves and peak frequencies were found to have an obvious correlation with the discharging amplitudes of simulated lightning currents and the observing distances. The linear change of acoustic amplitude is more obvious than that of the other parameters with the changed discharging amplitude or observing distance. A certain degree of shape change of the simulated lightning current except for the amplitude may not significantly affect the response acoustic characteristics when comparing the first acoustic N-waves from 8/20 μs lightning current and another kind of impulsive current which has a wider shape and two subsequent peaks. The subsequent current peaks in short time delays were proved to successively generate acoustic N-waves independently without overlapping, which meanwhile, indicated a consistent linear relationship of amplitude and time delay between electrical and acoustic pulses.

Aiming at the problems of poor detection accuracy and low efficiency on the roof and floor interface in horizontal well drilling in coal mine, the design idea of explosion-proof azimuth-while-drilling electromagnetic wave logging instrument in coal mine was put forward. In order to suit the working environment of underground coal seam, the change law of the influence of instrument parameters such as source distance and coil installation angle on the signal response was obtained through forward simulation. Through the simulation research on the response of azimuth-while-drilling electromagnetic wave logging instrument, it provided a basis for selection of parameter optimization design of the instruments applicable to the underground coal mine, and the change law of the response of coal rock roof and floor interface was mastered. The application of this instrument will improve the detection accuracy and efficiency on the roof and floor.

In the summer of 2013, a three-dimensional (3D)-based Foshan Total Lightning Location System (FTLLS), embedded with differential time of arrival (DTOA) techniques, was installed and started its operation in Foshan, Guangdong Province, China. In this paper, the geographical distribution and set-up information of FTLLS, the estimated locating errors and locating results, as well as its initial operation results are presented. FTLLS consists of nine sub-stations that receive electromagnetic waves associated with lightning discharges and locates VLF/LF (200 Hz–500 kHz) radiation sources in 3D. The remote sub-stations acquired triggered waveforms with a duration of 0.5 ms, a resolution of 12-bits, and a GPS-based sferic time tags of 24 h per day. Cloud-to-ground (CG) lightning events, intra-cloud (IC) lightning events and narrow bipolar events (NBEs) were located by FTLLS. Based on the Monte Carlo simulation, the two-dimensional horizontal location error is basically less than 100 m, and the vertical error (altitude) is less than 200 m when the lightning event occurs within the network. On the other hand, over 14 million lightning strikes were recorded successfully by FTLLS during the period of May to October in 2014, among which IC events, CG events and NBEs accounted for 65%, 34% and 1%, respectively. It is shown that FTLLS is capable of a fine three-dimensional (3D) location, in which the altitude parameters obtained are reasonable and well consistent with observed data in the previous studies. The location results of thunderstorms were additionally verified through simultaneously-observed radar data.