Design of Protection Module Against Disturbance Induced by Nanosecond Electromagnetic Pulse on Powerline

Electromagnetic coil gun is a new high speed launcher that uses electric energy. One of the most important parts of electromagnetic coil gun is high pulse power supply. The electromagnetic coil gun always needs several even hundreds of pulse power supplies to gain high muzzle velocity and launch heavier projectile. Therefore the timely trigger of the pulse power supply and the controlling and measuring of the charge and discharge voltage become the critical components of electromagnetic coil guns. This paper presents an optimal design of a measurement and control system for the electromagnetic coilgun's pulse power supply. In order to speed up the optimization, CAN bus is introduced to this system, which makes the system superior of improved measurement and control efficiency. The capability of anti-interference electromagnet is enhanced due to adopting fiber as the communication media. The launch thrust and acceleration can be tailored to the needs of the projectile since the stored energy in each module is adjustable.

To study the effects of electromagnetic pulse (EMP) exposure on the morphological change and excretion functions of mouse microglia (BV-2) cells and possible mechanism. BV-2 cells were divided into two groups: the group exposed to EMP at 200 kV/m for 200 pulses and sham exposure group. At 1, 6, 12 and 24 hour after exposure the cells and culture supernatant were collected. Cellular morphological change was observed under invert microscope, the levels of TNF-α, IL-1β and IL-10 in culture supernatant were determined by enzyme-linked immunosorbent assay (ELISA), nitric oxide (NO) and reactive oxygen species (ROS) were detected by nitrate reductase method and DCFH-DA probe, respectively. The protein and phosphorylation levels of ERK, JNK and p38 were measured by Western Blot method. After the cells pre-treated with the inhibitor of p38 (SB203580) were exposed to EMP, the levels of NO and ROS in culture supernatant were detected. It was found that the large ameboid shape appeared in some microglia cells exposed to EMP for 1, 6 and 12 h. Moreover, the number of microglia cells with ameboid shape increased significantly at 1 h, 6 h and 12 h after EMP exposure compared with sham group (P < 0.05). The levels of cytokines, such as TNF-α, IL-1β and IL-10, in culture supernatant did not change obviously after EMP exposure. The levels of NO and ROS increased significantly at 1h after EMP exposure, reached the peak at 6 h, began to recover at 12 h and recovered to sham group level at 24 h (P < 0.05). Western blot results showed that the protein and protein phosphorylation levels of ERK and JNK did not change significantly after EMP exposure, however, the protein and protein phosphorylation levels of p38 increased obviously at 1 h and 6 h after EMP exposure, compared with sham group (P < 0.05). In addition, the pretreatment of p38 inhibitor (SB203580) significantly decreased NO and ROS production induced by EMP. EMP exposure may activate microglia cells and promote the production of NO and ROS in mouse microglia cells, and p38 pathway is involved in this process.

In order to measure the electric field of electromagnetic pulse(EMP) with nanosecond rise time, a kind of broadband E-field sensor based on asymptotic conical antenna is proposed. The performance of the antenna is verified by modeling and simulation. An optical transmitter is designed to realize the electro-optical conversion and a fiber is used to transmit the signal. The output voltage of the sensor is integrated by Matlab. The performance of the sensor is tested by experiment. Research results show that this kind of measurement system has the characteristic of small size, good linearity, high noise immunity and wide-band response and it can be used to measure the E-field of EMP with nanosecond rise time. The development of the E-field sensor is of great significance for the measurement of EMP and further research on the characteristics and protection of EMP.

To study the effects of electromagnetic pulses (EMP) on pathological changes and apoptosis of spleen lymphocytes in mice. The male BALB/c mice (18 ∼ 22 g) were sham-exposed or exposed to EMP at 200 kV/m for 400 pulses a day for 7 days. On the 1st, 3rd, 7th, 14th 28th days after exposure the mice were killed. The weight of mice, the pathological change and the weight of mouse spleens were observed, the spleen indexes were calculated. The lymphocytes extracted from spleens were counted. The apoptosis and cell cycle of the lymphocyte were detected by flow cytometry, and the migration of the lymphocyte was measured by transwell assay. No pathological changes were found on the first day after exposure. However, the expanded sinusoid and the changed structure of spleen corpuscle on the 3rd day after exposure were observed. There was no difference of spleen indexes between the sham group and the exposure group on the 1st and 14th day after exposure. On the 3rd and 7th days after exposure, the spleen indexes of exposure group were significantly higher than those of sham-exposure group (P < 0.05). On the 28th day after exposure, the spleen indexes of exposure group was significantly lower than those of sham-exposure group (P < 0.05). The number of spleen lymphocytes on the 3rd and 7th days after exposure in exposure group increased significantly, compared with sham-exposure group (P < 0.05). But there were no differences of apoptotic cells and cellular cycle between the exposure group and sham-exposure group (P > 0.05). The ability of migration of the exposure group was significantly higher than that of sham-exposure group (P < 0.05). than the sham group (P < 0.05). The spleen of the male mouse is one of the target organs of EMP. After exposure to EMP, the number of spleen lymphocytes increased. But there were no differences of cell apoptotic cells and cell cycle between the sham group and the exposure group, due to the enhanced migration of lymphocytes induced by EMP.

To evaluate the threat of high-altitude electromagnetic pulse HEMP environment on a shortwave receiving antenna system, pulsed current injection tests for the front-end equipments near the antenna, including some commercial surge protection devices, have been conducted. Both a fast rise-time nanosecond square waveform pulser and a double exponential waveform pulser with high current output, are adopted to check the responses of various surge protection measures. Results show that three protection devices have played essential roles in preventing against HEMP conducted disturbance. Firstly a gas discharge tube at the end of the whip antenna breaks down within a few nanoseconds, since it suffers an overvoltage much higher than its nominal DC breakdown voltage. Then a transient voltage suppressor (TVS) in the commercial signal surge protection device also responses quickly to clamp the line voltage. And the amplifiers in the signal transmission equipments also limit the residual voltage of the disturbance propagating forward, as they are readily to enter the saturation mode under excess inputs. Therefore, the system can withstand either a fast rise-time nanosecond square waveform pulse with an voltage amplitude of 3.5 kV, or a double exponential (20/500 ns) waveform current pulse with an amplitude of 1.8 kA. The only effect is that the latter signal transmission equipment outputs a disturbance signal with a saturated amplitude ( 3 V) which lasts for several microseconds. This implies that , when combining the selected commercial surge protection devices properly, it is practicable to protect similar low working voltage antenna systems against both lightning electromagnetic pulse and HEMP.

Objective To investigate the effects on rat hearts induced by three kinds of band electromagnetic radiation (X-band, S-band and Electromagnetic pulse (EMP))and the differences of injury grade. Methods 180 healthy male Wistar rats were randomly divided into four groups:control group (n = 36) and three experimental groups (n = 48) treated with X-band, S-band high power microwave and EMP, respectively. At different time-points (6 hours,1, 3, 7, 14, 28 days,6 months and 12 months) after irradiation, the rats were killed and the pathological changes of the heart tissues were observed. Results The rat hearts of three experimental groups were differently injured, but the change character was similar. The injury was more and more serious at 6 hours -7 days:deranged cardiomyofilaments, decreased glycogen, Pyknosis;lysed Purkinje cells;swelling matrix and serous exudates. The injured hearts showed convalesecence at 14-28 days, and returned to normal progressively at 6-12 months.compared with the injured hearts irradiated by the three different band wave electromagnetic at the same time: the hearts were injured most seriously irradiated by X-band high power microwave(HPM), and slighter for those by S-band HPM, most slightest for those by EMP. Those in control group were normal. Conclusions Three kinds of band wave electromagnetic radiation injure the rat hearts differently. The injury grades are X > S > EMP. The research indicates that the shorter wave length or higher frequency make rat hearts injure more seriously, and need the longer time to resume. Key words: Electromagnetic radiations; Heart; Histological; Injury

High power electromagnetic pulse interference and even destruction of unmanned aerial vehicles is a very effective way to deal with the threat of small unmanned aerial vehicles (UAVs).The interference and damage of high power electromagnetic pulse to UAV system is mainly through the way of front door coupling and back door coupling. In this study, the damage of UAVs by high power electromagnetic pulse are analyzed, and the target vulnerability of UAVs under the electromagnetic pulse source is analyzed. According to the damage effect, the damage level of the high frequency electromagnetic pulse to UAVs is divided into three levels, namely the interference level, the damage level and the failure level, and the main targets of electromagnetic pulse are analyzed. The results show that the most vulnerable parts of the UAVs are the receiver and the electronic governor. Therefore, in future research and practical application, it is necessary to study the damage and destruction of the electromagnetic pulse to the receiver and the electronic governor. And the optimum frequency of damage should be determined based on the circuit configurations of the receiver and the electronic governor.

M. Dreger, M. Wiesenfarth, T. Schmid and A. W. Bett Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstrase 2, 79110 Freiburg, Germany, max.dreger@ise.fraunhofer.de, phone: +49 761 4588 5007, fax: +49 761 4588 8555 ABSTRACT: In high concentrating photovoltaic (HCPV) modules the solar radiation is focused on high efficient multi-junction solar cells. One option to distinguish between different system approaches is the applied optics. For example, Frensel lenses or parabolic mirrors can be used as primary optics. Another aspect of the module design is how the thermal energy is distributed. There are actively and passively cooled systems. In any case, the way of thermal management is essential for the high performance of the system. In this paper passively cooled systems with mirrors as primary optics are investigated. Different designs of modules with on-axis, off-axis and Cassegrain optics were chosen and evaluated in terms of thermal management, optical efficiency, acceptance angle and manufacturing efforts. For the analysis of the optical and thermal behavior, ray tracing and FEM simulations were applied. In terms of temperature of the solar cell the Cassegrain design has the lowest operating temperature as the heat spreader does not shade the primary optics and can be generously dimensioned. Comparing the acceptance angle and the optical efficiency a special on-axis design with the heat spreader assembled inside of the module performs best. Keywords: CPV module, module design, mirror optics, passive cooling, thermal management, optical efficiency 1. INTRODUCTION With concentrating photovoltaic (CPV) systems, a cost competitive and robust technology is available to the market. In CPV modules the solar radiation is focused on multi-junction solar cells. The key success factor for the technology is the high efficiency of the multi-junction solar cell. Several system designs have been realized. One approach to classify the different system designs is the primary optics used. For example, parabolic mirrors are applied. This optics is particularly suitable for very high concentrations of 1000x and more. As the solar cell is still costly, increasing the concentration factor is one way to reduce the module costs. In addition, in comparison to lens optics, mirror optics show no chromatic aberration. Another aspect of the module design is how the thermal energy is distributed. There are actively and passively cooled systems. In any case, the way of thermal management is essential for the high performance of the system. Large primary optics can be used if active cooling is used. A well-known example for such a system is the dish system developed by Solar System in Australia [1]. If the passively cooled (so called micro dish) option is chosen, the size of the primary mirror is limited. The advantage is that passively cooled systems need very low maintenance and do not require any failover. An early grid connected passively cooled system installed in 2005 is the MicroDish developed by Spectrolab [2]. However, there are multiple ways to assemble the optics. Hence, there are different system designs as for example developed and demonstrated by SolFocus [3], Beghelli [4, 5], AtemEnergia [6, 7], Soltech Renovables [8] or Brightleafs technology [9]. In this work different concepts for micro dish systems are investigated using theoretical modeling. The advantages and challenges of the approaches are compared. 2 INVESTIGATED CPV MODULE DESIGNS CPV is a particularly integrative technology. Therefore, it is very important to match the design of all components very well. In addition, the manufacturing processes must be planned already in the design phase. These aspects need to be considered when starting a module development. In this paper, different designs with mirror optics and passively cooled receivers are evaluated. All investigated systems were designed for a geometrical concentration of 1000x. The solar cells, electrical contacts and mirror optics are protected against ambient conditions like dust and humidity. This is realized by incasing the components with a frame and cover glass. Thus, high reliability and long-term stability of the module can be guaranteed. The design approaches are different particularly in the arrangement of the optics. On-axis, off-axis and Cassegrain optics were investigated. For each module design, the design of the heat spreader was adapted. In the following the different designs are described. In Design 1, shown in Figure 1, an off-axis optics is used. The light path is indicated in black. The mirror is comprised of a paraboloidal section. The optical axis does not contain the mechanical center of the input aperture. The solar radiation is reflected to the solar cell assembled parallel to the incoming radiation vertically onto the module wall. Hence there is no shading of the mirror by the solar cell.

In this paper, the propagation laws of High-altitude electromagnetic pulse (HEMP) propagating into seawater is researched, so, the pulse wave characteristics is gotten which was changed with the changing of depth into sea in time domain. The work in this paper will have important meaning to research electromagnetic pulse effect and electromagnetic pulse protection.

Objective To investigate the effects of electromagnetic pulse (EMP) on reproductive function of male adult mice. Methods A total of 48 healthy adult male BALB/c mice (8 weeks old) were randomly divided into sham group and EMP group with 24 animals in each group. The mice were whole-body exposed or sham exposed to EMP at 720 kV/m for 100 pulses with 1 Hz repetition rate and 40 ns pulse width. At 1, 7, 14 and 35 d after EMP exposure, the mice were anesthetized and the sperms were collected from the bilateral epididymal tail. After that, the sperm quality including the number of sperms, the ratio of abnormalities and the survival rate was evaluated. In addition, the morphology of testis was observed by HE staining and the diameter of seminiferous tubules was measured by Image J 1.43 u software. The protein level of stem cell factor (SCF) and glial-derived neurotrophic factor (GDNF) in testis tissue were detected by ELISA and Western blot. Results The sperm quality and the morphology of testis did not change obviously at different times after exposing mice to EMP at 720 kV/m for 100 pulses, compared with sham group (P>0.05). The diameters of seminiferous tubules at 1, 7, 14 and 35 d after exposure were (196.85±16.65), (196.79±14.33), (196.35±22.71) and (198.60±25.88) μm in exposed mice, respectively, while (204.31±27.13), (197.07±18.11), (194.37±21.45) and (200.59±19.36) μm in sham exposed mice, respectively. There was no significant difference between two groups (P>0.05). Additionally, the levels of SCF and GDNF in testis tissue between EMP group and sham group had no statistically significant difference (P>0.05). Conclusion Under this exposure condition, EMP couldn′t affect the reproductive function of male adult mice. Key words: Electromagnetic pulse; Mice; Testis; Sperm quality; Seminiferous tubules

Objective To investigate the effect of electromagnetic pulse (EMP) on the the link-structure of heart intercalated discs(ID), and to explore the mechanism involved. Methods EMP was provided by the EMP simulator of our department, the parameters was as following: 200 pulse, different field intensity(50～400 kV/m). The research objects were female SD rats, they were randomly divided into five groups, each group has six rats. At 12 h after EMP exposure, the lanthanum nitrate tracer method and the transmission electron microscope (TEM) were used to observe the structural changes of left ventricular myocardium. Microarray was used to evaluate the gene differential expression of left ventricular myocardium. Results At 12 h after EMP exposure, the width of ID gap was widen gradually with field augmentation, lanthanum nitrate in ID gap was incrsased gradually with field augmentation. Compared with the control group, there were 108 genes standard altered in gene expression profile in rat myecardium after EMP in the 200 kV/m group. 51 genes (synaptorin, VGF, HSP70, etc.) were up-regulated while 57 genes (NAD, FGF, Tff3, etc.) were down-regulated. Conclusions Space between intercalated discs was wided along with field augmentation after EMP exposureed. The changes in ID of cardiac muscle was remarkable at 400 kV/m. There were 108 genes altered in gene expression profile in rat myocardium after EMP. Key words: Electromagnetic pulse (EMP); Intercalated discs (ID); Lanthanum nitrate; Microarray; Rat

To investigate the exposure effect of electromagnetic pulse (EMP) on the structure and secretion of pituitary gland in rats. Forty-eight male SD rats were randomly divided into eight groups. Four groups were subject to the EMP exposure of 200 kV/m and the others received a sham exposure. At different time points (12, 24, 48 & 96 h) post-exposure, the pathological changes of pituitary gland were observed by light and transmission electron microscope. And the serum levels of prolactin (PRL), growth hormone (GH), adrenocorticotropic hormone (ACTH), thyroid stimulating hormone (TSH) and luteinizing hormone (LH) were measured dynamically by radioimmunoassay. At 12 h post-exposure, swollen mitochondria with cristae loss, dilatation of Golgi complex and diffusive lysosomes were found in endocrine cells of pituitary gland. The above changes became gradually worse. Mitochondrial vacuolization, the formation of myelin figures, distinct dilatation of endoplasmic reticulum, the occurrence of numerous secondary lysosomes and the clustering of heterochromatin under the nuclear membranes could be observed at 48 h. These lesions were alleviated to some degree at 96 h. The serum levels of PRL and ACTH both increased significantly at 12 h (P < 0.01, P < 0.05) and returned to normal at 24 h. The level of GH decreased significantly at 12 h and then returned gradually to normal at 48 h. The level of TSH decreased at 12 h and reached the lowest point at 24 h, then returned to normal at 96 h. LH increased significantly from 24 h to 96 h. The EMP exposure of 200 kV/m may induce the changes of the structure and secretion of pituitary gland in rats.

There are some suitable methods for the measurement of ultra-short solitary electromagnetic pulses (EMP) that are generated by high power microwave generators. The characteristics of EMPs are high power level (Pmax = 250MW) and very short time duration (tp2 ns). Special requirements for measurement methods have to be considered because of the speciflc EMPs properties. In the paper, two suitable methods for this application are presented. The flrst one, the calorimetric method, utilizes the thermal impacts of microwave absorption. The second method presented | the magneto-optic method | uses the Faraday's magneto-optic efiect as a sensor principle. A combined calorimetric sensor was realized and there were made some experimental EMP measurements with good results. The sensor utilizing the magneto-optic method is still in development. DOI: 10.2529/PIERS060901081439 In connection with the events of the last few years and with the increased number of terrorist activities, the problem of identifying and measuring the impact of electromagnetic weapons or other systems occurred. Among these weapons or systems there are also microwave sources which can reach extensive peak power of up to Pmax = 250MW. Solitary, in some cases several times repeated, pulses lasting from tp 2 ns cause the destruction of semiconductor junctions. The analysis of possible measuring methods convenient for the identiflcation and measurement of the ultra-short solitary electromagnetic (EM) pulses is presented in this paper; some of the methods were selected and used for practical measurement. 2. METHODS 2.1. Method Based on Faraday's Induction Law One group of methods is based on the application of Faraday's induction law where the pulse is located by sensor (coil with Ns = 1¥50 turns). The signal induced in the coil is led to the recording device, generally an oscilloscope. Due to safety requirements, the distance between the sensor and the oscilloscope is l = 50m. This parameter introduces quality decrease of the recorded information in the way of the signal amplitude reduction, change of the signal phase and the pulse prolongation. The elimination of this limitation is in Version I, depicted in Figure 1, made by backward correction exploiting the Laplace transform. Pulses up to limit pulse length Tmax = 1ns were measured by this method and magnetic ∞uxwas evaluated (4). Version II exploits the possibility of principal elimination of in∞uence of the transmitting line between the sensor and the measuring device by an analogue U/f. converter. Available measuring devices can achieve measured pulses with the limit length Tmax = 5ns. The solution in Version III is similar to Version II; the difierence is in the digital converter applied. By an available measuring devices application and fulfllled sampling theorem we can measure pulses with the limit length Tmax = 20ns. 2.2. Method Based on Faraday's Magneto-optic Efiect Version IV in Figure 1 is based on Faraday's magnetooptic efiect (4). The connection between the sensor and the measuring device is implemented in the optical wavelength. There are three basic types of the possible active sensors. The flrst type is a garnet with high Verdet constant, the second one is an optic flber and the third one is based on magneto-optic properties of ferromagnetic mono/multi thin fllm. Other types of Version IV sensors are based on the magneto-optic Kerr's efiects (MOKE), or surface MOKE (SMOKE) efiect. By an available measuring devices application we can measure pulses with the limit length Tmax = 0:1ns. The named methods indicate the electromagnetic parts of the wave | electric or magnetic. They don't express the power conditions of the electromagnetic wave. For some of the measurement it is essential to evaluate power ∞ow through the deflned area.

The paper focuses on establishing the effect of nanosecond electromagnetic pulses (NEPs) with different amplitudes on the formation of the structure of cast aluminum matrix composites of the Al–Mg2Si pseudobinary system with hypoeutectic (5 wt. % Mg2Si) and hypereutectic (15 wt. % Mg2Si) compositions. As the NEP generator amplitude in composites containing 5 and 15 wt. % Mg2Si increases, the matrix alloy structural components (α-solid solution and eutectic) are refined, while no significant differences in the sizes and morphology of Mg2Si primary crystals were observed in the hypereutectic range of compositions. Presumably, the observed nature of the NEP effect on the structure of composites in the hypereutectic region of compositions is associated with the features of their crystallization behavior. The temperature range of the L + Mg2Si two-phase region presence is much lower than NEP irradiation temperatures. Apparently, this is the reason why NEPs have no effect on the thermodynamic state of Mg2Si primary crystal/melt interfaces. It was shown that a promising option for the simultaneous modifying effect on all structural components of Al–Mg2Si aluminum matrix composites (solid solution, eutectic, Mg2Si primary particles) is a combination of thermal-rate treatment and irradiation of melts by NEPs, as well as additional melt processing by NEPs during crystallization.

Objective To explore the changes of SOX9 and WT1 expressions in rat Sertoli cells irradiated by EMP ( electromagnetic pulse),S-HPM ( S-band high power microwave) and X-HPM ( Xband high power microwave).Methods Primary Sertoli cells were isolated from 3-week-old Wistar rats and its purity was immunocytochemistrically indentified with WT1.After exposure to 6 × 104 V/m EMP,100 mW/cm2 S-HPM and X-HPM for 4 min respectively,SOX9 and WT1 expressions in Sertoli cells were determined with real-time PCR and Western blot,respectively.Results SOX9 mRNA expression was decreased at 6 and 12 h post-irradiation of three different bands of electromagnetic microwave ( F =15.20and 4.84,P ＜ 0.05 ).SOX9 protein expression was also decreased at 6 and 24 h after irradiation ( F =8.46 and 7.47,P＜0.05).WT1 mRNA expression was decreased at6 and 12 h (F=13.46 and 5.08,P ＜ 0.05 ),but its protein expression was decreased only at 24 h post-irradiation ( F =10.26,P ＜ 0.05 ).Conclusions Three bands of electromagnetic radiation reduce the expressions of SOX9 and WT1 in rat Sertoli cells,which may provide molecular foundation for genital system hazards induced by microwave radiation. Key words: Electromagnetic radiation ; Sertoli cells ; SOX9 ; WT1