Low Inductance Research Articles

An Active Damping Control Method for Reduced DC-Link Capacitance PMSM Drives With Low Line Inductance

The power density can be improved and the system cost can be saved in the reduced dc-link capacitance motor drive system. The line inductance can also be diminished to reduce the system volume further. In previous research works, the active damping control methods mainly concentrated on the drive system equipped with a larger line inductor. In this article, a dc-link voltage estimation feedback-based active damping method is proposed to suppress the grid current harmonics and improve the drive system stability with low line inductance. The dc-link voltage ripple caused by the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> resonance is analyzed to evaluate the direct dc-link voltage feedback-based active damping control method. To improve the damping performance, the resonant component of the dc-link voltage caused by the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> resonance could be obtained through the grid current to establish the feedback control loop. The sampling delay should be compensated to improve the control performance. The stability of the drive system is evaluated by the Nyquist plots of the impedance model, and the grid current is also analyzed, which could satisfy the harmonic requirements of IEC-61000-3-2. Experimental results are performed to verify the effectiveness of the proposed method.

Synchronous Trigger Technology and Discharge Characteristics of Multiparallel Gas Switches Based on Parallel Plate Transmission Lines

This article proposes a gas switch with a low inductance (31 nH), a wide operating coefficient (≥50%), a rapid breakdown (< 100 ns), and a high intensity of current (532 kA/7.8 C). We also design a synchronous trigger system for discharging multiparallel switches while ensuring significant scalability and low cost. The maximum amplitude of the outputs of 16 pulses under high-resistance loads was 77.1 kV/14 ns (10%–90% rise time). Following this, we built a 200-kJ compact pulsed power device by using parallel plate transmission lines. This device can reduce the overall inductance by 14% compared with the previous generation of devices. We also investigated the factors influencing synchronous discharge as well as the conditions for the synchronous discharge of 16 gas switches in parallel. At an operating voltage of 70 kV, the maximum amplitude of the short-discharge current was 5.5 MA (deviation was less than 3%) and the shortest rise time was around <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1 ~\mu \text{s}$ </tex-math></inline-formula> (10%–90% rise time). The stable operation of the device is important for physics research on the load.

Speed/Torque Ripple Reduction of High-Speed Permanent Magnet Starters/Generators With Low Inductance for More Electric Aircraft Applications

With the electrification trend of future aircraft, high-speed permanent magnet starters/generators (PMSs/Gs) will potentially be widely used in onboard generation systems due to their high power density and high efficiency. However, the per-unit reactance of such high-speed machines is normally designed to be very low due to limited onboard power supply voltage and large electrical power demand, which can result in large current ripples in the machine and thus large torque ripples especially when the machine is fed with a semiconductor-based inverter of a lower switching frequency. The torque ripples may further lead to speed oscillation and generate severe vibrations and noises that are harmful to the mechanical system and human beings around. In this article, a speed/torque ripple reduction method for high-speed PMS/Gs with a low inductance is proposed to improve their performance within a wide speed range. An active damping technique is applied to the speed loop to increase the anti-disturbance capability and generate a smoother reference for the current loop, whereas an adaptive output voltage saturation limit is utilized for the current loop to limit the peak value of current to prevent overcurrent and torque spikes. The parameter tuning criteria are derived through a thorough analysis. Finally, the proposed method is validated on a high-speed PMS/G with an inductance of 99 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{H}$ </tex-math></inline-formula> . The results show that the speed ripples and torque ripples are reduced by over 50% within a speed range of 2–14 krpm.

Packaging of a 10-kV Double-Side Cooled Silicon Carbide Diode Module With Thin Substrates Coated by a Nonlinear Resistive Polymer-Nanoparticle Composite

Medium-voltage silicon carbide (SiC) power modules are a critical component in grid-bound power conversion systems, and the packaging of these modules dictates the performance and reliability of the systems. One of the key issues for packaging the modules is managing the tradeoff between heat dissipation and insulation. To improve thermal performance without sacrificing insulation, a 10-kV SiC full-wave diode rectifier was designed and fabricated by incorporating double-sided cooling and wirebond-less interconnection and by utilizing thin alumina direct-bond copper substrates. To ensure that the substrates met insulation requirement, triple points on the substrates were coated by a nonlinear resistive polymer-nanoparticle composite to reduce electric field concentration. The nonlinear resistive coating increased the partial discharge inception voltage of the substrate with 0.5-mm thick alumina to 17.3 kV, an 84% improvement over that of the substrate without the coating. Electrical and thermal simulations of the module showed a low power loop inductance of 3.51 nH and a low junction-to-case thermal resistance of 0.114°C/W. The feasibility of the packaging techniques was demonstrated from successful fabrication and functional testing of the packagedmodule.

Analysis and Optimized Design of a Novel Compact Orthogonal Controllable Reactor

Orthogonal controllable reactors (OCRs) have the advantages of low distortion and linear inductance regulation. However, traditional OCRs suffer from two vital problems, namely, their small inductance regulation range and large space occupation. To solve these issues, a new compact OCR is proposed in this study. First, the magnetic circuit of the reactor is established through theoretical analysis. Second, the simulation model is established and the inductance regulation characteristics of the reactor are obtained. Third, the key parameters are optimized for better performance based on Pareto optimality and a genetic algorithm. Finally, based on the optimized parameters, a new prototype of the OCR is developed and experimental work is carried out to verify the analysis. The results show that, compared with the traditional model, with the same material consumption, the space occupation of the new topology is reduced by 53.7% and the inductance regulation range is increased by 69%. Experimental results also show that increasing the area of the orthogonal region can significantly increase the inductance regulation range of the reactor. Based on the OCR, the filter with a variable resonance frequency can be formed, which is of significant application value in situations where the harmonic frequency is constantly changing.

Design and Multiobjective Optimization of a Double-Stator Axial Flux SRM With Full-Pitch Winding Configuration

In this article, a novel axial flux double-stator switched reluctance motor (AFDSSRM) is presented and optimized for electric vehicle applications. AFDSSRM adopts the axial arrangement of double-stator and inner rotor structure with a full-pitch winding configuration. The flux generated by the two stators cancels each other at the unaligned position, and then, a low unaligned inductance barely affected by saturation is achieved, which is the primary advantage of the AFDSSRM. First, the topology and power equation of the motor are presented briefly. Due to a large number of dimensional parameters of the proposed structure, comprehensive sensitivity analysis is used to classify the design parameters into strong- and weak-sensitive classes, and a multilayer optimization approach is adopted for the variables of both classes. The response surface method combined with the multiobjective genetic algorithm is employed to optimize the strong-sensitive variables, while the Taguchi algorithm is applied to optimize the weak-sensitive variables. Moreover, the 3-D finite element model is established to analyze the electromagnetic characteristics of the motor. Finally, a prototype motor is manufactured, and the experimental results verify the effectiveness of the proposed structure and the optimization method.

Flat-end mill machining analysis of processed CrMnFeCoNi high-entropy alloys

ABSTRACT High-entropy alloys are emerging materials and are widely studied at the synthesis and characterization levels. Their machinability study and product realization are still at a nascent stage. Conventional machining operations are necessary to ensure part assembly and surface quality. Hence, end-mill machining is carried out to check the machinability of the most ductile equiatomic and non-equiatomic CrMnFeCoNi high-entropy alloy (HEA) with a green manufacturing concept. Theoretical and experimental analyses examined the effect of percent composition of an element in a high-entropy alloy and machining parameters (spindle speed, depth of cut and feed per tooth) on the cutting forces, chip morphology, machined surface topography, surface micro-hardness and tool wear mechanism. Kistler dynamometer installed in CNC vertical milling machine is used with AlTiN-coated tungsten carbide tool to record the cutting forces and moments. The microstructure anisotropy induced by low vacuum induction melting of varying compositions of elements in high-entropy alloys influenced the machining results. Feed force values were higher for the non-equiatomic HEA sample than for the equiatomic CrMnFeCoNi HEA. SEM and EDS mapping has revealed microhole and microcrack surfaces after machining. Equiatomic CrMnFeCoNi HEA has shown the highest microhardness of 984 Hv than the non-equiatomic HEA sample.

Low dose thymoglobulin versus basiliximab in cytomegalovirus positive kidney transplant recipients: Effectiveness of preemptive cytomegalovirus modified strategy

BackgroundWe performed a retrospective trial to determine asymptomatic CMV reactivation and CMV disease in kidney allograft recipients with positive CMV serostatus. MethodsPreemptive modified strategy under low dose thymoglobulin versus basiliximab induction was evaluated. Patients were monitored by CMV-polymerase chain reaction (PCR); if the viral load was >4000copies/μl, they received valganciclovir adjusted for their renal function. Results132 recipients were included in the study, 84 and 48 receiving basiliximab and thymoglobulin induction respectively, and followed up for 12 months. Asymptomatic CMV reactivation was significantly higher for thymoglobulin (77.1% vs. 16.7%, p<0.001). Treatment groups had similar rates of CMV disease (3.6% vs. 2.1%, p 0.538). The significant difference in asymptomatic CMV reactivation between two treatment groups did not have any impact on 1 year graft function (71±26ml/min vs. 74±19ml/min; p=0.475) and no histological differences in protocol biopsies were observed among patients with asymptomatic CMV reactivation vs those without CMV reactivation. ConclusionsDue to the high asymptomatic CMV reactivation incidence in patients who received thymoglobulin induction, our results suggest that valganciclovir prophylaxis may be advantageous in CMV seropositive renal transplant recipients after low dose thymoglobulin induction. A preemptive strategy appeared to significantly reduce the likelihood of CMV disease in both groups. Rejection risk and negative impact in renal function associated with asymptomatic CMV reactivation was not found in our series.

Intensity of Induction Regimen and Outcomes Among Adults with Ph+ ALL Undergoing Allogeneic Hematopoietic Stem Cell Transplantation

Introduction Tyrosine kinase inhibitors (TKIs) have facilitated the development of low intensity induction regimens for Philadelphia-chromosome positive (Ph+) ALL. Whether the use of a low intensity induction regimen prior to allogeneic hematopoietic stem cell transplant (HSCT) impacts post-HSCT outcomes is not known. We studied patients with Ph+ ALL receiving HSCT in CR1 at our center to assess the impact of induction treatment intensity on post-HSCT outcomes. Methods We identified consecutive adult patients with Ph+ ALL who underwent HSCT in CR1 between January 1, 2010 and April 31, 2021. Induction therapy was classified as low intensity (TKI, corticosteroid, with or without vincristine) or high intensity (all others). Pre-HSCT measurable residual disease negative (MRDneg) status was determined by BCR::ABL1 RT-PCR and/or via multi-parameter flow cytometry with sensitivity of at least 4.7 and 4 logs respectively. Comparisons between variables were assessed using the Fisher exact (categorical) or Wilcoxon rank-sum (continuous) tests. Overall survival (OS) was defined as time from HSCT to death. Disease-free survival (DFS) was defined as time from HSCT to hematologic relapse or death. The OS and DFS analyses were performed using Cox proportional hazards regression, and differences were assessed using the log rank test. The cumulative incidence of relapse (CIR) was compared between the high versus low intensity induction therapy groups from the time of transplant, with non-relapse mortality (NRM) a competing event. Results A total of 87 patients with Ph+ ALL transplanted in CR1 were identified. Patients in the low intensity induction cohort (n=44, 51%) were older (median 60 vs 47 yrs, p<0.01) and more frequently diagnosed after 2015 (73% vs 33%, p<0.01) compared to patients in the high intensity cohort (n=43, 49%). Clinical and pathologic characteristics including initial white blood cell count, presence of central nervous system disease, BCR::ABL1 transcript type (p190 vs. p210), and presence of additional cytogenetic abnormalities did not differ between groups. There was no difference between the low and high induction intensity cohorts in the proportion of patients requiring a salvage regimen to achieve CR1 (14% vs. 16%, p=0.77). Following induction, molecular MRDneg status was similar in the low and high intensity cohorts (54% and 52% respectively, p=0.99). Most patients proceeded directly to alloHSCT after their initial treatment regimen with similar time to alloHSCT from Ph+ ALL diagnosis in both low and high intensity groups (4 vs. 5 months, p=0.93). Patients receiving low intensity induction were numerically more likely to receive a reduced intensity conditioning (RIC) HSCT (39% vs. 19%, p=0.06). At a median follow-up of 21 months from HSCT, there was no difference between low and high intensity induction with respect to 2-yr DFS (58% vs. 56%, p=0.58), 2-yr OS (62% vs. 63%, p=0.46), 2-yr CIR (9% vs. 17%, p=0.78), and 2yr NRM (33% vs. 29%, p=0.54). A comparison among the low intensity subgroup receiving myeloablative conditioning (MAC) vs. RIC showed no statistically significant difference in OS (HR, 1.02; 95% CI, 0.41-2.54; p=0.97). We segmented patients by pre-HSCT induction intensity and transplant conditioning intensity in the following categories: high intensity induction with MAC HSCT, high intensity induction with RIC HSCT, low intensity induction with MAC HSCT, and low intensity induction with RIC HSCT. Log-rank tests across the four groups showed no significant difference in 2-year DFS (p=0.40), 2-year OS (p=0.19), 2-year CIR (p=0.21), and 2-year NRM (p=0.76). Conclusion Among adult Ph+ ALL patients transplanted in CR1, the intensity of initial induction regimen does not appear to impact post-HSCT outcomes supporting the use of low intensity induction regimens prior to curative HSCT. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Personalization of Induction Therapy for Pediatric AML to Ara-C+Dauno+ Etoposide (ADE) or Clofarabine+Ara-C According to a Polygenic Ara-C SNP Score- ACS10

Acute myeloid leukemia (AML) is a heterogenous disease with overall suboptimal outcome. Although chemotherapy regimens that include cytarabine (ara-C) induce remission in a majority of pediatric AML patients, approximately 30% relapse and subsequently have very dismal outcome. Ara-C is a prodrug requiring activation to ara-CTP which induces leukemic cell death. Thus, inter-patient variation in each patient's ability to activate ara-C is a significant contributor to clinical outcomes. We recently performed a comprehensive pharmacogenomics evaluation of SNPs in ara-C metabolism pathway genes and developed a polygenic ara-C 10-SNP genotype (ACS10) score based on association with leukemic intracellular ara-CTP levels and clinical outcome (Elsayed et al, 2022, JCO1). Our results demonstrated that patients with low ACS10 score had poor outcomes when given standard induction including low-dose ara-C, daunorubicin and etoposide (ADE); however their outcomes were much better by augmenting therapy with either an increased dose of ara-C or the addition of gemtuzumab ozogamicin1. Conversely, patients with a high ACS10 score fared worse when given high-dose ara-C than low ara-C dose-based ADE induction (LDAC). These results suggest that pediatric AML patients may benefit from pharmacogenetic personalization of ADE therapy according to their ACS10 scores. Additionally, these results motivate research regarding the utility of ACS10 for pharmacogenetic personalization of other therapies for pediatric AML. Clofarabine is another nucleoside analog that inhibits both DNA polymerase as well as ribonucleotide reductase, thus enhancing the activity of ara-C. Recent data from the AML08 clinical trial [NCT00703820] has shown promising results with use of clofarabine with cytarabine during remission induction in pediatric AML patients.2 Therefore, we evaluated the association of ACS10 score with outcomes among 91 patients randomly assigned standard ADE induction on the AML02 clinical trial (LDAC arm) [NCT00136084] and 117 patients randomly assigned an induction of clofarabine and ara-C (Clo+Ara-C arm) on the AML08 trial [NCT00703820] (Figure 1A shows the study design). 5-year event-free survival (EFS) and overall survival (OS) of patients treated with ADE improved with increasing ACS10 score; however, for patients treated with Clo+Ara-C, improvement with increasing ACS10 score was not observed (OS shown in Figure 1A). This differential outcome association pattern suggests that thresholding the ACS10 score at 0 could be used to classify patients into low (<=0) and high (>0) ACS10 groups. Patients within low ACS10 score group had a better outcome with Clo+AraC whereas the high ACS10 score patient group fared better with ADE. In particular, there is significant improvement in EFS and OS within the low-ACS10 score patients when treated with Clo+Ara-C as compared to ADE (Clo+AraC vs. ADE; EFS HR=0.45, 95% CI: 0.23-0.82; p=0.01; OS HR=0.45, 95% CI: 0.19-0.93, p=0.028; Figure 1B). In contrast, patients with a high ACS10 score had worse EFS and OS with Clo+AraC induction than with ADE induction (EFS HR= 1.84, 95% CI: 0.99-3.41, p=0.05; OS HR= 2.40, 95%CI: 1.13-5.13; p=0.02, Figure 1B). These results are unlikely to suffer from a strong historical comparison bias because there are not statistically significant differences in the outcomes of the randomly assigned therapies of the AML02 and AML08 trials as well as outcome by the clinical trial (EFS/OS of each arm of the two trials as well as between AML02 and AML08 trials; p=0.8, data not shown). In summary, consistent with our recent report, these results show that for patients with Low-ACS10 genetic score prognosis is poor with standard ADE induction. However, therapy augmentation options such as Clo+AraC, ADE with high-dose Ara-C, and ADE+gemtuzumab may improve the prognosis. This calls for an action on using preemptive genotyping for selection of the most effective induction 1 chemotherapy regimen to achieve maximum clinical benefit. References. 1. Elsayed AH, et al: Polygenic Ara-C Response Score Identifies Pediatric Patients With Acute Myeloid Leukemia in Need of Chemotherapy Augmentation. JCO 2022, PMID:34990262 2. Rubnitz JE, et al: Clofarabine Can Replace Anthracyclines and Etoposide in Remission Induction Therapy for Childhood Acute Myeloid Leukemia: The AML08 Multicenter, Randomized Phase III Trial. JCO 2019, PMID:3124652 Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

5.8-GW Discharge Brick for Linear Transformer Driver

Discharge brick is the basic discharge unit of fast linear transformer driver (LTD). It is important to reduce the scale and cost of LTD device by increasing discharge current and brick power of the brick. In this article, a discharge brick is designed for LTD, including a 200-kV three-electrode field-distortion gas switch (TFGS) and two 100-kV/100-nF capacitors. At the same time, a low inductance liquid resistor load (LRL) is designed for simulating the actual working condition of discharge brick in LTD cavity. The brick inductance is tested with 200 nH, and when operating voltage at ±100 kV, the peak discharge current and brick power can reach 62 kA and 5.8-GW, respectively. The trigger test of 10 000 shots with different switch structure has been proceeded, and the pre-fire rate is lower than 0.3%.

Research on a novel HTS double pancake coil based on CORC: used for kA-level SMES of accelerator

Large-scale complex needs high performance SMES system with 5 kA-level current carrying and kA s−1 current ramping rate (such as particle accelerator complex), the inductance of which should be as small as possible (≪1 H) to reduce the terminal voltage and realize ideal energy evacuation. This paper introduces the world’s first application of double pancake (DP) coil with conductor on round core cable (CORC) cable, which can be a unit of MJ-level SMES system with a total inductance of 125 mH and 4 kA current carrying (@30 K, 4 T). The combination of low inductance and high current capacity guarantee the safety during kA s−1 operating condition. The CORC wound with highly anisotropic YBCO tape can realize quasi-isotropy with critical properties. The performance of the CORC with 11 layers and three tapes in each layer has been fully validated with excitation test at 77 K and the critical current can reach 2906 A at 77 K, self-field. The skeleton of the DP coil is specially designed with semi-circular spiral groove and the climbing-layer area is supported by two symmetrical blocks, which can provide reasonable support to the CORC cable. The measured critical current of DP coil can realize 1750 A at 77 K (theoretical value is 1800 A). It means that the coil winding method is feasible to avoid performance degradation during winding. The DP coil based on CORC cable is fully suitable for the SMES system which needs to realize ∼4 kA current carrying and fast energy conversion. It also provides a good practice for the engineering application of CORC cable.

Si-IGBT and SiC-MOSFET hybrid switch-based 1.7 kV half-bridge power module

• Design guidelines, fabrication process, and evaluation of a 1.7-kV and 300-A multi-chip half bridge power module using the novel Si-IGBT and SiC-MOSFET hybrid switch in each switch position. • The module achieves its maximum DC current rating with a 6:1 current ratio of Si to SiC. • A novel custom-designed TPG-encapsulated metal base plate is proposed. • Silver clips for top-side interconnect in the module, facilitating a wire bond-less interconnection, high reliability, and low power loop inductance. • High thermal dissipation capability while maintaining a near-isolated thermal path for the SiC MOSFET to operate at a higher temperature than the Si-IGBT. This paper informs the design guidelines, fabrication process, and evaluation of a 1.7-kV and 300-A multi-chip half bridge power module using the novel Si-IGBT and SiC-MOSFET hybrid switch in each switch position. The module achieves its maximum DC current rating with a 6:1 current ratio of Si to SiC. This high current ratio yields significant cost savings compared to an all-SiC power module. The module employs high-reliability silver clips, which replaces conventional wire bonds for top-side interconnection, to partly enable a low power loop inductance of 12.38 nH. A novel thermal pyrolytic graphite-encapsulated metal baseplate is key to reducing the thermal coupling among the adjacent Si and SiC die, enabling higher junction temperature for SiC die relative to the Si die.

A PCB-Embedded 1.2 kV SiC MOSFET Half-Bridge Package for a 22 kW AC–DC Converter

This article presents the design and analysis of a double-side-cooled printed circuit board (PCB) embedded silicon carbide (SiC) MOSFET half-bridge package with low loop inductances and an integrated gate driver. The 1.2 kV SiC MOSFET dies used in the half-bridge package are embedded in the PCB using AT&S's patented technique. The dies are cooled and electrically connected to traces in the PCB through copper-filled microvias. The design methodology accounts for both electrical and thermal performance, limiting the power-loop inductance to 2.3 nH and the maximum package temperature to less than the 175 °C limit. The integration of the gate drive circuitry allows for a high power density and 2.2 nH gate-loop inductances. At 0.12 K/W, the measured junction-to-case thermal resistance with double-sided cooling is 57% lower than that of a TO-247 package. Under similar operating conditions, the PCB-embedded half-bridge package also achieves a 5.6 times lower voltage overshoot and a 0.5% higher peak efficiency than a TO-247-based half-bridge. This article reports the first demonstration of PCB-embedded 1.2 kV SiC MOSFET packages in buck, boost, and ac–dc converters. The prototype three-phase ac–dc converter for an electric vehicle on-board charger is composed of six PCB-embedded half-bridge packages and achieves an efficiency of 98.2% and a power density of 182 W/in <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> .

Printed circuit board embedded power semiconductors: A technology review

Embedding power semiconductor devices into printed circuit boards (PCB) provides several benefits compared to conventional packaging technologies. Integrating the semiconductor dies into the circuit board reduces the converter size. This results in short current loops, enabling low interconnection resistances and parasitic inductances. Both contribute to a higher system-level efficiency, as conduction and switching losses are reduced. Moreover, the use of thick Cu substrates allows efficient heat removal, due to a low thermal resistance. Therefore, PCB embedding has received a lot of attention in the power electronics community for more than a decade. This article aims to provide a comprehensive review of the scientific literature on the topic ranging from basic fabrication technology over module or system-level demonstrators for electrical and thermal testing to reliability studies. Performance indicators, such as the commutation loop inductance Lσ, the chip area independent thermal resistance Rth × Achip, allow a comparison of different approaches and benchmarking with conventional power modules. Several publications report stray inductances below 1 nH and chip area independent thermal resistances in the range of 20…30 mm²K/W.

An Online Monitoring Method for Single Aluminum Electrolytic Capacitor in the DC Bank of Single-Phase Inverter Based on the Rogowski Coil

State-of-the-art capacitor online monitoring methods are designed for the whole dc bank. The capacitance or equivalent series resistance of the dc bank, as an aging indicator, is obtained by the sensors installed at the dc terminal, or derived from the state equation of the system. The difference of capacitor parameters from manufacturing and the arrangement of the dc bank will result in uneven thermal stress for the capacitors. Due to the restriction of the low stray inductance specification and high power density requirement, the traditional online monitoring circuits are hard to be designed for the single capacitor in the dc bank. In this article, a Rogowski coil based online monitoring circuit has been designed for the single capacitor in the dc bank. A new aging criterion has been established for aluminum electrolytic capacitors based on the accelerated aging test. To achieve a compact integration design, a six-layer printed-circuit-board-type Rogowski coil is designed under an optimized frequency. A 2-kW single-phase inverter is built to verify the theoretical analysis and practical performance of the monitoring circuit.

The Generation of Intense-Relativistic-Microsecond Electron Beams From a High-Energy-Density Marx Generator With Waveform Modification

Intense electron beams with pulse duration on the level of microseconds have been utilized in a number of areas, including the production of free electron laser, material surface modification, and high-energy-density physics research. The high-voltage pulse forming technology based on metal oxide varistors (MOVs) has been verified to be an effective way to produce quasi-square pulses in recent years. In this article, a high-energy-density Marx generator with output waveform modified by a flat-top compensation LC filtering branch and a low inductance MOV folding structure was designed and tested to generate microsecond pulses. Experimental results show that a quasi-square pulse with a voltage amplitude of more than 500 kV and a pulsewidth of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1~\mu \text{s}$ </tex-math></inline-formula> was obtained on a dummy load of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$50~\Omega $ </tex-math></inline-formula> . Further experimental research was carried out using a magnetically insulated coaxial diode (MICD) electron beam diode, and as a result, a relativistic electron beam with an energy of 550 keV, a current of 8.3 kA, a rise time of less than 40 ns, and a flat-top of about 600 ns was produced. The Marx generator with a modified waveform has the advantages of simple design, compact construction, and high-quality flat-top, which is a good platform for the generation of intense microsecond electron beams.

AML-165 Clinical Outcomes of Patients With FLT3-Mutated Acute Myeloid Leukemia (AML): A Single-Center Retrospective Review

Fms-like tyrosine kinase-3 (FLT3) gene activating mutations predominate in AML, with internal tandem duplication (ITD) in 25 to 35% and point mutations in 5 to 7% of patients with normal karyotype. They associate with shorter relapse-free survival (RFS) and inferior outcome. To examine targeted FLT-3 mutations therapy during induction chemotherapy (IC) of AML. We reviewed all FLT3 mutated AML (both ITD and point mutations in the tyrosine kinase domain (TKD)) patients treated with FLT-3 targeted therapy during IC from March 2013 till December 2021. 28 patients (de novo AML=22, APL=6) with FLT3 mutated AML were identified. Fit patients received IC with fludarabine, cytarabine, and idarubicin (FIA) or IA (3+7 regimen). Older patients received hypomethylating agents (HMA) alone or with venetoclax (Ven). All received IC with FLT3 inhibitors (FLT3I, gilteritinib). All 6 APL patients achieved CR with arsenic trioxide (ATO) and all-trans-retinoic acid (ATRA). Analysis included overall response rate (ORR), complete response (CR), and relapse-free survival (RFS). 14 patients (50%) were men. Races included Whites (n=9), Blacks (n=6), Hispanics (n=8) and Others (n=5). The median age was 54 years (range, 20-68). 20 (71.40%) had ITD mutation, 4 (14.20%) had TKD mutation and 4 had both. 15 had NPM1 and 3 DNMT3A mutations. 14 patients had intermediate and 8 adverse risk AML (ELN). Of the AML patients 14 received standard, IC (FIA=8, IA=2, FIA+FLT3I=4), and 12 (85%) achieved CR. Unfit patients received (HMA alone=2, HMA+ Ven=4, HMA+Ven+FLT3I=1, HMA+FLT3I=1). The ORR was 60% with 50% CR. One FIA dead during IC. Three AML patients (10.70%) had allogeneic stem cell transplantations (ASCTs) and had remained in CR. Two non-ASCT were treated with HMA and one with FLT3I maintenance remaining in CR. 4 patients (14.20%) died in remission. Median relapse-free survival (RFS) was 360 days (range, 218-669). The median RFS for non-ASCT patients was 240 days (range, 195-405). Historically RFS in FLT-3 AML is 120 days. IC with FLT3I is highly effective with low induction mortality. Response duration was shorter in the non-ASCT group. In FLT-3 AML ASCT ineligible patients, maintenance therapy may reduce relapse risk.

Influence of impulse magnetic fields of extremely low frequencies on H2O2- and Fe2+-induced free radical lipid oxidation in liposomal suspensions

Background: For a long time, special attention in experimental biology and medicine is paid to free radical processes involving reactive oxygen species. In electromagnetic biology, the interest in free radical oxidation in biological membranes has increased significantly due to the discovery of spin mechanisms of magnetic fields on free radical processes. In the present day, these mechanisms are considered to be key in the processes of magnetoreception in living organisms. Liposomes, as the simplest models of biological membranes, are often used to study the primary mechanisms of action of different factors on the structural and functional properties of membranes. However, the influence of ecological significant extremely low-frequency magnetic fields on free radical oxidation in liposomal suspensions has not been studied enough. Objectives: The elucidation of the peculiarities of the influence of the extremely low frequency pulsed magnetic fields (ELF PMF) on H2O2- and Fe2+-induced peroxidation of natural phospholipids in liposomal suspensions. Materials and methods: The liposomal suspensions in phosphate buffer pH=7.4 were used. According to the literature and own results on light scattering the average diameter of liposomes was about 500Å. Ultra-weak chemiluminescence of liposomal suspensions was recorded using a device that operated in the mode of single photons counting. It consisted of a light-insulated cuvette unit where the test samples were placed, as well as a temperature sensor and a solenoid, which was used to create the PMF. Optical contact of the test samples with the photoelectron multiplier was carried out using a light guide. The recording system consisted of a broadband photomultiplier tube detector — FEU-130, which was at a temperature of –20°C. The pulse analyzer AI-256 was used to separate the useful signal that corresponded to the registration of single chemiluminescence light quanta. The voltage on the photomultiplier tube detector was applied in the range of current-voltage characteristics of this detector, in which a random voltage fluctuation had a minimal effect on the measurement of the useful signal. The number of light quanta that were recorded for defined time intervals characterized the overall intensity of the process of free radical oxidation of lipids in the experimental samples. The pulsed magnetic field was created using a solenoid coil located in the cuvette part. PMF was created using a serial generator G6-28. The magnetic field pulses were rectangular in shape with variable polarity for a period of oscillations. The induction of PMF was monitored using microteslameter G-79. The series of extremely low frequencies (5–80 Hz) and induction (5–500 μT) of PMF was chosen due to their environmental and physiological significance. Results: PMF of different frequencies with induction of 5 and 50 μT did not affect (p&gt;0.05) H2O2- and Fe2+-induced lipid oxidation in liposomal suspensions. Statistically significant changes (p&lt;0.05) were revealed only when liposomal suspensions were exposed to PMF with induction of 500 μT. It was found that the action of PMF with the frequency of 8 Hz 500 μT significantly inhibited H2O2-induced and enhanced Fe2+-induced chemiluminescence. This effect is associated with inhibition of the decomposition and with the accumulation of phospholipid hydroperoxides, which decompose and recombine in the presence of Fe2+ ions, which is accompanied by stronger chemiluminescence. The study of the dependence of the dynamics of the chemiluminescence intensity on the frequency of the PMF indicates the presence of a certain dependence of the effects in the range of up to 30 Hz. However, the inhibitory effect of PMF for the H2O2-induced oxidation phase is not always accompanied by a statistically significant increase in the amplitude of Fe2+-dependent light flash of chemiluminescence that indicates the general inhibitory effect of PMF at a certain frequency. Conclusions: PMF of extremely low frequencies statistically significantly affects the free radical oxidation in liposomal suspensions only at inductions exceeding several hundred microteslas. This indicates the effect of PMF on free radical processes for the conditions of the selected membrane model is realized mainly through spin interactions that determine the recombination of free radicals. The decrease of induction by one or two orders of magnitude, as well as increasing in frequency of the PMF above 50 Hz, leads to a decrease in the effectiveness of the influence of this physical factor on the intensity of lipid-free radical oxidation in liposomal suspensions. The most sensitive to the influence of ELF PMF is the phase of H2O2-induced free radical oxidation of lipids.

Integration of superconducting fault current limiter with solid-state DC circuit breaker

The onboard direct current (DC) system in electric aircraft could face a severe fault current, which is tens of times the nominal current in a short-circuit fault. It is critical to limit the fault current and clear the fault within a few milliseconds to prevent any damage to the DC system. A protection method using a resistive superconducting fault current limiter (SFCL) with a solid-state DC circuit breaker (SSCB) to manage the DC short-circuit fault is proposed and experimentally verified. A bifilar SFCL coil prototype with two types of connection to achieve low and high inductance is designed and tested, which reduces the fault current considerably from 2000 A to below 1000 A. The performance when integrating the low and high inductance SFCL with a solid-state DC circuit breaker are investigated. It is found that when integrating the SFCL with the SSCB, a high voltage is induced across the high inductance SFCL during current interruption tests. In terms of reliability and durability, the low inductance SFCL is preferred to integrate with the SSCB. The experimental results show that the low inductance SFCL can be an effective solution to protect the DC system from severe fault currents and then SSCB can rapidly and reliably interrupt the fault current at 1000 A.© 2017 Elsevier Inc. All rights reserved.