Search

The sequential using of topology optimization and AM (additive manufacturing) can generate and fabricate superior-performance yet lightweight magneto-structural components. In this paper, a magneto-structural topology optimization method is proposed considering AM constraints to improve the design manufacturability of optimized designs. The design problem is formulated with the weighted combination of magnetic compliance and mechanical compliance as a single objective subjected to two types of manufacturing constraints and the volume fraction constraint. Two important AM constraints are in a sequential manner incorporated into the topology optimization model, in which the overhang angle constraint is followed by the maximum length scale constraint. Corresponding sensitivities of the objective and constraints are derived, and the optimization problem is solved by the method of moving asymptotes. Two numerical examples and a practical conceptual design of linear motor rotor structure are systematically investigated to demonstrate the effectiveness of the proposed method.

The reliability of nanoscale electronic systems is important in various applications. However, they are becoming increasingly vulnerable to atmospheric neutrons. This research conducted spallation neutron irradiations on a Xilinx Zynq-7000 system on a chip using the China Spallation Neutron Source. The results were analyzed in combination with a Monte Carlo simulation to explore the impact of atmospheric neutrons on the single event effects of the target system on chip. Meanwhile, the contribution of thermal neutrons to the chip’s single event effect susceptibility was also assessed. It was found that absorbing thermal neutrons with a 2 mm Cd sheet can protect against the single event effect on the system on the chip by about 44.4%. The effects of B and Hf elements, inside the device, on a single event effect of the Xilinx Zynq-7000 system on chip were evaluated too. Additionally, it was discovered that 10B interacting with thermal neutrons was the primary cause of the thermal neutron-induced single event effect in the system on chip. Although Hf has a high neutron capture cross section, its presence does not significantly affect the sensitivity to single event effects. However, during atmospheric neutron irradiation, the presence of Hf increases the possibility of depositing the total dose in the tested chip.

As a key area in the Yellow River basin for sand control and management, the land change process in the Hobq Desert plays a crucial role in keeping the river and desert ecosystems and promoting the construction of ecological civilization in human systems. Based on multi-temporal remote sensing from 1991 to 2019 in the Hobq Desert along the Yellow River section, this study selected spatial statistical methods (land-use monitoring and landscape metrics) to examine land-use change dynamics. Then, we evaluated habitat quality using the InVEST model and quantitatively analyzed the factors causing spatial changes in habitat quality using geographic detectors. Finally, this paper predicted the pattern of land use and habitat quality in 2030 using the PLUS model. The results reveal that (1) from 1991 to 2019, the total area of forest grassland increased by 3572.5 km2, providing the most vegetation cover, and the sandy land and water area decreased continuously, while the cultivated land and construction land increased. There were 38.01% conversions of land types, with the land-use dynamic decreasing the greatest in sandy land (−12.66%) and increasing the greatest in construction land (9.26%); the comprehensive land-use dynamics were the highest in 2010–2019 (1.68%), which was the most active stage during our study period. (2) Both of the landscape indices NP and PD showed “N” type fluctuations during 1991–2019, and CONTAG and LSI rose from 69.19% to 70.29% and 36.01% to 38.89%, respectively, indicating that the land-use degree of landscape fragmentation increased, landscape connectivity turned better, and landscape dominance was enhanced, balanced, and developed evenly in overall landscape type. (3) From the overall region analysis, the average habitat quality in 1991, 2000, 2010, and 2019 was 0.3565, 0.5108, 0.5879, and 0.6482, respectively, with the overall habitat value showing a gradually increasing trend. Spatially, the habitat quality along the Yellow River section of the Hobq Desert has a certain regularity, and the overall pattern there is high in the south and low in the north, high in the east and west, and low in the middle. (4) The change in land use between 2019 and 2030 is similar to the previous period, but the change rate is generally lower. The habitat quality improved significantly, with the growth of high and medium habitat quality.

Cerebral ischemia/reperfusion (I/R) injury is the result of ischemic stroke, a serious threat to public health. I/R injury can damage the blood-brain barrier (BBB), adversely affecting the brain environment and aggravating the injury. Cyclo-(Phe-Tyr) (sparganin C, SC) is a small molecule derived from the Chinese yam

N6-methyladenosine (mThe relationship between lncRNAs and 21 mA substantial number of positive correlation events across 33 cancer types were found. Moreover, cancer-specific lncRNAs were associated with tissue specificity, and cancer-common lncRNAs were conserved in cancer-related biological function. In particular, the mIn summary, the results from this paper will provide a valuable resource that guides both mechanistic and therapeutic roles of m

Fast neutrons and gamma-ray imaging detection is an effective way to detect and identify radioactive material in the field of nuclear security. A compact coded aperture imaging (CAI) camera was designed to be sensitive to both gamma and neutron radiation based on plastic scintillators and multi-pixel photon counters (MPPC). MPPCs coupling with the 13 × 13 pixelated plastic scintillators one-to-one were utilized to reduce the scale of the CAI system while maintaining good positional performance. The symmetric charge division (SCD) circuit was adopted to reduce the 169 signals output from the MPPC array to 26. Each waveform was collected and processed with four Domino Ring Sampler 4 (DRS4) chips and two 16-channel analog-to-digital converter (ADC) modules. As the pulse shapes of fast neutrons would be broadened after elastic scattering multiple times in the scintillators, the Anger-Logic method was applied to eliminate multiple elastic scattering events so that good pulse shape discrimination (PSD) performance can be achieved. The imaging and detection ability of the camera was evaluated using the 241Am-Be (5.9 × 105 n/s) neutron source and 137Cs (370 MBq) gamma source. The camera can be used to detect fast neutrons (0.5–10 MeV) and gamma rays (0.2–2.5 MeV). Furthermore, it can implement efficient neutron/gamma PSD capabilities in the mixed-field environment. The figure of merit (FOM) of the camera calculated at 400keVee energy cut is 0.93. A compact MPPC-based CAI camera was designed to detect and discriminate fast neutrons and gamma rays. Its good PSD performance was well suited to distinguish fast neutrons from gamma rays in a dual-particle environment. The portable design makes it promising for complex monitoring scenarios in nuclear security.

Diabetes seriously endangers public health and brings a heavy economic burden to the country. Inflammation is one of the main inducing factors of type-2 diabetes (T2D) and may cause some complications of diabetes, such as diabetic encephalopathy and peripheral neuropathy. In-depth research and development of drugs to cure diabetes and complications are of great significance. Pueraria lobate is a medicinal herb used in several countries to treat many diseases. Here, two new polysaccharides (PLB-1-1 and PLB-1-2) were isolated and purified from the root of Pueraria lobata with molecular weights of 9.1 × 103 Da and 3.8 × 103 Da, respectively. The structure was evaluated by monosaccharide composition, GC-MS and NMR spectroscopy. It was determined that PLB-1-1 comprised →4)-α-D-Glcp-(1→, α-D-Glcp-(1→, →6)-β-D-Galp-(1→, →3)-α-L-Araf-(1→, →3,6)-β-D-Manp-(1→ and →4,6)-β-D-Manp-(1→, and PLB-1-2 consisted of →4)-α-D-Glcp-(1→, β-D-Glcp-(1→, →4,6)-β-D-Glcp-(1→, →3,6)-β-D-Manp-(1→ and α-L-Fucp-(1→. Furthermore, both PLB-1-1 and PLB-1-2 showed anti-inflammatory and inhibitory activities of α-glucosidase and α-amylase in vitro. Therefore, the new polysaccharides, i.e., PLB-1-1 and PLB-1-2, may be considered candidates for the treatment of diabetes and its related complications.

Ischemic stroke (IS) caused by cerebral arterial occlusion is the leading cause of global morbidity and mortality. Cellular oxidative stress and inflammation play a vital role in the pathological process of neural damage in IS. It is necessary to develop functional food or drugs, which target neuroinflammation and oxidation mechanisms against IS. The molecule compound aloe-emodin (AE) is derived from aloe and rhubarb. However, the exact mechanism of the pharmacological action of AE on IS remains unclear. Here, for aiming to demonstrate the mechanism of AE, our study explored the middle cerebral occlusion reperfusion (MCAO/R) rats in vivo, oxygen and glucose deprivation reperfusion (OGD/R), and lipopolysaccharide (LPS)-stimulated cells in vitro. We found that AE significantly improved the infarct size and behavioral score of MCAO/R rats, decreased the expression of TNF-α, MDA, LDH, Caspase 3, and increased the expression of SOD, Bcl-2/Bax. Liquid chromatography-mass spectrometry (LC/MS) results showed that AE could penetrate the blood-brain barrier in the sham group and MCAO/R group. In vitro, AE significantly protected SH-SY5Y cells from the insult of OGD/R and reduced the production of inflammatory cytokines in BV2 cells stimulated by LPS. In vivo and in vitro, western blot analysis results showed that AE significantly increased the expression of PI3K, AKT and mTOR proteins. In addition, AE significantly decreased NF-κB protein expression in BV2 cells. The use of AKT-specific inhibitor MK-2206 2HCL to inhibit AKT expression can block the protective effect of AE on SH-SY5Y cells subjected to OGD/R insults. Overall, our study suggests that AE protected against cerebral ischemia-reperfusion injury probably via the PI3K/AKT/mTOR and NF-κB signaling pathways. Thus, these results indicated that AE could be a promising first-line therapy for preventing and treating ischemic stroke and can be used as functional food.

Neuronal damage after ischemic stroke (IS) is frequently due to ferroptosis, contributing significantly to ischemic injury. However, the mechanism against ferroptosis in IS remained unclear. The aim of this study was to investigate the potential mechanism of Danhong injection (DHI) and the critical transcription factor SATB1 in preventing neuronal ferroptosis after ischemic stroke in vivo and in vitro. The results showed that DHI treatment significantly reduced the infarct area and associated damage in the brains of the pMCAO mice, and enhanced the viability of OGD-injured neurons. And several characteristic indicators of ferroptosis, such as mitochondrial necrosis and iron accumulation, were regulated by DHI after IS. Importantly, we found that the expression and activity of SATB1 were decreased in the pMCAO mice, especially in neuron cells. Meanwhile, the SATB1/SLC7A11/HO-1 signaling pathway was activated after DHI treatment in ischemic stroke and was found to improve neuronal ferroptosis. Inhibition of SATB1 significantly reduced SLC7A11-HO-1 and significantly attenuated the anti-ferroptosis effects of DHI in the OGD model. These findings indicate that neuronal ferroptosis after IS can be alleviated by DHI through SATB1/SLC7A11/HO-1 pathway, and SATB1 may be an attractive therapeutic target for treating ischemic stroke.

Ischemic/reperfusion (IR) can cause adverse reactions including apoptosis, oxidative stress, and inflammation, but the existing therapeutic strategies have been limited. Moreover, the regulation of microglia plays an important role in brain injury after reperfusion. Hence, it is imperative to find new and effective drugs for modulating microglia to treat IR brain injury. Cyclic peptide compound cyclo-(Phe-Tyr) (Sparganin C, SC) is a compound isolated from Sparganii Rhizoma. However, the protective effects of SC on the central nervous system are rather unclear. In an attempt to elucidate the protective effects and mechanism of SC on cerebral damage induced by the IR, we used a middle cerebral artery occlusion reperfusion (MCAO/R) model in rats and discovered that SC significantly decreased the size of cerebral infarcts, improved neurological scores, and blocked inflammatory and oxidative factor release. Using RNA-Seq and metabolomics association analyses, SC was shown to have a protective impact through the JUNB and SOX5-related pathways. Metabolomic analysis revealed twenty-eight differentially expressed biomarkers. In addition, the detection of SC content in brain tissue using LC/MS revealed that SC had blood-brain barrier penetration. To investigate the mechanism, we established an in vitro BV2 cell oxygen-glucose deprivation/reperfusion (OGD/R) model and used siRNA as well as an inhibitor. The protective effects of SC were dependent on the JUNB and SOX5 to inhibit inflammation and apoptosis in microglia. Our findings revealed for the first that SC against IR injury by reducing inflammation and apoptosis while simultaneously acting as potential therapeutic lead compound for ischemic stroke.

Ischemic stroke (IS), as a leading cause of disability worldwide, affects intestinal bacterial communities and their metabolites, while recent discoveries have highlighted the importance of the intestinal microflora in the development of IS. Systematic investigations of complex intestinal bacterial communities and their metabolites during ischemic brain injury contribute to elucidate the promising therapeutic targets for IS. However, the associations between intestinal microbiota and related circulating metabolic processes in IS remained unclear. Hence, to identify the changed microflora and their metabolites in IS of NaoMaiTong (NMT), an effective clinical medication, we established the middle cerebral artery occlusion/reperfusion (MCAO/R) model using conventionalized and pseudo-germ-free (PGF) rats. Subsequently, we systematically screen the microflora and related metabolites changing in IS via an integrated approach of cecal 16S rRNA sequencing combined with plasma metabolomics. We found that NMT relied on intestinal flora to improve stroke outcome in conventionalized rats while the protection of NMT was reduced in PGF rats. Total 35 differential bacterial genera and 26 differential microbial metabolites were regulated by NMT. Furthermore, L-asparagine and indoleacetaldehyde were significantly negatively correlated with Lachnospiraceae_UCG.001 and significantly positively correlated with Lachnoclostridium. Indoleacetaldehyde also presented a negative correlation with Lactobacillus and Bifidobacterium. 2-Hydroxybutyric acid was strongly negatively correlated with Ruminococcus, Lachnospiraceae_UCG.001 and Lachnospiraceae_UCG.006. Creatinine was strongly negatively correlated with Akkermansia. In summary, the research provided insights into the intricate interaction between intestinal microbiota and metabolism of NMT in IS. We identified above differential bacteria and differential endogenous metabolites which could be as prebiotic and probiotic substances that can influence prognosis in stroke and have potential to be used as novel therapeutic targets or exogenous drug supplements.

Acupuncture is an effective therapy for ischemic stroke, which has been widely used in China and gradually accepted in more countries and regions recently. In addition, Chinese medicine also plays an important role in stroke treatment, among which NaoMaiTong (NMT) is an example of an effective herbal formula for the treatment of stroke. A therapeutic strategy that combines acupuncture and medicine was widely used in stroke patients. However, the synergistic influences and mechanisms of combined acupuncture and medicine on ischemic stroke have not yet been entirely elucidated.The purpose of this study is to explore whether acupuncture and medicine combination treatments can produce synergism by using NMT, a clinically effective Chinese medicinal formula for the treatment of ischemic stroke for decades and has been demonstrated to be effective against ischemic brain injury, as a probe. Meanwhile, the potential mechanisms were investigated via cecal microbiome and plasma metabolomics to provide more strategies and basis for acupuncture-medicine combination for stroke.Adopted middle-cerebral artery occlusion/reperfusion (MCAO/R) rat models, the effect for the stroke of the combination treatment consisting of acupuncture and NMT was evaluated by detecting neurological issues, cerebral infarct dimensions, levels of inflammatory factors (IL-6, IL-1β, TNF-α) and oxidative stress factors (SOD, MDA) and brain-derived neurotrophic factor (BDNF). Subsequently,16S rRNA gene sequencing and LC/MS-based metabolomic analysis were utilized to explore the characteristics of cecal-contents microecology and plasma metabolic profile, respectively. Finally, the correlation between intestinal microecological characteristics and plasma metabolic characteristics was analyzed to explore the potential mechanism of the acupuncture-NMT combination.The efficacy of acupuncture-NMT therapy was more effective than a single treatment on ischemic stroke, with more effectively reduced infarct sizes, improved neurobehavioral deficits, and alleviated oxidative stress and inflammatory responses. Besides, the combination therapy not only adjusted gut microbiota disturbances by enriching species diversity, reducing the abundance of pathogenic bacteria (such as Escherichia-Shaigella), as well as increasing the abundance of beneficial bacteria (such as Turicibacter, Bifidobacterium), but also improved metabolic disorders by reversing metabolite plasma levels to normality. The results of the correlation analysis demonstrated a significant association between intestinal microbiota and plasma metabolic profile, especially the strong correlation of Turicibacter and isoflavones phyto-estrogens metabolites.The combination of acupuncture and NMT could produce synergism, suggesting acupuncture-medicine combination therapy might be more conducive to the recovery of ischemic stroke. And the potential mechanism was probably related to the mediation of intestinal microecology and plasma metabolism. Turicibacter and isoflavones phyto-estrogens metabolites might be the targets for acupuncture-NMT combination for stroke. Our current findings could provide a potential therapeutic strategy against ischemic stroke.

Diabetes seriously endangers public health and brings a heavy economic burden to the country. Inflammation is one of the main inducing factors of type-2 diabetes (T2D) and may cause some complications of diabetes, such as diabetic encephalopathy and peripheral neuropathy. In-depth research and development of drugs to cure diabetes and complications are of great significance.

An adaptable and compact fast pulse sampling module was developed for the neutron–gamma discrimination. The developed module is well suited for low-cost and low-power consumption applications. It is based on the Domino Ring Sampler 4 (DRS4) chip, which offers fast sampling speeds up to 5.12 giga samples per second (GSPS) to digitize pulses from front-end detectors. The high-resolution GSPS data is useful for obtaining precise real-time neutron–gamma discrimination results directly in this module. In this study, we have implemented real-time data analysis in a field programmable gate array. Real-time data analysis involves two aspects: digital waveform integral and digital pulse shape discrimination (PSD). It can significantly reduce the system dead time and data rate processed offline. Plastic scintillators (EJ-299-33), which have proven capable of PSD, were adopted as neutron detectors in the experiments. A photomultiplier tube (PMT) (model #XP2020) was coupled to one end of a detector to collect the output light from it. The pulse output from the anode of the PMT was directly passed onto the fast sampling module. The fast pulse sampling module was operated at 1 GSPS and 2 GSPS in these experiments, and the AmBe-241 source was used to examine the neutron–gamma discrimination quality. The PSD results with different sampling rates and energy thresholds were evaluated. The figure of merit (FOM) was used to describe the neutron–gamma discrimination quality. The best FOM value of 0.91 was obtained at 2 GSPS and 1 GSPS sampling rates with an energy threshold of 1.5 MeVee (electron equivalent).

In this study, a high-time-resolution electronic module with a high channel density and low power consumption was designed for the measurement of the multi-detector array positron annihilation lifetimes. This electronic module consisted of 32 input channels, and each channel provided a high sampling rate up to 5.12 GSPS based on a Domino Ring Sampler 4 (DRS4) chip. Compared to the high-speed flash analog-digital converter (FADC), DRS4 chip has a higher channel density with an affordable lower price and power consumption. The developed electronic module was also capable of real-time data analysis for directly extracting the time information of input signals at the data acquisition site, thereby significantly decreasing the data rate. The digital constant fraction discriminator (DCFD) algorithm was implemented in the field programmable gate array (FPGA) for performing the time pick-up. The coincidence time resolution of the electronic module was measured, and the test results revealed a value of 26 ps. A prototypical 16-pixel detector module of the multi-detector system was evaluated using this electronic module, and the coincidence time resolution of the prototypical module was 411.84 ps. The electronic module was confirmed to satisfy the severe requirements of the multi-array-detector positron annihilation lifetime measurement system. It was also suitable for other high-time-resolution, high-channel-density, cost-effective, and low-power-consumption applications.

The Compton camera, which visualizes the distribution of gamma-ray sources based on the kinematics of Compton scattering, has advantage of wide field of view, broad range of energy and compact structure. In this study, we proposed a prototype of Compton camera, which included array silicon photomultiplier (SiPM)-based position-sensitive detectors, data acquisition (DAQ) system and image reconstruction system. The detectors were composed of Ce-doped Gd3Al2Ga3O12 scintillator arrays and pixel Si-PM arrays. In DAQ system, symmetric charge division circuit, impedance bridge circuit and the delay coincidence algorithm were designed to record coincidence events. Simple back-projection algorithm and list-mode maximum likelihood expectation maximization algorithm were adopted for image reconstruction. The coordinate of longitude and latitude was used for image fusion. The performance of this Compton camera prototype system was evaluated. The results indicated that this system was able to locate a 137Cs point source within 20 s with the corresponding radiation dose of ~ 1.0 μSv/h. The angular resolution of point source was ~ 7° (FWHM), and the total energy resolution of 662 keV was 7.2%. Furthermore, we succeeded in separating two point sources of different energy [22Na (511 keV), 137Cs (662 keV)] in laboratory test. This prototype of scintillator Compton camera offers capabilities for applications like source term investigation and radioactive materials detection.

Ion flow velocity measurement in the edge and scraper-off layer region is beneficial to understand the confinement related phenomenon in fusion devices such as impurity transport and plays an important role in impurity control. During the Wendelstein 7-X (W7-X) operation phase 1.2a, a multi-channel (MC) Mach probe mounted on the multi-purpose manipulator has been used to measure radial profiles of edge ion flow velocity. This MC-Mach probe consists of two polar and two radial arrays of directional Langmuir pins (28 pins in total) serving for different aims, of which the polar arrays could obtain a polar distribution of ion saturation current, while the radial arrays can be used to study the dynamic process of a radially propagated event. In this paper, we report the observation of the radially outward propagation of a low frequency mode with a speed of around 200 m/s. The first measurement of the radial ion flow velocity profile using the MC-Mach probe in the boundary plasma of the W7-X with an island divertor will also be presented.

Fast neutron detection is meaningful in many research fields such as space environment monitoring. A scintillating fiber array model for fast neutron detection was proposed and developed in 1980s. Aerospace applications of the model require electronics in small size. To design a dedicated electronic system to readout and process the 384-channel signals from scintillating fiber array, and to use the designed system to fabricate a neutron detector for aerospace applications. With the method of nuclear recoil, fast neutron is detected by tracking recoil proton of n–p scatter in scintillating plastic fibers. Using the peak-holding circuits and multiplexers, the system size and power consumption were reduced. The detector fabricated with the designed system, had 34 cm $$\times $$ 34 cm $$\times $$ 27 cm mechanical size, 20.4 kg weight, and 30.05 W power consumption. Comparing to traditional waveform sampling electronics, the designed electronics was highly integrated and had a small size. The readout electronics also gave a better energy resolution of 39% in neutron detection, while the energy resolution was 43% in previous version. In this study, a highly integrated readout electronic system was designed and verified. The detector using the system gave good performance. The designed electronics had potential development in fast neutron detection and other high energy physics detection system.

A three-dimensional position-sensitive fast neutron spectrometer is designed to measure fast neutron spectrum over 10 MeV. The detector consists of a 16 $$\times $$ 16 mutually perpendicular plastic scintillation fiber array coupled to $$2 \times 2$$ Hamamatsu H8500C position-sensitive photomultiplier tubes by optical fibers. The fiber array is fabricated with 0.5 mm $$\times $$ 3 mm fibers and 3-mm square fibers. Due to the combined application of different sizes of fibers, the detector can broaden energy dynamic range and meanwhile have good detection efficiency. The method of the combined application of different sizes of plastic fibers in the array may provide a solution to measure wider energy range of solar neutrons. In this paper, we used FLUKA to simulate the performance of the detector model and report the results of experimental studies with neutrons from a pulsed D-T neutron.

A fast neutron detection system based on a scintillating plastic fiber array and multiplexer was designed to measure the spectrum of fast neutrons ranged 10 MeV-100 MeV. With the method of nuclear recoil, the energy of incident neutron was determined by measuring the recoil proton track and deposited energy in scintillating plastic fibers. The detection system was composed of a scintillating plastic fiber array, 6 position sensitive photomultiplier tubes, and a high-density readout electronics based on the multiplexer. The scintillating plastic fiber array was made as a staggered structure with two kinds of fibers in different sizes (0.5 mm-square fiber and 3 mm-square fiber). The structure provided a wider detection energy range and better detection efficiency than arrays made with uniform plastic fibers. A dedicated digital electronics system was well designed to control the whole readout system to provide 384-channel signal processing. The detector had a 48 mm × 48 mm effective detection area and a mechanical size of 34 cm × 34 cm × 27 cm. In the simulation of the detector model performance, the system gave an energy resolution of 23%-35% for neutrons ranged 10 MeV-100 MeV. Experimental results showed that the detector had a good energy linearity and energy resolutions were, respectively, 35.82% at 14.817 MeV, 36.84% at 21.264 MeV, 35.90% at 23.069 MeV, and 32.90% at 24.220 MeV. The optimized prototype model had potential in increasing fast neutron detection performance.

A novel non-linear phenomenon, namely simultaneous electrochemical oscillations both on the cathode with Fe(CN) 6 3− reduction and on the anode with Fe(CN) 6 4− oxidation, is described. Complicated quasi-periodic behavior occurred in the simultaneous potential oscillations by the coupling of the simple period-one oscillations with two incommensurate oscillating frequencies, and complex periodic behavior appeared in the simultaneous current oscillations with the frequency locking.

Geometrical effects on the oscillatory behavior during the reduction of iodate in an alkaline solution have been studied in detail. We have found that the geometrical factors greatly affect the oscillatory behavior when the iodate concentration is smaller, and chaos appears on the electrodes with smaller size or smoother surface, whereas at higher iodate concentration, the influence from the geometrical factors is minor and periodic behavior occurs instead, though some differences still exist in the waveforms with different roughness. The geometrical factors affect mainly the convection mass transfer of the iodate induced by the hydrogen evolution, in addition to the different adsorption.

We have discovered a new kind of current oscillation during the reduction or oxidation of some anions, which appeared over the limiting reduction or oxidation current of the anions and was loaded on the current of hydrogen or oxygen evolution. The overlap of a positive feedback (convection mass transfer of the anions induced by hydrogen or oxygen evolution, and the increase of the potential difference in the cell when the current is smaller) and a negative feedback (depletion of the surface concentration of the anions by reduction or oxidation, and the decrease of the potential difference in the cell when the current is larger) between the bistable states accounts for the oscillations, and a ‘hidden’ negative impedance in the second ascending branch of the polarization curve was observed for the first time. Our model has also shed some light on the other systems reported in the literature, in which convection mass transfer also plays an important role in the current oscillations. In addition, the potential oscillations during the oxidation of Fe(CN) 6 4− are reported here for the first time, and are similar to the potential oscillations during the reduction of Fe(CN) 6 3− reported in our previous paper [Z. Li, J. Cai, S. Zhou, J. Electroanal. Chem., in press].

Potential oscillations, which were observed during Fe(CN)63− reduction under galvanostatic conditions in 1 mol dm−3 NaOH solution on a platinum electrode, are described. The bifurcation boundaries were measured in the parameter plane of applied current vs. Fe(CN)63− concentration. A broad limiting current plateau (zero slope) occurring in the current-potential curve in combination with a negative real impedance is a typical characteristics for this kind of oscillation, and the oscillation amplitudes are within that region. The bistability, i.e., Fe(CN)63− reduction and hydrogen evolution at different potentials, coupled with convection feedback induced by hydrogen evolution, accounts for the oscillations. The sequence of chaotic-quasiperiodic-periodic-quasiperiodic oscillations, which appeared when the applied current was increased monotonously, was characterized by time series, power spectra, phase portraits and one-dimensional maps.

Potential oscillations during the reduction of iodate ions in alkaline solution under galvanostatic conditions have been re-investigated without adding iodide. The oscillations can take place only when the applied current is larger than the limiting current, and the oscillation amplitudes are within the plateau region of the limiting current. The bistability, i.e., iodate reduction and hydrogen evolution at different potentials, coupled with convection feedback, induced by hydrogen evolution, accounts for the oscillations. The mechanism was supported by the experimental results of current sweep and cyclic voltammetry. Our study shows that physical processes, i.e., alternately predominant mass transfer of the iodate by diffusion and by convection, play an important role in the oscillations.

A new multi-channel poloidal correlation reflectometry is developed at Experimental Advanced Superconducting Tokamak. Eight dielectric resonator oscillators with frequencies of 12.5 GHz, 13.5 GHz, 14.5 GHz, 15 GHz, 15.5 GHz, 16 GHz, 17 GHz, and 18 GHz are used as sources. Signals from the sources are up-converted to V band using active quadruplers and then coupled together. The output waves are launched by one single antenna after passing through a 20 dB directional coupler which can provide the reference signal. Two poloidally separated antennae are installed to receive the reflected waves from plasma. The reference and reflected signals are down-converted by mixing with a quadrupled signal from a phase-locked source with a frequency of 14.2 GHz and the IF signals pass through the filter bank. The resulting signals from the mixers are detected by I/Q demodulators. The setup enables the measurement of density fluctuation at 8 (radial) × 2 (poloidal) spatial points. A coherent mode with an increasing velocity from 50 kHz to 100 kHz is observed by using the system. The mode is located in the steep gradient region of the pedestal.

A new model for the anomalous codeposition of alloys is based on the kinetic characteristics of metal electrodeposition and the effect of hydrogen evolution accompanying the deposition. The less noble metal has intrinsically faster kinetics and so its deposition rate can be controlled mainly by diffusion mass transfer in a certain range of overpotentials; the convection induced by hydrogen evolution can speed up the relative deposition rate of this less noble metal when it is mainly diffusion-influenced. In contrast with previous models, such as the hydroxide suppression hypothesis, the mononyaroxiae-discharge-controlled mechanism, and the competitive adsorption effect, our model can explain naturally and completely anomalous codeposition, i.e. the preferential deposition of the less-noble metal, a problem in alloy electrodeposition that has persisted for a century.

Unlike in alkaline solutions, totally different oscillatory behavior has been observed during the reduction of IO3− in an acidic solution, and the addition of some organic substances in the alkaline solution varies the current range where the potential oscillations occur to remarkably different extent, depending on the electric charge, length of chain, and concentration of the additive. Some explanation is given for these new observations.

A bi-directional multi-channel retarding field analyzer (RFA) probe has been successfully developed for the first time on the Wendelstein 7-X (W7-X) stellarator boundary plasma. Modifications to the RFA prototype hardware and its upgrade for the two W7-X island divertor campaigns are presented, including the electronics. In this paper the experiences and challenges operation and customizing an RFA at W7-X are discussed, as well as the data analysis using a maximum coefficient of determination method to obtain the ion temperature based on the measured modulated ion current. Edge ion temperature profiles have been measured in the standard and high iota configurations. Previous article in issue