Fabrication of high-concentration Cu-doped deuterated targets for fast ignition experiments

In high-energy-density physics, including inertial fusion energy using high-power lasers, doping tracer atoms and deuteration of target materials play an important role in diagnosis. For example, a low-concentration Cu dopant acts as an x-ray source for electron temperature detection while a deuterium dopant acts as a neutron source for fusion reaction detection. However, the simultaneous achievement of Cu doping, a deuterated polymer, mechanical toughness and chemical robustness during the fabrication process is not so simple. In this study, we report the successful fabrication of a Cu-doped deuterated target. The obtained samples were characterized by inductively coupled plasma optical emission spectrometry, differential scanning calorimetry and Fourier transform infrared spectroscopy. Simultaneous measurements of Cu K-shell x-ray emission and beam fusion neutrons were demonstrated using a petawatt laser at Osaka University.Ikeda T., Kaneyasu Y., Hosokawa H., et al. Fabrication of high-concentration Cu-doped deuterated targets for fast ignition experiments. Nuclear Fusion 63, 016010 (2023); https://doi.org/10.1088/1741-4326/aca2ba

Demonstration of a spherical plasma mirror for the counter-propagating kilojoule-class petawatt LFEX laser system

A counter-propagating laser-beam platform using a spherical plasma mirror was developed for the kilojoule-class petawatt LFEX laser. The temporal and spatial overlaps of the incoming and redirected beams were measured with an optical interferometer and an x-ray pinhole camera. The plasma mirror performance was evaluated by measuring fast electrons, ions, and neutrons generated in the counter-propagating laser interaction with a Cu-doped deuterated film on both sides. The reflectivity and peak intensity were estimated as ∼50% and ∼5 × 1018 W/cm2, respectively. The platform could enable studies of counter-streaming charged particles in high-energy-density plasmas for fundamental and inertial confinement fusion research.Kojima S., Abe Y., Miura E., et al. Demonstration of a spherical plasma mirror for the counter-propagating kilojoule-class petawatt LFEX laser system. Optics Express 30, 43491 (2022); https://doi.org/10.1364/oe.475945

Fabrication of high-concentration Cu-doped deuterated targets for fast ignition experiments

先端科学・社会共創推進機構In high-energy-density physics, including inertial fusion energy using high-power lasers, doping tracer atoms and deuteration of target materials play an important role in diagnosis. For example, a low-concentration Cu dopant acts as an x-ray source for electron temperature detection while a deuterium dopant acts as a neutron source for fusion reaction detection. However, the simultaneous achievement of Cu doping, a deuterated polymer, mechanical toughness and chemical robustness during the fabrication process is not so simple. In this study, we report the successful fabrication of a Cu-doped deuterated target. The obtained samples were characterized by inductively coupled plasma optical emission spectrometry, differential scanning calorimetry and Fourier transform infrared spectroscopy. Simultaneous measurements of Cu K-shell x-ray emission and beam fusion neutrons were demonstrated using a petawatt laser at Osaka University

Analytical and experimental studies of dragging hall anchors through rock berm

An analytical method is proposed in this paper to calculate the maximum embedded depth of a dragged Hall anchor when passing through rock berm and to thus define a minimum buried depth of pipelines in rock berm to prevent pipelines from being damaged by dragging anchors. The movement of a Hall anchor in rock berm is interpreted based on the equilibrium conditions for resisting and driving moments acting on the anchor. To verify the accuracy of the proposed analytical method, model tests were carried out by using three scaled Hall anchor models and dragging them through rock berm. The comparisons between the two studies show that the average value of their differences for the stable embedded depth of a Hall anchor in sand and in rock berm are only 1.7% and 2.7%, respectively. The good agreements indicate that the proposed method is accurate enough to calculate the minimum buried depth of pipeline in rock berm during pipeline design.Accepted versio

Size-Fractionated Filtration Combined with Molecular Methods Reveals the Size and Diversity of Picophytoplankton

In this study, flow cytometry (FCM) and size-fractionated filtration, together with high-throughput molecular sequencing methods (SM), were used to investigate picophytoplankton. A particle separation filter and a higher-throughput sequencing method were used to evaluate the composition of a euphotic zone of picophytoplankton—especially picoeukaryotic phytoplankton—in the Western Pacific, and the results of flow cytometry, which is a classic way to detect picophytoplankton, were used as a standard to evaluate the reliability of the results of the SMs. Within a water column of 200 m, six water depths (5, 25, 50, 113 (DCM), 150, and 200 m) were established. In order to further study the particle size spectra of the picophytoplankton, size-fractionated filtration was used to separate water samples from each water depth into three particle size ranges: 0.2–0.6, 0.6–1.2, and 1.2–2 μm. A total of 36 (6 × 3 × 2) samples were obtained through PCR amplification of the 18S rRNA V4 hypervariable region and 16S rRNA, which were biased toward phytoplankton plastids, and then high-throughput sequencing was performed. The estimation of the picophytoplankton diameter relied on forward scattering (FSC) through FCM. The estimation of the vertical distribution and diameter of the picophytoplankton using the SM was consistent with the results with FCM; thus, we believe that the estimation of picophytoplankton composition with the SM has value as a reference, although the size-fractionated filtration seemed to cause some deviations. In addition to Prochlorococcus and Synechococcus, the SM was used to evaluate the composition of picoeukaryotic phytoplankton, which mainly included Prymnesiophycea (Haptophyta) (38.15%), Cryptophyceae (Cryptophyta) (22.36%), Dictyochophyceae (Chrysophyta) (12.22%), and Mamiellophyceae (Chlorophyta) (3.31%). In addition, the SM also detected Dinophyceae (Dinoflagellata) (11.69%) sequences and a small number of Bacillariophyceae (Diatom) (1.64%) sequences, which are generally considered to have large particle sizes. The results of the SM also showed that the picoeukaryotic phytoplankton were not evenly distributed in the euphotic layer, and the vertical distributions of the different picoeukaryotic phytoplankton were different. An analysis of correlations with environmental factors showed that temperature was the main environmental factor controlling the vertical distribution of picophytoplankton

Analytical solutions for geosynthetic tube resting on rigid foundation

Geosynthetic tubes inflated with water, clay slurry or sand have been widely used for large dike construction in land reclamation projects. In this paper, analytical solutions for geosynthetic tube resting on rigid foundation is presented by adopting an approach similar to that presented by Leshchinsky et al. (1996). The proposed method allows a quick preliminary design to be made for using a closed-form solution. To simplify the analysis, relationships between geometrical parameters and pumping pressure are established using numerical method. The analytical solutions were compared with several existing solutions and good agreements were achieved.Published versio

A simplified method for design of geosynthetic tubes

A simplified method for the design of impermeable geosynthetic tubes inflated using liquid is proposed in this paper. Adopting a computer program for an existing theoretical model, relationships between pumping pressure and geometric parameters for geosynthetic tubes can be established. A set of simplified dimensionless design equations are then derived using the Chapman–Richard curve fitting method. The validity of this simplified method was verified using other established methods and laboratory model tests. The proposed simplified method can thus be used for routine or preliminary design.Accepted versio

Modified duct-to-mucosa versus conventional pancreaticoenterostomy for pancreaticoduodenectomy: a retrospective cohort study based on propensity score matching analysis

Abstract Background Clinically relevant postoperative pancreatic fistula (CR-POPF) remains the most common neopathy after pancreatoduodenectomy (PD). An ideal pancreaticoenterostomy (PE) which can effectively reduce the incidence of CR-POPF and its potential neopathy is needed. We aimed to assess the efficacy of our modified duct-to-mucosa PE in the PD. Method From January 2011 to December 2017, 233 consecutive patients with PD were retrospectively included from Shenzhen People’s Hospital. After propensity score matching (PSM), there were 82 patients in both the modified duct-to-mucosa PE group (group A) and the conventional end-to-side inserting PE group (group B), respectively. The clinical course and the incidence of postoperative neopathy were compared between groups. Logistic regression method was utilized to analyze the association between PE approach and CR-POPF. Results The PE time was shorter in group A (9.3 ± 1.8 min vs. 21.5 ± 2.8 min, P  II) [7.3% (5/82) vs. 17.1% (14/82), P = 0.028] and incidence of CR-POPF [1.2% (1/82) vs. 19.5% (12/82), P < 0.001] than the group B. Our modified duct-to-mucosa PE technique was associated with a reduced risk for CR-POPF (OR, 0.11 [95% CI, 0.02–0.57]; P = 0.009) as compared with the conventional end-to-side inserting PE. Conclusion Compared with conventional end-to-side inserting PE, our modified duct-to-mucosa PE technique can effectively reduce the incidences of postoperative neopathy and CR-POPF. Trial registration Researchregistry3877. Registered 24 March 2018. Retrospectively registered

Prevalence and Risk Factors of Reduced Bone Mineral Density in Systemic Lupus Erythematosus Patients: A Meta-Analysis

Background. We aimed to conduct a meta-analysis concerning the frequency and risk factors of reduced bone mineral density (BMD) in systemic lupus erythematosus (SLE) with evidence from published studies. Methods. A comprehensive literature search was conducted based on the EMBASE, Web of Science, PubMed, and Cochrane Library databases up to March 5th, 2017. Eligible studies reported any prevalence of reduced BMD in SLE patients. All risk factors with odds ratios or risk ratios associated with reduced BMD were extracted. Results. 71 reports with 33527 SLE patients were included. Low BMD, osteopenia, and osteoporosis at any site were presented, respectively, in 45%, 38%, and 13% of the SLE patients. The prevalence of osteoporosis increased with the advancing of age, while U-shaped associations between age and the prevalence of low BMD and osteopenia were found. Lumbar spine was indicated to have higher prevalence of osteoporosis. Age, disease duration, drugs use, and many other factors were identified as predictors of reduced BMD. Conclusion. Low BMD, osteoporosis, and osteopenia appeared to be prevalent in patients with SLE. Risk factors of reduced BMD were various

A pilot test on a membraneless vacuum preloading method

A membraneless vacuum preloading method is proposed in this paper for soft soil improvement. The method offers several advantages over the conventional vacuum preloading in which membrane is used to create the airtight condition and sand blanket layer to distribute vacuum. To assess the effectiveness of the proposed method, a pilot test was conducted at a land reclamation site in Tianjin, China. The ground settlement and the pore water pressure (PWP) at different elevations in soil were measured. After vacuum preloading, the average water content of the soft soils reduced by approximately 12% and the undrained shear strength increased twofold. The average degree of consolidation at the end of the vacuum preloading achieved 85.1% based on the settlement data and 84.5% based on the PWP data. The pilot test data have shown that the proposed method exhibits similar efficiencies to the conventional vacuum preloading method.Accepted versio