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Laser pulses of 200 ps with extremely high intensities and high energies are sufficient to satisfy the demand of shock ignition, which is an alternative path to ignition in inertial confinement fusion (ICF). This paper reports a type of Brillouin scheme to obtain high-intensity 200-ps laser pulses, where the pulse durations are a challenge for conventional pulsed laser amplification systems. In the amplification process, excited Brillouin acoustic waves fulfill the nonlinear optical effect through which the high energy of a long pump pulse is entirely transferred to a 200-ps laser pulse. This method was introduced and achieved within the SG-III prototype system in China. Compared favorably with the intensity of
in existing ICF laser drivers, a 6.96-
pulse with a width of 170 ps was obtained in our experiment. The practical scalability of the results to larger ICF laser drivers is discussed.
The North Pacific Ocean (NPO) has received abundant aeolian dust transported by westerlies from the Asian inland. The aeolian components preserved in NPO sediments record information on palaeoclimatic and palaeoenvironmental changes in Asian source areas at different timescales. Previous studies have systematically investigated the source–sink effect of aeolian dust using the sedimentology, geochemistry, isotope and magnetic methods. In this study, we focus more on recent developments of aeolian signals in NPO sediments obtained by magnetic approaches. Generally, aeolian components contain a mixture of magnetite, maghemite, hematite and goethite of different origins. Magnetic properties (mineral category, concentration and particle size) of these minerals are modulated primarily by climatic/environmental conditions in source areas and sorting effects during the transportation process. Compared with the other methods, magnetic measurements have the advantages of non-sample destruction, high sensitivity and high efficiency. Finally, future studies are also discussed to address the importance of magnetism for tracing the dynamic transportation processes of the aeolian dust.
This study aim to derive and validate a simple and well-performing risk calculator (RC) for predicting psychosis in individual patients at clinical high risk (CHR).
From the ongoing ShangHai-At-Risk-for-Psychosis (SHARP) program, 417 CHR cases were identified based on the Structured Interview for Prodromal Symptoms (SIPS), of whom 349 had at least 1-year follow-up assessment. Of these 349 cases, 83 converted to psychosis. Logistic regression was used to build a multivariate model to predict conversion. The area under the receiver operating characteristic (ROC) curve (AUC) was used to test the effectiveness of the SIPS-RC. Second, an independent sample of 100 CHR subjects was recruited based on an identical baseline and follow-up procedures to validate the performance of the SIPS-RC.
Four predictors (each based on a subset of SIPS-based items) were used to construct the SIPS-RC: (1) functional decline; (2) positive symptoms (unusual thoughts, suspiciousness); (3) negative symptoms (social anhedonia, expression of emotion, ideational richness); and (4) general symptoms (dysphoric mood). The SIPS-RC showed moderate discrimination of subsequent transition to psychosis with an AUC of 0.744 (p < 0.001). A risk estimate of 25% or higher had around 75% accuracy for predicting psychosis. The personalized risk generated by the SIPS-RC provided a solid estimate of conversion outcomes in the independent validation sample, with an AUC of 0.804 [95% confidence interval (CI) 0.662–0.951].
The SIPS-RC, which is simple and easy to use, can perform in the same manner as the NAPLS-2 RC in the Chinese clinical population. Such a tool may be used by clinicians to counsel appropriately their patients about clinical monitor v. potential treatment options.
To improve detection performance of passive location system based on troposcatter, we propose a blind signal detection algorithm. According to our algorithm, complementary ensemble empirical mode decomposition decomposes the received signal into several intrinsic mode functions (IMFs). To reconstruct the signal and background noises, difference between the entropy of adjacent IMFs is utilized as a standard. Different IMFs are utilized to estimate threshold of energy detection algorithm and energy level of received signal. Simulation examples indicate that the proposed algorithm can blindly and effectively detect the signal.
To eliminate the toxic effect of chemotherapy drug of lobaplatin (LBP) on body tissue in liver cancer therapy, this work prepared a nanodrug carrier based on polyethylene glycol-modified carbon nanotubes (PEG–CNTs) and then constructed a targeted drug delivery system (LBP–PEG–CNTs) by loading LBP on PEG–CNTs. Fluorescein isothiocyanate (FITC) was used to label PEG–CNTs to observe the cellular uptake of PEG–CNTs. In addition, the inhibitions of LBP–PEG–CNTs on HepG2 cells were investigated. The results show that the FITC-labeled PEG–CNTs have good cell penetrability; meanwhile, LBP–PEG–CNTs have good stability, pH-controlled release property, and high inhibition rate on HepG2 cells. To be specific, 80% of LBP is released under physiological conditions of liver cancer cells at pH 5.0, and LBP–PEG–CNTs show a high inhibition rate of 77.86% on HepG2 cells, demonstrating that they have targeted, pH-controlled release and inhibition properties on HepG2 cells.
Monosized spherical Cu–20% Sn (wt%) alloy particles with diameter ranging from 70.6 to 334.0 μm were prepared by the pulsated orifice ejection method (termed “POEM”). Fully dense without pores and bulk inclusions, the cross-sectional micrographs of the spherical alloy particles indicate an even distribution of Cu and Sn. These spherical Cu–Sn alloy particles exhibit a good spherical shape and a narrow size distribution, suggesting that the liquid Cu–Sn alloy can completely break the balance between the surface tension and the liquid static pressure in the crucible micropores and accurately control the volume of the droplets. Furthermore, the cooling rate of spherical Cu–20% Sn alloy particles is estimated by a Newton’s cooling model. The cooling rate of the Cu–20% Sn alloy particle decreases gradually with the particle diameter increasing. Smaller particles have higher cooling rates and when the particle diameter is less than 70 μm, the cooling rate of particles can reach more than 3.3 × 104 K/s. The secondary dendrite arm spacing has strong dependence on particle diameter which increases gradually with the increase of particle diameter. The results demonstrate that POEM is an effective route for fabrication of high-quality monosized Cu–20% Sn alloy particles.
Herein we describe the use of a new DNAzyme/graphene hybrid material as a biointerfaced sensing platform for optical detection of pathogenic bacteria. The hybrid consists of a colloidal graphene nanomaterial and an Escherichia coli-activated RNA-cleaving DNAzyme and is prepared via non-covalent self-assembly of the DNAzyme onto the graphene surface. Exposure of the hybrid material to E. coli-containing samples results in the release of the DNAzyme, followed by the cleavage-mediated production of a fluorescent signal. Given that specific RNA-cleaving DNAzymes can be created for diverse bacterial pathogens, direct interfacing of graphene materials with such DNAzymes represents a general and attractive approach for real-time, sensitive, and highly selective detection of pathogenic bacteria.
In high power laser facility for inertial confinement fusion research, final optics assembly (FOA) plays a critical role in the frequency conversion, beam focusing, color separation, beam sampling and debris shielding. The design and performance of FOA in SG-II Upgrade laser facility are mainly introduced here. Due to the limited space and short focal length, a coaxial aspheric wedged focus lens is designed and applied in the FOA configuration. Then the ghost image analysis, the focus characteristic analysis, the B integral control design and the optomechanical design are carried out in the FOA design phase. In order to ensure the FOA performance, two key technologies are developed including measurement and adjustment technique of the wedged focus lens and the stray light management technique based on ground glass. Experimental results show that the design specifications including laser fluence, frequency conversion efficiency and perforation efficiency of the focus spot have been achieved, which meet the requirements of physical experiments well.
In this paper, zircon U–Pb geochronology, major and trace elements, and Sr–Nd isotope geochemistry of the Baiyanghe dolerites in northern West Junggar of NW China are presented. The U–Pb dating of zircons from the dolerites yielded ages of 272.2±4 Ma and 276.7±6.2 Ma, which indicate the emplacement times. The dolerites are characterized by minor variations in SiO2 (46.89 to 49.07 wt%), high contents of Al2O3 (13.60 to 13.92 wt%) and total Fe2O3 (11.14 to 11.70 wt%), and low contents of MgO (2.67 to 3.64 wt%) and total alkalis (Na2O+K2O, 5.1 to 5.97 wt%, K2O/Na2O = 0.37–0.94), which indicate affinities to metaluminous tholeiite basalt. The REE pattern ((La/Sm)N = 2.25–2.34, (La/Yb)N = 7.42–8.36), V–Ti/1000 and 50*Zr–Ti/50–Sm discrimination diagrams show that these rocks are OIB-type. The high contents of Zr and Ti indicate a within-plate tectonic setting, and samples plot in the ‘plume source’ field shown on the Dy/Yb(N) versus Ce/Yb(N) diagram. The positive εNd(t) values (+7.09 to +7.48), high initial 87Sr/86Sr ratios (0.70442 to 0.70682) and depletions of Nb and Ta elements in the samples can be explained by the involvement of subducted sediments. In summary, it is possible that the Baiyanghe dolerites were derived from an OIB-like mantle source and associated with a mantle plume tectonic setting. Therefore, our samples provide the youngest evidence for the existence of a mantle plume, which may provide new insights into the Late Palaeozoic tectonic setting of West Junggar.
The Shen-Guang II Upgrade (SG-II-U) laser facility consists of eight high-power nanosecond laser beams and one short-pulse picosecond petawatt laser. It is designed for the study of inertial confinement fusion (ICF), especially for conducting fast ignition (FI) research in China and other basic science experiments. To perform FI successfully with hohlraum targets containing a golden cone, the long-pulse beam and cylindrical hohlraum as well as the short-pulse beam and cone target alignment must satisfy tight specifications (30 and
rms for each case). To explore new ICF ignition targets with six laser entrance holes (LEHs), a rotation sensor was adapted to meet the requirements of a three-dimensional target and correct beam alignment. In this paper, the strategy for aligning the nanosecond beam based on target alignment sensor (TAS) is introduced and improved to meet requirements of the picosecond lasers and the new six LEHs hohlraum targets in the SG-II-U facility. The expected performance of the alignment system is presented, and the alignment error is also discussed.
Auto-alignment is a basic technique for high-power laser systems. Special techniques have been developed for laser systems because of their differing structures. This paper describes a new sensor for auto-alignment in a laser system, which can also serve as a reference in certain applications. The authors prove that all of the beam transfer information (position and pointing) can theoretically be monitored and recorded by the sensor. Furthermore, auto-alignment with a single lens sensor is demonstrated on a simple beam line, and the results indicate that effective auto-alignment is achieved.
We report a new pulsed chemical vapor deposition (PCVD) process to deposit nickel (Ni) and nickel carbide (Ni3Cx) thin films, using bis(1,4-di-tert-butyl-1,3-diazabutadienyl)nickel(II) precursor and either H2 gas or H2 plasma as the coreactant, at a temperature from 140 to 250 °C. All the PCVD films are fairly pure with low levels of N and O impurities. The films deposited with H2 gas at ≤200 °C are faced centered cubic-phase Ni metal films with low C content; but at ≥220 °C, another phase of rhombohedral Ni3C is formed and the C content increases. However, when H2 plasma is used, the films are always in rhombohedral Ni3C phase for the entire temperature range.
In the past few years, our group worked on the area of transformation from the two-dimensional (2-D) nanocrystalline films to one-dimensional (1-D) nanomaterials by using thermal oxidation. In this paper, we overview the research work on the controllable growth processes, transformation phenomena, growth mechanisms and applications. In general, the preparation process includes the following steps: 1) prepare a pure metal nanocrystalline film via a pulse electro – deposition; 2) grow variant 1-D nanomaterials, such as carbon nanotubes (CNTs), carbon nanofibers (CNFs), and 1-D metal oxide nanoneedles involving ZnO, CuO and Fe3O4, etc. by using this film as catalyst. This process exhibits the following features: 1) the 1-D nanomaterials grow according to “base growth” model and no residual catalyst exists at the tip of the products; 2) the diameter of the 1-D nanomaterials can be controlled by controlling grain sizes of the 2-D films through adjusting pulse electro-deposition parameters; 3) it is more easily to get the 1-D nanomaterials with large area, uniform, vertical alignment and good shape on the substrates. We propose a “solid state based-up diffusion growth mechanism” for growth of the 1-D metal oxide nanoneedles, and “base growth model” for the 1-D carbon nanomaterials. The physical properties, such as Field emission and magnetics, of the 1-D metal oxide nanoneedles were studied, which showed desired values. In addition, we couple the ZnO nanoneedles with NiO, TiO2, graphene, Au nanoparticles, etc. for enhancing photocatalytic properties in the areas of environmental purification.
This study examined the mediating effects of future social expectations and interpersonal distrust on the relationship between individual relative deprivation and intention to rebel. Data were gathered from 807 people from multiple occupational backgrounds in a municipality in southwest China. Structural equation modelling showed that individual relative deprivation predicted intention to rebel directly and also that it predicted intention to rebel indirectly via negative future social expectations, interpersonal distrust, and a chain mediating effect of negative future social expectations and interpersonal distrust. These results highlight the importance of the associations between future social expectations and interpersonal distrust with intention to rebel in people who report relative deprivation. The findings also indicate that prevention and intervention programs related to relative deprivation and intention to rebel in China are worthy of further research.
Terrestrial plant remains in the sediments of lakes from semi-arid and arid regions are rare and therefore the establishment of a sediment chronology depends on accurate assessment of the reservoir effect of the lake water. In a study of Genggahai Lake in the Gonghe Basin, northeastern Qinghai-Tibetan Plateau, we used accelerator mass spectrometry radiocarbon (AMS 14C) dating to determine the age of (1) dissolved inorganic carbon in the water (DICLW), (2) macrophyte remains in the uppermost samples of core sediments, (3) living P. pectinatus in the lake, and (4) dissolved inorganic carbon of spring water in the catchment. The results show that the ages of the DICLW (910 14C yr BP on average) were much younger than the ages of the groundwater (6330 14C yr BP on average), which may result mainly from CO2 exchange between the lake water and the atmosphere. In addition, the 14C ages of DICLW and macrophyte remains in the uppermost core sediments varied from site to site within the lake, which we ascribe to the different photosynthesis rates of Chara spp. and vascular plants. The higher photosynthesis rate of Chara spp. decreases lake-water pCO2, which leads to more atmospheric CO2 being absorbed by the lake water, and thereby greatly reducing the age of carbon species in areas dominated by Chara spp. Although Genggahai Lake is well mixed, the differences between the apparent ages of the lake water are significantly modulated by the photosynthesis intensity of submerged plants.
In recent years, hand, foot, and mouth disease (HFMD) has been increasingly recognized as a critical challenge to disease control and prevention in China. Previous studies have found that meteorological factors such as mean temperature and relative humidity were associated with HFMD. However, little is known about whether the diurnal temperature range (DTR) has any impact on HFMD. This study aimed to quantify the impact of DTR on childhood HFMD in 18 cities in Sichuan Province. A distributed lag non-linear model was adopted to explore the temporal lagged association of daily temperature with age-, gender- and pathogen-specific HFMD. A total of 290 123 HFMD cases aged 0–14 years were reported in the 18 cities in Sichuan Province. The DTR–HFMD relationships were non-linear in all subgroups. Children aged 6–14 years and male children were more vulnerable to the temperature changes. Large DTR had the higher risk estimates of HFMD incidence in cases of EV71 infection, while small DTR had the higher risk estimates of HFMD incidence in cases of CV-A16 infection. Our study suggested that DTR played an important role in the transmission of HFMD with non-linear and delayed effects.
Pre-Quaternary terrestrial climate variability is less well understood than that during the Quaternary. The continuous eolian Red Clay sequence underlying the well-known Quaternary loess-paleosol sequence on the Chinese Loess Plateau (CLP) provides an opportunity to study pre-Quaternary terrestrial climate variability in East Asia. Here, we present new mineral magnetic records for a recently found Red Clay succession from Shilou area on the eastern CLP, and demonstrate a marked East Asian climate shift across the Miocene-Pliocene boundary (MPB). Pedogenic fine-grained magnetite populations, ranging from superparamagnetic (SP)/single domain (SD) up to small pseudo-single domain (PSD) sizes (i.e., from <30 nm up to ~1000 nm), dominate the magnetic properties. Importantly, our mineral magnetic results indicate that both pedogenic formation of SP grains and transformation of SP grains to SD and small PSD grains accelerated across the MPB in the Shilou Red Clay, which are indicative of enhanced pedogenesis. We relate this enhanced pedogenesis to increased soil moisture availability on the CLP, associated with stronger Asian Summer Monsoon precipitation during an overall period of global cooling. Our study thus provides new insights into the Miocene-Pliocene climate transition in East Asia.
Activated carbon (AC) has been widely used as catalyst for oxygen reduction reaction (ORR) in air-cathode microbial fuel cells (MFCs). Here we demonstrate a new method to improve the AC air-cathode by blending it with reduced graphene oxide (rGO). rGO sheets are first deposited on Ni foam and AC is then brushed onto it with controlled mass loading. rGO sheets not only improve the electrical conductivity of AC, but also provide a large number of ORR areas. Rotating ring disk electrode measurements reveal that the number of transferred electrons at rGO-AC cathode is 3.5, indicating the four-electron pathway is the dominant process. Significantly, the MFC with rGO-AC cathode delivers a maximum power density of 2.25 ± 0.05 W/m2, which is substantially higher than that of plain AC cathode (1.35 ± 0.07 W/m2) and those for other air-cathode MFCs using AC as ORR catalyst under the same mass loading.