Temperature-insensitive reading of a flash memory cell

The temperature characteristics of the read current of the NOR embedded flash memory with a 1.5T-per-cell structure are theoretically analyzed and experimentally verified.We verify that for a cell programmed with a“10”state,the read current is either increasing,decreasing,or invariable with the temperature,essentially depending on the reading overdrive voltage of the selected bitcell,or its programming strength.By precisely controlling the programming strength and thus manipulating its temperature coefficient,we propose a new setting method for the reference cells that programs each of reference cells to a charge state with a temperature coefficient closely tracking tail data cells,thereby solving the current coefficient mismatch and improving the read window.

Geochemical characteristics of platinum-group elements in polymetallic nodules from the Northwest Pacific Ocean

Polymetallic nodules and cobalt (Co)-rich crusts are enriched in platinum-group elements (PGEs),especially platinum (Pt) and may be important sinks of PGEs.At present,little information is available on PGEs in polymetallic nodules,and their geochemical characteristics and the causes of PGEs enrichment are unclear.Here PGEs of polymetallic nodules from abyssal basin in the Marcus-Wake Seamount area of the Northwest Pacific Ocean are reported and compared with the published PGEs data of polymetallic nodules and Co-rich crusts in the Pacific.The total PGEs (ΣPGE) content of polymetallic nodules in study area is 258×10^–9) in average,markedly higher than that of Clarion-Clipperton Zone (CCZ) nodules (ΣPGE=127×10^–9) and lower than that of Co-rich crusts in the Marcus-Wake Seamount (ΣPGE=653×10^–9),similar to that of Co-rich crusts in the South China Sea(ΣPGE=252×10^~–9).The CI chondrite-normalized PGEs patterns in different regions of polymetallic nodules and cobalt-rich crusts are highly consistent,with all being characterized by positive Pt and negative Pd anomalies These results,together with those of previous studies,indicate that PGEs in polymetallic nodules and Co-rich crusts are mainly derived directly from seawater.Pt contents of polymetallic nodules from the study area are negatively correlated with water depth,and Pt/ΣPGE ratios in nodules there are also lower than those of the Corich crusts in the adjacent area,indicating that sedimentary water depth and oxygen fugacity of ambient seawater are the possible important controlling factors for Pt accumulation in crusts and nodules.

Corrigendum to“First demonstration of improving laser propagation inside the spherical hohlraums by using the cylindrical laser entrance hole”[Matter Radiation Extremes 1(1)(2016)2-7]

Corrigendum Text:On page 2 of this letter,there is a misprint in the unit.The unit of the geometrical dimension of the spherical hohlraums on this page should always be“mm”rather than“mm”,i.e.in the second paragraph,“…with 800 J per beam at 0.35 mm…”should be“…with 800 J per beam at 0.35 mm…”,“The slit of 400 mm width is parallel…”should be“The slit of 400 mm width is parallel…”,“The laser focal diameter is about 500 mm…”should be“The laser focal diameter is about 500 mm…”;in the third paragraph,“…we take 850 mm as the radius…”should be“…we take 850 mm as the radius…”,“The LEH radius R_(L) is 400 mm…”should be“The LEH radius R_(L) is 400 mm…”,“…the radius of the cylindrical LEH outer ring is taken as 1.5 R_(L)=600 mm”should be“…the radius of the cylindrical LEH outer ring is taken as 1.5 R_(L)=600 mm”.This mistake does not affect any of the main results of the original letter.

Evolution and diagenetic implications of framboids in the methane-related carbonates of the northern Okinawa Trough

Authigenic carbonate samples were collected from the northern Okinawa Trough.Based on their carbon and oxygen isotopes,these samples were found to be methane-related carbonates precipitated by the anaerobic oxidation of methane(AOM).Petrological analysis revealed numerous framboidal pyrites that had been partly oxidized.In order to trace the variation and diagenetic information of these framboidal pyrites,their diameters and geochemical components were studied using an electron probe.The results showed that their diameters varied from 4μm to 17μm(n=60;geometric mean of 9.9μm)and were of a normal distribution.The diameters of single pyrite that formed the framboidal pyrites varied from 1μm to 2μm.The framboidal pyrites with diameters of 6–14μm accounted for~80%of the total.The geometric mean of 9.9μm indicates that they are probably diagenetic pyrites that were precipitated in a lower dysoxic environment(weakly oxygenated bottom waters).The S/Fe ratio of the framboidal minerals ranged from 0 to 1.67,and the pyrite content of single framboid varied between 0%and 86.4%.Therefore,numerous pyrites were oxygenated to iron oxides or oxyhydroxides,and were retained as pseudomorphism pyrites.The size of framboidal pyrites precipitated in cold seeps can be used to trace the redox environment;however,acquisition of additional data via investigation of different cold seeps is necessary to obtain more persuasive results.

Ice sheet controls on fine-grained deposition at the southern Mendeleev Ridge since the penultimate interglacial

Clay minerals deposited at the southern Mendeleev Ridge in the Arctic Ocean have a unique provenance,which can be used to reconstruct changes in the local sedimentary environment.We show that sediments in core ARC7-E23 record high-frequency changes in clay minerals since the penultimate interglacial.The clay minerals,grain size,and ice-rafted debris indicate the extent of the East Siberia Ice Sheet(ESIS).During the glacial periods of Marine Isotope Stage 2(MIS2)and MIS4,the southern Mendeleev Ridge was likely covered by an ESIS-extended ice shelf,blocking almost all sediment input from the Canadian Arctic and Laptev Sea,but allowing transport of fine-grained sediments from the East Siberian and Chukchi Sea shelves.After ESIS retreat,the Beaufort Gyre and Transpolar Drift became the primary transport mechanism for the distally sourced sediments.Climate conditions in MIS3 enhanced both the oceanic circulation and sediment transport.

P2 asymmetry of Au's M-band flux and its smoothing effect due to high-Z ablator dopants

X-ray drive asymmetry is one of the main seeds of low-mode implosion asymmetry that blocks further improvement of the nuclear per-formance of“high-foot”experiments on the National Ignition Facility[Miller et al.,Nucl.Fusion 44,S228(2004)].More particularly,the P2 asymmetry of Au's M-band flux can also severely influence the implosion performance of ignition capsules[Li et al.,Phys.Plasmas 23,072705(2016)].Here we study the smoothing effect of mid-and/or high-Z dopants in ablator on Au's M-band flux asymmetries,by modeling and comparing the implosion processes of a Ge-doped ignition capsule and a Si-doped one driven by X-ray sources with P2 M-band flux asymmetry.As the results,(1)mid-or high-Z dopants absorb hard X-rays(M-band flux)and re-emit isotropically,which helps to smooth the asymmetric M-band flux arriving at the ablation front,therefore reducing the P2 asymmetries of the imploding shell and hot spot;(2)the smoothing effect of Ge-dopant is more remarkable than Si-dopant because its opacity in Au's M-band is higher than the latter's;and(3)placing the doped layer at a larger radius in ablator is more efficient.Applying this effect may not be a main measure to reduce the low-mode implosion asymmetry,but might be of significance in some critical situations such as inertial confinement fusion(ICF)experiments very near the performance cliffs of asymmetric X-ray drives.

Petrology and geochemistry of cold seep carbonates from the northern Okinawa Trough,East China Sea:implications to early diagenesis

Carbonate samples were collected from the northern Okinawa Trough in the East China Sea in 2013.The petrology,mineralogy,carbon and oxygen isotopes,and rare earth elements(REEs)of these samples were analyzed.Aragonite,high-Mg calcite,and dolomite were the main carbonate minerals,the contents of which varied greatly among the carbonate samples.Petrological observations revealed the common occurrence of framboidal pyrites.Theδ^(13)C values of carbonates varied from-53.7‰to-39.3‰(average of-47.3‰based on Vienna Pee Dee Belemnite(V-PDB),n=9),and theδ^(18)O values ranged from 0.6‰to 3.4‰(average of 1.9‰;V-PDB,n=9).The carbon and oxygen isotope characteristics indicated that the carbonates precipitated during the anaerobic oxidation of methane.The carbon source was a mixture of thermogenic methane and biogenic methane,possibly with a greater contribution from the former.The oxygen isotope data showed that gas hydrate dissociation occurred during carbonate precipitation.The Ce anomalies suggested that the carbonates precipitated in an anoxic environment.A slight enrichment of middle REEs(MREEs)could be attributable to the early diagenesis.The structures,minerals,oxygen isotopes,and MREEs all indicated that the carbonates experienced some degree of early diagenesis.Therefore,the infl uence of early diagenesis should be considered when using geological and geochemical proxies to reconstruct original methane seepage environments.

First demonstration of improving laser propagation inside the spherical hohlraums by using the cylindrical laser entrance hole

The octahedral spherical hohlraums have natural superiority in maintaining high radiation symmetry during the entire capsule implosion process in indirect drive inertial confinement fusion.While,in contrast to the cylindrical hohlraums,the narrow space between the laser beams and the spherical hohlraum wall is usually commented.In this Letter,we address this crucial issue and report our experimental work conducted on the SGIII-prototype laser facility which unambiguously demonstrates that a simple design of cylindrical laser entrance hole(LEH)can dramatically improve the laser propagation inside the spherical hohlraums.In addition,the laser beam deflection in the hohlraum is observed for the first time in the experiments.Our 2-dimensional simulation results also verify qualitatively the advantages of the spherical hohlraums with cylindrical LEHs.Our results imply the prospect of adopting the cylindrical LEHs in future spherical ignition hohlraum design.

Acknowledgement to reviewers

In 2020,Matter and Radiation at Extremes(MRE)reached a particularly important milestone when it received its first official impact factor of 2.931,which indicates the high quality of the papers published to date.This outstanding success can be attributed to the strong commitment and valuable contributions from all the reviewers.The Editors of MRE wish to express their deepest gratitude to the following individuals who generously provided advice on manuscripts as reviewers for MRE in the year of 2020.

Dynamics of particles near the surface of amedium under ultra-strong shocks

Through nonequilibrium molecular dynamics simulations,we provide an atomic-scale picture of the dynamics of particles near the surface of a medium under ultra-strong shocks.This shows that the measured surface velocity v_(f)under ultra-strong shocks is actually the velocity of the critical surface at which the incident probe light is reflected,and v_(f)has a single-peaked structure.The doubling rule commonly used in the case of relatively weak shocks to determine particle velocity behind the shock front is generally not valid under ultra-strong shocks.After a short period of acceleration,v_(f)exhibits a long slowly decaying tail,which is not sensitive to the atomic mass of the medium.A scaling law for v_(f)is also proposed,and this may be used to improve the measurement of particle velocity u in future experiments.

Matter and radiation at extremes:Prospects and impacts

High-energy-density science(HEDS)has been recognized as a comprehensive new area of physical science,with the potential to revolutionize various scientific and technological fields,including nuclear fusion,particle acceleration,astrophysics,and the properties of condensed matter under extreme conditions.That is why this journal,Matter and Radiation at Extremes(MRE),was established five years ago by the China Academy of Engineering Physics(CAEP)with the mission of informing the worldwide scientific community about progress related to HEDS,whether this be in the basic physics.

Progress and prospect

With a goal of establishing a leading-edge international journal and an influential platform for researchers investigating physical principles,technologies,and applications of the emerging field of high energy density science,we initiated the new journal,Matter and Radiation at Extremes(MRE)in 2016.MRE has been and will be dedicated to report extreme states of matter and radiation and the related science,technology,and applications,including drivers(lasers,pulsed power,accelerators),modeling tools,targets,and diagnostics that are employed to produce,understand,and diagnose these conditions in the laboratory.

Generation of a sharp density increase in radiation transport between high-Z and low-Z plasmas

A sharp density increase(referred to as density incrustation)of the Au plasmas in the radiative cooling process of high-Z Au plasmas confined by low-Z CH plasmas is found through the radiative hydrodynamic simulations.The temperature of Au plasmas changes obviously in the cooling layer while the pressure remains constant.Consequently,the Au plasmas in the cooling layer are compressed,and the density incrustation is formed.It is also shown that when the high-Z plasma opacity decreases or the low-Z plasma opacity increases,the peak density of the density incrustation becomes lower and the thickness of the density incrustation becomes wider.This phenomenon is crucial to the Ray-leigheTaylor instability at the interface of high-Z and low-Z plasmas,since the density variation of Au plasmas has a considerable influence on the Atwood number of the interface.

Coverage of 13-Valent Pneumococcal Conjugate Vaccine Among Children 0–15 Months of Age—9 Provinces,China,2019–2021

Summary What is already known on this topic?Limited data exist regarding the coverage of the 13-valent pneumococcal conjugate vaccine(PCV13)in China.A lack of official statistics,coupled with an insufficient body of published literature,hinders the accurate depiction of the current situation.What is added by this report?This study investigated the utilization of PCV13 and estimated its coverage in nine provinces across eastern,central,and western China between 2019 and 2021.Despite an annual increase in PCV13 usage during this period,the overall coverage remained suboptimal.

Theoretical and simulation research of hydrodynamic instabilities in inertial-confinement fusion implosions

Inertial fusion energy(IFE)has been considered a promising,nearly inexhaustible source of sustainable carbon-free power for the world's energy future.It has long been recognized that the control of hydrodynamic instabilities is of critical importance for ignition and high-gain in the inertial-confinement fusion(ICF)hot-spot ignition scheme.In this mini-review,we summarize the progress of theoretical and simulation research of hydrodynamic instabilities in the ICF central hot-spot implosion in our group over the past decade.In order to obtain sufficient understanding of the growth of hydrodynamic instabilities in ICF,we first decompose the problem into different stages according to the implosion physics processes.The decomposed essential physics processes that are associated with ICF implosions,such as Rayleigh-Taylor instability(RTI),Richtmyer-Meshkov instability(RMI),Kelvin-Helmholtz instability(KHI),convergent geometry effects,as well as perturbation feed-through are reviewed.Analytical models in planar,cylindrical,and spherical geometries have been established to study different physical aspects,including density-gradient,interface-coupling,geometry,and convergent effects.The influence of ablation in the presence of preheating on the RTI has been extensively studied by numerical simulations.The KHI considering the ablation effect has been discussed in detail for the first time.A series of single-mode ablative RTI experiments has been performed on the Shenguang-Ⅱlaser facility.The theoretical and simulation research provides us the physical insights of linear and weakly nonlinear growths,and nonlinear evolutions of the hydrodynamic instabilities in ICF implosions,which has directly supported the research of ICF ignition target design.The ICF hot-spot ignition implosion design that uses several controlling features,based on our current understanding of hydrodynamic instabilities,to address shell implosion stability,has been briefly described,several of which are novel.

连续流生物反应器技术在微生物培养中的应用

自然环境中99%微生物在实验室条件下仍是不能被培养的,称之为“未培养”微生物或微生物“暗物质”。对其进行研究不仅有助于认识环境中微生物代谢多样性,丰富生命之树,同时未培养微生物还蕴含着巨大的新基因和新天然产物资源。但传统培养技术的局限性阻碍了“未培养”微生物资源的开发和利用。虽然随着分子生物学技术的发展,可以直接从环境中获得未培养微生物的遗传信息,分析微生物的广泛代谢多样性,但微生物的生理特征和代谢产物等分析仍然需要建立在研究纯菌株的基础上。目前,已经有很多新颖的培养技术被研发,如原位培养技术、共培养技术和连续流生物反应器培养技术等用于挖掘未培养微生物资源。本文主要介绍了连续流生物反应器培养新技术的发展与改进,探讨了“未培养”微生物培养技术及设备的发展方向,以进一步促进“未培养”微生物资源的开发与利用。

Geochemical characteristics and metal element enrichment in crusts from seamounts of the Western Pacific

Elemental geochemistry is an essential part of understanding mineralization mechanisms. In this paper, a data set of 544 cobalt crust samples from seamounts of the Western Pacific are used to study the enrichment characteristics of metal elements. REE normalization is utilized to reveal the origin of the crusts; effects of water depth on Co enrichment and impacts ofphosphatization on mineral quality are discussed to obtain the evolution of these marine mineral deposits, which gives support to further resource assessment. Conclusions are reached as follows： 1） Elemental abundances, inter-element relation- ships, and shale-normalized REE patterns for phosphate- poor crusts from different locations reflect hydrogenetic origin of the crusts. EFs （enrichment coefficients） of REE exhibit exponential increase from surface sediments to phosphorite to polymetallic nodules to crusts, suggesting that the improved degree of hydrogeneous origin induces the enrichment of REE. 2） The crusts in the Western Pacific, formed through hotspot produced guyots trails, have relatively lower REE than those in the Mid-Pacific. The latter could be attributed to the peculiar submarine topography of seamounts formed by intraplate volcanism. 3） The non-phosphatized younger crust layers have 40% higher Co than the phosphatized older layers. This indicates the modification of the elemental composition in these crusts by phosphatization. A general depletion of hydroxide-dominated elements such as Co, Ni, and Mn and enrichment of P, Ca, Ba, and Sr is evident in phosphatized crusts, whereas non-phosphatized younger generation crusts are rich in terrigenous aluminosilicate detrital matter. 4） Co increases above the carbonate compensation depth （CCD） from less than 0.53% to over 0.65% in seamount regions with water depth of less than 2,500 m, suggesting the significance of the dissolution of carbonate in the sea water column to the growth and composition of crusts.

Norditerpenoids biosynthesized by variediene synthase-associated P450 machinery along with modifications by the host cell Aspergillus oryzae

The chemical diversity of terpenoids is typically established by terpene synthase-catalyzed cyclization and diversified by post-tailoring modifications.Fungal bifunctional terpene synthase(BFTS)associated P450 enzymes have shown significant catalytic potentials through the development of various new terpenoids with different biological activities.This study discovered the BFTS and its related gene cluster from the plant endophytic fungus Didymosphaeria variabile 17020.Heterologous expression of the BFTS in Saccharomyces cerevisiae resulted in the characterization of a major product diterpene variediene(1),along with two new minor products neovariediene and neoflexibilene.Further heterologous expression of the BFTS and one cytochrome P450 enzyme VndE(CYP6138B1)in Aspergillus oryzae NSAR1 led to the identification of seven norditerpenoids(19 carbons)with a structurally unique 5/5 bicyclic ring system.Interestingly,in vivo experiments suggested that the cyclized terpene variediene(1)was modified by VndE along with the endogenous enzymes from the host cell A.oryzae through serial chemical conversions,followed by multi-site hydroxylation via A.oryzae endogenous enzymes.Our work revealed that the two-enzymes biosynthetic system and host cell machinery could produce structurally unique terpenoids.