Satellite-observed significant improvement in nearshore transparency of the Bohai Sea during pollution control

The Bohai Sea(BS)is the unique semi-closed inland sea of China,characterized by degraded water quality due to significant terrestrial pollution input.In order to improve its water quality,a dedicated action named“Uphill Battles for Integrated Bohai Sea Management”(UBIBSM,2018–2020)was implemented by the Chinese government.To evaluate the action effectiveness toward water quality improvement,variability of the satelliteobserved water transparency(Secchi disk depth,Z_(SD))was explored,with special emphasis on the nearshore waters(within 20 km from the coastline)prone to terrestrial influence.(1)Compared to the status before the action began(2011–2017),majority(87.3%)of the nearshore waters turned clear during the action implementation period(2018–2020),characterized by the elevated Z_(SD)by 11.6%±12.1%.(2)Nevertheless,the improvement was not spatially uniform,with higher Z_(SD)improvement in provinces of Hebei,Liaoning,and Shandong(13.2%±16.5%,13.2%±11.6%,10.8%±10.2%,respectively)followed by Tianjin(6.2%±4.7%).(3)Bayesian trend analysis found the abrupt Z_(SD)improvement in April 2018,which coincided with the initiation of UBIBSM,implying the water quality response to pollution control.More importantly,the independent statistics of land-based pollutant discharge also indicated that the significant reduction of terrestrial pollutant input during the UBIBSM action was the main driver of observed Z_(SD)improvement.(4)Compared with previous pollution control actions in the BS,UBIBSM was found to be the most successful one during the past 20 years,in terms of transparency improvement over nearshore waters.The presented results proved the UBIBSM-achieved remarkable water quality improvement,taking the advantage of long-term consistent and objective data record from satellite ocean color observation.

Key CO_(2)capture technology of pure oxygen exhaust gas combustion for syngas-fueled high-temperature fuel cells

Integrated gasification fuel cells(IGFCs)integrating high-temperature solid oxide fuel cell technology with CO_(2)capture processes represents highly-efficient power systems with negligible CO_(2)emissions.Flame burning with pure oxygen is an ideal method for fuel cell exhaust gas treatment,and this report describes experimental and numerical studies regarding an oxy-combustor for treating the exhaust gas of a 10 kW IGFC system anode.The applied simulation method was verified based on experiments,and the key performance indices of the combustor were studied under various conditions.It was determined that 315 K was the ideal condensation temperature to obtain flame stability.Under these pure oxygen flame burning conditions,CO was almost completely converted,and the dry mole fraction of CO_(2)after burning was C 0.958 when there was up to 5%excess O_(2).Overall,5%excess O_(2)was recommended to maximize CO_(2)capture and promote other environmental considerations.Additionally,the optimal tangential fuel jet angle to control the liner temperature was approximately 25°.The total fuel utilization had to be high enough to maintain the oxygen flame temperature of the anode exhaust gas below 1800 K to ensure that the system was environmentally friendly.The results presented herein have great value for designing IGFCs coupled with CO_(2)capture systems.

Design of two-stage membrane reactor for the conversion of coke-oven gas to H_2 and CO

The catalyst function was achieved in two regions in an oxygen permeation membrane reactor： H2 dissociated and reacted with lattice oxygen or oxygen ions to form H20 near the membrane surface. The H20 formed could react with the residual CH4 away from the membrane surface area.

Development of catalytic combustion and CO_(2)capture and conversion technology

Changes are needed to improve the efficiency and lower the CO_(2)emissions of traditional coal-fired power generation,which is the main source of global CO_(2)emissions.The integrated gasification fuel cell(IGFC)process,which combines coal gasification and high-temperature fuel cells,was proposed in 2017 to improve the efficiency of coal-based power generation and reduce CO_(2)emissions.Supported by the National Key R&D Program of China,the IGFC for nearzero CO_(2)emissions program was enacted with the goal of achieving near-zero CO_(2)emissions based on(1)catalytic combustion of the flue gas from solid oxide fuel cell(SOFC)stacks and(2)CO_(2)conversion using solid oxide electrolysis cells(SOECs).In this work,we investigated a kW-level catalytic combustion burner and SOEC stack,evaluated the electrochemical performance of the SOEC stack in H2O electrolysis and H2O/CO_(2)co-electrolysis,and established a multiscale and multi-physical coupling simulation model of SOFCs and SOECs.The process developed in this work paves the way for the demonstration and deployment of IGFC technology in the future.

Application of Solar Photovoltaic Water Pumping System in Hainan Agriculture

With radical socio-economic development and strengthening of regulation of agricultural industrial structure in Hainan Province,fresh water resource becomes increasingly insufficient.Existing water-saving facilities and measures are unable to promote sustainable and stable development of local economy.This needs modern irrigation method.Solar photovoltaic water pumping system is necessary and feasible in Hainan agriculture,and will have directive significance for Hainan Province developing photovoltaic agriculture.

Improved ferroelectric properties of CMOS back-end-of-line compatible Hf_(0.5)Zr_(0.5)O_(2)thin films by introducing dielectric layers

Hf_(0.5)Zr_(0.5)O_(2)(HZO)ferroelectric thin films have gained significant attention for the development of next-generation ferroelectric memories by complementary-metal-oxide semiconductor(CMOS)back-end-of-line(BEOL)processing,due to their relatively low crystallization temperature.However,it remains challenging to achieve excellent ferroelectric properties with post deposition annealing(PDA)process at a BEOL compatible temperature.Along these lines,in this work,it is demonstrated that the ferroelec-tricity of 15 nm thick HZO thin film prepared by PDA process at 400℃can be improved to varying degrees,via depositing 2 nm thick dielectric layers of Al_(2)O_(3),HfO_(2),or ZrO_(2)at either the bottom or the top of the film.Notably,the HZO thin film with the top-Al_(2)O_(3)layer exhibits remarkable ferroelectric prop-erties,which are independent of the thickness of HZO.The 6 nm thick HZO thin film shows a total remanent polarization(2Pr)of 31 mC/cm^(2)under an operating voltage of 2.5 V.These results represent a significant advancement in the fabrication of high-performance,BEOL compatible ferroelectric mem-ories,as compared to previously reported state-of-the-art works.

Whole exome sequencing and functional validation identify CAPN1 variants as a cause of Chinese moyamoya disease

Moyamoyadisease(MMD,MIM607151)is a rarevascular condition that has high recurrence,mortality,and disability rates,and an effective treatment for this disease is currently lacking.The main symptoms of affected children and adults include ischemic and hemorrhagic strokes,with an age of onset that follows a bimodal distribution trend at approximately 5 and 40 years of age.

靶向钝化与界面载流子动力学优化以提高无空穴传输层的窄带隙钙钛矿太阳电池的效率和稳定性

窄带隙锡-铅混合钙钛矿太阳电池(PSCs)的效率有望接近Shockley-Queisser极限,然而,易氧化的亚锡离子Sn^(2+)以及载流子传输层/钙钛矿未优化的界面接触会导致严重的界面电荷复合和器件性能下降,这在很大程度上阻碍了锡-铅混合钙钛矿太阳电池的实际应用,本文通过在钙钛矿中掺入少量有机膦酸咔唑分子,成功地制备了无空穴传输层锡-铅混合钙钛矿太阳电池.相对于Pb^(2+),有机磷酸咔唑分子在晶界处和晶体表面与Sn^(2+)离子有更强的化学配位作用,从而有效抑制Sn^(2+)的氧化,钝化缺陷并抑制非辐射复合。在移除空穴传输层的情况下,此类有机膦酸咔唑分子靶向修饰作用可有效增强内建电场(~100mV),优化透明导电基底与钙钛矿层的能级排列,从而加速光生电荷分离,促进界面空穴抽取和传输.最终,无空穴传输层的锡-铅混合钙钛矿太阳电池获得最高20.21%的光电转换效率,开路电压高达0.87V,同时实现了超过2400小时的长期稳定性。

原发性舌鳞癌MRI浸润深度与病理浸润深度的相关性研究

目的:探讨原发性舌鳞状细胞癌(tongue squamous cell carcinoma,TSCC)的术前磁共振浸润深度(MRI depth of invasion,MRI-DOI)与术后病理浸润深度(pathologic DOI,p-DOI)之间的相关性。方法:回顾性选取2015年1月至2018年12月上海交通大学医学院附属第九人民医院经病理证实的TSCC患者入组,测量p-DOI,分析p-DOI与患者临床病理参数及预后的关系,进一步回顾性测量MRI-DOI,研究MRI-DOI与p-DOI之间的相关性。结果:入组患者共52例,p-DOI为1~30 mm,平均值(8.5±5.5)mm;p-DOI>5 mm时,P-DOI与肿瘤大小(P=0.021)、肿瘤部位(P=0.047)显著相关;p-DOI≥10 mm时,p-DOI与颈部Ⅲ区淋巴结转移显著相关(P=0.010);p-DOI>7 mm时,与患者的5年生存率最密切相关(P=0.048)。MRI-DOI为3.1~19.9 mm,平均值为(10.3±4.3)mm;MRI-DOI≥10 mm时,与原发性舌鳞癌患者的不良预后密切相关(P=0.043)。MRI-DOI测量值总体略高于p-DOI,平均差值为1.94 mm,相关性较强(r=0.831,P<0.001)。结论:基于MRI的术前放射学DOI测量有助于估计TSCC的术后p-DOI,有助于术前预测肿瘤的侵袭深度,对原发性舌鳞癌外科手术方式的制定及预后评估具有重要的参考价值。

Towards a verified compiler prototype for the synchronous language SIGNAL

SIGNAL belongs to the synchronous languages family which are widely used in the design of safety-critical real-time systems such as avionics, space systems, and nu- clear power plants. This paper reports a compiler prototype for SIGNAL. Compared with the existing SIGNAL com- piler, we propose a new intermediate representation （named S-CGA, a variant of clocked guarded actions）, to integrate more synchronous programs into our compiler prototype in the future. The front-end of the compiler, i.e., the transla- tion from SIGNAL to S-CGA, is presented. As well, the proof of semantics preservation is mechanized in the theo- rem prover Coq. Moreover, we present the back-end of the compiler, including sequential code generation and multi- threaded code generation with time-predictable properties. With the rising importance of multi-core processors in safety- critical embedded systems or cyber-physical systems （CPS）, there is a growing need for model-driven generation of multi- threaded code and thus mapping on multi-core. We propose a time-predictable multi-core architecture model in archi- tecture analysis and design language （AADL）, and map the multi-threaded code to this model.

A hybrid carbon aerogel with both aligned and interconnected pores as interlayer for high-performance lithium-sulfur batteries

The soluble nature of polysulfide species created on the sulfur electrode has severely hampered the electrochemical performance of lithium-sulfur （Li-S） batteries. Trapping and anchoring polysulfides are promising approaches for overcoming this issue. In this work, a mechanically robust, electrically conductive hybrid carbon aerogel （HCA） with aligned and interconnected pores was created and investigated as an interlayer for Li-S batteries. The hierarchical cross-linked networks constructed by graphene sheets and carbon nanotubes can act as an ＂internet＂ to capture the polysulfide, while the micro- and nano-pores inside the aerogel can facilitate quick penetration of the electrolyte and rapid transport of lithium ions. As advantages of the unique structure and excellent accommodation of the volume change of the active materials, a high specific capacity of 1,309 mAh.g-1 at 0.2 C was achieved for the assembled Li-S battery, coupled with good rate performance and long-term cycling stability （78% capacity retention after 600 cycles at 4 C）.

A comparative study of two formal semantics of the SIGNAL language

SIGNAL is a part of the synchronous languages family, which are broadly used in the design of safety-critical real-time systems such as avionics, space systems, and nu- clear power plants. There exist several semantics for SIG- NAL, such as denotational semantics based on traces （called trace semantics）, denotational semantics based on tags （called tagged model semantics）, operational semantics presented by structural style through an inductive definition of the set of possible transitions, operational semantics defined by syn- chronous transition systems （STS）, etc. However, there is lit- tle research about the equivalence between these semantics. In this work, we would like to prove the equivalence be- tween the trace semantics and the tagged model semantics, to get a determined and precise semantics of the SIGNAL language. These two semantics have several different defini- tions respectively, we select appropriate ones and mechanize them in the Coq platform, the Coq expressions of the abstract syntax of SIGNAL and the two semantics domains, i.e., the trace model and the tagged model, are also given. The dis- tance between these two semantics discourages a direct proof of equivalence. Instead, we transform them to an intermediate model, which mixes the features of both the trace semantics and the tagged model semantics. Finally, we get a determined and precise semantics of SIGNAL.

Centimeter-scale growth of two-dimensional layered high-mobility bismuth films by pulsed laser deposition

Ever since discovery of graphene,two-dimensional(2D)materials become a new tool box for information technology.Among the 2D family,ultrathin bismuth(Bi)has attracted a great deal of attention in recent years due to its unique topological insulating properties and large magnetoresistance.However,the scalable synthesis of layered Bi ultrathin films is rarely been reported,which would greatly restrict further fundamental investigation and practical device development.Here,we demonstrate the direct growth of homogeneous and centimeter-scale layered Bi films by pulsed laser deposition(PLD)technique.The as-grown Bi film exhibits high-purity phase and good crystallinity.In addition,both(111)and(110)-oriented Bi films can be synthesized by precisely controlling the processing temperature.The characterization of optical properties shows a thickness dependent band gaps(0.075-0.2 eV).Moreover,Bi thin-film-based field-effect transistors have been demonstrated,exhibiting a large carrier mobility of 220 cm2 V−1 s−1.Our work suggests that the PLD-grown Bi films would hold the potential to develop spintronic applications,electronic and optoelectronic devices used for information science and technology.

Towards a simple and safe Objective Caml compiling framework for the synchronous language SIGNAL

This paper presents a simple and safe compiler, called MinSIGNAL, from a subset of the synchronous dataflow language SIGNAL to C, as well as its existing en? hancements. The compiler follows a modular architecture, and can be seen as a sequence of source-to-source transformations applied to an intermediate representation which is named Synchronous Clocked Guarded Actions (S-CGA) and translation to sequential imperative code. Objective Caml (OCaml) is used for the implementation of MinSIGNAL. As a modem functional language, OCaml is adapted to symbolic computation and so, particularly suitable for compiler design and implementation of formal analysis tools. In particular, the safety of its type checking allows to skip some verification that would be mandatory with other languages. Additionally, this work is a basis for the formal verification of the compilation of SIGNAL with a theorem prover such as Coq.

Cell-protecting regeneration from anode carbon deposition using in situ produced oxygen and steam:A combined experimental and theoretical study

Carbon deposition is a primary concern during the operation of solid oxide fuel cells（SOFCs） fueled with hydrocarbon fuels, leading to cell degradation and even cell damage. Carbon elimination is expected to be a promising approach to prolong cell life. This work reports on a combined experimental and theoretical investigation of cell regeneration from anode carbon deposition of tubular SOFCs fabricated by phase-inversion and co-sintering techniques. The as-prepared cell exhibits a maximum power density of 0.20 W cm;at 800 ℃ fueling with wet CH;, but fails to stable operation due to severe carbon deposition.Based on thermodynamic predictions, a successive cell-protecting regeneration process is proposed to eliminate deposited carbon without oxidizing Ni catalysts, during which CH;and H;fuels are provided in circulation. Through a total of 35 cycling tests, cell performance can always successfully restore to the initial level.The possible carbon elimination mechanism is investigated in detail based on thermodynamic and first-principle calculations. The feasibility of carbon elimination using in situ produced oxygen or steam through electrochemical reaction has been revealed, providing a novel continuous operation mode for hydrocarbon-based SOFCs.

Evaluation of La_(0.7)Ca_(0.3)Cr_(0.95)Zn_(0.05)O_(3-δ)-Gd_(0.1)Ce_(0.9)O_(2-δ) Dual-phase Material and its Potential Application in Oxygen Transport Membrane

In this work, a dual-phase material consisting Gd0.1Ce0.9O2-δ （GDC, 60 wt%） was synthesized. of La0.7Ca0.3Cr0.95Zn0.05O3-δ （LCCZ, 40 wt%） and Properties including phase structure, sintering behavior, electrical conductivity and oxygen permeability for LCCZ-GDC were evaluated. The results show that dense LCCZ-GDC dual-phase disks were obtained at the sintering temperature of 1250, 1300, 1350 and 1400 ℃ by tape casting and high temperature sintering method. The grain sizes of both GDC and LCCZ grew up with the increasing of sintering temperature. The average grain size of GDC was about 0.5, 0.8, 1.4, 1.8 μm while the average grain size of LCCZ was about 0.8, 1.5, 1.8 and 2 pm after sintering at 1250, 1300, 1350 and 1400℃, respectively. Oxygen flux of LCCZ-GDC decreased with the increase of sintering temperature from 1250 to 1400 ℃. The oxygen flux of LCCZ-GDC sintered at 1250 ℃ reached 0.079 mL/min/cm2 at 975℃ with a membrane thickness of 800 μm. Dual-phase material of LCCZ-GDC will be a promising oxygen transport membrane material for its low sintering temperature and good microstructure.

Multi-threaded code generation from Signal program to OpenMP

The use of multi-core processors will become a trend in safety critical systems. For safe execution of multi- threaded code, automatic code generation from formal spec- ification is a desirable method. Signal, a synchronous lan- guage dedicated for the functional description of safety crit- ical systems, provides soundness semantics for determinis- tic concurrency. Although sequential code generation of Sig- nal has been implemented in Polychrony compiler, deter- ministic multi-threaded code generation strategy is still far from mature. Moreover, existing code generation methods use certain multi-thread library, which limits the cross plat- form executions. OpenMP is an application program inter- face （API） standard for parallel programming, supported by several mainstream compilers from different platforms. This paper presents a methodology translating Signal program to OpenMP-based multi-threaded C code. First, the intermedi- ate representation of the core syntax of Signal using syn- chronous guarded actions is defined. Then, according to the compositional semantics of Signal equations, the Signal pro- gram is synthesized to dependency graph （DG）. After par- allel tasks are extracted from dependency graph, the Signal program can be finally translated into OpenMP-based C code which can be executed on multiple platforms.

Electrochemical Properties of Tubular SOFC Based on a Porous Ceramic Support Fabricated by Phase-Inversion Method

In this work, a tubular ceramic-supported solid oxide fuel cell （SOFC） was successfully fabricated by a low cost and simple process involving phase-inversion, brush coating and co-sintering. Properties in- cluding sintering behavior, microstructure of the tubular support as well as the electrochemical properties of single cell were investigated. The results show that a porous tubular support with finger-like pores and macrovoids was obtained after phase-inversion process. The tubular support is proved to be gaspermeable after sintering at 1400 ℃ with shrinkage of about 34%. The maximum power density of single tubular SOFC is 100 mW/cm2 and 122 mW/cm2 at 850 ℃ when fed with wet methane and hydrogen, respectively. The current collection, thickness of electrolyte and gas permeability of tubular support should account for the large total resistance. The present tubular design could be expected to deliver a higher voltage for longer support with several segmented-in-series cell stacks.

A survey on formal specification and verification of separation kernels

Abstract Separation kernels are fundamental software of safety and security-critical systems, which provide their hosted applications with spatial and temporal separation as well as controlled information flows among partitions. The application of separation kernels in critical domain demands the correctness of the kernel by formal verification. To the best of our knowledge, there is no survey paper on this topic. This paper presents an overview of formal specification and verification of separation kernels. We first present the back- ground including the concept of separation kernel and the comparisons among different kernels. Then, we survey the state of the art on this topic since 2000. Finally, we summa- rize research work by detailed comparison and discussion.

Fabrication and optimization of La_(0.4)Sr_(0.6)Co_(0.2)Fe_(0.7)Nb_(0.1)O_(3-δ) electrode for symmetric solid oxide fuel cell with zirconia based electrolyte

La（0.4）Sr（0.6）Co（0.2）Fe（0.7）Nb（0.1）O（3-δ）（LSCFN）was applied as both anode and cathode for symmetrical solid oxide fuel cells（SSOFCs）with zirconia based electrolyte.The cell with LSCFN electrode was fabricated by tape-casting and screen printing.Fabrication process was optimized firstly by comparing co-sintering and separate-sintering of electrode and electrolyte.To further improve the LSCFN electrode properties,oxygen ionic conductor of Gd（0.1）Ce（0.9）O（2-δ）（GDC）was added into the LSCFN electrode.The preferred composition of LSCFN-GDC composite electrode was found to be 1：1 in weight ratio with polarization resistance of 0.16Ωcm^2at 800~℃.The maximum power densities of LSCFN-GDC｜｜GDC/YSZ/GDC｜｜LSCFN-GDC tested in H2and CH4with 3%H2O were 395 m W cm^（-2）and 124 m W cm^（-2）at 850~？C,respectively,which were much higher than that of LSCFN｜｜GDC/YSZ/GDC｜｜LSCFN cells at same condition,possibly due to the extension of the triple phase boundary induced by the addition of GDC.The cell showed reasonable stability using H2and CH4with 3%H2O as fuels and no significant power output degradation was observed after total 200 h operation.