Hole-Doped Nonvolatile and Electrically Controllable Magnetism in van der Waals Ferroelectric Heterostructures

Electrical control of magnetism in van der Waals semiconductors is a promising step towards development of two-dimensional spintronic devices with ultralow power consumption for processing and storing information.Here, we propose a design for two-dimensional van der Waals heterostructures(vdWHs) that can host ferroelectricity and ferromagnetism simultaneously under hole doping. By contacting an In Se monolayer and forming an InSe/In_(2)Se_(3) vd WH, the switchable built-in electric field from the reversible out-of-plane polarization enables robust control of the band alignment. Furthermore, switching between the two ferroelectric states(P_↑ and P_↓)of hole-doped In_(2)Se_(3) with an external electric field can interchange the ON and OFF states of the nonvolatile magnetism. More interestingly, doping concentration and strain can effectively tune the magnetic moment and polarization energy. Therefore, this provides a platform for realizing multiferroics in ferroelectric heterostructures,showing great potential for use in nonvolatile memories and ferroelectric field-effect transistors.

废铁屑制备三草酸合铁酸钾虚实结合的综合化学实验设计

将无机化学中的两个制备实验(硫酸亚铁铵的制备、三草酸合铁酸钾的制备)和分析化学中的组成分析实验(铁离子、草酸根离子和结晶水含量测定)进行综合,设计了一个综合化学实验。在制备部分引入线上虚拟操作和线下自主设计环节,分析部分不仅使用了传统的化学分析法,同时引入红外光谱仪(IR)和X射线衍射仪(XRD)对产品进行表征分析。通过该实验的实施,可使学生进一步巩固减压过滤、重结晶、滴定等基本实验操作技能;掌握利用大型仪器对产品的组成和结构进行表征的方法;锻炼学生综合应用化学理论知识解决实践问题的能力。同时结合思政教育,有助于培养学生的安全环保意识和科学探索精神,提高学生的实验责任心和对化学学科的兴趣。

应用微通道反应器技术成对电合成葡萄糖酸锌和山梨醇

“电化学氧化葡萄糖制备葡萄糖酸锌”是一个本科生有机电合成实验,通常使用H型电解池作为反应器,存在着合成时间长、合成电压高、电流效率低等缺点。电化学微通道反应器可降低合成电压、有效增强传质。本实验以培养学生的独立思考和逻辑思维能力为导向,将这个实验改进为一个综合化学实验,通过自制的电化学微通道反应器进行成对电合成葡萄糖酸锌和山梨醇。教学过程中首先向学生介绍相关原理和基础知识,继而引导学生应用循环伏安法选择合适的合成电压,然后组装反应器进行成对电合成,最后进行产物的分离和鉴别并展开分析和讨论。通过本实验,学生将理解循环伏安法等电分析方法为什么能为电合成提供指导信息,理解成对电合成的优点,了解电化学微通道反应器新技术的应用优势,了解电化学合成与绿色化学的关系。本改进实验教学内容丰富,涉及电合成、电分析、滴定分析等多个典型实验技能,有助于学生在分析问题、解决问题的过程中培养科学思维和创新能力。

金属β-内酰胺酶L1的制备和动力学表征线上线下混合实验

蛋白质的基因克隆与表达是许多化学生物学实验的重要内容,但因原理概念抽象、操作步骤多、耗时长的缺点限制了其在常规本科实验教学中的有效开展。基于本科化学生物学创新实验“金属β-内酰胺酶L1的制备和动力学表征”,对原实验教学内容与教学方式进行了创新性改进。主要改进包括:(1)利用移动设备进行金属β-内酰胺酶L1的制备及表征线上虚拟仿真实验,含聚合酶链反应扩增目的基因、重组质粒转化感受态细胞、蛋白诱导表达等10个模块。线上高仿真实验场景和人机交互性操作给学生提供高度沉浸感实验体验,集中连贯的实验教学使知识构架更清晰、更完整。(2)针对重点实验及拓展实验进行线下课堂操作,新增等温滴定微量热法表征酶活线下拓展实验。该混合教学模式实现了虚实结合、线上线下融合,既拓宽了学生的视野,培养了动手能力和创新意识,也提高了教学质量和课程管理,在实践中取得了较好的反馈,可为其他院校本科实验教学提供参考。

Twist 1 correlates with poor differentiation and progression in gastric adenocarcinoma via elevation of FGFR2 expression

AIM:To explore the correlation between Twist-related protein(Twist)1,fibroblast growth factor receptor(FGFR)2 and gastric adenocarcinoma differentiation and progression.METHODS:We evaluated Twist1 and FGFR2 in 52 gastric adenocarcinoma samples by immunohistochemistry and quantitative real time polymerase chain reaction,and analyzed the correlation between Twist1,FGFR2 and cancer differentiation.We also detected Twist1 and FGFR2 expression in gastric adenocarcinoma cell lines,and evaluated Twist1 influence on FGFR2 expression.In addition,we studied the role of FGFR2 in Twist1-promoted cancer progression,including proliferation,invasion and epithelial-mesenchymal transition(EMT).RESULTS:Twist1 and FGFR2 were detected in almost all the gastric adenocarcinoma samples.Twist1(P=0.0213)and FGFR2(P=0.0310)m RNA levels had a significant association with gastric adenocarcinoma differentiation.Moreover,Twist1 and FGFR2 expression in poorly differentiated cells(SNU-1 and SNU-16)was notably higher than in well-differentiated cells(MKN-7 and MKN-28).In poorly differentiated gastric adenocarcinomas,FGFR2 m RNA level was significantly positively correlated with Twist1 m RNA level(P=0.004).Twist1 was proved to promote FGFR2 by regulating Twist1 expression by knockdown and overexpression.Additionally,Twist1 could induce proliferation,invasion and EMT in gastric cancer;of these,FGFR2 was required for invasion and EMT,rather than proliferation.CONCLUSION:Twist1 and FGFR2 are highly associated with differentiation of gastric adenocarcinoma;Twist1 can facilitate invasion and EMT in gastric adenocarcinoma via promotion of FGFR2 expression.

Relationship between excessive erythrocytosis and acute mountain sickness: A field study

Background: Alterations in hematology, especially erythroid changes, may be involved in acute mountain sickness(AMS) at high altitude. This study aimed to identify the relationship between excessive erythrocytosis and AMS following different durations of high-altitude exposure.Methods: A total of 692 healthy young Chinese men were recruited for the study in June and July of 2012 and were divided into the following five groups: I) the 24-h group(24 hours after arrival at Lhasa, 3,700 m, n=261); II) the 7-d group(exposed at Lhasa, 3,700 m for seven days, n=99); III) the re-exposure group(re-exposed at Yang Bajing, 4,400 m for seven days after >1 year of acclimation at 3,700 m, n=94); IV) the acclimated group(>1 year of acclimation at 3,700 m, Lhasa, n=42); and V) the sea-level control(control group, Chengdu, n=196). Case report forms were used to record the subjects' demographic information and AMS-related symptoms. All of the subjects underwent routine blood tests.Results: The red blood cell(RBC) count fell slightly but was not significant upon acute exposure to high altitude, whereas the hemoglobin concentration([Hb]) increased significantly. After high-altitude re-exposure, both of the [Hb] and RBC count showed significant increases. The incidence of AMS was 65.1%, 26.3% and 51.1%, respectively in the 24-h, 7-d and re-exposure groups. The [Hb](P=0.024) and hematocrit(P=0.017) were greater in the AMS+ individuals than in the AMS– individuals in 7-d group. A correlation analysis revealed that the [Hb] and hematocrit were closely related with AMS score in 7-d and re-exposure groups, while the RBC showed a correlation with AMS score only in the re-exposure group. The AMS incidence was lowest when the [Hb] was between 140 and 160 g/L in the 24-h and 7-d groups.Conclusions: AMS is associated with both [Hb] and excessive erythrocytosis. Additionally, our findings indicate the existence of an optimal [Hb] for preventing AMS.

以提升班组自主管理为导向的质量文化建设

本文介绍和分析了现阶段船舶制造企业班组建设中存在的共性问题。同时经过研究分析并结合企业实际情况,加强了对承揽公司班组质量管理,完善班组建设相关制度,落实质量实名制及质量责任,创新推进质量管理提升,加强班组全面质量管理,提高班组自主管理能力,推动了公司质量文化建设。

Diphtheria Toxin/Human B-Cell Activating Factor Fusion Protein Kills Human Acute Lymphoblastic Leukemia BALL-1 Cells: An Experimental Study

Objective： This study aimed to express a fusion protein of diphtheria toxin and human B cell-activating factor （DT388sBAFF） in Escherichia coli （E. coli） and investigate its activity in human B-lineage acute lymphoblastic leukemia 1 cells （BALL-1）. Methods： A fragment of DT388sBAFF fusion gene was separated from plasmid pUC57-DT388sBAFF digested with Nde I and Xho I, and inserted into the expression vector pcold II digested with the same enzymes. Recombinants were screened by the colony polymerase chain reaction （PCR） and restriction map. The recombinant expression vector was transformed into BL21 and its expression was induced by isopropyl β-D-1-thiogalactopyranoside （IPTG）. The recombinant protein was identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis （SDS-PAGE） and Western blot, and then purified by Ni2＋-NTA affinity chromatography. The expression level of B cell-activating factor receptor （BAFF-R） on BALL-1 cells was assessed by real-time PCR. The receptor binding capacity of recombinant protein was determined by cell fluorescent assay. The specific cytotoxicity of recombinant protein on BALL-1 cells was detected by 3-（4,5-dimethylthiazolyl-2）-2,5-diphenyltetrazolium bromide （MTT） assay. Results： The expression level of recombinant protein was 50% of total bacterial proteins in E. coli, and the recombinant protein could bind to BAFF-R-positive BALL-1 cells and thereby produce a cytotoxic effect on the cells. Conclusion： The fusion protein expression vector DT388sBAFF was successfully constructed and the recombinant protein with selective cytotoxicity against BALL-1 cells was obtained, providing foundation for further study of the therapy of human B-lineage acute lymphoblastic leukemia.

Status epilepticus as an initial manifestation of hepatic encephalopathy:A case report

BACKGROUND Status epilepticus in patients with hepatic encephalopathy (HE) is a rare butserious condition that is refractory to antiepileptic drugs, and current treatmentplans are vague. Diagnosis may be difficult without a clear history of cirrhosis.Liver transplantation (LT) is effective to alleviate symptoms, however, there arefew reports about LT in the treatment of status epilepticus with HE. To ourknowledge, this is the first report of status epilepticus present as initialmanifestation of HE.CASE SUMMARY A 59-year-old woman with a 20-year history of heavy drinking was hospitalizedfor generalized tonic-clonic seizures. She reported no history of episodes of HE,stroke, spontaneous bacterial peritonitis, ascites or gastrointestinal bleeding.Neurological examination revealed a comatose patient, without papilledema.Laboratory examination suggested liver cirrhosis. Plasma ammonia levels uponadmission were five times normal. Brain computed tomography (CT) was normal,while abdominal CT and ultrasound revealed mild ascites, liver cirrhosis andsplenomegaly. Electroencephalography (EEG)showed diffuse slow waves rhythm,consistent with HE, and sharp waves during ictal EEG corresponding to clinicalsemiology of focal tonic seizures. The symptoms were reversed by continuousantiepileptic treatment and lactulose. She was given oral levetiracetam, and focalaware seizures occasionally affected her 10 mo after LT.CONCLUSION Status epilepticus could be an initial manifestation of HE. Antiepileptic drugs combined with lactulose are essential for treatment of status epilepticus with HE,and LT is effective to prevent the relapse.

Gradient-structure-enhanced dielectric energy storage performance of flexible nanocomposites containing controlled preparation of defective TiO_(2) and ferroelectric KNbO_(3) nanosheets

Next generation power system needs dielectrics with increased dielectric energy density.However,the low energy density of dielectrics limits their development.Here,an asymmetric trilayered nanocomposite,with a transition layer(TL),an insulation layer(IL),and a polarization layer(PL),is designed based on poly(vinylidene fluoride)-polymethyl methacrylate(PVDF-PMMA)matrix using KNbO_(3)(KN)and TiO_(2)(TO)as the nanofillers.The morphology and defect control of the two-dimensional nano KN and nano TO fillers are realized via a hydrothermal method to increase the composite breakdown strength(E_(b))and the composite energy density(U_(e)).The asymmetric trilayered structure leads to a gradient electric field distribution,and the KN and TO nanosheets block charges transfer along z direction.As a result,the development path of the electrical trees is greatly curved,and E_(b) is effectively improved.And the Ue value of the nanocomposites reaches 17.79 J·cm^(-3) at 523 MV·m^(-1).On the basis,the composite Ue is further improved by defect control in TO nanosheets.The nanocomposite KN/TO/PVDF-PMMA containing TO with less oxygen vacancy concentration(calcined at oxygen atmosphere)acquires a high Ue of 21.61 J·cm^(-3) at 548 MV·m^(-1).This study provides an idea for improving the energy storage performance by combining the design of the composite dielectric structure and the control of nanofillers’defect and morphology.

Current status of municipal wastewater treatment plants in North-east China:implications for reforming and upgrading

Climate affects the natural landscape,the economic productivity of societies,and the lifestyles of its inhabitants.It also influences municipal wastewater treatment.Biological processes are widely employed in municipal wastewater treatment plants(WWTPs),and the prolonged cold conditions brought by the winter months each year pose obstacles to meeting the national standards in relatively cold regions.Therefore,both a systematic analysis of existing technical bottlenecks as well as promising novel technologies are urgently needed for these cold regions.Taking North-east China as a case,this review studied and analyzed the main challenges affecting 20 municipal WWTPs.Moreover,we outlined the currently employed strategies and research issues pertaining to low temperature conditions.Low temperatures have been found to reduce the metabolism of microbes by 58%or more,thereby leading to chemical oxygen demand(COD)and NH_(4)^(-)-N levels that have frequently exceeded the national standard during the winter months.Furthermore,the extracellular matrix tends to lead to activated sludge bulking issues.Widely employed strategies to combat these issues include increasing the aeration intensity,reflux volume,and flocculant addition;however,these strategies increase electricity consumption by>42%in the winter months.Internationally,the processes of anaerobic ammonium oxidation(anammox),granular sludge,and aerobic denitrification have become the focus of research for overcoming low temperature.These have inspired us to review and propose directions for the further development of novel technologies suitable for cold regions,thereby overcoming the issues inherent in traditional processes that have failed to meet the presently reformed WWTP requirements.

电场调控磁性的研究进展:材料、机制与器件

电控磁效应利用电场作用实现对材料磁学特性的调控,对推动低能耗、高速度、高密度自旋电子学器件的发展具有重要意义.本文将以电控磁的机制为主线展开,按照载流子调控、应变、交换耦合、轨道重构和离子迁移5种机制,从材料、性能和器件应用的角度对电场调控磁性领域的研究进展进行系统总结和归纳,以期尽量全面地为读者呈现出该领域的发展现状,并展望领域内的挑战和未来的发展方向.

RLO:一个基于强化学习的连接优化方法

连接优化是数据库领域最重要的研究问题之一.传统的连接优化方法一般应用基础启发式规则,他们通常搜索代价很高,并且很难发现最优的执行计划.主要原因有两个:(1)这些基于规则的优化方法只能探索解空间的一个子集,(2)他们没有利用历史信息,不能够很好地衡量执行计划的代价,经常重复选择相同的糟糕计划.为了解决以上两个问题,我们提出RLO(reinforcement learning optimization),一个基于强化学习的连接优化方法.我们将连接优化问题建模成马尔可夫(Markov)决策过程,并且使用深度Q-学习来估计每一种可能的执行计划的执行代价.为了进一步增强RLO的有效性,我们提出了基于树形结构的嵌入方法和集束搜索策略来尽量避免错过最好的执行计划.我们在Apache Calcite和Postgres上实现了RLO.实验表明:(1)在Apache Calcite上,与一系列剪枝的启发式算法相比,RLO搜索计划的效率为它们的10~56倍,并且生成的计划能更快地执行(80%的加速);(2)与原生的Postgres相比,RLO搜索计划的效率是其14倍,并且在端到端的执行中达到12.9%的加速.

The effect of dissolved oxygen concentration on long-term stability of partial nitrification process

Dissolved oxygen(DO)concentration is regarded as one of the crucial factors to influence partial nitrification process.However,achieving and keeping stable partial nitrification under different DO concentrations were widely reported.The mechanism of DO concentration influencing partial nitrification is still unclear.Therefore,in this study two same sequencing batch reactors(SBRs)cultivated same seeding sludge were built up with realtime control strategy.Different DO concentrations were controlled in SBRs to explore the effect of DO concentration on the long-term stability of partial nitrification process at room temperature.It was discovered that ammonium oxidation rate(AOR)was inhibited when DO concentration decreased from 2.5 to 0.5 mg/L.The abundance of Nitrospira increased from 1011.5 to 1013.7 copies/g DNA,and its relative percentage increased from 0.056%to 3.2%during 190 operational cycles,causing partial nitrification gradually turning into complete nitrification process.However,when DO was 2.5 mg/L the abundance of Nitrospira was stable and AOB was always kept at 1010.7 copies/g DNA.High AOR was maintained,and stable partial nitrification process was kept.Ammonia oxidizing bacteria(AOB)activity was significantly higher than nitrite oxidizing bacteria(NOB)activity at DO of 2.5 mg/L,which was crucial to maintain excellent nitrite accumulation performance.

Experiment and numerical simulation of melt convection and oxygen distribution in 400-mm Czochralski silicon crystal growth

Single-crystalline silicon materials with large dimensions have been widely used as assemblies in plasma silicon etching machines.However,information about large-diameter low-cost preparation technology has not been sufficiently reported.In this paper,it was focused on the preparation of 400-mm silicon（100） crystal lightly doped with boron from 28-in.hot zones.Resistivity uniformity and oxygen concentration of the silicon crystal were investigated by direct-current（DC） four-point probes method and Fourier transform infrared spectroscopy（FTIR）,respectively.The global heat transfer,melt flow and oxygen distribution were calculated by finite element method（FEM）.The results show that 28-in.hot zones can replace conventional 32 in.ones to grow 400-mm-diameter silicon single crystals.The change in crucible diameter can save energy,reduce cost and improve efficiency.The trend of oxygen distribution obtained in calculations is in good agreement with experimental values.The present model can well predict the 400-mm-diameter silicon crystal growth and is essential for the optimization of furnace design and process condition.

Numerical analysis of solid–liquid interface shape during largesize single crystalline silicon with Czochralski method

Numerical analysis is an effective tool to research the industrial Czochralski （CZ） crystal growth aiming to improve crystal quality and reduce manufactur- ing costs. In this study, a set of global simulations were carried out to investigate the effect of crystal-crucible rotation and pulling rate on melt convection and solid- liquid （SL） interface shape. Through analyses of the sim- ulation data, it is found that the interface deformation and inherent stress increase during the crystal growth process. The interface deflection increases from 7.4 to 51.3 mm with an increase in crystal size from 150 to 400 mm. In addition, the SL interface shape and flow pattern are sen- sitive to pulling rate and rotation rate. Reducing pulling rate can flat SL interface shape and add energy-consuming. Interface with low deflection can be achieved by adopting certain combination of crystal and crucible rotation rates. The effect of crystal rotation on SL interface shape is less significant at higher crucible rotation rates.

High Performance Bio-based Polyurethane Elastomers： Effect of Different Soft and Hard Segments

In this work, a series of high performance bio-based polyurethanes（bio-PUs） were synthesized from polylactide（PLA）-based diols, different diisocyanates（TDI, MDI, HDI, IPDI） and chain extender 1,4-butanediol, in which different soft and hard segments are used to adjust their transition temperatures and mechanical properties. Poly（lactide-co-caprolactone）copolymer diols（co-PLAols） instead of PLA diols as the soft segment improved the thermal stability and mechanical properties of the synthesized bio-PUs. Among them, MDI-based bio-PUs have the highest T_g（43.8 °C）, tensile strength（23.5 MPa） and modulus（380.8 MPa）, while HDI-based bio-PUs have the lowest T_g（21.4 °C） and highest elongation at break（580%）. Especially, the bio-PUs synthesized from co-PLAols and MDI demonstrate better mechanical properties,closed to petroleum-based commodities. Furthermore, the obtained bio-PUs display good shape memory properties at body temperature and cytocompatibility. Therefore, these bio-PUs are promising for applications in biomedical fields.

Insulating materials for realising carbon neutrality:Opportunities,remaining issues and challenges

The 2050 carbon-neutral vision spawns a novel energy structure revolution,and the construction of the future energy structure is based on equipment innovation.Insulating material,as the core of electrical power equipment and electrified transportation asset,faces unprecedented challenges and opportunities.The goal of carbon neutral and the urgent need for innovation in electric power equipment and electrification assets are first discussed.The engineering challenges constrained by the insulation system in future electric power equipment/devices and electrified transportation assets are investigated.Insulating materials,including intelligent insulating material,high thermal conductivity insulating material,high energy storage density insulating material,extreme environment resistant insulating material,and environmental-friendly insulating material,are cat-egorised with their scientific issues,opportunities and challenges under the goal of carbon neutrality being discussed.In the context of carbon neutrality,not only improves the understanding of the insulation problems from a macro level,that is,electrical power equipment and electrified transportation asset,but also offers opportunities,remaining issues and challenges from the insulating material level.It is hoped that this paper en-visions the challenges regarding design and reliability of insulations in electrical equipment and electric vehicles in the context of policies towards carbon neutrality rules.The authors also hope that this paper can be helpful in future development and research of novel insulating materials,which promote the realisation of the carbon-neutral vision.

An L-band HTS duplexer with improved performance

An L-band HTS duplexer with improved performance for communication applications has been developed.This is an improved version of the duplexer previously developed by our group.The duplexer was composed of a T-junction and two channels.Each channel has a 10-pole quasi-elliptic function bandpass HTS filter with a bandwidth of 27 MHz,and center frequencies at 1200 MHz and 1260 MHz.To achieve higher performance,especially a good balance between selectivity and flat group delay,the two pairs of transmission zeros from the two filters were reassigned so that one pair is used for high selectivity and the other for flat group delay.To reduce the influence of parasitical coupling,new coupling structures were developed in the simulation process.The duplexer was fabricated on a 2 inch diameter,0.5 mm thick LaAlO3 wafer with a double-sided YBCO film.The measured results showed a very high performance:a mid-band insertion loss of 0.2 dB,a return loss better than-14 dB,a shape factor better than 1.4:1,an out-of-band rejection of better than 70 dB in a wide frequency range up to 3 GHz and excellent isolation(higher than 80 dB) between the two channels.In addition,the frequency band 5 ns group delay variation is over 10.5 MHz(38.7% of 1 dB bandwidth).

Early changes to the extracellular space in the hippocampus under simulated microgravity conditions

The smooth transportation of substances through the brain extracellular space(ECS)is crucial to maintaining brain function;however,the way this occurs under simulated microgravity remains unclear.In this study,tracer-based magnetic resonance imaging(MRI)and DECS-mapping techniques were used to image the drainage of brain interstitial fluid(ISF)from the ECS of the hippocampus in a tail-suspended hindlimb-unloading rat model at day 3(HU-3)and 7(HU-7).The results indicated that drainage of the ISF was accelerated in the HU-3 group but slowed markedly in the HU-7 group.The tortuosity of the ECS decreased in the HU-3 group but increased in the HU-7 group,while the volume fraction of the ECS increased in both groups.The diffusion rate within the ECS increased in the HU-3 group and decreased in the HU-7 group.The alterations to ISF drainage and diffusion in the ECS were recoverable in the HU-3 group,but neither parameter was restored in the HU-7 group.Our findings suggest that early changes to the hippocampal ECS and ISF drainage under simulated microgravity can be detected by tracer-based MRI,providing a new perspective for studying microgravity-induced nano-scale structure abnormities and developing neuroprotective approaches involving the brain ECS.