Ti基块体非晶合金在酸性溶液中的腐蚀行为

研究Ti_(34.3)Zr_(31.5)Cu_(5)Ni_(5.5)Be_(23.7)块体非晶合金在不同浓度HCl和H_(2)SO_(4)溶液中的腐蚀行为。电化学测试与扫描电子显微镜分析发现,在极化过程中,Cl^(-)离子在HCl溶液中引发点蚀损伤,点蚀电位随溶液浓度的增大而降低,被腐蚀表面的损伤程度则与溶液浓度呈正相关。在H_(2)SO_(4)溶液中材料表面形成钝化膜,表现出良好的耐蚀性。X射线光电子能谱分析发现,随着HCl溶液浓度的增加,钝化膜的稳定性降低。通过浸泡实验得到4种材料的腐蚀速率。结果显示,Ti_(34.3)Zr_(31.5)Cu_(5)Ni_(5.5)Be_(23.7)块体非晶合金在HCl溶液中的耐腐蚀性能最好,其腐蚀速率为7.22×10^(-3) mm/a,约为316L不锈钢腐蚀速率的1/1294。

我国高校教师数字技能研究图景、趋势与展望

2022年,教育部发布《教师数字素养》教育行业标准,在政策层面主动引领,为提升高校教师数字技能指明方向。为深入探索我国高校教师数字技能研究领域的整体概况、前沿热点和未来趋势,运用文献计量学方法,借助CiteSpace软件对中国知网数据库中的CSSCI来源期刊论文进行了可视化分析。结果表明:近年来高校教师数字技能的研究热度有所上升,但研究学者和机构间的学术交流与合作仍需加强;高校教师数字技能的构成要素、影响因素、推进路径及其与教学改革的联系是关注焦点;教师数字技能测评框架明晰了高校教师未来发展方向与目标,更加强调以人为本,关注高校教师和学生的可持续发展;数字素养向数字技能的研究转变已成为重要趋势,高校教师数字技能发展提升策略与推进路径成为研究发展的主要方向。分析结果可以为我国高校教师数字技能研究提供一定参考和镜鉴,未来应深化团体合作、推进研究落地、完善评估保障、坚持问题导向、助力教师成长,通过理论与实践的双重创新,推动我国高校教师数字技能研究领域的持续发展。

High-Efficiency Photo-Induced Charge Transfer for SERS Sensing in N-Doped 3D-Graphene on Si Heterojunction

Nitrogen-doped three-dimensional graphene(N-doped 3D-graphene)is a graphene derivative with excellent adsorption capacity,large specific surface area,high porosity,and optoelectronic properties.Herein,N-doped 3D-graphene/Si heterojunctions were grown in situ directly on silicon(Si)substrates via plasma-assisted chemical vapor deposition(PACVD),which is promising for surface-enhanced Raman scattering(SERS)substrates candidates.Combined analyses of theoretical simulation,incorporating N atoms in 3D-graphene are beneficial to increase the electronic state density of the system and enhance the charge transfer between the substrate and the target molecules.The enhancement of the optical and electric fields benefits from the stronger light-matter interaction improved by the natural nano-resonator structure of N-doped 3D-graphene.The as-prepared SERS substrates based on N-doped 3D-graphene/Si heterojunctions achieve ultra-low detection for various molecules:10^(-8)M for methylene blue(MB)and 10^(-9)M for crystal violet(CRV)with rhodamine(R6G)of 10^(10)M.In practical detected,10^(-8)M thiram was precisely detected in apple peel extract.The results indicate that N-doped 3D-graphene/Si heterojunctions based-SERS substrates have promising applications in low-concentration molecular detection and food safety.

How to promote cooperative innovation in environmentally friendly technology:a case of agricultural biotechnology in China

This study explored the factors influencing cooperative innovation in environmentally friendly agricultural biotechnology in China.First,we constructed an evolutionary game model comprising the factors of net income of cooperative innovation,net income of independent innovation,market constraints,and government subsidies.Using MATLAB simulation,we assigned different values to the aforementioned variables to explore the evolutionary trend of innovators’willingness to cooperate.Results showed that when the values of net income of cooperative innovation,net income of independent innovation,market constraints,and government subsidies exceeded the threshold,innovators’willingness to cooperate was significantly enhanced.Furthermore,the proportion of innovators who cooperated with others gradually increased to 100%;otherwise,it gradually decreased to 0%.Comparing the simulation curve with the real evolution curve of cooperative innovation in agricultural biotechnology in China,we found that the gradual decline in the willingness to cooperate could be due to insufficient subsidies for cooperative innovation,low income from cooperative innovation,weak profitability of innovators,and weak market constraints.

Thirty-year trends of anxiety disorders among adolescents based on the 2019 Global Burden of Disease Study

Background Anxiety disorders are the most common psychiatric problems,affecting approximately 1 in 12 children and 1 in 4 adolescents.Understanding the incidence,burden and correlated risks of anxiety disorders among children and adolescents can help identify areas of success,stagnation and emerging threats,thereby facilitating effective improvement strategies.Aims To estimate the incidence and burden trends of anxiety disorders in children and adolescents from 1990 to 2019 in 204 countries and compare the incidence and disease burden in different countries.To examine the association between anxiety disorders and social indicators(healthcare access and quality of life).Methods Data were obtained from the Global Burden of Disease Study 2019.The age-standardised incidence rates(ASIRs)and disability-adjusted life years(DALYs)were reported to assess the burden of anxiety disorders,and the estimated annual percentage change was calculated to quantify the temporal trends.Pearson’s correlation was used to investigate country-level risk factors for incidence and DALYs.Results Globally,there were 932 million incident cases of anxiety disorders in children and adolescents,739.29 per 100000 ASIRs and 380.62 million DALYs in 2019.From 1990 to 2019,the estimated annual percentage change of incidence of anxiety disorders decreased by 2.2%.Significant variations were observed in the age-standardised burden rate and the changing trend of anxiety disorders among countries.Portugal reported the highest ASIR of anxiety disorders,while Mexico had the largest increase rate of ASIR.In 2019,Portugal reported the highest number of DALYs(1001.71 million),and India(212.09 million)reported the lowest number of DALYs.The burden of anxiety disorders was positively correlated with the average number of psychiatrists,psychologists and nurses in the mental health sector(per 100000),and quality of life and the correlation coefficients were 0.58,0.67,0.43 and 0.53,respectively.Conclusions The incidence and global burden of anxiety disorders in adolescents have continued to decrease over the past 30 years.However,the incidence and disease burden in developed countries are still increasing steadily.Policymakers should design and implement mental health strategies for adolescents based on their specific developmental status,as well as the cultural and regional characteristics of each country.

Rural Domestic Sewage Treatment Model: Case Study Based on Dongying Section of the Yellow River Basin

The 20th National Congress of the Communist Party of China proposed to promote the improvement of urban and rural living environment and build livable and workable villages and beautiful villages. The development and challenges of rural domestic sewage treatment coexist. Based on the field investigation of 15 administrative villages in 3 districts and counties of Dongying City, there is a big gap between the development status of rural domestic sewage treatment and expectations. Investigate rural domestic sewage treatment cases in-depth, and condense four modes of primitive, developmental, mature and advanced in a variety of different rural domestic sewage treatment models for discussion, among which, the village sewage treatment work under the mature mode has achieved remarkable results, and is at the forefront of the current rural domestic sewage treatment. Through the multi-case analysis method, the practical dilemma of sewage treatment in different models of villages is summarized, and the feasible improvement path is explored, which contributes to the ecological protection and high-quality development of Dongying and the Yellow River Basin.

Supplementing the early diet of broilers with soy protein concentrate can improve intestinal development and enhance short-chain fatty acid-producing microbes and short-chain fatty acids,especially butyric acid

Background:Research on nutrition in early-life commonly focuses on the maturation of the intestine because the intestinal system is crucial for ensuring continued growth.To explore the importance of early nutrition regulation in animals,soy protein concentrate(SPC)was added to the early diet of broilers to investigate its effects on amino acid digestibility,intestinal development,especially intestinal microorganisms,and broiler metabolites.A total of 192 oneday-old Arbor Acres(AA)male broilers were randomly assigned to two experimental treatments with 8 replicates of 12 birds.The control group was fed a basal diet(control),and the treatment group was fed a basal diet supplemented with 12%SPC(SPC12)during the first 10 d(starter phase).From d 11 to 21(grower phase)and d 22 to 42(finisher phase),a basal diet was fed to both treatment groups.Results:SPC reduced the pH value and acid-binding capacity of the starter diet(P<0.05,d 10);SPC in the early diet enhanced the gizzard weight(P<0.05,d 10 and d 42)and the ileum weight(P<0.05,d 10)and decreased the weight and length of the jejunum(P<0.05,d 10)and the relative length of the duodenum and jejunum(P<0.05,d 10).At the same time,SPC enhanced villus height(P<0.05,d 10)and muscle thickness in the jejunum and ileum(P<0.05,d 10)and increased the number of goblet cells in the duodenum(P<0.05,d 10).Meanwhile,SPC increased the Chao1 index and the ACE index(P<0.05,d 10)and altered the composition of caecal microflora at d 10.SPC also increased the relative abundance of Alistipes,Anaerotruncus,Erysipelatoclostridium,Intestinimonas and Flavonifractor bacteria(P<0.05,d 10).At the same time,the concentrations of caecal butyric acid and total short-chain fatty acids(SCFAs)were also increased in the SPC12 group(P<0.05,d 10).Conclusions:In summary,the results showed that supplementing the starter diet of broilers with SPC has a significant effect on the early development of the intestine and the microflora.

Safety and Efficacy of Endovascular Aortic Repair for Abdominal Aortic Aneurysms with a Hostile Neck Anatomy

Objective This study aimed to investigate the safety and efficacy of endovascular aortic repair(EVAR)for the treatment of an abdominal aortic aneurysm(AAA)with a hostile neck anatomy(HNA).Methods From January 1,2015 to December 31,2019,a total of 259 patients diagnosed with an AAA who underwent EVAR were recruited into this study.Based on the morphological characteristics of the proximal neck anatomy,the patients were divided into the HNA group and the friendly neck anatomy(FNA)group.The patients were followed up for up to 4 years.Results The average follow-up time was 1056.1±535.5 days.Type I endoleak occurred in 4 patients in the HNA group,and 2 patients in the FNA group.Neither death nor intraoperative switch to open repair occurred in either group.The time of the operation was significantly longer in the HNA group(FNA vs.HNA,99.2±51.1 min vs.117.5±63.8 min,P=0.011).There were no significant differences in short-term clinical success rate(P=0.228)or midterm clinical success rate(P=0.889)between the two groups.The overall mortality rate was 10.4%,and Kaplan-Meier survival analysis indicated that the two groups had similar cumulative survival rates at the end of the follow-up period(P=0.889).Conclusion EVAR was feasible and safe in patients with an AAA with a proximal HNA.The early and midterm results were promising;however,further studies are needed to verify the long-term effectiveness of EVAR.

Natural Graphene Plasmonic Nano-Resonators for Highly Active Surface-Enhanced Raman Scattering Platforms

Highly sensitive and uniform three-dimensional(3D)hybrid heterogeneous structures for use in surface-enhanced Raman scattering(SERS)experiments were fabricated by sequentially decorating high-quality,ultra-clean,graphene quantum dots(GQDs)and Ag nanoparticles(Ag-NPs)onto 3D-graphene.Finite-difference time-domain calculations and scanning Kelvin probe microscopy were used to verify that the Ag-NPs/GQDs/3D-graphene system facilitates substantial electromagnetic enhancement(due to the occurrence of two kinds of"gaps"between the Ag-NPs that form 3D"hot spots")and additional chemical enhancement(in detecting someπ-conjugated molecules).The SERS mechanism was explored in further detail via experimental analysis and confirmed by performing theoretical calculations.The large surface area of the 3D substrate(due to the large specific surface areas of the GQDs and 3D-graphene)results in a better enrichment effect which helps produce lower detection limits.In particular,the detection limits obtained using the Ag-NPs/GQDs/3D-graphene platform can reach 10^(-11)M for rhodamine 6G,10^(-10)M for methylene blue and dopamine,and 10^(-7)M for tetramethylthiuram disulfide and methyl parathion in apple juice(these are superior to most of the results reported using graphene-based SERS substrates).In summary,the 3D-platform Ag-NPs/GQDs/3D-graphene/Si shows outstanding SERS performance.It therefore has excellent application prospects in biochemical molecular detection and food safety monitoring.

Gatemon Qubit Based on a Thin InAs-Al Hybrid Nanowire

We study a gate-tunable superconducting qubit(gatemon) based on a thin InAs-Al hybrid nanowire.Using a gate voltage to control its Josephson energy,the gatemon can reach the strong coupling regime to a microwave cavity.In the dispersive regime,we extract the energy relaxation time T_(1)~0.56 μs and the dephasing time T_(2)^(*)~0.38 μs.Since thin In As-Al nanowires can have fewer or single sub-band occupation and recent transport experiment shows the existence of nearly quantized zero-bias conductance peaks,our result holds relevancy for detecting Majorana zero modes in thin InAs-Al nanowires using circuit quantum electrodynamics.

Uniform Hölder Bounds for Competition Systems with Strong Interaction on a Subdomain

We prove the uniform Hölder bounds of solutions to a singularly perturbed elliptic system arising in competing models in population dynamics. In this system, two species compete to some extent throughout the whole domain but compete strongly on a subdomain. The proof relies upon the blow up technique and the monotonicity formula by Alt, Caffarelli and Friedman.

A Review on Water-Saving Agriculture in Europe

This paper aims to analyze the research on the current situation of water-saving agriculture development in Europe. Water-saving agriculture in Europe started early, governments and farmers in various countries have a strong awareness of water-saving in agriculture and have achieved certain results. Due to the global spread of the COVID-19 pandemic, the lack of up-to-date field research, the complexity of various agricultural disciplines and categories, and the lack of information sharing, the current cognition of recent progress in the development of water-saving agriculture in Europe is not comprehensive enough. This paper selects four representative European countries: Spain, Germany, Italy, and Denmark as the research objects. Based on the existing research of Chinese and Western scholars, this paper analyzes and studies the current situation of water-saving agriculture in Europe. It has far-reaching significance for other countries in the world to have further development in water-saving agriculture and to protect water resources.

血浆SEPT9基因甲基化监测结直肠癌术后复发转移的应用价值

目的:探讨血浆SEPT 9基因甲基化(mSEPT9)在结直肠癌根治术后复发监测中的应用价值。方法:回顾性分析2013年2月至2015年1月聊城市人民医院确诊并行根治性手术的结直肠癌患者214例,收集术前及随访3年中的外周血样本,应用荧光探针PCR方法检测血浆mSEPT9状态,化学发光法检测血清CEA水平,评价血浆mSEPT9用于结直肠癌手术疗效评价价值,并评估血浆mSEPT9和血清CEA单独或两者联合检测对结直肠癌复发转移的诊断效力。结果:结直肠癌患者术前血浆mSEPT9检测阳性率为70.1%,血浆mSEPT9与临床分期相关(P=0.027),与年龄和性别不相关。结直肠癌根治术后,血浆mSEPT9阳性率为8.4%,与术前相比差异具有统计学意义(P<0.001)。64例结直肠癌复发转移患者mSEPT9阳性率为78.1%,CEA阳性率为40.6%,差异具有统计学意义(P<0.001)。血浆mSEPT9联合血清CEA检测能够提高结直肠癌复发转移的阳性率(84.4%vs.78.1%,P=0.016)。结论:血浆mSEPT9可作为结直肠癌根治术疗效评价及术后随访监测的分子标志物。

Clinicopathological features and prognostic factors associated with gastroenteropancreatic mixed neuroendocrine non-neuroendocrine neoplasms in Chinese patients

BACKGROUND The incidence of mixed neuroendocrine-non-neuroendocrine neoplasms(MiNEN)is low.To improve our understanding of this rare tumor type and optimally guide clinical treatment,associated risk factors,clinical manifestations,and prognosis must be explored.AIM To identify risk factors that influence the prognosis of patients with gastroenteropancreatic MiNEN(GEP-MiNEN).METHODS We retrospectively analyzed the clinical data of 46 patients who were diagnosed with GEP-MiNEN at the First Affiliated Hospital of Bengbu Medical College(Anhui,China)between January 2013 and December 2017.Risk factors influencing the prognosis of the patients were assessed using Kaplan-Meier curves and cox regression models.We compared the results with 55 randomly selected patients with gastroenteropancreatic GEP neuroendocrine tumors,47 with neuroendocrine carcinomas(NEC),and 58 with poorly differentiated adenocarcinoma.RESULTS Among the 46 patients with GEP-MiNEN,thirty-five had gastric tumors,nine had intestinal tumors(four in the small intestine and five in the colon and rectum),and two had pancreatic tumors.The median age of the patients was 66(41-84)years,and the male-to-female ratio was 2.83.Thirty-three(71.7%)patients had clinical stage III and IV cancers.Distant metastasis occurred in 14 patients,of which 13 had metastasis to the liver.The follow-up period was 11-72 mo,and the median overall survival was 30 mo.Ki-67 index≥50%,high proportion of NEC,lymph node involvement,distant metastasis,and higher clinical stage were independent risk factors affecting the prognosis of patients with GEP-MiNEN.The median overall survival was shorter for patients with NEC than for those with MiNEN(14 mo vs 30 mo,P=0.001),but did not significantly differ from those with poorly differentiated adenocarcinoma and MiNEN(30 mo vs 18 mo,P=0.453).CONCLUSION A poor prognosis is associated with rare,aggressive GEP-MiNEN.Ki-67 index,tumor composition,lymph node involvement,distant metastasis,and clinical stage are important factors for patient prognosis.

窒息新生儿血NGAL、CysC和尿微量蛋白的水平变化及临床意义

目的探讨窒息新生儿尿α1微球蛋白(α1-m)、β2微球蛋白(β2-m)、白蛋白(Alb)、免疫球蛋白G(IgG)、转铁蛋白(TRF)、血中性粒细胞明胶酶相关脂质运载蛋白(NGAL)及半胱氨酸蛋白酶抑制剂(CysC)水平的变化及对新生儿早期肾损伤的诊断价值。方法取187例窒息新生儿(轻度窒息90例,重度窒息97例)及95例同期入院的健康新生儿出生后24 h内取尿液作α1-m、β2-m、Alb、Ig G及TRF检测;取12 h内静脉血检测NGAL、CysC、BUN及血肌酐(Scr),并进行比较分析。结果轻、重度窒息组α1-m、β2-m、Alb、IgG、TRF、NGAL及CysC含量均较对照组升高(P<0.05),重度窒息组α1-m、β2-m、Alb、IgG、TRF、NGAL及CysC异常率高于轻度窒息组(P<0.05)。结论α1-m、β2-m、Alb、IgG、TRF、NGAL及CysC含量是窒息新生儿早期肾功能损伤监测的有效指标。而传统指标Scr及BUN在窒息新生儿早期肾损伤的诊断中优越性不明显。

Characterization of Aroma-Active Components and Antioxidant Activity Analysis of E-jiao(Colla CoriiAsini)from Different Geographical Origins

E-jiao(Colla Corii Asini,CCA)has been widely used as a healthy food and Chinese medicine.Although authentic CCA is characterized by its typical sweet and neutral fragrance,its aroma components have been rarely investigated.This work investigated the aroma-active components and antioxidant activity of 19 CCAs from different geographical origins.CCA extracts obtained by simultaneous distillation and extraction were analyzed by gas chromatography-mass spectrometry(GC-MS),gas chromatography-olfactometry(GC-O)and sensory analysis.The antioxidant activity of CCAs was determined by ABTS and DPPH assays.A total of 65 volatile compounds were identified and quantified by GC-MS and 23 aroma-active compounds were identified by GC-O and aroma extract dilution analysis.The most powerful aroma-active compounds were identified based on the flavor dilution factor and their contents were compared among the 19 CCAs.Principal component analysis of the 23 aroma-active components showed 3 significant clusters.Canonical correlation analysis between antioxidant assays and the 23 aroma-active compounds indicates strong correlation(r=0.9776,p=0.0281).Analysis of aroma-active components shows potential for quality evaluation and discrimination of CCAs from different geographical origins.

Hepatic perivascular epithelioid cell tumor:Clinicopathological analysis of 26 cases with emphasis on disease management and prognosis

BACKGROUND Perivascular epithelioid cell tumor(PEComa)is an uncommon tumor of mesenchymal origin.Cases of PEComa in the liver are extremely rare.AIM To analyze the clinicopathological features and treatment of hepatic PEComa and to evaluate the prognosis after different treatments.METHODS Clinical and pathological data of 26 patients with hepatic PEComa were collected.All cases were analyzed by immunohistochemistry and clinical follow-up.RESULTS This study included 17 females and 9 males,with a median age of 50 years.Lesions were located in the left hepatic lobe in 13 cases,in the right lobe in 11,and in the caudate lobe in 2.The median tumor diameter was 6.5 cm.Light microscopy revealed that the tumor cells were mainly composed of epithelioid cells.The cytoplasm contained heterogeneous eosinophilic granules.There were thick-walled blood vessels,around which tumor cells were radially arranged.Immunohistochemical analysis of pigment-derived and myogenic markers in PEComas revealed that 25 cases were HMB45(+),23 were Melan-A(+),and 22 SMA(+).TFE3 and Desmin were negative in all cases.All the fluorescence in situ hybridization samples were negative for TFE3 gene break-apart probe.Tumor tissues were collected by extended hepatic lobe resection or simple hepatic tumor resection as the main treatments.Median follow-up was 62.5 mo.None of the patients had metastasis or recurrence,and there were no deaths due to the disease.CONCLUSION Hepatic PEComa highly expresses melanin and smooth muscle markers,and generally exhibits an inert biological behavior.The prognosis after extended hepatic lobe resection and simple hepatic tumor resection is semblable.

真核起始因子3e亚基与原发性肝细胞癌的发生与发展正相关

背景真核起始因子3(eukaryotic initiation factor 3,eIF3)是哺乳动物细胞中最复杂的翻译起始因子,真核起始因子3e亚基(eukaryotic initiation factor 3e subunit,eIF3e)是eIF313个亚基中的一个,其表达水平的失调与癌症的发生和发展密切相关.然而,eIF3e在不同类型的恶性肿瘤中的报道相互矛盾.迄今为止,eIF3e在原发性肝细胞癌(primary hepatocellular carcinoma,HCC)中的作用不明.目的研究eIF3e在HCC发生和发展中的作用.方法从临床上随机获取5例HCC病人手术后的新鲜肝癌组织及癌旁组织标本,用qRT-PCR和Western Blot分别定量检测肝癌组织和癌旁组织内eIF3e的mRNA转录水平和蛋白表达水平.通过转染eIF3e过表达质粒或eIF3e干扰质粒进入HepG2,用qRT-PCR及Western Blot分别定量检测细胞内eIF3e转录和翻译表达水平,证实eIF3E过表达上调和干扰后的下调.用Kit-8细胞计数法(Cell Counting Kit-8,CCK-8)评价细胞增殖行为;用划痕实验观察细胞迁移行为;用流氏分析法调查细胞凋亡行为;运用裸鼠成瘤实验评价eIF3e对肿瘤生长的影响.结果和癌旁组织比较,发现肝癌组织中eIF3e上调.细胞实验证实,肝癌细胞系HepG2及Huh7中eIF3e mRNA转录水平均高于正常肝细胞系HL7702.过表达质粒和干扰质粒分别瞬时转染HepG2,发现eIF3e上调后增强了HepG2增殖和迁移行为,但对细胞凋亡无影响;而eIF3e下调后,减弱了HepG2增殖和迁移行为,促进凋亡;裸鼠实验结果证实eIF3e促进肿瘤生长.结论eIF3e的过表达与原发性肝细胞癌的发生和发展正相关,有潜力成为HCC治疗新靶点.

Number Entities Recognition in Multiple Rounds of Dialogue Systems

As a representative technique in natural language processing(NLP),named entity recognition is used in many tasks,such as dialogue systems,machine translation and information extraction.In dialogue systems,there is a common case for named entity recognition,where a lot of entities are composed of numbers,and are segmented to be located in different places.For example,in multiple rounds of dialogue systems,a phone number is likely to be divided into several parts,because the phone number is usually long and is emphasized.In this paper,the entity consisting of numbers is named as number entity.The discontinuous positions of number entities result from many reasons.We find two reasons from real-world dialogue systems.The first reason is the repetitive confirmation of different components of a number entity,and the second reason is the interception of mood words.The extraction of number entities is quite useful in many tasks,such as user information completion and service requests correction.However,the existing entity extraction methods cannot extract entities consisting of discontinuous entity blocks.To address these problems,in this paper,we propose a comprehensive method for number entity recognition,which is capable of extracting number entities in multiple rounds of dialogues systems.We conduct extensive experiments on a real-world dataset,and the experimental results demonstrate the high performance of our method.

In Situ Epitaxy of Pure Phase Ultra-Thin InAs-Al Nanowires for Quantum Devices

We demonstrate the in situ growth of ultra-thin InA s nanowires with an epitaxial Al film by molecular-beam epitaxy.Our InAs nanowire diameter(~30 nm)is much thinner than before(~100 nm).The ultra-thin InAs nanowires are pure phase crystals for various different growth directions.Transmission electron microscopy confirms an atomically abrupt and uniform interface between the Al shell and the InAs wire.Quantum transport study on these devices resolves a hard induced superconducting gap and 2 e-periodic Coulomb blockade at zero magnetic field,a necessary step for future Majorana experiments.By reducing wire diameter,our work presents a promising route for reaching fewer sub-band regime in Major ana nanowire devices.