Efficacy of fexuprazan compared with rebamipide in Korean patients with gastritis:A matching-adjusted indirect comparison

BACKGROUND Gastritis is one of the most frequently diagnosed diseases requiring medical treatment in South Korea.Fexuprazan,a novel potassium-competitive acid blocker,has been approved for treating gastritis and erosive esophagitis.Meanwhile,rebamipide is the most commonly used mucoprotective agent for acute and chronic gastritis in real-world settings in South Korea.However,there have been no studies comparing the efficacy of these two drugs yet.AIM To compare the efficacy of fexuprazan with that of rebamipide for acute and chronic gastritis.METHODS This was a matching-adjusted indirect comparison.Individual patient data from a phase III study of fexuprazan(10 mg BID)were compared with cumulative data from two matching studies of rebamipide(100 mg TID).Erosion improvement and healing rates were compared between two weeks of fexurapan,two weeks of rebamipide,and four weeks of rebamipide.The two main outcome variables were presented as percentages,and the risk differences(RD)and 95%confidence intervals(CI)were calculated for the relative treatment effects.RESULTS In the primary analysis,the erosion improvement and healing rates after a twoweek treatment with fexuprazan were 64.5%and 53.2%,respectively,while a twoweek treatment with rebamipide resulted in erosion improvement and healing rates of 43.6%(RD:21.0%;95%CI:9.6-32.3;P<0.01)and 35.6%(RD:17.6%;95%CI:6.1-29.2;P=0.003),respectively.In the additional analysis,the erosion improvement and healing rates for the two-week fexuprazan treatment(64.2%and 51.2%,respectively)were similar to those obtained during a four-week treatment with rebamipide(60.6%;RD:3.6%;95%CI:-9.8,17.0;P=0.600 and 53.5%;RD:-2.3%;95%CI:-16.1,11.5;P=0.744,respectively).CONCLUSION The two-week fexuprazan treatment was superior to the two-week rebamipide treatment and similar to the fourweek rebamipide treatment for patients with gastritis.

Accuracy comparison and improvement for state of health estimation of lithium-ion battery based on random partial recharges and feature engineering

State of health(SOH)estimation of e-mobilities operated in real and dynamic conditions is essential and challenging.Most of existing estimations are based on a fixed constant current charging and discharging aging profiles,which overlooked the fact that the charging and discharging profiles are random and not complete in real application.This work investigates the influence of feature engineering on the accuracy of different machine learning(ML)-based SOH estimations acting on different recharging sub-profiles where a realistic battery mission profile is considered.Fifteen features were extracted from the battery partial recharging profiles,considering different factors such as starting voltage values,charge amount,and charging sliding windows.Then,features were selected based on a feature selection pipeline consisting of filtering and supervised ML-based subset selection.Multiple linear regression(MLR),Gaussian process regression(GPR),and support vector regression(SVR)were applied to estimate SOH,and root mean square error(RMSE)was used to evaluate and compare the estimation performance.The results showed that the feature selection pipeline can improve SOH estimation accuracy by 55.05%,2.57%,and 2.82%for MLR,GPR and SVR respectively.It was demonstrated that the estimation based on partial charging profiles with lower starting voltage,large charge,and large sliding window size is more likely to achieve higher accuracy.This work hopes to give some insights into the supervised ML-based feature engineering acting on random partial recharges on SOH estimation performance and tries to fill the gap of effective SOH estimation between theoretical study and real dynamic application.

Efficacy comparison of multipoint and single point scanning panretinal laser photocoagulation in non-proliferative diabetic retinopathy treatment

BACKGROUND Non-proliferative diabetic retinopathy(NPDR)poses a significant challenge in diabetes management due to its microvascular changes in the retina.Laser photocoagulation,a conventional therapy,aims to mitigate the risk of progressing to proliferative diabetic retinopathy(PDR).AIM To compare the efficacy and safety of multi-spot vs single-spot scanning panretinal laser photocoagulation in NPDR patients.METHODS Forty-nine NPDR patients(86 eyes)treated between September 2020 and July 2022 were included.They were randomly allocated into single-spot(n=23,40 eyes)and multi-spot(n=26,46 eyes)groups.Treatment outcomes,including bestcorrected visual acuity(BCVA),central macular thickness(CMT),and mean threshold sensitivity,were assessed at predetermined intervals over 12 months.Adverse reactions were also recorded.RESULTS Energy levels did not significantly differ between groups(P>0.05),but the multi-spot group exhibited lower energy density(P<0.05).BCVA and CMT improvements were noted in the multi-spot group at one-month posttreatment(P<0.05).Adverse reaction incidence was similar between groups(P>0.05).CONCLUSION While energy intensity and safety were comparable between modalities,multi-spot scanning demonstrated lower energy density and showed superior short-term improvements in BCVA and CMT for NPDR patients,with reduced laser-induced damage.

Global Research Progress on Municipal Waste and Future Prospect Based on the Cross-national Comparisons

Due to the acceleration of urbanization,the municipal waste(MW)problem has transformed into a global challenge for urb-an sustainability.To elucidate historical trends,current focal points,and future directions in MW research,we conducted a bibliometric analysis and employed knowledge graph visualization to scrutinize a total of 34212 articles,which were published between 1991 and 2021 in the Web of Science(WoS)core database.The results indicated that current major research themes encompass waste classifica-tion and recycling,waste management and public behavior,waste disposal methods and technologies,as well as environmental impact and evaluation.There has been a shift in the research focus from the environmental impacts of waste incineration to sustainable manage-ment related issues.A comparison of research from six typical countries revealed the differences in research priorities and techniques advantages.Scholars from the USA and Britain initiated MW research earlier than other countries and investigated management issues in depth,such as public behavior and willingness to pay.Meanwhile,Japanese,German,and Swedish scholars conducted extensive studies on advanced waste treatment technologies,such as disposal and recycling,risk assessment,and waste-to-energy techniques.Chinese scholars placed particular emphasis on end-of-pipe treatments and their associated environmental impacts.Hotspots and poten-tial future frontiers were identified by burst detection analysis.Keywords with high value of burst index(BI)worldwide are food waste and circular economy.Chinese scholars have put great efforts on waste environmental impact and its recycling technologies,while we’re expecting to further investigating vulnerable population.Furthermore,this study contributes to bridging the regional gap of scientific research among different countries and fostering international collaboration.

Comparison and Selection of Water Restoration Techniques for Artificial Landscape Lakes in Nantong City

As an important part of urban infrastructure,urban water system is of great and far-reaching significance for ensuring urban flood control and waterlogging safety,protecting ecological environment and building livable homes.Taking the urban water system of Nantong as an example,Nantong Water Resources Bureau issued R evision of Nantong Urban Water System Planning in 2017,and put forward the construction of the"two circles,eight lakes and nine veins"water system layout,giving new vitality to the urban water system.In view of problems existing in newly excavated artificial landscape lakes,such as fragile water ecosystem,strong eutrophication trend,poor environmental sensory effect and unsatisfactory water landscape effect,it is urgent to study the in-situ water ecological restoration technique of"algae-controlling zooplankton+submerged plant community"to build a"grass-type clear water"ecosystem for artificial landscape lakes,so as to improve the water sensory index and self-purification ability and finally realize the double improvement of"sensory effect and water quality"of artificial landscape lakes.

Direct Pointwise Comparison of FE Predictions to StereoDIC Measurements:Developments and Validation Using Double Edge-Notched Tensile Specimen

To compare finite element analysis(FEA)predictions and stereovision digital image correlation(StereoDIC)strain measurements at the same spatial positions throughout a region of interest,a field comparison procedure is developed.The procedure includes(a)conversion of the finite element data into a triangular mesh,(b)selection of a common coordinate system,(c)determination of the rigid body transformation to place both measurements and FEA data in the same system and(d)interpolation of the FEA nodal information to the same spatial locations as the StereoDIC measurements using barycentric coordinates.For an aluminum Al-6061 double edge notched tensile specimen,FEA results are obtained using both the von Mises isotropic yield criterion and Hill’s quadratic anisotropic yield criterion,with the unknown Hill model parameters determined using full-field specimen strain measurements for the nominally plane stress specimen.Using Hill’s quadratic anisotropic yield criterion,the point-by-point comparison of experimentally based full-field strains and stresses to finite element predictions are shown to be in excellent agreement,confirming the effectiveness of the field comparison process.

平“语”近人中课程思政元素comparison的应用及分析

文章的研究目的是理解平“语”近人中comparison(比喻)的用法,平“语”近人中课程思政的内容和其背后的真实含义具有重要的教育意义。文章以话语中课程思政元素的comparison主要例子作为研究对象,来探讨和研究平“语”近人话语中的关于comparison的应用并且加以分析。

Multiomics comparison among populations of three plant sources of Amomi Fructus

Amomi Fructus(Sharen,AF)is a traditional Chinese medicine(TCM)from three source species(or varieties),including Wurfbainia villosa var.villosa(WVV),W.villosa var.xanthioides(WVX),or W.longiligularis(WL).Among them,WVV has been transplanted from its top-geoherb region,Guangdong,to its current main production area,Yunnan,for>50 years in China.However,the genetic and transcriptomic differentiation among multiple AF source species(or varieties)and between the origin and transplanted populations of WVV is unknown.In our study,the observed overall higher expression of terpenoid biosynthesis genes in WVV than in WVX provided possible evidence for the better pharmacological effect of WVV.We also screened six candidate borneol dehydrogenases(BDHs)that potentially catalyzed borneol into camphor in WVV and functionally verified them.Highly expressed genes at the P2 stage of WVV,Wv05G1424 and Wv05G1438,were capable of catalyzing the formation of camphor from(+)-borneol,(-)-borneol and DL-isoborneol.Moreover,the BDH genes may experience independent evolution after acquiring the ancestral copies,and the following tandem duplications might account for the abundant camphor content in WVV.Furthermore,four populations of WVV,WVX,and WL are genetically differentiated,and the gene flow from WVX to WVV in Yunnan contributed to the greater genetic diversity in the introduced population(WVV-JH)than in its top-geoherb region(WVV-YC),which showed the lowest genetic diversity and might undergo genetic degradation.In addition,terpene synthesis(TPS)and BDH genes were selected among populations of multiple AF source species(or varieties)and between the top-and non-top-geoherb regions,which might explain the difference in metabolites between these populations.Our findings provide important guidance for the conservation,genetic improvement,and industrial development of the three source species(or varieties)and for identifying top-geoherbalism with molecular markers,and proper clinical application of AF.

First acceptance testing of multiple A10 absolute gravimeters in China and analysis of the comparison results

Three A10 absolute gravimeters(AGs) were first acquired in China by the Hubei Earthquake Agency under the Belt and Road Seismic Monitoring Network Project. Although AG measuring and testing technique is not new, the purchase and simultaneous testing of 3 A10 absolute gravimeters is unprecedented in China. This study conducted the first acceptance testing of the AGs at 3 locations(the Jiufengshan Gravity Observation Station, the Global Navigation Satellite System Observation Station in Wuhan, and the Jiugongshan Observation Station in Xianning). The results were compared using a method based on expert validation, and the acceptance testing scheme was formulated by referring to the Technical Regulations for Tectonic Environment Monitoring Networks in China and Specifications for Gravimetry Control. Based on the repeatability, precision, and consistency of the measured g values, the results from each instrument were evaluated using the air pressure precision test. Comparing the instrument reference values, the final test results can identify the indicator parameters for 3 A10 AGs, the effects of the surrounding environment, and the related parameters on measurement precision. The precision of A10-059, A10-058, and A10-057 exceeded 0.78 μGal, 0.79 μGal, and 0.42 μGal, respectively.This testing scheme can be used as a reference for conducting acceptance testing of AGs in the future and obtaining absolute gravimetric measurements.

Natural gas characteristics and gas-source comparisons of the Lower Triassic Feixianguan Formation,Eastern Sichuan Basin,China

There is great controversy regarding the origin and source of natural gas in the Lower Triassic Feix-ianguan Formation in the Eastern Sichuan Basin.This seriously restricts the study of natural gas dy-namics in the Feixianguan Formation and thus hampers natural gas exploration in the region,so further study is urgently required.Using experimental tests of natural gas composition,stable isotopes,and noble gas isotopes with gas chromatography(GC)and mass spectrometry(MS)studies of source rock and reservoir asphalt saturated hydrocarbons,the natural gas geochemical characteristics,the genetic identification and a gas-source comparison of the Feixianguan Formation were studied.Then,con-strained by the thermal history,the histories of gas generation and expulsion were restored by basin simulation technology.Finally,a gas accumulation model was established for the Feixianguan Formation.The results showed that(1)the H_(2)S-rich and H2S-poor gas reservoirs of the Feixianguan Formation are distributed on the east and west sides of the Kaijiang-Liangping trough in the Eastern Sichuan Basin,respectively.The carbon and hydrogen isotope compositions of the natural gas in the gas reservoirs are generally heavy and have typical characteristics of high-maturity dry gas reservoirs.(2)The natural gas of the Feixianguan Formation is organic thermogenic gas,which is mainly oil-type gas generated by the secondary cracking of crude oil.The gas-generating parent material is mainly type II kerogen.(3)The natural gas of the Feixianguan Formation in the Eastern Sichuan Basin was mainly generated by argil-laceous source rocks of the Upper Permian Longtan Formation.(4)Natural gas accumulation occurred as follows:the paleo-structure heights were filled with crude oil in the Early Jurassic,and paleo-oil res-ervoirs were formed in the Feixianguan Formation;during the Middle-Late Jurassic,the paleo-oil res-ervoirs were cracked when the reservoir temperatures rose above 160 C,and paleo-gas reservoirs were formed.Since the end of the Late Jurassic,the paleo-gas reservoirs have been adjusted and reformed to form the present-day natural gas reservoirs.These results provide a basis for studying natural gas accumulation dynamics of the Feixianguan Formation in the Eastern Sichuan Basin.

An Effective Security Comparison Protocol in Cloud Computing

With the development of cloud computing technology,more and more data owners upload their local data to the public cloud server for storage and calculation.While this can save customers’operating costs,it also poses privacy and security challenges.Such challenges can be solved using secure multi-party computation(SMPC),but this still exposes more security issues.In cloud computing using SMPC,clients need to process their data and submit the processed data to the cloud server,which then performs the calculation and returns the results to each client.Each client and server must be honest.If there is cooperation or dishonest behavior between clients,some clients may profit from it or even disclose the private data of other clients.This paper proposes the SMPC based on a Partially-Homomorphic Encryption(PHE)scheme in which an addition homomorphic encryption algorithm with a lower computational cost is used to ensure data comparability and Zero-Knowledge Proof(ZKP)is used to limit the client’s malicious behavior.In addition,the introduction of Oblivious Transfer(OT)technology also ensures that the semi-honest cloud server knows nothing about private data,so that the cloud server of this scheme can calculate the correct data in the case of malicious participant models and safely return the calculation results to each client.Finally,the security analysis shows that the scheme not only ensures the privacy of participants,but also ensures the fairness of the comparison protocol data.

A comparison study of prevalence,awareness,treatment and control rates of hypertension and associated factors among adults in China and the United States based on national survey data

Objective:This study compared the prevalence,awareness,treatment and control of hypertension and associated factors in China and the United States(US).Methods:Adult data from nationally representative samples were derived from the Chronic Disease and Risk Factors Surveillance in 2010 and 2013 in China and the National Health and Nutrition Examination Survey in 2010 and 2013 in the US.Multivariable logistic and Poisson regression analysis were conducted to assess associations of the four outcomes with body weight status and behavioral factors.Results:Age-standardized prevalence rates of hypertension was 35.7%(95%confidence interval[CI]:35.4%to 36.1%)in 2010 and 29.8%(95%CI:29.4%to 30.2%)in 2013 in China,and 35.3%(95%CI:33.6%to 37.1%)in 2010 and 37.9%(95%CI:36.0%to 39.7%)in 2013 in the US.Among hypertensive participants,the age-standardized rates of treatment were 18.4%(95%CI:17.9%to 1&9%)in 2010 and 23.8%(95%CI:23.1%to 24.6%)in 2013 in China and 54.5%(95%CI:50.3%to 5&7%)in 2010 and 50.9%(95%CI:46.5%to 55.3%)in 2013 in the US;the age-standardized hypertension control rates were 3.2%(95%CI:3.0%to 3.5%)and 5.7%(95%CI:5.3%to 6.0%)in 2010 and 2013 in China and 50.6%(95%CI:46.2%to 55.0%)and 55.3%(95%CI:50.3%to 60.3%)in the US.Obesity was significantly associated with prevalence,awareness and control rates in both countries.Different from the US,obesity was negatively associated with hypertension control in China.Conclusion:Hypertension prevalence in China is similar to that in the US,but the control rate in China was significantly lower.Obesity was a critical risk factor for poor hypertension control in China.

A modified EDAS model for comparison of mobile wallet service providers in India

The present paper has two-fold purposes.First,the current work provides an integrated theoretical framework to compare popular mobile wallet service providers based on users’views in the Indian context.To this end,we propose a new grey correlationbased Picture Fuzzy-Evaluation based on Distance from Average Solution(GCPF-EDAS)framework for the comparative analysis.We integrate the fundamental framework of the Technology Acceptance Model and Unified theory of acceptance and use of technology vis-a-vis service quality dimensions for criteria selection.For comparative ranking,we conduct our analysis under uncertain environments using picture fuzzy numbers.We find that user-friendliness,a wide variety of use,and familiarity and awareness about the products help reduce the uncertainty factors and obtain positive impressions from the users.It is seen that PhonePe(A3),Google Pay(A2),Amazon Pay(A4)and PayTM(A1)hold top positions.For validation of the result,we first compare the ranking provided by our proposed model with that derived by using picture fuzzy score based extensions of EDAS and another widely used algorithm such as The Technique for Order of Preference by Similarity to Ideal Solution.We observe a significant consistency.We then carry out rank reversal test for GCPF-EDAS model.We notice that our proposed GCPF-EDAS model does not suffers from rank reversal phenomenon.To examine the stability in the result for further validation,we carry out the sensitivity analysis by varying the differentiating coefficient and exchanging the criteria weights.We find that our proposed method provides stable result for the present case study and performs better as ranking order does not get changed significantly with the changes in the given conditions.

Typhoon Case Comparison Analysis Between Heterogeneous Many-Core and Homogenous Multicore Supercomputing Platforms

In this paper,a typical experiment is carried out based on a high-resolution air-sea coupled model,namely,the coupled ocean-atmosphere-wave-sediment transport(COAWST)model,on both heterogeneous many-core(SW)and homogenous multicore(Intel)supercomputing platforms.We construct a hindcast of Typhoon Lekima on both the SW and Intel platforms,compare the simulation results between these two platforms and compare the key elements of the atmospheric and ocean modules to reanalysis data.The comparative experiment in this typhoon case indicates that the domestic many-core computing platform and general cluster yield almost no differences in the simulated typhoon path and intensity,and the differences in surface pressure(PSFC)in the WRF model and sea surface temperature(SST)in the short-range forecast are very small,whereas a major difference can be identified at high latitudes after the first 10 days.Further heat budget analysis verifies that the differences in SST after 10 days are mainly caused by shortwave radiation variations,as influenced by subsequently generated typhoons in the system.These typhoons generated in the hindcast after the first 10 days attain obviously different trajectories between the two platforms.

Social Comparison Orientation Associated with Psychological Well Being:The Mediated Role of Self-efficacy

The paper focused on how social comparison orientation people apply influences their psychological well-being and how self-efficacy plays an important role in buffering some negative influence from upward social comparison compared with someone better in one domain.In Festinger’s(1954)social comparison theory,the social comparison orientation instructed how people process the information they compared for,and related emotion was induced differently.In this paper,2,000 college students in Boston were proposed to participate in two experiments that discuss how different social comparison orientations affect their perception of life satisfaction.For the hypothetical result,we proposed that a high level of engagement in social comparison and ability-based social comparison was associated with less life satisfaction than the participants who had a low level of social comparison and opinion-based social comparison.In terms of coping strategy,we assumed that a high level of self-efficacy,which is the belief in capability to achieve a certain goal,will buffer the negative impact from upward comparison and improve the life satisfaction of those participants who like to engage with social comparison and ability-based comparison orientation.

A Comparison of Different Values of Freedom Reflected in the Characters of Sun Wukong and Dean

Both the characters of Sun Wukong in The Journey to the West,which is a traditional Chinese fiction,and Dean in On the Road,which is a typical American Beat Generation novel,have been pursuing a carefree lifestyle based on their living environments respectively,but their values of freedom bear quite different meanings:Sun Wukong tries his best to struggle for a happy life for all his family and his friends as well as for himself with little consideration of the risk of his own life,while Dean is always on his way at random for his own personal happiness with little consideration for anybody else.Therefore,Sun Wukong’s behavior represents a kind of collectivism within his individualism,while Dean’s act reflects his American free life style of individualism to a certain extent.

Brain Abscess Surgery Outcome: A Comparison between Craniotomy with Membrane Excision versus Burr Hole Aspiration

Introduction: Brain abscess represents 8% of intracranial masses in developing countries. Despite the advances in neuro-imaging, still, the diagnosis of brain abscess is difficult and may need a biopsy in most cases to verify the diagnosis because may even lead to death. CT scan with contrast is a good tool for diagnosing and localizing brain abscesses in late stages, however, it is difficult to diagnose them in the early stages. The development of MRI helps to more accurately diagnose brain abscess. Surgical management of brain abscesses is either medical or surgical through craniotomy or burr holes. Indications of each are still a point of debate among most neurosurgeons. Methodology: This is a descriptive longitudinal prospective study to compare the outcomes of two surgical procedures used in The National Centre for Neurological Sciences-Khartoum-Sudan (NCNS) from 2012 to 2015, craniotomy and excision of the abscess membrane versus burr hole and aspiration of brain abscess in terms of duration of hospitalization, length of antibiotic use, recurrence rate, number of images needed for follow-up, and the final postoperative early and late outcomes. The data was collected through a designed questionnaire and was then analyzed using SPSS version 20. No significant ethical approval was required for this study. Results: Fifty-four patients were operated on through craniotomy (29/54) and burr hole (25/54). Their ages ranged from 1 year to 53 years with an average presentation at 13 years of age. Most patients presented with fever (23.1%), convulsions (16%), vomiting (16.7%) and headache (15.4%). The mean of illness for both groups was almost 2 months. The majority of patients in this study were having no risk factors (38.9%) while the major risk factors seen were cardiac diseases (14.8%), neurosurgical procedures (13%) and otitis media (11.1%). As most patients presented late, the diagnosis of most was made using CT brain with contrast (83.3%). In most of the patients (85.2%) there were no organisms separated in the culture. 8/54 patients had positive cultures, 7/8 were bacterial and only one (1/8) was fungal. Most patients received antibiotics for 45 days postoperatively in both craniotomy and burr hole groups. When both groups were compared, those operated with craniotomy were found to have a relatively higher length of hospital stay, however, no significant difference was found between both groups. Also, it was found that those operated on with craniotomy had a high cure rate and less recurrence in comparison with burr hole group. Deterioration and death were significantly higher among craniotomy group. Only CT brain was used as the imaging modality of choice for follow-up in both groups for 4 months’ duration and it was noted that complete evacuation was significantly higher among craniotomy group while remnants were higher among burr hole group. Conclusion: Brain abscess is still a challenging condition for neurosurgeons in Sudan. The limited number of Sudanese neurosurgeons, neurosurgical centers and diagnostic facilities contributed to delay in diagnosing brain abscess in most patients. It is important to design a strict protocol and precautions for any neurosurgical operation or bedside procedure to prevent infection and subsequent brain abscess development. CT brain with contrast is a good imaging tool for assessing the size, site and stage of brain abscesses. No significant difference between craniotomy or burr hole for clearance from brain abscess in terms of antibiotic used or duration of hospital stay. However, burr hole aspiration is associated with higher rates of recurrences. On the other hand, craniotomy and excision have relatively higher neurologic morbidity postoperative with expectantly higher post-operative hospitalization but no differences in the final outcome. Therefore, the selection of surgical technique should be individualized in each case based on the abscess site size source patient fitness for surgery and neurosurgeon’s preference.

区块链产业发展:经济特性与中美路径差异

区块链具有去中心化、可追溯性两大核心特征和不可篡改、去信任化、信息透明、可匿名性四大衍生特征,并进一步引致出能够作用于经济领域的五大经济特性:减少信息不对称、降低组织的集中度、提供可置信的承诺、生成新的价值标的、减少交易成本。区块链是否能与产业良好融合是其能否有效发挥上述重要经济特性的一个重要因素。本文通过对中美区块链行业的对比分析发现,中国对于区块链的应用领域态度更为审慎,同时也具有更强的政策导向,主要应用领域为实体经济;而美国虽然对区块链的政策导向不如中国明显,但其在技术、人才培养等方面都具有显著优势,区块链应用规模在全球范围内处于绝对领先地位。总的来看,中国区块链产业发展面临审慎的金融政策与区块链特征不匹配、结合区块链与实体经济的配套设施相对缺失、区块链适用领域有待细化、区块链技术有待提升等问题。为进一步推动中国区块链产业发展,需要推动央行数字货币发展、加强数字化基础设施建设、针对性推动区块链行业发展、加强区块链技术基础研究。

不同比对方式下的洲际标准时间复现性能分析

中国科学院国家授时中心研制的标准时间复现系统具备支持洲际用户对标准时间频率信号的需求。本文以位于欧洲白俄罗斯明斯克的复现终端为分析对象,分析了共视、全视不同比对方式对复现时频信号性能的影响。对于洲际范围的时间复现,复现终端与参考端共同可视卫星数变少。单一卫星导航系统可利用的共视卫星数明显减少,GPS/BDS共视可明显增加可视卫星数量,提高共视时间比对精度,全视比对对两地共同可视卫星数没有要求。分析结果表明,单GPS全视比对就可以达到优于GPS/BDS的共视比对复现效果。受BDS卫星星间偏差的影响,基于单BDS全视比对的复现效果比GPS稍差,GPS/BDS全视比对效果略有改善。复现终端运行在GPS/BDS共视比对融合GPS全视比对模式复现的时频信号的性能最优,可以满足洲际范围内5 ns的时间同步要求,为后续洲际大尺度范围的标准时间复现终端的运行模式提供参考。

跨海桥梁基础波浪力断面对比与研究

桥梁基础在波浪环境下的施工安全关乎桥梁建设的稳定性,需要给予足够的重视。利用数值模拟手段,基于改进的RNG κ-ε模型,采用VOF法模拟自由液面,在保持相同迎浪断面的情况下,建立圆形、圆端形、矩形和多边形4种不同断面形式桥梁基础受波浪作用的三维数值模型,对比其受力差异,并结合流场数据加以分析。结果表明:相同波浪条件下4种不同断面形式的结构所受到水平波浪力中以圆形结构为最小,矩形结构为最大,其总水平波浪力幅值较圆形结构增大10%左右;桥梁基础结构在波浪的作用下,基础周围会受到绕流作用,使得结构部分位置处的流速增大并出现流速集中现象,在矩形结构周围这一现象最为突出,多边形结构的情况与之类似,而圆形及圆端形结构的流速集中现象则相对较弱;按规范计算得到的等效圆柱波浪力相较于数值模拟结果大23%~29%,按等效方柱计算得到的波浪力相较于数值模拟结果大10%~13%。从工程设计的角度看,采用圆弧形的结构设计有助于减小波浪荷载和削弱桥梁基础局部的流速增大与流速集中现象。