MULTI-PARAMETER HARDY SPACES VIA DISCRETE LITTLEWOOD-PALEY THEORY

In this paper, we apply a discrete Littlewood-Paley analysis to obtain Hardy spaces HP（Rn1× … ×Rnk） of arbitrary number of parameters characterized by discrete Littlewood-Paley square function and derive the boundedness of singular integral operators onHP（Rn1× … ×Rnk） and fromHP（Rn1× … ×Rnk）toLP（Rn1× … ×Rnk）.

Expansion modelling of discrete grey model based on multi-factor information aggregation

This paper aims to study a novel expansion discrete grey forecasting model, which could aggregate input information more effectively. In general, existing multi-factor grey forecasting models, such as one order and h variables grey forecasting model （GM （1, h））, always aggregate the main system variable and independent variables in a linear form rather than a nonlinear form, while a nonlinear form could be used in more cases than the linear form. And the nonlinear form could aggregate collinear independent factors, which widely lie in many multi-factor forecasting problems. To overcome this problem, a new approach, named as the Solow residual method, is proposed to aggregate independent factors. And a new expansion model, feedback multi-factor discrete grey forecasting model based on the Solow residual method （abbreviated as FDGM （1, h））, is proposed accordingly. Then the feedback control equation and the parameters＇ solution of the FDGM （1, h） model are given. Finally, a real application is used to test the modelling accuracy of the FDGM （1, h） model. Results show that the FDGM （1, h） model is much better than the nonhomogeneous discrete grey forecasting model （NDGM） and the GM （1, h） model.

Creation of Zero CO₂Emissions Residential Buildings due to Operating and Embodied Energy Use on the Island of Crete, Greece

The possibility of creating zero CO2 emissions residential buildings due to life cycle energy use in the island of Crete, Greece has been examined. In a typical residential building located in Crete, Greece, its annual operating energy has been appraised at 170 KWh/m2 and its embodied energy at 30 KWh/m2. Various locally available renewable energies including solar energy, solid biomass and low enthalpy geothermal energy with heat pumps have been considered for generating the required heat and offsetting the grid electricity used. Their technologies are mature, reliable and cost-effective. Offset of the annual grid electricity use in the building with solar-PV electricity is allowed according to the net metering regulation. For zero carbon emissions due to embodied energy of the building, generation of additional solar electricity injected into the grid is required. A mathematical model has been developed for sizing the required solar-PV system installed in the building in order to offset the grid electricity use. For a residential building in Crete, Greece with a covered area of 100 m2, the power of the additional solar-PV system has been estimated at 1.6 KWp and its cost at 2400 €. In the current work, it is indicated that the creation of a zero CO2 emissions residential building due to life cycle energy use in Crete, Greece does not have major difficulties and it could be achieved relatively easily.

Description and Assessment of a Small Renewable Energy Community in the Island of Crete, Greece

A description and assessment of a small renewable energy community located in Crete, Greece is presented. The community included private residential and agricultural activities without any involvement of the public sector. Small-scale decentralized energy systems were used. Solar energy and solid biomass which are locally available covered most of the heat and electricity requirements in the community. Renewable energy technologies used include solar thermal energy, solar-PV and solid biomass burning utilizing olive tree wood and olive kernel wood. These technologies are mature, reliable, well proven in Crete and cost-effective. Existing energy systems were generating 857,877 kWh per year covering 94.46% of the current energy requirements in the community, significantly reducing its emissions at 278,494 kg CO2 per year. The addition of a new solar-PV system with nominal power of 33.6 kWp could cover all the remaining electricity needs in the community, transforming it to a zero-CO2 emission community due to energy use. The total installation cost of the existing renewable energy systems in the community was estimated at 0.16€ per total kWh of thermal and electric energy generated annually and at 0.50€ per ton of CO2 emissions saved annually. Results indicated that the creation of the above-mentioned small local energy community is economically viable, environmental friendly and socially accepted. Therefore it could be replicated in other territories with similar availability of renewable energies, increasing their energy autonomy and sustainability.

THE FLEXURAL STRENGTH AND REINFORCING MECHANISM OF THE TOP-AND-BOTTOM-LAYERED STEEL FIBER CONCRETE

The mix proportions and strength ofplain concrete, top-and-hottoim layered steel fiber concrete and common steel fiber concrete are camparatively researched in this article. The influence of the quantity and place of steel fiber layer on the concrete's strength is systematically researched and the simulated analysis is made by computer.

Studies on the Electrification of the Transport Sector in the Island of Crete, Greece

The possibility of electrifying the transport sector in Crete, Greece has been investigated. Currently the conventional vehicles in Crete consume annually 316,872 tons of gasoline and diesel oil emitting 1,030,188 tons of CO2. Electrification of the transport sector in Crete will result in a decrease of imported fossil fuels use and a reduction of CO2 emissions. It will also increase the use of locally available renewable energies in electricity generation. If all the existing conventional vehicles in Crete were to be replaced by electric vehicles, the annual electricity requirements in their batteries would be 1,092,568 to 1,311,077 MWh depending on the type of battery. The energy demand of the electric cars could be covered with electricity generated by renewable energies including solar and wind energy which are abundant in the island. The batteries of the electric cars could be used as electricity storage devices facilitating the penetration of intermittent renewable energies, with distributed generation systems, into the smart electric grid of Crete. It has been estimated that the aggregated theoretical storage capacity of all the batteries would be 6.33 GWh and that the size of the solar-PV plants and wind energy systems, generating all the electricity required by electric vehicles, would be 728 to 874 MWp and 445 to 534 MW respectively.

Possibilities of Creating Net Zero Carbon Emissions Prisons in the Island of Crete, Greece

An increase in energy efficiency and a reduction of carbon emissions in buildings are prerequisites for mitigating climate change. Public buildings should be energy-refurbished for minimizing their energy use, complying with EU legislation and directives. The creation of net zero carbon emissions prisons in Crete, Greece with reference to the agricultural prison of Agia has been examined. The prison’s capacity is 178 offenders and the annual energy consumption has been estimated at 4000 KWh/prisoner. The use of a solar thermal system for hot water production and a solar-PV system for electricity generation has been proposed for generating the energy required in the prison. Two scenarios have been examined. In the first, the two solar energy systems would generate all the required energy in the prison, while in the second, the two solar energy systems would generate 50% of the annual required energy in the prison, and the rest would be produced by fossil fuels. A tree plantation, either with olive trees or with Eucalyptus trees, would be created for offsetting the carbon emissions due to fossil fuels used in the prison. The surface of the flat plate solar collectors in the solar thermal system has been estimated at 113.9 M2 to 227.8 M2 while its cost is at 34,170€ to 68,340€. The nominal power of the solar-PV system has been estimated at 151.9 KWp to 303.8 KWp while its cost is at 182,280€ to 364,560€. The area of the tree plantation sequestrating 50% of the current CO2 emissions due to fossil fuels use in the prison has been estimated at 14.74 ha for olive trees and at 5.9 ha for Eucalyptus trees. The results indicated that the energy refurbishment in Agia’s agricultural prison in Crete, Greece, in order to zero its annual net carbon emissions, is feasible.

Creation of Zero CO2 Emissions School Buildings Due to Energy Use in Crete-Greece

Decrease of energy consumption in buildings and increase of the share of renewable energies in them are currently technologically and economically feasible and it is promoted by E.U. policies. After 2019, all the new public buildings in EU countries must be near zero energy buildings reducing their energy consumption and CO2 emissions. Use of various renewable energies for heat and power generation in school buildings in Crete-Greece can result in zeroing their fossil fuels consumption and CO2 emissions. Purpose of the current work is to investigate the possibilities of creating zero CO2 emissions school buildings in Crete-Greece due to operational energy use in them. A methodology which allows the replacement of fossil fuels with renewable energies in school buildings is proposed. Solar energy, solid biomass and low enthalpy geothermal energy, which are abundant in Crete, can be used for that. School buildings in Greece consume significantly less energy, 68 KWh/m2 year, and emit less CO2, 28 kgCO2/m2 year, than the corresponding buildings in other countries. The installation cost of renewable energies systems in order to replace all fossil fuels used in school buildings in Crete-Greece and to zero their CO2 consumption due to energy use in them has been estimated at 47.42 - 87.71 €/m2, which corresponds to 1.69 - 3.13 €/kg CO2 saved.

Possibilities of Creating Zero CO2 Emissions Olive Pomace Plants Due to Energy Use in Crete, Greece

Olive pomace plants process olive paste, a waste product of olive mills which produces crude olive kernel oil and olive kernel wood. Olive kernel wood has very good burning characteristics, high heat content, low cost and it is used as a renewable solid fuel replacing liquid fuel and heating oil. Part of the produced olive kernel wood is consumed inside the factory for heat generation and the rest is sold to heat consumers. It has been estimated that a typical olive pomace plant located in Crete, Greece consumes 42.86% of the produced olive kernel wood for its own heat generation, while the remaining 57.14% is sold to various heat consumers. 99.1% of the energy used in these plants is consumed for heating and the rest, 0.9%, for lighting and the operation of various electric devices. Olive pomace plants utilize a renewable solid fuel, which is carbon neutral, for the production of thermal energy. Therefore their CO2 emissions regarding energy utilization are due to electricity use. Installation of solar-PV panels in the plant could generate annually all the electricity needed for its operation. The current legal framework in Greece through net-metering allows the offsetting of grid electricity consumed in factories with PV electricity. The required capital cost of a solar-PV system installed in a typical olive pomace plant located in Crete, Greece in order to offset the grid electricity consumed annually has been estimated at 185,832€, the payback period of 5.33 years and the net present value at 555,671€. Since the plant could utilize only solid biomass for heat generation and could offset the grid electricity consumption with solar electricity, its total CO2 emissions due to energy use would be zero contributing positively to climate stabilization.

Epigenetic inactivation of secreted frizzled-related protein 2 in esophageal squamous cell carcinoma

AIM:To investigate the expression and methylation status of the secreted frizzled-related protein 2(SFRP2) in esophageal squamous cell carcinoma(ESCC) and explore its role in ESCC carcinogenesis.METHODS:Seven ESCC cell lines(KYSE 30,KYSE150,KYSE410,KYSE510,EC109,EC9706 and TE-1) and one immortalized human esophageal epithelial cell line(Het1A),20 ESCC tissue samples and 20 paired adjacent non-tumor esophageal epithelial tissues were analyzed in this study.Reverse-transcription polymerase chain reaction(RT-PCR) was employed to investigate the expression of SFRP2 in cell lines,primary ESCC tumor tissue,and paired adjacent normal tissue.Methylation status was evaluated by methylation-specific PCR and bisulfite sequencing.The correlation between expression and promoter methylation of the SFRP2 gene was confirmed with treatment of 5-aza-2'-deoxycytidine.To assess the potential role of SFRP2 in ESCC,we es-tablished stable SFRP2-transfected cells and examined them with regard to cell proliferation,colony formation,apoptosis and cell cycle in vivo and in vitro.RESULTS:SFRP2 mRNA was expressed in the immortalized normal esophageal epithelial cell line but not in seven ESCC cell lines.By methylation-specific PCR,complete methylation was detected in three cell lines with silenced SFRP2 expression,and extensive methylation was observed in the other four ESCC cell lines.5-aza-2'-deoxycytidine could restore the expression of SFRP2 mRNA in the three ESCC cell lines lacking SFRP2 expression.SFRP2 mRNA expression was obviously lower in primary ESCC tissue than in adjacent normal tissue(0.939 ± 0.398 vs 1.51 ± 0.399,P < 0.01).SFRP2 methylation was higher in tumor tissue than in paired normal tissue(95% vs 65%,P < 0.05).The DNA methylation status of the SFRP2 correlated inversely with the SFRP2 expression.To assess the potential role of SFRP2 in ESCC,we established stable SFRP2 transfectants and control counterparts by introducing pcDNA3.1/v5 hisA-SFRP2 or pcDNA3.1/v5 hisA-empty vector into KYSE30 cells lacking SFRP2 expression.After transfection,the forced-expression of SFRP2 was confirmed by the RT-PCR.In comparison with the control groups,stably-expressed SFRP2 in KYSE 30 cells significantly reduced colony formation in vitro(47.17% ± 15.61% vs 17% ± 3.6%,P = 0.031) and tumor growth in nude mice(917.86 ± 249.35 mm 3 vs 337.23 ± 124.43 mm 3,P < 0.05).Using flow cytometry analysis,we found a significantly higher number of early apoptotic cells in SFRP2-transfected cells than in the control cells(P = 0.025).The mean cell number in the S and G2-M phases of the cell cycle was also significantly lower in SFRP2-transfected KYSE30 cells compared with mock transfected counterparts.CONCLUSION:Silencing of SFRP2 expression through promoter hypermethylation may be a factor in ESCC carcinogenesis through loss of its tumor-suppressive activity.

不确定非线性离散系统指令滤波事件触发控制

本文提出了考虑输入饱和的一类不确定非线性离散系统的事件触发指令滤波控制方法.采用指令滤波控制技术解决了传统反步法存在的“因果矛盾”问题,引入补偿机制提高了系统的控制精度;利用事件触发机制能够避免自适应律和控制律的频繁更新,降低了计算负担,提高了资源利用率;运用模糊逻辑系统逼近系统中未知的非线性函数;结合李雅普诺夫稳定性理论,验证了提出的控制方案能够保证跟踪误差收敛到原点小的邻域内以及闭环系统的所有信号有界.仿真结果表明,本文提出的控制方法具有较强的鲁棒性及较好的跟踪性能.

希腊克里特MW6.0地震后的应力方向变化与强余震发生

地震的震源机制是地壳应力变化的指示器,而地壳应力变化与强震的发生直接相关。前人研究了地震震源机制变化在视应力较高的走滑型大震前的应力变化过程,而未见到震源机制变化对视应力较低的正断型大震发生的指示作用的研究。文章以2021年希腊克里特M W6.0正断型地震序列为例,通过计算地震序列震源机制解与区域应力场方向之间最小空间旋转角的变化,揭示应力变化与强震发生的关系。为保证震源机制解的准确性,采用多家机构确定的震源机制得到中心震源机制作为该地震的震源机制,而后采用该地震序列精确的震源机制求解当地应力场,最后计算地震震源机制与主震震源机制及与所估计的地壳应力场方向的空间旋转角随时间的变化,探索强震发生与应力场变化的关系。结果表明:在主震发生的短期内,余震震源机制与该区域应力场方向的空间旋转角较大,与其后小震级的弱地震活动对应;随后余震震源机制与应力场方向的空间旋转角减小,对应后面发生的3次M W>5.0的强余震,在此之后的长时间内余震震源机制和应力场方向的空间旋转角再次增大,对应的余震震级及频度皆明显下降。文章以2021年希腊克里特M W6.0地震序列为例,发现视应力较低的正断型地震前也存在应力方向集中现象,为探索地震应力前兆提供了范例。

聚乙烯醇纤维对排水渠底细石混凝土的性能影响

为进一步降低排水渠底的磨损,将聚乙烯醇纤维掺入细石混凝土,分析细石混凝土各项性能与聚乙烯醇纤维掺量之间的关系,分别设计试验探究混凝土扩展度、劈裂抗拉强度、抗压强度和抗折强度等的发展变化。试验结果显示:聚乙烯醇纤维的掺加能够有效降低混凝土的扩展度,提升劈裂抗拉强度与抗折强度,且纤维掺量越高变化幅度越大;所使用的混凝土强度等级高也会有效提升纤维掺加对细石混凝土性能的改良效果;细石混凝土抗压强度随聚乙烯醇纤维掺量提升而表现出前期增加后期降低的发展趋势,其中抗压强度峰值出现于掺加0.8 kg/m^(3)聚乙烯醇纤维时。

Assessment of water-induced soil erosion as a threat to cultural heritage sites:the case of Chania prefecture,Crete Island,Greece

Among the environmental threats,the intensification of natural hazards,such as soil erosion may threaten the integrity and value of cultural heritage sites.In this framework,the present study’s main objective was to identify archaeological sites susceptible by soil erosion,taking the case study of Chania prefecture in Crete Island.Remotely sensed and other available geospatial datasets were analyzed in a GIS-based empirical model,namely Unit Stream Power Erosion and Deposition(USPED),to estimate the average annual soil loss and deposition rates due to waterinduced erosion in the study area.The resultant erosion map was then intersected with the locations and surrounding zones of the known archaeological sites for identifying the sites and the portions of their vicinity being at risk.The results revealed that Chania prefecture and its cultural heritage are significantly affected by both soil loss and deposition processes.Between the two processes,soil loss was found to be more intensive,influencing a larger part of the prefecture(especially to the west)as well as a higher amount of archaeological sites.The extreme and high soil loss classes were also detected to cover the most considerable portion of the sites’surrounding area.The identification of the archaeological sites being most exposed to soil erosion hazard can constitute a basis for cultural heritage managers in order to take preventive preserva-tion measures and develop specific risk mitigation strategies.

泸定6.8级地震农村居住建筑震害调查与分析

2022年9月5日,四川省泸定县发生了6.8级地震,对泸定、石棉、汉源等地区的农村建筑造成严重影响。为了分析农村建筑的震害,对评估烈度为Ⅵ~Ⅸ度区域12个乡镇35个地点的农村建筑进行了现场调查,总结了砖砌体结构、木结构、石结构和生土结构的典型震害特征,并对4种结构的震害等级进行了统计和分析。结果表明:砖砌体结构房屋的严重破坏及倒塌占比为4.2%和3.3%,且与构造措施有很大关系,未经正规设计且缺乏构造措施的砌体结构出现屋面破坏、局部甚至整体倒塌,但设有构造措施的砌体结构房屋保存较好;木结构建筑整体受损较轻,但由于本次泸定地震的竖向作用强烈,木屋盖破坏较为严重;石砌体结构和生土结构房屋,发生严重破坏和倒塌的比例较高,严重破坏占比分别为7.2%和5.1%,倒塌占比分别为10%和7%,破坏最为严重。山体滑坡、落石等次生灾害对建筑造成不同程度的损坏,是此次泸定地震的特征之一。针对此次泸定地震的破坏特征,建议农村建筑落实抗震措施,引入适用的新工艺;灾后恢复过程中,以房屋震损程度评估为基础,重建与加固相结合;同时,建议注重农村规划、选址的研究,降低地震次生灾害破坏;应当进行抗震科普宣传,加强农村工匠培训。

基于差分隐私保护的服务机器人视觉图像发布算法

为保护服务机器人视觉图像中的敏感个人信息,提出了一种基于离散余弦变换与差分隐私技术相结合的服务机器人图像发布算法。首先,利用离散余弦变换压缩图像,为均衡相关噪声误差和重构误差,引入一种基于随机梯度下降算法的系数选择方法,从而在相应的系数空间中选择出合适的系数来压缩图像;其次,对系数空间添加拉普拉斯噪声来满足ε-差分隐私需求;再次,基于4种真实的室内图像数据集采用小波包变换和最小二乘支持向量机分类技术从算法的查准率等指标上衡量算法。实验结果表明,所提出的图像发布算法有较好的鲁棒性。

《荷马史诗》中头盔描写真实性的历史考辨:传说与考古的互证

头盔是《荷马史诗》里英雄们的重要武器装备之一。通过词语统计的方式,从材质、装饰、作用、性能等方面对《荷马史诗》文本中的头盔进行了归纳总结,发现史诗中描写的头盔以铜制为主,皮制为辅,铜脸颊和马鬃冠是常见的装饰,其作用除了战场防护,还可用于威慑、抓阄、炫富,等等。结合考古证据,以考察史诗中所写头盔在现实世界中是否有其原型,并比较了史诗中头盔和现实中头盔的异同。经比较可知,《荷马史诗》中所写的头盔确有现实原型,对头盔的描述有诸多准确之处,这些都得到了后世考古出土材料的证实。但在材质上二者也存在重大差异,这种差异体现出希腊地区青铜器技术的发展。“‘盔’一斑而知全豹”,从古希腊头盔的历史演变可以透视其文化与文明发展的盛衰。

Cahn-Hilliard方程的自适应间断有限体积元法

Cahn-Hilliard方程是一类重要的四阶非线性扩散方程,具有丰富的物理背景和深刻的研究价值,但方程的非线性势项f(u)的存在以及小参数ε导致的强刚性会给数值模拟带来诸多挑战,因此设计高效、准确的数值方案满足方程离散能量定律是非常重要的.间断有限体积元方法(DFVEM)采用低阶元,具有精度高、操作简单、适合工程应用的网格自适应等优点.该文对Cahn-Hilliard方程利用DFVEM结合全隐格式进行求解,证明了全离散格式质量守恒和能量耗散的重要理论结果.数值实验提出一种自适应时间步进策略,验证了方法的有效性.

石油仓储场所防火防爆及消防安全管理

通过对现有石油仓储场所的细致调查,可发现其防火防爆及消防安全管理中存在一些不容忽视的问题,尤其是一些场所的消防设施老旧,不能有效地起到防火防爆的作用;还有一些场所的消防安全管理制度不够完善,员工缺乏必要的消防安全培训等,导致在事故发生时无法及时有效地应对。文章针对石油仓储场所的防火防爆及消防安全管理问题进行了深入研究,通过对现有石油仓储场所的调查和分析,结合相关消防安全管理中存在的问题,提出了相应的解决措施,旨在提高石油仓储场所的安全管理水平,预防和减少火灾、爆炸等事故的发生,保障人民生命和财产安全。

水泥土复合管桩抗拔设计的探讨

结合工程实例,介绍了水泥土复合管桩抗拔的基本原理和特性。为了便于抗拔承载力及经济效益的对比,在同一场地,试桩方案设计水泥土复合管桩2种桩型共6根,以及钻孔灌注桩2种桩型共5根,对其分别进行单桩抗拔静力载荷试验,通过对试验结果和基桩施工造价的分析后认为,在提供相同抗拔承载力特征值时,水泥土复合管桩上拔位移量是钻孔灌注桩的1/3,而造价仅为钻孔灌注桩的80%;管桩的顶部连接采用张拉机械套筒连接是安全可靠的。采用水泥土复合管桩以达到降低工程投资、提高施工质量和保护环境的目的。