Predicting Net Cross-Shore Total Load Transport: A Phase-Averaging, Quasi-Steady Approach Incorporating Undertow Contribution

Wave shapes that induce velocity skewness and acceleration asymmetry are usually responsible for onshore sediment transport, whereas undertow and bottom slope effect normally contribute to offshore sediment transport. By incorporating these counteracting driving forces in a phase-averaged manner, the theoretically-based quasi-steady formula of Wang （2007） is modified to predict the magnitude and direction of net cross-shore total load transport under the coaction of wave and current. The predictions show an excellent agreement with the measurement data on medium and fine sand collected by Dohmen-Janssen and Hanes （2002） and Schretlen （2012） in a full-scale wave flume at the Coastal Research Centre in Hannover, Germany. The modified formula can predict the net onshore transport of fine sand in sheet flows. In particular, it can predict the net offshore transport of medium sand in rippled beds through enlarged bed roughness, as well as the net offshore transport of fine-to-coarse sand in sheet flows with the aid of a new criterion to judge the occurrence of net offshore transport.

TaNRT2.1-6B is a dual-affinity nitrate transporter contributing to nitrogen uptake in bread wheat under both nitrogen deficiency and sufficiency

Multiple nitrate transporter(NRT)genes exist in the genome of bread wheat,and it is of great importance to identify the elite NRT genes for N-efficient wheat cultivar breeding.A candidate gene association study(CGAS)of six N use efficiency(NUE)related traits(grain N concentration(GNC),straw N concentration(SNC),grain yield(GY),grain N accumulation(GNA),shoot total N accumulation(STN)and N harvest index(NHI))was performed based on SNPs in 46 NRT2 genes using a panel composed of 286 wheat cultivars.CGAS identified TaNRT2.1-6B as an elite NRT gene that is significantly associated with four(NHI,SNC,GNA and GY)of the six NUE-related traits simultaneously.TaNRT2.1-6B is located on the plasma membrane and acts as a dual-affinity NRT.The overexpression of TaNRT2.1-6B increased the N influx and root growth of wheat,whereas gene silence lines resulted in the opposite effects.The overexpression of TaNRT2.1-6B also improved GY and N accumulation of wheat under either limited or sufficient N conditions.The data provide the TaNRT2.1-6B gene and the two associated SNP markers as promising powerful tools for breeding wheat cultivars with high N uptake ability and NUE.

Influence of gas transport mechanisms on the productivity of multi-stage fractured horizontal wells in shale gas reservoirs

In order to investigate the influence on shale gas well productivity caused by gas transport in nanometer- size pores, a mathematical model of multi-stage fractured horizontal wells in shale gas reservoirs is built, which considers the influence of viscous flow, Knudsen diffusion, surface diffusion, and adsorption layer thickness. A dis- crete-fracture model is used to simplify the fracture mod- cling, and a finite element method is applied to solve the model. The numerical simulation results indicate that with a decrease in the intrinsic matrix permeability, Knudsen diffusion and surface diffusion contributions to production become large and cannot be ignored. The existence of an adsorption layer on the nanopore surfaces reduces the effective pore radius and the effective porosity, resulting in low production from fractured horizontal wells. With a decrease in the pore radius, considering the adsorption layer, the production reduction rate increases. When the pore radius is less than 10 nm, because of the combined impacts of Knudsen diffusion, surface diffusion, and adsorption layers, the production of multi-stage fractured horizontal wells increases with a decrease in the pore pressure. When the pore pressure is lower than 30 MPa, the rate of production increase becomes larger with a decrease in pore pressure.

Solvents incubatedπ-πstacking in hole transport layer for perovskite-silicon 2-terminal tandem solar cells with 27.21%efficiency

Room temperature sputtered inorganic nickel oxide(NiO_(x))is one of the most promising hole transport layers(HTL)for perovskite-sillion 2-terminal tandem solar cells with the aid of ultrathin and compact organic layers to passivate the surface defects.In this study,the aromatic solvent with different substituent groups was used to regulate the conformation of poly[bis(4-phenyl)(2,4,6-trimethylphenyl)am ine](PTAA)layer.As a result,the single-junction perovskite solar cell(PSC)gained a power conversion efficiency(PCE)of 20.63%,contributing to a 27.21%efficiency for monolithic perovskite/silicon(double-side polished)2-terminal tandem solar cell,by applying the alkyl aromatic solvent to enhance theπ-πstacking of PTAA molecular chains.The tandem solar cell can maintain 95%initial efficiency after aging over 1000 h.This study provides a universal approach for improving the photovoltaic performance of NiO_(x)/polymer-based perovskite/silicon tandem solar cells and other single junction inverted PSCs.

Relationship Between Serum microRNA-372-3p and Glucose Transporter 4 Levels and Insulin Resistance in Gestational Diabetes Mellitus

Objective:To observe the changes in insulin resistance in patients with gestational diabetes mellitus(GDM)based on the detection of serum microRNA-372-3p and glucose transporter protein 4(GLUT4)levels.Methods:We conducted a retrospective cohort study of 42 patients who were diagnosed with GDM and hospitalized in our hospital during the period from January 2017 to December 2021 and another 42 patients who had normal pregnancy during the same period by collecting their clinical data.We analyzed their serum microRNA expression profiles and miR-372-3p levels to study the relationship between GDM and insulin resistance.Results:The relative expression of miR-372-3p in the serum of patients in the GDM group was significantly higher than that of patients in the control group,but the GLUT 4 level of the GDM group was significantly lower than that of the control group(P<0.05).Compared with the control group,the GDM group had significantly higher levels of fasting blood glucose(FBG),fasting insulin(FINS),2-hour postprandial blood glucose(2h-BG),total cholesterol(TC),triglyceride(TG),and homeostatic model assessment for insulin resistance(HOMA-IR)index but significantly lower homeostasis model assessment ofβ-cell function(HOMA-β)index(P<0.05).The relative expression of miR-372-3p in serum was independently and positively correlated with HOMA-IR,while the level of GLUT4 was independently and negatively correlated with HOMA-IR(P<0.05).Conclusion:Glycosylated hemoglobin test in the early stages of pregnancy(12–13 weeks of gestation)is important to ensure the health of pregnant women and fetuses.The screening and intervention for elevated glucose in pregnant women act as a guideline for the treatment of GDM.Patients with insulin resistance and related complications such as hyperinsulinemia and hypoglycemia should be given priority.

Effects of Hemp seed soft capsule on colonic ion transport in rats

AIM To investigate the effect of Hemp seed soft capsule(HSCC) on colonic ion transport and its related mechanisms in constipation rats.METHODS Sprague-Dawley male rats were randomly divided into three groups: normal group, constipation group and HSSC group. Rats in the constipation and HSSC groups were administrated loperamide 3 mg/kg per day orally for 12 d to induce the constipation model. Then, the HSSC group was given HSSC 0.126 g/kg per day by gavage for 7 d. The normal and constipation groups were treated with distilled water. After the treatment, the fecal wet weight and water content were measured. The basal short-circuit current(Isc) and resistance were measured by an Ussing Chamber. Besides the in vivo drug delivery experiment above, an in vitro drug application experiment was also conducted. The accumulative concentrations of HSSC(0.1 mg/m L, 0.5 mg/m L, 1.0 mg/m L, 2.5 mg/m L, 5.0 mg/m L, 10.0 mg/m L and 25.0 mg/m L) were added to the normal isolatedcolonic mucosa and the Isc was recorded. Further, after the application of either ion(Cl^-or HCO_3^-) substitution, ion channel-related inhibitor(N-phenylanthranilic acid, glybenclamide, 4,4-diisothiocyano-2,2-stilbenedisulfonic acid or bumetanide) or neural pathway inhibitor [tetrodotoxin(TTX), atropine, or hexamethonium], the Isc induced by HSSC was also measured. RESULTS In the constipation group, the fecal wet weight and the water content were decreased in comparison with the normal group(P < 0.01). After the treatment with HSSC, the fecal wet weight and the water content in the HSSC group were increased, compared with the constipation group(P < 0.01). In the constipation group, the basal Isc was decreased and resistance was increased, in comparison with the normal group(P < 0.01). After the treatment with HSSC, the basal Isc was increased(P < 0.05) and resistance was decreased(P < 0.01) in the HSSC group compared with the constipation group. In the in vitro experiment, beginning with the concentration of 1.0 mg/m L, differences in Isc were found between the experimental mucosa(with HSSC added) and control mucosa. The Isc of experimental mucosa was higher than that of control mucosa under the same concentration(1.0 mg/m L, P < 0.05; 2.5-25 mg/m L, P < 0.01). After the Cl^-or HCO_3^-removal and pretreated with different inhibitors(c AMPdependent and Ca^(2+)-dependent Cl^-channels, Na^+-K^+-2 Cl^-cotransporter(NKCC), Na^+-HCO_3^-cotransporter or Cl^-/HCO_3^-exchanger inhibitor), there were differences between experimental mucosa and control mucosa; the Isc of experimental mucosa was lower than that of control mucosa under the same concentration(P < 0.05). Meanwhile, after pretreatment with neural pathway inhibitor(TTX, atropine, or hexamethonium), there were no differences between experimental mucosa and control mucosa under the same concentration(P > 0.05).CONCLUSION HSSC ameliorates constipation by increasing colonic secretion, which is mediated via the coaction of c AMPdependent and Ca^(2+)-dependent Cl^-channels, NKCC, Na^+-HCO_3^-cotransporter or Cl^-/HCO_3^-exchanger.

Permeation Characteristics of Light Hydrocarbons Through Poly（amide-6-β-ethylene oxide） Multilayer Composite Membranes

In this paper, poly(amide-6-β-ethylene oxide) (PEBA1657) copolymer was used to prepare multilayer polyetherimide (PEI)/polydimethylsiloxane (PDMS)/PEBA1657/PDMS composite membranes by dip-coating method. Permeation behaviors of ethylene, ethane, propylene, propane, n-butane, methane and nitrogen through the multilayer composite membranes were investigated over a range of operating temperature and pressure. The permeances of light hydrocarbons through PEI/PDMS/PEBA1657/PDMS composite membranes increase with their increasing condensability, and the olefins are more permeable than their corresponding paraffins. For light hydrocarbons, the gas permeances increase significantly as temperature increasing. When the transmembrane pressure difference increases, the gas permeance increases moderately due to plasticization effect, while their apparent activation energies for permeation decrease.

水路交通系统的发展现状与未来展望

水路交通系统是以船舶等为载运工具、以港口为节点、以海洋、江河、湖泊等水域为通道的一种运输方式,能够实现货物、人员的搭载与时空位移,是综合交通体系中不可或缺的重要组成部分。本文分析了国内外水路交通系统发展现状,梳理了水路交通系统未来需求及技术特征,提出了水路交通运输规划与组织优化、绿色船舶动力系统及供给体系、人机共融船舶岸基驾控系统、海域立体综合运输系统、水路交通系统控制体系、气象导航与安全航行等未来水路交通系统发展方向,为提高水路交通系统运营效率与服务质量提供理论基础与技术参考。

Comparative Analysis of the Erosion Mechanism of Different Profiles in the Arcuate Foreshore under Typhoon Action

The comparison results of three beach profile data repeatedly measured before and after the typhoon in Shuidong Bay,west Guangdong province which show that there are significant differences in beach profile erosion and response process.And the changes of beach profile can be divided into:strong downward overall low shoreline regressive type and overall slight erosion shoreline regressive type.Application of the modified mildslope equation along three beach profile are simulated wave high reflection to the sea side,to the section vertical shore pressure gradient and including water roll force and radiation stress,the vertical shore forces one dimensional profile along the momentum conservation equation(radiation stress and water roll force)bottom friction and lateral mixing reaction between numerical solution,the momentum conservation equations of the wave increases the water flow velocity and section along the profile distribution of wave height and related forces.The analysis shows that the extent and difference of coastal erosion depend on the shoreline erosion mode stimulated by the maximum surge water of the coastal current and the maximum velocity of the coastal current and the dynamic state of the profile topography under the action of the profile location,morphology and incident wave elements.

Thermoelectric properties of Sr_(0.61)Ba_(0.39)Nb_2O_(6-δ) ceramics in different oxygen-reduction conditions

The thermoelectric properties of Sr0.61Ba0.39Nb2O6-δ ceramics, reduced in different conditions, are investigated in the temperature range from 323 K to 1073 K. The electrical transport behaviors of the samples are dominated by the thermal-activated polaron hopping in the low temperature range, the Fermi glass behavior in the middle temperature range, and the Anderson localized behavior in the high temperature range. The thermal conductivity presents a plateau at high- temperatures, indicating a glass-like thermal conduction behavior. Both the thermoelectric power factor and the thermal conductivity increase with the increase of the degree of oxygen-reduction. Taking these two factors into account, the oxygen-reduction can still contribute to promoting the thermoelectric figure of merit. The highest ZT value is obtained to be -0.19 at 1073 K in the heaviest oxygen reduced sample.

新一代航运系统的未来船舶技术展望

未来船舶技术对于新一代航运系统至关重要。为推动国际海事组织IMO所提出的航运智能化与绿色化进程,展望未来船舶技术发展方向。探讨未来船舶跨域协同架构关键技术,提出未来船舶发展的首要任务。明确以“船-岸-云”技术架构及“岸基驾控为主、船端值守为辅”运行模式为核心的未来船舶发展目标。强调我国应加快相关领域关键技术攻关,构建船舶岸基驾控系统,促进多领域合作,持续向造船强国和航运强国的发展目标迈进。

船舶岸电政策下港航企业低碳行为演化研究

为探究港航企业在船舶岸电政策下推进岸电应用的低碳行为演化路径,构建政府、港口企业、航运公司三方参与的演化博弈模型,判断在有限理性条件下各主体决策选择行为的稳定性状态,并通过MATLAB数值仿真分析政策变化对系统演化路径的影响。研究表明:系统存在3个稳定均衡点,分别对应船舶岸电发展过程中的三个阶段,初期、中期、成熟期;政府在推进船舶岸电发展中起主导作用,其积极制定并落实相关政策可促进港航企业选择使用岸电。针对货运码头岸电使用率较低的现状,补贴力度比监管力度作用更强,后期政府应加大对岸电使用的系列补贴。

Molecule-based vertical transistor via intermolecular charge transport throughπ-πstacking

Theπ-πstacking is a well-recognized intermolecular interaction that is responsible for the construction of electron hopping channels in numerous conducting frameworks/aggregates.However,the exact role ofπ-to-πchannels within typical single crystalline organic semiconductors remains unclear as the orientations of these molecules are diverse,and their control usually requires additional side chain groups that misrepresent the intrinsic properties of the original semiconducting molecules.Therefore,the construction of conduction channels with intrinsicπ-πstacking in the molecule-based device is crucial for the utilization of their unique transport characteristics and understanding of the transport mechanism.To this end,we present a molecular intercalation strategy that integrates two-dimensional layered materials with functional organic semiconductor molecules for functional molecule-based electronics.Various organic semiconductor molecules can be effectively intercalated into the van der Waals gaps of semi-metallic TaS_(2) withπ-πstacking configuration and controlled intercalant content.Our results show that the vertical charge transport in the stacking direction shows a tunneling-dominated mechanism that strongly depends on the molecular structures.Furthermore,we demonstrated a new type of molecule-based vertical transistor in which TaS_(2) andπ-πstacked organic molecules function as the electrical contact and the active channel,respectively.On/off ratios as high as 447 are achieved under electrostatic modulation in ionic liquid,comparable to the current state-of-the-art molecular transistors.Our study provides an ideal platform for probing intrinsic charge transport acrossπ-πstacked conjugated molecules and also a feasible approach for the construction of high-performance molecule-based electronic devices.

海啸波作用下泥沙运动——Ⅰ.岸滩剖面变化分析

在波浪水槽实验的基础上,对海啸波作用下的岸滩剖面演变规律开展研究。实验采用1/10～1/20的组合坡度,考虑3种不同的水深,选取N波作为入射波,同时采用规则波和非规则波进行对比研究。实验对波高、波浪的上爬、回落和水跃过程、每个波作用后的地形进行了测量和记录。研究结果表明,水动力特性的不同造成了N波与规则波和不规则波作用下不同的岸滩剖面演变特点。N波作用下发生了明显的岸滩冲刷和淤积,水流回落时滩肩发生冲刷,高速薄层回流和出渗水流作用是滩肩冲刷的主要原因,离岸区水跃发生水流挟沙力降低,泥沙淤积呈沙坝剖面。

新一代航运系统体系架构与关键技术研究

文章综述了近年来国内外绿色智能航运领域的研究进展和工程实践现状,包括业界在载运装备、基础设施、运营服务等方面的最新研究成果和绿色化、智能化技术应用情况,总结了当前发展中存在的问题和技术瓶颈。面向未来水路运输发展的需求和挑战,提出新一代航运系统的定义及其绿色化、智能化、韧性化的特征;通过梳理分析新一代航运系统的基本内涵,设计了系统的体系架构,运用信息物理系统的方法理论,将层级结构划分为:要素单元级、功能系统级及架构集成级;阐述了系统的核心组分:绿色智能船舶、数字生态设施、可靠岸基支持和韧性运营服务,给出系统的整体框架。在梳理分析系统基本服务和功能逻辑的基础上,阐述该系统物理“船-港-货”、信息“人-机-环”的运行模式,明确了运输船舶组织运营“岸基驾控为主,船端值守为辅”的航运新业态,凝练了航运系统规划设计技术、绿色智能航运装备技术、数字生态航道建养技术、船舶运行智能控制技术、交通运营组织技术、水上应急救援技术,及测试验证评估技术等关键技术;通过构建数字化的创新技术体系,能够支撑“人-船-岸-云”的高度协同,实现信息互联、系统共建和体系性创新,促进航运科技高质量发展。提出水路运输未来的变革性方向,研究成果可以有效指导新一代航运系统的规划设计与建设应用,为自立自强的水路运输技术研究和标准体系构建提供有力支撑。

闽粤交界的大埕湾岸滩稳定分析及岸滩防护对策

本文在实地调查的基础上,通过对大埕湾沿岸输沙率变化和岸线形态的分析,综合探讨了该海湾的泥沙来源,沿岸泥沙迁移特征,岸滩冲淤动态以及海岸的演变趋势.结果表明:该湾沿岸带形成了一股朝W向迁移的波生泥沙流,泥沙主要来自诏安湾和宫口湾;该湾海岸除东部沙坝泻湖岸段略有淤伸外,其余岸段均处于侵蚀状态;随着泥沙来源的减少,海岸内凹蚀退是今后岸线调整的自然过程.文中还对大埕湾岸滩的防侵蚀提出了相应的对策建议.

波浪作用下渤海湾近岸海域污染物的输移扩散规律

用物理模型实验和数学模型计算相结合的方法 ,研究了均匀缓坡岸滩上 ,规则波及不规则波浪作用下形成的沿岸流及其对岸边排放污染物输移扩散的影响。针对渤海湾的地形和主要波浪方向 ,研究了渤海湾主要排污口附近单纯波浪以及波浪、潮流共同作用下近岸海域内流动速度分布与相应污染物输移扩散规律。结果表明 ,在渤海湾近岸海域 (一定范围内 ) ,污染物输移扩散受到波浪作用的影响 ,表现为平行岸线方向。波浪作用使得远离污染物排放口的滩涂受污染的影响增大。

沿岸输沙计算研究综述

沿岸流输沙是波浪和波生沿岸流共同作用引起的沿岸纵向泥沙运动,是海岸带重要的泥沙搬运方式。自20世纪50年代以来,国内外许多学者对这一课题进行了研究,产生了很多理论公式,本文简要分析了各家的理论思想,根据不同的研究思想将诸多公式分类,简单论述了这些公式的优劣和实用性,并提出了一些沿岸流输沙研究中存在的问题。在文章的最后,介绍了理想沙质海滩稳定曲线的研究进展,并对其中存在的问题做了简单阐述。

大风浪影响下海域泥沙输运异变数值模拟

基于实测的水深、潮流、悬浮体、底质数据及历史气象资料等,采用导入SWAN波浪参数的ECOMSED三维模型,模拟大风浪对小清河口附近海域悬浮体浓度和底床冲淤变化的影响程度。并利用全潮水文观测资料对水动力和输沙率模拟结果进行检验,对比分析表明计算值与实测值吻合良好。模拟结果表明,大风浪影响下近岸海域泥沙输运变化较大,悬浮体浓度可达一般天气的10倍左右,而底床冲淤变化可达平时的百余倍。大风浪期间剧烈的底床冲淤变化对河口拦门沙演化影响较大。