Dynamic response of mountain tunnel,bridge,and embankment along the Sichuan-Tibet transportation corridor to active fault based on model tests

The Sichuan-Tibet transportation corridor is prone to numerous active faults and frequent strong earthquakes.While extensive studies have individually explored the effect of active faults and strong earthquakes on different engineering structures,their combined effect remains unclear.This research employed multiple physical model tests to investigate the dynamic response of various engineering structures,including tunnels,bridges,and embankments,under the simultaneous influence of cumulative earthquakes and stick-slip misalignment of an active fault.The prototype selected for this study was the Kanding No.2 tunnel,which crosses the Yunongxi fault zone within the Sichuan-Tibet transportation corridor.The results demonstrated that the tunnel,bridge,and embankment exhibited amplification in response to the input seismic wave,with the amplification effect gradually decreasing as the input peak ground acceleration(PGA)increased.The PGAs of different engineering structures were weakened by the fault rupture zone.Nevertheless,the misalignment of the active fault may decrease the overall stiffness of the engineering structure,leading to more severe damage,with a small contribution from seismic vibration.Additionally,the seismic vibration effect might be enlarged with the height of the engineering structure,and the tunnel is supposed to have a smaller PGA and lower dynamic earth pressure compared to bridges and embankments in strong earthquake zones crossing active faults.The findings contribute valuable insights for evaluating the dynamic response of various engineering structures crossing an active fault and provide an experimental reference for secure engineering design in the challenging conditions of the Sichuan-Tibet transportation corridor.

Effects of Some Management Practices on Electron Transport System (ETS) Activity in Paddy Soil

Electron transport system (ETS ) / dehydrogenase activity in a paddy field soil was measured under a variety of incubation conditions using the reduction of 2- (p-iodophenyl- 3- (p-nitrophenyl ) -5- phellyl tetrazolium chloride (INT) to iodonitrotetrazolium formazan (INTF). The results exhibited a high positive correlation between the ETS activity and the incubation temperature and soil moisture. Dehydrogenase/ETS activity displayed a negative correlation with insecticide concentrations, and the activity affected adversely as the concentration of the insecticide increased. The higher doses, 5 and 10 field rates (1 field rate ~ 1500 mL ha-1), of insecticide significantly inhibited ETS activity, while lower rates failed to produce any significant reducing effect. Inorganic N (as urea) of concentrations from 0 to 100 ug N g-1 soil showed a positive response to ETS activity. However, at concentrations of 200 and 400 ug N g-1, the activity was reduced significantly.

The relationship between transport-to-school habits and physical activity in a sample of New Zealand adolescents

Objectives:Adolescents using active transport(AT)to school have higher levels of physical activity(PA)compared with motorized transport(MT)users.This study compared school day and weekend day PA in adolescents using AT,MT,or combined AT and MT(AT + MT)to travel to school.Methods:Adolescents(n= 314;age:14.7±1.4 years;32.8% boys)from Dunedin(New Zealand)wore an accelerometer for 7 days and completed a self-reported survey regarding mode of transport to school(73 AT,56 AT + MT,and 185 MT).Data were analyzed using t tests,analysis of variance,and χ2 tests.Results:Although the proportion of adolescents meeting PA guidelines significantly differed among transport groups(AT,47.9%;AT + MT,46.4%;MT,33.5%;p=0.048;overall,39.2%),the observed differences were due mainly to girls.Compared with MT,AT and AT+MT engaged in more moderate-to-vigorous PA(MVPA)per day(AT:61.2 ± 23.2 min;AT+MT:59.6 ± 21.7 min;MT:52.5 ± 19.6 min;p = 0.004;p<0.001,adjusted for gender),per school day and before school.Immediately after school(15:00-16:00),AT engaged in significantly more MVPA compared with AT + MT and MT.No differences in MVPA between the groups were observed in the late afternoon/early evening period during school days or on weekend days.Conclusion:Compared with MT users,adolescent girls using AT or AT + MT accumulated more MVPA during school commute time.AT + MT to school is also a plausible way to increase adolescent girls’ PA when AT only is not feasible.

Differences in transportation and leisure physical activity by neighborhood design controlling for residential choice

Background:Cross-sectional studies provide useful insight about the associations between the built environment and physical activity(PA),particularly when reasons for neighborhood choice are considered.Our study analyzed the relationship between levels of weekly transportation and leisure PA among 3 neighborhood designs,statistically adjusting for sociodemographic characteristics and reasons for neighborhood choice.Methods:A stratified random sample of adults(age>20 years)living in Calgary(Canada)neighborhoods with different neighborhood designs(grid,warped-grid,and curvilinear)and socioeconomic status completed a self-administered questionnaire capturing PA,sociodemographic characteristics,and reasons for neighborhood choice(response rate=10.1%;n=1023).Generalized linear models estimated associations between neighborhood design and transportation and leisure PA outcomes(participation(any vs.none)and volume(metabolic equivalent:h/week)),adjusting for neighborhood socioeconomic status,sociodemographic characteristics(gender,age,ethnicity,education,household income,marital status,children,vehicle access,dog ownership,and injury),and reasons for neighborhood choice(e.g.,proximity and quality of recreational and utilitarian destinations,proximity to work,highway access,aesthetics,and sense of community).Results:Overall,854 participants had resided in their neighborhood for at least 12 months and provided complete data.Compared with those living in curvilinear neighborhoods,grid neighborhood participants had greater odds(p<0.05)of participating in any transportation walking(odds ratio(OR)=2.17),transportation and leisure cycling(OR=2.39 and OR=1.70),active transportation(OR=2.16),and high-intensity leisure PA(≥6 metabolic equivalent;OR=1.74),respectively.There were no neighborhood differences in the volume of any transportation or leisure PA undertaken.Adjustment for neighborhood selection had minimal impact on the statistical or practical importance of model estimates.Conclusion:Neighborhood design is associated with PA patterns in adults,independent of reasons for neighborhood choice and sociodemogranhic factors.

Changes in Antioxidant Activity of Alcalase-Hydrolyzed Soybean Hydrolysate under Simulated Gastrointestinal Digestion and Transepithelial Transport

Peptides from Alcalase-hydrolyzed soybean protein hydrolysate(SPH)may hold the potential as natural antioxidants.In addition,the effect of human gastrointestinal(GI)tract on peptide bioavailability needs to be explored.In this study,the impact of simulated GI digestion and transepithelial transport on various antioxidant properties of SPH were investigated.SPH displayed DPPH radical scavenging(IC50=4.22 mg/m L),ABTS·+radical scavenging(IC50=2.93 mg/m L),reducing power and metal ion-chelating activities(IC50=0.67 mg/m L).Furthermore,SPH significantly(P<0.05)inhibited the generation of intracellular reactive oxygen species(ROS)in Caco-2 cells.After simulated GI digestion,the antioxidant properties of SPH were enhanced,except for a decrease in ABTS·+radical scavenging activity.After transepithelial transport,the permeates maintained partial antioxidant activity and the LC-MS/MS data further identified the absorbed soybean peptides.These results suggest that SPH contains the antioxidant peptides that are potentially bioavailable and can be regarded as a promising source of functional food ingredients.

Physical Activity Calculation by Transport Modes Detection Using Fuzzy Logic

This research presents a methodology,to calculate the amount of physical activity during the transportation.It contains the following steps:(1)trip and activity detection(2)speed calculation(3)splitting trips into trip-leg(4)transportation mode detection and(5)physical activity calculation.The Global Positioning System is used to record the transport activities,either single mode or multimode.During the trip execution,the travel behaviour and the travel mode are also observed to obtain the physical activity levels.The physical activity levels are calculated by taking the ratio of the Total Energy Expenditure and the Basal Metabolic Rate.To obtain the results,an automated system is presented which calculates the speed and also detects the mode of each trip-leg.It also calculates the amount of physical activity.The obtained physical activity levels for the recorded 1750 trips are unit less and range from 1.10 to 2.00.By using the motorized transportation mode,the physical activity levels stay low and the subject failed to achieve the recommended health guideline.The minimum value for the moderate level of physical activity is 1.6.The requirement can be fully achieved when the transportation mode is active i.e.walking,cycling,and performed at moderate intensity level for at least 30 min a day.

Observation of saltation activity at Tazhong area in Taklimakan Desert,China

A two-year field observation of saltation activity was carried out at Tazhong area, the hinterland area of the Taklimakan Desert with highly frequent dust storms. From 1 September 2008 to 31 August 2010, a piezoelectric saltation sensor （Sensit） was used to continuously collect the data on saltation activity at a level sand surface. Analysis on the data suggests that saltation activity can occur at any time of the year when conditions are favorable; however, the necessary conditions are rarely satisfied in most time. In the daytime of spring or summer, saltation activity can persist even over a continuous one-hour-or-so period. It is found that, from 1 September 2008 to 31 August 2010, saltation activity accounts for more than 3% of the total yearly time, and it tends to peak in spring and summer months with strong winds. During winter months when winds are weak, however, it is often at a minimum. It seems that precipitation does not appear to be significant in reducing saltation activity in arid regions like Tazhong.

The built environment correlates of objectively measured physical activity in Norwegian adults:A cross-sectional study

Background: Built environments that are designed to provide accessible, attractive, and convenient locales promote regular physical activity(PA).Norway has great variability in its geographic, natural, and built environment features. Urban areas have well-developed built environment features, whereas the rural areas are less walkable and this may influence the mode of transport. In general, active transport is more common in urban centers. Further, public transportation is more developed in urban areas, whereas motorized transport may be more widespread in the rural areas. Despite this, in Sogn & Fjordane, a rural county in western Norway, high PA levels are frequently observed. Thus, the aims of this study were to(1) explore perceived built environment features and characterize their associations with objectively measured PA levels in Norwegian adults and(2) explore the differences in these correlates between Sogn & Fjordane and the rest of Norway.Methods: In this cross-sectional study, participants used questionnaires to rate perceptions of their built environments, and their PA was objectively measured for 7 consecutive days using the Acti Graph GT1 M accelerometer. There were 972 Norwegian adults who were included in the study. The average age was 46.9 ± 6.5 years and 43.8% of participants were men. Data were analyzed using multiple linear regression.Results: Total PA and moderate-to-vigorous physical activity(MVPA) were both associated with perceived walkability, the community perception score, and active transport for commuting(all p ≤ 0.004). We also observed geographic-area-specific associations: the community perception score was negatively associated with total PA and MVPA in the rest of Norway(p ≤ 0.012) but not in Sogn & Fjordane. Public transport for commuting was positively associated with MVPA in Sogn & Fjordane(p = 0.03) but not in the rest of Norway.Conclusion: Total PA level and MVPA were associated with built environment factors, such as perceptions of community, perceived walkability,and engaging in active transport for commuting. Geographic differences in the PA correlates were observed, and thus, locally customized environmental population approaches aimed at increasing PA levels may be essential complements to individual behavior and lifestyle strategies.Further, objective measures of Norwegian built environments, such as geographic information system data, and validated walk-and bike-scores would advance the field.

Transcriptional activation of glucose transporter 1 in orthodontic tooth movement-associated mechanical response

The interplay between mechanoresponses and a broad range of fundamental biological processes, such as cell cycle progression,growth and differentiation, has been extensively investigated. However, metabolic regulation in mechanobiology remains largely unexplored. Here, we identified glucose transporter 1(GLUT1)—the primary glucose transporter in various cells—as a novel mechanosensitive gene in orthodontic tooth movement(OTM). Using an in vivo rat OTM model, we demonstrated the specific induction of Glut1 proteins on the compressive side of a physically strained periodontal ligament. This transcriptional activation could be recapitulated in in vitro cultured human periodontal ligament cells(PDLCs), showing a time-and dose-dependent mechanoresponse. Importantly, application of GLUT1 specific inhibitor WZB117 greatly suppressed the efficiency of orthodontic tooth movement in a mouse OTM model, and this reduction was associated with a decline in osteoclastic activities. A mechanistic study suggested that GLUT1 inhibition affected the receptor activator for nuclear factor-κ B Ligand(RANKL)/osteoprotegerin(OPG)system by impairing compressive force-mediated RANKL upregulation. Consistently, pretreatment of PDLCs with WZB117 severely impeded the osteoclastic differentiation of co-cultured RAW264.7 cells. Further biochemical analysis indicated mutual regulation between GLUT1 and the MEK/ERK cascade to relay potential communication between glucose uptake and mechanical stress response. Together, these cross-species experiments revealed the transcriptional activation of GLUT1 as a novel and conserved linkage between metabolism and bone remodelling.

Effective transport of passive particles induced by chiral-active particles in microchannel

Transport of passive particles induced by chiral-active particles in microchannel is investigated by using the overdamped Langevin dynamics simulation in a two-dimensional model system. Due to the chirality of active particles and special structure of microchannel, effective ratchet transport of passive particles is achieved. Effective transport of passive particles depends on the width of microchannel（d）, the density（ρ）, and the angular velocity（ω） of chiral-active particles.There exist optimal parameters for d and ω at which the transport efficiency for passive particles takes its maximal value.This investigation can help us understand the necessity of active motion for living systems to maintain a number of vital processes such as materials transport inside cells and the foraging dynamics of mobile organisms.

Dipeptide transport: an active process with energy-and proton-dependence in the human intestinal cell line,Caco-2

Objective: To determine the active process on dipeptide transport with proton-and energy-dependence in Caco-2 cells.Methods: A human intestinal cell monolayer(Caco-2) was used as the in vitro model of human small intestine and cephalexin as the model substrate for dipeptide transporter(PepT1).Caco-2 cells grown on multiwell dishes(24 wells) and Transwell membrane filters were incubated in the culture medium. The transport and uptake experiments of cephalexin across apical membranes were then conducted with different temperature and different pH values.Uptake of cephalexin in Caco-2 cells gsown on multiple well dishes with addition of energy inhibitors(sodium azide,SA and 2,4-dinitrophenol,DNP) were then measured. Results: The accumulation of cephalexin into Caco-2 monolayers increased with the duration of culture.The uptake from the apical surface was markedly influenced by the pH of the apical medium,and the maximal uptake was achieved at pH 5.5;further acidification of the incubation medium may decrease transport of cephalexin despite an increase inward H+ gradient.Cephalexin uptake was linear over the concentration range when the cells were incubated at 4℃ while the uptake rate was enhanced and tended to be saturated as the cephalexin concentration increased when the cells were incubated at 37℃.The kinetic parameters for the cephalexin transport carrier were determined to be: Vmax of(22.173±1.9) nmol/min per mg protein,Km of(2.069±0.9)mol/L,the Kd was estimated to be(0.07±0.02) nmol/min per mg protein per mmol/L.Uptake of cephalexin was markedly inhibited by sodium azide(SA) and 2,4-dinitrophenol(DNP). Conclusion: Cephalexin was transported actively across Caco-2 cells,and the transport process was proton-and energy-dependent.In addition, Caco-2 cells taked up cephalexin by dipeptide transporters that closely resembled the transporters present in the intestine.Caco-2 cells represented an ideal cellular model for future studies of the dipeptide transporter.

Some substrates of P-glycoprotein targeting <i>β</i>-amyloid clearance by quantitative structure-activity relationship (QSAR)/membrane-interaction (MI)-QSAR analysis

The pathogenesis of Alzheimer’s disease (AD) putatively involves a compromised blood-brain barrier (BBB). In particular, the importance of brain-to-blood transport of brain-derived metabolites across the BBB has gained increasing attention as a potential mechanism in the pathogenesis of neurodegenerative disorders such as AD, which is characterized by the aberrant polymerization and accumulation of specific misfolded proteins, particularly β-amyloid (Aβ), a neuropathological hallmark of AD. P-glycoprotein (P-gp), a major component of the BBB, plays a role in the etiology of AD through Aβ clearance from the brain. Our QSAR models on a series of purine-type and propafenone-type substrates of P-gp showed that the interaction between P-gp and its modulators depended on Molar Refractivity, LogP, and Shape Attribute of drugs it transports. Meanwhile, another model on BBB partitioning of some compounds revealed that BBB partitioning relied upon the polar surface area, LogP, Balaban Index, the strength of a molecule combined with the membrane-water complex, and the changeability of the structure of a solute-membrane-water complex. The predictive model on BBB partitioning contributes to the discovery of some molecules through BBB as potential AD therapeutic drugs. Moreover, the interaction model of P-gp and modulators for treatment of multidrug resistance (MDR) indicates the discovery of some molecules to increase Aβ clearance from the brain and reduce Aβ brain accumulation by regulating BBB P-gp in the early stages of AD. The mechanism provides a new insight into the therapeutic strategy for AD.

刺葡萄VdERD6L15基因克隆及功能分析

【目的】探究VdERD6L15在刺葡萄果实生长发育中的功能,从湘刺1号中克隆VdERD6L15基因及其启动子,进行基因功能研究和启动子活性分析。【方法】克隆VdERD6L15基因CDS序列,并对CDS进行生物信息学分析;构建VdERD6L15表达载体,并通过瞬时转化烟草确定VdERD6L15基因编码蛋白的亚细胞定位;同时,通过在己糖缺陷型酵母菌株EBY.VW4000中异源表达VdERD6L15探究其功能;此外,通过启动子截短试验确定VdERD6L15启动子的核心区域。【结果】成功克隆刺葡萄VdERD6L15基因编码序列,该编码序列长1461 bp,可编码486个氨基酸,具有膜蛋白特征,属于单糖转运蛋白家族。亚细胞定位试验确认VdERD6L15蛋白主要定位于液泡膜上。通过在酵母菌株EBY.VW4000中进行异源表达,验证了VdERD6L15具有转运葡萄糖的能力。利用PlantCARE数据库对VdERD6L15启动子顺式作用元件进行分析,发现其主要包含光响应元件、干旱胁迫和激素响应元件。通过GUS染色分析,进一步确定候选基因VdERD6L15启动子的关键调控区域位于-500 bp到-1000 bp之间。【结论】VdERD6L15是一个定位在液泡膜上的糖转运蛋白,具有转运葡萄糖的功能;VdERD6L15启动子的核心元件位于ATG上游500~1000 bp之间。

水稻对恶苗病菌侵染响应的转录组分析

水稻是主要的粮食作物,而恶苗病的发生对水稻生产构成了巨大威胁,造成一些品种严重减产。转录组测序技术已逐渐应用到水稻恶苗病的品种抗性研究中,使用高抗和高感水稻品种,经接种、取样和测序分析,明确水稻恶苗病在转录水平上的抗性机制。利用Illumina NovaSeQ6000平台构建了12个真核普通转录组文库并测序,以|log 2(FoldChange)|≥1及p≤0.05为标准,筛选出抗病品种比较组合(KDI vSKDCK)1482个差异基因,感病品种比较组合(LJI vSLJCK)2293个差异基因。通过共表达韦恩图展示,抗病比较组合(KDI vSKDCK)差异基因和感病比较组合(LJI vSLJCK)差异基因共表达328个,其中抗病比较组合(KDI vSKDCK)差异基因中唯一表达1154个,感病比较组合(LJI vSLJCK)差异基因中唯一表达1965个。进一步通过共表达韦恩图展示,抗病比较组合(KDI vSKDCK)上调表达差异基因和感病比较组合(LJI vSLJCK)上调表达差异基因共表达31个,抗病比较组合(KDI vSKDCK)上调表达差异基因中唯一表达272个,感病比较组合(LJI vSLJCK)上调表达差异基因中唯一表达825个。将抗病比较组合(KDI vSKDCK)上调表达差异基因中唯一表达的272个基因进行GO功能富集分析后,得到264个GO Term,其中,显著富集GO Term有1个生物过程(BP)和6个分子功能(MF),均与病原菌感染响应的氧化应激反应(GO:0006979)、过氧化物酶活性(GO:0004601)、氧化还原酶活性和作用于作为受体的过氧化物(GO:0016684)、抗氧化活性(GO:0016209)有关,显示抗病品种水稻芽在恶苗病菌侵染时参与氧化应激反应生物过程基因显著上调表达,ATP酶活性显著增加,促进物质跨膜转运,有效提高了抗病性。

多因素协同的大型活动场馆周边路段速度预测

大型活动会引起举办场馆周边区域路网出现交通流短时骤增与消散,导致周边区域路网交通运行呈现偶发性与不确定性波动,而现有预测方法通常难以捕捉特殊事件下交通流受多维因素复杂影响及其演变机理。为充分挖掘路段速度的时间序列和影响因素特征,揭示速度预测中不同影响特征间的耦合作用机理,提出了一种结合可解释机器学习与长短时记忆网络的速度预测模型(MC-LSTM)。结合大型活动的特点构建影响因素集,采用XGBoost算法评价活动规模、性质等因素特征对场馆周边路段速度的影响相对重要度,量化多元因素对场馆周边路网运行状态的协同效用,融合LSTM网络,考虑交通状态的时间依赖关系,捕获不同历史时期的时间相关性,实现对活动期间场馆周边路段速度的精确预测。以北京市连续6个月的大型活动期间周边路网为例进行模型验证,结果表明:所构建的MC-LSTM模型的预测精度可达94.5%以上,优于考虑多因素协同的XGBoost模型、只考虑单因素特征的LSTM模型及未考虑外部特征的LSTM模型,证明该研究所提出的模型有效性与稳定性更优,可为大型活动场馆周边路网交通组织优化和制定针对性交通管控与保障措施提供定量化的决策依据。

不同粒径零价铁对微氧脱氮系统的影响

构建了部分硝化反硝化厌氧氨氧化(SNAD)微氧体系,并定期向体系内投加120 mg不同粒径的零价铁(ZVI),从反应器运行情况、微生物性能以及群落结构来探究不同粒径ZVI对微氧系统的影响。研究结果表明,在50 nm粒径ZVI(50 nZVI)的介导下,系统的TIN去除率最终稳定在83.591%,电子传递活性(ETSA)是接种污泥的1.48倍,均高于其他粒径ZVI的影响。越小粒径ZVI越能促进胞外聚合物的产生,有利于活性污泥结构稳定。这都源于粒径越小的ZVI更容易被微生物吸附、利用。微生物群落结构与功能分析结果表明,在粒径越小的ZVI介导下的微生物群落多样性越高,群落结构也越复杂。ZVI介导会促进对氧需求不敏感的微生物的富集,样品中主要检测出Candidatus_Brocadia和Candidatus_Kuenenia两种厌氧氨氧化菌(AnAOB),且在50 nZVI影响下丰度最高,分别为4.650%和0.692%。nZVI介导下,AnAOB与Gemmobacter和norank_f_Comamonadaceae两种兼性厌氧型反硝化菌共同作用构成SNAD的脱氮途径。而在mZVI介导下,兼性厌氧型反硝化为主要脱氮途径。

浅埋综采工作面运输巷主动式超前支护研究

针对浅埋综采工作面运输巷采用单体支柱超前加强支护工作面推采速度与支护速度不协调、工人劳动强度和安全隐患大、难以实现超前区域少人化等问题,以榆家梁煤矿52305工作面为工程背景,采用现场实测、数值模拟和理论分析相结合的方法,实测了单体超前加强支护条件下的运输巷矿压显现规律,对比分析了单体加强支护和锚杆(索)主动式加强支护两种情况下的巷道围岩安全稳定性,并通过理论分析计算了运输巷支护参数,校验了现场支护的适应性及安全性。研究结果表明:52305工作面运输巷围岩属于较稳定型,现场单体超前加强支护条件下,锚杆(索)承载均在额定载荷的85%以内,两帮应力分布基本对称,围岩移近量和松动圈很小,围岩稳定性较好,现场超前支护段支护强度偏富余。采动支承压力影响段,单体支柱主要对顶板0.6 m范围内的局部岩层具有加强支撑作用,远小于锚杆和锚索支护作用范围和强度。取消单体支护后,运输巷围岩依然能够保持安全稳定。在榆家梁煤矿52305工作面运输巷超前加强支护段进行了取消单体支护工程试验,验证了研究结论的可靠性。

管花肉苁蓉提取物的工艺优化及其活性评价

该研究旨在利用响应面法优化管花肉苁蓉活性成分的提取工艺,并进一步对其抗氧化与美白活性进行研究。通过超声-微波法提取管花肉苁蓉中活性成分,以提取物中松果菊苷为指标成分,结合Box-Behnken响应面法优化提取工艺,得到提取物后通过测试DPPH自由基、ABTS阳离子自由基清除能力、总还原力对其进行体外抗氧化活性评价;通过CCK-8法、流式法检测小鼠黑色素瘤细胞(B16细胞)相关指标并评价其体外美白活性。结果表明,最优提取工艺条件为料液比1:16(g:mL),乙醇体积分数70%,超声功率160 W,超声时间6 min,该条件下提取物中松果菊苷含量为8.09%;管花肉苁蓉提取物在2 mg/mL下自由基清除能力与抗坏血酸相当,有较好的总还原能力;当管花肉苁蓉提取物质量浓度为50 mg/mL时,B16细胞内黑色素含量降至58.12%,酪氨酸活性的抑制率达到32.10%,当提取物质量浓度为100 mg/mL时,黑素小体转运量降至12.77%,能显著抑制酪氨酸酶活性、黑色素的生成及黑素小体转运。管花肉苁蓉提取物表现出显著的体外抗氧化能力以及较好的美白效果,作为天然抗氧化、美白原料具有潜在开发价值。

基于固定/PTZ摄像机系统的开阔水域小目标船舶主动式跟踪方法

仅依靠当前的闭路电视(closed-circuit television,CCTV)系统,往往难以主动跟踪并拍摄内河船舶清晰的图像。针对上述问题,研究了基于固定/平移-倾斜-对焦(pan-tilt-zoom,PTZ)摄像机系统的开阔水域小目标船舶主动式跟踪方法。采用基于虚拟四边形的三层联合标定模型对固定摄像机和PTZ摄像机进行联合标定,将虚拟四边形内的图像坐标与PTZ摄像机的平移角和倾斜角一一对应;引入虚拟四边形的概念,有效过滤虚拟四边形外目标的干扰,提高小目标船舶的检测准确率;利用透视n点(perspective-n-point, PnP)问题算法和虚拟四边形顶点的图像坐标,得到图像坐标与世界坐标间的映射关系,再利用Pan-Tilt-Height(PTH)模型将虚拟四边形中目标的世界坐标转化为PTH坐标;在小目标跟踪过程中,通过连续检测虚拟四边形中船舶边框质心的图像坐标,即可计算得到PTZ摄像机的平移角与倾斜角,从而实现实时主动跟踪的目的,并尽最大限度的保持船舶目标处于PTZ摄像机图像的中心位置。选取湖北省孝感市春晖湖和武汉市汉江中法桥段这2处真实场景,进行可靠性和有效性验证,实验结果表明:①利用改进的目标检测方法对固定摄像机图像中的船舶进行检测,F1-Score分别为96.82%和97.62%;②利用研究的主动式跟踪方法跟踪运动船舶时,PTZ摄像机的跟踪失败率为4.63%。本文研究的主动式跟踪方法的跟踪速率可以达到18.55 fps。

鞣花酸对下石节长焰煤氧化自燃的阻化影响研究

为考察鞣花酸(EA)对煤氧化自燃过程的影响,首先将EA与陕西铜川下石节煤矿的长焰煤以2%、4%、6%、8%和10%的质量比均匀混合进行试验;然后采用显微红外光谱试验和激光导热试验研究各个样品的活性官能团含量情况和热输运特性,通过评价煤氧化自燃抑制效果,确定最优质量比为8%;最后利用煤自燃程序升温试验对比4种阻化剂对煤氧化自燃气体释放的影响情况,进一步确定EA对煤氧化自燃的阻化程度。结果表明:EA处理煤(EA-tc)中-CH_(3)、-CH_(2)、-OH和-C=O-的峰面积相较于原煤(RC)均减少,但C-O的峰面积增加;在相同煤温下,RC的热扩散系数和导热系数高于EA-tc,其比热容低于EA-tc,且8%EA对RC低温氧化过程的热扩散系数、比热容和导热系数的平均抑制率分别为20.8%、9.8%和13.1%;相比于RC,8%EA-tc的CO释放量在170℃时降低52.3%,且EA对煤氧化自燃的阻化率在30~170℃内保持在50.5%~72.5%,说明EA对煤氧化自燃的阻化效果比其他3种阻化剂更好。