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小麦叶片水势测定值的取样误差

麦类作物学报 1988年第5期 28-31页

作者： r.c.johnson 郭平仲

利用叶片切割湿度计可迅速取得水势测定值样本。不过,如果切面面积对样本体积的比率高,则相当小的叶样(0.24平方厘米)也可能导致蒸腾失水,从而造成测定误差。在生长室中用不同水分胁迫水平下的普通小麦植株所进行的试验表明:由平均7平... 详细信息

利用叶片切割湿度计可迅速取得水势测定值样本。不过,如果切面面积对样本体积的比率高,则相当小的叶样(0.24平方厘米)也可能导致蒸腾失水,从而造成测定误差。在生长室中用不同水分胁迫水平下的普通小麦植株所进行的试验表明:由平均7平方厘米的叶片(切面对体积的比率很低)测得的叶水势值接近于由0.24平方厘米切面得到的数值。方法间的一致性可能与湿度计腔内切面的迅速封闭有关(通长在切后3秒内封闭)。利用叶片切割湿度计测定了旗叶水势,并估算对照对胁迫条件下小麦的取样误差和试验误差。估算这些数值的目的在于确定为了获得小麦水势测定值的特定统计精确度所需要的样本数和重复数。

关键词：湿度计重复数热工仪表水势样本数测定值观测值误差方差置信区间置信距

硬粒红穗冬小麦两种冠层结构的表面光合作用与土壤水分蒸腾蒸发总量和光线的穿透能力(摘要)

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甘肃农业科技 1982年第12期 31-31,9页

作者： r.c.johnson 李守谦

在时间和空间上非常易变的作物冠层结构影响着光线的拦截、表面光合作用和土壤水分蒸腾蒸发总量。作者的目的在于阐述在大田环境条件下,两种行距冬小麦的表面光合作用、土壤水分蒸腾蒸发总量与光线的拦截、叶面积指数、温度和产量的关... 详细信息

在时间和空间上非常易变的作物冠层结构影响着光线的拦截、表面光合作用和土壤水分蒸腾蒸发总量。作者的目的在于阐述在大田环境条件下,两种行距冬小麦的表面光合作用、土壤水分蒸腾蒸发总量与光线的拦截、叶面积指数、温度和产量的关系。本试验采用“Wanser”冬麦品种,20厘米（140公斤/公顷）和40厘米行距（70公斤/公顷）两个处理。用两个占地面积0.74平方米的铝结构轻便同化室和cO2气体分析仪对两个处理入口处和出口处的cO2浓度和水分含量进行了测定。以确定不同处理的表面光合作用和土壤水

关键词：土壤水分土壤成分冬小麦冬麦光线

密歇根地区Ishpeming太古宙绿岩带中矿脉的铅同位素研究

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贵金属地质 1999年第3期8卷 188-192页

作者： T.J.Bornhorst r.I.Thorpe r.c.johnson Michigan Technological University USAGeological Survey of CanadaTrans Superier ResourcesIncMichiganUSA

１　引　言含有石英＋硫化物±碳酸盐矿物组合的矿脉在Ｉｓｈｐｅｍｉｎｇ太古宙绿岩带中普遍存在（见图１）．Ｒｏｐｅｓ金矿的这种矿脉是美国已知的产于太古宙岩石中的唯一有意义的脉状金矿床．Ｒｏｐｅｓ金矿矿脉及伴生的蚀变岩含金... 详细信息

１　引　言含有石英＋硫化物±碳酸盐矿物组合的矿脉在Ｉｓｈｐｅｍｉｎｇ太古宙绿岩带中普遍存在（见图１）．Ｒｏｐｅｓ金矿的这种矿脉是美国已知的产于太古宙岩石中的唯一有意义的脉状金矿床．Ｒｏｐｅｓ金矿矿脉及伴生的蚀变岩含金约１０５００ｋｇ，其Ａｕ／Ａｇ比值约为０．７．有两度开采史，分别为１８８２～１８９７年和１９８６～１９８９年．产于Ｉｓｈｐｅｍｉｎｇ绿岩带的Ｒｏｐｅｓ矿床和其他小型矿床、矿点中的矿脉为后生成因并受断裂和剪切带控制．矿脉的年龄界定程度很差．本研究的目的，就是以矿脉的方铅矿铅同位素组成为基础，界定矿脉的年龄．图１　苏必利尔湖地区Ｉｓｈｐｅｍｉｎｇ绿岩带地质略图１—加拿大与美国之间的国界

关键词：太古宙绿岩带矿脉铅同位素金矿床

comparison of a Spectral Bin and Two Multi-Moment Bulk Microphysics Schemes for Supercell Simulation:Investigation into Key Processes responsible for Hydrometeor Distributions and Precipitation

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Advances in Atmospheric Sciences 2024年第5期41卷 784-800页

作者： Marcus johnson Ming XUE Youngsun JUNG center for Analysis and Prediction of Storms University of OklahomaNormanOK 73072USA School of Meteorology University of OklahomaNormanOK 73072USA Office of Science and Technology Integration National Weather ServiceSilver SpringMD 20910USA

There are more uncertainties with ice hydrometeor representations and related processes than liquid hydrometeors within microphysics parameterization(MP)schemes because of their complicated geometries and physical *** supercell simulations are produced using the WrF model coupled with“full”Hebrew University spectral bin MP(HU-SBM),and NSSL and Thompson bulk MP(BMP)***-SBM downdrafts are typically weaker than those of the NSSL and Thompson simulations,accompanied by less rain ***-SBM produces more cloud ice(plates),graupel,and hail than the BMPs,yet precipitates less at the *** limiting mass bins(and subsequently,particle size)of rimed ice in HU-SBM and slower rimed ice fall speeds lead to smaller melting-level net rimed ice fluxes than those of the *** from plates in HU-SBM,together with snow–graupel collisions,leads to a greater snow contribution to rain than those of the *** HU-SBM’s fall speeds using the formulations of the BMPs after aggregating the discrete bin values to mass mixing ratios and total number concentrations increases net rain and rimed ice ***,they are smaller in magnitude than bulk rain,NSSL hail,and Thompson graupel net fluxes near the ***,the melting-layer net rimed ice fluxes are reduced when the fall speeds for the NSSL and Thompson simulations are calculated using HU-SBM fall speed formulations after discretizing the bulk particle size distributions(PSDs)into spectral *** results highlight precipitation sensitivity to storm dynamics,fall speed,hydrometeor evolution governed by process rates,and MP PSD design.

关键词： precipitation spectral bin microphysics bulk microphysics parameterization microphysics processes WrF model supercell storm

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土壤含水量对冬小麦产量的影响

麦类作物学报 1984年第6期 36-36页

作者： r.c.johnson 何锦豪

在半干旱地区栽培小麦,土壤含水量对产量的影响较大。据报道,小麦由于缺水而减产的程度,因缺水时所处的生育期不同而异,开花期前缺水比开花期后缺水减产幅度大。为了研究土壤含水量对田间冬小麦产量的影响,笔者等作了如下试验,并对构成... 详细信息

在半干旱地区栽培小麦,土壤含水量对产量的影响较大。据报道,小麦由于缺水而减产的程度,因缺水时所处的生育期不同而异,开花期前缺水比开花期后缺水减产幅度大。为了研究土壤含水量对田间冬小麦产量的影响,笔者等作了如下试验,并对构成产量的诸因素作了分析。

关键词：冬小麦冬麦土壤含水量土壤墒情产量

Gouty destruction of a patellar tendon reconstruction and novel revision reconstruction technique: A case report

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World Journal of Orthopedics 2024年第7期15卷 675-682页

作者： carl c Edge Jonathan Widmeyer Omar Protzuk Maya johnson robert O’connell Department of Orthopaedic Surgery Division of Sports MedicineVirginia Commonwealth University Health SystemRichmondVA 23298-0153United States Division of Sports Medicine OrthowestCarroltonGA 30117United States

BAcKGrOUND Gout is a disease characterized by hyperuricemia,and resultant deposition of uric acid crystals in *** typically manifested as intraarticular crystals or tophi,gout can also cause pathology at *** deposition within tendinous structures put them at risk for traumatic and degenerative ***,allografts can also be at risk of rupture in the setting of severe *** present the case of a 56-year-old female with severe gouty disease who sustained a re-rupture of a patellar tendon allograft *** SUMMArY A 56-year-old female presented to clinic after feeling her left knee pop and collapse beneath her while descending *** had a history of tophaceous gout and left patellar tendon rupture with reconstruction and multiple revisions over the course of 19 *** patient presented with pain and extensor lag.A magnetic resonance image demonstrated a ruptured patellar tendon allograft reconstruction and avulsion fracture at the tibial *** patient was treated with a novel intervention of Achilles allograft with bone block in a unique configuration with a dermal allograft incorporated into the *** was made non-weight bearing in the operative extremity in extension for the first four weeks postoperatively and was then progressed to active flexion over the course of eight *** twelve weeks,she was able to fully extend her operative knee and at five months she was resuming her normal activities and *** Failed patellar tendon reconstruction due to gouty infiltration is treated with dermal allograft augmented Achilles tendon reconstruction with bone block.

关键词： Gout Patella reconstruction Dermal allograft revision case report

Influence of B4c and ZrB2 reinforcements on microstructural,mechanical and wear behaviour of AA 2014 aluminium matrix hybrid composites

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Defence Technology（防务技术） 2024年第10期40卷 242-254页

作者： ramesh Babu r rajendran c Saiyathibrahim A rajkumar Velu Department of Mechanical Engineering Karpagam Institute of TechnologyCoimbatore 641105India Department of Mechanical Engineering Sri Krishna College of Engineering and TechnologyCoimbatore 641008India Department of Mechanical Engineering Indian Institute of Technology JammuJammu and Kashmir 181221India

considering their affordability and high strength-to-weight ratio,lightweight aluminium alloys are the subject of intensive research aimed at improving their properties for use in the aerospace *** research effort aims to develop novel hybrid composites based on AA 2014 alloy through the use of liquid metallurgy stir casting to reinforce dual ceramic particles of Zirconium Diboride(ZrB_(2))and Boron carbide(B4c).The weight percentage(wt%)of ZrB_(2) was varied(0,5,10,and 15),while a constant 5 wt%of B4c was maintained during this *** as-cast samples have been assessed using an Optical Microscope(OM)and a Scanning Electron Microscope(SEM)with Energy Dispersive Spectroscopy(EDS).The properties such as hardness,tensile strength,and wear characteristics of stir cast specimens were assessed to examine the impact of varying weight percentages of reinforcements in AA 2014 *** particular,dry sliding wear behaviour was evaluated considering varied loads using a pin-on-disc *** the weight%of ZrB_(2) grew and B4c was incorporated,hybrid composites showed higher hardness,tensile strength,and wear ***,the incorporation of a cumulative reinforcement consisting of 15 wt%ZrB_(2) and 5 wt%B4c resulted in a significant 31.86%increase in hardness and a 44.1%increase in tensile strength compared to AA 2014 *** addition,it has been detected that wear resistance of hybrid composite pin(containing 20 wt%cumulative reinforcement)is higher than that of other stir cast wear test pins during the whole range of applied *** surfaces of tensile specimens showed ductile fracture in the AA 2014 matrix and mixed mode for hybrid *** surfaces obtained employing higher applied load indicated abrasive wear with little plastic deformation for hybrid composites and dominant adhesive wear for matrix ***,the superior mechanical and tribological performance of hybrid composites can be attributed to dual reinforcement pa

关键词： AA 2014 alloy Stir casting Hybrid composite Hardness Tensile strength Specific wear rate

Mantle avalanches in a Venus-like stagnant lid planet

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Earth and Planetary Physics 2024年第5期8卷 686-702页

作者： Madeleine c.Kerr Dave r.Stegman Institute of Geophysics and Planetary Physics Scripps Institution of Oceanography University of California

Stagnant lid planets are characterized by a globe-encircling, conducting lid that is thick and strong, which leads to reduced global surface heat flows. consequently, the mantles of such planets can have warmer interiors than Earth, and interestingly, a pyrolitic mantle composition under warmer conditions is predicted to have a distinctly different mantle transition zone compared to the present-day Earth(Hirose, 2002; Stixrude and Lithgow-Bertelloni, 2011; Ichikawa et al., 2014; Dannberg et al, 2022). Instead of olivine primarily transforming into its higher-pressure polymorphs such as wadsleyite and then ringwoodite, at pressures corresponding to410 km and 520 km depth in Earth, respectively, it instead transforms into a mineral assemblage of wadsleyite, majorite, and ferropericlase(WMF), and then to majorite + ferropericlase(MF), before finally transforming into bridgmanite at pressures corresponding to 660 km depth in Earth(Stixrude and Lithgow-Bertelloni, 2011; Ichikawa et al., 2014). convective motions in stagnant lid planets are dominated by small-scale instabilities(cold drips) forming within the mobile rheological sublayer under the rigid lid. Using ASPEcT and a thermodynamic model of a pyrolitic mantle composition generated by HeFESTo, we show that under certain conditions, the small drips can pond atop the WMF-MF mineral phase transition. The barrier to convective flow arises from the WMF mineral phase assemblage having an effective negative thermal expansivity(Stixrude and Lithgow-Bertelloni, 2022). Although large-scale downwellings that typically occur within mobile lid planets are able to pass through the WMF zone without difficulty(Dannberg et al., 2022; Li rP et al.,2024), the smaller and less negatively buoyant nature of downwelling drips in stagnant lid planets are more susceptible to these effects,which leads to an ephemeral layering of the mantle. Our numerical models show that in stagnant lid planets with mantle potential temperatures that exceed

关键词： Venus mantle avalanches numerical modelling phase transitions

Iso-propyl caprylate and iso-propyl linolenate synthetic fluids as novel alternatives in deep-water drilling operations:critical fluid properties and aerobic biodegradability assessments

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Petroleum 2024年第2期10卷 254-264页

作者： Adewale johnson Folayan Adewale Dosunmu Aleruchi Boniface Oriji Department of Petroleum and Gas Engineering University of Port HarcourtNigeria Professor of Petroleum and Gas Engineering University of Port HarcourtNigeria

Present drilling fluids for deep water wells have severe degenerative effect on the environment with high operational and disposal ***,making them less desirable in recent *** synthetic drilling fluid provides a novel environmentally friendly alternative but conventional ester-based drilling fluids exhibit high viscosities in deep-water wells causing excessive equivalent circulating density(EcD)and increased risk of lost circulation owing to narrow mud density *** study experimentally investigates the critical fluid properties and aerobic biodegradability potentials of two newly developed deep-water synthetic ester drilling fluids namely:iso-propyl caprylate(cOIPE)and iso-propyl linolenate(LOIPE)synthetic fluids and their comparison with synthetic-paraffin(SP-SBF)and isomerized-olefin(IOSBF)synthetic hydrocarbon *** esters of iso-propyl caprylate and iso-propyl linolenate were produced from the isolation of ester mixtures that were obtained from the homogeneous catalytic transesterification of coconut and linseed plant oil biomass *** cOIPE was isolated from the coconut oil iso-propyl ester mixture by low-pressure fractional distillation *** fractional distillation and crystallization were used to isolate the LOIPE ester from the linseed oil iso-propyl ester ***,the aerobic biodegradation investigation was conducted by a modified oxygen consumption respirometry *** Gc-MS analysis of the cOIPE and LOIPE showed that the former contains essentially of lower saturated carbon compounds(c8).Whereas the latter contains higher molecular weight and unsaturated carbon compounds(c18+).The cOIPE and LOIPE kinematic viscosity values are in good agreement with that of the reference synthetic hydrocarbon fluid samples(SP-SBF and IO-SBF).Although,the cOIPE synthetic ester has lower viscosity value owing to the presence of shorter chain and saturated carbon atoms(c8 esters).Similarly,the linolenic oil iso

关键词： Aerobic biodegradation critical fluid properties Deep-water wells Esters'isolation:isomerized-olefin(IO-SBF) Iso-propyl caprylate(cOIPE) Iso-propyl linolenate(LOIPE) respirometry technique Synthetic-paraffin(SP-SBF)