灌浆压力测量误差的正交试验分析

灌浆规范中的灌浆压力是作用在灌浆岩体上的孔内灌浆压力。由于工艺的约束,现行灌浆监控过程常用孔口压力表示孔内灌浆压力,造成了灌浆压力的测量误差。针对非循环灌浆工艺,通过建立流体管道流动模型开展数值计算,采用多因素多水平正交法探究灌浆压力误差受浆液配比、浆液流速、灌浆孔深的相对影响,并采用统计法来分析不同工况下的显著影响因素。研究结果表明：灌浆压力较小时,灌浆压力误差普遍较大;若此时灌浆孔深且流速较大时,灌浆压力的测量误差则会超过灌浆压力仪表0.5%的精度要求,须进行误差补偿。其次,极差分析结果表明灌浆孔深是造成测量误差的主要因素,灌浆流速是第二个主要因素。而综合所有试验结果,浆液流速和灌浆孔深接近时,浆液配比越小,绝对偏差越大。结合上述正交试验和数值模型获取了不同工况下孔内灌浆压力值。     

水稻甬优12不同产量群体的株型特征

以籼粳交超级稻甬优12为试材,比较研究高产(10.5~12.0 t hm^-2)、更高产(12.0~13.5 t hm^-2)、超高产( >13.5 t hm^-2) 3个群体的株型特征。结果表明,穗长、穗粒数、一次和二次枝梗数,超高产群体分别为21.56、356.34、20.46和73.98 (两年平均值),均高于对应的高产和更高产群体,但一次和二次枝梗的结实率略微降低。超高产群体上部三叶的长、宽以及卷曲率高,倒一、二、三叶的卷曲率分别为1.84、1.47、1.26,叶基角和披垂度小,抽穗后的主茎绿叶数多。超高产群体株高为143.50 cm,分别较更高产、高产群体高1.98%和3.83%,上部第一、二、三节间长度增加,穗长加穗下节间长占株高比例、穗下节间占秆长比例高,分别为39.84%和37.75%;基部第一、二、三节间长度缩短,茎秆粗度和茎壁厚度增加,茎、鞘干物重以及K、Si含量高,提高了基部节间的抗折力同时降低了倒伏指数。     

种植密度对贵州春玉米茎秆抗倒伏性能及籽粒产量的影响

为了明确密植条件下春玉米茎秆特性和产量的变化及其相互关系,为贵州春玉米密植高产提供理论依据和实践指导。以贵州广泛种植的玉米品种先玉1171和新中玉801为材料,设置3.0、4.5、6.0、7.5、9.0和10.5万株hm-26个密度,于2018—2019年开展田间试验,研究种植密度对春玉米茎秆形态特征和力学特性、空秆率、倒伏率和产量的影响。结果表明:(1)春玉米株高和穗位高随密度增加先增高后降低;增密后第3节长增幅最大,第3节单位茎长干重、穿刺强度和抗折力,第7节茎粗、干重和横截面积下降幅度最大;密度对茎秆横截面扁率影响不显著。品种之间比较,先玉1171节间长,第3、5节的节间干重和第3节穿刺强度显著高于新中玉801,第7节干重、节间粗、单位茎长干重、节间横截面积、横截面扁率和抗折力显著低于新中玉801。(2)倒伏率和空秆率随密度增加而增大,增密后先玉1171倒伏率显著高于新中玉801,空秆率显著低于新中玉801。(3)产量随密度增加先增加后降低,先玉1171和新中玉801分别在9.3万株hm^-2和8.6万株hm^-2时产量最高。增密后先玉1171比新中玉801增产10.28%,有效穗数和穗粒数更高。(4)相关和多元回归分析表明,株高、穗位高与倒伏率显著正相关,节间粗和单位茎长干物质对玉米茎秆抗折力的正向影响显著。产量与茎秆性状密切相关,株高对产量的正向影响最大。可见,不同春玉米茎秆抗倒伏性能和籽粒产量对密度的响应有差异,新中玉801增密后茎秆节间短而粗,单位茎长干重较大,抗倒伏能力较强。而先玉1171由于在高密度下空秆率比新中玉801低,有较高的有效穗数和穗粒数,因此高密度下产量更高。综合考虑茎秆性状和产量,先玉1171和新中玉801在贵州适宜密度分别为9.0万株hm^-2和8.5万株hm^-2。     

海南省不同区域农业可持续发展评价研究

为准确把握海南省典型地区农业可持续发展状况,诊断识别各地区农业可持续发展的障碍性因子,通过基于欧氏距离的农业可持续发展评价理论对海南省农业可持续发展情况进行评价。选取海南省海口市、三亚市和琼中县的2000~2015年数据展开分析,结果表明：(1)海口市农业可持续发展指数总体变化呈下降趋势,可持续发展指数介于0.44~0.52;三亚市农业可持续发展指数呈现上升趋势,可持续发展指数处于0.31~0.59之间;琼中县农业可持续发展指数呈上升趋势,但2007年之后可持续发展指数呈波动发展,可持续发展指数处于0.27~0.31之间。三个地区均属于低可持续发展状态。(2)肥料、农药、农村灾害、农技和农村劳力等指标是海南省低可持续发展的主要原因。各地区应该因地制宜,制定符合自身情况的政策和方针。(3)评价结果较为准确地反映了海南省农业系统情况。在上述研究结果基础上,研究其时空变化特征,提出未来推动该地区农业可持续发展举措,以期为海南省农业可持续发展提供参考。     

Stress Distribution in Fixed Anchor Length of Compression Type Anchor in Soft Rock Mass

To study stress distribution in fixed anchor length of compression type rock anchor cable, field test was carried out. Strain sensors were placed in the grout paste in fixed anchor length with certain interval. Axial and radial strains of the grout were noted by test. Shear stress distribution curve along the fixed anchor length was obtained by stress-strain relationship and static equilibrium analysis. Analysis results prove that maximal shear stress on the interface can achieve upper level and move forward when the load increases; the transmission length is short; shear stress transfers forward; and three dimensional state is obvious around capacity plates in soft rock mass.     

Genetic and Phenotypic Association between Yield Components in Hybrid Sorghum (Sorghum bicolor (L.) Moench) populations

Summary The magnitude of genetic expression and associations among traits are important for the prediction of response to selection in diverse environments and provide the basis for planning and evaluating breeding programs. In this regard, a cross classification mating design was used to produce hybrid sorghum populations, which were evaluated in a randomized completed block design with three replications at four environments in Northern Cameroon. Data on grain yield, days to anthesis, plant height, inflorescence length, threshing percentage and seed mass were collected and subjected to statistical genetic analyses. Significant genotype × environment interaction effects were observed for all traits. Genetic variance was essentially attributed to additive gene effects, with dominance variance for grain yield being negligible. However, the reverse was observed for threshability. Genetic variance components were much higher for plant height and grain yield than for days to anthesis, seed mass and threshability. Heritability estimates for plant height and inflorescence length were high (77 and 54 percent respectively) while the estimates for grain yield and threshability were low (14 and 5 percent respectively). Grain yield had positive genotypic correlation with most of the traits. Days to anthesis were negatively correlated with vegetative and reproductive traits. These results suggest that improvement of days to anthesis, plant height, and inflorescence length should be faster because of higher heritabilities and greater phenotypic variation. However, selection for earliness and reduced plant height would not be possible without hampering grain yield. Selecting for yield primary components namely inflorescence length and seed weight would be effective for increasing production. In addition, optimizing agronomic practices and improved experimental design would increase the selection efficiencies.     

Failure Mechanism and Mechanical Properties of CFRP Strengthened Super-servicing Reinforced Concrete Poles

Super-servicing reinforced concrete poles (RCP) which come from a road section in a power grid, including six pole shafts and six specimens with a mid-span steel joint, were selected as samples to conduct a flexural strength test, in which three shafts and three poles with steel joint in the middle span were strengthened by CFRP in the longitudinal direction. The mechanical behavior and failure mechanism under different CFRP layers pasted were comparatively studied. Based on the measured test data, the calculation methods of strength and stiffness were investigated, and the mathematical expression of stiffness degradation mechanism was proposed. The result shows that the final failure mode of CFRP strengthened poles is the local bond failure between CFRP material and the external concrete, and the longitudinal CFRP is snapped. The process of damage is rapid and brittleness. The mean strain of cross-section is in accord with the assumption of plane cross-section. The strength degradation of shaft specimens without strengthened is throughly serious. As for the strengthened poles, the bearing capacity and stiffness under each forcing stage are improved with different levels. The damage of strengthened specimens develops faster and more intensive than that of none-strengthened ones. When multi-aspects are synthetically considered, there is a suggestion that double layers of CFRP should be pasted along the longitudinal in the joint of the site within a certain distance, and the single layer of CFRP should be adopted in the shaft.     

不同氮利用效率基因型水稻茎秆特性比较

选用低产氮低效型、高产氮中效型和高产氮高效型具有代表性的6个粳稻品种,在各基因型各自最适氮素水平下,研究了茎秆力学特性、物理特性和化学成分含量的差异及其与氮效率的关系。结果表明：(1)较之低产类型品种,高产类型品种茎秆基部N₁节间变短、N₆节间变长,株高有所增加;茎粗、茎壁厚、茎鞘干重均极显著增加;茎鞘的K、Si含量极显著增加,N含量显著降低。由于茎秆物理性状的改善及化学成分的差异导致茎秆综合抗折力明显提高,倒伏指数降低。(2)同为高生产力类型品种,因氮效率的差异茎秆形态生理特征表现不同。较之高产氮中效类型,高产氮高效类型水稻品种茎秆N₄、N₅节间变长;茎秆粗度略有降低,但茎壁厚增加,表现茎秆干重增加,充实度加强;茎鞘的K含量无明显变化,但Si含量显著降低,N含量也呈降低趋势。对于高产品种,适当增加N₄、N₅节间长度以改善叶片配置,适当降低茎粗而提高壁厚和充实度以保证茎秆抗折力和输导能力,适当降低茎鞘Si含量以促进氮素的转移,有利于进一步提高氮肥利用率。     

杂交水稻茎秆形态学优势性状与抗倒伏能力研究

以茎杆粗壮型海南野生稻S和安仁籼稻、R199、武育粳、R215及其配制组合F1为材料，研究杂交水稻茎秆形态学优势性状与抗倒伏能力的关系，结果表明：海南野生稻s的茎秆基部抗折断能力较强，基部节间结构较优，株高和茎杆长度合理，基部伸长节间较短、充实度高，是一个茎秆物理性状良好、抗倒伏能力强的光温敏核不育系材料；以海南野生稻S为母本与安仁籼稻、武育粳、R199和R215所配制的组合F1茎秆基部抗折断能力和充实度、基部伸长节间粗度、横切面面积和茎壁厚度等性状明显优于其父本并袁现出一定的平均优势或超亲优势，株高较父本明显增加，但基部伸长节间长度较父本短，具备抗倒伏性较强的生物学基础。     

Study on mechanical behaviors of interface with cemented soil slurry between gravel and concrete by simple shear tests

The mechanical behaviors of the interface between coarse-grained soil and concrete are investigated by simple shear tests under conditions of cemented soil slurry (clay mixed with cement grout). The results show that the relation curve between shear stress and shear strain appears stress-strain softening and shear dilatation is significant. The point of peak strength and the position when the shear dilatation occurs are related to normal stress. In addition, shear dilatation occurs before the shear stress reaches peak value. In shear failure state, with the same height, the shear displacement increases as the normal stress increases. While with the same normal stress and at the same height, the shear displacement increases as the concrete content increases. A particle flow model of simple shear test between interface between coarse-grained soil and concrete is constructed by PFC (particle flow code). The disturbed height of the sample and the main influence factors are determined by analyzing the laws of particle motion at different heights inside the sample. The PFC results show disturbed height of the sample is related to maximum particle diameter of the soil, normal stress and roughness of the interface (with or without slurry) etc. In terms of the coarse-grained soil, the shear displacement is significant in the area which is close to the interface and about 3-4 times of the maximum particle diameter, and informed the obvious shear band. Further, the thickness of the interface can be regarded as the value.     

薄麻壳泡核桃芽接处理方式对成活率和生长的影响

为扩充薄麻壳泡核桃优株无形性繁殖材料,采用其优株穗条进行芽接,设置不同部位芽、不同嫁接高度和不同嫁接时间处理对其萌动、生长和嫁接成活率的影响,筛选出最佳芽接处理方式,提高芽接成活率.结果表明,优株对新梢长度的主效应影响显著,对芽萌动平均天数、新梢粗度和嫁接成活率的主效应影响不显著.嫁接时间对芽萌动天数、新梢长度、新梢粗...     

41个肉用老南瓜品种主要植物学性状分析

为科学评价国内肉用老南瓜品种,对参展的41个肉用老南瓜品种的始花期、第一坐瓜节位、果长、把长、茎粗、节间长、最大叶纵横径、单果重、果肉厚、可溶性固形物含量等主要植物学性状进行了多样性、相关性和聚类分析。结果表明:41个肉用老南瓜品种在把长、单果重、果长、肉厚等性状上变异幅度较大,在始花期性状上变异幅度较小;各性状之间均存在显著或者极显著的相关性。聚类分析表明41个老南瓜品种可以分为3组,其中第1组在多个性状上优于第2、3组群,但各组间及组内品种间的相似性较高。研究结果为老南瓜育种的优良性状选择和亲本选用提供了依据。     

等离子体对干旱胁迫下小麦种子萌发的生物学效应

用80~240 W射频等离子体处理小麦种子,在聚乙二醇（PEG-6000）模拟干旱胁迫条件下,研究了不同功率等离子体对小麦幼苗生长及抗旱性的影响。试验结果表明：不同功率的等离子体处理对干旱胁迫条件下小麦幼苗生长的影响效果不同,80~200 W处理对幼苗生长有不同程度的促进作用,根数、根长、株高、幼苗干重和根冠比各项指标均比对照有不同程度的提高,而240 W处理对小麦幼苗生长产生了抑制效应。其中160 W处理小麦种子在干旱胁迫下小麦幼苗根数、根长及干重分别比对照增加14.29%、16.94%和9.76%;丙二醛（MOD）含量及质膜透性比对照明显降低,防止或降低了膜质过氧化作用对膜的伤害;SOD、POD活性及脯氨酸含量均比对照高,表明保护性酶系统增强,一定程度上缓减了干旱胁迫对小麦幼苗的伤害,提高了其抗旱性。     

生态气候因子对黄土高原中部冬小麦粒重的影响规律分析

为了掌握黄土高原中部地区旱作冬小麦粒重受生态气候因素的影响规律,科学开发利用气候资源,提高冬小麦生产效益,使用1995—2009年位于黄土高原中部旱作农业区的甘肃西峰试验田资料和当地平行气象观测资料,应用统计学原理和分析方法,较系统地分析了冬小麦千粒重与灌浆速率及灌浆时间之间的增长规律,探讨了生态气候综合因子对千粒重的影响特征。结果表明：灌浆速率对千粒重的贡献比率为69%,是灌浆时间贡献比率的2.23倍;千粒重和灌浆速率逐年变化为线性增加趋势,反映出生态气候因子对冬小麦生长表征为适宜有利限度内,单位面积产量仍有增加潜能;千粒重与生态气候因子的逐步回归分析表明,灌浆期降水量每增加10 mm千粒重增加2.15 g,≥20℃的活动积温每增加100℃千粒重减少2.7 g,空气相对湿度每增大1%千粒重减少1.0 g。     

不同栽培条件对中籼稻茎秆抗倒伏性状的影响

研究了6个抗倒性不同的中籼稻品种在3个施肥水平,3种栽插密度下的茎秆物理性状。分析了它们与植株抗倒性能的关系。结果表明,栽培条件不同,植株株高不同,株高与抗倒性的关系亦不同。茎秆第一伸长节间长度与植株抗倒性能呈负相关,第二伸长节间长度与植株抗倒性能多呈负相关,第三伸长节间长度与抗倒性能呈正相关;基部茎秆粗度与植株抗倒性能多呈极显著正相关;基部茎秆厚度与植株抗倒性能呈极显著正相关。适宜的肥力水平和栽插密度可以使株高与茎秆物理性状优化组合。品种不同,植株茎秆物理性状不同,植株抗倒性能也不同。     

毕节高支苎麻主要农艺性状的遗传分析

对４份毕节高支苎麻的主要农艺性状进行遗传分析的结果表明：鲜皮出麻率和单纤维支数等农艺性状具有较大的遗传力,可在早代单蔸（株）选择或直接选择,产量、鲜皮厚、茎粗等性状的遗传力较低,应根据各性状同相关关系进行间接选择或推迟到晚期世代选择。遗传变幅较大的性状有鲜皮出麻率、株高、单蔸产量等,由于性状的改良效果主要由性状的遗传力和变异幅度及选择强度所决定,因此,在５％的选择强度下,遗传改良效果好的性状为株高     

Analysis on dynamic performance of hydrostaticoil film bearing throttled by capillary

With the linearization of the flow in oil chambers, the continuity equation of flow and the dynamic equation of the shaft are built for the hydrostatic journal bearing and thrust bearing respectively. Next, the transfer functions of the two bearings with capillary throttle are deduced. Then, the performance of the two bearings is simulated in Matlab. In general, the simulation results are well matched to the experimental data provided by Guangzhou Machine Tool Research Institute. It indicates that both of the models can predict the dynamic characteristic of the two bearings. Finally, the dynamics response of the hydrostatic thrust bearing is studied in various rotational speed of the shaft. Also, the dynamic performances of journal bearing are simulated in changing of inlet pressure and thickness of oil film.     

The Technology of Grouting into Separated Strata in Overburden and Computational Model

After coal mined, the balance of original stress state is to be broken. In the course of retribution, displacement and deformation in the overburden takes place with the working face advancing. The article points out that overburden can be divided into, in ascending, caving zone, fractured zone, bending zone and loose alluvium zone. The extracting space can be prevented from transferring to ground with injection material into bed-separation gap. Applying both mining subsidence theory and elastic thin plate theory, the computational model of subsidence control technology of grouting is worked out. The model can get rid of blindness of determining the position of separated strata, forecast the surface subsidence and provide the basis of theory for forecasting surface subsidence control technology of grouting.     

灌溉处理对苜蓿木质素单体分布影响的研究

为给苜蓿品质改良提供科学依据,选用‘新牧1 号’杂花苜蓿为试验材料,采用组织化学染色方法研究灌溉量对苜蓿茎木质素单体分布的影响。结果表明随灌溉量增加,株高和节数呈递增趋势;灌溉量对苜蓿茎木质素单体厚度和比例具有显著影响,750 m3/hm2灌溉量较其他灌溉处理有较多的木质素单体分布;2种木质素单体分布范围存在显著差异,S木质素单体厚度和比例均高于G木质素单体。     

高山杜鹃成都平原越夏生长研究

为加强对高山杜鹃的引种栽培,筛选出适合成都平原栽植的高山杜鹃品种,对引进的11个品种高山杜鹃的整株生长指标（冠幅、株高、地径、分蘖能力）、枝条生长指标（分枝数、最长分枝长度、单枝粗度、最长枝叶片数）、叶片生长指标（叶长、叶宽、叶片厚度）、夏稍长度以及热害指数进行评估。结果表明,引进的11个品种高山杜鹃均能在一定程度上适应成都平原越夏生长,其中‘王妃’的综合表现最好,尤其是其冠幅、株高、地径、最长分枝长度、单枝粗度、叶长、叶宽,在引种2个月后的增幅分别达到了131.43%、155.07%、53.79%、103.65%、26.66%、21.51%、27.34%;‘喜悦’的热害指数最低,几乎不受害。此外,‘粉蜜’、‘红溢’也表现不俗。因此,引进高山杜鹃品种‘王妃’、‘粉蜜’、‘红溢’、‘喜悦’适应成都平原的越夏生长,可进一步推广栽植。