Light Simplified Foxtail Millet Cultivation Technique Adopting Furrow Sowing beside Plastic Film Covering Micro-ridges

In order to solve the problem that dry-land foxtail millet production completely relies on rainwater with the characteristics of low instable yield, manual thinning and weeding, high labor intensity, and labor and time saving, Millet Research Institute of Hebei Academy of Agriculture and Forestry Sciences integrated furrow sowing beside plastic film covering micro-ridges, simplified cultivation and mechanized production, forming the simplified foxtail millet cultivation technique adopting furrow sowing beside plastic film covering micro-ridges. This study introduced the technique points of the simplified foxtail millet cultivation technique adopting furrow sowing beside plastic film covering micro-ridges, including preparation before sowing,sowing, attached agricultural machines, field management, harvest and residual film recovery.

Land use and cover change and influencing factor analysis in the Shiyang River Basin,China

Land use and cover change(LUCC)is the most direct manifestation of the interaction between anthropological activities and the natural environment on Earth's surface,with significant impacts on the environment and social economy.Rapid economic development and climate change have resulted in significant changes in land use and cover.The Shiyang River Basin,located in the eastern part of the Hexi Corridor in China,has undergone significant climate change and LUCC over the past few decades.In this study,we used the random forest classification to obtain the land use and cover datasets of the Shiyang River Basin in 1991,1995,2000,2005,2010,2015,and 2020 based on Landsat images.We validated the land use and cover data in 2015 from the random forest classification results(this study),the high-resolution dataset of annual global land cover from 2000 to 2015(AGLC-2000-2015),the global 30 m land cover classification with a fine classification system(GLC_FCS30),and the first Landsat-derived annual China Land Cover Dataset(CLCD)against ground-truth classification results to evaluate the accuracy of the classification results in this study.Furthermore,we explored and compared the spatiotemporal patterns of LUCC in the upper,middle,and lower reaches of the Shiyang River Basin over the past 30 years,and employed the random forest importance ranking method to analyze the influencing factors of LUCC based on natural(evapotranspiration,precipitation,temperature,and surface soil moisture)and anthropogenic(nighttime light,gross domestic product(GDP),and population)factors.The results indicated that the random forest classification results for land use and cover in the Shiyang River Basin in 2015 outperformed the AGLC-2000-2015,GLC_FCS30,and CLCD datasets in both overall and partial validations.Moreover,the classification results in this study exhibited a high level of agreement with the ground truth features.From 1991 to 2020,the area of bare land exhibited a decreasing trend,with changes primarily occurring in the middle and lower reaches of the basin.The area of grassland initially decreased and then increased,with changes occurring mainly in the upper and middle reaches of the basin.In contrast,the area of cropland initially increased and then decreased,with changes occurring in the middle and lower reaches.The LUCC was influenced by both natural and anthropogenic factors.Climatic factors and population contributed significantly to LUCC,and the importance values of evapotranspiration,precipitation,temperature,and population were 22.12%,32.41%,21.89%,and 19.65%,respectively.Moreover,policy interventions also played an important role.Land use and cover in the Shiyang River Basin exhibited fluctuating changes over the past 30 years,with the ecological environment improving in the last 10 years.This suggests that governance efforts in the study area have had some effects,and the government can continue to move in this direction in the future.The findings can provide crucial insights for related research and regional sustainable development in the Shiyang River Basin and other similar arid and semi-arid areas.

Modification of the Hybridization Gap by Twisted Stacking of Quintuple Layers in a Three-Dimensional Topological Insulator Thin Film

Twisting the stacking of layered materials leads to rich new physics. A three-dimensional topological insulator film hosts two-dimensional gapless Dirac electrons on top and bottom surfaces, which, when the film is below some critical thickness, will hybridize and open a gap in the surface state structure. The hybridization gap can be tuned by various parameters such as film thickness and inversion symmetry, according to the literature. The three-dimensional strong topological insulator Bi(Sb)Se(Te) family has layered structures composed of quintuple layers(QLs) stacked together by van der Waals interaction. Here we successfully grow twistedly stacked Sb_2Te_3 QLs and investigate the effect of twist angels on the hybridization gaps below the thickness limit. It is found that the hybridization gap can be tuned for films of three QLs, which may lead to quantum spin Hall states.Signatures of gap-closing are found in 3-QL films. The successful in situ application of this approach opens a new route to search for exotic physics in topological insulators.

Simulation Experiment of Air Temperature Variation in Multi-film Covering at Night

In order to provide theoretical basis and data support for improving the production mode of covering,this study investigated the nighttime air temperature formed by multiple layers of films with tunnel sheds and small tunnel sheds as trial subjects.The experiment was carried out in four tunnel sheds with 0 or 2 small tunnel sheds covered by 0,1,2 and 3 layers of films,respectively in Jinan,Shandong Province in winter of 2018.The nighttime air temperatures of tunnel sheds and small tunnel sheds formed by 1,2,3 and 4 layers of plastic film were measured and analyzed to simulate the temperature environment of early-spring season.The results showed that there were little differences between the nighttime air temperatures inside the tunnel sheds which was installed 0-3-layer small tunnel sheds inside,and there were uncertainty in the values of the air temperatures inside and outside the tunnel sheds;and the nighttime temperature conditions were constantly improved with the number of plastic film layers increasing under the conditions of this study.The analysis indicated that the mechanism of raising the temperature surrounded by plastic film was not only due to its own thermal parameter (thermal conductivity).MATLAB fitting analysis results showed that the increment of nighttime temperature in multi-film coverings became smaller with the number of film layers increasing.In this study,the number of layers in multi-film covering should not exceed 5 layers.

THEORETICAL STUDY OF THREE-DIMENSIONAL NUMERICAL MANIFOLD METHOD

The three-dimensional numerical manifold method（NMM） is studied on the basis of two-dimensional numerical manifold method. The three-dimensional cover displacement function is studied. The mechanical analysis and Hammer integral method of three-dimensional numerical manifold method are put forward. The stiffness matrix of three-dimensional manifold element is derived and the dissection rules are given. The theoretical system and the numerical realizing method of three-dimensional numerical manifold method are systematically studied. As an example, the cantilever with load on the end is calculated, and the results show that the precision and efficiency are agreeable.

复合材料薄膜盖结构与功能一体化设计

目的解决传统硬质泡沫塑料易碎盖存在的承压能力不足、冲破性能不稳定、不能有效防潮控湿、电磁兼容性差等缺陷。方法以某型导弹武器系统发射筒密封盖为主要应用对象开展薄膜盖设计,主要包括总体结构设计、零部件设计、功能设计及仿真验证。结果薄膜盖经密封、承压、冲破、电磁兼容等性能考核,均满足装备贮存使用要求,冲破盖体所受的最大峰值冲击力可稳定保持在1200~1600 N。结论建立了薄膜盖结构与功能一体化设计方法,可满足在研型号对新型密封盖的设计需求,并为新型号弹箭发射筒大尺寸密封盖的顺利研制提供技术储备。

干旱地区不同颜色覆膜对土壤水热及茴香产量的影响

以“民勤2号”茴香为试材,采用大田随机区组设计方法,设置无覆盖(NM)、黑色地膜覆盖(BM)、透明地膜覆盖(TM)3个试验处理,测定了干旱区不同颜色覆膜下茴香农田土壤的含水量、温度、株高及产量,通过比较测定数据探究不同颜色覆膜对土壤水热及茴香产量的影响,以期为该地区茴香覆膜栽培技术应用提供参考依据。结果表明:覆膜可以提高茴香全生育期及不同土层土壤含水量,BM显著高于其他处理;不同生育期茴香农田土壤温度及不同生育期0~100 cm土层的土壤温度均表现为覆膜处理高于无覆膜处理,且BM>TM>NM;茴香株高、产量试验均表现为覆膜处理高于无覆膜处理,且BM增加效果最为显著。综上,覆黑色地膜在提高土壤含水量和土壤温度、增加茴香产量方面具有重要作用。

Discontinuity development patterns and the challenges for 3D discrete fracture network modeling on complicated exposed rock surfaces

Natural slopes usually display complicated exposed rock surfaces that are characterized by complex and substantial terrain undulation and ubiquitous undesirable phenomena such as vegetation cover and rockfalls.This study presents a systematic outcrop research of fracture pattern variations in a complicated rock slope,and the qualitative and quantitative study of the complex phenomena impact on threedimensional(3D)discrete fracture network(DFN)modeling.As the studies of the outcrop fracture pattern have been so far focused on local variations,thus,we put forward a statistical analysis of global variations.The entire outcrop is partitioned into several subzones,and the subzone-scale variability of fracture geometric properties is analyzed(including the orientation,the density,and the trace length).The results reveal significant variations in fracture characteristics(such as the concentrative degree,the average orientation,the density,and the trace length)among different subzones.Moreover,the density of fracture sets,which is approximately parallel to the slope surface,exhibits a notably higher value compared to other fracture sets across all subzones.To improve the accuracy of the DFN modeling,the effects of three common phenomena resulting from vegetation and rockfalls are qualitatively analyzed and the corresponding quantitative data processing solutions are proposed.Subsequently,the 3D fracture geometric parameters are determined for different areas of the high-steep rock slope in terms of the subzone dimensions.The results show significant variations in the same set of 3D fracture parameters across different regions with density differing by up to tenfold and mean trace length exhibiting differences of 3e4 times.The study results present precise geological structural information,improve modeling accuracy,and provide practical solutions for addressing complex outcrop issues.

生物降解地膜水蒸气透过量试验中不同条件对结果的影响

生物降解地膜相比传统聚乙烯地膜,水蒸气透过量要大。因此,研究影响生物降解地膜水蒸气透过量因素就很重要。本文通过对2种不同厚度的样品分别进行不同称量时间间隔的水蒸气透过量测定,并利用GB/T 35795—2017《全生物降解农用地面覆盖薄膜》水蒸气透过量检验指标和GB/T 1037—2021《塑料薄膜与薄片透水蒸汽性能测定杯式增重与减重法》规定的测试方法,以恒温恒湿箱增重法为试验方法研究了称量时间间隔对水蒸气透过量的影响关系。结果表明:1)厚度对地膜的水蒸气透过量有影响,随着厚度的增加,水蒸气透过率会减少;2)水蒸气透过量测试过程中,称量时间间隔会影响结果准确性,在满足GB/T 1037—2021中要求的干燥剂吸湿总量不超过10%的前提下,称量时间间隔与结果呈负相关性。

秸秆深埋配施硫酸铝对西辽河平原地区苏打盐碱土水盐运移的影响

为探索秸秆深埋和硫酸铝改良剂配施交互作用对苏打盐碱地水盐运移的影响,在通辽市科尔沁左翼中旗开展覆膜滴灌下不同硫酸铝用量与秸秆深埋的田间试验,以甜菜为指示作物,常规处理为对照(CK),在有无秸秆深埋(A、B)的条件下分别设置4水平硫酸铝添加量(30、60、90、120 g/m^(2)),揭示硫酸铝用量、秸秆深埋与土壤含水率、盐分的相关关系,提出覆膜滴灌及秸秆深埋下适宜的硫酸铝用量。结果显示,未添加秸秆处理中B3处理0~50 cm土体平均含水率最高(23.8%),比CK高8.2%,且平均含盐量最低(1.69 g/kg),比CK低12.6%;添加秸秆处理中A3处理0~50 cm土体平均含水率最高(26.6%),比B3处理高2.8%,平均含盐量也最低(1.57 g/kg),比B3处理低19%,且平均积盐率最低,比B3处理降低7.6%;A3处理在10~20和20~30 cm处土壤含水率均显著高于B3处理(P<0.05),在0~10和20~30 cm处土壤含盐量较B3处理显著降低(P<0.05);A3处理0~30 cm各土层均有脱盐趋势,达到显著水平(P<0.05),平均脱盐率11.5%;硫酸铝和秸秆深埋交互作用与土壤含水率呈极显著正相关(0.808),与土壤含盐量呈显著负相关(-0.564)。秸秆深埋和硫酸铝改良剂综合作用可有效降低土壤pH值0.53~0.94,缓解土壤碱化度20.5%~21.9%。覆膜滴灌及秸秆深埋下硫酸铝用量在72~104 g/m^(2)为适宜当地的推荐用量。研究结果可为西辽河平原地区盐碱土壤改良提供理论依据。

覆膜种植措施对垄作农地土壤优先流空间异质性的影响

为进一步针对垄作田间农业生产制定高效的需水用肥策略提供科学支撑,将野外染色示踪试验和室内土柱水分入渗实验相结合,利用图像形态学解析、模拟入渗分析、熵权分析和灰色系统理论分析等方法,对垄作覆膜和垄作(对照)种植措施下的农地土壤优先流空间异质性特征进行分析,阐明覆膜种植措施下的垄作农地土壤优先流空间分布及其运动变化规律,揭示覆膜种植措施影响下的优先流与垄作田间土壤水分运动过程的作用关系。结果表明:在相同外部供水条件下,垄作覆膜种植农地的水分集中分布在0~10 cm土壤表层,随着土壤深度的增加分布范围逐渐缩小,其土壤染色复杂程度随着土壤深度的增加先增大后减少。而垄作种植农地在10~30 cm土壤深度范围内的水分分布出现显著的指状优先流分化现象。同时,垄作覆膜农地土壤达到饱和状态的时间是垄作农地的1.36倍,其单位时间内的平均土柱水流出流量(质量流率为0.20 g/s)显著(P<0.05)小于垄作农地(质量流率为0.35 g/s),土壤优先流程度相较更高,土壤属性中饱和导水率对优先流程度影响最大。垄作覆膜种植措施相较垄作在一定程度上能够进一步降低农地土壤空间内优先流的发生及其分布,减少水分向土壤深层渗漏,起到一定程度的蓄水保墒作用。

青贮玉米光合特性及产量对全膜覆盖不同滴灌量的响应

为探讨全膜覆盖下滴灌量对河西灌区青贮玉米光合特性及产量的影响,以甘肃省河西灌区W_(1)(节水30%)、W_(2)(节水20%)、W_(3)(节水10%)、W_(4)(传统灌水)4种滴灌处理下青贮玉米为研究对象,分析不同滴灌处理下青贮玉米关键生育期光合生理特性、水分利用效率及产量的变化特征。结果表明:①除拔节期外,W_(3)、W_(4)处理下青贮玉米叶片净光合速率(P_(n))、蒸腾速率(T_(r))和气孔导度(G_(s))均显著高于W_(1)和W_(2)处理(P<0.05),而W_(3)和W_(4)处理间无显著差异。②抽雄期至成熟期,W_(1)、W_(2)处理下青贮玉米叶片光合水分利用效率(WUE)显著高于W_(3)和W_(4)处理(P<0.05),但拔节期内,W_(3)处理下青贮玉米WUE显著高于其他处理。③在不同生育期、不同滴灌处理下,青贮玉米叶片的P_(n)、T_(r)、G_(s)和胞间CO_(2)浓度(C_(i))都呈现明显的光合日变化特征;W_(3)、W_(4)处理下各光合特征的日变化幅度、峰高、峰值与W_(1)和W_(2)处理之间存在显著差异(P<0.05)。④与W_(1)和W_(2)处理相比,W_(3)和W_(4)处理显著增加青贮玉米茎重、穗重及生物产量(P<0.05),但相对于W_(3)处理而言,W_(4)处理对青贮玉米产量及其构成因素的影响并不显著。综合青贮玉米产量与光合特性、水分利用效率的表现,在全膜覆盖的传统施肥条件下,滴灌量在5535 m^(3)/hm^(2)时青贮玉米的产量最佳。

Simulation of temperature distribution in double-row potato ridges mulched with plastic film covered with soil

In Northwest China,potatoes are cultivated on double-rows of each ridge which is mulched with plastic film,and the film is covered with some of soil.While effective in retaining soil moisture,this technique can render the potato seedlings prone to be burned if they are not released from the plastic film in time.In this study,the model of convective heat transfer of potato ridge under solar radiation and atmospheric radiation is established by the Fluent software.The processes of the heat transfer of potato ridge was simulated for a certain day,and the temperature distribution in the potato ridge was monitored over time.The temperature distribution of soil in the growth layer of potato plants was analyzed under different thickness and widths of the covering soil on the film.The results showed that with the increase of covering soil thickness and width,the time for soil at different depth to reach the peak-temperature was delayed,and the daily temperature change of soil where the different depths layer of potato plants growth was reduced.At that time,a binary regression equation of offset temperature was constructed by using the Response Surface Method.The best parameter combination for covering soil on the plastic film is a thickness of 50 mm and a width of 280 mm in the cold and arid areas of Northwest China.However,the offset temperature(PT)first decreased and then almost remained unchanged with the increase of covering soil thickness.Considering the operational efficiency and power consumption of soil covering devices in the field,the unchanged width of the covering soil is 200 mm.The field experiments have shown that a 50 mm thick of soil covering is beneficial for the growth of potato plants and a 200 mm width of soil covering is beneficial for the growth of potato plants.The height of potato plants was 21 cm,and the natural emergence rate of potatoes was 95.8%on June 9,2024.The environment of soil covered could provide theoretical support for the mechanized planting of potatoes.

基于隶属函数法对不同材料膜覆盖花生影响评价

利用隶属函数法对不同材料膜覆盖下的花生生长影响进行了评价,结果表明,形态学方面,塑料地膜覆盖效果最优,纤维黑色纸膜次之,对照(无覆盖)最差;光合方面,液态生物降解膜覆盖效果最优,粉剂生物降解膜次之,对照最差;水分利用方面,粉剂生物降解膜覆盖效果最优,液态生物降解膜次之,对照最差;产量方面,粉剂生物降解膜效果最佳,塑料地膜和液态生物降解膜次之,对照亦最差。隶属函数法可以解决同类间不同指标所得的结论不一致的矛盾,可以准确反映出不同材料膜覆盖对花生生长的影响。

空调座盖塑件模内装饰成型工艺与模具设计

针对空调座盖采用塑件模内装饰(IMD)方式进行成型的要求,为其设计了一种基于高压成型3D膜片镶件的IMD成型工艺用于该塑件的成型。工艺中,IMD塑件的保护层3D膜片镶件使用0.25 mm聚甲基丙烯酸甲酯(PMMA)薄膜高压压制+真空吸附3D成型,内衬使用聚碳酸酯/丙烯腈-丁二烯-苯乙烯共聚物(PC/ABS)合金注塑成型。所设计的IMD工艺路径包括9道工序。其中3D膜片镶件高压成型模具为一种模具闭合后具备膜片上表面高压压制和下表面真空吸附能力的双作用成型凸模,对应的高压成型工艺参数为:成型压力(35±1)Kg/保压时间(7.0±1)s/模具温度183℃。内衬的注塑成型中,内衬注塑模具为一种两板式单浇口热流道倒装模具,3D膜片镶件在型腔镶件内的定位依靠2个定模限位滑块进行定位,塑件的脱模由倒装模具动模内设置的2个油缸驱动推板及其上的10个斜顶和14根顶针共同顶出来实现。运用CAE软件Moldflow中“重叠注塑”分析序列对内衬的注塑成型进行了内衬/3D膜片镶件之间的重叠注塑成型仿真优化分析,优化结果为:内衬模腔注塑时,热浇口直径取Ø4 mm,模温79℃,熔料温度260℃,注塑压力90 MPa,保压分4段保压,分别为40 MPa-2 s/30 MPa-2 s/15 MPa-2 s/10 MPa-1.5 s。

基于刚柔流耦合的水稻覆膜插秧机破膜装置设计

针对现有水稻覆膜插秧机无破膜装置或破膜装置结构不合理导致伤根率高等问题,设计了一种水稻覆膜插秧机破膜装置,以有限元方法建立了破膜插秧作业的刚柔流耦合模型。分析了各试验因素对评价指标的影响,并进行了多目标优化;获得了破膜装置最优结构和工作参数组合,并通过台架试验进行验证。研究可为水稻覆膜插秧机破膜装置结构优化和水田覆膜复杂作业环境下的可视化互作分析提供理论依据和技术支持。

跨越式膜上对行覆土装置设计与覆土性能研究

针对西北寒旱区马铃薯全膜覆盖种行覆土栽培农艺要求,研制一种跨越式膜上对行覆土装置。解析跨越式提土装置和侧向对行覆土装置作业机理,确定了各个部件的核心作业参数。运用离散单元法(DEM)进行了对行覆土仿真试验,结合Box-Behnken试验设计原理,采用三因素三水平响应曲面法,建立了覆土宽度和覆土厚度的回归模型,优化得到跨越式膜上对行覆土装置的最优作业参数组合为螺旋输土器转速135 r·min^(-1),覆土器开口长度100 mm,覆土器离地高度为233 mm。田间试验表明,设计的跨越式对行覆土装置满足马铃薯种植农艺要求,马铃薯幼苗自然出苗率达到92.5%,同时烧苗率为7%。

垄上破膜覆土一体机设计与仿真

针对贵州省铜仁市植烟区膜后打孔投苗移栽方式存在的烟苗根部覆土不足、苗株周围易长草问题,设计了一款适合于铜仁市植烟区烟叶生产的乘坐式垄上破膜覆土一体机。该机由增程式发电机、铅酸电池组、行走装置、取土运土装置、破膜覆土装置、控制面板、机架及驾驶位等组成。利用Solidworks软件建立了双曲柄多连杆鸭嘴破膜覆土机构虚拟样机模型,经模型简化导入ADAMS中进行仿真分析,得到其运动轨迹和X、Y方向位移与时间变化曲线。结果表明,设计的双曲柄多连杆鸭嘴破膜覆土机构满足55 cm定株距破膜和作业效率0.067 hm^(2)/h的要求,验证了其结构选择和参数设计的合理性。该机能够代替人工膜上覆土作业、降低作业成本、提高覆土效率,具有推广使用价值。

不同细度重质碳酸钙在PVC压延膜中的应用研究

分析了两种矿种制备出的不同细度重质碳酸钙(南召1号~8号和连州1号~5号)的性能指标,研究了这些不同细度重质碳酸钙粉体应用于PVC压延膜对其白度、拉伸强度、耐热性能与遮盖性能的影响。研究结果发现:从南召1号到8号,粉体的粒径在逐渐变小,粒径分布逐渐变窄,白度和吸油值均在逐渐增加;连州1号到5号粉体具有类似的变化规律。南召1号至8号粉体随着粉体白度和细度的提升,其应用于PVC压延膜的白度、拉伸强度、耐热性和遮盖力性能都在明显提升,其中,5号以上的产品填充PVC压延膜可以获得较好的综合性能,7号具有最佳的综合性能。连州1号至5号填充PVC压延膜,白度变化不大,拉伸强度增大,耐热性能和遮盖性能逐渐变好,其中,3号以上的产品均可获得较好的综合性能,5号具有最佳的综合性能。