谈森林抚育修枝方法及前景

树木修枝是森林抚育管理措施之一。是在自然整枝能力不良、通风不畅的林分中通过修枝人为的"助、减、缓"等技术措施,除去林冠下部已枯死或濒临枯死枝条及部分活枝的过程,从而调节、控制通风与透光,给树木生长发育创造适宜条件,造就通直干形、冠形优美的优质材质。分析修枝好处和坏处,然后进一步结合林区林分特点,确定修枝能否提升以防护性能为主的森林的防护能力提升、改善林木干形、增强天然更新能力等,得出了林区森林抚育是否需要修枝。     

小汽油机在园林修枝机上的应用研究

目前,国内有不少电动工具企业正在积极开发汽油机式园林工具,而此类工具的主要问题是振动及污染排放问题。文章分析了以小汽油机为动力的手持式修枝机的振动及污染排放,提出在汽油机与修枝机手柄之间改用弹簧联接、改进二冲程汽油机换气结构和选用合适的机油等改进措施。     

基于ADAMS的修枝机变速箱机械传动机构仿真分析研究

使用参数化建模软件Pro-E构建修枝机变速箱内的电机齿轮、双联齿轮、大齿轮及刀条、凸轮等部件,将构建的模型导入虚拟样机分析软件ADAMS中。通过添加约束和施加载荷。根据修枝机的实际工况,进行机械动力学仿真。分析研究两级机械传动齿轮啮合力、刀条往复运动速度、加速度及刀条冲击力时域和频域图,与理论值进行比较,验证仿真分析的准确性。     

杉木无节材人工修枝技术初探

杉木的节子严重地影响杉木的木材质量和利用,对杉木进行人工修枝处理是一项培育杉木无节材的有力措施。本文主要介绍了人工修枝的生物学原理及其对培育杉木无节材的影响,总结出杉木无节材人工修枝的关键技术。     

中华人民共和国机械行业标准电池式修枝剪

1范围本标准规定了单人操作的电池式修枝剪的基本参数和型式、技术要求、试验方法、检验规则、标志和包装等要求。     

人工林杉木胶合工艺优化研究

采用SAS全因子试验设计,研究了胶粘剂类型、涂胶量、单位压力、加压时间和胶合面纹理五个因子对人工林杉木木材胶合性能的影响,并对其胶合工艺进行了优化。研究结果表明:胶粘剂类型对杉木木材常态胶合剪切强度和木破率的影响不显著,但是老化处理后API和PF的胶合剪切强度和木破率比PVAc和UF的要高;在以API为胶粘剂时,涂胶量、单位压力、加压时间和胶合面纹理对杉木胶合剪切强度和木破率的影响显著,优化的胶合工艺为涂胶量250g/cm2,单位压力1.5 MPa,加压时间50 min和胶合面纹理为弦切面-弦切面。     

六种人工林木材胶合性能初步研究

初步研究了杉木、杨树、巨桉、尾巨桉、柠檬桉和窿缘桉等六种人工林木材的胶合性能,结果表明:胶合剪切强度沿杉木、杨树、巨桉、尾巨桉、柠檬桉和窿缘桉顺序增大;六种木材胶合性能差异显著,其中杉木、杨树、巨桉和尾巨桉胶合性能较好,表现为胶合剪切强度能达到标准要求、且木破率高;柠檬桉和窿缘桉木破率低,难于胶合,胶合性能有待改进;胶粘剂类型影响木材胶合性能,其中API和PF剪切强度和木破率平均值高于PVAc和UF;热压胶合的PF和UF的离散性比冷压胶合的API和PVAc要差。     

低质人工林木材家具关键连接部位接合方式研究

为了提高低质人工林木材家具关键连接部位接合强度,改善家具关键部位易松动、变形等质量缺陷。本文基于低质人工林木材材性,通过实验研究与实践经验相结合,对"T"型和"L"型部位的各种榫接合方式进行了研究分析。提出采用张紧木楔、多榫接合、胶黏剂强化以及局部补强等措施,优化现有接合方式,增强低质人工林木材家具关键连接部位的力学性能。     

人工林林地黑木耳(营养袋)栽培技术的研究

人工林林地食用菌栽培是林区非木材林产资源开发利用的主要内容之一。在管护经营好现有人工林资源条件下,在林地上栽培食用菌,获取一定经济效益,是管护经营的主要手段之一。为此,我们在哈尔滨市阿城区坪山镇附近周围落叶松人工林、樟子松人工林中进行了林地黑木耳栽培试验,取得了良好的经济效益。     

先进的林业技术装备是现代林业建设的支撑和保证

论述了先进林业技术装备在我国现代林业建设中的重要作用,分析了我国林业技术装备的发展现状和当前提升林业技术装备建设的有利条件,提出了林业技术装备建设发展的基本思路和措施。     

广东省林业技术装备提升规划综述

从建设广东现代林业出发,论述了广东省林业技术装备提升规划的重要性,提出了林业技术装备提升发展的规划原则、规划重点、总体目标和规划实施的政策保障措施。     

我国林业技术装备现状与发展趋势

论述了我国林业技术装备的发展现状,提出了林业技术装备发展中存在的主要问题,预测了林业技术装备未来的发展趋势。     

传统荷包边饰艺术分析

为了复原传统荷包工艺艺术的边饰工艺,对江南大学民间服饰传习馆、台州刺绣博物馆300余件荷包传世藏品的边饰进行分类研究,发现荷包边饰主要有编织带镶边、布条滚边和股线绣边3种基本形式。其中,织带镶边在葫芦荷包、扇套、眼镜袋等荷包中常见;布条滚边在江南腰包中最为普遍;股线绣边工艺最复杂,在装饰性强的方荷包、圆荷包中应用最多。可见,风格粗犷的大型荷包以布条滚边为主,精细绣花的小型荷包多以绣边装饰,织带镶边则具有一定的装裱作用。荷包边饰艺术融合了传统纹饰设计、配色、编织与刺绣等工艺。边饰选择遵循衬托点缀和功能适宜原则,荷包的造型类别、装饰风格以及制作材料共同决定了荷包边饰类型。     

桑枝削片粉碎机防缠绕装置研究

通过在QS-4型枝桠粉碎机上进行桑枝条粉碎试验得知,由于桑枝皮韧性强,削片粉碎时靠近底刀处的桑枝皮不易被切断,桑枝条皮在粉碎时不可避免地会缠绕在主轴上。本文分析了粉碎桑枝条时桑枝皮缠绕主轴的原因及危害,通过比较几种方案,设计了一个变直径离心盘,将其安装在刀盘一侧的主轴轴颈上,彻底解决了削片粉碎机粉碎桑枝条时桑枝皮缠绕主轴的问题。     

The effect of preventive trimming on weight bearing and force balance on the claws of dairy cattle

Claw disorders and lameness in dairy cattle are an increasing problem of the modern dairy industry. To prevent claw disorders from evolving from the subclinical to the clinical stage, trimming is the management practice most routinely applied. The goal of preventive trimming (Toussaint-Raven method) is to promote natural loading by increasing the weight-bearing contact area of the claws and improving the balance between the medial and lateral claw. The biomechanical effect of preventive claw trimming was investigated with the aid of pressure distribution and ground reaction force recordings of the standing cow sampled simultaneously at 250 Hz. It appeared that preventive trimming of the hind limbs (n = 10) brought the claws slightly more in balance. Before trimming, 80% of the total force is taken up by the lateral claw and 20% by the medial claw. After trimming, this becomes 70 to 30%, respectively. Thereby, a significant increase in the weight-bearing contact area from 27.5 to 40.0 cm2 was achieved, resulting in a significant decrease in average pressure. However, the claws remained subjected to unaltered, high maximum pressures after trimming. The suggestion was made that the main focus of claw trimming should not be force balance; instead, a reduction of local maximum pressures at the contact area should be targeted in such a way that the strongest parts of the claw capsule (i.e., the wall) will be subjected to the highest pressures.     

Genetic parameters for claw disorders and the effect of preselecting cows for trimming

Claw disorders are important traits relevant to dairy cattle breeding from an economical and welfare point of view. Selection for reduced claw disorders can be based on hoof trimmer records. Typically, not all cows in a herd are trimmed. Our objectives were to estimate heritabilities and genetic correlations for claw disorders and investigate the effect of selecting cows for trimming. The data set contained 50,238 cows, of which 20,474 cows had at least one claw trimming record, with a total of 29,994 records. Six claw trimmers scored 14 different claw disorders: abscess (AB), corkscrew claw (CC), (inter-)digital dermatitis or heel erosion (DER), double sole (DS), hardship groove (HG), interdigital hyperplasia (IH), interdigital phlegmon (IP), sand crack (SC), super-foul (SF), sole hemorrhage (SH), sole injury (SI), sole ulcer (SU), white line separation (WLS), yellow discoloration of the sole (YD), and a combined claw disorder trait. Frequencies of the claw disorders for trimmed cows ranged from 0.1% (CC, YD, HG) to 23.8% (DER). More than half of the cows scored had at least one claw disorder. Heritability on the observed scale ranged from 0.02 (DS, SH) to 0.14 (IH) and on the underlying scale from 0.05 to 0.43 in trimmed cows. Genetic correlations between laminitis-related claw disorders were moderate to high, and the same was found for hygiene-related claw disorders. The effect of selecting cows for trimming was first investigated by including untrimmed cows in the analyses and assuming they were not affected by claw disorders. Heritabilities on the underlying scale showed only minor changes. Second, different subsets of the data were created based on the percentage of trimmed cows in the herd. Heritabilities for IH, DER, and SU tended to decrease when a higher percentage of cows in the herd were trimmed. Finally, a bivariate model with a claw disorder and the trait “trimming status” was used, but heritabilities were similar. Heritability for trimming status was relatively high (0.09). Genetic correlations of trimming status with claw disorders were generally moderate to high. To conclude, the effect of selecting cows for trimming on the heritability for claw disorders is negligible. Selecting herds with a high fraction of cows being trimmed tended to decrease heritability. Trimming status, as such, is a heritable trait and correlated with claw disorders and is therefore an interesting trait to include in the genetic evaluation.     

Effects of two trimming methods of dairy cattle on concrete or rubber-covered slatted floors

This study monitored claw health, claw conformation, locomotion, activity, and step traits of cows from a single dairy herd that were trimmed according to the standard Dutch method or with an alternative “concave” trimming method. Half of the cows were kept in a stall section with concrete slatted floors in the alleys. The other cows were kept in a pen within the same housing with an identical concrete slatted floor in the alleys, but with a rubber top layer. All experimental cows were kept in the same environment for at least 3 mo before and after trimming. It was hypothesized that trimming for more-concave soles (i.e., with 3 to 5 mm of sole dug out under the claw bone) was preferred to the standard Dutch trimming with flat sole surfaces for cows kept in stalls with soft alley floors. None of the claw health or locomotion traits differed for the trimming methods. No interactions were found between flooring and trimming method. Floor effects were significant for several traits. Cows on the rubber-topped floors had significantly fewer sole hemorrhages (prevalence of 22 vs. 48% in mo 3) and larger claws (claw length 76.1 ± 5.0 vs. 72.5 ± 4.9 mm; heel height 49.3 ± 6.3 vs. 46.0 ± 6.4 mm; claw diagonal 129 ± 6.4 vs. 125 ± 6.9 mm), spent more time standing in the alleys (55.4 ± 2.8 vs. 49.6 ± 2.8%), and had higher activity (61.0 ± 3.7 vs. 53.0 ± 3.7 steps/h). This suggests greater claw comfort on rubber flooring compared with concrete flooring. Kinetic patterns during claw-floor contact while walking were similar for all treatments. During the double-support (stance) phase, claw-floor contact area increased to a maximum in the first 30% of double-support phase time, remained more or less stable until 80% of double-support phase time, and sharply decreased as the animal pushed off as shown by the change in center of pressure. A gradual change of center of pressure in the medial direction during double-support phase time was shown. The research hypothesis was rejected, but soft alley floors had subtle beneficial effects.     

使软压光机切纸边圆刀脱离DCS控制

K ü sters软压光机原配的切纸边圆刀设备操作是在DCS系统圆刀页面用键盘输入,原设计者只考虑了集中控制的优越性,但是忽略了切纸圆刀操作的安全实用性,易造成意外.通过更改软硬件,在圆刀机架旁操作,既安全又方便.本文详细介绍了纸边圆刀动作功能、DS/TS侧操作箱新增按钮、FB66相关步新改程序、FB10新增附加复位程序等改动的软硬件情况.     

苹果枝条多酚分离纯化及其抗氧化活性研究

研究了6种大孔树脂对苹果枝条多酚的吸附性能,筛选出分离苹果枝条多酚的最佳树脂为X-5,进一步研究X-5大孔树脂纯化多酚的工艺条件和技术参数。所得最佳纯化工艺为:上样浓度为1mg/m L,流速为1.0BV/h,pH5.0,以70%乙醇溶液为洗脱剂,洗脱流速为2.0BV/h。在此条件下,所得苹果枝条多酚的纯度为72.36%,提取率为0.82%。对纯化后的苹果枝条多酚抗氧化活性进行研究,结果表明:苹果枝条多酚具有较强的还原能力,对羟基自由基、DPPH自由基具有良好的清除能力。