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51.
基于EDA技术的自动立木整枝机无线遥控发射系统   总被引:4,自引:0,他引:4  
立木整枝是优质工业用材林定向抚育的重要环节,采用自动立木整枝机是实现高效、高质量和安全可靠整枝的有效途径。本文综合运用电子电路设计及优化技术、无线遥控及通信编解码技术,创造性地研制了基于CPLD的无线数字编码抗干扰自动立木整枝机无线遥控发射系统,通过优化CPLD内部逻辑电路有效消除了逻辑竞争冒险、降低了噪声干扰,确保了系统逻辑设计的正确性。该系统具有可靠、节能、抗干扰、工作效率高等优点。本研究成果及方法为推进其他林业机械的自动化与智能化进程提供了一种有效的新思路。  相似文献   
52.
Summary A system was developed for grouping tropical wood species for kiln drying based on similar estimated drying times. Six tropical species were subjected to drying and water soaking tests; variables were test temperature and specimen thickness. Soaking time, specimen thickness, and test temperature were used in an empirical model to predict drying times. The capability of the model to predict drying times was considered acceptable based on an adjusted coefficient of determination equal to 0.929 and an average error of 14 percent. The overall capability of the method proposed for grouping tropical hardwoods for drying is considered promising and worthy of further investigation.  相似文献   
53.
The aim of this study was to examine the effect of varying intracellular reactive oxygen species (ROS) levels during oocyte in vitro maturation with enzymatic ROS production systems (xanthine + xanthine oxidase or xanthine + xanthine oxidase + catalase), scavenger systems (catalase or superoxide dismutase + catalase) or cysteine on porcine oocyte maturation. Oocyte ROS levels showed an increase when H2O2 or O2? production systems were added to the culture medium (p < 0.05). On the other hand, the presence of ROS scavengers in the maturation medium did not modify oocyte ROS levels compared with the control after 48 h of maturation, but the addition of cysteine induced a decrease in oocyte ROS levels (p < 0.05). The ROS production systems used in this work did not modified the percentage of oocyte nuclear maturation, but increased the decondensation of sperm head (p < 0.05) and decreased the pronuclear formation (p < 0.05). In turn, the addition of O2? and H2O2 scavenging systems during in vitro maturation did not modify the percentage of oocytes reaching metaphase II nor the oocytes with decondensed sperm head or pronuclei after fertilization. However, both parameters increased in the presence of cysteine (p < 0.05). The exogenous generation of O2? and H2O2 during oocyte in vitro maturation would not affect nuclear maturation or later sperm penetration, but most of the spermatozoa cannot progress to form the pronuclei after fusion with the oocyte. The decrease in endogenous ROS levels by the addition of cysteine would improve pronuclear formation after sperm penetration.  相似文献   
54.

Background

Metabolic profile was initially designed as a presymptomatic diagnostic aid based on statistical analyses of blood metabolites to provide an early warning of certain types of metabolic disorder. However, there is little metabolic profile data available about Korean Hanwoo cows. Therefore, this study aimed to determine the reference intervals of metabolic profile for Korean Hanwoo cows.

Methods

Healthy animals (2,205) were selected and divided into early (day 1 to 95), middle (day 96 to 190) and late (day 191 to 285) period according to their gestating period. Metabolic profile including total protein (TP), albumin (Alb), urea (UREA), glucose (Glu), total cholesterol (T-Cho), long-chain fatty acid (LCFA), aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (GGT), creatinine (Crea), calcium (Ca), inorganic phosphorous (iP) and magnesium (Mg) were analyzed using a TBA-40FR automatic biochemical analyzer. The data of Korean Hanwoo cows were then compared to those of the Japanese Wagyu cows.

Results

Most of the data of the Korean Hanwoo cows were relatively higher than those of Japanese Wagyu cows, with the exception of Glu and GGT. This may indicate that the nutritional level of feed for the Korean Hanwoo cows was higher than that of the Japanese Wagyu cows because of the different feeding system. In particular, relatively higher levels of UREA and LCFA were observed in the Korean Hanwoo cows, and this may also contribute to the low reproduction efficiency.

Conclusions

These findings may provide some theoretical basis for understanding the reproductive and feeding situation of Korean Hanwoo cows.  相似文献   
55.
为评估白足蚜小蜂Aphelinus albipodus对桃蚜Myzus persicae的防控效果,在室内测定了白足蚜小蜂对不同发育阶段桃蚜的功能反应和搜寻效应,并对种内干扰和分摊竞争强度进行了比较.结果表明:白足蚜小蜂对不同发育阶段桃蚜的取食量和寄生量均随着蚜虫密度增加而增加,取食量和寄生功能反应均符合HollingⅡ模型.白足蚜小蜂对桃蚜的理论最大取食量2.809头,瞬时攻击率0.218,处理时间0.023 d;白足蚜小蜂对3~4日龄桃蚜寄生量最大,为47.62头,寄生瞬时攻击率0.723,处理时间0.021 d.搜寻效应均随蚜虫密度的增加而下降,且与蚜虫密度呈负相关.白足蚜小蜂个体之间存在种内干扰作用,随着自身密度增加,单头寄生率相对下降,分摊竞争强度增大,干扰效应符合Hassell-varley模型.由功能反应、种内干扰等指标可见白足蚜小蜂对桃蚜具有较好的防控作用.  相似文献   
56.
为深入了解油用亚麻主要品质和农艺性状的遗传变异,以253份油用亚麻种质为研究对象,在3个环境下(内蒙古呼和浩特市、集宁市和锡林郭勒盟太仆寺旗)对其全生育天数、株高、工艺长度、单株果数、每果粒数、单株粒重、千粒重和分枝数8个农艺性状及棕榈酸、硬脂酸、油酸、亚油酸、亚麻酸、粗脂肪含量6个品质性状进行鉴定。结果表明,8个农艺性状的变异系数为5.66%~42.65%;6个品质性状的变异系数为4.10%~30.14%。全生育天数在太仆寺旗表现最长,为112.51 d;千粒重和单株粒重在集宁地区表现最大,分别为5.94和0.55 g;果粒数和单株果数在呼和浩特地区表现最多,分别为5.65和16.90;粗脂肪和亚麻酸含量在太仆寺旗地区表现最大,分别为39.53%和53.45%;亚油酸和棕榈酸含量在集宁地区最大,分别为16.41%和5.09%;油酸和硬脂酸含量在呼和浩特地区表现最大,分别为24.03%和8.31%。聚类分析表明,253份油用亚麻种质被划分为4个类群,相同地理来源的油用亚麻种质被聚到1个类群,为油用亚麻种质资源的收集保存与繁殖提供了科学依据。  相似文献   
57.

Background

Detection of clinically relevant pain relief in cats with degenerative joint disease (DJD) is complicated by a lack of validated outcome measures and a placebo effect.

Hypothesis/Objectives

To evaluate a novel approach for detection of pain relief in cats with DJD.

Animals

Fifty‐eight client‐owned cats.

Methods

Prospective, double‐masked, placebo‐controlled, stratified, randomized, clinical study. Enrolled cats were 6–21 years of age, with owner‐observed mobility impairment, evidence of pain in at least 2 joints during orthopedic examination, and overlapping radiographic evidence of DJD, and underwent a 2‐week baseline period, 3‐week treatment period with placebo or meloxicam, and 3‐week masked washout period. Outcome measures were evaluated at days 0, 15, 36, and 57.

Results

Both groups significantly improved after the treatment period (day 36) on client‐specific outcome measures (CSOM) and feline musculoskeletal pain index (FMPI) (P < .0001 for both); there was no difference between the groups on CSOM or FMPI score improvement. After the masked washout period, more cats that received meloxicam during the treatment period had a clinically relevant decrease in CSOM score (P = .048) and FMPI score (P = .021) than cats that received placebo.

Conclusions and Clinical Importance

Using both a client‐specific and a general clinical metrology instrument, owners of cats with DJD were able to detect evident recurrence of clinical signs after withdrawal of active medication than after withdrawal of placebo, and that this study design might be a novel and useful way to circumvent the placebo effect and detect the efficacy of pain‐relieving medications.  相似文献   
58.
随着城市的发展,城市公共空间对城市生活的重要性不断凸显,城市微型公共空间作为其层次结构中不可或缺的一环,在世界范围内也得到了长足发展。但对于我国城市微型公共空间景观设计领域而言,却一直未能得到足够的重视。以深圳市罗湖区嘉宾公园为研究对象,阐述城市微型公共景观设计对于城市公共空间层次结构的重要意义,并展现其为城市所带来的独特魅力。深圳市罗胡区嘉实公园的建成为我国城市微型公共空间提供了一个极佳的参考样本。  相似文献   
59.
Optimal conditions of 6‐dimethylaminopurine (6‐DMAP) for triploidy induction in the blacklip abalone Haliotis rubra (Leach, 1814) were investigated, targeting inhibition of second polar body (PB2) formation. Two experiments were conducted at a water temperature of 17.5–18.5°C where factorial combination of (1) four dosages (DSs) of 100, 150, 200 and 250 μM 6‐DMAP, four starting times (STs) of 15, 20, 25 and 30 min post fertilization, and two treatment durations (TDs) of 20 and 30 min and (2) three DSs of 50, 100 and 150 μM 6‐DMAP, three STs of 15, 20 and 25 min post fertilization, and three TDs of 10, 20 and 30 min, were applied respectively. Day 3 larvae were sampled for triploidy and survival. Percent triploidy was verified using flow cytometry (FCM). Results show that optimal inductions that combine both high rates of triploidy and reasonable survival were those treatments commenced 15 or 20 min post fertilization and continued for 20 or 30 min, using 100 μM 6‐DMAP. These conditions induced rates of triploidy and relative survival of 80.5–93.3% and 36.5–40.2%, respectively, in the first experiment, and corresponding rates were 79.1–93.6% and 20.7–43.0% in the second experiment. High percent triploidy were also obtained in a number of treatments using 150 μM 6‐DMAP, but with overall survival rates generally lower than those using 100 μM 6‐DMAP.  相似文献   
60.
Growth and mortality of sibling triploid and diploid Sydney rock oysters, grown at two tidal heights, three stocking densities and three different sites on the Camden Haven River estuary, were compared. Triploids grew faster than diploids. The majority of the growth rate difference occurred after the oysters reached 2 years of age. By 3.2 years, triploids were 49% heavier than diploids. Oysters grown intertidally were larger than those grown subtidally. Oysters stocked at the lightest density of 2 L per basket grew to a significantly larger size than baskets stocked at 3 or 4 L. Growth rates were significantly different at the three sites. Growth was reduced the further the oysters were from the mouth of the estuary. There was no significant difference in mortality between ploidy level, but there were differences between tidal heights, stocking densities and sites. Intertidal oysters suffered higher mortality than subtidal. Oysters stocked at the highest density had a significantly higher mortality than the lowest density; neither of these was significantly different from the medium density. The site closest to the mouth of the estuary had significantly lower mortality than the middle and upper estuary sites.  相似文献   
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