单圆盘甘蔗切割器影响破头率的运动学仿真

利用有限元软件ANSYS对甘蔗切割进行有限元分析,制定了单圆盘甘蔗切割器切割甘蔗的坏切割状态判别标准,通过物理试验制定了刀盘压破蔗头的判别标准.利用动力学仿真分析软件ADAMS进行了切割器连续切割多根甘蔗的运动学仿真,定量研究了影响切割状态和压破蔗头的各因素及交互作用对破头率的影响机理.结果表明.小频率和小速比、小振幅和少刀片的组合有利于降低破头率,当频率、振幅为零,速比为24,倾角为15°,刀片数目为2片时破头率为6.7%.     

海南野生兰花观赏性状评价

为保护、开发利用海南野生兰科植物研究提供数据参考,该文对海南野生兰科植物的观赏性状进行了数据采集、描述,较为全面的观察和评价.按观赏特性可分为大花型(23种)、多花型(23种)、长花序型(15种)、特长花序型(8种)、圆锥花序型(12种)、具香气型(21种)6个类型.同时筛选了62种可直接开发利用的原生种,并从观赏角度将其划分为四类:观花类(15种)、观叶类(3种)、花叶兼具类(27种)、株型类(17种).     

Transthoracic echocardiographically-guided interventional cardiac procedures in the dog

ObjectivesInterventional cardiac procedures are traditionally performed using fluoroscopy, or, more recently, transesophageal echocardiography (TEE). Neither modality is widely available to practicing cardiologists worldwide. We examined whether balloon valvuloplasty of pulmonic stenosis (PS) and transarterial occlusion of patent ductus arteriosus (PDA) in dogs could be performed safely with transthoracic echocardiography (TTE).AnimalsA prospective consecutive case series of 26 client-owned dogs with PS (n = 10) and PDA (n = 16).MethodsThe cardiovascular procedures were performed using TTE. Each dog was positioned on a standard echocardiography table in right lateral recumbency (dogs with PS) or left lateral recumbency (dogs with PDA). Guide wires, balloon catheters, Amplatz^® Canine Ductal Occluder (ACDO) delivery sheaths, and ACDO were imaged by standard echocardiographic views optimized to allow visualization of the defects and devices.ResultsProcedures were performed successfully without major complications in 20 dogs. In 2 dogs (German shepherds) with Type III PDA, ACDO placement was unsuccessful; 2 other German Shepherds were excluded from the procedure because their ductal diameters, measured echocardiographically, exceeded the limits of the maximal ACDO size. Two dogs weighing ≤3.5 kg had suboptimal echocardiographic visualization of the PDA and were considered too small for safe ACDO deployment. All intravascular devices at the level of the heart and great vessels appeared hyperechoic on TTE image and could be clearly monitored and guided in real-time.ConclusionsWe have demonstrated that TTE monitoring can guide each step of pulmonic balloon valvuloplasty and PDA occlusion without fluoroscopy.     

Expression of NF-κB,NR2B and iNOS in spinal cord in a rat model of neuropathic pain

AIM: To observe the expression of nuclear factor-kappa B (NF-κB), N-methyl-D-aspartic acid receptor 2B (NR2B) and inducible nitric oxide synthase (iNOS) in the spinal cord in a rat model of chronic constriction injury (CCI) of the sciatic nerve. METHODS: Fifty-six adult male Sprague-Dawley rats weighing 180~220 g were randomly divided into sham group (n=8) and CCI group (n=48). The mechanical withdrawal threshold (MWT) and paw withdrawal latency (PWL) of the hind paws were measured 1 d before CCI and 1 d, 4 d, 7 d, 14 d and 21 d after surgery. The L4~L6 segment of the spinal cord was taken for determining the expression of NF-κB, NR2B and iNOS by RT-PCR and Western blotting. RESULTS: At 1 d, 4 d, 7 d, 14 d and 21 d after surgery, the MWT and PWL in CCI group were obviously lower than those in sham group. The expression of NF-κB, NR2B and iNOS at mRNA and protein levels increased significantly. Positive correlations were found between the mRNA expression of NF-κB and iNOS (r=0.842, P<0.05), and between the mRNA expression of NR2B and iNOS (r=0.833, P<0.05). CONCLUSION: The generation and maintenance of hyperalgesia in sciatic nerve injury rats may attribute to the activation of NF-κB and NR2B and concomitant increase in iNOS.     

锌浸种对黄瓜种子萌发的影响

以黄瓜种子为研究材料,设置了7个锌浸种浓度（0,1,50,100,150,200,250mg／L）,研究了不同浓度的锌浸种处理对黄瓜种子萌发的影响。结果表明,低浓度（0～100mg/L）锌处理对黄瓜种子的萌发有促进作用,在锌的浓度为100mg／L时,其发芽率最大,种子萌发第7天时的单株鲜质量、单株干质量、芽长、根长也达到最大值,且抑制率最低,高浓度（〉100mg／L）锌处理则对种子萌发表现出一定的抑制作用。     

纯香油麦菜常年栽培技术

中国农科院蔬菜研究所生产的纯香油麦菜在七星区穿山乡种植三年多来，该品种适应性强，口感脆香，品质好，市售价高，深受农民和消费者喜爱，现将油麦菜常年栽培技术小结如下。     

栗山天牛成虫的活动节律

研究了栗山天牛Massicus raddei(Blessig)成虫的日活动节律,结果表明,栗山天牛成虫的取食、交配、产卵、爬行和飞翔等行为的昼夜节律均表现为单峰型。其取食的高峰期是在晚上18时至20时;交配高峰期为17时至22时;产卵和爬行的高峰期均为19时至22时;飞翔的高峰期为19时至21时。提出了昆虫活跃值的概念及其计算方法,并应用该方法评价了栗山天牛成虫的群体活跃值,结果表明,栗山天牛成虫的群体活跃值日变化规律亦为单峰型,而且不同时间的活跃值差异极显著,成虫主要在下午16时至晚上24时活动,高峰期是天黑以后的19时至21时。在高峰时段,栗山天牛雌雄成虫的活跃值差异不显著,但部分行为存在较大差异。不同天气条件下栗山天牛成虫的活跃值差异显著,晴天成虫的活力最强,阴天次之,雨天成虫的活动能力最弱,而且全天没有明显的活动高峰期。温度在22℃～26℃、相对湿度在50%～80%时利于天牛成虫的活动。     

玉米新品种丰聊008高产栽培及制种技术

丰聊008是由聊城市种子公司选育的玉米新品种。该杂交种抗病,抗倒伏,适应性强,稳产性好,增产潜力大,活秆成熟,是一个优良的中早熟玉米杂交种。2006年3月通过山东省品种审定委员会审定。     

酵母培养物对饲喂霉变玉米日粮肉仔鸡肠壁结构和肠道菌群影响的研究

选择1日龄健康AA肉仔鸡225只,随机分配到5个处理组中,每个处理3个重复,每个重复15只。5个处理组分别为:基础日粮组、霉变玉米日粮组、霉变玉米+0.15%酵母培养物组、霉变玉米+0.30%酵母培养物组、霉变玉米+0.45%酵母培养物组,研究结果显示,酵母培养物能够有效改善由于食入霉变玉米日粮引起的小肠结构和盲肠菌群数量的负面影响。     

加强农机科技推广项目管理的若干思考

本文对机科技推广项目管理中存在的问题进行了深入剖析,提出了若干改建建议.