Seismic behavior of reinforced-concrete and steel reinforced concrete ultra short columns

进行了4个钢筋混凝土(RC)超短柱、4个型钢混凝土(SRC)超短柱和6个RC分体柱的滞回性能试验研究.8个超短柱的剪跨比为1;6个分体柱的剪跨比为2.4.试验结果表明,RC超短柱的变形能力不满足现行抗震规范要求.不设剪力连接件的SRC超短柱的破坏模式为黏结破坏,与RC超短柱相比,其抗剪承载力和变形能力并无明显提高;设置剪力连接件的SRC超短柱的破坏模式为斜压破坏,其抗剪承载力和变形能力显著提高,但构件的变形能力仍然难以满足现行抗震规范要求.试验结果还表明,在RC超短柱中开缝,形成剪跨比大于2的RC分体柱,可有效提高柱子的延性和变形能力.对于RC分体柱,随轴压比的提高,构件的抗弯承载力提高,但延性和变形能力下降;当设计轴压比大于0.7时,RC分体柱的变形能力不满足现行抗震规范要求.根据试验结果,提出了SRC超短柱的剪力连接件设计方法和RC分体柱的设计建议.     

低温保存萨福克种公羊鲜精效果研究

肉用种公羊鲜精低温(2～5℃)保存,是根据精子的代谢活动随着温度的降低而逐渐减弱,当降至10℃以下时基本受到抑制的特点,延长鲜精的利用时间。2009年8月16日与22日,分2次在吉林省长岭县14号种羊场,对6头萨福克纯种肉用种公羊采精后作低温保存技术处理,用处理后的鲜精进行24、48 h活力评定,按五级评分法,活力均达4～5分。选择90只东北细毛羊2岁母羊经同期发情处理后进行人工授精,受精率达60.61%～63.63%。     

Diludine对夏洛来种公牛精液品质和生产性能的影响研究

试验选用16头夏洛来种公牛,研究了diludine对种公牛体增重,精液品质及生产性能的影响,结果表明diludine不会显增加公牛体重,进而影响生产;diludine能显提高精液活率,精液量及冻精产量。     

控制光照对非繁殖期种公鹅睾丸形态和组织学结构变化的研究

本试验通过遮光控制自然光照,对非繁殖期种公鹅的睾丸形态及组织学结构变化的研究,以求了解光照值与鹅生殖腺发育的关系,目的在于为制定广东鹅的反季节生产措施提供科学依据。试验结果表明:在正常繁殖期初期和繁殖期高潮,控制光照对试验组和对照组的睾丸形态、重量和精细管中精子的呈现度,其差异不显著;在作繁殖期控制光照,试验组和对照组在睾丸的形态、重量和精细管中精子的呈现度等方面均有良好的效应,其差异极为显著。     

A cross-sectional survey of Thoroughbred stud farm management in the North Island of New Zealand

AIM: To obtain initial baseline data on the management of Thoroughbred stud farms in the North Island of New Zealand.

METHODS: Data on the management of Thoroughbred stud farms were collected from a sample of 22 stud farms located in the south Auckland/Waikato region (n=15) and lower North Island (n=7) of New Zealand, using a face-to-face survey. The studmaster provided information on the size, scope and management of the farms during the 2004/2005 breeding season. Analysis was based on the location of the farm and size of the breeding operation (number of resident mares).

RESULTS: Effective farm size ranged from 20 to 526 ha and averaged 167 (standard error (SE) 36) and 88 (SE 49) ha in the south Auckland/Waikato and lower North Island areas, respectively. Some farms in the Auckland/Waikato region stood shuttle stallions. The median number of stallions per farm was three (range 0.9), and the median mare-to-stallion ratio was 43 (range 10.250). The farms had a mean of 50 (range 7.180) wet mares and 21 (range 0.100) dry mares. The number of mares per breeding stallion increased with increasing size of breeding operation (p=0.04), being 28 (95% confidence interval (CI) = 10.56) vs 40 (95% CI=16.74) vs 74 (95% CI=44.113) for moderate (≤70 mares), medium (90–199 mares) and large (≥200 mares in total) operations, respectively. Seventy-one percent of farms aimed to breed dry mares early in the breeding season, and used a combination of lights, hormone therapy, and rising plane of nutrition to achieve this.

Foaling took place in foaling paddocks monitored using a night foaling attendant (17/22) or with foaling alarms (5/22). At birth, 17/22 studmasters routinely administered antibiotics, 14/22 administered tetanus antitoxin, 9/22 administered an enema to foals, and 2/22 did not routinely administer prophylactic treatments. Weaning occurred at 5 (range 3.7–7) months of age, and foals were confined to a box for 1–2 weeks on 16/22 farms. Weaned foals were drenched with anthelmintics every 7 (range 4–9) weeks, and were fed 2.9 (range 1–6) kg of concentrate feed while at pasture until intensive management associated with preparation of the horses for auction began 13 (range 6–20) weeks before the yearling sales. Eight farms weighed the weanlings, at least monthly, to monitor growth.

CONCLUSIONS AND CLINICAL RELEVANCE: The management of Thoroughbred horses was relatively consistent throughout the regions surveyed. Utilisation of breeding stallions tended to be more efficient on the larger stud farms in the south Auckland/Waikato region. Even though foals are grown at pasture they are often provided with large quantities of concentrate feed.     

基于钉刺式残膜回收机中起膜铲的设计分析

对钉刺式残膜回收机的关键部件(起膜铲)进行了详细设计,对起膜铲的3种铲柄进行了受力分析,得知倾斜式铲柄和弯曲式铲柄比直腿式铲柄受到的阻力要小;倾斜式铲柄与弯曲铲柄的受力大小主要和本身倾斜角度有直接关系。同时,对起膜铲的铲刀进行了受力分析,得出铲刀的倾斜角度大导致起膜铲所受到的阻力大的结论。     

青海三角城种羊场草场硒的季节变化及其盈缺分析

经过对青海省三角城种羊场夏(6月中旬)、秋(9月中旬)、冬(12月中旬)三季的水、土壤、牧草、绵羊被毛、血液、组织器官及粪中硒的含量进行调查分析,结果表明,三角城种羊场夏季土壤和牧草严重缺硒;绵羊血浆硒浓度全年均属正常;肝硒浓度低于临界水平;粪硒浓度冬季低于0.1mg/kgDM的正常值;被毛硒则在夏秋两季稍高,冬季严重缺乏,仅为0.012 mg/kg,极显著的低于羊毛缺硒值0.079 mg/kg(P<0.01).     

对10个棉花杂交组合竞争优势研究

为了利用杂种优势选择杂交棉新品种,通过3重复随机区组试验设计,对10个杂交组合从农艺性状、产量、品质等方面与对照（赣棉杂1号）进行杂种优势分析.结果表明：大部分材料在株高、始果枝着生节位、果枝数、单株成铃、衣分、霜前花率、产量等性状方面表现负向竞争优势,而在始果枝着生高度、单铃重、比强度、纤维长度、整齐度等方面表现正向竞争优势;根据育种目标综合评定,组合1和3为优良组合.     

农科大学生的集体心理教育

心理教育是全面发展教育的基础和核心,是新世纪对人才培养的要求,开展集体心理教育是进一步加强大学生心理教育的需要,集体心理教育的实施有赖于心理教育课程的开设,同时还要建立相应的保障系统。     

青年人原发性肝癌致病因素配对病例对照研究

目的：调查湛江市青年人原发性肝癌（ＰＨＣ）的病因。方法：对１２０例青年人原发性肝癌患者采用病例－对照研究。结果：湛江市青年人原发性肝癌与乙型肝炎病毒（ＨＢＶ）感染密切相关,ＨＢＶ总感染率为７９．５％,明显高于对照组１９．５％（Ｐ〈０．０１）。肝癌家族史、肝炎史、饮水、饮酒为青年人原发性肝癌主要危险因素。结论：ＨＢＶ感染在青年人肝癌中的作用远远高于其他危险因素。