切屑卷曲的力学分析及其应用

在试验和理论分析的基础上，本文提出了复合卷曲的切屑比向上卷曲的切屑、当侧卷程度较大时比例向卷曲的切屑易于折断的观点，并且讨论了切屑产生复合卷曲及侧向卷曲的条件，这些对断屑槽的设计和使用有重要意义。     

Influence of death struggle on the structural changes in chub mackerel muscle during chilled storage

ABSTRACT: Chub mackerel (34–35 cm, approximately 500 g), which were caught by fishing with a rod and line at the Bungo Channel, Oita prefecture, were rested overnight in a fish preserve and either killed by decapitation (control group) or allowed to struggle in air for 30 min (struggled group). Muscle samples were excised every 4 h, and measurements on breaking strength and histological observations were done for both groups. The breaking strength of muscle in the control group was significantly higher than that in the struggled group, whereby a decrease in breaking strength was delayed for 12 h compared to the struggled group. Light microscopy showed space extension among muscle cells in association with a decrease in breaking strength. Especially in the struggled group, the extended area was larger and the difference in area was significant at the time when breaking strength showed a significant difference. Using electron microscopy, the extended area showed cut and/or disappeared collagen fibrils. From these results, it was demonstrated that struggling to death promoted the degradation of collagen fibrils and the weakening of connective tissue and, resultantly, led to the faster softening of muscle of chub mackerel.     

工业氟污染对山羊硬组织损害的研究

40只6～10月龄本地山羊在氟重污染牧场放牧18个月,对逐月牧草水溶氟,不同时期骨氟、枯草期血钙及碱性磷酸酶作了测定。同时应用X射线及扫描电镜对下颌、肋骨与牙齿结构作了观察。结果指出,随着骨氟增加,血钙降低、碱性磷酸酶升高、骨皮质变薄、密度降低、骨表面疏松多孔,牙齿磨灭不齐、钙化不良、釉质与本质结构改变。干早气候是枯草期牧草氟升高的先决条件,枯草期牧草高氟与钙的负平衡是形成骨质疏松的主要原因,而青草或与枯草期牧草氟含量及动物缺钙程度的不同是引起牙齿磨灭不齐、缩短寿命的关键因素。     

应用超声波破碎苏云金芽孢杆菌试验

用超声波对一定浓度的苏云金芽孢杆菌的营养细胞和芽孢进行破碎试验,结果表明:在试验条件下,超声波破碎达到95%以上的破碎率所需时间为30~50min,尤其是菌液浓度为每毫升50亿,用Φ10变幅杆破碎,40min破碎率可达99.9%。而细菌的芽孢,无论是采用幅杆Φ6或Φ10,其破碎效果不明显。     

秸秆饲料青切揉碎机的设计

根据我国畜牧业发展和秸秆饲料利用现状,研究设计了一种大型、高效秸秆饲料加工机械.该机采用直抛滚筒式切碎装置,增设了对作物秸秆和散干牧草的揉搓作用的击碎和揉碎部件,物料加工质量大大提高.喂入装置采用先进的摆臂浮动辊式喂入机构,性能可靠;同时,增加了牵引机构,可实现流动作业.动力可选配18.4kW柴油机或18.5kW电动机.     

Effects of CSF-1,IL-1α on CSF-1 receptor gene expression in rat dental follicle cells

AIM: To study the effects of colony stimulating factor(CSF-1) and IL-1α on CSF-1 receptor mRNA levels and to determine if the autocrine effect is inhibited through the CSF-1 receptor.METHODS: Rat dental follicle cells were cultured in vitro.The effects of different concentrations of CSF-1 and IL-1α on CSF-1 receptor gene expression were detected by means of RT-PCR.RESULTS: High concentrations of CSF-1 reduced the gene expression of the CSF-1 receptor. IL-1α had no effects on CSF-1 receptor mRNA levels.CONCLUSION: High concentrations of CSF-1 inhibit the expression of CSF-1 receptor.IL-1α has no effect on the expression of CSF-1 receptor mRNA.     

Analysis of mesh breaking loads in cotton gill nets: Possible solution to ghost fishing

ABSTRACT:   A small number of fishers in Chiba Prefecture of eastern Japan use cotton gill nets to catch Japanese spiny lobster Panulirus japonicus. To examine the advantages of cotton gill nets, we analyzed changes in mesh breaking load of a new cotton gill net used in a fishing operation. A new cotton gill net was also soaked in a seawater tank to simulate ghost fishing conditions. The average mesh breaking load of new cotton mesh was 50.3 N. This value decreased to 19.0 N after 38 days (∼912 h), and after 82 days (∼1968 h) the mesh could be easily torn (breaking load 0.07 N). Under fishing conditions, the cumulative soak time was only 744.4 h over 19 months. The average breaking load at the end of this period was 43.1 N, a strength 86% that of the presoaked mesh. The mesh breaking load of a cotton gill net continuously soaked for 744.4 h was 26.1 N, as estimated from tank experiment data. Thus, a cotton gill net maintains reasonable strength under typical use conditions, but will degrade if lost at sea.     

巴旦木分级破壳机设计与试验

为解决巴旦木破壳机械生产效率低、破壳率低和核仁损伤量大等问题，通过研究坚果破壳原理，选用适宜机械加工的大巴旦木（‘莎车3号’）为研究对象,设计了巴旦木分级破壳机，同时进行巴旦木尺寸、破壳力加载方向及加载速度、巴旦木含水率的物料特性分析。结果表明：破壳机破壳辊间隙和含水率对巴旦木破壳力和变形量影响显著。使用试验法优化了巴旦木分级破壳机构工作参数，当两轧辊间距离调整为Ⅰ级14 mm、Ⅱ级13 mm和Ⅲ级12 mm，含水率控制在9.8%～10.5%范围内，转速为1 000 r·min^-1时，测得平均破壳率为95.57%，平均破损率为3.37%，满足实际生产需求。     

机床误差对螺旋锥齿轮齿形的影响规

基于螺旋锥齿轮齿面分析的数学模型,采用最优化算法和一种新的计算齿形误差的方法,计算了误差齿面与理论齿面在理论齿面法线方向的齿形误差.通过引入机床调整误差和刀具参数误差,分析了各种误差对螺旋锥齿轮齿形的影响规律,以图形的方式表示了误差齿面相对于理论齿面的偏离方向以及误差值的大小,为机床的精度设计、齿形误差的修正以及指导实际加工提供了理论依据.通过实际的磨齿加工和检测对算法以及分析结果进行了验证.     

退化人工梭梭林的恢复技术研究

对退化人工梭梭林进行恢复试验研究发现:滴灌可使梭梭林地土壤含水率显著提高;梭梭光合作用增强;群落物种数增多,盖度增大;防风固沙作用增强.布设机械沙障可使退化梭梭林地表粗糙度增大,林内近地面层风速、输沙量显著下降.春灌3 a后,不仅退化梭梭个体恢复正常生长,同时梭梭林群落物种组成数明显增加,盖度显著增大,生态功能也逐渐恢复.雨水集流和雨水下渗改造两种模式应用1～2 a后,退化梭梭林地土壤含水率均有明显提高.滴灌、布设机械沙障、春灌和改造结皮4种技术措施对退化梭梭林生长及其环境均有明显的恢复作用,其中滴灌、机械沙障恢复技术是当前和今后推广的主要措施;春灌和改造结皮可作为前两种技术的补充措施.