摘要：In order to ensure overall optimization of the underground metal mine production scale, multidisciplinary design optimization model of production scale which covers the subsystem objective function of income of production, safety and environmental impact in the underground metal mine was established by using multidisciplinary design optimization method. The coupling effects from various disciplines were fully considered, and adaptive mutative scale chaos immunization optimization algorithm was adopted to solve multidisciplinary design optimization model of underground metal mine production scale. Practical results show that multidisciplinary design optimization on production scale of an underground lead and zinc mine reflect the actual operating conditions more realistically, the production scale is about 1.25 Mt/a (Lead and zinc metal content of 160 000 t/a), the economic life is approximately 14 a, corresponding coefficient of production profits can be increased to 15.13%, safety factor can be increased to 5.4% and environmental impact coefficient can be reduced by 9.52%.

摘要：New empirical formulas of the transmission coefficient for permeable breakwaters were suggested based on available experimental data regarding the low-crest structure （LCS）, including the permeable rubble mound breakwater and pile-type breakwater. The rationality of the present formulas was verified by their comparison with existing empirical and analytical formulas. Numerical flume results were obtained by solving the modified Boussinessq-type wave equations （MBEs）, and a new expression relating the friction coefficient of to the relative submerged depth Rt/H8 was also derived. Comparative analysis shows that the results of the present formulas agree with the numerical flume results as well as available experimental data, and the present formulas are superior to the existing empirical and analytical expressions in estimating the transmission coefficient. The present formulas can provide references for estimation of the transmission coefficient in engineering practice.

摘要：An optimal drainage tunnel location determination method for landslide prevention was proposed to solve the existing problems in drainage tunnel construction. Current applications of drainage tunnel systems in China were reviewed and the fimctions of drainage tunnel were categorized as catchment and interception. Numerical simulations were conducted. The results show that both catchment and interception tunnels have variation of the function in the simulation of monolayer model, which shows the reduction of permeability condition in lower layer. The function of catchment can be observed in the deep slope, while the function of interception is observed near groundwater source. By using the slope safety factor and discharge water amount as the objectives of optimal drainage tunnel location, and pore-water pressure in fixed node and section flux as the judgment for construction quality of adjacent drainage tunnel, the design principle of drainage tunnel was introduced. The K103 Landslide was illustrated as an example to determine the optimal drainage tunnel location. The measured drainage tunnel efficiency was evaluated and compared with that from the numerical analyses based on groundwater data. The results validate the present numerical study.

摘要：目的:探索长时间停流情况下高扬程虹吸管中空气累积现象的发生发展及其对虹吸持续工作的危害,并给出应对该现象的工程预防措施。创新点:利用物理模型实验,结合理论解析推导,得到高扬程虹吸管内空气累积的原因及关键影响因素,突破高扬程虹吸排水在少雨地区的使用局限,给出其长期适用的工程设计条件,对其在实际边坡工程中的推广应用提供理论技术指导。方法:通过物理模型试验,揭示长期停流虹吸管内出现空气累积的必然性;利用理论公式推导,对不同因素的影响结果进行对比分析,得出影响空气累积的主要因素。结论:1.溶于水的空气因压力降低而析出、管端空气溶入扩散到虹吸管顶部及温度变化引起空气析出等现象是无法避免的;其中,原有空气的析出及温度变化引起的空气累积是主要因素;2.边坡虹吸排水设计时进水端口距控制水位至少应预留2.05 m的地下水位上升余量,或者保持出水口的高程比进水口高程低4.1 m来保证析出空气段处于下水管中。

摘要：Precision planting is one key point of precision agriculture.A doorframe type swing seedling pick-up device for the automatic precise field transplanter was designed and tested in a *** seedling device could automatically extract seedlings from growing trays,transfer them,and release them into the planting unit where they were to be precisely transplanted into the *** consisted of a path manipulator and two *** path manipulator for seedling extraction was constructed with creative design ofⅡ-type mechanism combination in *** consisted of an oscillating guide linkage mechanism and a grooved globoidal cam *** to the planned seedling pick-up trajectory,the design of the path manipulator for seedling extraction was finished with a set of the closed loop vector *** gripper was a pincette-type mechanism using the pick-up pins to penetrate into the root mass for seedling *** consisted of multiple pick-up pins,U-type pull rod,shaft,stop block,compression spring and *** mechanical dimensions of the gripper were determined by the tray size and plant characteristic with a set of rectangular equations and the boundary constraint *** final gripper was developed on the basis of cultural practice for vegetable seedling in China.A prototype of the seedling pick-up device was constructed to examine whether its working efficacy was satisfactory or *** to the analysis on the work process,the seedling pick-up device could precisely complete a work cycle of approaching,penetrating,extracting,transferring,erecting and discharging a *** pepper seedlings,tomato seedlings and cucumber seedlings as the transplanting objects,the performance tests were conducted to evaluate the practicality and adaptability of the pick-up *** laboratory evaluation showed that the pick-up device equipped with two grippers could extract 70 seedlings per minute with an average success ratio of 90.49%.T

摘要：目的 对国产可植入式自悬浮心室辅助装置(national implantable ventricular assist device,NIVAD)进行体外实验研究,评价溶血性能和耐疲劳稳定性.方法 将NIVAD安置于自行设计的体外测试平台中,充满新鲜抗凝猪血2 500 ml,设定血泵转速8 000转/min,后负荷100 mmHg(1 mmHg=0.133 kPa),流量3.5 L/min,恒温37℃,转泵前、后多个时间点取血样本测量游离血红蛋白(FHB),同时留置静置血液为对照组,分别计算血泵标准化溶血指数(NIH).疲劳实验将血液换为纯净水,条件不变,连续记录90天泵的各项参数.结果 与对照组相比,实验组FHB增高,NIVAD的NIH值为(0.0052±0.0019) mg/L.疲劳实验中血泵连续正常运转90天,运行平稳,各项参数稳定.结论 NIVAD血泵对血液有一定的破坏,但在允许范围之内,与国内外同类产品相比,具有一定优势,同时有较好的耐疲劳能力.

摘要：目的研究放宽独生子女政策和降低剖宫产率政策会如何影响中国剖宫产率和围产儿及孕产妇死亡率。研究设计观察性研究。研究地点全国危重孕产妇医院监测系统。研究对象2012--2016年，全国危重孕产妇医院监测系统的438家医院中，妊娠28周及以上或出生体重≥1000g的6838582例围产儿。主要结局指标使用修改的Robson分类定义产科风险。主要结局指标包括：产次、产妇年龄和Robson分类的分布变化；每个风险类别中，剖宫产率随时间变化的原始和调整趋势（使用稳健方差估计的泊松回归）；同期围产儿及孕产妇死亡率随时间变化的趋势。结果剖宫产率在20122016年稳步下降（原始相对风险0．91，95％可信区间为0．89～0．93），在2016年总的剖宫产率达到41．1％。放宽独生子女政策伴随着经产妇生育比例的上升（从2012年的34．1％到2016年的46．7％），有既往剖宫产史的妇女的分娩量几乎翻了一番（从9．8％到17．7％）。在控制了这些影响因素后，剖宫产率随时间下降的趋势更大（调整后的相对风险0．82，95％可信区间为0．81～0．84）。初产妇的剖宫产率明显下降（0．75，95％可信区间为0．73～0．77），但无既往剖宫产史的经产妇的剖宫产率也有所下降（0．65，95％可信区间为0．62～0．77）。下降幅度最明显的是2012年剖宫产率最高的医院，这与政府针对剖宫产率最高的医院实行的政策是一致的。同期围产儿死亡率从每千出生10．1降至7．2（0．87，95％可信区间为0．83～0．91），而孕产妇死亡率没有变化。结论中国是唯一一个成功扭转剖宫产率上升趋势的国家。放宽独生子女政策相关的产科风险变化将增加剖宫产需求，考虑这一因素，中国的成功显得尤为显著。中国的经验表明，当政策能全面、系统地控制导致剖宫产过度使用的因素，再结合临床实践中各种激励措施，就能够改变剖宫产持续上升的趋势。