丙硫菌唑中间体的合成优化

作为一种新型的三唑硫酮类杀菌剂,丙硫菌唑凭借其广谱的杀菌活性及低毒、安全、环保特性,目前已跃居全球第三大杀菌剂。但是,丙硫菌唑关键中间体的合成阻碍了原药的大量生产,主要对α-乙酰基-α-氯-γ-丁内酯和3,5-二氯-2-戊酮的合成进行了研究和优化,为原药的合成与生产做好铺垫。     

浅析BIM技术在消防泵房机电工程中的应用

为了进一步提高消防泵房中机电安装工程的施工质量,通过借助BIM技术,获得了直观的三维模型,有效的解决了泵房内空间局促引发的线管碰撞、下料不准、频繁拆改等施工难题。     

Study of the key factors affecting the triple grid lifetime of the LIPS-300 ion thruster

In order to ascertain the key factors affecting the lifetime of the triple grids in the LIPS-300 ion thruster,the thermal deformation,upstream ion density and component lifetime of the grids are simulated with finite element analysis,fluid simulation and charged-particle tracing simulation methods on the basis of a 1500 h short lifetime test.The key factor affecting the lifetime of the triple grids in the LIPS-300 ion thruster is obtained and analyzed through the test results.The results show that ion sputtering erosion of the grids in 5 kW operation mode is greater than in the case of 3 kW.In 5 kW mode,the decelerator grid shows the most serious corrosion,the accelerator grid shows moderate corrosion,and the screen grid shows the least amount of corrosion.With the serious corrosion of the grids in 5 kW operation mode,the intercept current of the acceleration and deceleration grids increases substantially.Meanwhile,the cold gap between the accelerator grid and the screen grid decreases from 1 mm to 0.7 mm,while the cold gap between the accelerator grid and the decelerator grid increases from 1 mm to 1.25 mm after 1500 h of thruster operation.At equilibrium temperature with 5 k W power,the finite element method(FEM)simulation results show that the hot gap between the screen grid and the accelerator grid reduces to 0.2 mm.Accordingly,the hot gap between the accelerator grid and the decelerator grid increases to 1.5 mm.According to the fluid method,the plasma density simulated in most regions of the discharge chamber is 1?×?10~(18)-8?×?10~(18)m~(-3).The upstream plasma density of the screen grid is in the range 6?×?10~(17)-6?×?10~(18)m~(-3)and displays a parabolic characteristic.The charged particle tracing simulation method results show that the ion beam current without the thermal deformation of triple grids has optimal perveance status.The ion sputtering rates of the accelerator grid hole and the decelerator hole are 5.5?×?10~(-14)kg s~(-1)and 4.28?×?10~(-14)kg s~(-1),respectively,while after the thermal deformation of the triple grids,the ion beam current has over-perveance status.The ion sputtering rates of the accelerator grid hole and the decelerator hole are 1.41?×?10~(-13)kg s~(-1)and 4.1?×?10~(-13)kg s~(-1),respectively.The anode current is a key factor for the triple grid lifetime in situations where the structural strength of the grids does not change with temperature variation.The average sputtering rates of the accelerator grid and the decelerator grid,which were measured during the 1500 h lifetime test in5 k W operating conditions,are 2.2?×?10~(-13)kg s~(-1)and 7.3?×?10~(-13)kg s~(-1),respectively.These results are in accordance with the simulation,and the error comes mainly from the calculation distribution of the upstream plasma density of the grids.     

国际新趋势 超市中的餐饮

正在超市中开餐饮店?国内好像还少有,但是,在美国和加拿大等地,却方兴未艾,经营红火。混合型食品超市在美国加州,有一家较大型的混合型食品超市,销售着某些类型的海鲜、酒类、饮品、芝士、餐具、酒具等,主要以销售生蚝为多。所谓混合型,就是既有像超市一样自助选取商品,也有柜台式的销售。整个市场少说也有4000平方米。笔者与家人来到了其中一个蚝档。此档长约七八米,宽约3米多,团团围绕着档口的是吧台式光滑的石板,石板前是高高的吧椅,供食客坐着享用美味。堆     

Study on the influence of three-grid assembly thermal deformation on breakdown times and an ion extraction process

In order to study the influence of three-grid assembly thermal deformation caused by heat accumulation on breakdown times and an ion extraction process,a hot gap test and a breakdown time test are carried out to obtain thermal deformation of the grids when the thruster is in 5 k W operation mode.Meanwhile,the fluid simulation method and particle-in-cell-Monte Carlo collision(PICMCC) method are adopted to simulate the ion extraction process according to the previous test results.The numerical calculation results are verified by the ion thruster performance test.The results show that after about 1.2 h operation,the hot gap between the screen grid and the accelerator grid reduce to 0.25–0.3 mm,while the hot gap between the accelerator grid and the decelerator grid increase from 1 mm to about 1.4 mm when the grids reach thermal equilibrium,and the hot gap is almost unchanged.In addition,the breakdown times experiment shows that 0.26 mm is the minimal safe hot gap for the grid assembly as the breakdown times improves significantly when the gap is smaller than this value.Fluid simulation results show that the plasma density of the screen grid is in the range 6?×10~(17)–6?×?10~(18) m~(13) and displays a parabolic characteristic,while the electron temperature gradually increases along the axial direction.The PIC-MCC results show that the current falling of an ion beam through a single aperture is significant.Meanwhile,the intercepted current of the accelerator grid and the decelerator grid both increase with the change in the hot gap.The ion beam current has optimal perveance status without thermal deformation,and the intercepted current of the accelerator grid and the decelerator grid are 3.65 m A and 6.26 m A,respectively.Furthermore,under the effect of thermal deformation,the ion beam current has over-perveance status,and the intercepted current of the accelerator grid and the decelerator grid are 10.46 m A and 18.24 m A,respectively.Performance test results indicate that the breakdown times increase obviously.The intercepted current of the accelerator grid and the decelerator grid increases to 13 m A and 16.5 m A,respectively,due to the change in the hot gap after 1.5 h operation.The numerical calculation results are well consistent with performance test results,and the error comes mainly from the test uncertainty of the hot gap.     

万年县地方志中水文化资料辑录

万年县历史文化悠久,地貌特征为"六山一水二分田,一分道路和庄园",依山傍水,雨水充足,水资源丰富,素有"鱼米之乡"、"贡米之乡"之称。因此,与水有关的水利、人物、水景、井潭、水信仰、谚语等水文化资料比较多,故选择一些典型的水文化资料辑录下来,以供专家学者解读。     

电解铝废渣提锂方法研究

随着新能源汽车行业进入黄金发展期，动力锂电池行业呈爆发式增长，碳酸锂的需求量也逐年递增，含锂氟化盐的使用造成大量含锂电解铝废渣产生，如果得到合理回收利用，将有利于缓解新能源产业带来的用锂压力。重点研究了以含锂电解铝废渣和浓硫酸为原料，通过酸浸取等一系列工艺，制备电池级碳酸锂，同时副产冰晶石，并从实验原理、实验方法、工艺关键点控制、产品质量、工艺特点等方面进行了深度剖析。本工艺具有良好的社会效益、经济效益和环保效益，易于推广应用。     

潞安矿区煤田钻井造浆土实验研究

针对潞安矿区煤田钻探造浆用土进行了室内实验测试与分析,通过造浆率的测试和造浆改性实验,得出其造浆率极低、利用常规的方法不能调节现场造浆土造浆性能的结论;实验研究了现场造浆土的矿物成分、粒度成分及其造浆后的失水量、胶体率和比重,得出现场土不适合作为泥浆造浆用土,进而对潞安矿区煤田钻孔造浆土进行了推荐。     

激光陀螺用阴极基底的反挤压制备工艺

阴极基底是激光陀螺关键部件,属薄壁碗型金属件,目前主要采用棒料切削加工制备,不仅材料利用率低,而且棒料切削加工把金属内部的纤维组织割断[1,2],降低了阴极基底的性能,特别是对阴极基底气密性影响较大.反挤压工艺在压制过程中材料处于三向高压应力应变状态,挤压件内部孔洞等缺陷充分减少,纤维组织完全沿表面均匀平行排列,可以极大地提高挤压件的气密性,使材料组织得到细化和强化,力学性能提高.因此,本文尝试采用反挤压法制备阴极基底.     

关于热电厂锅炉的节能措施分析

随着能源消耗的日益加剧，能源危机笼罩着全世界绝大多数国家，我国也不能幸免，近几十年来，我国的经济高速发展，可是付出的代价是能源的急速消耗以及环境的严重破坏。其中热电厂是耗能、排污严重的产业之一，文章分析了热电厂锅炉的耗能问题，对如何做好节能措施提出了建议。