Design,fabrication,and cold test of an S-band high-gradient accelerating structure for compact proton therapy facility

An S-band high-gradient accelerating structure is designed for a proton therapy linear accelerator(linac)to accommodate the new development of compact,singleroom facilities and ultra-high dose rate(FLASH)radiotherapy.To optimize the design,an efficient optimization scheme is applied to improve the simulation efficiency.An S-band accelerating structure with 2856 MHz is designed with a low beta of 0.38,which is a difficult structure to achieve for a linac accelerating proton particles from 70 to 250 MeV,as a high gradient up to 50 MV/m is required.A special design involving a dual-feed coupler eliminates the dipole field effect.This paper presents all the details pertaining to the design,fabrication,and cold test results of the S-band high-gradient accelerating structure.

Numerical Calculations and Cold Tests for Flow Fields of a 220t/h Retrofitted Oil-Boiler

In this paper, cold simulation experiments and numerical calculations are conducted to predict 3 D flow field aerodynamics for an oil furnace after being retrofitted due to its fuel variation. K ε model and SIMPLE program under body fit coordination (BFC) system, in which TTM non orthogonal method is used to control the irregular geometric boundary, are adopted to solve the control equations. Model tests are conducted to check the calculation results, showing that they are in agreement with each other. Three different alternatives with different side window locations are also calculated to optimize the designs. The field retrofitting results show that the combination of cold tests with numerical calculations has prosperous application in retrofitting or renewing medium and small boilers.

Metal and Composite Intermodal Containers in Comparative Cold Tests with Wood Chips

Intermodal containers have many advantages in the bulk supply chain, but idle times may cause freezing problems for containers in terminals and long-lasting deliveries, especially during the winter time in Nordic conditions. The aim of the cold tests was to study metal and composite containers’ ability to tolerate wood chips freezing into the inner surface of the container. Two of the containers were normal metal containers and one was a composite container. The loaded containers were put inside the laboratory hall, the temperature of which was -30°C, and kept there for variable times: less than 24 hours. The inner surface of one of metal containers was treated with a special coolant, EC1. After the test, the chips were unloaded, and the container walls were checked to determine whether there was any material left on them. The test results indicated the advantages of composite containers having a thermally insulated structure without freezing problems. At the same time, chips were freezing badly onto the floor of both metal containers. A frozen chip layer with a thickness of approximately 50 cm - 60 cm was stuck to the floors. As such, EC1 did not seem to prevent the freezing of the chips onto the inner surfaces. The results proved that intermodal logistics of truck and train transportation would be more suitable for composite containers than for metal containers in the winter time in Nordic conditions.

Design and cold test of a rectangular cavity beam position monitor

The CBPM is a kind of monitor which is used for the measurement of beam transverse position. It is becoming increasingly popular due to its high potential in resolution performance. In theory, the resolution can reach about 1 nanometer. In this paper, a rectangular CBPM is designed for it has better X-Y isolation than a cylindrical one. It has been simulated and measured, and the results agree with each other very well. The procedures and results for the simulation and the cold test will be shown later and it will be proved that this is a reliable method for the CBPM design.

Design optimization and cold RF test of a 2.6-cell cryogenic RF gun

To further improve the performance of acceler-ators,the first cryogenic normal-conducting RF gun in China was designed and manufactured.As a new and attractive trend,this optimized cryogenic RF gun can generate a low-emittance beam with a short-driven laser pulse because of its promising high gradient on the cath-ode.In this paper,optimization of the RF design and beam dynamics,including suppression of the peak RF field and elimination of the multipole mode,is presented.In addi-tion,the emittance growth caused by the alignment devi-ation and RF jitter is discussed.After the gun was manufactured,a cold test was conducted at both room temperature and cryogenic conditions.At room tempera-ture,the field distribution was obtained by the bead pull method.Under cryogenic conditions,the RF properties,such as the coupling coefficient and quality factor,varied with temperature.The test results agreed with the design.In the cryogenic test,vibration measurements were performed.Without vibration isolation,a maximum vibration of 50 lm was observed.These cold test results are the basis of the following high-power test.

Design and cold test of S-BAND cavity BPM for HLS

An S-band cavity BPM is designed for a new injector in National Synchrotron Radiation Laboratory. A re-entrant position cavity is tuned to the TM110 mode as position cavity. Cut-through waveguides are used as pickups to suppress the monopole signal. Theoretical resolution of this design is 31 nm. A prototype cavity BPM system is manufactured for off-line cold tests. The wire scanning method is used to calibrate the BPM and estimate the performance of the on-line BPM system. A cross-talk problem has been detected during the cold test. Racetrack cavity BPM design can be used to suppress the cross-talk. With the nonlinear effect being ignored, transform matrix can be used to correct cross-talk. Analysis of cold test results shows that the position resolution of prototype BPM is better than 3 μm.

Model test study of frost heaving pressures in tunnels excavated in fractured rock mass in cold regions

Based on the similarity theory, taking the horseshoe, city-gate and round linings as examples, the value and distribution regularities of normal frost heaving pressures （hereinafter as frost heaving pressures） in tunnels excavated in fractured rock mass in cold regions under different constraints and freezing depths were studied by a test model. It was found that the larger the frozen depth, the larger the frost heaving pressure, and the stronger the top constraint, the larger the frost heaving pressure. For the horseshoe lining and city-gate lining, the top constraint has a greater effect on the frost heaving pressures on the arch and the inverted arch. For the round lining, the influences of the top constraint on the frost heaving pressure in all linings are almost the same. The frost heaving pressure is maximum on the city-gate lining and minimal on the round lining. The largest frost heaving pressure all occur near the foot of the inverted arch for the three kinds of lining. Thus, the test data basically coincide with the observed in situ data.

A Review of the Methods of Identifying and Testing Plant Cold Resistance

Low-tempemture stress is a major abiotic stress influencing plant growth, economic yield and quality worldwide. Precise and reliable identification and test of plant cold resistance is a foundation for exploring low-temperature damages, cold resistance mechanism of plants, cultivating and innovating quality cold-re- sistant germplasm resources, which is rather important for woody plants because their perennial and large-sized characteristics. Generally, most researches on plant cold-resistant physiology focused on identification and utilization of cold resistance worldwide, and a few on test methods of cold resistance, but cold resistance mechanism has been less reported. Therefore, researches on methods of identifying and testing plant resistance have achieved considerable progress, accumulated much experience and formed characteristics gradually in terms of methodology. Current methods of identifying plant cold resistance include open field/outdoor culti- vation evaluation, cold and frost damage investigation, simulated cold weather, and mathematical model forecast. And the methods of testing plant cold resistance include growth condition test, frozen index investigation, electrolyte leakage, bioelectrical impedance mapping and so on. Synthesizing the methods of identifying and testing plant cold resistance should be a key matter in the present and future researches and application of plant cold resistance physiology, improvement and in- novation of the identification and test will be an important direction of the future researches. Identification and test of plant cold resistance based on genomies, meta- bonomics and proteomics should be the new trend of the researches on physiology and ecology of plant cold resistance.

Oblique Y-groove cracking test of the welding cold cracking susceptibility of domestic X-70 pipeline steel

Gas Transmitting From West to East Project' is significant. It should ensure the welding quality and safety of pipeline. The task is very arduous to guarantee the quality of the project in the condition of long line, complex weather and geology features. In this paper, the welding cold cracking susceptibility of domestic X 70 pipeline steel adopted by the project, which is one of the most interesting questions of welding quality about petrol pipeline, was studied by means of oblique Y groove cracking test. The crack ratio of surface and section was tested under the conditions of different welding materials and preheat temperature .The thickness of plate steel was 14.7 mm and 10.3 mm . The results reveal that X 70 pipeline steel has good crack resistance. The research has important value for the construction of large scale pipeline engineering and the application of domestic X 70 pipeline steel.

Resistance and Reactance of Monopole Fields Induced by a Test Charge Drifting Off-Axis in a Cold and Collisional Cylindrical Plasma

We study the interaction of a uniform, cold and collisional plasma with a test charged particle moving off-axis at a constant speed down a cylindrical tube with a resistive thick metallic wall. Upon matching the electromagnetic field components at all interfaces, the induced monopole electromagnetic fields in the plasma are obtained in the frequency domain. An expression for the plasma electric resistance and reactance is derived and analyzed numerically for some representative parameters. Near the plasma resonant frequency, the plasma resistance evolves with frequency like a parallel RLC resonator with peak resistance at the plasma frequency pe, while the plasma reactance can be capacitive or inductive in nature depending on the frequency under consideration.

流化床反应室内铁矿石的临界流化特性

U型反应室是悬浮焙烧装备的核心部件,明确其内物料的临界流化特性具有理论与实践意义.为此,自行搭建了冷态试验系统,并以赤铁矿粉、氧化铝粉为原料,研究了松动风量、物料性质对物料临界流化特性的影响规律,并对原有经验公式进行了修正.结果表明:临界流化气速随物料粒度、密度的增加而增加;在松动室床层为固定床的条件下,临界流化气速随松动风量的增大而减小;修正后的过程方程与试验数据吻合较好,可用于反应室内物料流化行为的预测.研究结果利于悬浮磁化焙烧技术实体化,对该技术工业应用具有一定的指导意义.

The Theoretically Studies and Field Testing of Self-Insulation Exterior Wall in the Hot Summer and Cold Winter Zone

The energy efficiency design of the exterior wall in the buildings of the hot summer and cold winter zone of China should consider the heat prevention in summer and the heat insulation in winter. The self-insulation of the exterior?wall is a more feasible design to satisfy the energy efficiency of buildings in the?zone. However, the systematic research is urgently needed for the self-insulation of the exterior wall in the hot summer and cold winter zone of China. The paper tested the thermal performance of the common non-clay materials such as shale sintered hollow brick, sand autoclaved aerated concrete block, etc. by means of indoor experiments. The energy efficiency effect of the common materials was verified using dynamic calculation soft PKPM and several constitutions of exterior wall with different main bricks and insulation materials on the heat bridge were simulated, too. Besides, the tests of the thermal performance of exterior wall in real constructions were carried out to testify the practical effect of the recommended constitutions of exterior wall with different main bricks and insulation materials on the heat bridge. The conclusions are: the physical and thermal properties of the six non-clay wall material are better than the clay porous brick;the thermal performance of the non-clay brick can be improved obviously through the rational arrangement of the holes;shale sintered hollow brick after increasing the holes and rationalizing the hole arrangement and sand autoclaved aerated concrete block are recommended for buildings in the hot summer and cold winter area of China. The dynamic calculation results show that the thermal performances?of the non-clay materials are all satisfied with the energy efficiency;The heat transfer coefficient of the exterior wall with composition?③,?in which?the main wall was sand autoclaved aerated concrete block and the material on the heat bridge was sand autoclaved aerated concrete plate, is the smallest among the three recommended compositions.

不同葡萄砧木抗寒抗抽干能力比较研究

[目的]气候变化新形势下,进一步筛选适宜西北地区抗寒、抗抽干葡萄砧木品种,可为葡萄免埋土栽培推广提供理论依据和技术支撑。[方法]本文以41Bmgt、Riparia、420Bmgt、101-14、196-17、44-53ma、110R、Rupestris du Lot、SO4、161-490、1103P、5BB、3309、Leon Millt共14种13年生葡萄砧木为试材,通过测定离体一年生枝条累计失水速率,结合田间调查葡萄砧木存活率和离体一年生枝条抽干率,以此来评价不同葡萄砧木品种抗抽干能力;结合前人研究及砧木品种特性,采用高低温交变试验箱模拟低温的方法,设置4(对照)、-15、-20、-25和-30℃一系列温度梯度水平,测定不同葡萄砧木一年生枝条相对电导率、丙二醛、游离脯氨酸、可溶性糖及可溶性蛋白5个生理生化指标,利用隶属函数法进行综合评价不同葡萄砧木的抗寒性。[结果]不同葡萄砧木的抗抽干能力由强到弱依次为:3309>161-490>196-17>Leon Millt>420Bmgt>44-53ma>Riparia>110R>1103P>SO4>101-14>41Bmgt>5BB>Rupestris du Lot;随着处理温度的降低,不同葡萄砧木枝条的抗寒指标总体呈现上升趋势,但不同品种之间存在差异。根据隶属函数的综合分析,结果显示各葡萄砧木的抗寒性由强到弱依次为:SO4>196-17>Leon Millt>5BB>Riparia>44-53ma>420Bmgt>1103P>3309>110R>Rupestris du Lot>101-14>41Bmgt>161-490。[结论]Riparia、196-17、44-53ma和Leon Millt具有较强的抗抽干能力和抗寒性,可作为我国西北地区免埋土葡萄砧木使用。

测试条件对水流量平板法测试的热导率的影响

利用水流量平板法测试的热导率的公式确定了影响测试结果的试验参数,通过试验验证了中心量热器单位时间水流量和试样冷热面温差对热导率的影响。试验表明:在测试温度下试样的热导率随中心量热器单位时间水流量的增加而增大,但当中心量热器单位时间水流量超过一定值后,热导率增大趋势变缓;确定水流量平板法测试的热导率与试样冷热面温差有关,可通过热导率与Δt/ΔT的拟合曲线计算曲线范围内或曲线外推温度下的热导率。

冷弯圆钢管截面材料特性分布模型研究

对取自10种不同截面尺寸、不同直径、不同厚度的冷弯圆形钢管的120个试件进行了材料性能试验研究。结果表明:冷弯效应对材料的强度和延性影响较大;含焊缝圆弧部位的屈服强度和极限强度均比不含焊缝圆弧的部位有较大提高,而伸长率明显降低,含焊缝圆弧的断面收缩率也略有降低;不含焊缝部位和含焊缝处的强屈比也略有不同,分别为1.24和1.16。基于试验研究结果,提出了冷弯圆形钢管截面的屈服强度、极限强度、强屈比、伸长率和断面收缩率沿截面的分布模型。当相应冷弯圆钢管截面的梁、柱强度和稳定分析中需要考虑冷弯效应的影响时,可以用此分布模型进行分析。

速练剂在棉针织物冷轧堆前处理中的应用

探讨速练剂KR-9组合在棉针织物冷轧堆前处理加工中的应用,针对棉针织物冷轧堆前处理加工进行相关产品的性能检测试验,研究棉针织物冷轧堆前处理加工配套助剂的相关技术指标要求。结果表明,在棉针织物冷轧堆加工中使用速练剂KR-9组合后直接水洗,其白度达到78.8%,瞬时毛效值为5.20cm,保证了前处理半成品的匀透效果,为提高成品的一次成功率提供了有力保障。

沥青路面冷再生试验路车辙变形的时空分布

为了揭示冷再生沥青混合料在结构中的力学行为,为道路维修养护中的结构设计提供依据,研究依托山东省某高速公路试验路的冷再生沥青路面结构及其中传感器监测数据,分析冷再生结构层在行车荷载作用下的动态响应特点及规律。依托实测温度场数据,构建黏弹性有限元仿真模型,分析了冷再生沥青路面结构车辙的分布规律。结果表明:对于试验路结构的冷再生沥青混合料层,行车速度与结构内部应变响应持续时间呈幂函数关系,在60~80 km/h的速度下,其结构层内部的力学响应频率接近10 Hz;在路面设计时,冷再生层可取其在20℃、10 Hz下的动态模量作为结构模量;对于冷再生沥青试验路结构,其一天中逐小时车辙量的分布主要与交通量相关,一年中的月车辙量的分布主要与温度相关,其中,一年之内的车辙累积主要发生在5—10月,冬季期内发生的车辙量几乎可以忽略不计;为避免由于结构层厚度增加导致过高的车辙预估量,需在计算沥青混合料层永久变形等效温度时对沥青层的厚度进行限制;此外,在高温条件下,相较于动态模量的改变,控制上、中面层沥青混合料在40~45℃左右的塑性变形发展速率对于减小路面永久变形的累积具有更为显著的作用。

基于正交试验的850吨冷剪机剪切失效机理分析及其优化设计

以减小850吨冷剪机剪切力为研究目的,从冷剪机剪切机理及特点出发,采用正交试验法分析剪切间隙、剪刃倾角、剪切速度、剪刃刀面宽度及剪刃重叠量等参数对剪切力的影响,分别以方差、极差及显著性作为影响因素的指标,并对其进行优先级排序,进而优化剪切参数,减小剪切力。优化剪切参数前后的冷剪机现场试验表明,优化前后冷剪机剪切力的实测值与仿真值误差均在5%以内,仿真结果可靠。采用优化后的剪切参数,冷剪机剪切相同规格钢筋时,上剪刃最大剪切力减小了5.84 kN,减小约13%,下剪刃最大剪切力减小了4.77 kN,减小约9.7%。经车间反馈,使用优化后的剪切参数可大幅延长冷剪机剪刃崩刃和磨损的周期,增长剪刃寿命和提高剪切效率。该研究对提高设备经济性和生产效率具有重要意义,可应用于同类型冷剪机的工程设计。

空腔部分填充的轻钢复合墙体耐火性能研究

为提升内填充轻钢复合墙体的抗火性能,开展了2块双层石膏板覆面岩棉内填充非承重轻钢复合墙体的抗火试验研究,探究了不同填充层布置对墙体抗火性能的影响。试验结果表明:相较于空腔全填充墙体,龙骨无填充墙体受火过程中热翼缘温升更慢、冷热翼缘温差更小;龙骨无填充墙体的承重抗火性能优于空腔全填充墙体的承重抗火性能。同时,在荷载比为0.27的条件下,相较于空腔全填充墙体,龙骨无填充墙体的耐火极限提升了11.5%左右,且龙骨无填充墙体的施工更为简便。因此,可考虑采用墙柱无填充的构造形式来代替内填充构造以提升该类墙体承重抗火性能。此外,所建立的轻钢复合墙体受火传热模拟方法适用于龙骨无填充、空腔全填充等不同构造形式的墙体,可为后续轻钢墙体抗火研究提供参考。

基于K2算法的发动机冷试贝叶斯网络模型研发

发动机冷试测试较传统热试方法可减少燃油消耗及排放,为提高冷试测试故障诊断精度,提出使用K2算法构建贝叶斯网络故障诊断模型。选取多台柴油机的相关冷试测试数据,分别构建基于专家知识和基于K2算法的贝叶斯网络故障诊断模型进行比较,结果表明,使用K2算法构建贝叶斯网络优于通过专家知识构建的贝叶斯网络,所提方案可以优化目前的故障诊断模型。