Numerical study of plasmas start-up by electron cyclotron waves in NCST spherical tokamak and CN-H1 stellarator

According to the physics of tokamak start-up,this study constructs a zero-dimensional(0D)model applicable to electron cyclotron(EC)wave assisted start-up in NCST spherical torus(spherical tokamak)and CN-H1 stellarators.Using the constructed 0D model,the results obtained in this study under the same conditions are compared and validated against reference results for pure hydrogen plasma start-up in tokamak.The results are in good agreement,especially regarding electron temperature,ion temperature and plasma current.In the presence of finite Ohmic electric field in the spherical tokamak,a study on the EC wave assisted start-up of the NCST plasma at frequency of 28 GHz is conducted.The impact of the vertical magnetic field B_(v)on EC wave assisted start-up,the relationship between EC wave injection power P_(inj),Ohmic electric field E,and initial hydrogen atom density n_(H0)are explored separately.It is found that under conditions of Ohmic electric field lower than ITER(~0.3 V m^(-1)),EC wave can expand the operational space to achieve better plasma parameters.Simulating the process of28 GHz EC wave start-up in the CN-H1 stellarator plasma,the plasma current in the zerodimensional model is replaced with the current in the poloidal coil of the stellarator.Plasma startup can be successfully achieved at injection powers in the hundreds of kilowatts range,resulting in electron densities on the order of 10^(17)-10^(18)m^(-3).

Cookie Baking Process Optimization and Quality Analysis Based on Food 3D Printing

In order to obtain better quality cookies, food 3D printing technology was employed to prepare cookies. The texture, color, deformation, moisture content, and temperature of the cookie as evaluation indicators, the influences of baking process parameters, such as baking time, surface heating temperature and bottom heating temperature, on the quality of the cookie were studied to optimize the baking process parameters. The results showed that the baking process parameters had obvious effects on the texture, color, deformation, moisture content, and temperature of the cookie. All of the roasting surface heating temperature, bottom heating temperature and baking time had positive influences on the hardness, crunchiness, crispiness, and the total color difference(ΔE) of the cookie. When the heating temperatures of the surfac and bottom increased, the diameter and thickness deformation rate of the cookie increased. However,with the extension of baking time, the diameter and thickness deformation rate of the cookie first increased and then decreased. With the surface heating temperature of 180 ℃, the bottom heating temperature of 150 ℃, and baking time of 15 min, the cookie was crisp and moderate with moderate deformation and uniform color. There was no burnt phenomenon with the desired quality. Research results provided a theoretical basis for cookie manufactory based on food 3D printing technology.

Effects of Pre-Strain on Bake Hardenability and Precipitation Behavior of Al-Mg-Si Automotive Body Sheets

The study investigates the effects of pre-strain on the bake hardenability and precipitation behavior of Al-Mg-Si automotive body sheets. The scanning electron microscopy, transmission electron microscopy, tensile test, Vickers hardness test, and differential scanning calorimetry were conducted for the purpose. It was found that the pre-strain treatment partially inhibits the natural aging hardening effect but cannot completely eliminate it. The pre-straining significantly enhances the bake hardening effect, with the 5% pre-strain sample showing the highest increase in yield strength and hardness. The formation of fine β" precipitates and dislocation structures contribute to the observed strengthening. Additionally, the study highlights the importance of optimizing pre-strain levels to achieve the best balance between strength and ductility in bake-hardened aluminum alloys.

Experimental Procedure and Hardening Model to Consider Forming and Baking Effects in Simulation

This paper investigated an experimental method for bake hardening properties, a technique for deriving the true stress-strain curves after reaching the maximum load, and a constitutive equation considering both work hardening and bake hardening in order to apply the work hardening occurring in the forming process of parts and the bake hardening induced in the baking process to an automotive crash simulation. A general bake hardening test is that a pre-tensioned specimen is baked and then the same specimen is tensioned again without any further treatment. For a bake hardening test of automotive steel with a tensile strength of 1.2 GPa or more, fractures often occur in curvature section outside, an extensometer due to the difference in the material strength caused by non-uniform bake hardening. This causes a problem in that the bake hardening properties cannot be obtained. In this paper, to prevent curvature fracture, tensile specimens were re-machined in the uniformly deformed region of large specimens subjected to pre-strain, and the re-machined specimens with uniform strength in all regions were re-tensioned. In the bake hardening test of ultra-high strength steels with a tensile strength of 1 GPa or more, shear band fractures occur when the pre-strain is large. This makes it impossible to obtain a true stress-strain curve because there is no uniformly deformed region under a tensile test. To overcome this problem, a new method to calculate the true stress-strain curve by comparing experimental results and the load calculated by the local strain obtained from digital images was developed. This method can be applied not only where shear band deformation occurs, but also in necking deformation, and true stress-strain curves for strains up to 2 - 3 times the uniform elongation can be obtained. A new constitutive equation was developed since an appropriate hardening model is required to simultaneously apply the work hardening and the bake hardening to the simulation. For the newly developed model, the user material subroutine of LS-Dyna was configured, and the simulation was performed on the single hat specimens with pre-strain. When both work hardening and bake hardening were considered, there was a significant increase in absorbed energy compared to when only work hardening was considered. This means that both work hardening and bake hardening should be considered in the car crash simulations to enhance the accuracy of the simulation.

Effects of pre-strain and baking parameters on the microstructure and bake-hardening behavior of dual-phase steel

In a typical process, C-Mn steel was annealed at 800℃ for 180 s, and then cooled rapidly to obtain the ferrite-martensite microstructure. After pre-straining, the specimens were baked and the corresponding bake-hardening （BH） values were determined as a function of pre-strain, baking temperature, and baking time. The influences ofpre-strain, baking temperature and baking time on the microstructure evolution and bake-hardening behavior of the dual-phase steel were investigated systematically. It was found that the BH value apparently increased with an increase in pre-strain in the range from 0 to 1%; however, increasing pre-strain from 1% to 8% led to a decrease in the BH value. Furthermore, an increase in baking temperature favored a gradual improvement in the BH value because of the formation of Cottrell atmosphere and the precipitation of carbides in both the ferrite and martensite phases. The BH value reached a maximum of 110 MPa at a baking temperature of 300℃. Moreover, the BH value enhanced significantly with increasing baking time from 10 to 100 min.

Physicochemical Properties, Baking Performance and Sensory Evaluation of Bakery Shortening Enriched with Diacylglycerol

The purpose of this study was to investigate the suitability of palm diacylglycerol （PDAG）-enriched formulations for bakery shortening. Three types of palm diacylglycerol olein （PDAGOL） at different degree of unsaturation （PDAGOL1V56, PDAGOLIV62 and PDAGOLIV64） were used as main raw materials blended with palm stearin （PS）. The blending compositions ranged from 30% to 70% of PDAGOLIV56/PS, PDAGOLIV62/PS and PDAGOLIV64/PS, respectively. The physicochemical properties of all binary blend systems were characterized for fatty acid composition （FAC）, slip melting point （SMP） and solid fat content （SFC）. The selected bakery shortening formulations were further characterised for polymorphic form of fat crystal and thermal behavior, using X-ray diffractometer （XRD） and differential scanning calorimetry （DSC）. Bakery shortening enriched with diacylglycerol that were produced from 40DS56 （40% PDAGOLIV56/60% PS）, 40DS62 （40% PDAGOL1V62/60% PS） and 40DS64 （40% PDAGOLIV64/60% PS） had 45%-50% unsaturated fatty acid and crystallized in β ＋ β polymorphs; thus they were suitable for shortening system. Based on product＇s baking performance, it could be found that all Madeira cakes prepared from bakery shortening enriched with diacylglycerol had higher specific cake volume as compared to commercial shortening （CS）. In customer acceptance test, Madeira cake made from 40DS56 shortening scored the highest rating for all sensory attributes, including overall customer acceptability. It had given an indication that 40DS56 shortening formulation was the most suitable fat blends to be used as bakery shortening.

Numerical Simulation of a Two-Phase Flow with Low Permeability anda Start-Up Pressure Gradient

A new numerical model for low-permeability reservoirs is developed.The model incorporates the nonlinear characteristics of oil-water two-phase flows while taking into account the initiation pressure gradient.Related numerical solutions are obtained using a finite difference method.The correctness of the method is demonstrated using a two-dimensional inhomogeneous low permeability example.Then,the differences in the cumulative oil and water production are investigated for different starting water saturations.It is shown that when the initial water saturation grows,the water content of the block continues to rise and the cumulative oil production gradually decreases.

Dynamic evaluation of a scaled-down heat pipe-cooled system during start-up/shut-down processes using a hardware-in-the-loop test approach

Micro-mobile heat pipe-cooled nuclear power plants are promising candidates for distributed energy resource power genera-tors and can be flexibly deployed in remote places to meet increasing electric power demands.However,previous steady-state simulations and experiments have deviated significantly from actual micronuclear system operations.Hence,a transient analysis is required for performance optimization and safety assessment.In this study,a hardware-in-the-loop(HIL)approach was used to investigate the dynamic behavior of scaled-down heat pipe-cooled systems.The real-time features of the HIL architecture were interpreted and validated,and an optimal time step of 500 ms was selected for the thermal transient.The power transient was modeled using point kinetic equations,and a scaled-down thermal prototype was set up to avoid mod-eling unpredictable heat transfer behaviors and feeding temperature samples into the main program running on a desktop PC.A series of dynamic test results showed significant power and temperature oscillations during the transient process,owing to the inconsistency of the rapid nuclear reaction rate and large thermal inertia.The proposed HIL approach is stable and effective for further studying of the dynamic characteristics and control optimization of solid-state small nuclear-powered systems at an early prototyping stage.

Preparation of coated sand for selective laser sintering and optimization of baking process of sand moulds

A cold method was used to prepare coated sand for application in the selective laser sintering(SLS)process.Tensile strength,loss on ignition,gas evolution,and accuracy of the SLS samples were tested and analyzed,and the baking process was thoroughly investigated.Compared with coated sand prepared by the hot method,the cold method yields a more uniform and complete resin film on the sand's surface,resulting in enhanced tensile strength and accuracy.Additionally,the cold method requires a lower binder content to meet the same strength requirements,thereby minimizing gas evolution,reducing porosity defects,and ultimately improving casting quality.The coated sand samples prepared through the cold method exhibit superior accuracy,with a size error of within±0.4 mm.In contrast,the coated sand samples prepared by the hot method display a lower accuracy,with an average negative error of 2.1993 mm.The highest tensile strength could be attained by controlling the baking temperature within a suitable range(180-190°C),which can effectively reduce the generation of gas,thus contributing to improved overall performance.

Natural and modified food hydrocolloids as gluten replacement in baked foods:Functional benefits

Gluten,the protein responsible for the superior viscoelastic properties of refined wheat flour dough over glutenfree cereals,causes celiac disease in people susceptible to gluten-allergy.Moreover,the sustainability of using wheat flour in baked foods is threatened by its high cost,especially in countries that depend on imported wheat for their bakery industry.Research has shown that hydrocolloids serve as gluten replacements in baked foods,in response to these challenges.Food hydrocolloids are a class of high-molecular weight polysaccharides and proteins,which serve as functional ingredients in the food industry that modify the foods’rheological and textural properties.They function as stabilizers,viscosity modifiers,gelling agents,water binders,fibres,and inhibitors of ice crystal in foods.Further,food hydrocolloids have also been reported to possess health-promoting properties,such as lowering of postprandial blood glucose and plasma cholesterol concentrations,colon cancer prevention,and modulation of intestinal transit and satiety.They are obtained from plants,animals or microorganisms,and can be used in their natural or modified forms.The aim of this paper is to review the functional benefits of natural and modified hydrocolloids as gluten replacements in baked foods,emphasizing their physicochemical,nutraceutical,and sensorial importance.The application effects of food hydrocolloids as gluten substitutes in gluten-free baked products’quality were discussed.Also,some practical approaches to improve the quality of gluten-free baked products,in response to an increasing consumers’demand and the rising cost of refined wheat flour were highlighted.

炙黄芪-水蛭联合阿加曲班注射液治疗气虚血瘀型急性脑梗死的疗效观察

[目的]探究炙黄芪-水蛭联合阿加曲班注射液治疗气虚血瘀型急性脑梗死的疗效观察。[方法]选取2021年2月—2023年2月于本院进行急性脑梗死治疗的患者110例,按照随机数字表法将其分为阿加曲班注射液组(西药组)34例、炙黄芪-水蛭组(中药组)36例,以及联合组40例。西药组给予阿加曲班注射液;中药组给予炙黄芪-水蛭;联合组给予炙黄芪-水蛭联合阿加曲班注射液治疗。评估患者治疗前后中医证候积分水平;采用美国国立卫生研究院卒中量表(NIHSS)、改良Rankin(mRS)评分量表评估患者自身的神经功能缺损情况以及神经功能恢复情况;检测脑血流阻力指数(RI)、舒张期血流速度(Vd)、收缩期峰值流速(Vs)、平均血流速度(Vm)、血管内皮生长因子(VEGF)、一氧化氮(NO)水平。[结果]治疗后,联合组中医证候积分、NIHSS、mRS评分、RI、VEGF水平均低于西药组、中药组(P<0.05);Vd、Vs、Vm、NO水平高于西药组、中药组(P<0.05);联合组总有效率较高(P<0.01)。[结论]经炙黄芪-水蛭、阿加曲班注射液联合治疗,其气虚血瘀型急性脑梗死患者中医证候积分水平降低,相关神经功能、血流情况及血管内皮损伤情况均得到显著改善,临床治疗效果显著。

Box-Behnken响应面法优化焙烤食品复配防腐剂的研究

本研究以纳他霉素、乳酸链球菌素、ε-聚赖氨酸和茄非可食部分生物碱提取液为主要原料,在单因素试验的基础上,采用Box-Behnken响应面法优化确定焙烤食品复配防腐剂最佳配比,并进行验证试验。结果表明,在纳他霉素浓度为0.078 g·kg^(-1)、乳酸链球菌素浓度为0.080 g·kg^(-1)、ε-聚赖氨酸浓度为0.060 g·kg^(-1)、茄非可食部分生物碱提取液浓度为14%时,复配防腐剂的抑菌效果最佳。验证试验分别测定对照组和试验组的菌落总数和霉菌数,对照组的菌落总数、霉菌数明显多于试验组,且试验组未检出霉菌。

DP900钢的成形性及预应变对烘烤硬化行为的影响

对汽车结构件用DP900钢的成形极限图进行了测试和研究,并运用数学模型进行了预测分析。利用内耗仪和透射电子显微镜从微观角度研究了预应变对烘烤硬化值的影响。结果表明:DP900钢室温下的力学性能为屈服强度604 MPa,抗拉强度935 MPa,均匀伸长率达到14%,断后伸长率为19%。冲压成形过程中,成形极限FLD0为0.245,基于Hollomon方程建立的成形极限数学模型的预测误差在0.2%~13.5%,平均误差为5.87%。预应变量的大小对BH值有显著的影响。随预应变增大,BH值先升高后降低,预应变为7%时达到最高值45 MPa。内耗峰值变化趋势与BH值一致。

EACHTCS智能变频除湿热泵烤房研究与应用

针对使用燃煤烤房污染大、成本高等问题,研究应用一种以变频热泵为热源的智能变频除湿热泵烤房,以常规电热泵供热烤房和燃煤密集烤房为对照,对比分析该型烤房在烘烤能耗、烟叶质量等方面的差异。结果表明:与传统燃煤型密集烤房相比,EACHTCS智能变频除湿热泵烤房能耗成本可降低40.8%;与普通热泵烤房相比,节能效果可达14.9%。烤后烟叶结构疏松,香气量足,油分增多,上等烟比例可提高3%~5%(绝对值)。综合分析,该型烤房可为优化当前密集烤房供热方式、改善烘烤性能、推动烟叶烘烤降本增效提供借鉴。

HPLC多波长切换指纹图谱结合化学计量学研究白术土炒前后成分变化规律

目的 建立测定白术、土白术水溶性和脂溶性成分的高效液相色谱-二极管阵列检测器(HPLC-DAD)多波长切换指纹图谱,结合化学计量学研究白术土炒前后成分变化规律。方法 建立白术、土白术水溶性及脂溶性成分的HPLC-DAD多波长切换指纹图谱测定方法,测定17批白术和17批土白术的HPLC指纹图谱,采用相似度评价、聚类分析、OPLS-DA分析进行统计分析。结果 白术指纹图谱中共标定9个共有峰,土白术指纹图谱中共标定10个共有峰。指认了新绿原酸、绿原酸、白术内酯Ⅰ、白术内酯Ⅱ、白术内酯Ⅲ及苍术酮6个成分,土炒后1号峰、4号峰(白术内酯Ⅲ)、8号峰(白术内酯Ⅱ)峰面积增加,2号峰(新绿原酸)、3号峰(绿原酸)、5号峰、6号峰、7号峰、9号峰(白术内酯Ⅰ)、10号峰(苍术酮)土炒后峰面积均降低。结论 所建立指纹图谱方法能够系统地分析白术土炒前后化学成分的变化规律,可为进一步规范白术土炒工艺,制定土白术专属性质量标准,研究土白术炮制原理提供实验基础。

基于指纹图谱和化学计量学的生姜及其炮制品的质量评价

目的建立生姜及其炮制品指纹图谱及多成分含量测定方法,评价生姜及其炮制品的质量。方法采用高效液相色谱(HPLC)法建立生姜及其炮制品(干姜、炮姜、姜炭)的指纹图谱,同时测定其5个成分的含量,并采用相似度评价和化学模式识别对数据进行分析。结果建立了生姜及其炮制品的指纹图谱,相似度为0.931~0.996,标定15个共有峰,对比标准品,指认出5个成分(6-姜酚、8-姜酚、10-姜酚、6-姜烯酚、姜酮)。HPLC测定生姜及其炮制品(干姜、炮姜、姜炭)中6-姜酚、8-姜酚、10-姜酚含量均符合2020版《中国药典》标准,鲜品生姜中6-姜烯酚、姜酮含量极低,经炮制为干姜、炮姜后其含量显著升高。聚类分析可将生姜及炮制品各分为一类;正交偏最小二乘判别分析筛选出5个变量重要性投影(VIP)值大于1的成分。结论该研究建立的HPLC指纹图谱及含量测定方法专属性强、简便可行、稳定可靠,结合化学识别模式方法,可为生姜及其炮制品的质量评价提供参考。

钼碚砂氨浸过程中钾的释放行为与控制研究

低钾钼产品在电子、医疗等领域具有广泛的应用前景,而氨浸对低钾钼产品的生产具有十分重要的影响。为了更好地控制氨浸过程中钾的释放量以减少后续工艺中的降钾压力,通过对钼焙砂氨浸过程中的释钾影响因素进行了单因素模拟实验,分析了钾元素的释放规律,并给出了其动力学模型和控制方法。结果表明,温度、固液比、钼焙砂粒度等对钾元素的释放具有较大的影响,最佳的氨浸条件为:温度30℃、固液比1∶3,钼焙砂粒径范围150~178μm,氨水浓度20%。此外,Ca元素更利于氨浸过程除钾,而Na元素不利于氨浸过程除钾。熟石灰对水洗除钾有一定作用,碳酸钠对水洗除钾的效果并不明显,故在钼焙砂水洗过程中加入熟石灰有利于低钾钼酸铵的生产。钼焙砂氨浸过程前期释钾速度较快,后期速度变慢,得到Avrami方程可以较好地模拟氨浸前期和后期的释钾过程,确定了氨浸过程的动力学方程。

不同季节烘青绿茶中的挥发性成分与关键香气活性成分分析

为确定不同采收季节烘青绿茶香气成分的差异,采用搅拌棒吸附萃取法结合气相色谱-质谱联用技术系统研究3个浙江主推茶树品种制备的春、秋季烘青绿茶中的挥发性成分的组成和含量,采用多元统计分析和香气活性值(odor activity value,OAV)测定法分析春、秋季烘青绿茶中的关键差异性挥发性化合物和关键香气活性成分。结果表明,在春、秋季烘青绿茶中共鉴定出105种挥发性成分,其中以醇类、酯类和酮类化合物数量最多,可占总挥发性成分的50%以上。通过主成分分析、偏最小二乘判别分析和显著性分析等,显示植醇、1-辛醇和1-辛烯-3-醇等38种化合物在春、秋季烘青绿茶中存在统计学差异(P<0.05)。结合定量和OAV分析,最终鉴定植醇、己醛、壬醛、1-辛烯-3-醇、辛醛和反式-β-紫罗兰酮6种化合物为烘青绿茶中的关键香气活性成分(OAV>1),其中,植醇在秋季样品中质量浓度(967.65 ng/mL)极显著高于春季(370.82 ng/mL),推测可能与秋季鲜叶原料中具有更充足的叶绿素前体储备有关;而己醛等其他成分则主要表现为在春季含量更高,可能与调控脂肪酸或类胡萝卜素衍生物形成的酶活性存在季节性变化有关。

彰显龙岩CB-1烟叶清甜蜜甜香型风格密集烘烤工艺研究

研究龙岩地区‘翠碧一号’的密集烘烤工艺,为彰显其清甜蜜甜香型风格提供参考。为彰显‘翠碧一号’烟叶清甜蜜甜香型风格,以福建龙岩烟区栽种‘翠碧一号’下、中、上部的适熟烟叶为实验材料,设置3种烘烤工艺,采用“背靠背”编烟方式编竿装烟,对烤后烟叶分别按下、中、上部进行分级,然后进行鉴定,统计外观、化学成分及感官质量等信息。结果显示,‘翠碧一号’(CB-1)品种烟叶下部烟宜采用T3(高温/高低高湿)烘烤工艺,关键烘烤阶段干/湿球温度为:变黄期38~40/37~38℃、凋萎期42/36℃、变筋期46/36℃、干片期50~54/38~39℃、干筋期60~65/40~42℃,中、上部烟叶宜采用T1(高温/高湿)烘烤工艺,关键烘烤阶段干/湿球温度为:变黄期38~40/37~38℃、凋萎期42/38℃、变筋期46/38℃、干片期50~54/39~40℃、干筋期60~65/40~42℃。该研究为彰显‘翠碧一号’香型的密集烘烤工艺提供技术参考。

500 kA铝电解槽焙烧工艺控制和优化

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