微波干燥过程中的土豆组织温度变化及水分迁移特性

为探索淀粉类果蔬多孔介质在微波干燥过程中的热质传递特性,以土豆为研究对象,测量其不同功率下微波干燥过程中土豆组织的温度和质量以及水分状态变化。结果表明,微波干燥过程中土豆组织的温度可以分为快速升温、恒温及降温段3个阶段,土豆质量减少主要发生在恒温段,且该阶段物料的失重率占总失重率的90%以上。微波干燥过程中自由水短暂升高至93.21%后逐渐降低至15.61%,而不易流动水和结合水均先降低后升高。淀粉对于微波干燥中的水分迁移有重要影响,淀粉失去薄膜水后固化,使得土豆片的骨架硬度增加,从而增大水分迁移阻力。     

微波膨化技术在食品中的应用研究

膨化技术作为一种新型食品生产技术,正逐步在食品工业中得到广泛的应用。微波膨化是利用微波的加热特性,使物料产生蒸气压梯度,当物料压力大于它所承受能力时瞬间出现膨化现象。由于微波的低温高效作用,使食品能较好地保留其营养成分,保持食品原有的色、香、味,保证食品的品质。介绍了微波技术的机理及应用,着重讨论了微波膨化技术的作用机理、特点及在食品中的应用,详细论述了影响淀粉微波膨化效果的主要因素。     

新疆石河子冻土特征及冻土融化期地温、冻土深度预报研究

为了确保春季播种安全,有必要开展播种期地温的监测和冻土融化深度预报业务。利用新疆农八师冻土气象观测资料,运用相关系数和线性回归方法,分析冻土特征及融化过程中地温变化、深度变化规律,建立春季冻土融化预报模型。结果表明,新疆农八师垦区稳定冻土期在11月中旬至翌年3月下旬,冻土最大深度呈逐年变浅趋势,倾向率为-5.4 cm/10 a;冻土结冻日期推后,倾向率为2.0 d/10 a;冻土化通日期提前,倾向率为-1.5 d/10 a。冻土融化期在3月中旬至4月上旬,冻土融化速率在3.1~4.0 cm/d之间。春季地温与平均气温、冻土融化深度与正积温具有显著的正相关,以此建立了相应的预报模型。10 cm地温预报模型历史回代准确率在96%以上,冻土融化深度预报模型历史回代准确率在94%以上。通过模型可以开展春季地温和土壤融化预报业务。     

季节性冻融期不同地下水位埋深下土壤温度变化特征

土壤温度是土壤热状况的综合表征指标,影响土壤养分分布和冬春季节作物生长发育。以山西省水文水资源勘测局太谷均衡实验站为试验基地,对冻融期4种不同地下水位埋深下的土壤温度进行了分析研究。结果表明：在地下水浅埋区,冻融期地温的变化滞后气温变化,且滞后时间随土壤深度的增加而增大。12月初-2月下旬,地下水位为1．0m埋深的土壤温度较高;消融期地下水位为1．5m埋深下的土壤温度迅速回升。而0．5m埋深下的土壤温度较低且回升较慢;同一地下水埋深下,随着土壤深度的增加。剖面温度增高。50cm深度之下的土壤温度受地下水位埋深的影响较弱。研究成果可为冬春作物播种、预防冻害提供参考依据。     

魔芋茎尖玻璃化冻存研究

研究了魔芋茎尖玻璃化冻存的主要技术环节，建立了较适宜的魔芋种质资源超低温保存体系：在实体显微镜下，从继代培养2周的不定芽上切取1～1.33mm大小的茎尖，经0.7mol/L蔗糖的MS-NH+4培养液室内预培养2d，玻璃化溶液PVS2室温下处理10～20min，直接投入液氮中保存。保存后，茎尖经40～77℃水浴快速化冻，1.2mol/L蔗糖的培养液     

Stress Corrosion of Concrete Exposed to the Action of Freezing-thawing Cycles

Through the method of accelerated freezing-thawing and room-temperature corrosion, the stress corrosion of three kinds of concretes subjected to 5.0%MgSO4(in mass)solution was studied. The considered concretes include High Strength Concrete(HSC), High-Volume Mineral Admixture Concrete(HVMAC) and High Durable Concrete(HDC) added with high-volume mineral admixture, air-entraining agent, superplasticizer, fibers and expansion agent. The results showed that the relative dynamic elastic modulus of concrete went through strengthen and deterioration stages subjected to stress corrosion, whether the room temperature or freezing and thawing conditions. The length of time of these two stages are closely related with the experimental temperature. Freezing and thawing action significantly accelerated the process of sulphate stress corrosion damage. Under the action of freezing and thawing, stress corrosion strengthening the period length of HSC shorter 96%, deterioration section of the length of time shorter 88%, compared with the length of time at the corresponding room temperature. Deterioration section of the length of time of HVMAC is reduced by 98%, while the HDC reduced by 71%. The effect of freezing and thawing, HDC freezing-thawing cycles when the stress corrosion damage occurred were longer 1.5 times and 13 times than the HSC and HVMAC. Thus in the cold regions, HDC showed more resistance to sulfate stress corrosion.     

Measure and Analysis on the Temperature Field of Sodium Silicate Bonded Sand Heating by Microwave Energy

The temperature field of sodium silicate bonded sand heating by microwave energy is measured and analyzed by the related characteristic quentities. The result shows that sodium silicate bonded sand heating by microwave energy has characters such as temperature rising speedy and heating occurring from inside to outside at the same time. The reasons of those characters are discussed by testing and analyzing. The viewpoint that the temperature rising of sodium silicate bonded sand heating by microwave energy is revocable by sodium silicate absorbing microwave energy is proposed. The results of this study are useful on rightly understanding the essentials of the heating by microwave energy for sodium silicate sand and rightly constituting heating technology.     

提高西门塔尔牛冷冻精液使用效果的研究

为提高西门塔尔牛冷冻精液的使用效果,从筛选稀释液配方、选择最佳解冻温度与解冻后保存温度三个方面进行了研究。实验结果表明：（1）通过比较三种冷冻精液保存稀释液对冷冻后精子活力的影响,表明稀释液Ⅲ和稀释液Ⅱ的保存效果均极显著优于稀释液Ⅰ的保存效果（P<0.01）,稀释液Ⅲ与稀释液Ⅱ间的保存效果差异不显著（P>0.05）（2）将牛细管冻精在不同温度、不同时间下进行解冻,解冻后精子活率随解冻温度升高（40℃~65℃）而升高,但高温下（80℃）解冻精子活率低于解冻温度为（40℃~65℃）（3）在两个温度范围进行精液解冻后保存试验,结果以（0℃~5℃）范围解冻后保存效果较好。     

绿茶多酚微波辅助提取和纯化工艺研究

摘要：以碎绿茶为原料,采用二步法提取和纯化茶多酚,通过及正交试验确定较佳工艺为：第一步采用微波乙醇溶液提取效果最好,最佳条件是乙醇溶液浓度为50%,料液比为l:30,浸提20min后,用320W微波辐射25s,再常温浸提60min,重复浸提2次,在此工艺条件下茶多酚浸出率为21.74%。第二步采用离子沉淀法纯化茶多酚,最佳工艺条件为选用A13++Zn2+复合沉淀剂,沉淀剂加入量与茶叶质量之比为3:20,沉淀温度在25℃左右,当茶多酚沉淀完全后迅速分离,最终得到的茶多酚浓缩液纯度可达99.50%。     

Study on the Technology and Engineering Application Method of Sodium Silicate Bonded Sand Cured by Microwave Energy

The Influences of modulus and dosage of sodium silicate and microwave energy heat up technology for instant strength and retained strength are measured and analyzed by the numbers. The results show that instant strength is reduced when the time of microwave energy heat up is too long. The engineering application design is recommended.     

微波消解——凯式定氮法在大豆蛋白质含量测定中的应用

介绍微波消解-凯式定氮法测定大豆中蛋白质含量的方法,采用密闭微波消解样品,优化微波消解条件。方法的相对标准偏差为1.75%,回收率在99.2%~102.2%之间。分析结构与国标对照无显著性差异。该法具有消化时间短、环境污染小等特点,为快速测定大豆蛋白含量以及改善操作人员工作环境,提供了参考。     

不同保鲜方法对美味牛肝菌贮藏品质的影响

采用低温、气调和微波三种保鲜方法对美味牛肝菌进行贮藏保鲜试验研究,结果表明,适当的低温、气调和微波处理,均可有效延长新鲜美味牛肝菌的保鲜期,降低腐烂率和失重率。其中,以2℃低温,5%O2+5%CO2的气调环境结合削除美味牛肝菌柄脚后微波处理5 s的处理方法保鲜效果最好。     

Microwave Sintering of Magnetite Concentrates

A basic research about microwave sintering of three kinds of concentrate has been investigated.Three parameters are included: microwave heating time,carbon addition in sample,variable basicity(CaO/SiO_2).As the microwave heating time increased,the temperature of magnetite concentrates increased too,once the temperature reached a point,the temperature change slowed down.With the same microwave heating condition,to add carbon powder will decrease the heating temperature of sample.In the condition of that the basicity is 2.5,the heating time is 20 min,and the microwave output power is 1 000 W,the sinter product with hole can be got,but the density is lower compared with the regular sinter product,and the reason needs a further research.     

台湾青枣贮藏期间外形与生理变化

台湾青枣在贮藏期间失水严重,硬度迅速下降;呼吸速率缓慢上升,跃变高峰出现在第6天;果皮叶绿素和蛋白质含量一直呈下降趋势,而维生素C和有机酸的含量先升后降,室温贮藏6天后其商业品质迅速下降.     

Influences on Engineering Properties of AS Firming Agent Modified Soil by Freeze-thaw Cycles

To study the freeze-thaw durability of Aught-Set(AS) firming agent modified soil, a series of triaxial tests were conducted. The mutual relationships between stress-strain relationship, static strength, dynamic modulus and critical dynamic stress of AS firming agent modified soil and curing time, freeze-thaw cycles, cooling temperature were deeply analyzed. The results show that the unconfined compressive strength of 7 d is 75% than that of 28 d. The stress-strain curves of AS firming-agent modified soil are strain-softening and in brittle failure shape. The static strength, critical dynamic stress and resilient modulus decrease in exponential form with the increase of freeze-thaw cycles, and after 6 cycles of freezing and thawing, the trend is stable. Under the same dynamic stress, the cumulative plastic strain of samples develop from stable state to failure because of freezing and thawing. After many times of freeze-thaw cycles, the lower the negative temperature, the little influence on the mechanic properties.     

Characteristics of combustion and NOx emission in lowconcentration coal bed methane boiler retrofitted from coal fired boiler

Coal fired chain grate boiler is retrofitted to coal bed methane boiler. The flow, combustion and NOx emission characteristics of low concentrations methane in the boiler furnace are studied by the numerical simulation and experiments. The results show that the axial velocity reaches the maximum at 0.5 m from the nozzle and declines sharply in the range of -0.4~0.4 m on the width direction. With the heat load increases, the position of highest temperature moves to the rear of furnace and the simulation and experimental results agree well. At the front of the furnace, the obvious bimodal distribution of temperature at low heat load along the width direction is found, but it is a single peak distribution at 100% heat load. At the rear of the furnace, the temperature shows bimodal distribution at all kinds of heat loads. Gas temperature at boiler furnace outlet increases linearly with the increasing of heat load but the experimental results are slightly lower than the simulated results. The NOx is mainly produced in the middle and rear of furnace with high temperature, and the position of NOx peak lags far behind that of temperature peak. With the excess air coefficient increases, the highest furnace temperature and NOx generation increases and then decreases.     

微波预处理超声辅助酶解大豆秸秆条件优化

为提高油料作物秸秆酶解效率,对大豆秸秆进行微波预处理,然后进行超声辅助酶解。经扫描电镜分析,大豆秸秆的致密结构经微波预处理后,得以明显破坏,可以更利于为纤维素酶水解。采用正交实验对微波预处理条件进行优化,结果表明微波预处理大豆秸秆最优条件为：微波辐射功率400W,辐射时间40min,辐射温度60℃。经微波预处理、超声辅助酶解条件优化后,水解7 h 酶解率达到11.06%,与常规条件酶解48 h 的酶解率（11.77%）基本相当,酶解效率显著增加。     

温度对草莓加工过程中VC含量的影响

采用蒸汽、微波加热的方法,研究不同热处理对草莓VC含量的影响,以确定草莓热烫处理方式与工艺参数.结果表明,微波加热时间控制在80 s以内,草莓还原型VC保存率在90%以上,明显高于蒸汽处理,可达到较好的软化效果,同时还具有加热均匀、升温迅速的特点.     

VC对微波降解蓝莓提取物矢车菊素-3-葡萄糖苷的影响

将不同浓度（0.8、0.4、0.2 mg/L）蓝莓提取物矢车菊素-3-葡萄糖苷分别与0.8 g/L的VC混合,在70℃、400 W、1 000 r/min条件下微波处理10 min,以不加VC为对照,采用pH示差法测定各处理中矢车菊素-3-葡萄糖苷的含量,并研究不同微波功率、温度以及时间下VC对矢车菊素-3-葡萄糖苷的保护作用。结果表明,矢车菊素-3-葡萄糖苷降解率随着微波温度、功率以及时间的增加而增加,VC对不同处理条件下的微波降解矢车菊素-3-葡萄糖苷均有一定的保护作用,保护率在5%~10%。该结果可为微波加热食品中活性组分的保护提供一定的理论依据。     

微波预处理制备黑蒜工艺优化及品质比较

以独蒜为原料,研究微波预处理优化黑蒜加工工艺和对黑蒜品质的影响。以微波预处理功率、微波预处理时间以及黑蒜制备处理时间为因素,采用正交试验进行工艺优化,并分析黑蒜的品质。结果表明,微波预处理黑蒜优化的工艺条件为:投放6个大蒜,微波处理功率490 W,微波处理时间12 s,黑蒜制备时间10 d时(其中前120 h温度为80℃,后期温度为70℃),相对湿度60%~80%之间,制备的黑蒜中总酚含量为(7.71±0.06) mg/g。在该条件下制备的黑蒜与不经微波预处理的黑蒜相比,总酚、还原糖及总酸含量有极显著提高,蒜氨酸变化不显著,感官评分较高。因此,微波可以用于黑蒜制备的预处理。