Effect of harvest time on the chemical composition and antioxidant capacity of Gannan navel orange(Citrus sinensis L. Osbeck 'Newhall')juice

The present study investigates the chemical composition and antioxidant capacity of juice from the Gannan navel orange, which is harvested at one-to two-week intervals during the ripening period. The total soluble solid(TSS), total polyphenol content(TPC), total flavonoid content(TFC), sucrose and hesperidin contents gradually increase with the ripening of the fruit, followed by slight declines at the late maturity stage. Contrary to these observations, the contents of titratable acid(TA), vitamin C(Vc), and limonin trend downward throughout the ripening period. However, the contents of fructose, glucose, and narirutin fluctuate throughout the harvest time. Three in vitro antioxidant assays consistently indicate that the harvest time exerts no significant influence(P>0.01) on the antioxidant capacity. Furthermore, principal component analysis(PCA) and Pearson’s correlation test are performed to provide an overview of the complete dataset.This study provides valuable information for evaluating the fruit quality and determining when to harvest the fruit in order to meet the preferences of consumers. Meanwhile, our observations suggest that the fruits subjected to juice processing should be harvested at the late maturity stage to alleviate the "delayed bitterness" problem without compromising the antioxidant capacity and the flavonoid content in the juice.

Harvest Time and Fertility Effects on Yield and Quality of Forage from Alfalfa, Hybrid Bromegrass and Their Mixture

A field experiment with 24 treatments consisting of three perennial forage crops [alfalfa (Medicago sativa L. cv. AC Longview), hybrid bromegrass (Bromus riparius Rehm & Bromus inermis Leyss. cv. AC Success) and their mixture], four Cut 1 dates (approximately June 20, July 10, July 30 or August 20), and two fertilizer levels (unfertilized and fertilized) was established in late May 2014, on a Black Chernozem [Udic Boroll] silty clay soil. Forage dry matter yield [DMY], and concentration (g·kg−1 DM) of crude protein [CP], total digestible nutrients [TDN] and acid detergent fiber [ADF] data were collected over 3 years from 2015 to 2017. The fertilizer treatments were imposed in 2016 and 2017. Forage crops were initially cut at four Cut 1 dates, and again cut [Cut 2] in autumn (September 2 in 2015, November 7 in 2016 and October 5 in 2017). For all three forage crops, forage DMY usually increased when Cut 1 was delayed. Delaying Cut 1 reduced forage DMY for Cut 2. Total DMY (Cut 1 + Cut 2) for all three forage crops was highest from the combination of July 10 and late Autumn cuts. Alfalfa-bromegrass mixture produced higher DMY than bromegrass or alfalfa alone. Fertilizer application resulted in a significant increase in Cut 1 and total DMY for bromegrass. The CP concentration in Cut 1 forage usually declined as the forage crops matured. The CP concentration was highest for alfalfa, followed by alfalfa-bromegrass mixture, and much lower for bromegrass. There was little or no effect of forage crop maturity on the TDN and ADF concentrations in forage. The TDN concentration was higher and ADF concentration was lower in forage from alfalfa or alfalfa-bromegrass mixture than bromegrass. Fertilizer application significantly increased CP concentration for alfalfa-bromegrass mixture. Delaying harvesting for Cut 1 increased ADF yield and TDN yield until Late July, but CP yield generally decreased with crop maturity. The ADF yield and TDN yield were higher for alfalfa-bromegrass mixture than bromegrass or alfalfa alone, and CP yield was similar for alfalfa and alfalfa-bromegrass mixture but considerably higher than bromegrass. Fertilizer application increased CP yield and ADF yield for bromegrass and alfalfa-bromegrass mixture, and TDN yield only for bromegrass. In conclusion, total DMY (Cut 1 + Cut 2) was highest for a combination of Early July and Autumn cuts. Forage yield was highest for alfalfa-bromegrass mixture, followed by alfalfa and lowest for bromegrass. The CP and TDN concentrations were higher, and ADF concentrations were lower in forage from alfalfa or alfalfa-bromegrass mixture than bromegrass.

Comparison of Agrimophol Content in Agrimonia pilosa Ledeb. from Luzhou at Different Harvest Time

[ Objectives] This study was conducted to compare agrimophol contentsin Agrimonia pilosa Ledeb. at different harvest time, so as to select its best harvest time. [Methods] High performance liquid chromatography was used for the determination of agfmophol in A. pilosa Ledeb. at different harvest time in Luzhou. [ Results ] The content of agrimophol could be detected by HPLC. Agrimophol had good linearity in 0.01 - 0.1 mg/ml （ r = 0.999 9 ）, the average recov- ery was 101.5%, and RSD was 1.10%. The content of agrimophol in A. pilosa Ledeb. in Luzhou was 0.010 8% in June, and 0.013 1% in July, much higher than any other months. [ Conclusions] This experiment established a method for detecting the content of agrimophol by HPLC, which is simple, with high precision, high accuracy, good repeatability and recovery. The reasonable harvest time of A. pilosa Ledeb. in Luzhou is June and July.

Variation of Calcium Oxalate (CaOx) Crystals in Porang Corms (Amorphophallus muelleri Blume) at Different Harvest Time

Harvest time is assumed to potentially influence shape and size variation of calcium oxalate (CaOx) crystals;therefore it needs to be observed microscopically. This research used porang corms from the second growing period which were planted to produce the vegetative phase of third growing period. These corms were obtained based on the harvest time had determined. The harvest time was determined, i.e. 1) at two weeks before the plants shed (R0 - 1);2) when the plants shed (R0) and 3) at two weeks after the plants shed (R0 + 1). Slides for microscopic observation were obtained from slices on the edge and center of porang corms. Organ slices were cleared using modified clearing method. Parameters observed were the shape and the size of CaOx crystal. The variations of styloid, prism, druse and raphide crystals found in porang corms at the three harvest time were 1, 2, 3 and 37 variations respectively. The variation of CaOx crystals tended to be same in porang corms at three harvest times. The variation of these crystals tended to be static. It is also known that raphide crystal has the greatest variation amount. On the contrary, styloid crystal has the fewest variation amounts. This abundance of a number of raphide crystal variations is possibly due to its role as a defense mechanism in porang corms.

Effects of Short-cut Flowering Branches on Harvest Time,Yield and Quality of Guire No.82 Mango

[Objectives]To further study the technology of short-cut flowering branches for Guire No.82 Mango,adjust its harvest time,increase yield and improve fruit quality,and increase the economic benefits of mango production.[Methods]The experiment of short-cut flowering branches was carried out for Guire No.82 Mango.[Results]At the initial flowering stage and full flowering stage of the primary inflorescence,with short-cut flowering branches and corresponding cultivation techniques,Guire No.82 Mango was easy to extract regenerated inflorescences.Compared with the control group,the flowering period of the regenerated inflorescences was delayed by 30-35 d and 40-50 d,respectively;the harvest time was delayed by 30 and 40 d,respectively;the yield significantly increased by 1.63 times and 2.25 times,respectively;compared with the control group,the number of fruits with embryo increased significantly,which were 1.39 and 2.25 times of the control,respectively;there was no significant difference in the fruit quality at the harvest time.[Conclusions]Short-cut flowering branches at the initial flowering stage and full flowering stage of the primary inflorescence is an effective measure to delay the marketing time of Guire No.82 Mango.

Quality Analysis and High-Performance Liquid Chromatographic Fingerprint Analysis of New Cultivated Kind of <i>Lonicerae japonicae</i>Flos “Hua Jin 6” from Different Harvest Times

Lonicerae japonicaeFlos (LJF) is widely used in traditional Chinese medicines for the treatment of various diseases, which is now in great demand every year and has a broad development prospect. However, the flowering phase of common LJF varieties is so short, which seriously restricts the development of LJF industry. As a new cultivated kind of Lonicerae japonicae Flos, “Hua Jin 6” has characteristics in long flowering phase and conveniently picking, which makes it have a broad development prospect. The aim of this study is to provide scientific guidance for its suitable harvest period by measuring yield and quality of “Hua Jin 6” from different harvest time. Studies show that flower size had a slowly rising trend from the first day to the seventh day, and then slowly declined or kept stable. There were no significant differences of total phenolic acid contents in different samples from different days, but contents of total flavonoids were on the rise and up to maximum in the ninth day. The contents of total iridoids had an increasing tendency from the first day to the fifth day and then kept relatively stable in other days. We demonstrated that the quality of “Hua Jin 6” is relatively stable and suitable for harvesting in all flower buds white stage in term of HPLC fingerprints. Our findings can make it possible to select the suitable time for different harvest purpose.

Assessing the product quality and biological activities of barley(Hordeum vulgare L.)grasses at different harvest times

Barley(Hordeum vulgare L.)grasses(BG)have attracted considerable interest due to their multiple physiological activities and health benefits.In this paper,eight BG at four different growth stages were collected:seedling,tillering,stem elongation,and heading,and their product qualities and biological activities were examined and studied.Results demonstrated that harvest time obviously influenced proximate composition,surface color,and amino acid profile.Z21 and Z23 harvested at the seedling and early tillering stages,respectively,had higher total phenolic content(TPC)and total flavonoid content(TFC)than the other BG.Moreover,Z21 and Z23 possessed better DPPH radical-scavenging ability,antioxidant capacity,andα-glucosidase inhibitory activity,which were positively correlated with TPC,TFC,and protein and total amino acid contents.Our findings suggested that the early tillering stages were the preferable harvest times for BG with good product quality and biological properties.

The Optimal Time for Harvesting the Seeds of Gui 39722, the Female Parent of a Maize Hybrid Guidan 0810

To determine the optimal time for harvesting the seeds of Gui 39722, which is the female parent of a newly-developed maize hybrid Guidan 0810, the cobs of Gui 39722 were harvested 31 （the first stage）, 34 （the second stage）, 37 （the third stage）, 40 （the fourth stage）, 43 （the fifth stage） and 46 （the sixth stage） d after pollination and oven dried at 38 ~C to constant weight. Then, the 1 000-ker- nel weight, germination rate and the agronomic traits of three-leaf seedlings were measured and compared. The results showed that the seeds of Gui 39722 harvest- ed 43 d after pollination （the fifth stage） had the greatest germination rate, seedling height, vigor index, root dry weight, shoot dry weight and germination potential, and high 1 000-kernel weight （very close to the highest level）, root length, number of roots per seedling and root-shoot ratio. Therefore, 43 d after pollination was the op- timal time for harvesting the seeds of Gui 39722, when the effective accumulated temperature after pollination reached 780.7 ℃ and the ear leaf dried. The seeds harvested at this stage had the highest yield and the best quality. Field sampling revealed that 89.00% to 95.00% （with an average of 91.15%） of the seedlings of six stages of seeds grew well.

Effects of Seed Maturity of Turf-Type Tall Fescue on the Seed Vigor and the Optimal Harvesting Time

By assay of accelerated aging germination, germination index, vigor index, seedling length, seedling weight, electric conductivity, dehydrogenase activity, ATP content and acid phosphoesterase activity during seed development of turf-type tall fescue, the seed vigor of tall fescue were studied. Combining with seed moisture content and yield, the optimal harvesting time of tall fescue was determined. The results indicated that the seed vigor increased continuously along with seed maturity, and the higher seed vigor was achieved at 19th day after perk anthesis and maintained continuously until 31st day after peak anthesis. At 25th day after peak anthesis, the highest yield of 3 533 kg ha-1 and the good quality of seeds of tall fescue were harvested with 32.19% moisture content. From 22nd to 31st day after peak anthesis, the seed yield of 3 300 kg ha-1 and the good quality seeds of tall fescue were harvested with 40 - 12. 43% moisture content, and the span was the optimal harvesting time.

Relationship between Storage Environment and Fruit Quality of a Pear Cultivar Xinli No.7 at Different Picking Time

[Objective] This study aimed to study the effects of different picking time and storage environment on fruit quality of a pear cultivar Xinlin No.7 and the relationship between storage environment and fruit quality, so as to provide a theoretical basis for storage and preservation of Xinli No.7. [Method] The fruits of Xinli NO.7 were picked up in August （optimal） and September respectively and then stored in room, cellar and freezer, respectively. The dynamics in temperature, humidity, CO2 concentration, fruit weight loss rate, pericarp chlorophyll content and fruit interior quality were determined. [Result] The environment differed significantly among different storage methods. In room and cellar, the temperature showed a downward trend, and the humidity decreased after early-mid October. The CO2 concentration changed steadily, and increased rapidly in cellar after December. In freezer, the temperature and humidity changed steadily, and the CO2 concentration increased after October. The changes in quality of the fruits harvested in August and September were similar. There was a certain correlation between storage environment and fruit quality of Xinli No.7. In room and cellar, the variation trends of tem- perature and humidity were consistent with those of chlorophyll content, fruit hardness and titratable acid content with positive correlations, but were opposite from those of fruit weight loss rate, soluble solids content and soluble sugar content with negative correlations. In freezer, the CO2 concentration was closely related to the changes in fruit quality. Its variation trend was consistent with those of fruit weight loss rate and soluble solids content, but was opposite from those of pericarp chlorophyll content, fruit firmness, soluble sugar content and titratable acid content. The differences in some of the traits reached significant levels （P〈0.05, P〈0.01）. [Conclusion] With the extension of storage time, the temperature, humidity and CO2 concentration changed according to different patterns among different storage methods. The changes in fruit quality of Xinli NO.7 were related to the storage environment, especially to the temperature, to a certain extent.

内蒙古半干旱冷凉地区燕麦与箭筈豌豆混播生产性能及营养价值评价

为筛选出适宜内蒙古半干旱冷凉地区燕麦(Avena sativa)与箭筈豌豆(Vicia sativa)最佳混播组合、比例和刈割期,本研究以燕麦‘蒙饲燕1号’(‘Mengsiyan 1’)、‘蒙饲燕2号’(‘Mengsiyan 2’)、‘青引1号’(‘Qing yin1’)分别和箭筈豌豆混播为研究对象,对不同混播组合和比例的饲草在不同刈割期生产性能、营养品质及土壤养分等指标进行测定分析与综合评价。结果表明:1)不同混播能够显著提高箭筈豌豆的株高、鲜重和干重(P <0.05);以燕麦150 kg·hm^(−2)和箭筈豌豆75 kg·hm^(−2)单播量配比的‘蒙饲燕1号’+箭筈豌豆混播(3:1)在乳熟期、‘蒙饲燕2号’+箭筈豌豆混播(1:1)在乳熟末期干草产量最高;‘青引1号’+箭筈豌豆混播在各刈割期干草产量均低于同期燕麦单播产量。2)不同混播处理粗蛋白含量较燕麦单播基本呈增加趋势,粗蛋白含量从抽穗期、乳熟期到乳熟末期逐渐降低;水溶性碳水化合物(WSC)含量均在乳熟末期达到最高;不同混播组合在1:3的比例下酸性洗涤纤维(ADF)和中性洗涤纤维(NDF)含量均最低。3)燕麦与箭筈豌豆混播能够显著提高土壤有机质和速效氮含量。通过隶属函数法对混播饲草产量与营养品质进行综合评价,各混播组合中‘蒙饲燕1号’+箭筈豌豆混播(1:3)、‘蒙饲燕2号’+箭筈豌豆混播(1:1)和‘青引1号’+箭筈豌豆混播(1:3)分别在乳熟末期刈割隶属综合评价值较高,其中‘蒙饲燕1号’+箭筈豌豆混播(1:3)最佳(0.70)。

2024年全国荔枝生产形势分析与管理建议

据2024年3月底的调查,全国荔枝种植面积785.13万亩,基于成花情况预测2024年全国荔枝总产量178.10万t,比上年减产45.94%。其中,广东87.64万t,广西41.61万t,海南22.81万t,福建11.78万t,云南7.83万t,四川6.43万t,广东、广西减产幅度较大。如以5月之前、5—7月、7月之后作为荔枝早、中、晚熟划分时间节点,今年国家荔枝龙眼产业技术体系综合试验站覆盖区域早、中、晚熟比例为47.1∶41.9∶11.0。分品种产量预测,‘妃子笑’62.85万t,‘黑叶’18.30万t,‘怀枝’9.35万t,‘白糖罂’7.99万t,‘桂味’5.05万t,‘双肩玉荷包’2.61万t,‘大红袍’1.79万t,‘白蜡’1.52万t,‘糯米糍’1.57万t。‘黑叶’‘怀枝’‘桂味’‘糯米糍’‘鸡嘴荔’等中、晚熟品种减产幅度达60%~80%。分析认为,末次秋梢成熟期偏迟和暖冬是影响今年荔枝成花的主要原因,并据此提出了相关管理技术建议。

云南瑞丽4个主栽柑橘品种成熟期果实品质变化规律

【目的】探究云南瑞丽地区主栽柑橘品种成熟期果实品质变化规律,为确定果实适时采收期提供理论依据。【方法】以云南主栽的4个柑橘品种(沃柑、冰糖橙、茂谷柑、W·默科特)为试材,分别从花后150~330 d(2020年8月12日—2021年2月8日)和花后240~405 d(2021年11月8日—2022年4月28日)开始采果,每隔15 d定期采样并测定果实品质。【结果】随着柑橘果实的成熟,4个品种果实单果质量及横、纵径呈先上升后平缓的趋势,沃柑在花后270 d前、冰糖橙在花后255 d前、茂谷柑在花后300 d前、W·默科特在花后285 d前其果实结束快速生长膨大期;2年内,除茂谷柑转色期一致外,W·默科特果皮转色期早于第1年,沃柑和冰糖橙转色期晚于第1年。冰糖橙、沃柑、茂谷柑和W·默科特的可溶性固形物(TSS)质量分数分别在其花后240、315、300、270 d后基本稳定,可滴定酸(TA)质量分数分别在花后180、210、240、240 d后无显著变化。【结论】综合考虑单果质量、横纵径、果皮颜色和内含物质量分数等指标,沃柑在花后315 d、冰糖橙在花后255 d、茂谷柑在花后300 d、W·默科特在花后285 d时果实达到采收成熟度,适宜开始采收。

共生种群的有限时间稳定性分析及最优捕获算法

针对共生种群在有限时间内的最优捕获问题,通过讨论共生种群的有限时间稳定性,并利用Pontryagin极大值原理及Hamilton函数方法,给出共生种群的最优捕获策略.首先,基于养殖过程的数据信息对共生生物生长过程建立非线性模型,并在保证生态环境平衡的条件下,深入分析共生生长过程和共生系统的有限时间稳定性,给出了严格的证明过程;其次,应用基于Lyapunov方法的Pontryagin极大值原理推导出一种最优采收方法,并得到了最优采收解的一般算法;最后,用仿真对比实验结果证明该算法的有效性.

收获时间与留茬高度对桂青贮7号青贮玉米体外消化特性的影响

本试验旨在探究收获时间与留茬高度对桂青贮7号青贮玉米体外消化特性的影响。以桂青贮7号青贮玉米作为试验材料,分别于1/4乳线期、1/2乳线期、3/4乳线期及蜡熟期这4个收获时间以20、30、40、50、60 cm 5个留茬高度进行收割,之后采用青贮罐方法进行青贮,90 d后测定其常规营养成分含量和体外消化特性。结果表明:1)收获时间与留茬高度对青贮玉米中粗脂肪(EE)、钙(Ca)和磷(P)含量均无显著影响(P>0.05);青贮玉米中中性洗涤纤维(NDF)含量随收获时间的延后先下降后回升,随留茬高度的增高而下降,干物质(DM)含量随收获时间的延后而增加;在1/4乳线期收获,留茬高度为30 cm时粗蛋白质(CP)含量显著高于其他留茬高度(P<0.05),留茬高度为40 cm时酸性洗涤纤维(ADF)含量显著高于其他留茬高度(P<0.05);在1/2乳线期收获,留茬高度为40 cm时粗灰分(Ash)含量显著高于留茬高度为20、30、60 cm时(P<0.05);在3/4乳线期收获,留茬高度为30 cm时CP含量显著低于留茬高度为40、50、60 cm时(P<0.05)。2)收获时间与留茬高度对青贮玉米体外发酵3、6、12、24、48 h的产气量、氨态氮浓度和pH以及3、6、24、48 h的干物质降解率无显著影响(P>0.05)。在1/2乳线期收获,留茬高度为40 cm时青贮玉米体外发酵24 h的乙酸(AA)、丙酸(PA)、丁酸(BA)浓度及体外发酵48 h的AA、PA浓度最高,显著高于其他留茬高度(P<0.05);在3/4乳线期收获,留茬高度为50 cm时青贮玉米体外发酵24 h的AA、PA浓度最高,显著高于其他留茬高度(P<0.05)。综上所述,桂青贮7号青贮玉米的适宜收获时间为1/2乳线期,留茬高度为20~40 cm。

栽培密度和收获期对工业大麻“云麻7号”主要农艺性状及花叶产量的影响

为了探明花叶用工业大麻在云南地区种植的最佳栽培密度和收获期,以云南主栽的工业大麻品种“云麻7号”为材料,分别于2019、2020年在云南省曲靖市沾益区进行大田随机区组试验。两年均设置4个栽培密度(0.5、1、2、3万株/hm^(2))和4个收获期(140、150、160、170 d),在收获期测定株高、茎粗、花叶产量、茎秆产量以及CBD含量等指标。于170 d收获时,两年的株高均在密度2万株/hm^(2)下达到最大值,分别为346.8 cm和267.1 cm,两年的茎粗均在密度0.5万株/hm^(2)下达到最大值,分别为44.3 mm和49.3 mm。2019年在140 d收获和3万株/hm^(2)密度条件下,花叶产量达到最大值3375 kg/hm^(2),2020年在170 d收获和2万株/hm^(2)密度条件下,花叶产量达到最大值5426 kg/hm^(2)。2019年在150 d收获和3万株/hm^(2)密度条件下,茎秆产量和地上部总产量均达到最大值,分别为7560 kg/hm^(2)和11014 kg/hm^(2),2020年在170 d收获2万株/hm^(2)密度条件下,茎秆产量达到最大值5632 kg/hm^(2),在170 d收获和3万株/hm^(2)密度下,地上部总产量达到最大值11001 kg/hm^(2)。大麻CBD含量两年均在160 d收获和1万株/hm^(2)密度条件下达到最大值,分别为1.2%和2.4%。栽培密度与收获期能影响工业大麻的花叶产量和CBD含量,栽培密度为3万株/hm^(2)和170 d时收获是“云麻7号”获得高产的重要栽培措施,同时在160 d收获和1万株/hm^(2)密度下栽培是获得高CBD含量的关键因素。

不同采收期山桐子的果实品质分析

【目的】探明不同采收期山桐子果实质量及差异,为山桐子的质量评价、采摘、加工利用、苗木繁育及推广栽植提供参考。【方法】以21 a生山桐子人工林果实为研究对象,对不同成熟度果实的表型性状、含油率、油脂成分和种子萌发情况等进行测定分析。【结果】随果实成熟度的增加,果皮颜色由青绿色变为深红色,果实大小、果形指数、单果鲜质量、含水率、含油率、种子千粒质量、种子发芽率、饱和脂肪酸含量均呈先上升后下降趋势;不饱和脂肪酸表现为先下降后上升的趋势。相关性分析结果显示,果实含油率与果穗宽、单串果穗鲜质量、单穗果实鲜质量、单果鲜质量、果实横径均呈极显著正相关关系(p<0.01)。10月左右山桐子果实成熟度高、单穗果实个数最多,单穗果实鲜质量、单果鲜质量及果实横径均达到最大,含油率较高,为21.87%,不饱和脂肪酸达85.61%,亚油酸含量72.67%,发芽率最高,可达93.33%。【结论】不同采收期山桐子果实品质存在差异。果实用作油脂原料和实生苗繁育材料时,最佳采收期为10月。

名优茶采摘机器人收获试验

研制新一代履带式名优茶采摘机器人并以其为试验对象,在田间进行龙井茶采摘试验,对其检测、定位、末端采摘的精度以及各环节耗时进行试验评估。结果表明,所研制的名优茶采摘机器人检测成功率为88.54%,定位成功率为84.07%,末端采摘成功率为87.22%,整机采摘成功率为61.30%,所采茶叶可满足中端龙井茶要求。单芽采摘时间约1.51 s,1 h可采摘2000多个,基本实现一台机器替代一个工人的采摘效率。

时滞作用下电磁-压电弹性梁的俘能特性分析

在土木工程结构的健康监测、振动控制中,以压电材料为主要部件的传感系统或主动控制系统得到广泛应用,而在实际工程中,压电耦合系统的供能问题亟待解决。所研究电磁-压电弹性梁的俘能系统是由弹性支座梁与压电作动器、传感器和电磁能量采集器共同构成的闭环反馈控制系统,其中电磁能量采集器(ElectromagneticEnergyHar-vester,EMEH)的能量俘获单元的原理是移动磁铁在固定磁铁之间进行往复振荡,在基础激励下移动磁铁的振荡产生电势能,从而在能量俘获线圈口产生电流。根据Hamilton原理建立电磁-压电弹性梁的非线性振动控制方程,通过Galerkin方法得到时滞微分方程组,利用数值仿真分析,研究不同控制参数、系统参数对能量采集效果的影响。研究结果表明:增大移动磁铁质量能有效提高能量采集效率,且对电磁-压电弹性梁主结构的位移响应影响较弱;另一方面,通过调节控制增益和时滞参数,在达到较优控制效果情况下,可使电磁能量采集器具有一定的俘获效能。

石菖蒲生长过程中β-细辛醚积累特征及其饮片品质研究

[目的]基于气相色谱法建立石菖蒲及其挥发油中β-细辛醚的含量测定方法,比较不同产地石菖蒲饮片品质,并研究石菖蒲生长过程中不同药用部位β-细辛醚的积累规律,为合理开发和利用石菖蒲药材资源提供理论依据。[方法]采用水蒸气蒸馏法提取不同产地饮片挥发油,计算挥发油得率;采用气相色谱法测定饮片及其挥发油中β-细辛醚含量;采集不同月份石菖蒲新鲜全草,利用气相色谱法测定不同药用部位中β-细辛醚含量。[结果]不同产地饮片中β-细辛醚含量、挥发油含量以及挥发油中β-细辛醚含量差异较大,四川产地饮片指标含量差异较小;在研究期限内石菖蒲中β-细辛醚含量(以干质量计)2月最高,7月次之;石菖蒲叶基中β-细辛醚含量高于根茎,叶中几乎不含β-细辛醚。[结论]建立的检测方法简便快速、定量准确、重复性好,可用于石菖蒲的质量评价。以挥发油含量和β-细辛醚计,四川产地饮片品质较佳;以β-细辛醚计,石菖蒲在2月、7月采收较佳,根茎和叶基质量较好。