Molecular mechanisms of bitterness and astringency in the oral cavity induced by soyasaponin

The interaction mechanism between soyasaponin(Ssa)and bitter receptors/mucin,as well as the saliva interface behavior of Ssa,were investigated to explore the presentation mechanism of Ssa bitterness and astringency(BA).Strong bitterness arising from high Ssa concentrations(0.5–1.5 mg/mL)had a masking effect on astringency.At Ssa concentrations of 1.0–1.5 mg/mL,Ssa micelles altered the structure of mucin,exposing its internal tryptophan to a more polar environment.At Ssa concentrations of 0.05–1.50 mg/mL,its reaction with mucin increased the aggregation of particles in artificial saliva,which reduced the frictional lubricating properties of oral saliva.Ssa-mucin interactions affected the salivary interfacial adsorption layer,and their complexes synergistically reduced the interfacial tension.Ssa monomers and soyasapogenols bind to bitter receptors/mucin via hydrogen bonding and hydrophobic interactions.Class A Ssa binds more strongly than class B Ssa,and thus likely presents a higher BA.In conclusion,Ssa interacts with bitter receptors/mucin causing conformational changes and aggregation of salivary mucin,resulting in diminished frictional lubricating properties of oral saliva.This,in turn,affects taste perception and gustatory transmission.

Emulsifying property,antioxidant activity,and bitterness of soybean protein isolate hydrolysate obtained by Corolase PP under high hydrostatic pressure

Enzymatic hydrolysis of proteins can enhance their emulsifying properties and antioxidant activities.However,the problem related to the hydrolysis of proteins was the generation of the bitter taste.Recently,high hydrostatic pressure(HHP)treatment has attracted much interest and has been used in several studies on protein modification.Hence,the study aimed to investigate the effects of enzymatic hydrolysis by Corolase PP under different pressure treatments(0.1,100,200,and 300 MPa for 1-5 h at 50℃)on the emulsifying property,antioxidant activity,and bitterness of soybean protein isolate hydrolysate(SPIH).As observed,the hydrolysate obtained at 200 MPa for 4 h had the highest emulsifying activity index(47.49 m^(2)/g)and emulsifying stability index(92.98%),and it had higher antioxidant activities(44.77%DPPH free radical scavenging activity,31.12%superoxide anion radical scavenging activity,and 61.50%copper ion chelating activity).At the same time,the enhancement of emulsion stability was related to the increase of zeta potential and the decrease of mean particle size.In addition,the hydrolysate obtained at 200 MPa for 4 h had a lower bitterness value and showed better palatability.This study has a broad application prospect in developing food ingredients and healthy foods.

The Effect of Food Thickeners on the Bitterness and Dissolution of Amlodipine Besilate Powder When Co-Administered with Thickeners to Patients with Dysphagia

Purpose: The present research was performed to evaluate the effect of food thickeners on the bitterness and dissolution of bitter drugs when co-administered to patients with dysphagia. Methods: Amlodipine besilate (AMPB) powder was used as a model drug. Starch- and xanthan gum-based food thickeners were examined, with swallowing-aid jelly as a reference. The line-spread test (LST), texture prolife analysis (TPA) were done firstly. In related to AMPB powder mixed with food thickeners solution, a conventional dissolution test simulating the oral cavity was performed, the amlodipine (AMP) concentration and taste sensor output for dissolved medium versus time profiles were developed. The dissolution test at pH 1.2 and 4.5, representing typical gastric conditions for younger or elderly people, was performed in two kinds of thickener solution and swallowing-aid jelly those were mixed with AMPB powder. Results: LST demonstrated that xanthan gum-based food thickeners fulfilled the requirements for patients with dysphagia but that starch-based food thickeners did not. In TPA, hardness and adhesiveness decreased proportionally as the concentration increased for both kinds of food thickener. Conventional dissolution test simulating oral cavity demonstrated the following bitterness ranking: xanthan gum-based food thickener Conclusion: Although xanthan gum-based food thickeners were successful in masking the bitterness of AMP, they may reduce its bioavailability in humans. The 7.1 and 4.7 (w/v) % starch-based thickener show bitterness inhibition under simulated oral cavity conditions and complete dissolution of AMP under simulated gastric conditions.

Evaluation of Bitterness Intensity of Citrus Products by an Untrained Panel Using Relative-to-Reference Rating

In order to estimate the bitterness intensity of citrus products we applied an adaptative sensory evaluation method, using naringin as the reference for bitterness. Twenty-five untrained subjects participated in this study. Firstly they tasted and positioned 2 naringin references on an unstructured relative-to-reference scaling to define their own bitterness scales. They then evaluated the bitterness intensity of 2 types of bitter orange products (3 distillates and 2 cold-pressed essential oils of bitter orange peels) according to their own perceptions on their own scales. We observed that 2 types of scale use could be distinguished that might be related to subjects’ sensitivity or/and consumption habits to bitterness. As a result, we observed a significant difference in bitterness intensity between the crude cold-pressed essential oil and the debittered one of bitter orange, whereas there was no significant difference between the 3 distillates. This approach makes it possible to take inter-individual differences in subjects’ sensitivity into account. It also provides a way to very simply rate bitterness intensity with subjects who have received no prior training in sensory evaluation.

Screening Germplasm Resources of Tea Plant with Less Bitterness and Astringency Index

The aim of this study was to identify tea varieties with less bitterness and astringency index that could be used as important sources for breeding and in the production of high quality tea. We studied 36 cultivars or lines which had been preserved in Tea Germplasm Garden of Fujian. The contents of catechins in spring tea shoots, summer tea shoots and autumn tea shoots in 36 varieties and lines were analyzed by HPLC. Analysis of these tea varieties and lines revealed that the catechins contained in the tea shoots in different seasons are highly variable. The content of ester-catechins in spring and summer tea shoots was higher than that of autumn, while non-ester-catechins did not showed the same characteristic. The content of EGCG showed an extremely significant positive correlation with T1 （T1 = EGC ＋ EGCG ＋ GCG ＋ EGC）, an extremely significant negative correlation with DL-C, the content of EGC showed the same characteristic. Among them, 10 cultivars with less bitterness and astringency index （the annual average bitterness and astringency index 〈 8.0） were considered good candidates as important breeding materials tbr tea infusion quality improvement.

The Effect of Food Thickeners on the Bitterness and Dissolution of Amlodipine Besilate Loaded Oral Disintegration Tablets: Assessment of Potential Suitability for Patients with Dysphagia

The purpose of this research was to evaluate the effect of starch- and xanthan gum-based food thickeners on the bitterness and dissolution of amlodipine besilate (AMPB) loaded orally disintegrating tablets (ODT) for potential use with patients with dysphagia. A conventional dissolution test simulating the oral cavity was performed and the taste sensor output of the dissolved sample was evaluated over a 60-seconds period. When four types of AMPB loaded ODTs were tested alone, at 60 seconds, branded product (A) was the least bitter, followed by generic product (B)/generic product (C) which were equal, and finally generic product (D) which was the most bitter. Inhibition of bitterness of AMPB loaded ODTs mixed thickeners, 1.0 (w/v) % xanthan gum-based food thickener solution was significantly strong. The 7.1 (w/v) % and 4.7 (w/v) % starch-based food thickeners solution also effective in bitterness inhibition compared to the 2.4 (w/v) % starch-based food thickener solution. The dissolution test under pH 1.2 in related to 7.1 (w/v) % and 4.7 (w/v) % starch-based thickener contained each of AMPB loaded ODTs were associated with an almost complete amlodipine (AMP) dissolution (almost 90% at 10 minutes), whereas the 1.0, 2.0, 3.0 (w/v) % xanthan gum-based food thickener solution containing AMPB loaded ODTs did not show complete AMP dissolution and there were large variations in the initial dissolution stage. This suggests that a mixture of xanthan gum-based thickener and AMPB loaded ODT poses a risk of reduction of bioavailability. In conclusion, a mixture of 4.7 (w/v) % or 7.1 (w/v) % starch-based thickener with ODTs provides complete release of AMP and superior bitterness inhibition, so is the best choice for administration to patients with dysphagia.

Role of bitter contributors and bitter taste receptors:a comprehensive review of their sources,functions and future development

Bitterness,one of the 5“basic tastes”,is usually undesired by humans.However,abundant literature reported that bitter fruits and vegetables have beneficial health effects due to their bitter contributors.This review provided an updated overview of the main bitter contributors of typical bitter fruits and vegetables and their health benefits.The main bitter contributors,including phenolics,terpenoids,alkaloids,amino acids,nucleosides and purines,were summarized.The bioactivities and wide range of beneficial effects of them on anti-cancers,anti-inflammations,anti-microbes,neuroprotection,inhibiting chronic and acute injury in organs,as well as regulating behavior performance and metabolism were reported.Furthermore,not only did the bitter taste receptors(taste receptor type 2 family,T2Rs)show taste effects,but extra-oral T2Rs could also be activated by binding with bitter components,regulating physiological activities via modulating hormone secretion,immunity,metabolism,and cell proliferation.This review provided a new perspective on exploring and explaining the nutrition of bitter foods,revealing the relationship between the functions of bitter contributors from food and T2Rs.Future trends may focus on revealing the possibility of T2Rs being targets for the treatment of diseases,exploring the mechanism of T2Rs mediating the bioactivities,and making bitter foods more acceptable without getting rid of bitter contributors.

The role of the auxin-response genes MdGH3.1 and MdSAUR36 in bitter pit formation in apple

Apples often exhibit bitter pits in response to metabolic disorders during ripening and storage;however, the mechanisms underlying the bitter pit(BP) development remain unclear. Here, metabolome and transcriptome analyses were performed to investigate BP pulp of 'Fuji'. Two auxin-response genes, MdGH3.1 and MdSAUR36, were screened. Their expression as well as the auxin content in BP pulp were found to be higher than those in healthy pulp(P < 0.01). In the field, excess CO(NH2)2increased the incidence of BP. Moreover, the auxin content and MdGH3.1 expression increased in apples after nitrogen fertilization. On Day 30 before harvest, the two genes were transiently transferred to the fruit, and 20.69% and 23.21% of BP fruits were harvested. After 10 μmol·L-1auxin was infiltrated at low pressure into postharvest fruit, the increase in MdGH3.1 expression occurred earlier than that in MdSAUR36. MdGH3.1 increased the expression of MdSAUR36, but MdSAUR36 did not increase expression of MdGH3.1. Therefore, we suggest that MdGH3.1 acts upstream of MdSAUR36 during BP formation and that these genes induce BP formation by regulating auxin and phenylpropanoid biosynthesis.

A 1-bp deletion in the MC04g1399 is highly associated with failure to produce fruit wart in bitter gourd

Fruit wart is an important appearance trait influencing consumer preferences of bitter gourd(Momordica charantia L.).The molecular genetic mechanisms underlying fruit wart formation in bitter gourd are largely unknown.In this study,genetic analysis based on four generations showed that fruit wart formation in bitter gourd was controlled by a single dominant locus named as Fwa.The Fwa locus was initially mapped into a 4.82 Mb region on pseudochromosome 4 by BSA-seq analysis and subsequently narrowed down to a 286.30 kb region by linkage analysis.A large F2population consisting of 2360 individuals was used to screen recombinants,and the Fwa locus was finally fine mapped into a 22.70 kb region harboring four protein-coding genes through recombination analysis.MC04g1399,encoding an epidermal patterning factor 2-like protein,was proposed as the best candidate gene for Fwa via sequence variation and expression analysis.In addition,a 1-bp insertion and deletion(InDel)variation within MC04g1399 was converted to a cleaved amplified polymorphic sequence(CAPS)marker that could precisely distinguish between the warty and non-warty types with an accuracy rate of 100%among a wide panel of 126 bitter gourd germplasm resources.Our results not only provide a scientific basis for deciphering the molecular mechanisms underlying fruit wart formation but also provide a powerful tool for efficient genetic improvement of fruit wart via marker-assisted selection.

Genetic mutation of Tas2r104/Tas2r105/Tas2r114 cluster leads to a loss of taste perception to denatonium benzoate and cucurbitacin B

Background:Bitter taste receptors(Tas2rs)are generally considered to sense various bitter compounds to escape the intake of toxic substances.Bitter taste receptors have been found to widely express in extraoral tissues and have important physiological functions outside the gustatory system in vivo.Methods:To investigate the physiological functions of the bitter taste receptor cluster Tas2r106/Tas2r104/Tas2r105/Tas2r114 in lingual and extraoral tissues,multiple Tas2rs mutant mice and Gnat3 were produced using CRISPR/Cas9 gene-editing technique.A mixture containing Cas9 and sgRNA mRNAs for Tas2rs and Gnat3 gene was microinjected into the cytoplasm of the zygotes.Then,T7EN1 assays and sequencing were used to screen genetic mutation at the target sites in founder mice.Quantitative real-time polymerase chain reaction(qRT-PCR)and immunostaining were used to study the expression level of taste signaling cascade and bitter taste receptor in taste buds.Perception to taste substance was also studied using twobottle preference tests.Results:We successfully produced several Tas2rs and Gnat3 mutant mice using the CRISPR/Cas9 technique.Immunostaining results showed that the expression of GNAT3 and PLCB2 was not altered in Tas2rs mutant mice.But qRT-PCR results revealed the changed expression profile of m Tas2rs gene in taste buds of these mutant mice.With two-bottle preference tests,these mutant mice eliminate responses to cycloheximide due to genetic mutation of Tas2r105.In addition,these mutant mice showed a loss of taste perception to quinine dihydrochloride,denatonium benzoate,and cucurbitacin B(CuB).Gnat3-mediated taste receptor and its signal pathway contribute to CuB perception.Conclusions:These findings implied that these mutant mice would be a valuable means to understand the biological functions of TAS2Rs in extraoral tissues and investigate bitter compound-induced responses mediated by these TAS2Rs in many extraoral tissues.

In the Shadow of Suku （Speaking-Bitterness）： Master Scripts and Women＇s Life Stories

This article explores the enduring effect of a narrative model known as suku （＂speaking bitterness＂） in the post-Mao era, and in particular its gendered effect when women adopted it to represent their own lives. Using the oral life-story of a woman who lived through the Mao era as an example, the article explores the ways suku operates as a master script in people＇s narratives about their lives. It argues that the adoption of the model in a certain sense resulted in the de-narration of gendered experience, as well as the de-narration of life in the post-Mao era, it further demonstrates that the suku narrative model limited not only the representation of certain experiences but also the construction of gender subjectivity. Furthermore, in the post-Mao era, instead of being the master script, the suku model often has to negotiate with other scripts, being revised, extended, redirected, and in some cases, replaced. One of these encounters, between the suku model and a feminist script, will be examined. The article argues that such encounter has the potential to challenge the master script and to create narrative space for women to narrate their gendered experience, and to construct a self-defined, more adequately articulated gender subjectivity.

A novel quantified bitterness evaluation model for traditional Chinese herbs based on an animal ethology principle

Traditional Chinese herbs(TCH) are currently gaining attention in disease prevention and health care plans. However, their general bitter taste hinders their use. Despite the development of a variety of taste evaluation methods, it is still a major challenge to establish a quantitative detection technique that is objective, authentic and sensitive. Based on the two-bottle preference test(TBP), we proposed a novel quantitative strategy using a standardized animal test and a unified quantitative benchmark. To reduce the difference of results, the methodology of TBP was optimized. The relationship between the concentration of quinine and animal preference index(PI) was obtained. Then the PI of TCH was measured through TBP, and bitterness results were converted into a unified numerical system using the relationship of concentration and PI. To verify the authenticity and sensitivity of quantified results,human sensory testing and electronic tongue testing were applied. The quantified results showed a good discrimination ability. For example, the bitterness of Coptidis Rhizoma was equal to 0.0579 mg/mL quinine, and Nelumbinis Folium was equal to 0.0001 mg/mL. The validation results proved that the newassessment method for TCH was objective and reliable. In conclusion, this study provides an option for the quantification of bitterness and the evaluation of taste masking effects.

Influence of Tea Leaf Particle Size on Catechin Extraction and Green Tea Sensory Acceptance

The intensity of the bitterness of catechins increases with increased concentration, but the taste palatability decreased in green tea extract. The aim of this study was to investigate whether a blend of tea leaf particles of various sizes would result in a good balance between catechin content and appreciable taste. The control is common tea (CT) with 6 - 10 mm long leaves. Blend tea (BT) was prepared by mixing 5 mm and 120 - 130 mm long tea leaves in a ratio of 3:2. The catechin content of hot water extracts was analyzed by HPLC, and the sensory test was conducted with 99 volunteers. In BT, the total catechin content was significantly higher than that in CT. The sensory test results revealed that BT was less bitter and had more preferable color than CT. More catechins were extracted from BT, but it tasted less bitter. Thus, the recalibration of the tea leaf particle size can result in good balance between catechin content and palatability.

Discovery of the relationship between bitter taste and bitter flavor (efficacy) based on hTAS2Rs

Objective:To explore the relationship between bitter taste and bitter flavor(efficacy),their character-istics were analyzed at the target and pharmacodynamic points.Methods:Compounds with bitter receptor activity were obtained by high-throughput screening models of the human bitter taste receptors(hTAS2Rs),which were used to analyze bitter taste.The efficacy of anti-asthma medications was used as an example to research bitter flavor(efficacy).The pharmacological effects of bitter taste and bitter flavor(efficacy)were classified according to the functional modules.The coverage for the same targets or pharmacological effects in the overall protein interaction network(PIN)of bitter taste and bitter flavor(efficacy)was analyzed to reveal their relationship.The effect of the compound polydatin with anti-asthma activation on hTAS2R14 was studied to verify the reliability of the aforementioned idea.Results:A total of 121 Chinese materia medica(CMM)compounds that activate hTAS2R10,hTAS2R14,and hTAS2R49 were obtained.The analysis results indicated that 108 same targets for bitter taste and bitter flavor(efficacy)were obtained,accounting for 13.9%in the PIN of bitter taste and 72.5%in the PIN of bitter flavor(efficacy).The pharmacological effects shared by bitter taste and bitter flavor(efficacy)accounted for 79%of the PIN of bitter taste and 81%of the PIN of bitter flavor(efficacy).The activating effect of the anti-asthma compound polydatin on hTAS2R14 was dose-dependent with EC 50 of 4.3 m M.Conclusion:In this study,the relationship between bitter taste and bitter flavor(efficacy)has been demonstrated from the target and pharmacodynamic points,which are based on hTAS2Rs and anti-asthma effect.Bitter taste and bitter flavor(efficacy)exhibited a high correlation.This study provides a theoretical and scientific basis for the hypothesis that“the property theory of CMM is the clinical pharmacodynamics of CMM.”

Genetic Analysis of the First Female Flower Node and the First Male Flower Node in Bitter Gourd

Exploring genetic mechanism of the first female flower node and the first male flower node in bitter gourd has practical significance for formulating breeding strategy. In this article, a cross was made between CN19-1 and Thai4-6, and the F2segregation population was also constructed through F1selfing. The genetic characteristics of the first female flower node and the first male flower node were analyzed by adopting the major gene plus polygene mixed genetic model. The data analysis results showed that the first female flower node and the first male flower node were continuous distribution in the F2segregation population. E-2 model was the most suitable model for the genetic analysis of the first female flower node and the first male flower node. The additive effect values of the 2 pairs of major genes controlling the first female flower node were 2.722 and 1.862 8 respectively, the dominant effect values were-2.721 6 and-0.171 8, respectively. The additive effect value of polygene was-0.839 2, and the dominant effect value of polygene was 2.225 4. The heritability of major genes and polygene were 83.73% and 1.54%, respectively. The additive effect values of the 2 pairs of major genes controlling the first male flower node were 17.746 9 and 3.972, respectively, the dominant effect values were 5.191 6 and-3.972, respectively. The additive effect value of polygene was-20.530 5, and the dominant effect value was-4.141 4. The heritability of major genes and polygene was 92.34% and 4.7%, respectively. This study could provide a theoretical basis for bitter gourd breeding.

Exploring the mechanism of action bitter melon in the treatment ofbreast cancer by network pharmacology

BACKGROUND Bitter melon has been used to stop the growth of breast cancer(BRCA)cells.However,the underlying mechanism is still unclear.AIM To predict the therapeutic effect of bitter melon against BRCA using network pharmacology and to explore the underlying pharmacological mechanisms.METHODS The active ingredients of bitter melon and the related protein targets were taken from the Indian Medicinal Plants,Phytochemistry and Therapeutics and SuperPred databases,respectively.The GeneCards database has been searched for BRCA-related targets.Through an intersection of the drug’s targets and the disease’s objectives,prospective bitter melon anti-BRCA targets were discovered.Gene ontology and kyoto encyclopedia of genes and genomes enrichment analyses were carried out to comprehend the biological roles of the target proteins.The binding relationship between bitter melon’s active ingredients and the suggested target proteins was verified using molecular docking techniques.RESULTS Three key substances,momordicoside K,kaempferol,and quercetin,were identified as being important in mediating the putative anti-BRCA effects of bitter melon through the active ingredient-anti-BRCA target network study.Heat shock protein 90 AA,proto-oncogene tyrosine-protein kinase,and signal transducer and activator of transcription 3 were found to be the top three proteins in the proteinprotein interaction network study.The several pathways implicated in the anti-BRCA strategy for an active component include phosphatidylinositol 3-kinase/protein kinase B signaling,transcriptional dysregulation,axon guidance,calcium signaling,focal adhesion,janus kinase-signal transducer and activator of transcription signaling,cyclic adenosine monophosphate signaling,mammalian CONCLUSION Overall,the integration of network pharmacology,molecular docking,and functional enrichment analyses shed light on potential mechanisms underlying bitter melon’s ability to fight BRCA,implicating active ingredients and protein targets,as well as highlighting the major signaling pathways that may be altered by this natural product for therapeutic benefit.

Distribution of Calcium in Bagged Apple Fruit and Relationship between Antioxidant Enzyme Activity and Bitter Pit

[Objective]The aim was to study the distribution of Ca in bagged apple fruit and the relationship between antioxidant enzyme activity and bitter pit disease,which will provide a basis for resolving Ca metabolism disorder in apple cultivation. [Method]With Fuji Apple as the tested material,the changes of Ca2＋ content and antioxidant enzyme activity in different parts of apple fruit after picking bags and storage period were determined. [Result]The results showed that Ca contents in the light surface of fruits were higher than that in the backlight surface. The Ca contents of stalk cavity were higher than that of calyx-end. The activities of SOD,POD,CAT and APX in the light surface of fruits were higher than that in the backlight surface. The activities of SOD,POD,CAT and APX of stalk cavity were higher than that of calyx-end. The contents of MDA in the light surface of fruits were lower than that in the backlight surface. The contents of MDA of stalk cavity were lower than that of calyx-end. [Conclusion]The incidence rate of bitter pit in the light surface of fruits were lower than that in the backlight surface,and the incidence rate of bitter pit of stalk cavity were lower than that of calyx-end.

Analysis and Evaluation of Biochemical Components in Bitter Tea Plant Germplasms

Bitter tea is a special kind of tea germplasm in China.The major biochemical components of 24 bitter teas and other 8 Camellia sinensis var.sinensis and 8 C.sinensis var.assamica tea germplasms,which were stored in the China National Germplasm Hangzhou Tea Repository(CNGHTR),were analyzed and evaluated.The results showed that no significant differences of major biochemical components affecting the tea quality were found between bitter tea and common tea.According to the processing suitability index,bitter tea was suitable for the manufacturing of black tea;while according to evolutionary indices such as the composition and content of catechin,bitter tea was similar to C.sinensis var.assamica belonging to the relatively primitive type in evolution.The results of cluster analysis indicated that bitter tea was clustered with C.sinensis var.assamica,so it could be considered to belong to C.sinensis var.assamica.

Study on Genetic Diversity of Agronomic Traits and Genetic Relationships among Core Collections of Bitter Gourd

[Objective] This study aimed to investigate the genetic diversity of agronomic traits and genetic relationships among core collections of bitter gourd.[Method] Total 141 germplasms of bitter gourd were selected,and the genetic diversity of 13 agronomic traits was analyzed.In addition,total 46 core collections of bitter gourd were employed,and their genetic relationships were analyzed based on the phenotypic values and genotypic values of 5 agronomic traits,respectively.[Result] The genetic diversity analysis of agronomic traits showed that the genetic diversity indexes of the 4 qualitative traits of bitter gourd germplasms ranged from 0.46 to 1.34;the distribution of the 9 quantitative traits data was more dispersed with average coefficient of variation of 20.02%.The genetic relationship analysis showed that based on the phenotypic values and genotypic values of the 5 quantitative traits,the genetic distances among the 46 core collections of bitter gourd were different.Based on the genotypic values,the genetic distances among the 46 bitter gourd core collections ranged from 0.84 to 10.71.The 46 germplasms were divided into 17 groups with the rescaled distance of 8.5,which further classified the relationships among different germplasms.[Conclusion] This study will lay a solid foundation for the effective utilization of core collections and new variety breeding in bitter gourd.

地磁场中应力对磁畴组织的影响

研究了地磁场环境中应力对铁磁性材料磁畴结构的影响规律。利用Bitter粉纹法观察了未经磁化、受力程度不同的无取向硅钢片和20钢试件的磁畴结构,对比分析了应力对磁畴的影响。结果表明,铁磁试件应力集中部位的磁畴结构在应力作用下发生改变。未受力或应力集中较小时,晶粒内磁畴以片状畴为主,同一晶粒内畴壁相互平行,随着应力集中程度增加,畴壁长度和间距发生改变,并且磁畴结构出现迷宫畴,应力集中程度越大,迷宫畴数量越多。同时,拉应力和压应力对磁畴结构的影响规律不同。