PEG-6000模拟干旱胁迫下云麦77和云麦80的萌发特征和抗旱性评价

云南冬春干旱严重影响小麦的生长发育和产量,研究小麦新品种的萌发特征及其抗旱性评价对小麦新品种示范推广具有重要的指导意义。应用不同质量浓度的PEG-6000溶液处理云南不同栽培模式下的小麦新品种云麦77(地麦)与云麦80(田麦),分别测试其种子日相对发芽率、萌发率、发芽势、萌发时滞、萌发系数、种子萌发抗旱指数及游离脯氨酸含量(质量浓度)。结果表明:PEG-6000质量浓度大于6 g/L时,云麦80不能萌发,云麦77能够发芽,但萌发时间延后;不同质量浓度的PEG-6000溶液对2种不同小麦新品种日相对发芽率、发芽势、萌发时滞、萌发系数、种子萌发抗旱指数的抑制差异明显,其中萌发率、发芽势、萌发系数总体随着PEG-6000浓度的增加而降低,且在2—8 g/L PEG-6000溶液的胁迫下,云麦77的萌发率和萌发系数高于云麦80;在无PEG-6000处理下,云麦80游离脯氨酸含量显著高于云麦77;在相同质量浓度(10 g/L除外)PEG-6000处理下,云麦77游离脯氨酸含量均高于云麦80。通过模拟抗旱检测小麦品种抗旱性的方法有效,云麦77抗旱性强,可作为云南主推旱地麦新品种推广应用。

PEG6000模拟干旱胁迫对铁皮石斛幼苗生理和叶绿素荧光特性的影响

【目的】研究聚乙二醇6000(PEG 6000)模拟干旱对铁皮石斛Dendrobium candidum生理和叶绿素荧光特性的影响,为铁皮石斛的品种选育、产业化栽培和近野生栽培等提供参考。【方法】以铁皮石斛‘晶品1号’D.candidum‘Jingpin No.1’幼苗为实验材料,通过不同质量分数PEG 6000(5%、10%、20%、30%)模拟干旱胁迫处理铁皮石斛幼苗,观察铁皮石斛幼苗茎段和叶片细胞结构,并检测铁皮石斛叶片过氧化物酶(POD)、过氧化氢酶(CAT)活性及丙二醛(MDA)质量摩尔浓度、可溶性糖质量分数、可溶性蛋白质量分数、叶绿素质量分数及叶绿素荧光参数的动态变化。【结果】①高质量分数PEG 6000(20%-30%)处理后铁皮石斛茎段和叶片细胞内叶绿素质量分数减少。②PEG 6000模拟干旱胁迫处理对铁皮石斛幼苗可溶性糖和可溶性蛋白、MDA、POD和CAT有显著影响(P<0.05)。可溶性糖质量分数随着PEG 6000质量分数的增加和处理时间的延长均呈上升趋势,到第12天时达最高值;可溶性蛋白则呈下降趋势;MDA质量摩尔浓度、POD活性和CAT活性随着PEG 6000质量分数的增加呈先上升后下降的趋势,在PEG 6000为20%时达到峰值。③PEG 6000模拟干旱处理对铁皮石斛幼苗最大光化学效率(F_(v)/F_(m))、光合效率(α)、电子传递速度(ETR)、光化学猝灭系数(q_(P))和非化学猝灭系数(qNP)等叶绿素荧光参数有显著的影响(P<0.05)。随着PEG 6000胁迫处理时间的延长和PEG 6000质量分数的增加,α、ETR、F_(v)/F_(m)和q_(P)均呈显著下降趋势(P<0.05);而qNP则呈先上升后下降的趋势。【结论】20%PEG 6000处理12 d可用作铁皮石斛抗干旱品种的筛选,铁皮石斛幼苗可通过增加可溶性糖质量分数,减少可溶性蛋白质量分数,提高POD和CAT活性等防御酶活性抵抗和适应一定程度的干旱胁迫;铁皮石斛幼苗的最大光能转换效率降低,光合系统Ⅱ(PSⅡ)受到胁迫损伤,严重影响铁皮石斛幼苗的光合作用。同时,铁皮石斛幼苗通过启动qNP途径来消耗PSⅡ反应中心吸收的过剩光能,维持正常的光合作用。因此,可溶性糖和可溶性蛋白、POD和CAT以及叶绿体荧光参数均可作为铁皮石斛耐干旱的指标。

PEG模拟干旱胁迫对加拿大飞蓬种子萌发及幼根生长的影响

【目的】研究干旱胁迫对加拿大飞蓬种子萌发及幼根生长的影响,为科学防控加拿大飞蓬入侵提供依据。【方法】以当年生加拿大飞蓬成熟种子为材料,分别用蒸馏水(CK)和不同浓度5%、10%、15%、20%、25%的聚乙二醇溶液(PEG)(分别表示轻度、中度、重度、极度和极重度干旱胁迫强度)对加拿大飞蓬种子进行处理。测定日相对发芽率、发芽率、发芽势等指标,分析加拿大飞蓬种子萌发情况;测定幼苗根系宽、根系高、根平均直径、根面积、总根尖数及根分叉数,分析其幼苗根生长情况;并测定种子恢复萌发情况。【结果】无干旱胁迫的加拿大飞蓬种子萌发指标最高,随着干旱胁迫强度增加,种子萌发指标减小,极重度干旱胁迫下加拿大飞蓬种子不萌发。与CK相比,轻度干旱胁迫和重度干旱胁迫对加拿大飞蓬根平均直径影响不显著,但会促进侧根与不定根生长;重度干旱胁迫下,加拿大飞蓬的总根尖数和分叉数显著增加。加拿大飞蓬种子在PEG浓度为20.13%的干旱胁迫下不发芽。种子在极度和极重度干旱胁迫下不萌发,但当水分条件充足时,种子依然具有萌发的能力。【结论】建议在加拿大飞蓬种子尚未成熟前进行人工拔除,或在加拿大飞蓬入侵地种植耐旱强、生长快、根系发达、竞争性强的植物,以控制加拿大飞蓬的生长发育。

钛粉末注射成形PEG/PMMA黏结剂体系的PHB改性研究

金属注射成型(MIM)中使用水溶性聚乙二醇(PEG)和聚甲基丙烯酸甲酯(PMMA)黏结剂体系会导致大量孔洞形成,该黏结剂体系导热性差,使得零件尺寸越大,注射脱模时间越长。用聚(β-羟基丁酸酯)(PHB)作为PEG结晶抑制剂可解决上述问题。采用导热系数仪、DSC、流变学实验、傅里叶变换红外光谱(FTIR)等,研究PHB含量对黏结剂导热系数、结晶行为、喂料流变特性、注射保压时间及生坯显微结构的影响。结果表明:PHB/PEG共混物随着PHB含量的增加,结晶温度从纯PEG的55.18℃下降至25%(质量分数,下同)PHB改性的51.4℃,熔融焓从79.5 J/g逐渐增加至107.6J/g,导热系数从0.2433 W·m^(-1)·K^(-1)适当增加至0.3469 W·m^(-1)·K^(-1),黏结剂结晶度的增加可改善其导热性能;由于PEG/PHB/PVAc三元体系中存在复杂氢键的相互作用,导致黏结剂结晶温度从未添加PHB的50.07℃降低并稳定在添加25%PHB的43.3℃;添加15%PHB后制备的喂料黏度与剪切速率符合幂律流体规律,在120℃时喂料的剪切稀化指数从未改性的0.77减小至0.62,相同注射条件下注射脱模时间从未改性的100 s缩短至50 s便可获得表面光滑无裂纹、内部孔洞少且分布均匀的钛注射生坯。

PEG渗透胁迫下藏沙蒿种质资源萌发特性及抗旱性评价

【目的】评价藏沙蒿野生种质材料萌发期抗旱性。【方法】以采自西藏地区不同生境的13份藏沙蒿(Artemisia wellbyi)种质材料为研究对象,设置聚乙二醇(PEG⁃6000)浓度梯度分别为0、-0.20、-0.40、-0.60和-0.86 MPa共5个渗透胁迫处理,研究PEG⁃6000渗透胁迫对藏沙蒿材料萌发特性的影响,并采用主成分分析和隶属函数两种方法对其抗旱性进行综合评价。【结果】PEG渗透胁迫降低了藏沙蒿种子的相对发芽势、相对发芽率、相对活力指数和萌发胁迫指数。藏沙蒿在受到干旱胁迫时通过推迟发芽时间、抑制芽长和促进根长来应对干旱胁迫。通过主成分分析,筛选出相对发芽势、相对发芽率、相对根长、相对活力指数和萌发胁迫指数5个抗旱性指标。【结论】主成分分析和隶属函数法综合评价认为,抗旱性较强的种质材料为5、11和4号,抗旱性较弱的为13号材料。

PEG/漂珠复合相变材料的表征及性能研究

为了研发适用于高温环境下沥青路面的复合相变材料,本研究以PEG2000作为相变材料,漂珠作为载体,利用PEG2000优良的相变特性及漂珠的高强度特性,制备出一种高强度且耐高温的复合相变材料(composite phase change materials,CPCMs)。制备的CPCMs在相变储热性能上表现较好,同时具有优良的化学稳定性、兼容性及热稳定性。当CPCMs的掺量达到60%时,测温试件之间的最高温差仅为2.8℃,峰值温度出现的时间延迟了2.1 min,对路用性能也产生了不利影响。因此,适量CPCMs能够有效调控沥青混合料温度。该研究结果为沥青路面的降温调控提供了参考。

PEG介导的广东虫草原生质体遗传转化体系建立及其应用

【目的】广东虫草是我国特有珍稀食药用菌,其营养成分丰富、活性功效显著,已获批新资源食品,产业化应用前景广阔。建立广东虫草原生质体制备及遗传转化方法,可为广东虫草新品种选育及基因功能研究提供参考依据。【方法】以广东虫草菌丝体为材料,采用单因素分析方法对原生质体制备过程中酶解组合、酶解时间、酶解温度、复苏培养基及抗性标记进行筛选。同时以潮霉素抗性标记质粒pCAMBIA1300为转化片段,采用单因素分析方法对PEG介导的原生质体转化过程中亚精胺浓度、PEG加入间隔时间、抗生素添加时间进行筛选。并以广东虫草中的锌指半胱氨酸转录因子CgPro1敲除片段为目的转化片段,对转化系统进行验证。【结果】广东虫草原生质体制备的最佳组合条件为:采用含有裂解酶+崩溃酶的混合酶体系(1∶1)对广东虫草的菌丝体进行酶解,且酶解温度28℃、酶解时间为5.5 h时原生质体得率最高;原生质体复苏过程中,TB3复苏培养基对广东虫草原生质体的复苏效果最好、其次为0.6mol/L KCl-PDA;PEG介导原生质体转化过程中,加入5 mmol/L亚精胺、PEG加入间隔时间10 min、原生质体复苏3 d后添加250μg/mL潮霉素抗性标记进行筛选,转化效率最高。此外,通过建立的转化系统获得3个CgPro1敲除突变株及3个杂合子,表型分析结果显示,该基因参与广东虫草子实体发育过程。【结论】建立了成熟的广东虫草原生质体制备及PEG介导的遗传转化体系,可为今后广东虫草基因功能、蛋白定位等遗传操作研究奠定良好基础,同时为广东虫草遗传育种提供重要应用参考。

PEG-6000处理下3种薹草种子萌发期的耐旱性评价

以低矮薹草、矮丛薹草、大披针薹草的种子为试验材料,分别用质量分数0%(CK)、5%、10%、15%、20%、25%PEG-6000溶液进行处理,通过测定发芽率、发芽势、发芽指数和活力指数,评价3种薹草种子在萌发期的耐旱性。结果表明:随着PEG-6000质量分数的升高,3种薹草种子的发芽率、发芽势、发芽指数、活力指数均受到不同程度的影响。3种薹草种子耐旱性由强到弱依次为:大披针薹草>矮丛薹草>低矮薹草。

PEG嵌段共聚物整理棉织物的自清洁性能研究

探讨PEG嵌段共聚物整理棉织物的自清洁性能。通过原子转移自由基聚合的方法合成聚乙二醇嵌段共聚物聚甲基丙烯酸三氟乙酯-b-聚乙二醇-b-聚甲基丙烯酸三氟乙酯(PTFEMA-b-PEG-b-PTFEMA)。对PEG嵌段共聚物的结构进行红外光谱和核磁共振表征。通过“轧-烘-焙”的方法将其整理到棉织物上,对整理前后棉织物的表面形貌和水接触角进行测试,并对整理后棉织物耐水洗和耐摩擦性能、对酸和碱的耐久性能、透气透湿性能、对染料的自清洁性能进行分析。结果表明:整理后棉织物水接触角高达151°,具有超疏水性能;整理后的棉织物具有良好的自清洁性、耐摩擦性能、耐化学稳定性、透气和透湿性能。

Gut microbial metabolite targets HDAC3-FOXK1-interferon axis in fibroblast-like synoviocytes to ameliorate rheumatoid arthritis

Rheumatoid arthritis(RA)is an autoimmune disease.Early studies hold an opinion that gut microbiota is environmentally acquired and associated with RA susceptibility.However,accumulating evidence demonstrates that genetics also shape the gut microbiota.It is known that some strains of inbred laboratory mice are highly susceptible to collagen-induced arthritis(CIA),while the others are resistant to CIA.Here,we show that transplantation of fecal microbiota of CIA-resistant C57BL/6J mice to CIA-susceptible DBA/1J mice confer CIA resistance in DBA/1J mice.C57BL/6J mice and healthy human individuals have enriched B.fragilis than DBA/1J mice and RA patients.Transplantation of B.fragilis prevents CIA in DBA/1J mice.We identify that B.fragilis mainly produces propionate and C57BL/6J mice and healthy human individuals have higher level of propionate.Fibroblast-like synoviocytes(FLSs)in RA are activated to undergo tumor-like transformation.Propionate disrupts HDAC3-FOXK1 interaction to increase acetylation of FOXK1,resulting in reduced FOXK1 stability,blocked interferon signaling and deactivation of RA-FLSs.We treat CIA mice with propionate and show that propionate attenuates CIA.Moreover,a combination of propionate with anti-TNF etanercept synergistically relieves CIA.These results suggest that B.fragilis or propionate could be an alternative or complementary approach to the current therapies.

PEG渗透胁迫下不同品种绿豆萌芽期抗旱性评价

为了探讨聚乙二醇(PEG)渗透胁迫对绿豆萌发的影响,明确干旱胁迫条件下绿豆萌发期的相关各项指标,筛选出抗旱性绿豆品种(系),从而为在绿豆抗旱新品种的筛选过程中提供理论依据,以18个绿豆品种(系)为研究对象,采用浓度为20%的PEG-6000溶液模拟干旱胁迫,对其萌发指标进行测定和分析,并对参试品种的抗旱性采用主成分分析和隶属函数方法进行鉴定和评价。结果表明,与对照相比,20%PEG渗透胁迫绿豆种子后,种子萌发的相关指标都有不同程度的下降,不同品种之间表现出一定的差异性。对6个抗旱性指标进行主成分分析,结果显示,累计贡献率为89.55%,可以有效地反映各数据的变化。18个绿豆品种(系)的综合评价D值为0.389~0.858,依据D值将其聚类分析分为3类,筛选出6个耐旱性品种:晋绿9号、同123-33、同绿5号、同118-6、同绿6号、黄荚绿。通过对18个绿豆品种的抗旱性综合评价,最终得到6个强耐旱品种,3个耐旱品种,9个较敏感品种。萌发期鉴定结果可作为衡量作物抗旱性强弱的一个重要指标,在此基础上,可以进一步结合全生育期的抗旱性评价结果进行综合分析。

Expression level of interferon-stimulated genes PKR,OAS1,MX1,and ISG15 in peripheral blood mononuclear cells of COVID-19 patients:A retrospective study

Objective:To explore expression level of interferon-stimulated genes PKR,OAS1,MX1,and ISG15 in peripheral blood mononuclear cells of COVID-19 patients.Methods:In this study,changes in the expression of four interferon-stimulated genes(ISGs),including PKR,OAS1,MX1,and ISG15,in peripheral blood mononuclear cells of 45 COVID-19 patients with different severities were evaluated by real-time PCR method.Results:OAS1,MX1,PKR,and ISG15 were differently expressed in COVID-19 patients with different severity.The results showed that the expression of OAS1,MX1,PKR,and ISG15 genes was significantly(P=0.001)lower in severe patients.Conclusions:Weak and defective IFN response and subsequent disruption of ISGs may be associated with COVID-19 severity.

Relationship between Phenotypic Changes of Dendritic Cell Subsets and the Onset of Plateau Phase during Intermittent Interferon Therapy in Patients with CHB

Objective This study aimed to evaluate whether the onset of the plateau phase of slow hepatitis B surface antigen decline in patients with chronic hepatitis B treated with intermittent interferon therapy is related to the frequency of dendritic cell subsets and expression of the costimulatory molecules CD40,CD80,CD83,and CD86.Method This was a cross-sectional study in which patients were divided into a natural history group(namely NH group),a long-term oral nucleoside analogs treatment group(namely NA group),and a plateau-arriving group(namely P group).The percentage of plasmacytoid dendritic cell and myeloid dendritic cell subsets in peripheral blood lymphocytes and monocytes and the mean fluorescence intensity of their surface costimulatory molecules were detected using a flow cytometer.Results In total,143 patients were enrolled(NH group,n=49;NA group,n=47;P group,n=47).The results demonstrated that CD141/CD1c double negative myeloid dendritic cell(DNmDC)/lymphocytes and monocytes(%)in P group(0.041[0.024,0.069])was significantly lower than that in NH group(0.270[0.135,0.407])and NA group(0.273[0.150,0.443]),and CD86 mean fluorescence intensity of DNmDCs in P group(1832.0[1484.0,2793.0])was significantly lower than that in NH group(4316.0[2958.0,5169.0])and NA group(3299.0[2534.0,4371.0]),Adjusted P all<0.001.Conclusion Reduced DNmDCs and impaired maturation may be associated with the onset of the plateau phase during intermittent interferon therapy in patients with chronic hepatitis B.

Eudragit®-PEG Nanoparticles: Physicochemical Characterization and Interfacial Tension Measurements

The objectives of this study are to understand the mechanisms involved in the stabilization of water/oil interfaces by polymeric nanoparticles (NPs) (Eudragit®). Eudragit L100 NPs of various sizes and Zeta potentials were studied and compared at a water/cyclohexane model interface using a droplet tensiometer (Tracker Teclis, Longessaigne, France). The progressive interfacial adsorption of the NPs in the aqueous phase was monitored by tensiometry. The model interface was maintained and observed in a drop tensiometer, analyzed via axisymmetric drop shape analysis (ADSA), to determine the interfacial properties. Given the direct relationship between the stability of Pickering emulsions (emulsions stabilized by solid nanoparticles) and the interfacial properties of these layers, different nanoparticle systems were compared. Specifically, Eudragit NPs of different sizes were examined. Moreover, the reduction of the Zeta potential with PEG-6000 induces partial aggregation of the NPs (referred to as NP flocs), significantly impacting the stability of the interfacial layer. Dynamic surface tension measurements indicate a significant decrease in interfacial tension with Eudragit® nanoparticles (NPs). This reduction correlates with the size of the NPs, highlighting that this parameter does not operate in isolation. Other factors, such as the contact angle and wettability of the nanoparticles, also play a critical role. Notably, larger NPs further diminished the interfacial tension. This study enhances our understanding of the stability of Pickering emulsions stabilized by Eudragit® L100 polymeric nanoparticles.

Evaluation of Interferon-Gamma Release Assay Testing and Tuberculin Skin Test for Early Diagnosis of Tuberculosis in Children and Adolescents

Background: This study aimed to evaluate the diagnostic value of interferon-γ release assay (IGRA), a sensitive microbiological diagnostic method, in children and adolescents with suspected tuberculosis in a country with a high burden of tuberculosis. Method: This study included 581 children and adolescents aged 4 - 19 years who were suspected of having tuberculosis, were latently infected with Mycobacterium tuberculosis, and had received at least one dose of BCG vaccine between April 17, 2019, and February 24, 2021. The study evaluated the TST results of 106 patients who had a positive Quantiferon test and were suspected of having tuberculosis. Results: The study included 581 patients aged between 4 and 19 years. Of these, 106 patients tested positive for the Quantiferon test, while 19 were indeterminate and 456 were negative. The Quantiferon test positivity rate was 18.24%. Among the 106 QFT-Plus-positive cases, 23 patients also tested positive for TST. The difference in distribution was found to be statistically significant. Conclusion: The QFT-Plus test is considered an alternative to TST and other microbiological diagnostic methods for early tuberculosis diagnosis, particularly in children and adolescents.

Predictive Value of Serum pgRNA on HBeAg Clearance in Patients with Chronic Hepatitis B with Low HBeAg Levels Treated with Pegylated Interferon

Objective:To study the predictive value of serum pregenomic RNA(pgRNA)on HBeAg clearance in patients with chronic hepatitis B with low HBeAg levels during pegylated interferon therapy.Methods:Twenty chronic hepatitis B patients with HBeAg positive and quantitative<50S/CO were selected for this study.The subjects underwent pegylated interferon therapy for 48-96 weeks and were followed up in the outpatient clinic after treatment.The patients were then divided into groups based on whether their HbeAg turned negative.The predictive ability of each indicator for HBeAg negative conversion was evaluated in the HBeAg negative group and the HBeAg positive group.Results:The results of logistic regression analysis suggested that pgRNA and HBcrAg were better indicators for predicting the clearance of HBeAg after treatment.Conclusion:For patients with chronic hepatitis B with low HBeAg levels,pgRNA is a good indicator in predicting HBeAg clearance during pegylated interferon therapy.

PEG-IFNα-2b联合替诺福韦治疗慢性乙型肝炎的疗效及对HBeAg转阴率、免疫功能的影响

目的:分析聚乙二醇干扰素α-2b(PEG-IFNα-2b)联合替诺福韦治疗慢性乙型肝炎的效果及对HBeAg转阴率、免疫功能的影响。方法:选取某院2019年3月—2022年3月收治的慢性乙型肝炎患者88例作为研究对象,依据随机抽签法分成研究组与对照组,每组44例。对照组接受替诺福韦治疗,研究组接受PEG-IFNα-2b联合替诺福韦治疗,比较2组HBeAg转阴率、HBsAg转阴率、治疗前后肝功能指标[谷氨酰转肽酶(GGT)、天门冬氨酸氨基转移酶(AST)、丙氨酸氨基转移酶(ALT)]、免疫功能指标(CD3^(+)、CD4^(+)/CD8^(+)、C3、C4)及血清炎性因子[视黄酸受体相关孤核受体(RORγt)、白细胞介素-17(IL-17)、IL-4]水平。结果:研究组HBeAg转阴率、HBsAg转阴率分别为45.45%、13.64%,高于对照组的11.36%、0,差异有统计学意义(P<0.05)。治疗后,研究组GGT、AST、ALT、IL-4、IL-17、RORγt分别为(30.42±5.39)U/L、(31.08±6.64)U/L、(29.37±4.68)U/L、(1.32±0.42)pg/mL、(0.64±0.19)pg/mL、(0.80±0.30),均低于对照组的(56.93±8.75)U/L、(38.72±5.83)U/L、(49.61±6.42)U/L、(3.91±1.14)pg/ml、(3.01±0.87)pg/ml、(1.61±0.36),差异有统计学意义(P<0.05)。研究组CD3^(+)、CD4^(+)/CD8^(+)、C3、C4分别为(66.81±8.55)%、(1.53±0.16)、(1.22±0.01)g/L、(0.42±0.07)g/L,均高于对照组的(61.03±8.49)%、(1.26±0.2)、(0.73±0.09)g/L、(0.22±0.06)g/L,差异有统计学意义(P<0.05)。结论:PEG-IFNα-2b联合替诺福韦治疗慢性乙型肝炎效果明显,可提高HBeAg、HBsAg转阴率,改善肝功能,增强免疫功能,抑制炎性反应。

PEG在头颈部肿瘤放疗患者中的应用及护理效果观察

评估PEG在头颈部肿瘤放疗患者中的应用及护理效果。方法 选取2022年6月-2023年6月在我院收治的头颈部肿瘤放疗患者120例,通过随机数字分配,将研究参与者分为两个组,每组包含60名参与者。对照组患者采用鼻胃管提供营养,观察组患者采用了经皮内胃造瘘术(PEG),比较两组体重指标、营养指标、并发症发生率和护理满意度。结果 两组营养指标(体重、红细胞、血红蛋白、血清白蛋白)差异不具有统计学意义(P>0.05);与对照组相比,观察组治疗后满意度显著升高(P<0.05)、并发症发生率显著降低(P<0.05)。结论 PEG的应用对于维持头颈部放疗患者的营养状态和生活质量具有显著的积极效果,能够降低患者并发症发生率,提高患者满意度。

低分子量PEG改性聚氨酯的合成及表征

随着经济的发展,人们对生活品质的要求越来越高,对穿着的要求更加苛刻,要求合成革提高防水透湿性能。采用不同分子量的PEG改性聚氨酯树脂,研究了PEG对合成革用湿法聚氨酯树脂的粘度、成肌性、剥离强度、耐水解等性能的影响,实验发现使用分子量1000的PEG,加入量占聚氨酯软段的5%时,树脂的综合性能最好,且软段的玻璃化转变温度Tg的降低11℃,高弹态区间向低温拓宽,同时水在改性后的聚氨酯皮膜上更容易铺展。

基于EVA和PEG估值法的半导体设备企业价值评估——以北方华创为例

随着全球半导体市场的繁荣发展,半导体设备需求正在不断增长,半导体设备行业也在迅速发展。鉴于该行业具有技术壁垒高、研发周期长、资金投入多、制造难度大、设备价值高等特点,论文围绕半导体设备行业的上述特点,将EVA估值法和PEG估值法相结合对企业价值进行评估,不仅可以为企业管理者提供决策建议,也能为市场投资者提供准确的投资方向。