The blue gum chalcid, Leptocybe invasa Fisher & La Salle, invaded China in 2007 and has subsequently caused substantial damage to eucalyptus trees. In the current paper, we investigated the susceptibility of 10 Eucal...The blue gum chalcid, Leptocybe invasa Fisher & La Salle, invaded China in 2007 and has subsequently caused substantial damage to eucalyptus trees. In the current paper, we investigated the susceptibility of 10 Eucalyptus spp. and Eucahetus dunnii to L. invasa in the field, determined the density of galls as well as the gall volume on these tree species, and monitored the population dynamics of wasps in Hainan and Guangdong provinces of China. The order of susceptibility to L. invasa was Eucalyptus urophyllaxEucalyptus camaldulensis〉E, urophylla (coppices)〉Eucalyptus exserta〉 Eucalyptus grandisxE, urophylla in Hainan, and Eucalyptus propinqua〉Eucalyptus saligna〉E, exserta〉Eucalyptus microcorys〉Eucahetus dunnii〉E, camaldulensis〉Eucalyptus tereticornis〉Eucalyptus robust in Guangdong, China. Although L. invasa generally damages the midribs and petioles of young leaves and the tender bark of twigs of eucalyptus, galls were not observed on leaves of E. microcorys, E. camaldulensis, or E. dunnii. Gall volume significantly differed among the tree species, and gall volume and wasp number were positively correlated. In Dongfang, Hainan Province, the overwintering period of L. invasa emergencing through the year was from the end of December to March of the next year, and the number of population was the greatest on E. urophylla^E, camaldulensis, and the smallest on E. grandis E. urophylla. In Guangzhou, Guangdong Province, L. invasa hardly emerged in winter from December to June of the next year, and the population was the greatest on E. propinqua, and the smallest on E. microcorys.展开更多
This paper deals with the photosynthetic properties of Eucalyptue camphoia. E. camaldulenaia. E. gunni-i. E. viminalia. E. giandia. E. dunii and E. maidenii. including the daily bariations of photosynthetic and respir...This paper deals with the photosynthetic properties of Eucalyptue camphoia. E. camaldulenaia. E. gunni-i. E. viminalia. E. giandia. E. dunii and E. maidenii. including the daily bariations of photosynthetic and respiratory rates, the comparison of the photosynthetic rates of various Eucalyriua spp. measured,the relationship between photo-synthetic rate and chlorophyll content, as well as the light saturation point.展开更多
The present study was carried out at Punjab Agricultural University,Ludhiana,India.Nineteen clones of Eucalyptus spp.were evaluated for tolerance to gall wasp.The total number of galls per plant were recorded at 1 mon...The present study was carried out at Punjab Agricultural University,Ludhiana,India.Nineteen clones of Eucalyptus spp.were evaluated for tolerance to gall wasp.The total number of galls per plant were recorded at 1 month after planting(MAP) and the number of galls per branch were recorded at 4 and 7 MAP.Gall wasp incidence(number of galls) was recorded on a whole plant basis during the seedling stage and the number of galls were recorded from the upper,middle and lower crown places at 4 and 7 MAP.Categorization was done on the basis of relative gall-wasp damage by keeping in view the total number of galls per plant and branch(leaves and petiole).No clone was found free from gall damage.Clones C-526,P-23 and P-103 were the least attacked by the gall wasp.Incidence as indicated by number of galls caused by Leptocybe invasa on eucalypts was higher in March than in December.展开更多
AIM: To investigate the presence and potency of natural enzyme inhibitors with hypoglycemic potentials amongst Eucalyptus Spp. by in vitro assays.METHODS: The leaf extracts of the three different Eucalyptus species [E...AIM: To investigate the presence and potency of natural enzyme inhibitors with hypoglycemic potentials amongst Eucalyptus Spp. by in vitro assays.METHODS: The leaf extracts of the three different Eucalyptus species [E. globulus(EG), E. citriodora(EC), E. camaldulensis(ECA)] were subjected to in vitro assay procedures to explore the prevalence of natural enzyme inhibitors(NEIs) after preliminary qualitative and quantitative phytochemical evaluations, to study their inhibitory actions against the enzymes like α-amylase, α-glucosidase, aldose reductase, angiotensin converting enzyme and dipeptidyl peptidase 4 playing pathogenic roles in type 2 diabetes. The antioxidant potential and total antioxidant capacity of the species were also evaluated.RESULTS: Major bioactive compounds like polyphenols(341.75 ± 3.63 to 496.85 ± 3.98) and flavonoids(4.89 ± 0.01 to 7.15 ± 0.02) were found in appreciable quantity in three species. Based on the IC50 values of the extracts under investigation, in all assays the effectivity was in the order of EG > ECA > EC. The results of the ferric reducing antioxidant power assay showed that the reducing ability of the species was also in the order of EG > ECA > EC. A strong correlation(R2 = 0.81-0.99) was found between the phenolic contents and the inhibitory potentials of the extracts against the targeted enzymes.CONCLUSION: These results show immense hypoglycemic potentiality of the Eucalyptus Spp. and a remarkable source of NEIs for a future phytotherapeutic approach in Type 2 diabetes.展开更多
Jute mallow is a nutritious leafy vegetable. The leaves are rich in proteins, vitamins and essential amino acids. Molecular characterization of Jute mallow with focus on improvement of leaf yield is scarcely reported....Jute mallow is a nutritious leafy vegetable. The leaves are rich in proteins, vitamins and essential amino acids. Molecular characterization of Jute mallow with focus on improvement of leaf yield is scarcely reported. In the present study, inter sequence simple repeats (ISSR) molecular markers were employed to assess genetic diversity and relationships of 83 accessions of Jute mallow from different parts of Africa and Asia conserved at the World Vegetable Center East and Southern Africa. A total of 89 bands were amplified by 8 ISSR primers. Number of polymorphic bands per primer ranged from 2 to 6 with an average of 2.75 bands per primer. Polymorphic information content (PIC) values ranged from 0.390 to 0.760 with average of 0.53. Average Nei’s gene diversity (h) and Shannon’s information index (I) were 0.335 and 0.494 respectively. The highest pairwise genetic distance was 0.431 observed in a population from East Africa accessions. PC1 and PC2 axis explained 21.69% and 11.66% of the total variation respectively. UPGMA cluster analysis grouped the accessions into six main clusters at genetic similarity coefficient of 0.53 as standard value for classification. These results have important implications for jute mallow breeding and conservation.展开更多
Bio-jarosite,an iron mineral synthesized biologically using bacteria,is a substitute for iron catalysts in the Fenton oxidation of organic pollutants.Iron nanocatalysts have been widely used as Fenton catalysts becaus...Bio-jarosite,an iron mineral synthesized biologically using bacteria,is a substitute for iron catalysts in the Fenton oxidation of organic pollutants.Iron nanocatalysts have been widely used as Fenton catalysts because they have a larger surface area than ordinary catalysts,are highly recyclable,and can be treated efficiently.This study aimed to explore the catalytic properties of bio-jarosite iron nanoparticles syn-thesized with green methods using two distinct plant species:Azadirachta indica and Eucalyptus gunni.The focus was on the degradation of dicamba via Fenton oxidation.The synthesized nanoparticles exhibited different particle size,shape,surface area,and chemical composition characteristics.Both particles were effective in removing dicamba,with removal efficiencies of 96.8%for A.indica bio-jarosite iron nano-particles(ABFeNPs)and 93.0%for E.gunni bio-jarosite iron nanoparticles(EBFeNPs)within 120 min of treatment.Increasing the catalyst dosage by 0.1 g/L resulted in 7.6%and 43.0%increases in the dicamba removal efficiency for EBFeNPs and ABFeNPs with rate constants of 0.025 min^(-1) and 0.023 min^(-1),respectively,confrming their catalytic roles.Additionally,the high efficiency of both catalysts was demonstrated through five consecutive cycles of linear pseudo-first-order Fenton oxidation reactions.展开更多
Strawberry (Fragaria spp.) is one of the most important fruits classified as exotic fruits imported into Cameroon. To have an inventory of its cultivation in Cameroon, a survey study was carried out among eight farms ...Strawberry (Fragaria spp.) is one of the most important fruits classified as exotic fruits imported into Cameroon. To have an inventory of its cultivation in Cameroon, a survey study was carried out among eight farms of Fragaria spp. from January 2021 to February 2022. The plant was introduced in Cameroon in 2018. There are 13 varieties of Fragaria spp. currently cultivated. Among these 13 varieties, eleven are hybrids of Fragaria x ananassa (“Amiga”, “Amine”, “Camarosa”, “Chandler”, “Charlotte”, “Elsanta”, “Gariguette”, “Madame Moutot”, “Ostara”, “Ruby gem” and “San Andreas”), and two of the hybrids of Fragaria vesca (“Maestro” and “Mara des bois”). The cropping system, irrigation system, and type of fertilizers applied differ from one strawberry farm to another. Biofertilizers (such as mycorrhizal), inorganic and organic fertilizers are actually used to improve production. The potential annual production of strawberries from January 2021 to February 2022, estimated based on the survey data, was 21.216 tons for all growers. Among these eight production farms, the Lolodorf BIO Farm presents 6000 kg (six tons) of strawberries and 100,000 stolons (seedlings) produced, from seven varieties of Fragaria spp. cultivated, with 6 varieties which are hybrids variety Fragaria x ananassa (“Amiga”, “Amine”, “Chandler”, “Gariguette”, “Madame Moutot”, and “Ruby gem”), and one which is a hybrid of Fragaria vesca (“Mara des bois”). Certain diseases were also observed and recorded depending on the growing areas.展开更多
Resistant bacteria can be transmitted to humans through feces or contaminated meat from local chickens. Bacterial strains were isolated from the intestinal contents of 400 local chicken samples from various sales site...Resistant bacteria can be transmitted to humans through feces or contaminated meat from local chickens. Bacterial strains were isolated from the intestinal contents of 400 local chicken samples from various sales sites. These strains were then characterized using bacteriological and biochemical methods to identify resistant strains. In a study conducted in Ouagadougou, we systematically collected chicken fecal samples from 20 locations across the city, followed by isolation and identification of Salmonella spp. using specific enrichment and culture methods, as well as Escherichia coli. Bacterial strains were characterized using antibiotic resistance profiles were determined through agar diffusion tests, revealing sensitivity or resistance to a range of antibiotics based on established scientific criteria. The results showed that out of the 400 samples collected, 81.25% and 63.5% were contaminated by Escherichia coli and Salmonella spp., respectively. Among these, 86.15% of identified Escherichia coli and 50.78% of Salmonella spp. displayed resistance to at least one tested antibiotic. Among 280 Escherichia coli isolates identified resistant to at least one antibiotic, 31.07% were resistant to cefotaxime (CTX), 20.35% to ceftazidime (CAZ), 21.07% to ceftriaxone (CTR), 75% to amoxicillin clavulanic acid (AMC), 23.57% aztreoname (ATM) and 27.14% were resistant to imipenem (IMP). In the case of the 129 Salmonella spp. isolates resistant to at least one tested antibiotic, 34.88% were resistant to CTX;41.08% to CAZ;35.65% to CTR, 92% to AMC, 39.53% to ATM and finally 47.28% were resistant to IMP. Our study revealed high prevalence of resistance in bacterial strains isolated from local chickens sold outdoors in Ouagadougou. These findings raise significant public health concerns, due to the possible transmission of these resistant strains to humans through the consumption of contaminated meat, thus complicating the treatment of bacterial infections.展开更多
Hemicellulose and lignin are not reasonably utilized during the dissolved pulp preparation process.This work aimed to propose a process for the co-production of dissolving pulp,furfural,and lignin from eucalyptus.High...Hemicellulose and lignin are not reasonably utilized during the dissolved pulp preparation process.This work aimed to propose a process for the co-production of dissolving pulp,furfural,and lignin from eucalyptus.High-grade dissolving pulp was prepared from eucalyptus using a combination of extremely low acid(ELA)pretreatment,Kraft cooking,and elementary chlorine-free(ECF)bleaching.The obtained pre-hydrolysate was catalytic conversion into furfural in a biphasic system,and lignin during Kraft cooking and ECF was recovered.The process condition was discussed as well as the mass flow direction.The results showed that ELA pretreatment could effectively remove 80.1%hemicellulose.Compared with traditional hydrothermal pretreatment,the ELA pretreatment significantly increased the xylose yield from 5.05 to 14.18 g/L at 170℃ for 2 h,which had practical significance for furfural production.The 82.7%furfural yield and 82.9%furfural selectivity were obtained from xylose-rich pre-hydrolysate using NaCl as a phase modifier in a biphasic system with 4-methyl-2-pentanone(MIBK)as an organic phase by ion exchange resin catalysts at 190℃ for 2 h.Subsequently,the pretreated eucalyptus was subjected to Kraft cooking,and the optimal alkali amount was 14%.Then,the Kraft pulp was bleached using the O-D1-EP-D_(2) sequence,and dissolving pulp was obtained with an ISO brightness of 86.0%,viscosity of 463 mL/g,andα-cellulose content of 95.4%.The Kraft lignin which has a potential application was investigated by 2D-HSQC NMR and 31P NMR.The results showed that the S/G ratio of Kraft lignin was 1.93,and the content of phenolic hydroxyl groups was 2.53 mmol/g.Moreover,based on the above proposed process,30.5 g dissolving pulp,5.5 g furfural,and 21.2 g lignin per 100 g eucalyptus chips(oven dry)were produced.This research will provide new catalysis and pulping technical routes for dissolving pulp,furfural,and Kraft lignin products,which are in great demand in the chemical industry.展开更多
伪距单点定位(Pseudo-range Single Point Positioning,SPP)应用较早且广泛。随着GNSS相关技术的不断进步,伪距观测值与广播星历的精度也在不断提高,多GNSS系统还带来了更多的伪距观测值,SPP依然值得关注。RTKLIB作为一款广为接受的多功...伪距单点定位(Pseudo-range Single Point Positioning,SPP)应用较早且广泛。随着GNSS相关技术的不断进步,伪距观测值与广播星历的精度也在不断提高,多GNSS系统还带来了更多的伪距观测值,SPP依然值得关注。RTKLIB作为一款广为接受的多功能GNSS数据处理开源软件,是实现二次开发的良好平台,为此,本文对新版本RTKLIB(b34)SPP数据处理进行了解析,给出了其处理流程,分析了其平差求解、结果检验、异常检测的原理,指出了其优缺点,为今后借鉴或改进提供了参考。展开更多
基金supported by the Forest Special Fund of Guangdong Province for Technological Innovation Project, China(2010KJCX015-01)
文摘The blue gum chalcid, Leptocybe invasa Fisher & La Salle, invaded China in 2007 and has subsequently caused substantial damage to eucalyptus trees. In the current paper, we investigated the susceptibility of 10 Eucalyptus spp. and Eucahetus dunnii to L. invasa in the field, determined the density of galls as well as the gall volume on these tree species, and monitored the population dynamics of wasps in Hainan and Guangdong provinces of China. The order of susceptibility to L. invasa was Eucalyptus urophyllaxEucalyptus camaldulensis〉E, urophylla (coppices)〉Eucalyptus exserta〉 Eucalyptus grandisxE, urophylla in Hainan, and Eucalyptus propinqua〉Eucalyptus saligna〉E, exserta〉Eucalyptus microcorys〉Eucahetus dunnii〉E, camaldulensis〉Eucalyptus tereticornis〉Eucalyptus robust in Guangdong, China. Although L. invasa generally damages the midribs and petioles of young leaves and the tender bark of twigs of eucalyptus, galls were not observed on leaves of E. microcorys, E. camaldulensis, or E. dunnii. Gall volume significantly differed among the tree species, and gall volume and wasp number were positively correlated. In Dongfang, Hainan Province, the overwintering period of L. invasa emergencing through the year was from the end of December to March of the next year, and the number of population was the greatest on E. urophylla^E, camaldulensis, and the smallest on E. grandis E. urophylla. In Guangzhou, Guangdong Province, L. invasa hardly emerged in winter from December to June of the next year, and the population was the greatest on E. propinqua, and the smallest on E. microcorys.
基金Subsist by the National Natural Science foundation of China
文摘This paper deals with the photosynthetic properties of Eucalyptue camphoia. E. camaldulenaia. E. gunni-i. E. viminalia. E. giandia. E. dunii and E. maidenii. including the daily bariations of photosynthetic and respiratory rates, the comparison of the photosynthetic rates of various Eucalyriua spp. measured,the relationship between photo-synthetic rate and chlorophyll content, as well as the light saturation point.
文摘The present study was carried out at Punjab Agricultural University,Ludhiana,India.Nineteen clones of Eucalyptus spp.were evaluated for tolerance to gall wasp.The total number of galls per plant were recorded at 1 month after planting(MAP) and the number of galls per branch were recorded at 4 and 7 MAP.Gall wasp incidence(number of galls) was recorded on a whole plant basis during the seedling stage and the number of galls were recorded from the upper,middle and lower crown places at 4 and 7 MAP.Categorization was done on the basis of relative gall-wasp damage by keeping in view the total number of galls per plant and branch(leaves and petiole).No clone was found free from gall damage.Clones C-526,P-23 and P-103 were the least attacked by the gall wasp.Incidence as indicated by number of galls caused by Leptocybe invasa on eucalypts was higher in March than in December.
文摘AIM: To investigate the presence and potency of natural enzyme inhibitors with hypoglycemic potentials amongst Eucalyptus Spp. by in vitro assays.METHODS: The leaf extracts of the three different Eucalyptus species [E. globulus(EG), E. citriodora(EC), E. camaldulensis(ECA)] were subjected to in vitro assay procedures to explore the prevalence of natural enzyme inhibitors(NEIs) after preliminary qualitative and quantitative phytochemical evaluations, to study their inhibitory actions against the enzymes like α-amylase, α-glucosidase, aldose reductase, angiotensin converting enzyme and dipeptidyl peptidase 4 playing pathogenic roles in type 2 diabetes. The antioxidant potential and total antioxidant capacity of the species were also evaluated.RESULTS: Major bioactive compounds like polyphenols(341.75 ± 3.63 to 496.85 ± 3.98) and flavonoids(4.89 ± 0.01 to 7.15 ± 0.02) were found in appreciable quantity in three species. Based on the IC50 values of the extracts under investigation, in all assays the effectivity was in the order of EG > ECA > EC. The results of the ferric reducing antioxidant power assay showed that the reducing ability of the species was also in the order of EG > ECA > EC. A strong correlation(R2 = 0.81-0.99) was found between the phenolic contents and the inhibitory potentials of the extracts against the targeted enzymes.CONCLUSION: These results show immense hypoglycemic potentiality of the Eucalyptus Spp. and a remarkable source of NEIs for a future phytotherapeutic approach in Type 2 diabetes.
文摘Jute mallow is a nutritious leafy vegetable. The leaves are rich in proteins, vitamins and essential amino acids. Molecular characterization of Jute mallow with focus on improvement of leaf yield is scarcely reported. In the present study, inter sequence simple repeats (ISSR) molecular markers were employed to assess genetic diversity and relationships of 83 accessions of Jute mallow from different parts of Africa and Asia conserved at the World Vegetable Center East and Southern Africa. A total of 89 bands were amplified by 8 ISSR primers. Number of polymorphic bands per primer ranged from 2 to 6 with an average of 2.75 bands per primer. Polymorphic information content (PIC) values ranged from 0.390 to 0.760 with average of 0.53. Average Nei’s gene diversity (h) and Shannon’s information index (I) were 0.335 and 0.494 respectively. The highest pairwise genetic distance was 0.431 observed in a population from East Africa accessions. PC1 and PC2 axis explained 21.69% and 11.66% of the total variation respectively. UPGMA cluster analysis grouped the accessions into six main clusters at genetic similarity coefficient of 0.53 as standard value for classification. These results have important implications for jute mallow breeding and conservation.
文摘Bio-jarosite,an iron mineral synthesized biologically using bacteria,is a substitute for iron catalysts in the Fenton oxidation of organic pollutants.Iron nanocatalysts have been widely used as Fenton catalysts because they have a larger surface area than ordinary catalysts,are highly recyclable,and can be treated efficiently.This study aimed to explore the catalytic properties of bio-jarosite iron nanoparticles syn-thesized with green methods using two distinct plant species:Azadirachta indica and Eucalyptus gunni.The focus was on the degradation of dicamba via Fenton oxidation.The synthesized nanoparticles exhibited different particle size,shape,surface area,and chemical composition characteristics.Both particles were effective in removing dicamba,with removal efficiencies of 96.8%for A.indica bio-jarosite iron nano-particles(ABFeNPs)and 93.0%for E.gunni bio-jarosite iron nanoparticles(EBFeNPs)within 120 min of treatment.Increasing the catalyst dosage by 0.1 g/L resulted in 7.6%and 43.0%increases in the dicamba removal efficiency for EBFeNPs and ABFeNPs with rate constants of 0.025 min^(-1) and 0.023 min^(-1),respectively,confrming their catalytic roles.Additionally,the high efficiency of both catalysts was demonstrated through five consecutive cycles of linear pseudo-first-order Fenton oxidation reactions.
文摘Strawberry (Fragaria spp.) is one of the most important fruits classified as exotic fruits imported into Cameroon. To have an inventory of its cultivation in Cameroon, a survey study was carried out among eight farms of Fragaria spp. from January 2021 to February 2022. The plant was introduced in Cameroon in 2018. There are 13 varieties of Fragaria spp. currently cultivated. Among these 13 varieties, eleven are hybrids of Fragaria x ananassa (“Amiga”, “Amine”, “Camarosa”, “Chandler”, “Charlotte”, “Elsanta”, “Gariguette”, “Madame Moutot”, “Ostara”, “Ruby gem” and “San Andreas”), and two of the hybrids of Fragaria vesca (“Maestro” and “Mara des bois”). The cropping system, irrigation system, and type of fertilizers applied differ from one strawberry farm to another. Biofertilizers (such as mycorrhizal), inorganic and organic fertilizers are actually used to improve production. The potential annual production of strawberries from January 2021 to February 2022, estimated based on the survey data, was 21.216 tons for all growers. Among these eight production farms, the Lolodorf BIO Farm presents 6000 kg (six tons) of strawberries and 100,000 stolons (seedlings) produced, from seven varieties of Fragaria spp. cultivated, with 6 varieties which are hybrids variety Fragaria x ananassa (“Amiga”, “Amine”, “Chandler”, “Gariguette”, “Madame Moutot”, and “Ruby gem”), and one which is a hybrid of Fragaria vesca (“Mara des bois”). Certain diseases were also observed and recorded depending on the growing areas.
文摘Resistant bacteria can be transmitted to humans through feces or contaminated meat from local chickens. Bacterial strains were isolated from the intestinal contents of 400 local chicken samples from various sales sites. These strains were then characterized using bacteriological and biochemical methods to identify resistant strains. In a study conducted in Ouagadougou, we systematically collected chicken fecal samples from 20 locations across the city, followed by isolation and identification of Salmonella spp. using specific enrichment and culture methods, as well as Escherichia coli. Bacterial strains were characterized using antibiotic resistance profiles were determined through agar diffusion tests, revealing sensitivity or resistance to a range of antibiotics based on established scientific criteria. The results showed that out of the 400 samples collected, 81.25% and 63.5% were contaminated by Escherichia coli and Salmonella spp., respectively. Among these, 86.15% of identified Escherichia coli and 50.78% of Salmonella spp. displayed resistance to at least one tested antibiotic. Among 280 Escherichia coli isolates identified resistant to at least one antibiotic, 31.07% were resistant to cefotaxime (CTX), 20.35% to ceftazidime (CAZ), 21.07% to ceftriaxone (CTR), 75% to amoxicillin clavulanic acid (AMC), 23.57% aztreoname (ATM) and 27.14% were resistant to imipenem (IMP). In the case of the 129 Salmonella spp. isolates resistant to at least one tested antibiotic, 34.88% were resistant to CTX;41.08% to CAZ;35.65% to CTR, 92% to AMC, 39.53% to ATM and finally 47.28% were resistant to IMP. Our study revealed high prevalence of resistance in bacterial strains isolated from local chickens sold outdoors in Ouagadougou. These findings raise significant public health concerns, due to the possible transmission of these resistant strains to humans through the consumption of contaminated meat, thus complicating the treatment of bacterial infections.
基金This research was funded by the National Natural Science Foundation of China(No.21978104)the Program for the National Key Research and Development Program of China(No.2021YFC2101601).
文摘Hemicellulose and lignin are not reasonably utilized during the dissolved pulp preparation process.This work aimed to propose a process for the co-production of dissolving pulp,furfural,and lignin from eucalyptus.High-grade dissolving pulp was prepared from eucalyptus using a combination of extremely low acid(ELA)pretreatment,Kraft cooking,and elementary chlorine-free(ECF)bleaching.The obtained pre-hydrolysate was catalytic conversion into furfural in a biphasic system,and lignin during Kraft cooking and ECF was recovered.The process condition was discussed as well as the mass flow direction.The results showed that ELA pretreatment could effectively remove 80.1%hemicellulose.Compared with traditional hydrothermal pretreatment,the ELA pretreatment significantly increased the xylose yield from 5.05 to 14.18 g/L at 170℃ for 2 h,which had practical significance for furfural production.The 82.7%furfural yield and 82.9%furfural selectivity were obtained from xylose-rich pre-hydrolysate using NaCl as a phase modifier in a biphasic system with 4-methyl-2-pentanone(MIBK)as an organic phase by ion exchange resin catalysts at 190℃ for 2 h.Subsequently,the pretreated eucalyptus was subjected to Kraft cooking,and the optimal alkali amount was 14%.Then,the Kraft pulp was bleached using the O-D1-EP-D_(2) sequence,and dissolving pulp was obtained with an ISO brightness of 86.0%,viscosity of 463 mL/g,andα-cellulose content of 95.4%.The Kraft lignin which has a potential application was investigated by 2D-HSQC NMR and 31P NMR.The results showed that the S/G ratio of Kraft lignin was 1.93,and the content of phenolic hydroxyl groups was 2.53 mmol/g.Moreover,based on the above proposed process,30.5 g dissolving pulp,5.5 g furfural,and 21.2 g lignin per 100 g eucalyptus chips(oven dry)were produced.This research will provide new catalysis and pulping technical routes for dissolving pulp,furfural,and Kraft lignin products,which are in great demand in the chemical industry.
文摘伪距单点定位(Pseudo-range Single Point Positioning,SPP)应用较早且广泛。随着GNSS相关技术的不断进步,伪距观测值与广播星历的精度也在不断提高,多GNSS系统还带来了更多的伪距观测值,SPP依然值得关注。RTKLIB作为一款广为接受的多功能GNSS数据处理开源软件,是实现二次开发的良好平台,为此,本文对新版本RTKLIB(b34)SPP数据处理进行了解析,给出了其处理流程,分析了其平差求解、结果检验、异常检测的原理,指出了其优缺点,为今后借鉴或改进提供了参考。