BACKGROUND:Patients with diabetes mellitus(DM)are vulnerable to community-acquired pneumonia(CAP),which have a high mortality rate.We aimed to investigate the value of heparin-binding protein(HBP)as a prognostic marke...BACKGROUND:Patients with diabetes mellitus(DM)are vulnerable to community-acquired pneumonia(CAP),which have a high mortality rate.We aimed to investigate the value of heparin-binding protein(HBP)as a prognostic marker of mortality in patients with DM and CAP.METHODS:This retrospective study included CAP patients who were tested for HBP at intensive care unit(ICU)admission from January 2019 to April 2020.Patients were allocated to the DM or non-DM group and paired with propensity score matching.Baseline characteristics and clinical outcomes up to 90 days were evaluated.The primary outcome was the 10-day mortality.Receiver operating characteristic(ROC)curves,Kaplan-Meier analysis,and Cox regression were used for statistical analysis.RESULTS:Among 152 enrolled patients,60 pairs were successfully matched.There was no significant difference in 10-day mortality,while more patients in the DM group died within 28 d(P=0.024)and 90 d(P=0.008).In the DM group,HBP levels at ICU admission were higher in 10-day non-survivors than in 10-day survivors(median 182.21[IQR:55.43-300]ng/ml vs.median 66.40[IQR:34.13-107.85]ng/mL,P=0.019),and HBP levels could predict the 10-day mortality with an area under the ROC curve of 0.747.The cut-off value,sensitivity,and specificity were 160.6 ng/mL,66.7%,and 90.2%,respectively.Multivariate Cox regression analysis indicated that HBP was an independent prognostic factor for 10-day(HR 7.196,95%CI:1.596-32.455,P=0.01),28-day(HR 4.381,95%CI:1.449-13.245,P=0.009),and 90-day mortality(HR 4.581,95%CI:1.637-12.819,P=0.004)in patients with DM.CONCLUSION:Plasma HBP at ICU admission was associated with the 10-day,28-day,and 90-day mortality,and might be a prognostic factor in patients with DM and CAP.展开更多
Colorectal cancer has a high incidence and mortality rate in China, with the majority of cases being middle and low rectal cancer. Surgical intervention is currently the main treatment modality for locally advanced re...Colorectal cancer has a high incidence and mortality rate in China, with the majority of cases being middle and low rectal cancer. Surgical intervention is currently the main treatment modality for locally advanced rectal cancer, with the common goal of improving oncological outcomes while preserving function. The controversy regarding the circumferential resection margin distance in rectal cancer surgery has been resolved. With the promotion of neoadjuvant therapy concepts and advancements in technology, treatment strategies have become more diverse.Following tumor downstaging, there is an increasing trend towards extending the safe distance of distal rectal margin. This provides more opportunities for patients with low rectal cancer to preserve their anal function.However, there is currently no consensus on the specific distance of distal resection margin.展开更多
The build-up of misfoldedα-synuclein(α-syn)in the central nervous system is the pathological hallmark of a number of neurodegenerative diseases that are known asα-synucleinopathies.These include Parkinson’s diseas...The build-up of misfoldedα-synuclein(α-syn)in the central nervous system is the pathological hallmark of a number of neurodegenerative diseases that are known asα-synucleinopathies.These include Parkinson’s disease(PD),Parkinson’s disease with dementia(PDD),dementia with Lewy body(LB),multiple system atrophy(MSA),and a subset of Alzheimer’s disease.Growing evidence underscores that the intercellular transmission and amplification of pathologicalα-syn are critical processes underlying the progression ofα-synucleinopathies(Peng et al.,2020),and as such,the study of these processes could lead to the identification of promising therapeutics to mitigate disease progression.Most previous studies have focused solely on pathological seeds in relation to disease progression.展开更多
Cu-Fe composite oxides were prepared by co-precipitation method and tested for higher alcohol synthesis from syngas. The selectivity to C2+OH and C6+OH in alcohol distribution was very high while the methane product...Cu-Fe composite oxides were prepared by co-precipitation method and tested for higher alcohol synthesis from syngas. The selectivity to C2+OH and C6+OH in alcohol distribution was very high while the methane product fraction in hydrocarbon distribution was rather low, demonstrating a promising potential in higher alcohols synthesis from syngas. The distribution of alcohols and hydrocarbons approximately obeyed Anderson-Schulz-Flory distribution with similar chain growth probability, indicating alcohols and hydrocarbons derived from the same intermediates. The effects of Cu/Fe molar ratio, reaction temperature and gas hourly space velocity (GHSV) on catalytic performance were studied in detail. The sample with a Cu/Fe molar ratio of 10/1 exhibited the best catalytic performance. Higher reaction temperature accelerated water-gas-shift reaction and led to lower total alcohols selectivity. GHSV showed great effect on catalytic performance and higher GHSV increased the total alcohol selectivity, indicating there existed visible dehydration reaction of alcohol into hydrocarbon.展开更多
The directly selective hydrogenolysis of xylitol to ethylene glycol(EG) and 1,2-propylene glycol(1,2-PDO)was performed on Cu–Ni–ZrO_2 catalysts prepared by a co-precipitation method. Upon optimizing the reaction con...The directly selective hydrogenolysis of xylitol to ethylene glycol(EG) and 1,2-propylene glycol(1,2-PDO)was performed on Cu–Ni–ZrO_2 catalysts prepared by a co-precipitation method. Upon optimizing the reaction conditions(518 K, 4.0 MPaH_2 and 3 h), 97.0% conversion of xylitol and 63.1% yield of glycols were obtained in water without extra inorganic base. The catalyst still remained stable activity after six cycles and above 80% total selectivity of glycols was obtained when using 20.0% xylitol concentration. XRD, TEM and ICP results indicated that Cu–Ni–ZrO_2 catalysts possess favorable stability. Cu and Ni are beneficial to the cleavage of C–O and C–H bond, respectively. To reduce the hydrogen consumption, isopropanol was added as in-situ hydrogen source and 96.4% conversion of xylitol with 43.6% yield of glycols were realized.展开更多
The X-ray photoelectron spectroscopy (XPS) was used to investigate the surface characteristic of potassium-promoted or un-promoted both β-Mo2C and α-MoC1-x pretreated by syngas at different temperatures,and the pr...The X-ray photoelectron spectroscopy (XPS) was used to investigate the surface characteristic of potassium-promoted or un-promoted both β-Mo2C and α-MoC1-x pretreated by syngas at different temperatures,and the promotional effect of potassium on the catalytic performance was also studied.XPS results revealed that the content of surface Mo and its valence distribution between β-Mo2C and α-MoC1-x were quite different.Promoted by potassium,the remarkable changes were observed for surface composition and valence of Mo distribution over β-Mo2C.Potassium had strong electronic effect on β-Mo2C,which led to a higher Mo4+ content.On the contrary,potassium had little electronic effect on α-MoC1-x,and K-Mo interaction was weak.Therefore,Mo0 and Mo2+ became the dominant species on the catalyst surface,and the Mo4+ content showed almost no increase as the pretreatment temperature enhanced.In terms of catalytic performance of molybdenum carbides,the increase in Mo0 most likely explained the increase in hydrocarbon selectivity,yet Mo4+ might be responsible for the alcohols synthesis.展开更多
Nickel and potassium co-modified β-Mo2C catalysts were prepared and used for CO hydrogenation reaction. The major products over β-Mo2C were C1-C4 hydrocarbons, only few alcohols were obtained. Addition of potassium ...Nickel and potassium co-modified β-Mo2C catalysts were prepared and used for CO hydrogenation reaction. The major products over β-Mo2C were C1-C4 hydrocarbons, only few alcohols were obtained. Addition of potassium resulted in remarkable selectivity shift from hydrocarbons to alcohols at the expense of CO conversion over β-Mo2C. Moreover, it was found that potassium enhanced the ability of chain propagation with a higher C2+OH production. Modified by nickel,β-Mo2C showed a relatively high CO conversion, however, the products were similar to those of pure β-Mo2C. When co-modified by nickel and potassium,β-Mo2C exhibited high activity and selectivity towards mixed alcohols synthesis, and also the whole chain propagation to produce alcohols especially for the stage of C1 OH to C2OH was remarkably enhanced. It was concluded that the Ni and K had, to some extent, synergistic effect on CO conversion.展开更多
MnOx-promoted Ni-based catalyst supported by ZnO was developed to selectively hydrogenate glucose into polyols in water at 523 K with a yield of 64.9%. Using glucose, sorbitol, glycerol and LA as the rawmaterials, the...MnOx-promoted Ni-based catalyst supported by ZnO was developed to selectively hydrogenate glucose into polyols in water at 523 K with a yield of 64.9%. Using glucose, sorbitol, glycerol and LA as the rawmaterials, the roles of nickel, ZnO and MnOx were investigated. The results show that nickel provided a new pathway of glucose to sorbitol and played an important role in the hydrogenation of C3 intermediates to 1,2-propanediol(1,2-PDO). The high yield of 1, 2-PDO was attributed to effective C–C bond cleavage performance of ZnO support promoted by MnOx. ZnO and MnOx contribute to the conversion of glycerol to lactic acid(LA) and LA to 1, 2-PDO, respectively. A concise pathway for hydrogenation of glucose over Ni-based catalyst was proposed.展开更多
Chinese fir(Cunninghamia lanceolata(Lamb.)Hook),a fast-growing and economically important timber tree species in China,is widely used in construction,furniture,and paper manufacture but has a long breeding cycle.Chemi...Chinese fir(Cunninghamia lanceolata(Lamb.)Hook),a fast-growing and economically important timber tree species in China,is widely used in construction,furniture,and paper manufacture but has a long breeding cycle.Chemical mutagens,such as ethyl methane sulfonate(EMS)and sodium azide(SA),are widely used in crops such as rice,wheat,cotton,soybean and sugarcane but their utility for tree breeding is unknown.In this study we examined the effects of EMS and S A on Chinese fir seed germination and growth.Chinese fir seeds were treated with the two chemical mutagens;were planted in Jiangle County,Fujian Province,China;and their heights were measured from 2011 to2017.The concentrations and durations of treatment with the two chemical mutagens were significantly associated with the Chinese fir seedling and mortality rates,as well as with the heights of trees from the seedling stage to 3 years old.We also generated 127 mutants with abnormal branches and reproductive growth.We report here the effects of two chemical mutagens on Chinese fir breeding;our data will contribute to knowledge of the utility of EMS and SA in forestry.展开更多
Based on the difference of hydroxy group configuration on the special adsorption and coordination of phosphate on the dispersed α-Fe2O3 nanodisks with diameter of 150-200 nm different planes of α-Fe2O3 nanoparticles...Based on the difference of hydroxy group configuration on the special adsorption and coordination of phosphate on the dispersed α-Fe2O3 nanodisks with diameter of 150-200 nm different planes of α-Fe2O3 nanoparticles, using (001) plane of α-Fe2O3, well-crystallized and well and thickness of 40-80 nm were synthesized via a hydrotherrnal method. The magnetic properties of synthesized nanodisks were investigated. It was found that the nanodisks possessed a saturation magnetization (Ms) of 0.38 emu/g, a rernanent magnetization (Mr) of 0.031 ernu/g and a coercivity of 452.91 Oe at room temperature. The Mr and coercivity of synthesized α-Fe2O3 nanodisks are higher and the Ms is lower than those of other previously reported α-Fe2O3 nanostructures.展开更多
Fe modified and un-modified K/Mo2C were prepared and investigated as catalysts for CO hydrogenation reaction. Compared with K/Mo2C catalyst, the addition of Fe increased the production of alcohols, especially the C2+...Fe modified and un-modified K/Mo2C were prepared and investigated as catalysts for CO hydrogenation reaction. Compared with K/Mo2C catalyst, the addition of Fe increased the production of alcohols, especially the C2+OH. Meanwhile, considerable amounts of C5+ hydrocar- bons and C2= -C4= were formed, whereas methane selectivity greatly decreased. Also, the activity and selectivity of the catalyst were readily affected by the reaction pressure and temperature employed. According to the XPS results, Mo4+ might be responsible for the production of alcohols, whereas the low valence state of Mo species such as Mo^0 and/or Mo^2+ might be account for the high activity and selectivity toward hydrocarbons.展开更多
Highly dispersed Cu-base catalyst has been prepared via thermal decomposition of layered double hydroxides precursors. The XRD pattern and the HRTEM images of the as prepared catalyst confirmed the high dispersion of ...Highly dispersed Cu-base catalyst has been prepared via thermal decomposition of layered double hydroxides precursors. The XRD pattern and the HRTEM images of the as prepared catalyst confirmed the high dispersion of Cu and Fe ions. Results show that the catalyst has a relatively high selectivity of alkanes at low temperature.展开更多
Robinia pseudoacacia is an important afforesta-tion tree introduced to China in 1878.In the present study,we examined the genetic diversity among 687 strains rep-resenting four improved varieties and two secondary pro...Robinia pseudoacacia is an important afforesta-tion tree introduced to China in 1878.In the present study,we examined the genetic diversity among 687 strains rep-resenting four improved varieties and two secondary prov-enances,comprising 641 clones and 46 seedlings.Ninety-one simple sequence repeats(SSRs)were selected through segregation analysis and polymorphism characterization,and all sampled individuals were genotyped using well-characterized SSR markers.After excluding loci with non-neutral equilibrium,missing locus data and null alleles,we used 36 primer pairs to assess the genetic diversity of these germplasm resources,revealing vast genetic differentiation among the samples,with an average of 8.352 alleles per locus and a mean Shannon′s index of 1.302.At the popula-tion level,the partitioning of variability was assessed using analysis of molecular variance,which revealed 93%and 7%variation within and among collection sites,respectively.Four clusters were detected using structure analysis,indi-cating a degree of genetic differentiation among the six populations.Insights into the genetic diversity and structure of R.pseudoacacia provide a theoretical basis for the con-servation,breeding and sustainable development in China.展开更多
To gain deep insight into the Morphological effect of NixMg1-xO catalysts on the reaction of CO2reforming with methane, we designed and fabricated three different spatial structural NixMg1-xO catalysts.These NixMg1-xO...To gain deep insight into the Morphological effect of NixMg1-xO catalysts on the reaction of CO2reforming with methane, we designed and fabricated three different spatial structural NixMg1-xO catalysts.These NixMg1-xO catalysts with specific models such as rod, sheet and sphere, exhibited various activity and stability in CO2reforming reaction. Herein NixMg1-xO nanorods displayed higher catalytic activity, in which methane conversion was up to 72% and CO2conversion was 64% at 670°C with a space velocity of 79,200 mL/(gcath), compared with nanosheet and nanosphere counterparts. Furthermore, both catalysts of NixMg1-xO nanorod and nanosheet showed a high resistance toward coke deposition and sintering of active sites in the process of CO2reforming of methane.展开更多
CO_(2)hydrogenation to value-added chemicals is a promising pathway to solve CO_(2)-relevant environmental problems but still remains a great challenge.Herein,we report a CeO_(2)nanostructure supported Rh single atoms...CO_(2)hydrogenation to value-added chemicals is a promising pathway to solve CO_(2)-relevant environmental problems but still remains a great challenge.Herein,we report a CeO_(2)nanostructure supported Rh single atoms(Rh-SAs/CeO_(2))catalyst and was used for the efficient CO_(2)hydrogenation to HCOOH.The Rh-SAs/CeO_(2)exhibited high catalytic activity with turnover numbers(TON)up to 221 at 200℃,which was 4-fold to that of CeO_(2)supported Rh nanoparticles(Rh-NPs/CeO_(2)).Moreover,HCOOH selectivity for Rh-SAs/CeO_(2)reached 85%,much higher than that of Rh-NPs/CeO_(2)(46%).Mechanism studies revealed that Rh single atoms in the Rh-SAs/CeO_(2)with high metal atoms utilization efficiency not only provided abundant active sites to promote the catalytic activity,but also suppressed the decomposition of HCOOH to CO and benefited the formation of HCOOH.展开更多
A novel synthesis route to obtain highly dispersed molybdenum carbides in porous silica is described. The synthesis was carried out by a single-step heat treatment of molybdenum-containing and methyl-modified silica ...A novel synthesis route to obtain highly dispersed molybdenum carbides in porous silica is described. The synthesis was carried out by a single-step heat treatment of molybdenum-containing and methyl-modified silica (Mo-M-SiO2) in argon atmosphere at 973 K. Mo-M-SiO2 precursor was facilely obtained via a one-pot synthesis route, using (NH4)6Mo7O24 4H2O (AHM) as molybdenum sources and polymethylhydrosiloxane (PMHS) as silica sources at the initial synthetic step. The optimal C/Mo molar ratio in reaction system for complete carburization of molybdenum species was 7. The carburization process of molybdenum species followed a nontopotactic route involving a MoO2 intermediate phase, which was evidenced by XRD, N2 adsorption-desorption and in situ XPS. Formation mechanism of Mo-M-SiO2 precursor was also proposed by observation of the reaction between AHM and PMHS with TEM. Furthermore, by adding TEOS into silica sources and adjusting TEOS/PMHS mass ratio, crystal phase of molybdenum carbides transferred from β-Mo2C to α-MoC1-x, and SiO2 structure changed from microporous to micro/mesoporous. Catalytic performances of samples were tested using CO hydrogenation as a probe reaction. The supported molybdenum carbides exhibited high selectivity for higher alcohol synthesis compared with bulk β-Mo2C and α-MoC1-x.展开更多
Synthesis gas derived from methanol cracking (SGMC) was applied as simulating feedstock of Fischer-Tropsch synthesis (FTS) in laboratory. With MS and GC detector, a trifle of sulfur compounds, a small amount of ox...Synthesis gas derived from methanol cracking (SGMC) was applied as simulating feedstock of Fischer-Tropsch synthesis (FTS) in laboratory. With MS and GC detector, a trifle of sulfur compounds, a small amount of oxygenates including H2O, CH3OH, DME and CO2 as well as a few of low carbon alkanes were found in the SGMC. After purification, the sulfur compounds, H2O, CH3OH and DME could be eliminated efficiently from the SGMC while CO2 and the low carbon alkanes were partly removed. When the unpurified SGMC, the desufurized SGMC and the totally purified SGMC were sequentially applied in cobalt-based FTS, the catalytic performance of Co/ZrO2/SiO2 catalyst was gradually improved corresponding to the degree of purification. The untreated SGMC led to the serious deactivation of the cobalt catalyst, the partially treated SGMC slowed down the deactivation rate and the totally purified SGMC resulted in little deactivation of the catalyst, which was similar to what the pure synthesis gas (the mixture of pure H2 and CO) did. The results indicated that the SGMC should be purified and the purification course used in this paper was effective for the SGMC. Furthermore, the totally purified SGMC could substitute for the pure synthesis gas in cobalt FTS.展开更多
In order to reveal the dissolution behavior of iron tailings in blast furnace slag,we studied the main component of silica in iron tailings.First,edge contour features need to be established to represent the melting p...In order to reveal the dissolution behavior of iron tailings in blast furnace slag,we studied the main component of silica in iron tailings.First,edge contour features need to be established to represent the melting process of silica.We choose shape,perimeter,area and generalized radius as objects.By independently analyzing the influence of these four indexes on the melting rate,the area and shape were selected as the characteristic parameters of the edge contour of the silica particles.Then,the actual melting rate of the silica is estimated by the edge contour feature index.Finally,we can calculate the melting rate of the first second of three time periods of 0.00010312mm^3/s,0.0002399mm^3/s,0.0000538mm^3/s.展开更多
基金supported by the National Key Research and Development Program of China(2021YFC2501800)Leader Project of Henan Province Health Young and Middle-aged Professor(HNSWJW2020013).
文摘BACKGROUND:Patients with diabetes mellitus(DM)are vulnerable to community-acquired pneumonia(CAP),which have a high mortality rate.We aimed to investigate the value of heparin-binding protein(HBP)as a prognostic marker of mortality in patients with DM and CAP.METHODS:This retrospective study included CAP patients who were tested for HBP at intensive care unit(ICU)admission from January 2019 to April 2020.Patients were allocated to the DM or non-DM group and paired with propensity score matching.Baseline characteristics and clinical outcomes up to 90 days were evaluated.The primary outcome was the 10-day mortality.Receiver operating characteristic(ROC)curves,Kaplan-Meier analysis,and Cox regression were used for statistical analysis.RESULTS:Among 152 enrolled patients,60 pairs were successfully matched.There was no significant difference in 10-day mortality,while more patients in the DM group died within 28 d(P=0.024)and 90 d(P=0.008).In the DM group,HBP levels at ICU admission were higher in 10-day non-survivors than in 10-day survivors(median 182.21[IQR:55.43-300]ng/ml vs.median 66.40[IQR:34.13-107.85]ng/mL,P=0.019),and HBP levels could predict the 10-day mortality with an area under the ROC curve of 0.747.The cut-off value,sensitivity,and specificity were 160.6 ng/mL,66.7%,and 90.2%,respectively.Multivariate Cox regression analysis indicated that HBP was an independent prognostic factor for 10-day(HR 7.196,95%CI:1.596-32.455,P=0.01),28-day(HR 4.381,95%CI:1.449-13.245,P=0.009),and 90-day mortality(HR 4.581,95%CI:1.637-12.819,P=0.004)in patients with DM.CONCLUSION:Plasma HBP at ICU admission was associated with the 10-day,28-day,and 90-day mortality,and might be a prognostic factor in patients with DM and CAP.
基金supported by “San Ming” Project of Shenzhen, China (No. SZSM201612051)National Natural Science Foundation of China (No. 81972240)。
文摘Colorectal cancer has a high incidence and mortality rate in China, with the majority of cases being middle and low rectal cancer. Surgical intervention is currently the main treatment modality for locally advanced rectal cancer, with the common goal of improving oncological outcomes while preserving function. The controversy regarding the circumferential resection margin distance in rectal cancer surgery has been resolved. With the promotion of neoadjuvant therapy concepts and advancements in technology, treatment strategies have become more diverse.Following tumor downstaging, there is an increasing trend towards extending the safe distance of distal rectal margin. This provides more opportunities for patients with low rectal cancer to preserve their anal function.However, there is currently no consensus on the specific distance of distal resection margin.
文摘The build-up of misfoldedα-synuclein(α-syn)in the central nervous system is the pathological hallmark of a number of neurodegenerative diseases that are known asα-synucleinopathies.These include Parkinson’s disease(PD),Parkinson’s disease with dementia(PDD),dementia with Lewy body(LB),multiple system atrophy(MSA),and a subset of Alzheimer’s disease.Growing evidence underscores that the intercellular transmission and amplification of pathologicalα-syn are critical processes underlying the progression ofα-synucleinopathies(Peng et al.,2020),and as such,the study of these processes could lead to the identification of promising therapeutics to mitigate disease progression.Most previous studies have focused solely on pathological seeds in relation to disease progression.
基金the State Key Fundamental Research Program(Ministry of Science and Technology of China,No.2011CBA00501)Shanghai Municipal Science and Technology Commission,China(Grant No:11DZ1200300)the Foundation of State Key Laboratory of Coal Conversion(Grant No:1112610)
文摘Cu-Fe composite oxides were prepared by co-precipitation method and tested for higher alcohol synthesis from syngas. The selectivity to C2+OH and C6+OH in alcohol distribution was very high while the methane product fraction in hydrocarbon distribution was rather low, demonstrating a promising potential in higher alcohols synthesis from syngas. The distribution of alcohols and hydrocarbons approximately obeyed Anderson-Schulz-Flory distribution with similar chain growth probability, indicating alcohols and hydrocarbons derived from the same intermediates. The effects of Cu/Fe molar ratio, reaction temperature and gas hourly space velocity (GHSV) on catalytic performance were studied in detail. The sample with a Cu/Fe molar ratio of 10/1 exhibited the best catalytic performance. Higher reaction temperature accelerated water-gas-shift reaction and led to lower total alcohols selectivity. GHSV showed great effect on catalytic performance and higher GHSV increased the total alcohol selectivity, indicating there existed visible dehydration reaction of alcohol into hydrocarbon.
基金financial supports provided by the National Natural Science Foundation of China (21406255)the Shanghai Science and Technology Committee (16dz1207200)the Youth Innovation Promotion Association CAS (2015231)
文摘The directly selective hydrogenolysis of xylitol to ethylene glycol(EG) and 1,2-propylene glycol(1,2-PDO)was performed on Cu–Ni–ZrO_2 catalysts prepared by a co-precipitation method. Upon optimizing the reaction conditions(518 K, 4.0 MPaH_2 and 3 h), 97.0% conversion of xylitol and 63.1% yield of glycols were obtained in water without extra inorganic base. The catalyst still remained stable activity after six cycles and above 80% total selectivity of glycols was obtained when using 20.0% xylitol concentration. XRD, TEM and ICP results indicated that Cu–Ni–ZrO_2 catalysts possess favorable stability. Cu and Ni are beneficial to the cleavage of C–O and C–H bond, respectively. To reduce the hydrogen consumption, isopropanol was added as in-situ hydrogen source and 96.4% conversion of xylitol with 43.6% yield of glycols were realized.
文摘The X-ray photoelectron spectroscopy (XPS) was used to investigate the surface characteristic of potassium-promoted or un-promoted both β-Mo2C and α-MoC1-x pretreated by syngas at different temperatures,and the promotional effect of potassium on the catalytic performance was also studied.XPS results revealed that the content of surface Mo and its valence distribution between β-Mo2C and α-MoC1-x were quite different.Promoted by potassium,the remarkable changes were observed for surface composition and valence of Mo distribution over β-Mo2C.Potassium had strong electronic effect on β-Mo2C,which led to a higher Mo4+ content.On the contrary,potassium had little electronic effect on α-MoC1-x,and K-Mo interaction was weak.Therefore,Mo0 and Mo2+ became the dominant species on the catalyst surface,and the Mo4+ content showed almost no increase as the pretreatment temperature enhanced.In terms of catalytic performance of molybdenum carbides,the increase in Mo0 most likely explained the increase in hydrocarbon selectivity,yet Mo4+ might be responsible for the alcohols synthesis.
基金supported by the National Key Project for Basic Research of China (973 Project) (No. 2005CB221400)
文摘Nickel and potassium co-modified β-Mo2C catalysts were prepared and used for CO hydrogenation reaction. The major products over β-Mo2C were C1-C4 hydrocarbons, only few alcohols were obtained. Addition of potassium resulted in remarkable selectivity shift from hydrocarbons to alcohols at the expense of CO conversion over β-Mo2C. Moreover, it was found that potassium enhanced the ability of chain propagation with a higher C2+OH production. Modified by nickel,β-Mo2C showed a relatively high CO conversion, however, the products were similar to those of pure β-Mo2C. When co-modified by nickel and potassium,β-Mo2C exhibited high activity and selectivity towards mixed alcohols synthesis, and also the whole chain propagation to produce alcohols especially for the stage of C1 OH to C2OH was remarkably enhanced. It was concluded that the Ni and K had, to some extent, synergistic effect on CO conversion.
基金financially supported by the National Science Foundation of China (21671132)Shanghai Science and Technology Committee(16dz1207200)the Youth Innovation Promotion Association CAS(2015231)
文摘MnOx-promoted Ni-based catalyst supported by ZnO was developed to selectively hydrogenate glucose into polyols in water at 523 K with a yield of 64.9%. Using glucose, sorbitol, glycerol and LA as the rawmaterials, the roles of nickel, ZnO and MnOx were investigated. The results show that nickel provided a new pathway of glucose to sorbitol and played an important role in the hydrogenation of C3 intermediates to 1,2-propanediol(1,2-PDO). The high yield of 1, 2-PDO was attributed to effective C–C bond cleavage performance of ZnO support promoted by MnOx. ZnO and MnOx contribute to the conversion of glycerol to lactic acid(LA) and LA to 1, 2-PDO, respectively. A concise pathway for hydrogenation of glucose over Ni-based catalyst was proposed.
基金supported by grants from the Guangdong Provincial Science and Technology Plan Project(2016B020201002)the Science and Technology Research Project of Beijing Forestry University(2018WS01)+2 种基金the Research and Development Project of Beijing Forestry University(2016BLPX13)the National Natural Science Foundation of China(31700581)the Key Project of the National Forestry Bureau(2012–06)。
文摘Chinese fir(Cunninghamia lanceolata(Lamb.)Hook),a fast-growing and economically important timber tree species in China,is widely used in construction,furniture,and paper manufacture but has a long breeding cycle.Chemical mutagens,such as ethyl methane sulfonate(EMS)and sodium azide(SA),are widely used in crops such as rice,wheat,cotton,soybean and sugarcane but their utility for tree breeding is unknown.In this study we examined the effects of EMS and S A on Chinese fir seed germination and growth.Chinese fir seeds were treated with the two chemical mutagens;were planted in Jiangle County,Fujian Province,China;and their heights were measured from 2011 to2017.The concentrations and durations of treatment with the two chemical mutagens were significantly associated with the Chinese fir seedling and mortality rates,as well as with the heights of trees from the seedling stage to 3 years old.We also generated 127 mutants with abnormal branches and reproductive growth.We report here the effects of two chemical mutagens on Chinese fir breeding;our data will contribute to knowledge of the utility of EMS and SA in forestry.
文摘Based on the difference of hydroxy group configuration on the special adsorption and coordination of phosphate on the dispersed α-Fe2O3 nanodisks with diameter of 150-200 nm different planes of α-Fe2O3 nanoparticles, using (001) plane of α-Fe2O3, well-crystallized and well and thickness of 40-80 nm were synthesized via a hydrotherrnal method. The magnetic properties of synthesized nanodisks were investigated. It was found that the nanodisks possessed a saturation magnetization (Ms) of 0.38 emu/g, a rernanent magnetization (Mr) of 0.031 ernu/g and a coercivity of 452.91 Oe at room temperature. The Mr and coercivity of synthesized α-Fe2O3 nanodisks are higher and the Ms is lower than those of other previously reported α-Fe2O3 nanostructures.
基金supported by the Key Project of Chinese National Programs for Fundamental Research and Development(973 Program-2005CB221400)
文摘Fe modified and un-modified K/Mo2C were prepared and investigated as catalysts for CO hydrogenation reaction. Compared with K/Mo2C catalyst, the addition of Fe increased the production of alcohols, especially the C2+OH. Meanwhile, considerable amounts of C5+ hydrocar- bons and C2= -C4= were formed, whereas methane selectivity greatly decreased. Also, the activity and selectivity of the catalyst were readily affected by the reaction pressure and temperature employed. According to the XPS results, Mo4+ might be responsible for the production of alcohols, whereas the low valence state of Mo species such as Mo^0 and/or Mo^2+ might be account for the high activity and selectivity toward hydrocarbons.
文摘Highly dispersed Cu-base catalyst has been prepared via thermal decomposition of layered double hydroxides precursors. The XRD pattern and the HRTEM images of the as prepared catalyst confirmed the high dispersion of Cu and Fe ions. Results show that the catalyst has a relatively high selectivity of alkanes at low temperature.
基金This work was supported by the Doctoral Scientific Research Starting Foundation of Henan University of Science and Technology(13480089)National Nature Science Foundation of China(31570677)+1 种基金the National Key R&D Program of China(2017YFD0600503)the National Forestry and Grassland Administration of Science and Technology Development Center Project(2016007).
文摘Robinia pseudoacacia is an important afforesta-tion tree introduced to China in 1878.In the present study,we examined the genetic diversity among 687 strains rep-resenting four improved varieties and two secondary prov-enances,comprising 641 clones and 46 seedlings.Ninety-one simple sequence repeats(SSRs)were selected through segregation analysis and polymorphism characterization,and all sampled individuals were genotyped using well-characterized SSR markers.After excluding loci with non-neutral equilibrium,missing locus data and null alleles,we used 36 primer pairs to assess the genetic diversity of these germplasm resources,revealing vast genetic differentiation among the samples,with an average of 8.352 alleles per locus and a mean Shannon′s index of 1.302.At the popula-tion level,the partitioning of variability was assessed using analysis of molecular variance,which revealed 93%and 7%variation within and among collection sites,respectively.Four clusters were detected using structure analysis,indi-cating a degree of genetic differentiation among the six populations.Insights into the genetic diversity and structure of R.pseudoacacia provide a theoretical basis for the con-servation,breeding and sustainable development in China.
基金financial support by the National Natural Science Foundation of China (21273151)China Ministry of Science and Technology (2016YFA0202802)Strategic Priority Research Program of the Chinese Academy of Sciences (XDA07040200)
文摘To gain deep insight into the Morphological effect of NixMg1-xO catalysts on the reaction of CO2reforming with methane, we designed and fabricated three different spatial structural NixMg1-xO catalysts.These NixMg1-xO catalysts with specific models such as rod, sheet and sphere, exhibited various activity and stability in CO2reforming reaction. Herein NixMg1-xO nanorods displayed higher catalytic activity, in which methane conversion was up to 72% and CO2conversion was 64% at 670°C with a space velocity of 79,200 mL/(gcath), compared with nanosheet and nanosphere counterparts. Furthermore, both catalysts of NixMg1-xO nanorod and nanosheet showed a high resistance toward coke deposition and sintering of active sites in the process of CO2reforming of methane.
基金supported by Natural Science Foundation of China(91945301)Program of Shanghai Academic/Technology Research Leader(20XD1404000)+2 种基金Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(QYZDB-SSWSLH035)the“Transformational Technologies for Clean Energy and Demonstration”and Strategic Priority Research Program of CAS(XDA21020600)the Youth Innovation Promotion Association of CAS。
文摘CO_(2)hydrogenation to value-added chemicals is a promising pathway to solve CO_(2)-relevant environmental problems but still remains a great challenge.Herein,we report a CeO_(2)nanostructure supported Rh single atoms(Rh-SAs/CeO_(2))catalyst and was used for the efficient CO_(2)hydrogenation to HCOOH.The Rh-SAs/CeO_(2)exhibited high catalytic activity with turnover numbers(TON)up to 221 at 200℃,which was 4-fold to that of CeO_(2)supported Rh nanoparticles(Rh-NPs/CeO_(2)).Moreover,HCOOH selectivity for Rh-SAs/CeO_(2)reached 85%,much higher than that of Rh-NPs/CeO_(2)(46%).Mechanism studies revealed that Rh single atoms in the Rh-SAs/CeO_(2)with high metal atoms utilization efficiency not only provided abundant active sites to promote the catalytic activity,but also suppressed the decomposition of HCOOH to CO and benefited the formation of HCOOH.
基金supported by the National Natural Science Foundation of China (No. 200573128)the Natural Science Foundation of Shanxi Province, China (No. 20051025)the Natural Science Foundation for Young Scientists of Shanxi Province, China (No. 2006021031)
文摘A novel synthesis route to obtain highly dispersed molybdenum carbides in porous silica is described. The synthesis was carried out by a single-step heat treatment of molybdenum-containing and methyl-modified silica (Mo-M-SiO2) in argon atmosphere at 973 K. Mo-M-SiO2 precursor was facilely obtained via a one-pot synthesis route, using (NH4)6Mo7O24 4H2O (AHM) as molybdenum sources and polymethylhydrosiloxane (PMHS) as silica sources at the initial synthetic step. The optimal C/Mo molar ratio in reaction system for complete carburization of molybdenum species was 7. The carburization process of molybdenum species followed a nontopotactic route involving a MoO2 intermediate phase, which was evidenced by XRD, N2 adsorption-desorption and in situ XPS. Formation mechanism of Mo-M-SiO2 precursor was also proposed by observation of the reaction between AHM and PMHS with TEM. Furthermore, by adding TEOS into silica sources and adjusting TEOS/PMHS mass ratio, crystal phase of molybdenum carbides transferred from β-Mo2C to α-MoC1-x, and SiO2 structure changed from microporous to micro/mesoporous. Catalytic performances of samples were tested using CO hydrogenation as a probe reaction. The supported molybdenum carbides exhibited high selectivity for higher alcohol synthesis compared with bulk β-Mo2C and α-MoC1-x.
基金Financial supported from National Natural Foundation of China (20590361 and 20303026) and State Key FoundationProgram for Development and Research of China (2005cb221402).
文摘Synthesis gas derived from methanol cracking (SGMC) was applied as simulating feedstock of Fischer-Tropsch synthesis (FTS) in laboratory. With MS and GC detector, a trifle of sulfur compounds, a small amount of oxygenates including H2O, CH3OH, DME and CO2 as well as a few of low carbon alkanes were found in the SGMC. After purification, the sulfur compounds, H2O, CH3OH and DME could be eliminated efficiently from the SGMC while CO2 and the low carbon alkanes were partly removed. When the unpurified SGMC, the desufurized SGMC and the totally purified SGMC were sequentially applied in cobalt-based FTS, the catalytic performance of Co/ZrO2/SiO2 catalyst was gradually improved corresponding to the degree of purification. The untreated SGMC led to the serious deactivation of the cobalt catalyst, the partially treated SGMC slowed down the deactivation rate and the totally purified SGMC resulted in little deactivation of the catalyst, which was similar to what the pure synthesis gas (the mixture of pure H2 and CO) did. The results indicated that the SGMC should be purified and the purification course used in this paper was effective for the SGMC. Furthermore, the totally purified SGMC could substitute for the pure synthesis gas in cobalt FTS.
文摘In order to reveal the dissolution behavior of iron tailings in blast furnace slag,we studied the main component of silica in iron tailings.First,edge contour features need to be established to represent the melting process of silica.We choose shape,perimeter,area and generalized radius as objects.By independently analyzing the influence of these four indexes on the melting rate,the area and shape were selected as the characteristic parameters of the edge contour of the silica particles.Then,the actual melting rate of the silica is estimated by the edge contour feature index.Finally,we can calculate the melting rate of the first second of three time periods of 0.00010312mm^3/s,0.0002399mm^3/s,0.0000538mm^3/s.