Insights into the Origins of Solar-Assisted Electrochemical Water Oxidation in Allotropic Co_(5.47)N/CON Heterojunctions

Solar irradiation can efficiently promote the kinetics of the oxygen evolution reaction(OER)during water splitting,where heterojunction catalysts exhibit excellent photoresponsive properties.However,insights into the origins of photoassisted OER catalysis remain unclear,especially the interfaced promotion under convergent solar irradiation(CSI).Herein,novel allotropic Co_(5.47)N/CoN heterojunctions were synthesized,and corresponding OER mechanisms under CSI were comprehensively uncovered from physical and chemical aspects using the in situ Raman technique and electrochemical cyclic voltammetry method.Our results provide a unique mechanism where high-energy UV light promotes the Co^(3+/4+)conversion process in addition to the ordinary photoelectric effect excitation of the Co^(2+)material.Importantly,visible light under CSI can produce a photothermal effect for Co^(2+)excitation and Co^(3+/4+)conversion,which promotes the OER significantly more than the usual photoelectric effect.As a result,Co_(5.47)N/CoN(containing 28%CoN)obtained 317.9%OER enhancement,which provides a pathway for constructing excellent OER catalysts.

Manipulating d-d orbital hybridization induced by Mo-doped Co_(9)S_(8) nanorod arrays for high-efficiency water electrolysis

Precisely refining the electronic structure of electrocatalysts represents a powerful approach to further optimize the electrocatalytic performance.Herein,we demonstrate an ingenious d-d orbital hybridization concept to construct Mo-doped Co_(9)S_(8) nanorod arrays aligned on carbon cloth(CC)substrate(abbreviated as Mo-Co_(9)S_(8)@CC hereafter)as a high-efficiency bifunctional electrocatalyst toward water electrolysis.It has experimentally and theoretically validated that the 4d-3d orbital coupling between Mo dopant and Co site can effectively optimize the H_(2)O activation energy and lower H^(*)adsorption energy barrier,thereby leading to enhanced hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)activities.Thanks to the unique electronic and geometrical advantages,the optimized Mo-Co_(9)S_(8)@CC with appropriate Mo content exhibits outstanding bifunctional performance in alkaline solution,with the overpotentials of 75 and 234 mV for the delivery of a current density of 10 mA cm^(-2),small Tafel slopes of 53.8 and 39.9 mV dec~(-1)and long-term stabilities for at least 32 and 30 h for HER and OER,respectively.More impressively,a water splitting electrolylzer assembled by the self-supported Mo-Co_(9)S_(8)@CC electrode requires a low cell voltage of 1.53 V at 10 mA cm^(-2)and shows excellent stability and splendid reversibility,demonstrating a huge potential for affordable and scalable electrochemical H_(2) production.The innovational orbital hybridization strategy for electronic regulation herein provides an inspirable avenue for developing progressive electrocatalysts toward new energy systems.

Experimental study on the movement of oil spill under freeze-thaw action

Oil leakages cause environmental pollution,economic losses,and even engineering safety accidents.In cold regions,researchers urgently investigate the movement of oil spill in soils exposed to freeze-thaw cycles.In this study,a series of laboratory model experiments were carried out on the migration of oil leakage under freeze-thaw action,and the distributions of the soil temperature,unfrozen water content,and displacement were analyzed.The results showed that under freeze-thaw action,liquid water in soils migrated to the freezing front and accumulated.After the pipe cracked,oil pollutants first gathered at one side of the leak hole,and then moved around.The pipe wall temperature affected the soil temperature field,and the thermal influence range below and transverse the pipe wall(35–40 cm)was larger than that above the pipe wall(8 cm)owing to the soil surface temperature.The leaked oil's temperature would make the temperature of the surrounding soil rise.Oil would inhibit the cooling of the soils.Besides,oil migration was significantly affected by the gravity and water flow patterns.The freeze-thaw action would affect the migration of the oil,which was mainly manifested as inhibiting the diffusion and movement of oil when soils were frozen.Unfrozen water transport caused by freeze-thaw cycles would also inhibit oil migration.The research results would provide a scientific reference for understanding the relationship between the movement of oil pollutants,water,and soil temperature,and for establishing a waterheat-mass transport model in frozen soils.

FGF signaling modulates mechanotransduction/WNT signaling in progenitors during tooth root development

Stem/progenitor cells differentiate into different cell lineages during organ development and morphogenesis.Signaling pathway networks and mechanotransduction are important factors to guide the lineage commitment of stem/progenitor cells during craniofacial tissue morphogenesis.

在N掺杂碳纳米管/纳米线耦合超结构中原位固载CoNi纳米颗粒制备莫特-肖特基催化剂并用于高效电催化氧还原反应

设计开发可用于电催化氧还原反应(ORR)的高效催化剂对于推进可持续能源技术(如燃料电池和金属空气电池等)的进一步发展至关重要.然而,由于ORR涉及多电子转移过程,并且动力学迟缓,电位高,从而限制了相关技术的实际应用.到目前为止,铂族金属被认为是ORR的基准电催化剂.然而,由于铂族金属资源稀缺、价格高、催化剂稳定性不足阻碍了其在不同能源装置中的进一步应用.因此,亟需开发出高活性、低成本、耐用的ORR电催化剂,从而推进可再生能源技术的进一步发展.双金属纳米合金因具有良好的导电性、可调整的电子态且金属间存在协同效应而被认为是一种有较大应用前景的ORR催化材料.本文采用自我牺牲模板法,将均匀的Co Ni合金纳米颗粒原位封装在N掺杂碳纳米管/纳米线耦合的分层结构中,构建了莫特-肖特基电催化剂(CoNi@N-CNT/NWs),并应用于金属空气电池.采用X射线衍射、拉曼光谱、热重、BET比表面积测试、X射线光电子能谱、扫描电子显微镜和透射电镜等方法对催化剂进行了表征.扫描电子显微镜和透射电镜结果表明,复合材料呈现一维多级结构的纳米管分支/纳米线主干的层次结构.实验结果和理论计算表明,CoNi纳米合金与N掺杂碳纳米管/纳米线的整流接触可以诱导自驱动电荷在莫特-肖特基异质结上转移,从而提高了电子转移效率并调节电荷分布.此外,碳分支/主干型分层结构作为支架的建立,增加了CoNi@N-CNT/NWs材料中活性位点的暴露,避免了材料堆积或聚集,进而提高了机械稳定性,缩短了传质扩散的路径并提高了气体传质的速率.得益于结构和电子优势,CoNi@N-CNT/NWs具有较好的ORR性能,其半波电位(E1/2)为0.86 V,在0.1 molL^(-1)KOH电解质中表现出较好的稳定性.采用CoNi@N-CNT/NWs电催化剂组装的锌空电池可以实现较高的开路电压、高峰值功率密度以及大比容量和持久的循环性能,在不同ORR相关的能源装置中展示出良好的应用前景.综上所述,金属空气电池是未来最具有潜力的能源转换器件之一,双金属纳米合金的精细设计和结构调控将为氧还原催化剂的可控制备和性能优化提供新思路.

Electrospun Semiconductor-Based Nano-Heterostructures for Photocatalytic Energy Conversion and Environmental Remediation:Opportunities and Challenges

Harvesting solar energy to drive the semiconductor photocatalysis offers a promising tactic to address ever-growing challenges of both energy shortage and environmental pollution.Design and synthesis of nano-heterostructure photocatalysts with controllable components and morphologies are the key factors for achieving highly efficient photocatalytic processes.Onedimensional(1D)semiconductor nanofibers produced by electrospinning possess a large ratio of length to diameter,high ratio of surface to volume,small grain sizes,and high porosity,which are ideally suited for photocatalytic reactions from the viewpoint of structure advantage.After the secondary treatment of these nanofibers through the solvothermal,gas reduction,in situ doping,or assembly methods,the multi-component nanofibers with hierarchical nano-heterostructures can be obtained to further enhance their light absorption and charge carrier separation during the photocatalytic processes.In recent years,the electrospun semiconductorbased nano-heterostructures have become a“hot topic”in the fields of photocatalytic energy conversion and environmental remediation.This review article summarizes the recent progress in electrospinning synthesis of various kinds of high-performance semiconductor-based nano-heterostructure photocatalysts for H2 production,CO_(2) reduction,and decomposition of pollutants.The future perspectives of these materials are also discussed.

Effect of cold stratification on the temperature range for germination of Pinus koraiensis

Germination at low spring temperatures may offer a competitive advantage for the growth and survival of plant species inhabiting temperate forest ecosystems.Pinus koraiensis is a dominant species in temperate forests of northeastern China.Its seeds exhibit primary morphophysiological dormancy following dispersal in autumn,limiting natural or artificial regeneration:direct seeding and planting seedlings in spring.The aim of this study was to determine the optimum cold stratification temperature that induces germination to increase towards lower temperatures.Seeds from two populations(Changbaishan and Liangshui)were cold stratified at 0,5 and 10℃.Germination to incubation temperatures(10/5,20/10,25/15 and 30/20℃;14/10 h day/night)were determined after 2 and 4 weeks,and 5.5 and6.5 months of cold stratification.After 5.5 months,approximately 68-91%of seeds from both populations germinated at incubation temperatures of 25/15℃and 30/20℃,regardless of cold stratification temperatures.When the cold stratification temperature was reduced to 0℃and the period increased to 6.5 months,germination at 10/5℃significantly improved,reaching 37%and 64%for the Changbaishan and Liangshui populations,respectively.After 6.5 months of cold stratification,there was a significant linear regression between cold stratification temperatures and germination at10/5℃.The range in temperatures allowing for germination gradually expanded to include lower temperatures with decreasing cold stratification temperatures from 10 to 5℃and further to 0℃.

Squeezing More Past Knowledge for Online Class-Incremental Continual Learning

Continual learning(CL)studies the problem of learning to accumulate knowledge over time from a stream of data.A crucial challenge is that neural networks suffer from performance degradation on previously seen data,known as catastrophic forgetting,due to allowing parameter sharing.In this work,we consider a more practical online class-incremental CL setting,where the model learns new samples in an online manner and may continuously experience new classes.Moreover,prior knowledge is unavailable during training and evaluation.Existing works usually explore sample usages from a single dimension,which ignores a lot of valuable supervisory information.To better tackle the setting,we propose a novel replay-based CL method,which leverages multi-level representations produced by the intermediate process of training samples for replay and strengthens supervision to consolidate previous knowledge.Specifically,besides the previous raw samples,we store the corresponding logits and features in the memory.Furthermore,to imitate the prediction of the past model,we construct extra constraints by leveraging multi-level information stored in the memory.With the same number of samples for replay,our method can use more past knowledge to prevent interference.We conduct extensive evaluations on several popular CL datasets,and experiments show that our method consistently outperforms state-of-the-art methods with various sizes of episodic memory.We further provide a detailed analysis of these results and demonstrate that our method is more viable in practical scenarios.

Synergistic effect of Co（Ⅱ）-hole and Pt-electron cocatalysts for enhanced photocatalytic hydrogen evolution performance of P-doped g-C3N4

g-C3N4 is a metal-free semiconductor and a potential candidate for photocatalytic H2 production,however,the drawbacks,rapid recombination rate and limited migration efficiency of photogenerated carriers,restrict its photocatalytic activity.Herein,Co(II)as a hole cocatalyst modified P-doped g-C3N4 were successfully prepared to ameliorate the separation efficiency of photoinduced carriers and enhance the photocatalytic hydrogen production.The photocatalytic results demonstrated that the P-doped g-C3N4(PCN)exhibited higher photocatalytic activity compared with pure g-C3N4,while Co(II)/PCN photocatalyst exhibited further enhancement of photocatalytic performance.The proposed possible mechanism based on various characterizations is that P-doping can modulate the electronic structure of g-C3N4 to boost the separation of photogenerated-e-and h+;while the synergistic effect of both Co(II)(as hole cocatalyst)and Pt(as electron cocatalyst)can not only lead to the directional shunting of photogenerated e+-h?pairs,but further accelerate the photogenerated electrons transfer to Pt in order to join the photocatalytic reduction process for hydrogen evolution.As a result,the transportation and separation of photoinduced carriers were accelerated to greatest extent in the Pt/Co(II)/PCN photocatalyst.

Characterization of a new hexaploid triticale 6D(6A) substitution line with increased grain weight and decreased spikelet number

Hexaploid triticale(×Triticosecale,AABBRR)is an important forage crop and a promising energy plant.Transferring D-genome chromosomes or segments from common wheat(Triticum aestivum)into hexaploid triticale is attractive in improving its economically important traits.Here,a hexaploid triticale 6D(6A)substitution line Lin 456 derived from the cross between the octoploid triticale line H400 and the hexaploid wheat Lin 56 was identified and analyzed by genomic in situ hybridization(GISH),fluorescence in situ hybridization(FISH),and molecular markers.The GISH analysis showed that Lin 456 is a hexaploid triticalewith 14 rye(Secale cereale)chromosomes and 28 wheat chromosomes,whereas non-denaturing fluorescence in situ hybridization(ND-FISH)and molecular marker analysis revealed that it is a 6D(6A)substitution line.In contrast to previous studies,the signal of Oligo-pSc119.2 was observed at the distal end of 6DL in Lin 456.The wheat chromosome 6D was associatedwith increased grain weight and decreased spikelet number using the genotypic data combined with the phenotypes of the F2 population in the three environments.The thousand-grain weight and grain width in the substitution individuals were significantly higher than those in the non-substitution individuals in the F2 population across the three environments.We propose that the hexaploid triticale 6D(6A)substitution line Lin 456 can be a valuable and promising donor stock for genetic improvement during triticale breeding.

Effect of ultramicropores and inner space of carbon materials on the capacitive sodium storage performance

1.Introduction Carbon materials have been widely investigated as the anode materials for Na+storage due to their moderate capacity,good stability,and low cost.The Na+storage mechanisms of carbon are generally classified into diffusion-controlled interlayer insertion/desertion and capacitive-controlled surface adsorption/desorption[1].

Direct incorporation of paraffin wax as phase change material into mass concrete for temperature control: mechanical and thermal properties

Taking advantage of heat absorbing and releasing capability of phase change material(PCM),Paraffin wax-based concrete was prepared to assess its automatic temperature control performance.The mechanical properties of PCM concrete with eight different Paraffin wax contents were tested by the cube compression test and four-point bending test.The more Paraffin wax incorporated,the greater loss of the compressive strength and bending strength.Based on the mechanical results,four contents of Paraffin wax were chosen for studying PCM concrete's thermal properties,including thermal conductivity,thermal diffusivity,specific heat capacity,thermal expansion coefficient and adiabatic temperature rise.When the Paraffin wax content increases from 10%to 20%,the thermal conductivity and the thermal diffusivity decrease from 7.31 kJ/(m·h·°C)to 7.10 kJ/(m·h·°C)and from 3.03×10−3 m2/h to 2.44×10−3 m2/h,respectively.Meanwhile the specific heat capacity and thermal expansion coefficient rise from 5.38×10−1 kJ/(kg·°C)to 5.76×10−1 kJ/(kg·°C)and from 9.63×10−6/°C to 14.02×10−6/°C,respectively.The adiabatic temperature rise is found to decrease with an increasing Paraffin wax content.Considering both the mechanical and thermal properties,15%of Paraffin wax was elected for the mass concrete model test,and the model test results confirm the effect of Paraffin wax in automatic mass concrete temperature control.

Expression and significance of vascular endothelial growth factor D in gastric cancer

Objective: To investigate the expression of vascular endothelial growth factor D (VEGF-D) in gastric cancer and its relationship with lymph node metastasis. Methods: 100 cases of gastric carcinoma tissues (50 cases with lymph node metastasis, 50 cases negative) and 30 cases of normal gastric tissues were gathered to detect the expressions of VEGF-C and D proteins by immunohistochemistry. Results: VEGF-C and D were revealed in cytoplasm of gastric carcinoma tissues and normal gastric tissues. The positive rates of VEGF-C and D expressions were significantly higher in gastric cancer tissues than those in the normal ones (51%, 60% vs 10%, 20% respectively; both P < 0.05). There were significant correlations be- tween the positive expression of VEGF-D and lymph node metastasis, lymphatic invasion, positive expression of VEGF-C, but not with tumour size, tissue differentiation, and venous invasion. Conclusion: The expression of VEGF-D is closely related to lymph node metastasis in gastric carcinoma.

A multi-index coupling system of ice slope stability and its application

Based on the Simplified Bishop Method, the minimum safety factor of ice slope both with and without tension cracks is calculated in combination with triaxial compression tests. It is found that there exists a critical depth for each crack. Then, factors influencing ice slope stability such as slope ratio, slope height, ice cohesion, internal friction angle, unit weight and temperature were analyzed. Meanwhile, a regression equation between the aforementioned factors and safety factor is obtained, with which sensitivity analysis is carried out. The performance function is built in combination with random distribution of physical and mechanical parameters to analyze the reliability index. The Advanced First Order Second Moment Method is employed on the solution to the perfor- mance function. The one-way coupling system of ice slope stability is therefore formed based on safety factor and reliability index. Finally, an illustrated example of ice slope is provided, which shows that failure probability is relatively high, up to 6.18%, alt- hough safety factor is 2.77. Thus, it is objective and reasonable to apply the coupled system method to the slope stability rating.

NaGd_(0.4)Eu_(0.6)Mg_(1-x)Zn_(x)WO_(6)solid solution red phosphors:Microstructure variation and luminescence enhancement induced by Zn^(2+)-doping

Red phosphor is an important component of the phosphor-converted white light-emitting diodes(pcWLEDs).The development of the novel red phosphor with excellent luminescence properties is of great significance for high performance WLEDs.In this study,NaGd_(0.4)Eu_(0.6)Mg_(1-x)Zn_(x)WO_(6)red phosphors with excellent luminescence properties were successfully synthesized and systematically investigated.Our results show that the Zn^(2+)-doping concentration has significant effect on the microstructures and luminescence properties of the NaGd_(0.4)Eu_(0.6)Mg_(1-x)Zn_(x)WO_(6)phosphors.The NaGd_(0.4)Eu_(0.6)Mg_(1-x)ZnxWO_(6)(0≤x≤0.7)samples are well crystallized pure solid solution sub-microcrystals,whereas the phase purity gradually decreases at 0.7<x≤1.0.The NaGd_(0.4)Eu_(0.6)Mg_(1-x)ZnxWO_(6)(0<x≤0.5)phosphors have stronger emissions than NaGd_(0.4)Eu_(0.6)MgWO_(6),and the optimized NaGd_(0.4)Eu_(0.6)Mg_(0.9)Zn_(0.1)WO_(6)phosphor possesses the best luminescence properties including thermal stability,CIE chromaticity coordinate,life time and quantum yield.The packaged WLED using NaGd_(0.4)Eu_(0.6)Mg_(0.9)Zn_(0.1)WO_(6)phosphor emits bright white light with higher CRI,lower CCT,and chromaticity coordinate close to the pure white light.The developed NaGd_(0.4)Eu_(0.6)Mg_(1-x)Zn_(x)WO_(6)phosphors have potential application in lighting and display.This work can offer an effective strategy for boosting luminescence properties of tungstate phosphors with the double perovskite structure.

Surface engineering of highly ordered Bi_(2)S_(3)film with open channels toward high-performance broadband photodetection

The highly ordered film assembled by regularly 1D nanostructures has potentialprospects in electronic,photoelectronic and other fields because of its excellentlight-trapping effect and electronic transport property.However,the controlledgrowth of highly ordered film remains a great challenge.Herein,large-area andhighly ordered Bi_(2)S_(3)film is synthesized on fluorophlogopite mica substrate bychemical vapor deposition method.The Bi2S3 film features hollowed-outcrosslinked network structure,assembled by 1D nanobelts that regularly distributein three orientations,which agrees well with the first principles calculations.Based on the as-grown Bi_(2)S_(3)film,the broadband photodetector with a responserange from 365 to 940 nm is fabricated,exhibiting a maximum responsivity upto 98.51 mA W^(–1),specific detectivity of 2.03×10^(10)Jones and fast response timeof 35.19 ms.The stable instantaneous on/off behavior for 500 cycles and reliablephotoresponse characteristics of the Bi_(2)S_(3)photodetector after storage in air for6 months confirm its excellent long-term stability and air stability.Significantly,as sensing pixel and signal receiving terminal,the device successfully achieveshigh-resolution imaging of characters of“H”,“I”and“T”,and secure transmissionof confidential information.This work shows a great potential of the largeareaand highly ordered Bi_(2)S_(3)film toward the development of future multiplefunctional photoelectronic applications.

Ultrathin curved PdNiRu nanosheets as bifunctional catalysts for oxygen reduction and ethylene glycol oxidation

Pd-based metallic nanosheets with advanced physicochemical properties have been widely prepared and employed in various electrocatalytic reactions.However,few concerns were focused on their multiple performances in different electrocatalysis.Here,highly curved and ultrathin PdNiRu nanosheets(NSs)are developed by facile wet-chemistry strategy and exhibit excellent electrocatalytic performance toward both oxygen reduction reaction(ORR)and ethylene glycol oxidation reaction(EGOR).Owing to the synergistically structural(e.g.,ultrathin,curved,defects/steps-rich)and compositional(ternary alloy)advantages,PdNiRu NSs exhibited enhanced ORR and EGOR specific/mass activities and better stability/durability than control electrocatalysts.The specific activity(5.52 mA·cm^(−2))and mass activity(1.13 A·mg_(Pd)^(−1))of the PdNiRu NSs in ORR are 4.8 and 3.4 times as the ones of commercial Pt/C,respectively.The mass activity of PdNiRu NSs(3.86 A·mg_(Pd)^(−1))in EGOR is 2.6 times as commercial Pd/C(1.51 A·mg_(Pd)^(−1)).This study is helpful for the development of desired electrocatalysts with multi-functional application in practical fuel cells.

Enhanced antibiotic degradation performance of Cd_(0.5)Zn_(0.5)S/Bi_(2)MoO_(6) S-scheme photocatalyst by carbon dot modification

S-scheme heterojunction engineering is an effective strategy to attain distinctive photocatalysts.Herein,a carbon dots modulated S-scheme hetero-structured photocatalyst of Cd_(0.5)Zn_(0.5)S nanoparticles/Bi_(2)MoO_(6) microspheres/carbon dots (CZCBM),aiming to conquer the photo-corrosion and strengthen the photocatalytic property of Cd_(0.5)Zn_(0.5)S,was developed via a facile solvothermal route.Under visible light,the optimal CZCBM-2 affords a 1.8-,1.5-,or 0.6-time reinforcement in the oxytetracycline degradation rate constant compared to Bi_(2)MoO_(6),Cd_(0.5)Zn_(0.5)S or Cd_(0.5)Zn_(0.5)S/Bi_(2)MoO_(6),which is credited to the strengthened visible-light response,increased reactive sites,and efficient dissolution of photo-carriers with optimal redox capacity because of the co-effect of carbon dots and S-scheme heterostructure.Significantly,the photo-corrosion of Cd_(0.5)Zn_(0.5)S is significantly suppressed and CZCBM-2 affords superior stability and reusability during cycling tests.Besides,CZCBM-2 can be well adapted to various environments.The toxicology appraisement unravels the decreased eco-toxicity of most intermediates compared to oxytetracycline.Lastly,an S-scheme charge transfer mechanism with carbon dots as electron reservoir in CZCBM is deduced,which uncloses that •O_(2)− and h+ dominantly account for oxytetracycline eradication and detoxification.This study demonstrates the design of unique carbon dots favored S-scheme heterostructures as an effective “Two Birds with One Stone” strategy to achieve high anti-photo-corrosion performance and reinforced photocatalytic performance of sulfides.

红松种子休眠状态的变化调控种子萌发的季节性时间

种子休眠能够确保幼苗在一个季节性变化的环境中选择适宜的季节建植。红松(Pinus koraiensis)种子在秋季落下之后具有形态生理休眠。一小部分种子在落下之后的第一个春季萌发,但大部分种子在第二个春季萌发,目前尚不清楚休眠状态如何驱动这种萌发特性。在2018年10月中旬,在中国东北黑龙江省丰林国家级自然保护区的凋落物和土层之间埋藏新鲜的红松种子,并且隔一段时间取出,测定种子的野外萌发率、种胚生长情况、种子活力和室内萌发率。形态生理休眠的生理休眠部分在第一个冬季逐渐解除,但在第一个夏季被再次诱导;再次被诱导的生理休眠在第二个秋、冬季解除。形态生理休眠的形态休眠部分在第一个夏季逐渐缓慢解除,但在第二个早、中秋季迅速解除。在第二个春季,红松种子完全解除形态生理休眠。种子的生理休眠解除,但形态休眠仍然存在,导致其在第一个春季的野外萌发率非常低。种子的形态和生理休眠均解除,导致大部分种子能在第二个春季相对较低的温度(昼夜温度在10/5°C以上)下萌发。红松种子为形态生理休眠种子的休眠状态变化研究提供了示例。