Experimental investigation on coal pore-fracture variation and fractal characteristics synergistically affected by solvents for improving clean gas extraction

Chemical solvents instead of pure water being as hydraulic fracturing fluid could effectively increase permeability and improve clean methane extraction efficiency.However,pore-fracture variation features of lean coal synergistically affected by solvents have not been fully understood.Ultrasonic testing,nuclear magnetic resonance analysis,liquid phase mass spectrometry was adopted to comprehensively analyze pore-fracture change characteristics of lean coal treated by combined solvent(NMP and CS_(2)).Meanwhile,quantitative characterization of above changing properties was conducted using geometric fractal theory.Relationship model between permeability,fractal dimension and porosity were established.Results indicate that the end face fractures of coal are well developed after CS2and combined solvent treatments,of which,end face box-counting fractal dimensions range from 1.1227 to 1.4767.Maximum decreases in ultrasonic longitudinal wave velocity of coal affected by NMP,CS_(2)and combined solvent are 2.700%,20.521%,22.454%,respectively.Solvent treatments could lead to increasing amount of both mesopores and macropores.Decrease ratio of fractal dimension Dsis 0.259%–2.159%,while permeability increases ratio of NMR ranges from 0.1904 to 6.4486.Meanwhile,combined solvent could dissolve coal polar and non-polar small molecules and expand flow space.Results could provide reference for solvent selection and parameter optimization of permeability-enhancement technology.

Investigation and Analysis on Agricultural Resources in the Main Living Areas of Pumi Nationality in Yunnan Province

[Objective] To fully grasp the living environment and the use of agricultural resources of Pumi nationality, a minority group specific in Yunnan. [Methods]Field investigation and analysis were conducted on the social economic conditions, living environment, types of agricultural resources and their use in the main inhabitances of Pumi people including Yulong, Ninglang, Lanping and Weixi County in Yunnan. [Result] There are certain differences in social and economic situations of the four counties, and the ecological environment is generally good. The main agricultural resources in villages under investigation include beans and coarse cereals, while there are certain differences among other agricultural resources due to their location. [Conclusion] The living environment of the main inhabitances of Pumi people in Yunnan is good and there are plenty and characteristic agricultural resources which have certain potentiality for development in the future.

An investigation of chemically deposited Ni-P alloys by EXAFS and XRD

Five samples of chemically desposited Ni-P amorphous alloys were prepared and inves- tigated.In these amorphous alloys there are Ni-P atom groups in which phosphorus and nickel are connected with strong interaction.Nickel atoms and Ni-P groups are deposited in a random manner on the surface of matrix and a quasilayer structure is formed.The spacing between two layers in alloys resembles that in(111)plane in the nickel crystal.Therefore there is a peak at the same position of 2θ=44.4° as that of the(111)reflection of crystalline nickel in the X-ray powder diffraction pat- tern of alloys.However,the dimension of Ni-P groups is different from that of a nickel atom and the atomic arrangement in the layer is in disorder.These result in the space change and there is a distribution of spacing around the average.As a consequence of distribution of spacings,the peak at 2θ=44.4° is broadened and enhanced as the amount of P increases.

N_2O emissions from agricultural soils in the North China Plain: the effect of chemical nitrogen fertilizer and organic manure

An enclosed chamber technique was used to measure N 2O emissions from intensively agricultural soils of the North China Plain during the periods of 1995—1996 and 1997—1998, to reflect distinct components of winter wheat and summer maize growing seasons. The results showed that the continuous application of fertilizer in agricultural soils increased N\-2O emissions by a factor of 24.1—28.1, the calculated annual chemical N fertilizer\|transformed N\-2O\|N emissions was 0.67%. Our results indicated that the application of organic manure also had a significant influence on soil N 2O emissions, which combined with the use of chemical N increased about 20% in a year. It was calculated that there were about 0.11% N of organic manure transformed as N 2O N. Annual mean N 2O emission from our study area of fertilized soils was estimated to be 57.1 μgN 2O/(m 2·h). A weak correlation was also found between N 2O emissions and soil available nitrogen content NH + 4.

Investigation and Analysis of Agricultural Cold Chain Logistics and Its Development Strategy in Heilongjiang Province

Accelerating the development of agricultural cold chain logistics is of great significance to improve the competitiveness of agricultural products,increase rural incomes and ensure food security. The present situation and main problems of agricultural cold chain logistics in Heilongjiang Province were analyzed from five aspects,such as the scale of construction,infrastructure,status quo of cold chain logistics technology,cold chain logistics enterprises and development environment,and proposed that Heilongjiang Province should focus on the development of poultry,fruit and vegetable,aquatic products,and processed food cold chain,then the strategic implementation measures for above areas were put forward.

Chemicals,Energy,and Biomaterials from Agricultural Waste Resources in South China

Owing to its subtropical or tropical environment and climate,South China is home to unique agricultural crops such as sugar cane,pineapple,banana,cassava,and rice,which generate a large amount of lignocellulosic agricultural wastes during agricultural as well as associated industrial processing.The efficient utilization of these wastes will have a significant impact on the economy and sustainable development of South China.This paper reviews the research investigations conducted both in China and elsewhere on the conversion of wastes from these subtropical or tropical agricultural crops into useful chemicals,energy,and biomaterials.The goal of this paper is to promote and summarize the extensive investigations on these agricultural wastes for the development of biorefinery.

Investigation and Improvement of Grass-roots Agricultural Extension System in Yichang City

Through a questionnaire survey, the working status, payment and ideological conditions of 166 grassroots agro-technicians were studied and analyzed. As is indicated by the results, the technicians are generally paid with low wages, and lack enthusiasm and initiative in jobs, and most of them take a second job. After an exposure of the existing problems in the grassroots agricultural extension system in Yichang, some suggestions were proposed for improving the agricultural extension system in the new era.

Machine Learning for Investigation on Endocrine-Disrupting Chemicals with Gestational Age and Delivery Time in a Longitudinal Cohort

Endocrine-disrupting chemicals(EDCs)are widespread environmental chemicals that are often considered as risk factors with weak activity on the hormone-dependent process of pregnancy.However,the adverse effects of EDCs in the body of pregnant women were underestimated.The interaction between dynamic concentration of EDCs and endogenous hormones(EHs)on gestational age and delivery time remains unclear.To define a temporal interaction between the EDCs and EHs during pregnancy,comprehensive,unbiased,and quantitative analyses of 33 EDCs and 14 EHs were performed for a longitudinal cohort with 2317 pregnant women.We developed a machine learning model with the dynamic concentration information of EDCs and EHs to predict gestational age with high accuracy in the longitudinal cohort of pregnant women.The optimal combination of EHs and EDCs can identify when labor occurs(time to delivery within two and four weeks,AUROC of 0.82).Our results revealed that the bisphenols and phthalates are more potent than partial EHs for gestational age or delivery time.This study represents the use of machine learning methods for quantitative analysis of pregnancy-related EDCs and EHs for understanding the EDCs’mixture effect on pregnancy with potential clinical utilities.

Evaluating the Effects of Sustainable Chemical and Organic Fertilizers with Water Saving Practice on Corn Production and Soil Characteristics

The rapidly growing world population,water shortage,and food security are promising problems for sustainable agriculture.Farmers adopt higher irrigation and fertilizer applications to increase crop production resulting in environmental pollution.This study aimed to identify the long-term effects of intelligent water and fertilizers used in corn yield and soil nutrient status.A series of field experiments were conducted for six years with treatments as:farmer accustomed to fertilization used as control(CON),fertilizer decrement(KF),fertilizer decrement+watersaving irrigation(BMP1);combined application of organic and inorganic fertilizer+water-saving irrigation(BMP2),and combined application of controlled-release fertilizer(BMP3).A significant improvement was observed in soil organic matter(14.9%),nitrate nitrogen(106.7%),total phosphorus(23.9%),available phosphorus(26.2%),straw yield(44.8%),and grain yield(54.7%)with BMP2 treatment as compared to CON.The study concludes that integrating chemical and organic fertilizers with water-saving irrigation(BMP2)is a good approach to increasing corn productivity,ensuring water safety and improving soil health.The limitations of the current study include the identification of fertilizer type and its optimum dose,irrigation water type,and geographical position.

Machine Learning for Investigation on Endocrine-Disrupting Chemicals with Gestational Age and Delivery Time in a Longitudinal Cohort

Endocrine-disrupting chemicals(EDCs)are widespread environmental chemicals that are often considered as risk factors with weak activity on the hormone-dependent process of pregnancy.However,the adverse effects of EDCs in the body of pregnant women were underestimated.The interaction between dynamic concentration of EDCs and endogenous hormones(EHs)on gestational age and delivery time remains unclear.To define a temporal interaction between the EDCs and EHs during pregnancy,comprehensive,unbiased,and quantitative analyses of 33 EDCs and 14 EHs were performed for a longitudinal cohort with 2317 pregnant women.We developed a machine learning model with the dynamic concentration information of EDCs and EHs to predict gestational age with high accuracy in the longitudinal cohort of pregnant women.The optimal combination of EHs and EDCs can identify when labor occurs(time to delivery within two and four weeks,AUROC of 0.82).Our results revealed that the bisphenols and phthalates are more potent than partial EHs for gestational age or delivery time.This study represents the use of machine learning methods for quantitative analysis of pregnancy-related EDCs and EHs for understanding the EDCs’mixture effect on pregnancy with potential clinical utilities.

How United States Agricultural Herbicides Became Military and Environmental Chemical Weapons: Historical and Residual Effects

Discoveries in Charles Darwin’s laboratory led to modern herbicides. Darwin discovered the internal mechanism that directed plants to grow toward sunlight and sources of water. Scientists in Europe and America later called this mechanism a plant’s hormone response system. Administrators and scientists, including Dr. Ezra J. Kraus, the Head of the Botany Department at the University of Chicago and a plant physiologist, suggested on the eve of WWII that weed killers had significant military value as chemical weapons. Dr. Kraus obtained access to a synthetic chemical, 2,4-D, and found that when the chemical was absorbed through the leaves of plants, it destroyed a plant’s hormones. After exposure, the plant experienced rapid and uncontrolled growth, and then the leaves shriveled, died and fell off. Dr. Kraus obtained funding for his Department of Botany research program from Department of Defense (DOD) during World War II (WWII). Camp Detrick (Biological Weapons Laboratory) scientists later obtained samples of newly created 2,4,5-T which contained unknown amounts of the by-product dioxin TCDD. In the 1950s and 1960s, Fort Detrick military scientists formulated the herbicide Agent Orange, which was a 50 - 50 mixture of 2,4-D and 2,4,5-T. These dual purpose herbicides were used by DOD and USDA. American and European farmers in the 1940s used 2,4-D and 2,4,5-T to eliminate weeds from pastureland and cropland. After WWII, synthetic herbicides (and pesticides) development continued in tandem with production of synthetic fertilizers and breeding of high-yield plant varieties. These new agricultural products were then shipped worldwide to increase crop yields, as part of the Green Revolution. This new system of agricultural technologies was intended to eliminate global starvation and increase food security by increasing field and farm crop yields. In contrast, the goal of military use of herbicides, as chemical weapons, was to defoliate jungle forests and destroy food crops as a strategy to win battles and wars. The primary objective of this research study is to describe how agricultural herbicides became tactical chemical weapons. A current assessment will address the environmental impacts of military and environmental chemical weapons on the United States and Vietnam ecosystems and need for additional dioxin TCDD hotspot clean-up efforts.

INVESTIGATION OF CHEMICAL CONSTITUENT FROM CELASTRUS ANGULATUS

Three new β-dihydroagarofuran sesquiterpene polyol esters,one alkaloid and two non-alkaloids,were isolated from the MeOH extract of seed oil of Celastrus angulatus. Their structures were elucidated on the basis of UV,IR,mass,NOE difference,~1H-NMR,^(13)C- NMR and ~1H-^(13)C long-range correlation spectroscopy.

QUALITY CONTROL OF TRADITIONAL CHINESE MEDICINES: INVESTIGATION ON CHEMICAL MARKERS

Traditional Chinese medicines(TCMs)have played an important role in the treatment of diseases for thousands of years.With the rise of the combination therapy for multi-gene diseases,TCMs attracted more attentions gradually.However,TCMs is a complex system which could contain tens,or even hundreds of compounds.Selection of chemical markers is thus a key to the

Environmental Impact Assessment of Cotton Ginning Agricultural Machinery

This paper realizes the hazards of chromium contamination and pollution caused in the use of chrome composite leather-clad(CCLC)rollers commonly used in cotton roller ginning industries and attempts to eliminate the chromium contamination and pollution during this environmental impact assessment(EIA)process.The cotton roller ginning process is the mechanical separation of cotton fibres from their seeds by means of one or more rollers to which fibres adhere while the seeds are impeded and struck off or pulled loose.Most of the cotton ginning operations are done using roller gins.The CCLC roller coverings contain about 18,000 to 30,000 mg/kg(ppm)as total chromium of trivalent and hexavalent forms which are toxic to human health.When the seed-cotton is ginned,due to the persistent rubbing of CCLC rollers over the fixed knives,the cotton and its products get contaminated with the total chromium of trivalent and hexavalent forms.Gin mill workers are exposed to the cotton dust and chromium pollution and are susceptible to health hazards such as premature death,cancer,byssinosis,and ulcers in cotton ginning air environment since toxic effects are produced by prolonged contact with airborne or solid or liquid chromium compounds even in small quantities.Noise pollution of agricultural ginning machinery in seed-cotton ginning mills has been found out to be 102-103 dB(A)decibel levels.To offset this problem,pollution-free rubberized cotton fabric(RCF)eco-friendly rollers for both the laboratory and commercial studies have been designed,fabricated and used in experiments in rollers gins.This nullifies chromium contamination and pollution during the complete process.Cotton technological parameters are well proven for commercial acceptance.

西安市涉农产品检测机构建设调研

随着人民群众对农产品品质要求的提升,农产品质量安全检测机构的建设越来越受重视。为全面准确地认识和把握西安市农产品质量安全检验监测中心在全市涉农产品检测机构中的功能和职责定位,充分发挥其在全市农产品质量安全工作中的保障作用,采用现场座谈和问卷调查相结合的方式,对西安市域内省级、市级和第三方涉农产品检测机构的建设现状进行了调研。在此基础上,针对性地提出了西安市农检中心发展建设的对策和建议:紧密围绕主导产业检测需求,充分发挥检测机构实验室效能;依托全国名特优新农产品营养品质鉴定机构平台,促进西安市特色果品产业做大做强;以全面推广农产品全程质量控制技术为抓手,持续提高农业产前、产中、产后全过程服务水平。

农地流转的碳减排效应研究

农地流转可以促进农地的集中使用和规模化经营,会降低农业生产经营过程中的化学品和机械等生产性投入强度,并促进农作物种植结构“趋粮化”,进而降低农业碳排放强度。采用2011—2021年30个省份的数据检验农地流转率对农业碳排放强度的影响,结果表明:农地流转率提高对农业碳排放强度具有显著的负向影响;农地流转能够通过减少农业化学品和机械投入强度、提高粮食种植面积占比来降低农业碳排放强度。进一步分析发现,因流转对象和形式的不同,农地流转的碳减排效应存在异质性,表现为:相比流入农户、企业的农地流转,流入合作社的农地流转具有更为显著的碳减排效应;相比采用出租转包、互换转让形式的农地流转,采用股份合作形式的农地流转具有更为显著的碳减排效应。因此,应积极推动农地有序流转,不断完善农地流转机制,合理引导农地流转方向,并鼓励农地流转与农业碳减排项目相结合,以有效减少农业碳排放。

“双碳”目标下农业废弃物资源化实施新路径

“碳达峰”和“碳中和”是我国的重大国家战略,作为第一产业的农业在这一战略目标的实现过程中发挥着至关重要的作用。而农业领域“双碳”目标的推进中农业废弃物的资源化又是重要的一环。本文阐述了农业废弃物除传统的“五料化”利用技术之外的几种资源化新路径,包括将农业废弃物定向转化为高附加值化学品和液体燃料、农业废弃物制备生物炭及其他功能化碳材料、农业废弃物制备可燃气以及农业废弃物制备生物质基可降解塑料等,并简要提出了这些农业废弃物资源化新路径需要进一步提升的问题及在实施过程中如何实现最大程度的碳减排,从而最大程度地促进农业领域“双碳”战略目标的实现。

习仲勋长葛调查若干史事的考订和辨正

1961年4月,习仲勋赴河南长葛农村蹲点调查,核心任务是讨论和修改“农业六十条”。学界对这次调查的研究尚存一些史事疑点和舛误。本文进一步澄清和明确了习仲勋进驻长葛的时间是4月10日,离开的时间在5月12日至16日之间。习仲勋在长葛倡导的“包总产”是指生产队承包生产大队的产量和工分等,与当时全国一些地区的“包产到户”是两种不同的生产责任制度。他积极试验包产到户的说法,现有证据不足以支持。习仲勋长葛调查期间提出的“社会主义的初级阶段”与毛泽东的“不发达的社会主义”基本精神一致,与改革开放后出现的“社会主义初级阶段”概念有较大区别。

现代林产化学加工技术的现状与发展趋势

生物质资源来源广泛,具有可再生性、结构多样性和碳中性等特点。目前,以生物质为原料的林产化工已成为继煤和石油化工之后最重要的化工产业之一。在对中国的林产化学工业发展历史概览的基础上,梳理总结了现代林产化学工业的发展,创新地提出了林产化学加工工程学科发展的能源化、材料化、食药化、饲料化、肥料化和基料化6个方向。其中,能源化中的生物质气/液/固体燃料的有效开发是实现碳达峰和碳中和的重要途径之一,而我国林产化工的传统研究领域制浆造纸、木本油脂、松脂化学等则从材料化找到新的突破和发展,相比前两者,食药化、饲料化、肥料化和基料化还有很大的发展空间。林产化学工业已迈入质量和效益持续提升发展新阶段,今后将在生物质资源高值化利用、全质利用技术创新、精深加工与应用、绿色低碳与生物技术融合、生物基材料与化学品创新应用,以及多学科交叉融合等方面实现突破,推动产业转型升级,构建绿色低碳循环发展新模式。

中国农业减污降碳协同效应及其影响机制研究

农业面源污染与农业碳排放是中国农业面临的重要环境问题。现有研究忽视了农业面源污染治理与农业碳减排之间的协同关系,未探索农业减污降碳协同效应及其影响机制,影响农业可持续发展。为此,本文借鉴现有成果,提出农业减污降碳协同效应概念,基于2007—2021年中国30省份面板数据,利用双固定效应回归模型、调节效应模型对农业减污降碳协同效应及其影响机制进行实证分析,并讨论地区异质性。结果表明:1)农业减污降碳协同效应存在,农业面源污染与农业碳排放存在显著的协同关系,当农业面源污染减少时农业碳排放也将显著减少,该结果进行稳健性检验和处置内生性后依然成立;2)农业化学物资消费结构对农业减污降碳协同效应产生显著负向调节作用,农业化学物资使用效率与农业种植结构产生显著正向调节作用,农业投资规模产生负向调节作用但不显著;3)北方地区农业减污降碳协同效应比南方地区更为显著,农业化学物资消费结构与农业化学物资使用效率对北方地区农业减污降碳协同效应产生显著负向调节作用,农业种植结构对北方地区和南方地区农业减污降碳协同效应产生显著正向调节作用。因此,农业降污减碳协同效应存在。