The occurrence characteristics of oil in shales matrix from organic geochemical screening data and pore structure properties:An experimental study Author links open overlay panel

The occurrence characteristics of shale oil are of great significance to the movability of shale oil.In this study,the occurrence characteristics of oil in the shale matrix at Funing Formation shale in Subei Basin were quantitatively evaluated by organic geochemistry and microscopic pore structure characterization experiments.The Multiple Isothermal Stages Pyrolysis(MIS)experiment results show that the content of total oil,adsorbed oil,and free oil in the shales are 3.15-11.25 mg/g,1.41-4.95 mg/g,and 1.74-6.51 mg/g,respectively.among which the silicon-rich shale has the best oil-bearing.The relative content of free oil shows an increasing trend in pores with pore diameters greater than 3 nm.When the relative content of free oil reaches 100%,the pore size of silicon-rich shale is about 200 nm,while that of calcium-rich shale,clay-rich shale,and siliceous mixed shale is about 10 nm.The occurrence law of adsorbed oil is opposite to that of free oil,which indicates that shale oil will occur in the pores and fractures in a free state in a more extensive pore size range(>200 nm).This study also enables us to further understand the occurrence characteristics of shale oil under the interaction of occurrence state and occurrence space.

Prediction and driving factors of forest fire occurrence in Jilin Province,China

Forest fires are natural disasters that can occur suddenly and can be very damaging,burning thousands of square kilometers.Prevention is better than suppression and prediction models of forest fire occurrence have developed from the logistic regression model,the geographical weighted logistic regression model,the Lasso regression model,the random forest model,and the support vector machine model based on historical forest fire data from 2000 to 2019 in Jilin Province.The models,along with a distribution map are presented in this paper to provide a theoretical basis for forest fire management in this area.Existing studies show that the prediction accuracies of the two machine learning models are higher than those of the three generalized linear regression models.The accuracies of the random forest model,the support vector machine model,geographical weighted logistic regression model,the Lasso regression model,and logistic model were 88.7%,87.7%,86.0%,85.0%and 84.6%,respectively.Weather is the main factor affecting forest fires,while the impacts of topography factors,human and social-economic factors on fire occurrence were similar.

The occurrence phases and enrichment mechanism of rare earth elements in cobalt-rich crusts from Marcus-Wake Seamounts

To explore the occurrence phases and enrichment mechanism of rare earth elements(REEs)in cobalt-rich crusts,this study analyzes the mineral composition and REE contents of the samples from Marcus-Wake Seamounts by XRD,ICP-OES and ICP-MS.The results show that,(1)the cobalt-rich crusts contain the major crystalline mineral(vernadite),the secondary minerals(quartz,plagioclase and carbonate fluorapatite),and a large amount of amorphous ferric oxyhydroxides(FeOOH).(2)The cobalt-rich crusts contains higher Mn(10.83%to 28.76%)and Fe(6.14%to 18.86%)relative to other elements,and are enriched in REEs,with total REE contents of 1563−3238μg/g and Ce contents of 790−1722μg/g.Rare earth element contents of the old crusts are higher than those of the new crusts.Moreover,the non-phosphatized crusts have positive Ce and negative Y anomalies,and yet the phosphatized crusts have positive Ce and positive Y anomalies,indicating that cobalt-rich crusts is hydrogenetic and REEs mainly come from seawater.(3)Analytical data also show that the occurrence phases of elements in cobalt-rich crusts are closely related to their mineral phases.In the non-phosphatized crusts,REEs are adsorbed by colloidal particles into the crusts(about 67%of REEs in the Fe oxide phase,and about 17%of REEs in the Mn oxide phase).In contrast,in the phosphatized crusts(affected by the phosphatization),REEs may combine with phosphate to form rare earth phosphate minerals,and about 64%of REEs are enriched in the residual phase containing carbonate fluorapatite,but correspondingly the influence of Fe and Mn oxide phases on REEs enrichment is greatly reduced.In addition,the oxidizing environment of seawater,high marine productivity,phosphatization,and slow growth rate can promote the REE enrichment.This study provides a reference for the metallogenesis of cobalt-rich crusts in the Pacific.

Occurrence and Control of Main Pest Groups in Allium tuberosum Fields in Shijiazhuang

[Objectives]This study was conducted to investigate the species and occurrence patterns of main pests in the Chinese chive(Allium tuberosum)fields in Shijiazhuang.[Methods]Our research group conducted a systematic investigation on the types and occurrence of major pests in Chinese chive fields in Shijiazhuang from April 2019 to November 2020 using the Malaise net method.[Results]The main pests harming Chinese chives in the region included Thrips tabaci,Bradysia odoriphaga,Luperomorpha suturalis,Acrolepla alliella,Liriomyza chinensis,and Neotoxoptera formosana.The pest populations in the region mainly experienced two peak periods,from mid June to mid July and from late August to late September.Meanwhile,corresponding green prevention and control measures were proposed based on the occurrence characteristics and biological characteristics of different pests in local chive fields.[Conclusions]Predicting the occurrence of pests in Chinese chive fields can provide basis for farmers to take timely prevention and control measures,reduce the damage of pests in the field to Chinese chives and realize high-quality production of Chinese chive.

Occurrence Regularity and Comprehensive Prevention and Control Techniques of Sunflower Downy Mildew

This paper examines the occurrence regularity and comprehensive prevention and control techniques for sunflower downy mildew.It provides a detailed discussion of the pathogens,symptoms,and associated risks,as well as the transmission pathways,underlying causes,and prevention and control techniques related to sunflower downy mildew.The aim is to offer valuable references and technical guidance for the effective management of this disease.

Gold occurrence of Jiaojia gold mine in Shandong province

The microscopy and scanning electronic microscopy （SEM） were used to study the gold occurrence of Jiaojia gold mine, Shandong province. The results show that the gold-bearing minerals are composed of pyrite, chalcopyrite, gangue, sphalerite and galena. 77.12% of gold minerals are the sulphides and 22.88% are the gangues. The gold occurrence is composed of 60.28% fissure gold, 21.63% inclusion gold and 18.09% crystal fractured gold. The morphology of gold mineral is composed of sphere, triangle, rectangle, strip and erose. The Jiaojia gold mineral owns large grain size range from 3-5 μm to 100 μm. 1.5% of gold grains is more than 0.104 mm, 5.26% is 0.074-0.104 mm, 23.31% is 0.043-0.074 mm, 3.76% is 0.043-0.037 mm and 64.29% is less than 0.037 mm. The occurrence of gold mineral is composed of native gold, electrum, native silver, iron-bearing native silver, goldcuprid and acanthite. Electrum is the most important mineral, accounting for 71.56%. The average quality is 641.26‰ for gold and silver mineral.

Law of Occurrence and the Damage of Main Diseases and Pests in Ligusticum chuanxiong Hort Field

[Objective]The aim was to provide scientific basis for the prevention and treatment of the main diseases and pests. [Method]The systematic investigation was carried out in the process of seedling and field cultivation of Ligusticum chuanxiong. [Result]The main diseases were root rot,Powdery mildew and Spot blight,while the main pests were Epinotia leucantha Meyrick,Prodenia litura Fabr.,Scarabaeoidea,Tetranychus cinnabarinus Boisduval and Delia platura Meigen. [Conclusion]The law of occurrence of main diseases and pests were confirmed.

Reasearch on Occurrence Rules of Asian Corn Borer Ostrinia furnacalis in the Field of Waxy Corn

[Objective] This program aimed at providing basis for timely and effective control of Asian corn borer Ostrinia furnacalis in waxy corn fields through investigations and researching on occurrence and damage characteristics of Ostrinia furnacalis in the main producing area of waxy corn of Shanxi Province.[Method] Attraction and collection of the adults,fixed-points and random investigations on eggs and larvae were the main methods in this research.[Result] Ostrinia furnacalis appeared in two generations per year in the field of waxy corns,the generations were basically nonoverlapping with significant interval.The peak period of the overwintering generation adults in the field of waxy corn was early to middle of June,peak period of the first generation adults was from early August to late August;peak period of the first generation eggs was from the end of early June to the binning of late June,the peak period of the second generation eggs was from the middle of early August to late August.Egg-laying performances of Ostrinia furnacalis on waxy corns in different growth period suggested that the temptation of waxy corns to egg-laying of Ostrinia furnacalis had gradually increased with the continuation of growth stages before the heading of waxy corns;while after the heading of waxy corns,the temptation of waxy corns to egg-laying of Ostrinia furnacalis had gradually reduced with the continuation of growth stages.The amount of eggs on waxy corns was more than eggs on normal corns with the same growth period and growth conditions.The first generation of Ostrinia furnacalis caused more serious damages than the second generation.The first generation larvae caused more serious damages on waxy corns with early sowing period than with middle sowing period,while the late sowing fields basically uninjured.The early sowing and middle sowing corns were damaged but lightly,due to the slight occurrence of the first generation larvae.The second generation larvae caused more serious damages in late sowing waxy corn field than in middle sowing waxy corn field.As the early sowing waxy corns were harvested before the beginning of damage peak period of the second generation larvae,they were basically uninjured or slightly damaged by the second generation larvae in general years.Because the second generation larvae were in large-scale occurrence,they had caused serious damages to late and later middle sowing waxy corns.Incidence of ear rot disease on the female ears of waxy corns was closely related to the damages of Ostrinia furnacalis on ears,which was higher on the ears infested by Ostrinia furnacalis.[Conclusion] Comprehensive control on the second generation of Ostrinia furnacalis in the mid and late sowing field of waxy corn should be strengthened.

Occurrence Regularity and Control Research of Apple Early Defoliation Disease in West Sichuan Plateau

[ Objective ] The research aimed to discuss the occurrence regularity of apple early defoliation disease and control effects of fungicides in west Sichuan plateau. [ Method ] Apple early defoliation disease in west Sichuan plateau was systematically investigated during 2009 and 2011, and the control effects of different fungicides during different spraying periods were studied. [ Result] The species of pathogen mainly was Marssonina ma/i （ P. Henn）, accounting for 32.5%, Phyl-losticta Pirina Sa accounted for 29.9%, and Alternaria mali Roberts accounted for 25.7%. The field fluctuation regularity was as follows ： the disease generally be- gan in the mid-May and ended in early and middle October with only one damage peak during the whole year, the fluctuation had positive correlation with rainfall （ R2 =0.891 8 ＊ ＊ ）. Control test showed that 40% flusilazole had the best control effect （86.5%）, which was best to apply after anthesis. [ Conclusion ] The paper provided theoretical basis for the effective control against apple early defoliation disease.

Research Progress of Occurrence and Comprehensive Control of Oriental Fruit Fly [Bactrocera dorsalis (Hendel)]

The paper summarizes the research progress of occurrence and comprehensive control of oriental fruit fly in the following aspects ： biological and ecological characteristics, assessment of the risk and suitability, dynamic monitoring and control index, and comprehensive control methods.

Study on the Occurrence and Epidemic Regularity and Region Division of Rice Blast in Nanchong City

With the aim to improve the level of monitoring and warning as well as the comprehensive control of rice blast disease, and to feasibly reduce the disease threat in Nanchong City, the methods of GPS and GIS, systematical monitoring and field survey, rice blast resistance identification, physiologic races of rice blast monitoring, and meteorological data analysis were performed to study the occurrence and epidemic region division, precise demarcation and occurrence and epidemic regularity of rice blast in Nanchong City. This study first completed the epidemic region division and precise demarcation; first clarified the initial affection（beginning period） locations, occurrence characteristics, epidemic trends and characteristics; explicated the existence of four epidemic peak periods of rice blast in the field, where the damage areas of first peak period played a decisive role during the blast epidemic years; in late May, the cumulative occurrence areas and annual occurrence areas presented higher positive correlation with the correlation coefficient of 0.817;and established a prediction model of occurrence areas per year based on the disease field rate at the end of boot stages and the diseased plant rate at dough stages. The results of investigation on the impact factors investigation of blast disease in Nanchong in recent years suggested that the internal causes were the decrease or loss of blast resistance of the rice cultivars, as well as the increase of physiological races with strong resistance to rice blast and the emergence of new virulent physiologic varieties; the external causes were suitable temperature, too much rainy, and sunlight shortage. Between 2010 and 2015, the short-term forecast accuracy for rice blast in Nanchong was up to 100%, and medium-and long-term forecast accuracy was also up to 98% and 95%, respectively, which increased by 5-15% than that before 1997, thereby making the control effect of rice blast in Nanchong increased by 15-30%.

Occurrence and Control of Tetranychus truncatus and T. urticae on Corns of Yanbian Area

The situation of occurrence and hazards by Tetranychus truncatus and T. urticae on corns in test garden of Agricultural College of Yanbian University were narrated in detail. The characteristics of distribution and damage by T. truncates and T. urticae, morphological characteristics, the rule of currencies and its relation- ship with environment were summarized, and the methods of comprehensive treat- ment were put out, which could effectively control the hazard degree of T. truncates and T. urticae on corns.

Synchronous and metachronous occurrence of gastric adenocarcinoma and gastric lymphoma: A review of the literature

The occurrence of both primary gastric lymphoma and gastric adenocarcinoma in the same patient is a rare entity. The possible causative factors of synchronous or metachronous occurrence of both malignancies and varieties in the treatment modalities are reviewed according to published cases in English language medical literature.

Species and Occurrence of Scarab in Sweet Potato Growing Areas of Xuzhou,Jiangsu

Frequency-vibrancy pest-killing lamp was used to calculate the numbers and types of scarabs during the growing period of sweet potato in Xuzhou area, thus to study the occurrence regularity of scarab and effect of meteorological factor on its occurrence, which provided a reference and guidance for the control of grub in sweet potato field. The monitoring results indicated that scarabs in sweet potato planting area of Xuzhou mainly included Anomala corpulenta, Holotrichia parallela Motschulsky, Maladera verticalis and Holotrichia trichophora Fairm. Holotrichia tri- chophora Fairm has entered into its late stage at the early cultivation stage of sweet potato with a few occurrence quantities. The elongation stage of sweet potato vine is the full incidence period of imagoes of Maladera verticalis and Anomala cor- pulenta. Full incidence period of Holotrichia parallela Motschulsky is from late June to middle August, the outbreak cycle of which is long. The unearthed imagoes fol- low the regular change ＂many-few-many-few＂. Effects of meteorological factor on the activities of various scarabs are different. The activities of various scarabs are fre- quent in warm and windless sunny days. In rainy days, Holotrichia parallela Motschulsky, Holotrichia trichophora Fairm and Maladera verticalis are inactive. The numbers of Anomala corpulenta in cloudy days but not rainy days are higher than that in sunny days.

Morphological Observation of Rhynhophorus ferrugineus Fabricius and Investigation on Its Occurrence and Damage

[Objective] The morphology observation and investigation on occurrence and damage condition of Rhynhophorus ferrugineus were conducted.[Method] The samples of R.ferrugineus at different instars were collected from the nurseries in Nanning City,and morphological observation was carried out under the entity microscope,and their characteristics were described.In Nanning City,with Palm plants as the investigation object,the random sampling investigation was conducted in damage peak period of R.ferrugineus,the total number of investigated plants and the number of damaged plants was recorded.[Result] The size,shape and arrangement of droplet-shaped spots in adult pronotum of different individuals of R.ferrugineus are inconsistent,the morphological characteristics of larvae in different host are the same,while the sizes of insect bodies of the same instar are different.The pests mainly distribute in part of nurseries and the concentrated cultivation places of palm trees in Nanning City,which mainly damage the palm plants such as R.rivularis,W.filifera,P.canariensis,B.nobilis and P.x loureirii,etc.within Nanning City.[Conclusion] The study laid the foundation for the research on the occurrence law and the control technique of R.ferrugineus in Nanning City.

Variability of Tropical Cyclone in High Frequent Occurrence Regions over the Western North Pacific

In this study, three high frequent occurrence regions of tropical cyclones(TCs), i.e., the northern South China Sea(the region S), the south Philippine Sea(the region P) and the region east of Taiwan Island(the region E), are defined with frequency of TC's occurrence at each grid for a 45-year period(1965–2009), where the frequency of occurrence(FO) of TCs is triple the mean value of the whole western North Pacific. Over the region S, there are decreasing trends in the FO of TCs, the number of TCs' tracks going though this region and the number of TCs' genesis in this region. Over the region P, the FO and tracks demonstrate decadal variation with periods of 10–12 year, while over the region E, a significant 4–5 years' oscillation appears in both FO and tracks. It is demonstrated that the differences of TCs' variation in these three different regions are mainly caused by the variation of the Western Pacific Subtropical High(WPSH) at different time scales. The westward shift of WPSH is responsible for the northwesterly anomaly over the region S which inhibits westward TC movement into the region S. On the decadal timescale, the WPSH stretches northwestward because of the anomalous anticyclone over the northwestern part of the region P, and steers more TCs reaching the region P in the greater FO years of the region P. The retreating of the WPSH on the interannual time scale is the main reason for the FO's oscillation over the region E.

Occurrence and Damage of Maize Gray Leaf Spot and Its GPS Monitoring

Maize gray leaf spot is a kind of leaf disease seriously threatened the production of maize,which occurs all around the world.The occurrence and damage conditions of maize gray leaf spot at home and abroad and in Yunnan Province are described,the latest research process of maize gray leaf spot are summarized,and the integrated control methods of maize gray leaf spot and its GPS monitoring are further introduced.

Effect of Climate Change on Cotton Lugus lucorum Occurrence Degree

[Objective] The aim was to analyze effect of climate change on occurrence degree of cotton Lugus lucorum in coastal areas of Jiangsu Province, in order to provide authentic references for better prevention. [Method] Statistical analysis was conducted on Information about occurrence degree of cotton Lugus lucorum in Binhai County in Jiangsu Province from 1985 to 2007 under guidance of Integral regression method. [Result] Because of climate change, cotton Lugus lucorum occurrence de- grees differed in different generations and growth stages in Binhai County. Tempera- ture and humidity constituted the main climate factors. In general, climate change hindered occurrence degree from increasing. We could make use of the period when occurrence degree of cotton Lugus lucorum is prone to significant increase and choose some periods, such as early April, late June and middle August, to improve prevention effect. In addition, attention should be paid to comprehensive measures, such as adjustment of industrial structure, which will reduce pesticide and minimize cotton Lugus lucorum damage and adverse impact from prevention measures. [Conclusion] The results provided authentic references for cotton Lugus lucorum preven- tion in Jiangsu coastal areas.

Occurrence and Control of Pear Blight Rot(Phytophthora cactorum) in Qianxian of Shaanxi Province

[ Objective ] The paper was to investigate the occurrence condition of pear blight rot in pear-producing areas in Qianxian of Shannxi Province, so as to find the main cause of the disease and the effective agents for the disease. [Method] The occurrence condition of pear blight rot was surveyed in field, the inci- dence rate of trees and incidence index of fruits were counted, and the field control test of different agents against pear blight rot was carried out. [ Result] The ma- jor reasons for outbreak of pear blight rot in Ganhe pear-producing areas in Qianxian of Shannxi Province were excessive rainfall and high temperature and humidity in July 2010, poor drainage in orchards and large planting density were also the main factors causing outbreak of pear blight rot. 64% oxadixyl · mancozeb WP, 60% metalaxyl-mancozeb WP and 80% aliette WP had significant control effect on pear blight rot, fruit bagging was also an ideal measure for prevention of the dis- ease. [ Conclusion] Pear production should focus on improving the air and light condition, enhancing the drainage capacity of orchard and promoting bagging culti- vation, and the systemic control agents should be selected to control pear blight rot.

Occurrence Regulation and Control Measure Comparison of Rice Sheath Blight

Rice sheath blight is widely distributed throughout the world, it can cause damage on many kinds of crops. Pathogen characteristics, infection cycle, occurrence law, damage law and different control methods of rice sheath blight in China are summarized, which will provide foundation for further worldwide research on the disease.