72results about How to "Inhibition of poisoning" patented technology

The invention relates to a low-temperature smoke denitration SCR (silicon controlled rectifier) catalyst, which comprises a carrier, a manganese oxide, and composite oxide of one or more of Ce, Zr, Ti, Co, Fe and Cu, the mass content of manganese is 0.1-66 percent, and the total mass content of the Ce, Zr, Ti, Co, Fe or / and Cu is 0-50 percent; and glass fiber and / or kieselguhr is used as the carrier, wherein the glass fiber of the carrier is calcined for 2-4 hours at temperature of 400-600 DEG C, then placed in a nitric acid, sulfuric acid or hydrochloric acid solution with mass concentration of 5-40 percent for acidizing for 1-8 hours, washed by distilled water to be neutered, dried at temperature of 80-120 DEG C, and crushed to have the fineness of 20-325 meshes. The catalyst uses the glass fiber and the kieselguhr as the carriers, so that the dispersion effect of nanoparticles and specific surface area of the catalyst are increased, the high adsorptive capacity and strong heat resistance and corrosion resistance capacity are achieved, stronger toxic resistance capacity to sulfur dioxide and stream contained in the smoke is realized, the invention can be used for 10-200 DEG C of low temperature smoke denitration, and has strong water resisting and sulphur toxic resisting capacities.

The invention discloses application of dihydromyricetin in preparing a medicine for preventing and treating untoward reactions in radiotherapy and chemotherapy of tumor. In particular, the application is to prepare medicines for preventing and treating untoward reactions in radiotherapy and chemotherapy of tumor, preventing and treating arrest of bone marrow and baldness, resisting mutation, preventing and treating the generation of secondary tumors, preventing and treating tumor transfer, and preventing and treating breast cancer, cervical carcinoma, intestinal cancer and the like. The invention creatively finds that the dihydromyricetin has the effects of removing free radicals, inhibiting reaction chains of the free radicals, resisting the mutation, inhibiting the expression of the tumor gene, causing the death of tumor cells, preventing and treating the tumor generation, preventing and treating the secondary tumors and the transfer of the secondary tumors and preventing and treating infection. Therefore, as the medicine for preventing and treating untoward reactions in radiotherapy and chemotherapy of tumor, the dihydromyricetin can inhibit and alleviate chemical damage, prevent and treat damage of a mutagen and further prevent gene mutation or the secondary tumors; and by combination with the radiotherapy and chemotherapy, the effects of preventing untoward reactions in radiotherapy and chemotherapy of tumor and preventing generation of tumors are achieved.

The invention discloses a method for inhibiting low-temperature denitration catalyst poisoning caused by SO2. A NO oxidation device is arranged at a flue gas inlet of a selective catalytic reduction (SCR) denitration facility, 5-70% of NO in flue gas is oxidized into NO2 by the NO oxidation device, the flue gas containing NO2 is fed into the SCR denitration facility at a space velocity of 1000-200000h<-1> and the flue gas is subjected to denitration purification at a temperature of 50-300 DEG C. Through a reaction of NO2 obtained by oxidation of NO and an ammonium salt deposited on the surface of the low-temperature denitration catalyst, the method can effectively inhibit SO2-ammonia gas reaction-caused deposition of ammonium salts such as ammonium sulfate and ammonium sulfite on the surface of the low-temperature denitration catalyst thereby inhibiting SO2-caused low-temperature SCR denitration catalyst poisoning so that a service life of the low-temperature denitration catalyst is prolonged and a SCR denitration operation cost is reduced.

Disclosed is a nanometer fuel oil addition agent, wherein the constituents comprises (by weight percent): rare earth powder 0.1-10%, fuel synergistic agent 1-10%, dispersing agent 1-20%, oleinic acid 1-10%, castor oil 1-20%, and balancing white oil.

The invention provides a thin-film getter with high gas absorption performance and a preparation method thereof. The thin-film getter is formed by depositing a gas absorbing layer on a metal, silicon, ceramic or glass substrate or on the inner wall of a sealed device or is a film with two-layer structure composed by the gas absorbing layer and an adjusting layer, wherein the gas absorbing layer is multi-component alloy formed by Zr, Co and at least one material selected from the group consisting of Y, La, Ce, Pr and Nd, and the adjusting layer is one or alloy of more selected from the group consisting of Ti, Zr, Y, Hf, Mn, Cu, Cr, Al, Fe, Pt and Ru. The preparation method employs radio frequency magnetron sputtering for deposition of films of the gas absorbing layer and the adjusting layer. The thin-film getter provided by the invention is activated at a temperature in a range of 250 to 350 DEG C, has a high gas absorption rate and high gas absorption capacity, overcomes the problems of poor adhesion, low preparation efficiency and easy poisoning during activation of conventional thin-film getters and can meet design requirements for a vacuum working environment needed for realizing high reliability and a long service life of micro-electromechanical systems (MEMS), flat-panel displays (OLED / FED / LCD), solar heat-insulating boards and hydrogen-sensitive microelectronic devices.

The present invention discloses a Na2Fe2(SO4)3 / graphene composite positive electrode material for a sodium ion battery. The Na2Fe2(SO4)3 / graphene composite positive electrode material comprises graphene having a three-dimensional structure, wherein Na2Fe2(SO4)3 is compounded on the graphene surface in an in-situ compounding manner. The invention further discloses a preparation method of the composite positive electrode material. The preparation method comprises: dispersing graphene oxide, a sodium source, a sulfur source and a ferrous salt in water to obtain a suspension, carrying out a hydrothermal reaction on the obtained suspension at a temperature of 90-140 DEG C, carrying out solid-liquid separation on the hydrothermal reaction product, carrying out liquid nitrogen quenching, and drying to obtain a precursor; and carrying out calcination treatment on the precursor to obtain the composite positive electrode material. According to the present invention, the active substance and the carbon substrate are tightly bound, the coating is good, and the good physical and chemical properties are provided; the synthesis method is simple, the condition is mild, and the yield is high; the active substance is uniformly dispersed in the prepared composite material; and with the application of the prepared composite material as the sodium ion positive electrode material, the advantages of high specific capacity, high working voltage, good cycle stability and excellent rate performance are provided.

The invention relates to a low-temperature SCR catalyst prepared by extrusion molding, and a preparation method thereof. The invention belongs to the field of atmosphere pollution controlling. According to the invention, an extrusion molding method is adopted for preparing the catalyst, and the technology is skillfully designed. The activity, sulfur dioxide resistance and water intoxication resistance of the prepared catalyst satisfy application requirements. The activity, the sulfur dioxide resistance and the water intoxication resistance of the catalyst are maintained, and a certain mechanical strength is ensured in the catalyst particles.

The invention discloses a novel organic coated core-shell nano composite hydrogen storage material and a preparation method thereof. The preparation method comprises the steps that magnesium blocks, nickel powder and lanthanum powder are selected and proportioned, the weighed magnesium blocks are heated to 750-800 DEG C under the protection of the SF6-CO2 mixed atmosphere, pre-pressed nickel-lanthanum sheets are put into molten magnesium, an alloy melt is continuously heated, heat preservation is carried out, casting in a steel mold preheated to 200 DEG C in advance is carried out after all the nickel-lanthanum sheets are molten, air cooling is carried out to reach the room temperature, obtained magnesium-rich alloy ingots are placed in an argon-shielding closed ball milling tank for grainrefinement, obtained nano / amorphous alloy powder, CNTs and TiF3 are added into a ball milling tank, high-energy ball milling is carried out under the protection of high-purity argon so as to obtain nano composite hydrogen storage alloy powder, and PMMA ultrasonic is added so as to obtain the three-layer core-shell type nano composite hydrogen storage material. According to the novel organic coated core-shell nano composite hydrogen storage material and the preparation method thereof, the activation and circulation characteristics of an magnesium-rich alloy are obviously improved, and the goodmodification effects after tissue regulation and control and surface catalysis are consolidated.

The invention relates to an electrochemical CO gas sensor which comprises a shell (6), a porous film (7), a reference electrode (1), a working electrode (2) and an auxiliary electrode (3). The reference electrode (1), the working electrode (2) and the auxiliary electrode (3) are encapsulated in the shell (6). The electrochemical CO gas sensor is characterized in that a composite catalyst film (5)is coated on the working electrode (2), hydrogel (4) is simultaneously coated on the reference electrode (1), the auxiliary electrode (3) and the composite catalyst film (5) which is formed by mixinga mixed catalyst and N-octyl pyridinium hexafluorophosphate in a mass ratio of 1-20 to 1, the mixed catalyst is formed by mixing nano Pt / carbon nanotubes and nano nickel / carbon nanotubes in a mass ratio of 10-40 to 1, and the hydrogel is gel formed in a way that superabsorbent absorbs water which contains dissolved lithium perchlorate and polyvinyl alcohol. The sensor is watertight and has the service life of 3-5 years and stable performance, and the decorative film on the working electrode is replaceable.

The invention discloses a catalyst for purifying nitric oxide, and a preparation method of the catalyst. The catalyst comprises a bauxite carrier and one or more active ingredient(s) in transition metal ions such as Cu, Co and Mn or little precious metals such as Pt, Rh and Pd which is / are loaded on the bauxite carrier, wherein the weight of the active ingredient(s) is 1-10% of the total weight of the catalyst. The catalyst adopts one or more in alkali metals such as Li, Na, K and Rb or alkaline-earth metals such as Mg, Ca, Ba and Sr as accessory ingredient, and the weight of the alkali metal(s) and the alkaline-earth metal(s) is 10-30% of the total weight of the catalyst. The purification effect and the service life of the catalyst are superior to those of the traditional Pt / Ba / Al2O3 catalyst; and the catalyst is convenient to operate, low in cost and good in purification effect, and has obvious industrial application value.

The invention relates to the technical field of soil remediation, in particular to a soil conditioner as well as a preparation method and use method thereof. The soil conditioner comprises the following components in percentage by weight: 40-60% of copper tailings, 20-40% of fluorite tailings or limestone, 6-20% of talc, serpentine or dolomite, and 2-5% of a pellet curing agent, wherein the totalweight is 100%; and the copper tailings include quartz, alunite and dickite. The preparation method comprises the following steps: step 1, weighing the components and mixing the components uniformly;sep 2, preparing the mixture obtained in the step 1 into pellets; step 3, calcining the pellets at a temperature of at least 1000 DEG C for at least 1.5 hours; and step 4, cooling activated pellets and performing ball milling to obtain the soil conditioner. The soil container contains non-ferrous metal and non-metallic ores, various major, medium and trace elements necessary for the growth of crops, fruit trees and seedlings, and basically no additional major, medium and trace elements need to be added.

The invention belongs to the chemical technique field of organic silicon, and particularly relates to a preparation method of an anti-poisoning silicon rubber. The anti-poisoning silicon rubber is a bi-component addition room-temperature cured silicon rubber, and comprises a component A and a component B, wherein the component A comprises 10-80% of vinyl silicone oil, 5-50% of filler, 0.01-1% of high-activity catalyst, and balance of anti-poisoning agent, and the total weight of the component A is 100%; and the component B comprises 10-80% of vinyl silicone oil, 5-50% of filler and balance of hydrogenous silicone oil, and the total weight of the component B is 100%.The preparation method comprises the following steps of: uniformly mixing the component A and the component B based on a ratio of 1:1 at room temperature, and curing at room temperature. The product prepared by the method can effectively inhibit the catalyst poisoning phenomenon caused by stanniferous and plumbiferous metal ion compounds and sulphureous and nitrogenous organic compounds.

The invention discloses a low-temperature SO2-resistant MnxSby / PG-type SCR denitration catalyst. The catalyst comprises 0.5-4wt% of MnOx as an active ingredient, 0.5-5wt% of Sb2O5 as an assistant, 85-95wt% of attapulgite PG as a carrier, 2-6wt% of glass fibers and methyl cellulose as molding materials, wherein a mass ratio of the glass fibers to the methyl cellulose is (4-30): 1, and 0.1-1wt% of stearic acid and lactic acid as lubricants, wherein a mass ratio of stearic acid to lactic acid is 1: (2-10). The invention also discloses a preparation method of the catalyst. The catalyst has high efficiency low-temperature SCR denitration efficiency, strong SO2-resistant performances and high catalyst reaction activity at a low reaction temperature and can inhibit catalyst SO2 poisoning.

A proton conductor includes a metal ion, an oxoanion, and a molecule capable of undergoing protonation or deprotonation, in which the oxoanion and / or the molecule capable of undergoing protonation or deprotonation coordinates to the metal ion to form a coordination polymer. The oxoanion is preferably a monomer. The oxoanion is exemplified by at least one selected from the group consisting of phosphate ion, hydrogenphosphate ion, and dihydrogenphosphate ion. The molecule capable of undergoing protonation or deprotonation is exemplified by at least one selected from the group consisting of imidazole, triazole, benzimidazole, benzotriazole, and derivatives of them.

The invention relates to a composite catalyst with a titanium dioxide coated gold nanocage structure, as well as a preparation method and application of the composirte catalyst. The composite catalyst comprises an inner core and an outer layer, wherein the inner core is a hollow gold nanocage with a particle size being 200-500nm; the outer layer is a nano titanium dioxide coated layer with a thickness being 5-20nm. According to the composite catalyst, a large quantity of gaps are formed in a gold nanocage layer and a TiO2 nanolayer; by virtue of the gaps, the diffusion of reactants and products can be accelerated; the composite catalyst is capable of firmly limiting the reactants in the inner space and enabling the reactants to reach the extremely-high concentration condition, thereby accelerating catalytic reaction; meanwhile, the composite catalyst is high in reaction activity, small in possibility of catalyst poisoning and capable of greatly improving the catalytic performance, so that the composite catalyst can be widely used in a plurality of composite structural materials with oxides-coated metals.

The invention provides a fuel battery catalyst modified by a metal-organic framework and a preparation method. The preparation method comprises the following steps of uniformly mixing iron powder, benzoic acid, hydrofluoric acid and nitric acid, performing hydrothermal treatment at low temperature, filtering, and drying, so as to obtain a granular crystal matter; performing dry type ball milling,and crushing crystals into micrometer-level powder; performing hot pressing and compounding with a Pt / C (platinum / carbon) catalyst, and uniformly embedding the powder to the back surface of a carbon fiber carrier, so as to form a dot array adsorption layer. The preparation method has the advantages that the metal iron and the benzoic acid organic matters are reacted and are compounded with the carbon fiber carrier to form the dot array adsorption layer; by reducing Fe<3+> into Fe<2+> in a skeleton structure, the selective catalyzing and adsorbing effect is realized for CO (carbon monoxide) adsorbate containing phi bonds; the catalyzing and adsorbing amount of CO in a gas diffusion layer is effectively increased, the risk of catalyst poisoning is reduced, and the reaction activity is improved.

The invention relates to a fertilizer special for saline-alkali land greening, a preparation and application method thereof. The fertilizer special for saline-alkali land greening comprises the following components by mass percentage: 20%-40% of an organic material, 15%-30% of calcium enriched liquid slag, 10%-20% of a humic acid material, 10%-20% of biological fermentation residue, 10%-20% of desulfurized gypsum, 3%-6% of a nitrogen fertilizer, 3%-6% of a phosphate fertilizer, and 0.5%-2% of zinc sulfate. The fertilizer special for saline-alkali land greening provided by the invention generally takes industrial and agricultural waste as the main raw materials, improves light and medium saline-alkali soil through physical, chemical and biological effects, effectively enhances the content of soil organic matters and nutrients, improves soil structure, increases soil aeration and water permeation capacity, prevents soil alkalization, and promotes the root growth of garden plants.

The invention discloses a denitration catalyst with high sulfur resistance and high alkali metal resistance, and a preparation method thereof. The catalyst is prepared by taking tetrabutyl titanate and tetraethyl silicate as carrier precursors, vanadyl sulfate and neodymium nitrate as active component precursors and cerium nitrate and ammonium molybdate as assistant precursors through centrifuging, drying and calcining by adopting a sol-gel process and a coprecipitation process. The prepared denitration catalyst with high sulfur resistance and high alkali metal resistance effectively overcomesthe defects of narrow temperature window, poor alkali metal resistance and poor sulfur resistance of a traditional denitration catalyst. When the temperature is 150-450 DEG C, the air speed is 1000-100000 h<-1>, the SO2 concentration is 0-3000 mg / m<3>, and the K2O concentration of the catalyst is 0-1.5%, the catalyst has an excellent denitration efficiency and an excellent N2 selectivity, and issuitable for nitrogen oxide emission control under flue gas conditions of a coal-fired power plant, a coking plant, a glass kiln, a cement kiln and the like.

The invention discloses corn oligopeptide tablet candies with alcoholism-relieving effects and a preparation technology thereof. The corn oligopeptide tablet candies with the alcoholism-relieving effects are prepared from the following raw materials: corn oligopeptides, semen hoveniae, mongolian dandelion herb powder, sorbitol, kudzuvine root powder, soybean phospholipids, microcrystalline cellulose, ginseng powder, milk thistle seed oil, curcumin, and magnesium stearate. The corn oligopeptide tablet candies with the alcoholism-relieving effects have the following advantages: the corn oligopeptides an the kudzuvine root powder synergistically take an effect so as to inhibit absorption of alcohol by the stomach as well as promote metabolism and excretion of the alcohol from the body, thereby achieving the functions of relieving and inhibiting alcoholism; the semen hoveniae, the mongolian dandelion herb powder and the kudzuvine root powder synergistically take an effect so as to promotealcoholism-relieving, liver-protecting and brain-protecting effects; the soybean phospholipids and the milk thistle seed oil synergistically take an effect so as to enhance liver functions; and the ginseng powder and the curcumin are capable of enhancing body resistance, tonifying Qi and resisting fatigue, thereby promoting restore of body health while achieving the effect of relieving alcoholism.

The invention discloses a daily-use ceramic transparent glaze, which is composed of potassium feldspar, quartz, calcium carbonate, dolomite, high-temperature frit, Tieguanyin mixed tea foam, frit regulator, kaolin, and bamboo powder. The daily-use ceramic transparent glaze contains Tieguanyin mixed tea foam, which can absorb harmful components of lead and cadmium, and meet the health and environmental protection requirements. Adding some bamboo powder can activate the surface of the ceramic, and the surface of the ceramic is more glazed. Delicate and smooth, it makes daily-use ceramics give people a refreshing and moist feeling.

The invention relates to a product for curing heart and brain which comprises (by weight ratio) rhodiola root extract 15-90 parts, taurine 1-40 parts, tea extract 1-20 parts, matrimony vine extract 0-16 parts, glutamine 0-7 parts, arginine 0-6 parts, gluconic acid 0-4 parts, crystalline cellulose 0-5 parts, auxiliary materials 0-20 parts, and lubricating agent 0-2 parts.

A production method of a strawberry flavored refreshing yogurt comprises the following steps: 1, pasteurizing examine-qualified and standardized fresh milk at 95DEG C for 25-30min; 2, cooling to 42DEG C, inoculating, and fermenting to the pH of 4.4-4.6 (or the acidity of 75-80DEG T); 3, pumping ingredients into a high-speed stirring tank with 70-75DEG C water, uniformly mixing a stabilizing agent with sugar and a sweetener, slowly adding obtained material to the high-speed stirring tank, dissolving at 65-70DEG C for 10-15min for uniform dissolution, adding raw milk, stirring for 5min, and cooling to below 45DEG C; 4, uniformly mixing a stabilizing agent solution with a fermentation yogurt matrix, adding water to a constant volume, and mixing and stirring for 20min; 5, adding a composite acid to enable the pH value of the final product of is 4.1-4.2, mixing with an essence, stirring for 10min, and stopping stirring; 6, taking a sample, and detecting indexes of the sample; and 7, carrying out sterilization loading after detection qualification under conditions comprising that the homogenization temperature is 65-75DEG C, the homogenization pressure is 150-200bar, the sterilization temperature is 118DEG C, and the sterilization time is 30s.

The present invention provides vanadium-free rare-earth-based titanium-tungsten powder and a preparation method therefor, and solves a difficulty in improving high-temperature aging resistance and dispersity of a catalyst reactive element or an active-center are increased, and a problem of chemical poisoning of a catalyst. The vanadium-free rare-earth-based titanium-tungsten powder of the present invention comprises the components of: 750-900 parts of titanium dioxide, 10-60 parts of tungsten compounds, 30-60 parts of one or more of cerium compounds, lanthanum compounds and rhenium compounds, and 10-15 parts of complex metal oxide of manganese, molybdenum, nickel (Mn-Mo-Ni-OX). According to the present invention, the catalyst has the characteristics of high-temperature aging resistance and a long service life. The catalyst is free of addition of the reactive element vanadium, and is a real environmentally-friendly catalyst.

The invention provides a metal-based carbon fiber loaded catalyst carrier for a fuel cell and a preparation method. Active carbon fiber is dipped in a copper source and palladium source solution, anddried after ultrasonic concussion is conducted for 24 hours, after that, active carbon fiber is subjected to heat preservation in a reducing atmosphere for 3-4 hours, the heat preservation temperatureis 100-120 DEG C, and metal-based active carbon fiber compositely loading copper / palladium is obtained. The metal-based carbon fiber prepared by the invention serves as a catalyst carrier and can preferentially adsorb microscale gases such as carbon monoxide, nitric oxide and sulfur dioxide which have a great influence on the catalyst, the activity of a Pt catalyst is improved, the capability ofadsorbing gases such as CO and NO is high, the risk of Pt catalyst poisoning can be reduced, the problems that most of traditional catalyst carriers adopt active carbon, the adsorption capability is limited, and the adsorption problem of CO is difficult to solve are effectively solved, and in addition, the catalyst carrier has the characteristics of being low in weight, easy to form and good in toughness.

A proton conductor includes a metal ion, an oxoanion, and a molecule capable of undergoing protonation or deprotonation, in which at least one of the oxoanion and the molecule capable of undergoing protonation or deprotonation coordinates to the metal ion to form a coordination polymer. The oxoanion is preferably a monomer. The oxoanion is exemplified by at least one selected from the group consisting of phosphate ion, hydrogenphosphate ion, and dihydrogenphosphate ion. The molecule capable of undergoing protonation or deprotonation is exemplified by at least one selected from the group consisting of imidazole, triazole, benzimidazole, benzotriazole, and derivatives thereof.

The invention relates to a low-temperature smoke denitration SCR (silicon controlled rectifier) catalyst, which comprises a carrier, a manganese oxide, and composite oxide of one or more of Ce, Zr, Ti, Co, Fe and Cu, the mass content of manganese is 0.1-66 percent, and the total mass content of the Ce, Zr, Ti, Co, Fe or / and Cu is 0-50 percent; and glass fiber and / or kieselguhr is used as the carrier, wherein the glass fiber of the carrier is calcined for 2-4 hours at temperature of 400-600 DEG C, then placed in a nitric acid, sulfuric acid or hydrochloric acid solution with mass concentrationof 5-40 percent for acidizing for 1-8 hours, washed by distilled water to be neutered, dried at temperature of 80-120 DEG C, and crushed to have the fineness of 20-325 meshes. The catalyst uses the glass fiber and the kieselguhr as the carriers, so that the dispersion effect of nanoparticles and specific surface area of the catalyst are increased, the high adsorptive capacity and strong heat resistance and corrosion resistance capacity are achieved, stronger toxic resistance capacity to sulfur dioxide and stream contained in the smoke is realized, the invention can be used for 10-200 DEG C oflow temperature smoke denitration, and has strong water resisting and sulphur toxic resisting capacities.

The invention discloses an ecological improver for heavy metal pollution of soil. The ecological improver is prepared by mixing, by weight, 50-70 parts of calcium oxide, 26-46 parts of humic acid, 1-3 parts of abscisic acid and 1-3 parts of microelements, decomposing and fermenting the mixture and granulating the fermented mixture, has the advantages of effectively regulating the PH value of the soil, significantly increasing organic matter in the soil, supplementing abscisic acid and the microelements in the soil, achieving the obvious repairing effect after being applied to the soil polluted by heavy metals and the like and can be not only used for heavy metal pollution repairing and ecological improving of the paddy farmland soil in the south of China but also used for heavy metal pollution repairing and ecological improving of the dry soil farmland in the south of China. The invention further discloses a preparation method of the ecological improver for heavy metal pollution of the soil.

The invention relates to the technical field of fertilizers. The invention particularly provides a suspended silicon fertilizer as well as a preparation method and device thereof. The suspended silicon fertilizer comprises the following components in percentage by mass: 15%-20% of biological silicon, 1.0%-2.0% of a wetting agent, 2.0%-4.0% of a dispersing agent, 0.1%-0.4% of a thickening agent, 2.0%-4.0% of an anti-freezing agent and the balance of water, wherein the biological silicon is based on SiO2. Bio-silicon is sheared to a nanoscale by shearing, and ammonium ions are adsorbed by the formed silica colloid, immobilizing heavy metal ions. Meanwhile, the lost silicon element in the soil can be supplemented, and the requirement of crop growth can be satisfied.