The cycads are called cycads in botany. They are also known as phoenix, bananas, bananas, bananas, cycads, cycads, and cycads. Originated in Central and South China, India, Japan and Indonesia, originated in East Asia and Southeast Asia. Zhejiang, Fujian, Hunan, Sichuan and other places are widely cultivated. Potted plants are provided for indoor viewing in North China and Northwest China. Cycads like sunshine, dry and well-ventilated environment, not cold, good fat, hi sandy soil, slow growth.
The cycads can reach a height of 8 meters in the country of origin, and can be up to 3 meters high in houseplants. The stems are in a thick cylindrical shape with no branching and large leaf marks forming ichthyosis. The cluster of leaves is born on the top of the stem and is a large feathery compound leaf, about 1 meter long. Leaves linear, leathery, hard-edged, thick green with luster, leaf margin rewind. Every spring, 2 or 3 rounds, the old leaves fall off; flowers are unisexual, born on the top of the stem, dioecious, male flowers spirally arranged, resembling a pineapple, being velvety, fresh yellowish at the beginning, becoming mature after brown. The female flowers are large, with a large number of palm-like scales, a flat cylindrical body that gradually splits to form a pine cone. The cycads rarely flowered. The old trees in the 20s to 30ths can bloom. It is called "a millennium-old iron tree." The flowering period is from June to August.
Cycads are mainly propagated in litters and can also be sown or propagated in cuttings.
Seeding and propagation: In October, harvest cycad seeds or full seeds for no more than two years, soak them in warm water of about 50°C for 24 hours, then soak in diluted hydrochloric acid or dilute sulfuric acid for 10 to 15 minutes, and then rinse with water. Change the water one time every other day. After the seed coat is fully water-absorbing and softens, remove the outer seed coat manually, wash away the pulp, dry the seeds, and then store them. Seed sand treatment is performed around December. Because of its thick and hard seed coat, it can be treated with a variable temperature method and finally sanded. Use a clean sandy soil, river sand, perlite and other water-retaining, well-breathable materials to make seedbeds with a thickness of no less than 40 cm and be irrigated with water. The prepared seeds are sown in a bed at a spacing of 5 to 20°C. The depth is about 3 cm. Immediately cover the river sand with a thickness of 3 cm, control the amount of water on the bed and the dryness of the covered fine sand, and then cover the plastic film to moisturize the water after pouring the water. Select the sunny day every morning to open the membrane and let it breathe once. The soil is dry. Watering should be kept moist, cover the film in the afternoon and sunset, and it usually takes 4 to 6 months for the cycas deposit. During this period, the temperature and humidity of the sand should be maintained, and the temperature should be 18 to 25°C and the relative humidity should be 80 to 90%. In order to keep warm in winter, it must not be lower than 12°C. In the second year of May to June the seeds germinate and break out of the shell, and from July to August germination grows a true leaf.
Breeding: In the summer, the buds should be separated from the stems of the mother plants, inserted into the open or pot, half of the earth buried, and the survival rate of the ramets can be as high as 80 to 90%, and the sucker growth is slow. It is better to take out the buds after 3 years. The sucker wounds are easy to live. The stem can also be cut into long sections of 15 to 20 centimeters and buried in sandy soil to create new shoots around the cadres and then subcultivated.
The cycads are suitable for growth in direct sunlight or under bright scattered light. Summer is best shaded half, the temperature is maintained at 15-20°C, the soil and air humidity are greater, and the leaves should be sprayed frequently. The plant does not have a dormant period, and the winter temperature is preferably 12 to 16°C, and the plants have a considerable degree of cold resistance. Between 3 and 9°C months, liquid fertilizer should be applied once a month. It is advisable to use a mixture of organic matter, peat and fine sand as the substrate for cultivation. Every 2 to 3 years, change the basin soil, add new soil and basal fertilizer to help grow. Liquid fertilizer can be applied several times in summer, and ferrous sulfate solution can be added to make the leaf color more dark green. After the fall, the amount of watering is reduced. The pests and diseases of cycads are most commonly caused by scale insects. The first step is to maintain good ventilation and find the scale insects. Observe the limestone mixture or fluoroacetyl ammonium at hatching.
Ventilator block diagram
One. Main mechanical ventilation modes
(1) Intermittent Positive Pressure Ventilation (IPPV): positive pressure in the inspiratory phase and zero pressure in the expiratory phase. 1. Working principle: The ventilator generates positive pressure in the inspiratory phase and presses the gas into the lungs. After the pressure rises to a certain level or the inhaled volume reaches a certain level, the ventilator stops supplying air, the exhalation valve opens, and the patient's thorax Passive collapse of the lungs and exhalation. 2. Clinical application: Various patients with respiratory failure mainly based on ventilation function, such as COPD.
(2) Intermittent positive and negative pressure ventilation (IPNPV): the inspiratory phase is positive pressure and the expiratory phase is negative pressure. 1. How it works: The ventilator works both in the inspiratory and exhaled phases. 2. Clinical application: Expiratory negative pressure can cause alveolar collapse and cause iatrogenic atelectasis.
(3) Continuous positive pressure airway ventilation (CPAP): Refers to the patient's spontaneous breathing and artificial positive airway pressure during the entire respiratory cycle. 1. Working principle: Inspiratory phase gives continuous positive pressure air flow, and exhalation phase also gives a certain resistance, so that the airway pressure of inhalation and exhalation phases are higher than atmospheric pressure. 2. Advantages: The continuous positive pressure airflow during inhalation is greater than the inspiratory airflow, which saves the patient's inhalation effort, increases FRC, and prevents the collapse of the airway and alveoli. Can be used for exercise before going offline. 3. Disadvantages: great interference to circulation, large pressure injury of lung tissue.
(4) Intermittent command ventilation and synchronized intermittent command ventilation (IMV / SIMV) IMV: There is no synchronization device, the ventilator air supply does not require the patient's spontaneous breathing trigger, and the time of each air supply in the breathing cycle is not constant. 2. SIMV: There is a synchronization device. The ventilator gives the patient a commanded breath according to the pre-designed breathing parameters every minute. The patient can breathe spontaneously without being affected by the ventilator. 3. Advantages: It exerts its ability to regulate breathing while offline; it has less influence on circulation and lungs than IPPV; it reduces the use of shock medicine to a certain extent. 4. Application: It is generally considered to be used when off-line. When R <5 times / min, it still maintains a good oxygenation state. You can consider off-line. Generally, PSV is added to avoid respiratory muscle fatigue.
(5) Mandatory ventilation per minute (MMV) When spontaneous breathing> preset minute ventilation, the ventilator does not command ventilation, but only provides a continuous positive pressure. 2. When spontaneous breathing is less than the preset minute ventilation volume, the ventilator performs command ventilation to increase the minute ventilation volume to reach the preset level.
(6) Pressure Support Ventilation (PSV) Definition: Under the prerequisite of spontaneous breathing, each inhalation receives a certain level of pressure support, increasing the patient's inhalation depth and inhalation volume. 2. How it works: The inspiratory pressure begins with the patient's inspiratory action, and ends when the inspiratory flow rate decreases to a certain level or the patient attempts to exhale hard. Compared with IPPV, the pressure it supports is constant, and it is adjusted by the feedback of the inspiratory flow rate. Compared with SIMV, it can get pressure support for each inhalation, but the level of support can be set according to different needs. 3. Application: SIMV + PSV: used for preparation before off-line, can reduce breathing work and oxygen consumption Indications: Exercise the ventilator; prepare before going offline; the ventilator is weak due to various reasons; severe flail chest causes abnormal breathing. 5. Note: Generally not used alone, it will produce insufficient or excessive ventilation.
(7) Volume Supported Ventilation (VSV): Each breath is triggered by the patient's spontaneous breathing. The patient can also breathe without any support and can reach the expected TV and MV levels. The ventilator will allow the patient to be truly autonomous Breathing also applies to preparations before going offline.
(8) Capacity control of pressure regulation
(IX) Biphasic or bilevel positive pressure ventilation How it works: P1 is equivalent to inspiratory pressure, P2 is equivalent to breathing pressure, T1 is equivalent to inspiratory time, and T2 is equivalent to exhalation time. 2. Clinical application: (1) When P1 = inspiratory pressure, T1 = inspiratory time, P2 = 0 or PEEP, T2 = expiratory time, which is equivalent to IPPV. (2) When P1 = PEEP, T1 = infinity, P2 = 0, T2 = O, which is equivalent to CPAP. (3) When P1 = inspiratory pressure, T1 = inspiratory time, P2-0 or PEEP, T2 = desired controlled inhalation cycle, equivalent to SIMV.
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