How to realize the population inversion?

To achieve a population inversion, a system must have more particles in its excited state than in its ground state. This can be achieved through various methods such as pumping energy into the system through an external source, or by creating a low-density environment that makes it easier for excited particles to remain in their excited state. The specific method for achieving population inversion depends on the type of system being used.

相关问题

the master mcu how to realize MPQ70331 window watchdog WDI function

To realize the WDI function of the MPQ70331 window watchdog on the master MCU, follow these steps:

1. Configure the GPIO pin on the master MCU that will be used to drive the WDI input of the MPQ70331.

2. Set the GPIO pin to output mode.

3. Initialize the GPIO pin to a logic high state.

4. Configure the MPQ70331 window watchdog timer according to your application requirements. This includes setting the window size and timeout period.

5. Start the MPQ70331 window watchdog timer.

6. In the main loop of your application, toggle the GPIO pin at a frequency that is faster than the watchdog timeout period. This will keep the MPQ70331 window watchdog reset.

7. If there is a fault or the master MCU hangs, the GPIO pin will stop toggling and the MPQ70331 window watchdog will expire. This will trigger a reset of the system.

By following these steps, you can realize the WDI function of the MPQ70331 window watchdog on the master MCU.

how to realize mysql ngram join tables fulltext search

### 回答1：
To perform a MySQL ngram join tables fulltext search, you can follow these steps:

1. Enable ngram fulltext search in your MySQL server:

You can enable ngram fulltext search by adding the following line to your MySQL configuration file (e.g., `/etc/my.cnf` or `/etc/mysql/my.cnf`):

   [mysqld]
   innodb_ft_server_stopword_table= ''
   innodb_ft_enable_stopword=0
   innodb_ft_min_token_size=2
   innodb_ft_enable_keys=1
   innodb_ft_ngram_token_size=3

The above configuration enables ngram tokenization and indexing for fulltext searches in your MySQL server.

2. Create and populate the tables:

Create the tables you want to join and add a fulltext index to each table using the ngram tokenization technique. For example, if you have two tables, `table1` and `table2`, you can create and populate them as follows:

   CREATE TABLE table1 (
     id INT(11) NOT NULL AUTO_INCREMENT,
     text TEXT,
     FULLTEXT INDEX (text)
   ) ENGINE=InnoDB;

   CREATE TABLE table2 (
     id INT(11) NOT NULL AUTO_INCREMENT,
     text TEXT,
     FULLTEXT INDEX (text)
   ) ENGINE=InnoDB;

   INSERT INTO table1 (text) VALUES ('The quick brown fox');
   INSERT INTO table1 (text) VALUES ('jumps over the lazy dog');
   INSERT INTO table2 (text) VALUES ('The quick brown fox');
   INSERT INTO table2 (text) VALUES ('jumps over the lazy dog');

3. Join the tables:

To perform a fulltext search using the ngram technique, you can join the tables on their fulltext index columns. For example, if you want to find all the records that contain the word "brown" in both `table1` and `table2`, you can use the following query:

   SELECT table1.*, table2.*
   FROM table1
   JOIN table2 ON MATCH(table1.text) AGAINST('brown' IN NATURAL LANGUAGE MODE) AND MATCH(table2.text) AGAINST('brown' IN NATURAL LANGUAGE MODE)

This query joins `table1` and `table2` on their fulltext index columns and performs a fulltext search for the word "brown" using the ngram technique.

Note: Keep in mind that ngram fulltext search can be resource-intensive, especially if you have a large amount of data. You may need to optimize your MySQL server or adjust the ngram tokenization parameters to improve performance.

### 回答2：
要实现MySQL的Ngram连接表全文搜索，你可以按照以下步骤操作：

1. 确保你的MySQL版本支持Ngram全文索引。Ngram索引是一种特殊的全文索引，可以在词组级别上进行索引和匹配。从MySQL 5.7版本开始，Ngram索引被引入并成为MySQL的一部分。

2. 在需要进行全文搜索的表中添加Ngram索引。你需要将需要搜索的文本字段定义为Ngram类型，并为该字段创建Ngram索引。例如，假设你的表名为"table_name"，字段名为"textfield_name"，你可以使用以下命令创建Ngram索引：
ALTER TABLE table_name ADD FULLTEXT INDEX idx_ngram_textfield_name (textfield_name) WITH PARSER NGRAM;

3. 要进行Ngram连接表全文搜索，你需要使用JOIN语句将两个表连接起来，并使用MATCH AGAINST条件进行全文搜索。例如，假设你有两个表名为"table1"和"table2"，它们之间通过字段"field1"和"field2"进行连接，你可以使用以下语句进行全文搜索：
SELECT table1.* FROM table1
INNER JOIN table2 ON MATCH (table1.field1) AGAINST (table2.field2 IN NATURAL LANGUAGE MODE);

注意，这里的关键是使用MATCH AGAINST条件进行全文搜索，并设置适当的匹配模式。你可以根据需要选择不同的匹配模式，如BOOLEAN模式、NATURAL LANGUAGE MODE等。

4. 执行以上查询语句后，MySQL将根据Ngram索引的内容从两个表中进行匹配，并返回与搜索条件匹配的结果。

需要注意的是，Ngram全文搜索可能在大型数据集上性能不佳，因为它需要对每个词组进行索引和匹配。在使用Ngram全文搜索时，你应该考虑数据库性能，并根据实际情况进行性能优化和调整。

### 回答3：
要实现MySQL ngram联接表的全文搜索，需要按照以下步骤进行：

1. 安装MySQL插件：首先，需要安装MySQL插件，以支持ngram搜索功能。在安装过程中，需要注意将插件正确地配置和加载到MySQL中。

2. 创建表：根据需要创建要进行联接的表。确保每个表都具有适当的字段定义，并使用适当的字段类型，例如varchar或text。

3. 添加索引：为了实现快速全文搜索，需要在每个表的相关字段上添加适当的全文搜索索引。对于ngram搜索，可以使用FULLTEXT索引类型。

4. 创建联接查询：编写SQL查询语句，以使用ngram联接表和全文搜索功能。联接查询应该使用JOIN操作符来连接相关表，并在WHERE子句中使用MATCH AGAINST语句来进行全文搜索。

5. 配置ngram参数：通过设置MySQL的ngram参数，可以调整ngram搜索的行为。例如，可以设置ngram的最小和最大字词长度，以及最小的重要性阈值。

6. 测试查询：运行查询语句并测试数据库的响应时间和返回结果的准确性。根据需要，对查询进行调整和优化，以获得更好的性能和结果。

总结起来，要实现MySQL ngram联接表的全文搜索，需要安装插件、创建表、添加索引、编写联接查询、配置ngram参数，并进行测试和优化。这些步骤将帮助您有效地实现所需的功能。